# PM-940m CNC - VS Motion Controller Conversion to Centroid Acorn



## pburgh

Originally, I was going to CNC a PM-940m with hardened ways from the ground up.   When I started to gather the components for the build, I ran across the Centroid Acorn controller, and that was the first component I purchased.   But during the course of starting the process, I decided to switch gears and purchase a turnkey machine instead and give that a try.  Once I received the machine and checked out the nMotion controller with Mach 3, I decided to switch it out with the Acorn controller.  One reason was that there is not a lot of information on the nMotion controller, and another is that I don’t have any experience with Mach 3.  With all of the issues that I’ve read about Mach3, I decided to focus my efforts on switching to the Acorn controller and becoming familiar with the Centroid control software.  This thread will document the process and I hope that others who have similar machines and want to change the controller/software will benefit from the information gathered here.  Please feel free to share your knowledge and opinions during this process.
There is a wealth of information on the Centroid Acorn site page and Centroid’s Acorn forum.  I will post the links below in the outline to get this started.

The general outline will be as follows:

Gather information on the Centroid Acorn setup
http://www.centroidcnc.com/centroid_diy/acorn_cnc_controller.html has links to all of the info needed for this setup
Focus on the Lead Shine schematic for this setup
The videos link has detailed videos in order on setting up the controller

Compare and match the nMotion schematics to the Acorn schematics
Identify wiring matchups and changes needed.  Determine what’s missing (5v power supply, momentary jog contact for limits)
Know that the wiring numbers may vary from machine to machine (thanks Jake)
This link to a post I created in the forum will fill in some of the info from questions that I had: http://centroidcncforum.com/viewtopic.php?f=60&t=1270
Document the changes needed for getting motion working on the machine with peer review

Focus on the Spindle/VFD setup
Formulate and verify the necessary changes through peer review
Test Spindle function

Look into adding flood coolant pump, lube pump, etc to outputs
I have already setup my computer and have bench tested the Acorn card according to the instruction videos.  I followed Centroid’s recommendation on setting up an Intel NUC with Windows 10 Pro and I’m using a Viewsonic 24” touch screen monitor.


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## phazertwo

YES!  Sub'ed and can't wait to see this thing in action!

I hope to be only a step or two behind you in this whole process!  Building my new computer tonight!

PZ


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## cut2cut

Yup,  right there with you both!  I already have my computer setup and the 5v+24v power supply.  Just waiting for the Acorn which should show up by the weekend.  Cheers !
Jake


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## pburgh

Great to hear guys!  I'm pondering on how best to mount the new card in place of the nMotion card.  I'd like to mount it perpendicular to the back board so i can leave space for a 4th axis drive if i go that direction.  How are you all looking to mount yours?
Regards,
Doug


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## pburgh

Hey All,
Here is a good video that I found on you tube giving an overview of using the Centroid software:  




Enjoy!
Doug


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## cut2cut

pburgh said:


> Hey All,
> Here is a good video that I found on you tube giving an overview of using the Centroid software:
> 
> 
> 
> 
> Enjoy!
> Doug



It is very good !  By coincidence I watched it this morning!
Good news,  I have the Acorn moving all axis and also the spindle is spinning, and the e-stop working.
Initially I had not run the 24v jumper so the E stop was not functioning but would almost work but only upon restart of the program.
Unfortunately the E stop switch that comes with the PM940 does not mechanically function as Normally Closed.  It has only two wiring terminals.  The default wiring for the limit and home switches is also NO.  I am not sure if they can be wired as NC as that’s preferable.  Something to check.
The axis direction and axis STEP and DIR had to be inverted in the setup wizard, yours may not?!  Also currently the spindle appears to be spinning the wrong direction but I need to verify that.  There doesn’t appear to be a software fix.  Likely two of the motor wires just need to be swapped on my 3 pole inverter motor.

More details to follow.    The most pressing issue for me is to figure out why it persistently runs a default flange program when I hit the cycle start button.  I have to quickly hit cycle stop which aborts the job, then I can jog around.

Anyway,  good progress today, but hit a few snags, but nothing bad at all. 

Jake


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## cut2cut

HUGE note to avoid a crash while setting the software up or if you want test new hardware without it running a job.  EVERY time you hit cycle start Centroid CNC software v12 will open the last job file you used.   In my case it was "FLANGE. xxxx "  something like that.    It was probably loaded by the person that tested my card at the factory, or maybe its the default?  Regardless,  while you are troubleshooting the conversion to Acorn, you'll undoubtedly need or want to jog around to see if things are working you'll have to hit "cycle start ".  What happens right away is it will load and start performing the last job / program you loaded.  It will persist.  This is a good function as it doesn't require you to find a file before continuing with the job you started the day before.

The solution is to create a "--NULL--" file that you load.  It shouldn't have ANYTHING in it.  Then you'll just load that file after you are done with a real "job/program"  Thankfully someone posted that solution in October.

Note: I have not turned on "Home to Switch" yet, so this may change the behavior possibly? 

Jake


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## pburgh

Good to know Jake,  thanks for the heads up on all of this.  That's fantastic that you've made this much progress.  It's been unusually cold here in Florida, so I didn't work out in the garage as much as i'd liked to yesterday.  I'm hoping to get more time today and i'll check out how my limits are wired for NO or NC.  I didn't ring them out yet, but I'm going to have to get into each one to determine the colors they used for each wire on the common.  Plus i'm still mulling around how I want to mount everything to take full advantage of the space.  
Regards,
Doug


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## phazertwo

Very interesting, thanks for the heads up Jake!

PZ


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## phazertwo

I started getting into the wiring on the 940 last night in preparation of the Acron showing up today.  The limit switches can be wired NO or NC, there is an extra set of terminals inside the switch.  On another note EVERY wire in my limit switches was loose, and one was even broken.  No wonder my limits never worked right with M3...  All better now!

Also, on my mill (ordered Jan 2016) there is a yellow wire that is not used in the step/dir cable going to the stepper drives.  I Pulled that out for each axis and will use it as the enable.  Also, the back plane in mine had holes for the drives to be moved to the right, I would assume to make room for the 4th axis.  I went ahead and moved the drives over to create a little extra room for the Acorn.  I'd post pics but it looks like the local squirrel population did a number on the phone line going into my house...  So my interwebing is reduced to what I can do on breaks at work...

PZ


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## pburgh

Hey PZ,  great to hear that you're all set. And thanks for the info on the switches.   I guess by having to do this we'll have better mills from the experience.  I know that the qc on mine isn't what I would have expected.  Things being loose and all.   I also have a wire going to the swingarm control box that is just cut off in the control cabinet.  But hey what can we do.  Did you see the post in the thread from the Centroid site?  One of the techs there responded and said we didn't have to use the ENA feature if it wasn't used in the mill.  Don't know if that makes a difference, but it's there.
Regards,
Doug


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## cut2cut

Nice finds PZ !  Sorry about the squirrels :-(

guys, check out this video of a centroid software feature.  This is awesome !   Now I'm researching probes again... damn expensive, but ....






Jake


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## phazertwo

pburgh said:


> Hey PZ,  great to hear that you're all set. And thanks for the info on the switches.   I guess by having to do this we'll have better mills from the experience.  I know that the qc on mine isn't what I would have expected.  Things being loose and all.   I also have a wire going to the swingarm control box that is just cut off in the control cabinet.  But hey what can we do.  Did you see the post in the thread from the Centroid site?  One of the techs there responded and said we didn't have to use the ENA feature if it wasn't used in the mill.  Don't know if that makes a difference, but it's there.
> Regards,
> Doug



Yeah, I'm honestly not sure what the enable circuit does for you... but I figure it's there, the wire is there, and it's in the Acorn wiring diagram I'll hook it up and see if she chooches.

Looks like the Acorn was delivered... I can't believe how excited I am about this, it's like I'm 5 years old and it's Christmas day!

PZ


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## pburgh

I tell my wife every day is Christmas.  She tells me that the only difference between men and boys is the price of their toys.     I hope it all meets your expectations.  I have a good feeling about this product.


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## pburgh

cut2cut said:


> Nice finds PZ !  Sorry about the squirrels :-(
> 
> guys, check out this video of a centroid software feature.  This is awesome !   Now I'm researching probes again... damn expensive, but ....
> 
> 
> 
> 
> 
> 
> Jake


Jake,
Alan has some good videos.  He seems to be very happy with Centroid and Clear Path.  I purchased the basic probe from Tormach to give it a go.  But I came across probe called a Hallmark that's made by a guy in New Zealand  that might be at a better price point than say one from Centroid.  Here's a video of how he came about it.  There are others showing his development of the probe.  



  I think it goes for between 600 and 700 dollars.


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## phazertwo

I have been keeping half an eye on the Hallmark ITTP (Impact Tolerant Touch Probe).  It looks like a nice probe, but I thought he wasn't really selling them yet?  Either way it's on the list of tools that would be nice to have, especially with the probing routines available in CNC12.

Got my Acorn bench tested last night, and modified the cabinet so the Acorn will be mounted near the same location as the old nMotion.  Couldn't find standoffs to get it mounted though, so I had to call it a night.  Hoping to pick some of those up on the way home tonight, get the Acorn mounted in its new home, mount the new 5v power supply and see if I can get some motion out of it!

Also, Jake was defiantly correct about the e-stop on the 940 being a NO circuit... which is super sketch.  China never ceases to amaze me with corner cutting.  I can't imagine there is much of a cost savings in using a NC switch instead of a NO switch, and with the nMotion and M3, its just a flip of the active high/low on that input to change it...  Anyway, lucky for me I happen to have a few switches from some equipment that I scrapped, but important for others doing the swap to know, you will need to replace the e-stop with a NC.  Actually not a bad idea to switch it out anyway, a NO e-stop circuit is dangerous.

PZ


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## pburgh

hey PZ, thanks for the heads up.   I really didn't want to have to change things around that much with the limits, but oh well.  I actually bought a new Estop switch when I bought my Acorn and was going to do the machine from scratch.  Looks like i'll have to put it to use.  To save room I made a backing plate for the controller and i'm going to stand it off of the main board around 3" with all thread.  Underneath that i'm going to mount the power supply against the main board.  Hopefully I wont get any interference.  This way i'll have the space to add another drive if needed.  
On the probe, do a search on YT.  There is a guy who just reviewed the Hallmark so I think they are for sale.  I'd like to get the one from Centriod, but I want to get some experience with using one of these before i'd go with that amount of money (and the big boss would kill me).  They are expensive, but i'm sure they are high quality.


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## phazertwo

Looks like he is taking email orders...I don't really want to inquire about one since I cannot afford it at the moment, but it would be nice to know how much it costs.

This is the video that made me dig deeper into it.  The CNC4RX7 guy seems to make some decent, informative videos.






PZ


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## pburgh

Yeah, Sam is very good researching stuff.  When I was going to build my CNC 940, I purchased his plans and documentation to give me a jump on trying to gather all of the info. I think it was $40.00.  I don't mind contributing some when folks give you good info.  Helps save time.  Even though he did the 727, a lot of what he did translated to the 940.   For the probe,  I did see some pricing down in the comments on one of the videos.  Not sure if it was Sam's.

Regards,
Doug


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## pburgh

Hey Guys, finally starting to make progress.  I got the power supply and controller mounted in the cabinet the way I wanted.   I wanted to try to maximize space for a future 4th drive.  But also wanted to be sure that the power supply won't interfere with the controller.   I hope to get things wired in the next couple nights.  Hopefully i'll be able to use the existing shielded cable, but I may have to buy some more.  I posted some pics on how they are mounted.


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## pburgh

PZ, Sam has the price listed at the top of his video.  Here's what he has listed:

*Published on Aug 5, 2017*

In this video I am excited to show you the Hallmark Design Ltd. Impact Tolerant Touch Probe. This Touch probe is made specifically to provide precision and accuracy while being Tolerant of impacts in all directions. ( NO MORE BROKEN STYLUS)  I was selected as a Mach 3 user to do some beta testing,  The probe was originally designed for the Tormach PCNC machines. As you know Mach3 does not come standard with Auto probing routines and the few I found on the Zone were not what I was looking for so I have modified these extensively to work well with the I.T.T.P. Some testing is still needed but as shown in the video they work quite well.  If you would like more information you can contact me. Please comment and let me know if the content is spot on or you would like more information and details.Thanks for watching , please subscribe, thumbs up if you like the video, and most importantly , Be Safe!

*Pricing: $695 $20 shipping to USA*
Contact info: https://www.youtube.com/user/Threadex...


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## phazertwo

Wow, that's about half cost of the Centroid DP-4... But still way more than the cheapo Tormach unit.  Hopefully you get what you pay for and judging by Sams review, you do.

It would seem that your panel layout is quite a bit different than mine.  Can you snap an overall shot of the cabinet layout, I would like to see how yours is done.  If I ever get my internet situation figured out I'll post some pics of how I mounted mine.

PZ


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## pburgh

Hey Guys,
Did you have to do anything to switch input voltage on the meanwell power supply?  I don't see a selector switch, and there is notihing on the online doc, so i'm assuming it's auto-ranging.
Regards,
Doug


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## phazertwo

pburgh said:


> Hey Guys,
> Did you have to do anything to switch input voltage on the meanwell power supply?  I don't see a selector switch, and there is notihing on the online doc, so i'm assuming it's auto-ranging.
> Regards,
> Doug



Is the voltage out of range?  I checked mine before I bench tested and it was 24v on the nose.  Also, looks like it might be too late for you, but I just used the 940's factory 24VDC power supply... made things a little easier and cleaner.

