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Pm-940m-cnc (pre-assembled)

phazertwo

Active Member
Active Member
#61
So you are running a larger buffer and that solved it. Good to know....

Mine was automagically set, probably the default. I'm using a computer running widows XP, btw , which may have less overhead / more efficient. And coupled with a possibly faster computer I can get away with the default settings.
Yeah, I tried it with the same buffer that you have and it still had the same problem. I wonder if this has more to do with the speed of my computer. The computer I have on the mill right now is pretty weak, even as far as XP machines go. I have another one that I can get setup to run XP, I'll probably start that process over the weekend, along with transferring all of the settings.

PZ
 

cut2cut

Active Member
Active Member
#62
Jake,
I can't thank you enough for sharing how you relocated the electrical enclosure. I'm expecting my 940 cnc in about 4-5 weeks and will likely do the same as you.

Rod in San Francisco
No problem, let me know if you need any more detail and I'll try to help.

Jake
 

cut2cut

Active Member
Active Member
#63
Yeah, I tried it with the same buffer that you have and it still had the same problem. I wonder if this has more to do with the speed of my computer. The computer I have on the mill right now is pretty weak, even as far as XP machines go. I have another one that I can get setup to run XP, I'll probably start that process over the weekend, along with transferring all of the settings.

PZ
EDIT : Retraction ! The hiccups were actually bad G-Code from FUSION 360 !

Well, I just experienced the same thing you had happen , "hiccups" while running G code. Adding to the buffer didn't get rid of it completely. It has only shown up during short segments with a lot of small lines of code with quick changes of direction. When it happens the spindle speed also increases and then backs down until the next "hiccup". Even if this is easily curable I'll be accelerating my move away from Mach 3+usb to LinuxCNC via ethernet or PCI interface.

Jake
 
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phazertwo

Active Member
Active Member
#64
Now I have a new problem. If I set x0y0 at somewhere, then jog atleast an inch away from that in both x and y, then run a G0X0Y0... it never returns to quite the same spot. It's usually .05-.4" off on the DRO. This doesn't make any sense to me, even if it is missing steps the DRO should still go to zero correct?

Could you do a little test of the above Jake and let me know what yours does?

PZ
 

cut2cut

Active Member
Active Member
#65
Now I have a new problem. If I set x0y0 at somewhere, then jog atleast an inch away from that in both x and y, then run a G0X0Y0... it never returns to quite the same spot. It's usually .05-.4" off on the DRO. This doesn't make any sense to me, even if it is missing steps the DRO should still go to zero correct?

Could you do a little test of the above Jake and let me know what yours does?

PZ
I tested mine 6 times exactly as you asked. When instructed via the G0x0y0 command Mach3's DRO returned back to 0.0000 most times and a few times the DRO would show .0001 of true "Zero". Yeah, I agree, since it is an open system, I would think Mach3 should "think" it moved back to exact ZERO every time.

Jake
 
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phazertwo

Active Member
Active Member
#66
Thanks Jake!

Well, I'm uninstalling and reinstalling Mach 3 for round 3... I really am at a loss to what I am doing wrong here, unless running the demo version is my problem, though I have not ready anything that would suggest it would.

PZ
 
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Davd Flowers

Active Member
Active Member
#67
I think that the .0001 may be mach trying to hit the best possible mark with what it has to work with.
Basically something like this....maybe?
1.8 degree steppers at half step is 400 steps per revolution. Coupled to a 5mm pitch ball screw which travels .19685" per revolution or .000492125 per half step. so if your asking it to make .001" it can never really move the .001" so it comes as close as it can????
 

cut2cut

Active Member
Active Member
#68
Yeah, mine is possibly due to an acceptable "rounding" type error , but PhazerTwo's is far beyond a rounding error, right !!?
 
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phazertwo

Active Member
Active Member
#69
I think that the .0001 may be mach trying to hit the best possible mark with what it has to work with.
Basically something like this....maybe?
1.8 degree steppers at half step is 400 steps per revolution. Coupled to a 5mm pitch ball screw which travels .19685" per revolution or .000492125 per half step. so if your asking it to make .001" it can never really move the .001" so it comes as close as it can????
Yes, this is correct. With 8000 Steps/in I should be able to get a resolution of 0.000125.

Yeah, mine is possibly due to an acceptable "rounding" type error , but PhazerTwo's is far beyond a rounding error, right ?
FAR beyond. When I am 0.050 off that is 400x the rounding error I should be getting... Not acceptable.

Last night I re-installed Mach 3 and started playing with the buffer time. If I set the buffer time high then my error goes up, and my "jumping" goes away. If I set the buffer low my error goes down but the "jumping" shows back up. Hopefully I can find an acceptable balance of no jumping and accurate enough. All and all, I am very unimpressed with the nMotion controller which is super unfortunate because it seems to be a capable unit short of its few issues.

PZ
 

Davd Flowers

Active Member
Active Member
#70
Yes, this is correct. With 8000 Steps/in I should be able to get a resolution of 0.000125.



FAR beyond. When I am 0.050 off that is 400x the rounding error I should be getting... Not acceptable.

Last night I re-installed Mach 3 and started playing with the buffer time. If I set the buffer time high then my error goes up, and my "jumping" goes away. If I set the buffer low my error goes down but the "jumping" shows back up. Hopefully I can find an acceptable balance of no jumping and accurate enough. All and all, I am very unimpressed with the nMotion controller which is super unfortunate because it seems to be a capable unit short of its few issues.

PZ
And this is repeatable on all 3 axis??
 

phazertwo

Active Member
Active Member
#71
And this is repeatable on all 3 axis??
I assume you're talking about my statement on the buffering time vs accuracy. So far yes, it is repeatable on all 3 axis. I only tested for ~5min but every time I sent it to a random x,y,z position running a low buffer time it would get there within 0.0001". The further I cranked the buffer time up the larger that 0.0001" got. I probably won't have time to do more testing until Wednesday night, I will post up more results.