Anyway, I finally have real internetz at my house again!  So here are some pics of how I mounted the Acorn, should leave me plenty of room for a 4th driver in the future... (let me know if you cannot see the pics, I've never posted pics like this...)







The system is powered up, for some reason I don't have motion, though I suspect it has something to do with the enable circuit ,hopefully I will get that figured out tomorrow.  Also it turns out that you don't need to re-wire the switches, replace the e-stop, or anything, you can just select NO instead of NC in the wizard.  NC is still a much better/safer way to go, so I'm still going to swap out the e-stop.

Cabinet still needs it's final clean up, but will happen after she's tested out and I'm 100% sure i'm not going to change wiring again.

Here is a link to the 5v power supply I used.  I wanted something small and DIN mounted.
https://www.amazon.com/gp/product/B01HTH3LSE/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

Also, here is the E-Stop that I'm going to use.  Should be a drop in replacement
https://www.amazon.com/gp/product/B0094GM004/ref=oh_aui_detailpage_o00_s00?ie=UTF8&th=1


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## pburgh

Wow PZ,  your cabinet is wired a little different than mine.  I asked about the power supply because I didn't want it to be damaged if I had to manually set the input voltage.  I didn't see anything that would indicate that on the new meanwell dual output voltage power supply, but I wanted to be sure that the input voltage was auto-ranging.  The 24v power supply that came with the mill has a warning tag of setting the input voltage switch on the power supply, but I can't see a selector switch.  I swapped out the e-stop with one with a NC contact and added a jog switch for the series limits.  In the process now of switching the limits to NC and tracing out the commons so I hook them up right.  Luckily there was a spare wire going to the control arm, so I was able to wire the jog switch easily.  I was going to pull some extra wire to the control arm box, but it's not as easy as I suspected it would be.  They used a spiral wrap on the wires and it's acting like a Chinese finger.  I don't want to remove all of the wiring and pull it all back in again.  So for now I'll just leave it as it is.  Hopefully, i'll get some time tomorrow to work on it in the morning.  it's getting cold here again, and it makes it uncomfortable to work in the garage.  I'm losing my northern blood.  Been in Florida too long.
Regards,
Doug


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## phazertwo

You should snap a picture of your cabinet.  I'm interested to see what the layout looks like.

PZ


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## pburgh

Sorry I thought I posted pics.  Here they are.


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## qualitymachinetools

Looks GREAT!


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## phazertwo

Well I got mine running last night.  I spent a about an hour pulling my hair out trying to figure out why the X-axis just would not go.  It was making crazy noises even when it wasn't be actuated.  Turns out that that A+ and B+ wires were loose in their ferrules, so it had intermittent connection.  Got those re-ferruled and BOOM!  SHE'S ROCKIN'!

I got the X-axis tuned, and I'm running 125 IPM on X and Y which is 25IPM faster than with the nMotion and it seems way smoother!  The high today is 25°F so I'm not going to be making it out to the garage tonight.  But there is light at the end of the tunnel!

PZ


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## pburgh

That's great to hear PZ.  I'm hoping to get mine running tonight.  Still have to be sure that the VFD is connected correctly.  My wiring was different than Jake's, so I have to take a closer look.
Regards,
Doug


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## cut2cut

Hi guys,  sorry for not seeing your posts.  I was busy but also the list wasn’t sending me notifications.  I just assumed you guys weren’t working on your mills but obviously that’s not the case !! Wow,  both of your wiring looks great.  Mine looks like a speghetti dinner.... 
anyway... great work guys.

So, the  5v 24v power supply automagically accepts whatever input voltage so you don’t need to flip a switch or anything.  120 or 240 works fine.    
As far as the vfd wiring,  I believe you can bypass the relays altogether and run the wires direct.  From what I was instructed they don’t serve a purpose in our setup.    Lemme know and I can send you a better diagram, if that would help at all. 

Cheers,  Jake


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## cut2cut

Oh, and yeah, i’ve been eyeballing the Hallmark too,  it’s tough to pull the trigger on something so expensive but would really make cnc life easier.  The crash tolerance aspect is great insurance.  I guess my main question is whether it can be used as effectively ( or at all ) to “digitize/scan” as the Centroid probe can.  I imagine so, but I still wonder if there could be some difference ?  If anyone knows, please say something.  I’m itching to order the hallmark !


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## phazertwo

You are correct, we don't need the relays.  I left them in there just because they are already there.  If I need to mount something else in there, or I need a set of relays (power draw bar), they will be there and ready to rock.

Also, for those that may be lerking thinking about a centroid swap, or are just looking for a CNC computer, my dad just got this one and has been running CNC12 on it completely unmodified:
https://www.newegg.com/Product/Product.aspx?Item=9SIA7RB3SP1196&ignorebbr=1

That's a functioning computer that scores 1745 on the single thread performance benchmark WITH windows 10 for $120.  Hell windows 10 cost me $150, and the components I bought to upgrade my old computer were another $150!  And my comp only scores a 1757!  Add a little flash drive like this:
https://www.amazon.com/gp/product/B01MZ2OWDT/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

and you have a rocking little CNC computer!  Even came with a mouse and keyboard.

PZ


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## cut2cut

Nice heads up about the computer.  I got a dell optiplex with windows 7 last year and upgraded to windows 10.  It scores similarly I think.
I have an Asus touch screen which feels laggy in the Centroid interface which worries me a bit.  The computer is not connected to the internet, so I hope it’s not trying to connect even though I turned off everything per the Centroid Windows setup video. 
Jake


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## phazertwo

I noticed that my computers response was a bit laggy in CNC12 also, however it went away after I got my settings squared away.  I can't quite bring myself to drop the $$$ on a touch screen... Though it seems like it really would make things nicer, not having to have a keyboard laying on my tool box all the time, and finding space for the mouse.

I think I'm going to save my pennies for a pendent, when ever that comes out.

PZ


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## cut2cut

I think a keyboard is probably still required for punching in numbers.
I do miss my pendant already.


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## pburgh

cut2cut said:


> Hi guys,  sorry for not seeing your posts.  I was busy but also the list wasn’t sending me notifications.  I just assumed you guys weren’t working on your mills but obviously that’s not the case !! Wow,  both of your wiring looks great.  Mine looks like a speghetti dinner....
> anyway... great work guys.
> 
> So, the  5v 24v power supply automagically accepts whatever input voltage so you don’t need to flip a switch or anything.  120 or 240 works fine.
> As far as the vfd wiring,  I believe you can bypass the relays altogether and run the wires direct.  From what I was instructed they don’t serve a purpose in our setup.    Lemme know and I can send you a better diagram, if that would help at all.
> 
> Cheers,  Jake



Hey Jake,
If you have the VFD figured out i'd like to see how you wired the connections.  I know you had mentioned a couple weeks ago that our setups were different.   I'm not quite sure how this should be connected.  Tomorrow night I hope to finally finish hooking everything up and firing this thing up.  
Thanks,
Regards,
Doug


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## pburgh

Hey Guys,
I also wanted to talk to you about your thoughts for a power draw bar.  I was watching a video on YT and a guy from Australia purchased a 3 stage cylinder like the one that Tormach  makes from a company in China and setup his power drawbar.  I took a chance and purchased the same cylinder and valve that he did from China and it should be here the beginning of next week.  Take a look at the video and let me know what you think.  



Also, i'm not sure if you've looked at Hoss' site for info, but it looks like his site is gone.  He had a lot of good info on there.  The site was www.hossmachine.info

Regards,
Doug


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## cut2cut

pburgh said:


> Hey Jake,
> If you have the VFD figured out i'd like to see how you wired the connections.  I know you had mentioned a couple weeks ago that our setups were different.   I'm not quite sure how this should be connected.  Tomorrow night I hope to finally finish hooking everything up and firing this thing up.
> Thanks,
> Regards,
> Doug



Hey Doug,

Here is the schematic you'll want to use if you keep the relays.  However, to keep it simple and not create unwanted noise you should really just run two new shielded wires from the Acorn directly to the VFD for the ( without going through the terminal block ).  AN_OUT on the Acorn to AVI on the VFD.  And AN_GND from the Acorn to the ACM on the VFD.

Then for the M1, M2 and DCM on the VFD use the rest of the wiring diagram enclosed ( if you intend to keep using the relays ).
Note, the lower right corner shows the KA1 and KA2 terminals ( 1,5,9, 13 and 14 ).  I believe your 029 and 031 are identical to the wiring used in my mill, specific to the VFD anyway..... so this schematic should work for you as well.  Note, you may have to rewire your relay, possibly,  but hopefully not !   I can't say because I previously changed mine to wire for the Mesa 7i76e / LinuxCnc.
Let me know if you have any more questions.

Jake


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## cut2cut

OR you could make life simpler, and remove the relays *AND remove the power supply ground and 24v+ from this schematic too* !!!  in this scheme you should NOT connect COM ( adjacent to the OC4 and OC5 )  on the Acorn to the power supply ground,  if you do it will create a ground loop.   I assume the COM near OC4 and 5  aren't connected to the COM in other places on the Acorn board.    AND NOTE, the OC5  wire jumps over  the COM wire.  They aren't connected [ to each other ]


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## cut2cut

pburgh said:


> Hey Guys,
> I also wanted to talk to you about your thoughts for a power draw bar.  I was watching a video on YT and a guy from Australia purchased a 3 stage cylinder like the one that Tormach  makes from a company in China and setup his power drawbar.  I took a chance and purchased the same cylinder and valve that he did from China and it should be here the beginning of next week.  Take a look at the video and let me know what you think.
> 
> 
> 
> Also, i'm not sure if you've looked at Hoss' site for info, but it looks like his site is gone.  He had a lot of good info on there.  The site was www.hossmachine.info
> 
> Regards,
> Doug



Can you share exactly where you got the cylinder and valve ?  I might do the same!  Thanks

Jake


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## pburgh

Absolutely!  Mine should be here on Monday.  I thought the pricing was good.  Here's the info and her response back with pricing and all:
Here's their website:

http://www.xinyipneumatic.com/
http://www.airpneumetics.com/

Her response, model numbers and pricing:

Thanks for your inquiry. 

 CQ2100X 12-3 US$160/PCS

 4V310-08 US$10/pcs Do you need DC12V or DC24V ?  (I told her 24v.)

Shipping cost US$80  ( be sure to let her know your shipping location.  This price may vary for you.)

 Total: US$250

> > If you confirm the order I can send invoice to you by paypal ..

> > Any question, Pls let me know .

> > Best regards
> > Vicky jin
> > Sales Manager
sales@xinyipc.com.cn

Let me know what you think.
Also, thanks for the info on the VFD.  That was very helpful.  I should be able to fire up the mill tonight with any luck.
Regards,
Doug


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## pburgh

Jake,
So you recommend eliminating the relays as a way to go?   I could do that.  I'll have to stop and see if I can get some shielded cable.  Do you have a place on line that you like for purchasing shielded cable?
Thanks,
Doug


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## cut2cut

pburgh said:


> Jake,
> So you recommend eliminating the relays as a way to go?   I could do that.  I'll have to stop and see if I can get some shielded cable.  Do you have a place on line that you like for purchasing shielded cable?
> Thanks,
> Doug



Hi Doug,
Considering the existing wire to and from the relays isn’t shielded ( mostly ).  You can probably use unshielded there for now.  I believe the other two should be however.  Consider using a Cable with extras there so you can take advantage of the fault and reset modes the VFD provides.  I haven’t wired those yet but it’s probably worth preparing for as the Acorn can sense and send those signals to correct a VFD fault.   Let’s say you over power the VFD and it trips a failsafe.  It would be nice for the job to stop right then saving us from a bad crash if it wasn’t attended.
I’ll wait until your power bar air cylinder arrives to order mine.  Seems like a good idea since this isn’t at the top of my to do list.  Hopefully you don’t experience any hitches and it’s a good place to buy from A to Z !  Thanks,
Jake


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## pburgh

That sounds like a good idea.  I'll have to see where I can get some multi conductor cable.  Lowe's/Home Depot only have 2 and 4 conductor in shielded cable.  Any suggestions for who has cable for sale online that's reasonable.
Regards,
Doug


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## cut2cut

pburgh said:


> That sounds like a good idea.  I'll have to see where I can get some multi conductor cable.  Lowe's/Home Depot only have 2 and 4 conductor in shielded cable.  Any suggestions for who has cable for sale online that's reasonable.
> Regards,
> Doug


Sorry,  I don’t have great suggestions there.  Automation technologies inc has some by the foot ( dollar roughly per foot ) but I don’t know if it’s solid or stranded.   Recently I was considering using shielded Ethernet cable that is waterproof and can be buried , but can only get large quantities and it’s pretty small gauge.  I almost did it... but my brother came through with what I needed from his own stockpile of old wire.)

Jake


----------



## phazertwo

I'm not sure how many conductors you're going to need, but here is an example of what is available on Amazon.  I just typed in 6 conductor shielded cable.  It's $1.25/ft shipped.

https://www.amazon.com/Coleman-Cabl...56&sr=8-3&keywords=6+conductor+shielded+cable

PZ


----------



## pburgh

cut2cut said:


> OR you could make life simpler, and remove the relays *AND remove the power supply ground and 24v+ from this schematic too* !!! in this scheme you should NOT connect COM ( adjacent to the OC4 and OC5 ) on the Acorn to the power supply ground, if you do it will create a ground loop. I assume the COM near OC4 and 5 aren't connected to the COM in other places on the Acorn board. AND NOTE, the OC5 wire jumps over the COM wire. They aren't connected.



Hey Jake,
Just so i'm clear on this, would I use the COM between OC4 and OC5, or would I use the VFD/COMMON that is a couple of terminals above OC5? 
See the pic below:







Also, when you say remove the power supply ground i'm not sure what you mean.  I disconnected the +24 to the relays from the load side of the breaker eliminating them and ran a new wire directly to the Acorn from the breaker.  For the other shielded cable for AN_OUT and AN_GND, did you ground the shield like it shows in the diagram?

Thanks, 
Doug


----------



## cut2cut

I


pburgh said:


> Hey Jake,
> Just so i'm clear on this, would I use the COM between OC4 and OC5, or would I use the VFD/COMMON that is a couple of terminals above OC5?
> See the pic below:
> View attachment 254932
> 
> 
> 
> Also, when you say remove the power supply ground i'm not sure what you mean.  I disconnected the +24 to the relays from the load side of the breaker eliminating them and ran a new wire directly to the Acorn from the breaker.  For the other shielded cable for AN_OUT and AN_GND, did you ground the shield like it shows in the diagram?
> 
> Thanks,
> Doug



I'm fairly certain the two connectors you are pointing at are common to each other.  You could test this with a meter just to be sure, but I believe they are.  Currently I'm using the relays.  I am using the COM between OC4 and OC5 and all is working fine, so you could try that first I suppose.

In the NON Relay wire scheme you do not want  to use either the 24v or Common/Ground from the power supply for the VFD / Acorn section.  

However you should wire the Acorn to the 24v power supply per the Centroid manual  (as is normal for any setup) and all should be good.

I believe the shield in the AN_OUT / AN_GND  is grounded to the acorn ground in the main Acorn power block ( where the power supply connects to the Acorn )  but I'd have to recheck that.  It makes sense, though.

Jake


----------



## cut2cut

guys,  keep this link handy. It might apply to us... and also save us from having to use a 5v power supply at all.
Why ?  because this happened to me once tonight... upon starting the system after turning it off for a break. Thankfully I just made sure my wires were not loose and rebooted twice and it all worked again.  Spooked me a bit, however.
http://centroidcncforum.com/viewtopic.php?f=60&t=1395&start=10


----------



## phazertwo

That's very interesting.  I had a similar issue when I first started running the Acron and it was very frustrating, I chased it back to a miss wired +24vdc on the input strip.  I missed it by one terminal and it was going into an input terminal, not the +24vdc terminal.  In my chasing I also realized that the common between all the axis terminals were not always ringing out with continuity, so I jumped them all together.  I don't know it if really helped anything, but it certainly isn't hurting anything.

Anyway, was playing around with tuning again last night.  I think I have the X and Z nailed, however the Y is fighting me...  I Just need to figure out how to fixture the 1-2-3 blocks better.

https://photos.google.com/share/AF1...?key=OEZHX1BHX3VhOHJfR1NJV2VnM3MwcmwwdkIzWmJn

Let me know if the video doesn't work...

PZ


----------



## cut2cut

phazertwo said:


> That's very interesting.  I had a similar issue when I first started running the Acron and it was very frustrating, I chased it back to a miss wired +24vdc on the input strip.  I missed it by one terminal and it was going into an input terminal, not the +24vdc terminal.  In my chasing I also realized that the common between all the axis terminals were not always ringing out with continuity, so I jumped them all together.  I don't know it if really helped anything, but it certainly isn't hurting anything.
> 
> Anyway, was playing around with tuning again last night.  I think I have the X and Z nailed, however the Y is fighting me...  I Just need to figure out how to fixture the 1-2-3 blocks better.
> 
> https://photos.google.com/share/AF1...?key=OEZHX1BHX3VhOHJfR1NJV2VnM3MwcmwwdkIzWmJn
> 
> Let me know if the video doesn't work...
> 
> PZ



How much backlash are you seeing per axis?  I haven’t really fine tuned my setup yet but previously I had two thousandths backlash in all axis, .  I intend to pull apart the X end nut/ double bearing assembly ( what’s its name ? ) and see if it is assembled / designed correctly.  My hope is it isn’t so I can machine up new ones with a proper gap between two angular contact bearings.  I’ve heard of some cheap bearing blocks that don’t have any gap which negates the value of two angle contact bearings.  Fingers crossed...
Jake


----------



## phazertwo

I'm seeing about 0.0005".  At least that's what I measured the X and Z to be, and when I entered it into backlash comp it was dead on.  I can jog all over the place and it's always dead on.  I have a little more testing that I need to do to be sure, but I feel I'm 95% of the way there on those two axis.  Y axis is a whole different issue.

0.002" is quite a bit, I seem to remember that Acorn can only really handle 0.0015" compensation.  Take a lot of pics when you tear it down, I'd really like to see what it looks like.  I am willing to bet they leave a little to be desired, and re-engineering and machining them would be a fun project to upgrade the mill.

PZ


----------



## pburgh

Guys,
I came home to a prize.  My cylinder and valve for the power drawbar was delivered.  I've included a pic of them.  The one thing I'm concerned about is the weight.  The cylinder weighs 13.8 lbs.  I'll have to see what kind of affect it has on the z axis.  Thoughts? Take a look:


----------



## phazertwo

That thing is HUGE!  13.8lbs seems like a lot of weight to add to the Z axis, but I think you'll be fine, just slow it down a bit.  I think a slower Z would be well worth the power draw bar!  I'm very interested to see how this projects comes together, the time it takes to change a tool on these mills is defiantly painful.

If the Z works out to be too slow, you can always get a bigger Nema 34 stepper motor to drive the Z.  I'm pretty sure the stepper drives can drive a much larger motor.

PZ


----------



## pburgh

Well guys, I just went thru an exercise of frustration.  I finally fired everything up and the Acorn board didn't have a pulse.  Jake, I looked at the post that you sent earlier and tried a couple things.  I thought I had a bricked card.  But when I removed all of the connections but the power and the Ethernet cable and turned everything on, I got the blue pulse light and was able to communicate with the card.  I then went thru and set the leadshine config thinking that since it was still set to bench test that it might affect the board.  Once I hooked everything back up (and I double checked all of the connections) I turned it on and it did not respond.  So no pulse again.  It was getting cold in the garage so I came in.  Tomorrow is another day...  Fun times.


----------



## cut2cut

pburgh said:


> Well guys, I just went thru an exercise of frustration.  I finally fired everything up and the Acorn board didn't have a pulse.  Jake, I looked at the post that you sent earlier and tried a couple things.  I thought I had a bricked card.  But when I removed all of the connections but the power and the Ethernet cable and turned everything on, I got the blue pulse light and was able to communicate with the card.  I then went thru and set the leadshine config thinking that since it was still set to bench test that it might affect the board.  Once I hooked everything back up (and I double checked all of the connections) I turned it on and it did not respond.  So no pulse again.  It was getting cold in the garage so I came in.  Tomorrow is another day...  Fun times.



I would just connect one element at a time.  For instance just wire up the E stop.  Fire up Acorn and see if you still get a pulse.  Then add in the Limit switches.  Check for pulse, then home switches, and so on.  Until it stops giving you a pulse.  Even if items aren’t connected you should be able to do a custom setup and disable the items in the wizard.  It’s possible you don’t need to disable things in the wizard.  I’m. Not sure.  But just go one by one.  That should allow you to isolate the issue.


----------



## phazertwo

This is exactly what happened to me when I had the +24vdc in the wrong terminal on the input strip.  The way I found the problem was by disconnecting each one of the terminal strips except the power.  Then I re-connected them one at a time and connected to the Acorn through the Wizard.  Eventually I found that with the input strip plugged in that it wouldn't connect.  At that point it was easy to see that the +24vdc was in the wrong spot, moved it to the correct spot and she fired right up.  Good luck!

PZ


----------



## pburgh

Hey Guys,
I found the issue.  Now I have to find how to fix it.  It has to do with the VFD.  When I remove it from the setup the board works normally.  I wired it removing the original relays from the setup.  I used the second diagram that Jake provided above.  This also falls in line with a generic schematic that Centrioid provides with the Acorn schematics except they use the VFDCommon.  I have to dig into the plc on the vfd and see if there are any parameters that were set for mach and the nmotion board.  i'm suspecting the 2 speed control settings.  I have to see if there is a way to get a config page to see what's been set, or i'll have to go thru the different settings to see the value.  I also noticed that when I bumped my x, y and z that they were reverse.  there should be a setting in the wizard to reverse that.  Any suggestions would be appreciated.
Regards,
Doug


----------



## cut2cut

pburgh said:


> Hey Guys,
> I found the issue.  Now I have to find how to fix it.  It has to do with the VFD.  When I remove it from the setup the board works normally.  I wired it removing the original relays from the setup.  I used the second diagram that Jake provided above.  This also falls in line with a generic schematic that Centrioid provides with the Acorn schematics except they use the VFDCommon.  I have to dig into the plc on the vfd and see if there are any parameters that were set for mach and the nmotion board.  i'm suspecting the 2 speed control settings.  I have to see if there is a way to get a config page to see what's been set, or i'll have to go thru the different settings to see the value.  I also noticed that when I bumped my x, y and z that they were reverse.  there should be a setting in the wizard to reverse that.  Any suggestions would be appreciated.
> Regards,
> Doug



Hi Doug,
So you have 5 wires going  from the Acorn to the VFD and it’s causing the Acorn to not have a heart beat  ?
Jake


----------



## pburgh

Hey Jake,
Yes, that's right.  I haven't tried connecting the forward/reverse/common without the An_GND and AN_Out yet.  I've been looking thru the manual and online to see if I can find something that will help me understand the VFD a little better.


----------



## cut2cut

pburgh said:


> Hey Jake,
> Yes, that's right.  I haven't tried connecting the forward/reverse/common without the An_GND and AN_Out yet.  I've been looking thru the manual and online to see if I can find something that will help me understand the VFD a little better.



I thought Phazer also wired it without the relays ?


----------



## pburgh

I'm not sure if he used the configuration.  it should work.  I'm wondering if there is something programmed for the nmotion board that the Acorn doesn't like.


----------



## cut2cut

pburgh said:


> I'm not sure if he used the configuration.  it should work.  I'm wondering if there is something programmed for the nmotion board that the Acorn doesn't like.


Perhaps a post to the Acorn forum about the issue ?


----------



## phazertwo

cut2cut said:


> I thought Phazer also wired it without the relays ?



I did not... I was thinking I would leave them until I need a set of relays for something else.

The VFD seams to be programmed for MI1 = fwd, MI2 = Rev, and 0-10v for speed, so it "shouldn't" be any different.  If you think about it, all the relay is doing is tying DCM on the VFD to either MI1 or MI2 depending on which relay is engaged.  Shouldn't be any different than going to an output on the Acorn as long as the COM on the Acorn and the DCM on the VFD are tied together.

Pburgh, my next step would be to put a meter on continuity check between DCM on the VFD and any COM on the Acorn (I would actually check it to a few COM terminals on the Acorn) to make sure you have continuity between the digital COM on the Acorn and VFD.  Sounds to me that you have a strange ground loop that is causing this issue...

I just checked on my machine and the DCM on the VFD does not ring out the earth ground, however the Acorn ties earth ground to COM on the board (pretty standard for industrial stuff).  I wonder if the VFD needs the two separated...  You could try tying the second DCM on the VFD to ground and see if that helps out, but if the VFD needs them separate, we're stuck with relays.

PZ


----------



## pburgh

Hey Guys,
I just posted to the Acorn forum, so we'll see what they say.  PZ, i'll look into what you suggested, but i'm afraid that you may be right.  We may be stuck with the relays.  The generic schematic that is in the Acorn Schematic group shows using the Drive OK and reset features too.  I wonder if all of those settings need to be in place.  Also, looking at the manual, there are 2 switches one is set to PNP and the other is set to ACI, but we're connecting to AVI. Not sure if that has anything to do with it.  Let's see what the forum comes back with.
Thanks Guys


----------



## phazertwo

I thought I was actually going to make chips tonight... but it doesn't seem to be the case.  I programmed a simple-ish part to be made out of UHMW as a test.  I set the machine up and tried to run the program above the part in mid air, to make sure everything is rockin' before I start a real cut...

Well the thing just totally farts and gives up when I run the G-code.  It actually makes it thought the initial rapids, and tool change (not an actual change, but it says insert tool 1 and press cycle start), but as soon as it starts an actual "cut" X and Y start missing steps like crazy... like they barly even move. 

I'm running 125 IPM and 0.2s acceleration on both the X and Y axis, I can jog all over all day with no issues.  I'm only running 80 IPM in the G-Code.  I tried running it at 50% feed rate, but no dice.  It seems like it's not applying the correct acceleration while running the G-code...

I'm going to dink with it for another half hour and then make a post on the Centroid boards about it...

PZ


----------



## cut2cut

phazertwo said:


> I thought I was actually going to make chips tonight... but it doesn't seem to be the case.  I programmed a simple-ish part to be made out of UHMW as a test.  I set the machine up and tried to run the program above the part in mid air, to make sure everything is rockin' before I start a real cut...
> 
> Well the thing just totally farts and gives up when I run the G-code.  It actually makes it thought the initial rapids, and tool change (not an actual change, but it says insert tool 1 and press cycle start), but as soon as it starts an actual "cut" X and Y start missing steps like crazy... like they barly even move.
> 
> I'm running 125 IPM and 0.2s acceleration on both the X and Y axis, I can jog all over all day with no issues.  I'm only running 80 IPM in the G-Code.  I tried running it at 50% feed rate, but no dice.  It seems like it's not applying the correct acceleration while running the G-code...
> 
> I'm going to dink with it for another half hour and then make a post on the Centroid boards about it...
> 
> PZ


I am going to post a video soon of what I milled today  But the max Speed I have tried is in the 10 ipm range.  No issues that I can tell, with multiple tool changes too.  Look for a link to the video fairly soon

Btw,  with Linux CNC I could only get my x and y to run 70 IPS and about 50 IPS on the Z before I lost steps.  If memory serves correct... foggy memory however.  It didn’t bother me as i’m not pushing anything hard because I don’t have many carbide bits... yet


----------



## cut2cut




----------



## pburgh

Very cool Jake, so that's what it looks like when it runs.  I like your chip guard.  how did you attach it to the table?


----------



## pburgh

Guys,
Are you using the ENA terminals?  Do you think that the drives have to be reconfigured for the motors?  I wonder if some of the dip switches have to be changed.  Did you get a manual for the drives for your mills?  I didn't.
Regards, 
Doug


----------



## phazertwo

I got mine running, and at full blast!!





Was running a few different tool paths to really test it out, including some adaptive paths.  I noticed that the code to run this (all one tool) was almost 14k lines of code!  So in CNC12 I went into config - smoothing, and selected precision mill.  Dry ran the code and BOOM no more problems!

After that I went back to fusion and looked at the points in the tool path... there was A LOT, and in the adaptive they were very close together which I believe was the cause of my issue.  So I changed the smoothing in the adaptives to 0.001" instead of 0.0004" which reduced the code to ~6k lines and added just a bit of space between the points.  Then I ran the part and it ran smooth as hot butter!

I am stoked that it ran, and it ran well, but I could only really claim ±0.010" which is pretty terrible.  However this is UHMW with a really cheap end mill that has been used on aluminum quite a bit, and I really need to review the CAM to make sure I didn't accidentally leave radial stock or something.  I need to run some more stable material with a better tool before I cry too much.

PZ


----------



## cut2cut

pburgh said:


> Very cool Jake, so that's what it looks like when it runs.  I like your chip guard.  how did you attach it to the table?



I added some brackets using existing threaded holes or tapped new ones into the table.  Everything is just temporary... but since the mill is shaping up I'll redo things properly.  I tend to do that...just get things up and running then work backwards and redo things properly over time.  lol


----------



## cut2cut

phazertwo said:


> I got mine running, and at full blast!!
> 
> View attachment 255234
> 
> 
> Was running a few different tool paths to really test it out, including some adaptive paths.  I noticed that the code to run this (all one tool) was almost 14k lines of code!  So in CNC12 I went into config - smoothing, and selected precision mill.  Dry ran the code and BOOM no more problems!
> 
> After that I went back to fusion and looked at the points in the tool path... there was A LOT, and in the adaptive they were very close togetherwhich I believe was the cause of my issue.  So I changed the smoothing in the adaptives to 0.001" instead of 0.0004" which reduced the code to ~6k lines and added just a bit of space between the points.  Then I ran it and hot  it ran smooth as hot butter!
> 
> I am stoked that it ran, and it ran well, but I could only really claim ±0.010" which is pretty terrible.  However this is UHMW with a really cheap end mill that has been used on aluminum quite a bit, and I really need to review the CAM to make sure I didn't accidentally leave radial stock or something.  I need to run some more stable material with a better tool before I cry too much.
> 
> PZ



Thats awesome !  I'll read up on the smoothing in cnc12 now.    Looks great.  

Yeah,  often fusion seems to leave stock by default... I think.  I need to be more diligent noticing that setting too.   Using better bits is always best, but in this "test mode" we are in, its hard to use the good stuff.  But the end mills / etc are where the rubber meets the road, so to speak !  

Jake


----------



## pburgh

Looking good guys.  Glad to hear things are starting to pick up.  I'm waiting for Marty to get back to me on the VFD.  I'd like to try to get this working like it should, but I might have to go back and put the relays back in play.  We'll see.


----------



## pburgh

cut2cut said:


> Hey Doug,
> 
> Here is the schematic you'll want to use if you keep the relays.  However, to keep it simple and not create unwanted noise you should really just run two new shielded wires from the Acorn directly to the VFD for the ( without going through the terminal block ).  AN_OUT on the Acorn to AVI on the VFD.  And AN_GND from the Acorn to the ACM on the VFD.
> 
> Then for the M1, M2 and DCM on the VFD use the rest of the wiring diagram enclosed ( if you intend to keep using the relays ).
> Note, the lower right corner shows the KA1 and KA2 terminals ( 1,5,9, 13 and 14 ).  I believe your 029 and 031 are identical to the wiring used in my mill, specific to the VFD anyway..... so this schematic should work for you as well.  Note, you may have to rewire your relay, possibly,  but hopefully not !   I can't say because I previously changed mine to wire for the Mesa 7i76e / LinuxCnc.
> Let me know if you have any more questions.
> 
> Jake
> View attachment 254762





Jake,
I'm getting frustrated waiting to hear how to set this up without the relays.  I think i'm going to put the relays back in play.  One question on the diagram above.  You have Gnd  on the power supply going to Com on the Acorn.  Is that the earth ground or the Com on the power supply?
Thanks,
Doug


----------



## cut2cut

pburgh said:


> Jake,
> I'm getting frustrated waiting to hear how to set this up without the relays.  I think i'm going to put the relays back in play.  One question on the diagram above.  You have Gnd  on the power supply going to Com on the Acorn.  Is that the earth ground or the Com on the power supply?
> Thanks,
> Doug



I'll go double check now.. expect a response in the next half hour


----------



## cut2cut

pburgh said:


> Jake,
> I'm getting frustrated waiting to hear how to set this up without the relays.  I think i'm going to put the relays back in play.  One question on the diagram above.  You have Gnd  on the power supply going to Com on the Acorn.  Is that the earth ground or the Com on the power supply?
> Thanks,
> Doug



The acorn COM between Oc4 and Oc5 is connected to the 24v power supplies COM ( between V1 and V2 )


----------



## cut2cut

Additionally here are two pictures of my current wiring of the relays and VFD

Hope that helps you get to the promised land.  Sorry about steering you towards removing the relays.  It seemed to be easier but ended up being the long road !


----------



## pburgh

Thanks Jake,   no problem.  I'd like to get it working without the relays if possible, but I don't know if i'm getting them to understand on the Centroid forum. that this was setup already on another controller.  It makes sense, but  I think there is a voltage needed to feed the m1 and m2 terminals.  I'm not sure though.  This is my first time working with a device like this and I want to be sure that I don't smoke it.  Some other configurations I've seen online use the relays  It's interesting that the coil voltage is used in the circuit on the traditional way.  I wish the manuals were written better for these.  Seems the only way to understand these is to noodle around with them or have someone give you a rundown on them.    I'll let you know how I make out.
Thanks again,
Doug


----------



## phazertwo

pburgh said:


> Guys,
> Are you using the ENA terminals?  Do you think that the drives have to be reconfigured for the motors?  I wonder if some of the dip switches have to be changed.  Did you get a manual for the drives for your mills?  I didn't.
> Regards,
> Doug



Sorry I just realized I missed this.  Yes I WAS using the ENA terminals, however if there is an e-stop condition than the Acorn will shut the drive down and the motors de-energize so they are very easy to move and lose position.  So I just unplugged the ENA terminal strip from the drives.  I did have to do some funky stuff in the advanced axis configuration in the wizard but I cannot remember what it was.  Let me know if you need it and I will try to get it for you tomorrow.

Hopefully you can get her choochin' with the relays!  Once you get it up and running it's going to feel like a whole new mill, at least mine does.  I ran that plastic part at 0.004" ipt which was 52 ipm, and she was fast and smooth.  With a 70% step over at that speed the motor wasn't super happy, but it did it!  Might be upgrading to the AC bearings and belt drive like Jake has sooner than I anticipated!

PZ


----------



## pburgh

Well Guys,
I got it to run with the relays back in place.  Still haven't been able to check the spindle.  Now I have an issue with an e-stop.  I think it's one of the limits.  To tired to run that down tonight.  Hopefully i'll see that tomorrow.
Regards,
Doug


----------



## cut2cut

pburgh said:


> Well Guys,
> I got it to run with the relays back in place.  Still haven't been able to check the spindle.  Now I have an issue with an e-stop.  I think it's one of the limits.  To tired to run that down tonight.  Hopefully i'll see that tomorrow.
> Regards,
> Doug



Did you remember to bring 24v into the IN circuit ?

If your estop is mostly NOT working but works a little bit on restart of the program its most likely because you haven't supplied 24v to that part of the card.


----------



## pburgh

Yes, I have the 24v feed above input 4.  This is weird, I was jogging all of the axes this afternoon waiting for an answer about the VFD and they all worked as I expected, except where I had to move or adjust the dog for the home limits.  The x,y and z limits all worked and jogged as they should, but when I started the program after I reintroduced the relays, and went to home everything it went into a estop fault.  Weird...  I was too tired by that time to dig into it.  I'll figure it out tomorrow.  This has been more painful than I imagined.  Although it gets me back into thinking motor control.  it's been a long time since I noodled with something like this.  Over 20 years.  Oh by the way, your 97 and 99 are different than mine because I think they switched them for rotation.  I'll verify that tomorrow.  Almost time to head to bed.  I was just looking for a potential drawbar online to replace the one that comes with the machine.  When I add the Bellville washers and tophat I think the original will be that much too short.  Not sure where i'll get one, but I have a lot of the other things coming to start that project.  I need to get the mill running so I can make the parts for it.  That ought to be fun since I've never milled anything before.  But you have to start somewhere....
Regards,
Doug


----------



## phazertwo

Sounds like you are hitting you're limit before hitting your home switch...

How did you wire the limits?  I didn't bother with my limits because I couldn't (easily) wire them in series with the e-stop, something I hope to correct later.

PZ


----------



## pburgh

Yeah i'm going to have to adjust the dogs for the limits.  What I don't understand is that before I had the VFD running, they all worked with the jog switch and were acting as I would suspect.  But now I have a fault somewhere that's not as obvious.   I followed the schematic that Orin on the Centroid site drew up.  That follows the Centroid schematic.  http://centroidcncforum.com/viewtopic.php?f=60&t=1270#p6959 
 I switched all of the contacts on the limits to NC and added a new NC e-stop switch and a NO Jog switch that I mounted on the side of the swing-arm control box.  Then I proceeded to series the wires from the x,y and z limit switches and it all tested out fine.  I'll draw up a pic on the wire colors and numbers.  Although our mills will probably differ in that respect. 
Question:  from the mill table standpoint, where is the best place to position the home dogs?  Right before the limit or further away?

Regards,
Doug


----------



## pburgh

Oh, one other thing  I wanted to ask you guys about.  I'm a newb on machining.  For the power drawbar, what type of aluminum should I use for the base 6160 or something different?  Also, i'll need to get a custom drawbar.  Any suggestions?
Thanks,
Doug


----------



## phazertwo

pburgh said:


> Yeah i'm going to have to adjust the dogs for the limits.  What I don't understand is that before I had the VFD running, they all worked with the jog switch and were acting as I would suspect.  But now I have a fault somewhere that's not as obvious.   I followed the schematic that Orin on the Centroid site drew up.  That follows the Centroid schematic.  http://centroidcncforum.com/viewtopic.php?f=60&t=1270#p6959
> I switched all of the contacts on the limits to NC and added a new NC e-stop switch and a NO Jog switch that I mounted on the side of the swing-arm control box.  Then I proceeded to series the wires from the x,y and z limit switches and it all tested out fine.  I'll draw up a pic on the wire colors and numbers.  Although our mills will probably differ in that respect.
> Question:  from the mill table standpoint, where is the best place to position the home dogs?  Right before the limit or further away?
> 
> Regards,
> Doug



Interesting... I'm not a fan of the jog off limits option, seems like too much of a chance to mess something up.  Anyway, I would pull the wires for the VFD and see if it works as it did before.  That will at least tell you if it's the VFD wiring that is causing the issue and hopefully keep you moving in the right direction.

Also, I'd agree with Marty, the VFD probably just needs to do it's own thing.



pburgh said:


> Oh, one other thing  I wanted to ask you guys about.  I'm a newb on machining.  For the power drawbar, what type of aluminum should I use for the base 6160 or something different?  Also, i'll need to get a custom drawbar.  Any suggestions?
> Thanks,
> Doug



I'd use 6061 T-6, at ~37 ksi yield strength its right about as strong as A36 steel.  Should be plenty strong, depending on the design of course, I'd be happy to take a look at a model and review it (and steal it) 

As for the draw bar, your best bet is probably to design it and see if you can get someone on the board here to make it for you with a lathe.

PZ


----------



## pburgh

Hey Guys,
I'll post pics of my limits here In a bit.  I wanted to get your feedback of how yours are wired.  I know they are NO, but  I moved mine to NC staying with the same switch location just swapping NO for NC.    PZ, thanks for the info on the aluminum, and absolutely i'll share what I come up with and even take suggestions to make this thing awesome.
Doug


----------



## pburgh

Hey Guys,
Here are the pics of the limits:
On the X: Blue is OV and Yellow is 88
On the Y: Black is OV and Gray is 89
On the Z: Blue is OV and Black is 90
One thing is consistent is that things are not consistent.
Y and Z are on what i'll call the bottom switch and X is on the top switch.
OV is on the right on X and Y and on the left on Z.
I'm going to attempt to make them the same.  Depending on how the switches make and break this could make a difference.
I've also attached the schematic on how I connected the wiring for the limits.  Where you see the color transition are the conductors coming together on the terminal block.  Again they didn't stay consistent, so there are some mismatched colors.  I hope this helps.  Please let me know if you have any questions or suggestions.  I think this may clear up my issue.
Regards,
Doug


----------



## phazertwo

Your wire numbers are very different than mine.  I cant't really tell what is going on in the pics, however the diagram makes perfect sense.  If it's actually wired like that it "should" work.

Have you removed the limit switches from the equation to see if you can get it to fire up.

PZ


----------



## pburgh

Hey PZ,
it does work now.  It goes into a fault when I try home the machine at the start.  And then I can't move any axis. I have to turn everything off and move the axis manually.  I'm checking to make sure that I have the machine setup to home properly.  I also have to go over the limits again and make sure they are engaging correctly for this configuration to work.  One of the switches is set with the conductors in reverse of the other 2.  if the make/break is equal on both contacts, then it shouldn't matter. But if contact hinges, then there might be a problem.  I don't want to take too much apart to determine that.  I'll get it figured out, but it's frustrating that this thing wasn't put together more consistently.  BTW, if you are having any intermittent issues with something not working 100% of the time, you might have a loose crimp on one of the crimp sleves they use.  I found 2 when I was rewiring the VFD for conductors 97 and 99.  They both literally fell off.  So I had to redo the crimps with  new sleeves

Doug.


----------



## phazertwo

I was thinking if you disconnect the limit switches, and leave the home switches, then try to home you might be able to narrow the problem down.  If you have the same problem with the limits disconnected than your problem is probably with the home switches.  Just a trouble shooting technique.

I had the same issues with loose connections from the start (x axis would drop out right out of the box).  I got tired of it and did a pull test on every wire, and probably 90% of them were loose, as in with a light tug the would come out of there terminal.

PZ


----------



## cut2cut

phazertwo said:


> I was thinking if you disconnect the limit switches, and leave the home switches, then try to home you might be able to narrow the problem down.  If you have the same problem with the limits disconnected than your problem is probably with the home switches.  Just a trouble shooting technique.
> 
> I had the same issues with loose connections from the start (x axis would drop out right out of the box).  I got tired of it and did a pull test on every wire, and probably 90% of them were loose, as in with a light tug the would come out of there terminal.
> 
> PZ



Sigh.... It’s probsbly why they wired it NO.  So it wouldn’t fault before it left the factory test.  It’s sad but it’s been said before,  you basically have to tear these mills down to the bare bones or you’ll have surprises like this, mostly lacking in hidden workmanship.  

It’s good iron and mostly good components. A good base to work from but it needs to treated as though it wasn’t put together with tons of care, imho.


----------



## phazertwo

cut2cut said:


> Sigh.... It’s probsbly why they wired it NO.  So it wouldn’t fault before it left the factory test.  It’s sad but it’s been said before,  you basically have to tear these mills down to the bare bones or you’ll have surprises like this, mostly lacking in hidden workmanship.
> 
> It’s good iron and mostly good components. A good base to work from but it needs to treated as though it wasn’t put together with tons of care, imho.



I think you're probably right about the NO.  I also agree about the good iron and components.  Machine it's self is quite nice IMO, and the only gripe I have with the controls (besides the nMotion , but we don't need to talk about that) is that they are 24vac not vdc, other than that it's just been workmanship issues.  Honestly for the price... I can tinker with it.  No buyers remorse at all, if I wanted a perfect machine I would have saved longer and bought a PCNC1100, but than I wouldn't know nearly as much as I do now about CNC!

PZ


----------



## pburgh

Guys, you are both right on.  I was telling my wife that if I had CNC'd this thing myself, I'd know it worked right and I'd have learned the ins and outs as I went.  This is a little more frustrating because you have to back into it.  And without documentation and it being Chinese, it makes it more difficult.  I want to thank both of you for your help and support in this.  I got very little info with this mill.  On another note, I was reconnecting a couple of the limits and one of the forked ends came off of one of the wires.  So that may have contributed to part of the issue.  I almost hate to dig in too far because i'll eventually have the whole thing reconstructed which is what I was trying to avoid.  But i'll continue to troubleshoot tonight and hopefully get somewhere.  A couple of other questions.  Where are the dogs set for your home limits?  As your facing the limits, mine is on the right top on the X, the left top for the Y and the top front for the Z.  Then the hard limits are set at either end on the bottom for each axis.
My other question is, did you get a manual with the oiler?  or is there a way to cut back on the amount of oil that it disperses?  I have to keep cleaning up the puddles that collect in the chip tray.  Sorry to be so long winded...

Thanks,
Doug


----------



## phazertwo

My home switches dogs sound like they are in the same location as yours.  My dogs we also loose, so check on that, the could be sliding back.  I also had wires break in the horse shoe terminals... They're consistent if nothing else!

I don't remember if I have a manual for the oilier, but I defiantly had to turn it down.  I just pulled the wires out of the terminal block while I was tuning, it was just a waste of oil.  I'd be interested to see how the Acorn controls the oilier, maybe based off of inches traveled instead of time?

PZ


----------



## cut2cut

No problem Doug,  happy to try help.... but its tough to help from afar and obviously things went sideways with the idea of removing the relays.   a curve ball.   Just try to put that behind you and keep at it.  Things will pick up for the positive... just a little hurdle...

So,  here is my homing setup just for reference :

I believe I moved my home limit stop positions  from the way it shipped.    This all may be something you know already, but I figure if not, its good for me to go through it again to further engrain.

My homing sequence is Z , Y , X
If I’m sitting left of the center facing the mill, the head moves up when homing Z ( towards zero in a positive direction ) .   When homing Y the “saddle” moves away (toward the column/  towards zero in a negative direction ) .  And when homing X the table moves away too ( towards zero in a negative direction ) .   All while I’m sitting left of center facing the mill.
So Z is the only “odd” direction but its best ( in practice / use )  if the Z moves up and away to home rather than down which could quite possibly crash if you have a tool holder in the spindle.  I believe the nMotion actually had Z try home going toward the table, if you can believe that !  I've tried to erase that memory, however  

In this setup my fixed HOME stops are located up toward the top of the fixed Z column.  Near me ( sitting left of center ) for the Y ( attached to the base ). And Near me ( sitting left of center )  for the X ( the home limit stop is attached to the Y “saddle” )

The best way to think about "positive and negative" in the DRO is :    the cutter is the reference.  So when the X axis is moving right to left  the CUTTER / END MILL is “moving *relatively speaking* from left to right ( *relative* because the cutter isn’t actually moving at all ).  In this scenario, the X axis DRO is moving in the positive.   Same is true of the Y axis,  In other words, If the table is moving back to front ( the  Y “Saddle” ) , the relative movement of the cutter/end mill is moving from close to you to the back ( if you were actually sitting on the table and moving with it ).. so the end mill is (relatively speaking ) moving in the positive direction, so the DRO increments the number in the positive direction.

Z , the cutter actually moves with the head.  So its sort of backwards to what the X and Y do.  So when the cutter moves up, its going positive, and when it moves down….  you guessed it… negative !  lol   So,  every move toward your work piece in the Z axis is negative.

Hope I got all that right !

Jake


----------



## pburgh

Thanks Jake for the explanation.  That makes total sense.  I didn't understand that the cutter was the reference for +- X,Y and not the table.  I was watching a video that Marty made and was confused when he was referring to the table moving in a negative direction to the right.  Then i read it in the manual and had an aha moment.  Pays to read the manual.  That one's on me.  I have to change the X home to the left.  it was originally set to the right.  
I'm actually catching a glad right now.  I finally got this thing to work.  My issues were caused by them and me.  By them not making sure that everything was crimped fastened down secure and consistent, and by me for not noticing the Y home wasn't hitting the dog.  The bolts holding the limit were loose.  as well as the switches having inconsistent orientation.  I like the limits they used and the way they are easy to adjust.  I don't like that you can't easily see the orientation and don't know if mechanically they are working the same.  When you are putting things in series it matters.  Plus i'm partially handicapped, so I can't get down to where the y limit is located very easily.  I don't want to use that as an excuse though.  I should have been checking that a little closer.  But, once I got it homed, I was able to fire up the spindle and check it out, so i'm moving in a positive direction.  Now i'm going to switch gears a bit and see if I can get the metal I need for the power draw bar.  And hopefully i'll be cutting some stuff this weekend if all goes well.  I'll keep you all posted.  It's been an adventure gathering all of the little parts for this thing.  I wanted to try to get that going because I can't reach the top of the spindle to change out the collets very easily.  Plus I invested in the Tormach quick change system so I want to start using that.  I have a lot to learn, but hopefully it will be fun and interesting.

Regards,
Doug


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## cut2cut

Great to hear it’s starting to come together.  Go make some chips !!! ;-)  I’m finally starting to loosen up and not hover over the E-stop as much.  This is mostly due to the Acorn, I think.  But I do need to go over the connections a bit more myself and wire up the switches as NC asap.  Fingers crossed but I think the person doing the crimps on mine was doing a good job!   
Can’t wait to here more about the power drawbar as that is really something that will help me too. I might just go ahead and order it but it starts off a chain reaction.  I’ll need a compressor,  which will need to be in an sound proof box ( I hate extraneous noise ).  I also worry the extra weight of the drawbar cylinder components might tax the 1200 oz Z stepper motor.  The hope is to someday use a more powerful, but also servo motor,  for the Z axis.  I need to research how they maintain the Z at height when it’s all turned off.  It must have a brake , but what if there is a power loss ?   Certainly a good and rewarding project.  Having fun, so it’s a good journey.   Thanks for all your help too guys.  Much appreciated.
Cheers,
Jake


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## pburgh

I was looking at a bigger motor last night.  In a NEMA 34 the biggest Leadshine has is a 1699, I think.  I didn't see if it would work with the drive we have though.  I need to dig into that.  Something else is happening that I didn't mention.  Every once in a while the breaker for the drives trips, so I 'm suspecting either a broken terminal or the breaker is undersized.  I wanted to enjoy the victory before I jump into that.  This thing is probably going to add another 18 to 20 lbs to the head.  I'm trying to build most of it out of aluminum.  I just picked up some at the supply house.   Now I have to start designing the layout.  I'll keep you guys posted.
Regards,
Doug


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## phazertwo

Glad to hear that it's running pburgh!  Hopefully you can make some chips this weekend!  Seems weird that the breaker keeps popping... Do you know what the breaker is rated for? I'll look at mine when I get then we can compare.

Jake, are you sure you have a 1200 oz-in motor on the Z?  Mine came with 900 oz-in on the Z and 600 oz-in on the X and Y.  I've been toying with the idea of getting a bigger stepper for now, but you're right, the true fix is a servo.  Even the little DMM DYN2's would be a huge improvement just because they are constant torque though out their RPM range.

So I have been machining a bunch of UHMW for testing, and I am very comfortable with the machine/control so I don't need to stick around except to blow chips out (need to install my mist coolant).  However i'd be lucky to hit ±0.020", it's really bad.  Even with Mach 3 and minimal tuning, i was ±0.005".  How are you doing in the accuracy department Jake? 

PZ


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## cut2cut

The original "spec / quote " I got says 1200 OZ stepper on the Z axis but it might have shipped with less, which would be a bummer.  I'll check what the model number is on the actual Z stepper and reply later.





As far as accuracy, I am going to be putting in the new AC bearings in the X, Y and Z axis,  then I'll fine tune the steps to get correct steps per inch. 
Basically, I haven't tested it for accuracy, sorry.   However,  how many IPM are you pushing it ?   I only ask because you might be missing steps due to pushing those "little" steppers too fast ?
Also, I would really suggest looking into those end bearing blocks as I have and freeing up the other end ( lose the hand wheels and anything pinching the screw end ).  Only then will you know if you are getting true ball screw backlash compared to binding due to the two ends pulling against the ball screws themselves.  If that is occurring, I believe you could prematurely wear out your ball screw.  Just something to think about.  It really doesn't take long to dig into the X axis to inspect if the AC bearings inner races are hitting each other.  However you'll need a press to put a washer in between the outer race to really fix it, if needed....


----------



## phazertwo

I just dug up my quote, and it says the same thing... dumb dumb...

I 'm pushing it at 125ipm, and I really don't think I'm missing any steps.  When I return to zero at the end of a part it's right were it started.

Also, if you miss steps at higher speed, i'm pretty sure it's all over but the crying.  A missed step means that the motor output was actually stopped for a fraction of a second, but the drive keeps driving like it never stopped, so the motor now has to accelerate to that speed instantly.  Every time I have missed a step, it's been very clear, and which ever axis misses the steps gets shifted for the rest of the run... makes for a very funny looking part.

That being said, I'm sure that it's possible to miss a step here and there and not notice, but I bet it's pretty rare.  One of the DMM servos with a out put that can tell the acorn when it's off position is the way to go!  Marty is doing a build on a router like that currently, I'm patiently watching that to see how it turns out.

PZ


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## cut2cut

86HS85 Z stepper is indeed what is on my mill.  It’s 1200oz.
This weekend i’ll mill some circles and squares at various ipm ( with proper speed/feed rates) to check accuracy...


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## TomS

I've been watching your thread daily and am enjoying the progress you are making.  Thanks for the education.

For info you can get a NEMA 42 4200 oz in stepper for your Z axis.  It's what I'm running on my PM-932 and it moves the head up and down like it's not even there.  I also haven't had any issue with the Z axis creeping down when it's powered down.  

I have 1600 oz in steppers on the X and Y.  I can't remember a job where I missed steps.  But I can say I've snapped off a few end mills and the mill didn't grunt a bit.

Good luck with your projects.


----------



## cut2cut

Guys,  just a note about the stepper shaft size if you haven't noticed already.   At least on my mill, and presumably yours, the nema 34 stepper motors have 14mm shafts.  ( note the model number for the Z :  86HS85-14 ).  So if we ever replace the existing with a bigger one, or servos, etc, we'll probably need to get new couplers ( lovejoy or other ). Not sure if 14mm is very standard at this point ?

p.s.  I changed out my bearings in the Y axis last night and added a shim between them.   I still have .0014 of backlash in the Y but my X has only .0004 which is nice.  Someday I might get a new Y ballscrew or maybe have this one repacked with bigger balls.

oh,  and thanks Tom !

Jake


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## phazertwo

Thanks Tom!  I actually remember reading your build when I was toying with the idea of getting a manual machine and doing the conversion myself...  In the end the lack of time won out, and I purchased this mill.  Anyway your mill is pretty much my end goal...

I ran my first aluminum part with the Acorn yesterday.  I made no changes to my motor tuning before I ran it and it came out ±0.0005"!  This is according to measuring with my very nice Mitutoyo calipers... so I can only really claim ±0.001" but I'll take it!  The ONLY thing I did different is I setup a new tool, so I'm wondering if I have a offset set wrong on the other tools...  Again it was just a dinky little test part that was purely for testing accuracy and S&F for finish... it came out BEAUTIFUL!  Only issue I have now is tram, looks like I'm going to have to shim my column a bit.  Not looking forward to that.

Now that Jake got his new AC bearings installed, I think I'm going to tear open mine and see what it looks like as well.  I'm a little worried that I am pre-maturely wearing the lead-screw after his comments.

Anyone have any good info on how to adjust the gibs?

PZ


----------



## cut2cut

phazertwo said:


> Now that Jake got his new AC bearings installed, I think I'm going to tear open mine and see what it looks like as well.  I'm a little worried that I am pre-maturely wearing the lead-screw after his comments.
> 
> Anyone have any good info on how to adjust the gibs?
> 
> PZ



Just make sure you have the shims on hand before you tear it down unless you don't mind doing it twice.    You can probably reuse the existing bearings though, instead of buying new.

Thats awesome to hear.  You had me worried before regarding the lack of tolerance.  How fast were you cutting ?  IPM ?
Late last night I made a circle and square and came out .001 shy of my goal so its likely I need to measure the end mill. so far so good.
Sorry, nothing helpful to say about gib adjustment.  I fear its something that requires feel ( experience ).  Hopefully someone can chime in with something !

Jake


----------



## cut2cut

Regarding Gib adjustment, I ran across NyCNC’s youtube from yesterday. He mentions they are doing a maintenance tear down of their Tormac 1100 and will be posting a video that will include gib adjustment . . Good timing !


Sent from my iPhone using Tapatalk


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## phazertwo

I watched a maintenance vid from him yesterday as well, it had some good info on adjusting the gibs.  This one was shot in 2015.





BTW the speeds and feeds section of NYCCNC.com has made me a better machinist, no question.


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## phazertwo

Spent most of yesterday working on the mill.  It was bugging me that I was only getting 40 ipm out of the Z, even though the spec on the quote from PM was 75ipm.  So I started digging into it and the X,Y,Z drives were all set identically, even thought he Z is a 1200 oz-in and the X and Y are 640 oz-in.  Looks like the Z can run 1 row higher on the amperage table (according to the specs from Leadshines website), so I configured the dip switches accordingly and started testing.  I was able to get 75 ipm with out missing steps (just jogging around) however it sounded like hell, which made me remember a post from Jake about removing the manual Z.  I decided there is no time like the present and I pulled the electrical panel off the column and removed the pinion from the manual Z and did some more testing.  WHOOLY SMOOTH!  The Z has always been noisy and clunky, now it's smooth as butter and running 75 ipm!

Made this test part as another validation.  Everything is ±0.002, with most operations in the y being ±0.001 so I might need to re-tune the X.  Tried to use more tools that I haven't used with the Acorn yet, so I used the Super Fly to bring the top down (though I didn't come down far enough, as shown by the tool marks down the center from the original scrap part), roughing end mill to hog everything out aggressively, drilled a hole down the center, and used the chamfer tool to deburr.  Everything ran flawlessly.






LOVING the Acorn.  I'm ready to make my first useful part, which will be a cover plate to replace the bearing cover for the manual Z.

PZ


----------



## cut2cut

Thats awesome PZ,   the part looks great.    Yeah,  I'm really liking the Acorn too.   My Z is still a bit noisy but hugely better than when I had the manual crank connected.   I intend to dig into it, but my Z ball screw seems to be miss-aligned or bent.    Someday I'll get into that but until then, I have other projects, like rigid tapping. 

Not sure you guys saw Marty's video on the cheap Omron encoder.  It works ok so far and its only $25.  The supplied coupler is just barely adequate and will probably result in failed encoder bearings.  It can handle 5000 rpm max so it should be adequate for most jobs.  Currently I've rigged mine up so I can see if I can do rigid tapping.  Too early to say if I have my VFD setup properly as I need some proper sized bits for my test tap.  I'll report my results.  Likely I'll use a hybrid most of the time, with a compression/tension tap head and the encoder to give the tension head the least amount of "work" possible, so it won't be truly rigid tapping but only because it should produce the results I want.

If you can sometime, please share a picture of the dip switch settings for the Z drive.  I'd like to push mine a bit more so it won't loose steps as easily.

Cheers,

Jake


----------



## aolney

Thanks for the tip about the vfd preventing the acorn from turning on. It's been driving me crazy to have it fail at random. Turned off the vfd and it powered right up.
Thanks again,
Andy


----------



## cut2cut

aolney said:


> Thanks for the tip about the vfd preventing the acorn from turning on. It's been driving me crazy to have it fail at random. Turned off the vfd and it powered right up.
> Thanks again,
> Andy



Looks like we are near each other !  I live in Seattle.  

Mine has been randomly not firing up as well.  I'll have to make note of that when I fire up the computer the next time !

Jake


----------



## aolney

cut2cut said:


> Looks like we are near each other !  I live in Seattle.
> 
> Mine has been randomly not firing up as well.  I'll have to make note of that when I fire up the computer the next time !
> 
> Jake


Yes, I am over in Port Townsend, just moved from Sammamish. Andy


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## phazertwo

I don't suppose anyone has started modeling the head of the 940 in Fusion?  After doing about 50 tool changes yesterday... I'm ready for a power draw bar.

PZ


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## phazertwo

Sorry it took so long, but here are my current settings for the Z and Y axis.  X is set identical to the Y.




I did have a strange situation where I missed steps on Sunday, not sure what caused it but the Y just didn't go.  It really messed up the part, which was a huge bummer, so I backed off on the speed and acceleration.

My current settings:
X & Y set to 100IPM and 0.3s accel
Z set to 60 IPM and 0.3s accel

I feel like these are a touch conservative, but after messing that part up I decided it's better to move a bit slower and get it done right.

PZ


----------



## cut2cut

phazertwo said:


> Sorry it took so long, but here are my current settings for the Z and Y axis.  X is set identical to the Y.
> 
> View attachment 257093
> 
> 
> I did have a strange situation where I missed steps on Sunday, not sure what caused it but the Y just didn't go.  It really messed up the part, which was a huge bummer, so I backed off on the speed and acceleration.
> 
> My current settings:
> X & Y set to 100IPM and 0.3s accel
> Z set to 60 IPM and 0.3s accel
> 
> I feel like these are a touch conservative, but after messing that part up I decided it's better to move a bit slower and get it done right.
> 
> PZ



Holy cow Batman.  100ipn.  Assuming that’s just rapids .  What Speed are you cutting at usually ?


----------



## phazertwo

Yeah, 100 IPM is max speed.  I seem to spend a lot of time between 15 and 25IPM cutting, but it all depends, I have hit 39IPM roughing aluminum.

I've just been running everything at full spindle speed and then setting the IPT to 0.001 or 0.002 depending on roughing or finishing.  I got this set of  carbide end mills and they have been awesome.  I used the 6mm to do 8 0.825" holes in a 0.5" steel part, and it's still in great shape.

https://www.amazon.com/gp/product/B01M0W9XON/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

And I have been using this to rough out aluminum.

https://www.amazon.com/gp/product/B01AOE7DBU/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

That rougher loves to plow through aluminum, I have really been pushing it to see what it can do and I honestly can't believe it still in as good of shape as it is.  I have had to use a small punch and hammer to clear aluminum from it more than once, but it still looks sharp and cuts like new.

I'm working on a S&F spread sheet I'll share once I get it a little more nailed down.  I'm going to include links to all of the tools I bought online (mostly amazon).

PZ


----------



## cut2cut

phazertwo said:


> Yeah, 100 IPM is max speed. I seem to spend a lot of time between 15 and 25IPM cutting, but it all depends, I have hit 39IPM roughing aluminum.
> 
> I've just been running everything at full spindle speed and then setting the IPT to 0.001 or 0.002 depending on roughing or finishing. I got this set of carbide end mills and they have been awesome. I used the 6mm to do 8 0.825" holes in a 0.5" steel part, and it's still in great shape.
> 
> https://www.amazon.com/gp/product/B01M0W9XON/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
> 
> And I have been using this to rough out aluminum.
> 
> https://www.amazon.com/gp/product/B01AOE7DBU/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
> 
> That rougher loves to plow through aluminum, I have really been pushing it to see what it can do and I honestly can't believe it still in as good of shape as it is. I have had to use a small punch and hammer to clear aluminum from it more than once, but it still looks sharp and cuts like new.
> 
> I'm working on a S&F spread sheet I'll share once I get it a little more nailed down. I'm going to include links to all of the tools I bought online (mostly amazon).
> 
> PZ



Thanks for the end mill suggestions and also the stepper drive settings. , I’ll give them all a try. Looks like you are enjoying yourself!

Was busy yesterday evening wiring up the VFD I’ve had sitting around collecting dust. It has a feedback card to take advantage of the spindle motors encoder to maintain better torque and rpm. Also implementing a brake resistor. It’s all to be able to rigid tap. Fast acceleration and deceleration are required. It’s just one of those goals, I gotta be able to tap easily and consistently , even if it’s with a compression / tension tapping head, I need it ! Lol I really should be focusing on the power draw bar though, but almost everything needs threads, right ! Lol. I should order up that cylinder Doug suggested. I just don’t really want to have a compressor running all the time. Noise.... lol. Going to have to build a sound proof box for it, I guess ! Totally worth it though , to have a power draw bar. 

Jake 


Sent from my iPhone using Tapatalk


----------



## phazertwo

I hear you on the rigid taping, it would be super nice.  I'm going to attempt some thread milling, the tooling is expensive, and its a much slower operation (at least with single point) but I mostly am going to need 3/8-16 and 1/4-20 threads, and If I get the two tread mills that can do that I think I'm out ~$140.  With those two mills I should be able to do anything with a 14-56 TPI thread, assuming it will fit in the ID.  For everything 1/2" to 7/8" I will have to do UNF instead of UNC, but I can live with that.

I'm thinking now that I might need to upgrade my motor and do a belt drive before I get into the power draw bar.  The noise from the fan always running, and the gear box when it's spinning are terrible and really limits what you can hear from the actual performance of the machine.  Not to mention the huge HP loss it seams to have (I've been having trouble keeping 3200 RPM with some cuts I really should be able to do).  I think if I re-design the top plate on the mill I can make a much nicer power draw bar.


----------



## cut2cut

phazertwo said:


> I hear you on the rigid taping, it would be super nice.  I'm going to attempt some thread milling, the tooling is expensive, and its a much slower operation (at least with single point) but I mostly am going to need 3/8-16 and 1/4-20 threads, and If I get the two tread mills that can do that I think I'm out ~$140.  With those two mills I should be able to do anything with a 14-56 TPI thread, assuming it will fit in the ID.  For everything 1/2" to 7/8" I will have to do UNF instead of UNC, but I can live with that.
> 
> I'm thinking now that I might need to upgrade my motor and do a belt drive before I get into the power draw bar.  The noise from the fan always running, and the gear box when it's spinning are terrible and really limits what you can hear from the actual performance of the machine.  Not to mention the huge HP loss it seams to have (I've been having trouble keeping 3200 RPM with some cuts I really should be able to do).  I think if I re-design the top plate on the mill I can make a much nicer power draw bar.



People really rave about the motor I have.  Its been really solid but I can't say I"ve pushed it hard.  It can be had currently for $470 plus,  its very heavy so expect close to $100 for shipping.        Maybe you want more HP though ?    I just ordered another pulley and belt so I can run 1:1 if need be.  Ultimately I think it would be best to buy 4 pulleys and run any combination 2:1 ,1:2 or 1:1 with just two belts.  To keep my motor form hitting the low basement ceiling I put the pulleys down below where the gearbox was.  You could possibly have it exposed up higher to change belts but I also worried about putting too much strain on the spindle bearings due to tensioning the belt.  I considered a top bearing too to remove the side load from the belt.  I want to experiment with 1:1 to get the supposed 5400 rpm max from this motor ( I've been using 120 hz with a 3500 rpm limit ) at 1:1 rather than the 2:1 I am using now for basically 7000 rpm.   Without getting hugely expensive AC bearings for the spindle, I have my doubts I can go much higher RPM with the spindle.  Maybe too cautious....  can't be sure until something fails ! lol   So if I settle on one belt ratio for all my needs,  I can put a bearing on top, then the power draw bar and hopefully it will just run for a long time.     One other thing I like about this pulley system is that if I ever crash hard into the table or whatever, the belt might fry instead of a gearbox or the end mill just going through whatever is in its path.  I can detail more information... but one thing for sure,  if you use J profile belts get GoodYear brand.  I believe its what McMaster sells.  They are much much better than any other brand.

Maybe send me one of your fusion 360 files of a part you made that bogged down the motor.  I'll run it on my mill to see if it bogs my setup.   No promises when..  my schedule is difficult to predict.   But I'll attempt it....

Jake


----------



## TomS

cut2cut said:


> People really rave about the motor I have.  Its been really solid but I can't say I"ve pushed it hard.  It can be had currently for $470 plus,  its very heavy so expect close to $100 for shipping.        Maybe you want more HP though ?    I just ordered another pulley and belt so I can run 1:1 if need be.  Ultimately I think it would be best to buy 4 pulleys and run any combination 2:1 ,1:2 or 1:1 with just two belts.  To keep my motor form hitting the low basement ceiling I put the pulleys down below where the gearbox was.  You could possibly have it exposed up higher to change belts but I also worried about putting too much strain on the spindle bearings due to tensioning the belt.  I considered a top bearing too to remove the side load from the belt.  I want to experiment with 1:1 to get the supposed 5400 rpm max from this motor ( I've been using 120 hz with a 3500 rpm limit ) at 1:1 rather than the 2:1 I am using now for basically 7000 rpm.   Without getting hugely expensive AC bearings for the spindle, I have my doubts I can go much higher RPM with the spindle.  Maybe too cautious....  can't be sure until something fails ! lol   So if I settle on one belt ratio for all my needs,  I can put a bearing on top, then the power draw bar and hopefully it will just run for a long time.     One other thing I like about this pulley system is that if I ever crash hard into the table or whatever, the belt might fry instead of a gearbox or the end mill just going through whatever is in its path.  I can detail more information... but one thing for sure,  if you use J profile belts get GoodYear brand.  I believe its what McMaster sells.  They are much much better than any other brand.
> 
> Maybe send me one of your fusion 360 files of a part you made that bogged down the motor.  I'll run it on my mill to see if it bogs my setup.   No promises when..  my schedule is difficult to predict.   But I'll attempt it....
> 
> Jake



Hi Jake!  Can you post some pictures of your belt drive conversion?  Maybe in another thread so we don't drift off the purpose of this thread.  I'm asking because my conversion works fine but the drive spline "rattle" is driving me nuts.

Thanks


----------



## phazertwo

I would like to bump the HP, for no other reason than more is more better.

I think even just changing the current motor to a belt setup (if that's even possible) would net a huge difference in how the mill operates, and if I drop the gear set I'm sure I can start over driving the motor with out too much concern.

PZ


----------



## cut2cut

TomS said:


> Hi Jake!  Can you post some pictures of your belt drive conversion?  Maybe in another thread so we don't drift off the purpose of this thread.  I'm asking because my conversion works fine but the drive spline "rattle" is driving me nuts.
> 
> Thanks



Hey Tom,  head over here to see pictures and a better explanation of the pulley and belt setup I am using.

https://www.hobby-machinist.com/threads/my-pm-940-cnc-modifications.57976/page-3

Jake


----------



## cut2cut

Been pretty quiet here.. just stopping in to say hello !


----------



## phazertwo

HAHA!  I have been checking this thread everyday just to make sure my notifications didn't accidentally turn off.

Anyway, not much new hear.  How's your project coming pburgh?

PZ


----------



## pburgh

Hey Guys,
Sorry, i haven't been getting the notifications.  Going a little slow right now.  Having back problems.  I'm getting an MRI this friday.   Been trying to spend some time in the garage to work on the mill. I've extended my air to the garage, so i hope to start on the PDB soon.  I'm trying to tune the motors and i'm using a digital indicator.  They seem a little touchy.  What type/brand of indicators do you use?

Regards,
Doug


----------



## phazertwo

I use this mount:
https://www.amazon.com/gp/product/B01AGRAW9U/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

And this indicator:
https://www.amazon.com/gp/product/B0043F4YLO/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

I have also had good luck with craigslist around here.  I got a very nice Mitutoyo 0.0001" test indicator for $20.

PZ


----------



## pburgh

Thanks PZ, i'll have a look.  What did you end up with for steps and truns on X?  I got 1600 and 5.04 to get it as close as I could.  
Regards,
Doug


----------



## phazertwo

Here are all of my current settings... I seem to be getting great results, but I think I could do ever so slightly better.










Looks like you're quite a bit further from 5 than I am.  Do you have a pic of vid of the setup you are using to tune?

Not sure why my Z ended up so far off of 5 compared to the X and Y... Though to be really honest, I can't remember checking any features in the Z.

Here is a video of my setup, using the Amazon test indicator from above:
https://photos.app.goo.gl/KQ2vo3EeFRyIBvsF2

Also, I used Marty's spread sheet to calculate my overall turns ratio.

Hope this helps!
PZ


----------



## pburgh

Thanks PZ that helps greatly.  I got my machine tuned.    I've been struggling with getting in the garage to work on this thing.  I've had my MRI and they found another herniated disc.  So, i'm trying to deal with that now.  Do you know of any references that give some good examples to editing the gcode properly from a third party program to take advantage and integrate the tool offsets and such?  I can't seem to find any examples.  I'd like to integrate an Intercon file in a third party  CNC file but I can't seem to find any examples there either.
Thanks,
Doug


----------



## phazertwo

Bummer about your back.  I've been using Fusions tool library and the offsets in Centroid with great success.  You have to match the tool table in Centroid to Fusion, and keep them straight, but it's pretty easy.

PZ


----------



## pburgh

Hey Guys,
I was looking thru the forum and found this post by Keith: http://centroidcncforum.com/viewtopic.php?f=60&t=1801.  Please let me know your thoughts on this.  Do you think our machines will benefit by raising the steps?  Also what do you think would be a good number?  I'm finally starting to make some chips, (and breaking end mills) but my Z axis seems a little off.  When I tuned it, the indicator was on and repeatable.  BTW, I ordered an MPG.  They finally posted them on the Acorn page.  That will hopefully help in setup for parts.

Regards,
Doug


----------



## phazertwo

I think the big take away from what Keith is trying to say is that more steps = smoother motion, which is very true with a stepper motor.

(skip ▼ and read the last bit for an actual answer)
Remember that steppers are nothing like a conventional motor and they "cog" instead of rotating smoothly (you can easily feel this when you rotate one by hand when it's not powered).  The more "cogs" you have per rev (steps per rev) the smoother the motion will appear.  Think of it as frame rate for a video, a picture is simply being displayed for a short time (like 1/60sec for a 60FPS (*F*rames *P*er *S*econd) video) then it's being replaced with another VERY similar picture.  The time between pictures is SO SMALL and the picture is SO similar that it appears to be fluid and continuous.  The motor is similar, it's moving to a discrete step (a picture) and waiting a certain amount of time (FPS) to move to the next step (the next picture).  The closer the steps are together (the more similar that two pictures are), and the lower the time between steps (FPS) the smoother the motion appears.  Now, to control RPM, the drive increases or decreases the time between steps.  As that time decreases the motor lingers longer at a certain step, like a picture being displayed for to long for a video), and as the time gets to large, the motor will noticeably "jerk" to the next position.

Now that that is cleared up (this guy talks to much and doesn't make ANY sense), you can see why more steps = smoother. HOWEVER (oh crap more talking), more steps = less torque.  So it's  balancing game.  My 940 from the factory was set to 1600 and you can sertianly see it get "jerky" down around 3 IPM.  When I get mine back together I'm going to change it from 1600 steps/rev to 2000 steps/rev to see if it moves smoother, and I can keep my current speed and acceleration.  If I loose speed, I'm probably going to move it back to 1600.

PZ


----------



## pburgh

PZ,
Thanks for the reply.  I agree there should be a balance so you're not losing too much torque.  Mine was also set to 1600 from the factory, but i'm going to bump mine up to 2000 too and see how it goes.  Are you making the same mods as Jake did with a motor/bearing upgrade and convert to belt and pulley?  I had my speed set to 3125 in a program and it ran at 3000.  I didn't get a chance to check it yet, but i'm afraid i'll have to upgrade too.  Oh well...
Regards,
Doug


----------



## phazertwo

Let us know how it goes when switching to 2000.  I think everything will be just fine, especially if you're okay with lowering your rapids a bit.

I am making the same mods as Jake.  My mill was always ±30rpm from what I called for, according to my HF optical tach, so that was no problem.  The real reason I'm converting is to make it a bit quieter, and to get more RPM.  I've been running some smaller tools, and I would like to be able to spin them the appropriate speed.  Also, I think it will be much easier to do a PDB with this setup...

PZ


----------



## pburgh

Hey Guys,
I've been able to get out in the garage and work with the mill.  I'm getting frustrated though.  I've been trying to cut out the spanner wrench that's listed in the one forum post.  I thought that would be a good and fairly straight forward cut.  I've snapped several  3/16' end mills now and some of them were from learning the mill on speeds and feeds, but I've got some weird wobbling or vibration that happens sometimes.  I don't think it's chatter.  Have you experienced anything weird like that with the stock spindle/motor?  I know you all are modifying the spindle/motor setup to get a better system.  I'm starting to regret getting this mill.  It seems like every turn that something needs to be upgraded or fixed.   If you all have any  suggestions, i'd appreciate the advice.

On another note, I contacted the guy who was going to make the cnc axis parts for me before I decided to go with the turnkey system.  He's going to be making some belt drive kits for the 940.  He says the quill will be functional, but it will take a new splined shaft.  He goes by Arizonavideo99 on you tube.  Looks like he does some nice work.  Check him out on you tube.  

Well i'll see if I can get this cut out without breaking some more end mills.  But I think it's going to be a challenge,

Regards,
Doug


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## phazertwo

I haven't noticed anything like that.  Maybe you can post some of the S&F you were using?

PZ


----------



## pburgh

Hey PZ, I was able to get a successful cut.  I had to tac the spindle so I could get a true speed.  That was the issue.  
I also switched the motors to 2000 steps.  I'm having trouble getting the z axis to tune and get consistent travel.  I remember you and Jake saying you removed the manual gear to raise and lower the z axis with the handle.  I haven't removed that yet, but I'm not getting consistent travel of the axis.  I have to do some more testing to see if I can figure out where the issue lies.  I hope it's not in the axis itself.

Regards,
Doug


----------



## phazertwo

Yes, we did both remove it, and it made a serious difference in how smooth the the Z moved, and how fast I could move it.

Were you having inconsistent issues before you changed to 2k steps, or did it start when you switched?

PZ


----------



## pburgh

I think I was having trouble beforehand.  When I tuned the motor to 1" of travel it was right on.  but I think the axis moving at longer runs would start to become inconsistent.  I was trying to cut out a part that was a 1/4 thick and it ended up only going about half deep of that.  Once I saw that happening I wanted to change to 2000 and tune it again.  Then I discovered that if I set it to travel 3" I would get about 1/32 over 3.  So you can image moving around the z axis up and down for homing and such I don't think I was getting accurate movement.  At 2000 the adjustment is more touchy.  I think i'm going to remove the gear on the z.  I hope it's not too involved.  I don't need any complicated issues at this point. I also hope it's not anything to do with the ball screw or any of the axis motion parts.  I'm not too crazy about all of these mods.   My back issue is seriously hindering me from doing too much.  And i'm just talking about sitting.

On another note I was looking at your thread.  You've been pretty busy.  How do you like the the new bearings?  I think i'm going to have to do something similar.  The current motor is getting on my nerves.  I was looking into using a 1.8 DMM servo for the spindle motor.  what' are your thoughts on that?  There's a little bit about using DMM servos on the Acorn forum.
Regards,
Doug


----------



## phazertwo

The servo for spindle motor has some awesome advantages.  However at the end of the day it will limit your rpm to 3k... Which for me isn't enough.

PZ


----------



## pburgh

You should be able to at least double the speed  with a 2 to 1 or better ratio. No?
Doug


----------



## pburgh

Hey one other question.  I started to take that gear and shaft out of the z column.  Please tell me you didn't have to remove the control panel to get that out of there.  I'll be really bummed if I have to do that.  Thanks,


----------



## phazertwo

pburgh said:


> You should be able to at least double the speed  with a 2 to 1 or better ratio. No?
> Doug



Correct.  You can actually gear it to what ever speed you would like, however the largest (in my opinion) advantage to a servo spindle is the encoder.  Everything I have read says that an spindle encoder needs to be 1:1 with the spindle, which makes perfect sense when it comes to things like ridged taping.  I suppose, it might be possible with the right servo/drive that you could fool it at 2:1... but I'm not willing to guinea pig that one.

Though keep in mind I don't really care about ridged tapping.  I know Jake has it all figured out and it sounded like he was doing it relatively frequently.  I don't make many parts that use smaller threads, and I would rather thread mill, since it's a safer way to tap larger threads on smaller machines like these.

I did take the electrical enclosure off to get the the manual Z... then I realized I didn't need too.  Unfortunately I don't remember quite how to do it.  I feel like I pulled the way cover off the Z and was able to get it from there, I just needed to be creative.  I'll try to go look at the parts and see if it jogs my memory.  Sorry I don't have more info, I had a friends help for a few hours and just knocked it out and didn't think to take pics like normal.

PZ


----------



## pburgh

Hey thanks for the quick reply.  I saw that on the Acorn forum about the 1:1 ratio.  I was hoping that it would work because of the weight of a bigger 3 phase motor. 
On the gear, it looks like there is an allen cap screw holding it on.  I'm hoping to remove that and work the gear off.  From there I was hoping to remove the shaft from the outside.  I don't know how tight those bearings are packed in there.  This is disappointing that this crank doesn't work like it should.   Did you find that your headstock wants to lower itself once you take the power away from the stepper?

Doug


----------



## cut2cut

Hey guys,  lots has kept me away from milling for quite some time  but I hope to get back on the horse,   Will try to remember what was needed to remove the Z manual crank.  I vaguely remember documenting it somewhere, I hope! 

Jake


----------



## phazertwo

pburgh said:


> Hey thanks for the quick reply.  I saw that on the Acorn forum about the 1:1 ratio.  I was hoping that it would work because of the weight of a bigger 3 phase motor.
> On the gear, it looks like there is an allen cap screw holding it on.  I'm hoping to remove that and work the gear off.  From there I was hoping to remove the shaft from the outside.  I don't know how tight those bearings are packed in there.  This is disappointing that this crank doesn't work like it should.   Did you find that your headstock wants to lower itself once you take the power away from the stepper?
> 
> Doug



It's not about torque, though torque is important too.  It's about rotation positional accuracy.  If the encoder is 1:1 with the spindle it knows EXACTLY what speed the spindle is moving and the index mark on the encoder will be in the same spot each rotation.  Either way, the more I think about it, I think the best bang for your buck is just upgrading your motor and getting an encoder like Jake did.  His setup seems to work, and it would be very easy to change over to a belt drive and just add an encoder.  But again, unless you are going to ridged tap it's not necessary.

Also, just to be clear, my manual Z always worked correctly.  Any gear set will add friction and therefore eat up power, this gear set is no exception.  There is nothing technically wrong with the manual Z, it's just not needed, so getting rid of it gets you a little more chooch in the Z.

Anyway, I got out to the garage and looked at the gear.  There is a socket head screw on the end, it takes a 6mm Allan.  After I got the screw off I used a chisel between the bearing and the gear to drive the gear back.  I think I had to use a pry bar to get it all the way off, rotating the shaft ~180° between each push.  Then I did the same for the bearing (I think).  Honestly if that doesn't work, you're better off sticking a sawzall in there and cutting the shaft...  



cut2cut said:


> Hey guys,  lots has kept me away from milling for quite some time  but I hope to get back on the horse,   Will try to remember what was needed to remove the Z manual crank.  I vaguely remember documenting it somewhere, I hope!
> 
> Jake



I was actually about to send you a message and see how it was going.  I'd love to see some video of probing and ridged tapping!

PZ


----------



## N2XD

I am about to embark on a PM-940M cnc retrofit. I am going to use the Centroid Acorn board. This will be my first cnc endive and have enjoyed reading these postings. Any pict5ures or drawings that you may feel to be helpful would be greatly appreciated. I'm located in western North Carolina and have not started on dismantling the 940 yet. I plan on securing some parts first. I have the Acorn board here and will be doing the initial power and software loading later today or tomorrow. I hope some of my questions do not bore anyone. The age here is 69 and I am retired. I just want o bring the 940 up to 2018 standards. And besides it should be fun. Thanks.


John


----------



## Rickwjenn

Got to the next level this weekend.

Now that 940CNC is working on all axis and variable speed spindle, I wrote some simple g code programs, loaded them in CNC 12 and 1) used a pen to draw precise square and four arcs inside of it and 2)same thing with cutter in aluminum making passes at 0.001, 0.002, and 0.005 inches of cut.  Next up is a 3D part via fusion 360 for my dad’s 58 chevy truck


----------



## pburgh

Good luck to you John.  You made the right choice for the Acorn controller.  You should be able to set this thing up pretty nice some of the parts available.  Be sure to check out Sam at CNC4XR7 on You Tube.  He has a PM-727 he's modified.  He also does some nice reviews on the available equipment.
Regards,
Doug


----------



## pburgh

Rickwjenn,
That's pretty cool that you're making some good progress.  Keep us posted on how things go.
Regards,
Doug


----------



## Rickwjenn

Thanks!  Will do. Power draw bar is on the horizon!


----------



## Rickwjenn

pburgh said:


> Rickwjenn,
> That's pretty cool that you're making some good progress.  Keep us posted on how things go.
> Regards,
> Doug





pburgh said:


> Rickwjenn,
> That's pretty cool that you're making some good progress.  Keep us posted on how things go.
> Regards,
> Doug



Doug thanks.  How is your machine going?  Cutting metal yet?  Really appreciate all your posts to help others.


----------



## Rickwjenn

Some videos of the PM-940CNC with Acorn!

PM-940CNC Setup

First Metal Cutting


----------



## phazertwo

Rick, looking good!  I see you have 4 stepper controllers... did you get the 4th axis?

A few suggestions, I would ditch the handles on the X and Y...  They do not feel good when they hit you.  I would also remove manual Z, machine moves smoother and faster after that's removed.

PZ


----------



## Rickwjenn

Yes - I have the fourth axis stepper motor and chuck that mounts on the table.   Have not used it yet.

I am going to take the z axis manual out this weekend.  It makes way to much noise.....  Great point on the X & Y handles - they will come off next


----------



## RADustin

Great thread, curious if you would still advise to start with the turn key CNC machine or build up one from a hardened way manual PM-940?  

I'm starting the journey of planning a purchase/build so I appreciate you detailing all the experiences you have had.


----------



## Rickwjenn

RADustin

I would definitely get the PM 940 with the CNC option.  While, you would likely use different/better stepper motors, the overall effort to 1) add ball screws, 2) make / buy the Stepper motor mounts, and 3) build/buy/complete the controller cabinet (wiring, PS, etc) is not a good use of your time IMO.   

If you start with the PM CNC set up you will be focused on adding the Acorn board and learning who to use the stepper motors.  

I found the overall PM CNC quality to be pretty good.  The wiring harness (which is extensive) is well labeled and the Controller cabinet is cleanly designed and organized.   The documentation is fair but with a little web searching I got the product manuals for all the key parts - Delta VSD, Leadshine Motors/Drivers, and Powersupply. 

Now that mine is up and running I see zero need to replace any of the PM supplied CNC hardware - ONCE the junky Chinese Motion controller is out!    Did this over the weekend with some simple g-code:


----------



## RADustin

I appreciate the feedback!  

The machine would be my tool and not project(well once its running well enough)- I need parts for my projects.  So you're point about use-of-time is very important.  

Thanks.


----------



## Rickwjenn

While I am a beginner here, so far I have found the PM 940 to be very mechanically accurate.  Also highly recommend the Centroid MPG once you swap the the Acorn in....


----------



## N2XD

For the fellows who have done the spindle belt drive mod. Where did you locate the pullies and belts? Thanks.


----------



## phazertwo

http://www.ametric.com/s-250-pulley.aspx

These guys have a decent selection, though I have not poured through their timing belt section like I have their Poly-V section.

PZ


----------



## cut2cut

Hi Guys,  Hope you are all well !  I haven't been doing much machining at all due to many things but I'm ramping up again.  I just temporarily installed a cheap bore through spindle encoder ( I plan to post what I have learned wrt the spindle encoder )  and next is a power draw bar.  I watched CNC4XR7's youtube video about his recent power draw bar for his machine and learned a fair bit already but unsure which cylinders to buy and if they are stackable.   Hoping to get clarity on that.   Doug, please get a hold of me if you have a chance, I have lost your contact info.
Cheers,

Jake


----------



## phazertwo

Good to hear from you Jake!  Looking forward to your updates!

PZ


----------



## pburgh

Hey Guys, sorry I wasn't getting all of the messages thru email.  To answer a couple of questions:
If I was physically able, i'd build the machine using the base unit with hardened ways.  There is a guy, Arizona Dave Arizonavideo99 on youtube, who makes an axis kit for the mill.  He's just now starting to sell them.  Also, with the Centroid controller and DMM drives/motors, I think you can setup a pretty sweet machine.

For the belt drive option, check out CNC4XR7 on you tube.  He's starting to sell kits for the PM-727 and some guys are asking him about the PM-940.  Sam and Wyatt are very stand up guys that do some very nice work.  I had them modify a spindle bearing carrier that I got from Jake, and they did a nice job.  I have still to set it up, but that should be coming.
Hope this helps.
Regards,
Doug


----------



## TomS

N2XD said:


> For the fellows who have done the spindle belt drive mod. Where did you locate the pullies and belts? Thanks.



I made my own pulleys and bought my Goodyear belt on eBay.


----------



## N2XD

phazertwo said:


> http://www.ametric.com/s-250-pulley.aspx
> 
> These guys have a decent selection, though I have not poured through their timing belt section like I have their Poly-V section.
> 
> PZ


Thanks PZ they do have a great selection.


John


----------



## phazertwo

N2XD said:


> Thanks PZ they do have a great selection.
> 
> 
> John



No problem.  To give credit where it's due, Jake actually found those guys.

PZ


----------



## N2XD

Another question? I'm pretty sure I know the answer. On the Z-axis ballscrew  did any of you provide support on both ends of the ballscrew? I noticed on some of the conversions on lighter machines  only one end had support (the top end which would be the drive end). I'm just about finished machining the parts needed for the z-axis.
Thanks.

John


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## cut2cut

N2XD said:


> Another question? I'm pretty sure I know the answer. On the Z-axis ballscrew  did any of you provide support on both ends of the ballscrew? I noticed on some of the conversions on lighter machines  only one end had support (the top end which would be the drive end). I'm just about finished machining the parts needed for the z-axis.
> Thanks.
> 
> John



My Z is only supported on the top because I removed the standard captured end.  However i’m not certain it’s the safest approach due to the single ball nut being the only thing holding the entire weight of the head from crashing ( due to gravity if something fails in the ball nut assembly. )
Jake


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## N2XD

That is what I was thinking. What size ballscrew are you using?

John


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## cut2cut

N2XD said:


> That is what I was thinking. What size ballscrew are you using?
> 
> John


I don’t know off hand and cannot look now but have that info somewhere in my manual ,  I bought the pm940cnc so it’s not a retrofit.


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## phazertwo

Did anyone make a model of that air cylinder?  I'm working on my PDB design, and want to use it...

PZ


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## Rickwjenn

N2XD said:


> For the fellows who have done the spindle belt drive mod. Where did you locate the pullies and belts? Thanks.



What are the key reasons to move to spindle belt drive setup vs. the gears?    I have been machining a few CNC parts with my 940 CNC w/VFD and have not picked up an issue with the gears....


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## TomS

Rickwjenn said:


> What are the key reasons to move to spindle belt drive setup vs. the gears?    I have been machining a few CNC parts with my 940 CNC w/VFD and have not picked up an issue with the gears....



The main reason is RPM.  The gears have a speed limitation.  For instance, my PM-932 had a top speed of 1970 rpm.  I called Matt and asked him about going with a 3450 rpm motor.  He said don't do it as the gears aren't rated for that speed.  Not to mention the potential for increased gear noise.

I converted my mill to a belt drive and with the pulley ratio I have I can get to 8800 rpm.  And it's quieter than the original gearhead at 1970 rpm.


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## Rickwjenn

TomS said:


> The main reason is RPM.  The gears have a speed limitation.  For instance, my PM-932 had a top speed of 1970 rpm.  I called Matt and asked him about going with a 3450 rpm motor.  He said don't do it as the gears aren't rated for that speed.  Not to mention the potential for increased gear noise.
> 
> I converted my mill to a belt drive and with the pulley ratio I have I can get to 8800 rpm.  And it's quieter than the original gearhead at 1970 rpm.




Got it - that makes sense.  My PM-940 maxes out at 3200 rpm (in the "High Gear") setting and VFD motor flat out.      

Without a VFD you have to change pulleys for different speeds.  With a VFD, I could use three pulley ratio/sets to have a nice range of Low (100-500), Med (1000-3000), and High (3000+).

Will have to give it some thought.   Thanks for the information.


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## srecord1

phazertwo said:


> Wow, that's about half cost of the Centroid DP-4... But still way more than the cheapo Tormach unit.  Hopefully you get what you pay for and judging by Sams review, you do.
> 
> It would seem that your panel layout is quite a bit different than mine.  Can you snap an overall shot of the cabinet layout, I would like to see how yours is done.  If I ever get my internet situation figured out I'll post some pics of how I mounted mine.
> 
> PZ


Did you ever get a response on advantages or disavatages over the centroid dp-4 probe? Im extremly interested as im ready to buy one as well!


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## phazertwo

srecord1 said:


> Did you ever get a response on advantages or disavatages over the centroid dp-4 probe? Im extremly interested as im ready to buy one as well!



Wow, that was 1.5 years and a kid ago.... I don't even remember typing that.  From what I remember about the research I did on probes is that most probes are probably better than our machines, but that also depends on if you know how to use them.  Also, you have to pony up for the "digitizing" software package from Centroid if you want to use them with the Acorn for anything but corner finding.  This is why I didn't buy a probe, I have had other priorities with the machine over paying that much to probe.

In the end, I decided I would likely go with the Drewtronics S5000LED.  It's cheaper and the resolution is good enough for 99% of what I do.  I figured for $170 you can learn how to probe and decided what probe is right for you.


			https://drewtronics.org/s5000led
		


PZ


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## srecord1

So to clarify things you ended up buying the drewtronics and  the unlock feature from centroid? as im assuming that this is required.  is that probe capable  of digitizing with the unlock code from centroid? Thanks so much for your quickness on time you have taken with your response!


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## phazertwo

Sorry I wasn't clear on this point.  I don't have a probe.  Once I realized I need the digitizing package ($400) to do any type of probing more complicated than picking up a corner, I dropped it in in favor of some other upgrades on the mill like the spindle.

From what I understand, any probe should work with Acorn, assuming it's wired properly.  Once a probe is operating with Acorn, it's possible to digitize, regardless of the type of probe.

Also, you're welcome.

PZ


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