HOPEFULLY I can actually run some g-code on Wednesday (just a marker in the spindle)!

PZ
 

cut2cut

Active Member
Active Member
#72
I found the problem that was causing me "hiccups". Fusion 360 created some VERY strange G-Code... Note to self, always check the G-code for anomalies if the mill is acting strange during a job. So I edited my above comment that pointed the blame at the 940cnc 2017 revision USB controller hardware Nevermind....

Also, briefly I just tried a newer i5 64 bit computer with a fresh install of windows 7 professional 64 bit and downloaded and installed a demo copy of Mach3. Seemed to work quite well and while using the default buffer size in the nMotion plugin configuration settings.
I tested the g-code that hiccuped, and also moved the x and y around after zeroing, and then used the G0X0Y0 command and it landed at .0000 or .0001 every time.

Jake
 

phazertwo

Active Member
Active Member
#73
I found the problem that was causing me "hiccups". Fusion 360 created some VERY strange G-Code... Note to self, always check the G-code for anomalies if the mill is acting strange during a job. So I edited my above comment that pointed the blame at the 940cnc 2017 revision USB controller hardware Nevermind....

Also, briefly I just tried a newer i5 64 bit computer with a fresh install of windows 7 professional 64 bit and downloaded and installed a demo copy of Mach3. Seemed to work quite well and while using the default buffer size in the nMotion plugin configuration settings.
I tested the g-code that hiccuped, and also moved the x and y around after zeroing, and then used the G0X0Y0 command and it landed at .0000 or .0001 every time.

Jake
This is good to know. I have a much better computer just sitting around that I can load XP on and give Mach 3 another shot, hopefully with a smaller buffer. I'll have to start the install process tomorrow and see how far I get.

PZ
 

phazertwo

Active Member
Active Member
#74
Made my first chips last night! Didn't take a picture because there wasn't really anything to take a picture of. I simply ran G1 codes around a block of aluminum for no reason other than to make some chips and say that I used my mill!

Hopefully I will get a little bit of play time over the next few days and actually cut something out.

PZ
 

rodjava

Steel
Registered Member
#75
Ok, sorry for the delay. Here are the pendant pictures I promised.

I'm still getting the software configured little by little. A fellow pm-940CNC owner has helped me test the spindle, and also showed me some wiring for things like the coolant pump that were not designated anywhere.

X Y and Z function so far, so the new controller appears to be functioning.

So far I love the rigidity and smooth ground ways. I have yet to check for backlash and such, but the fit feels good so far. I do have a knocking sound in the Z that I need to inspect. I believe it has to do with the slop in the hand crank gear interface with the ball screw...or possibly the screws holding the ball nut are not tight. If it is the hand crank slop I'll probably remove the hand crank assembly entirely, unless it serves to keep the head from creeping down on its own weight ?

Cheers,

Jake

View attachment 225057 View attachment 225058

Jake,
I'm trying to figure out the wiring for the coolant pump too. Any pictures or info how the 3 wires connect to the pump? I emailed Matt, but it's Sunday.

Rod in San Francisco
 

cut2cut

Active Member
Active Member
#76
Jake,
I'm trying to figure out the wiring for the coolant pump too. Any pictures or info how the 3 wires connect to the pump? I emailed Matt, but it's Sunday.

Rod in San Francisco
I haven't actually wired it but I asked a fellow with the 2016 revision of the pm 940-cnc' if he could send his wiring. I don't recall if the terminal block looks exactly the same but here is what he sent me.
If you get yours wired up and working please send a picture of your pump wiring !

Jake
 

Attachments

cody.williams

Swarf
Registered Member
#77
Hey Guys

So long story short, I'm a new employee at a small lab. They had purchased a PM-940M a few years back and never had it set up. This past week I have been in charge of setting it up. I've been able to get the mill to jog in all directions but I have not been able to get the spindle to turn at all. I've tried everything listed in this thread, but without any luck. I did notice the VFD throwing a AErr code which directed my to check the ACI Wiring. I checked the M1 and M2 wires and everything seemed fine, still getting the error...

I also have been having problems with the physical E-Stop Button. It is wired to I11 on the JNC-40M motion controller, I have the input mapped to 11 on Mach3, yet in the diagnostics page when its pressed Output 3 starts flashing.

I am new to this CNC thing and at a complete loss. Any and all suggestions will be appreciated :)
 

cut2cut

Active Member
Active Member
#78
I don't have the older controller so I doubt I can help you Cody, however I've recently converted my mill to use Linux CNC which required new electronics / controller, so if you ever need or want to swap out for the latest ( 2017 revision ) controller for the pm940 cnc , I will be selling my factory nMotion controller with pendant.
I also am going to belt drive and in the process will have the spindle motor for sale too. For anyone interested, I suppose it's best to send me a private message.

Jake
 

phazertwo

Active Member
Active Member
#79
I don't have the older controller so I doubt I can help you Cody, however I've recently converted my mill to use Linux CNC which required new electronics / controller, so if you ever need or want to swap out for the latest ( 2017 revision ) controller for the pm940 cnc , I will be selling my factory nMotion controller with pendant.
I also am going to belt drive and in the process will have the spindle motor for sale too. For anyone interested, I suppose it's best to send me a private message.

Jake
Hows the new setup? Which controller did you end up with?

I have been battling more with the buffer time... and somewhat frequently it still seems to just not do what I want it to do...
 

cody.williams

Swarf
Registered Member
#80
Hi,

Is there any way anyone could send me their parameters on their VFD. Matt seemed to indicate that with the machine not running for a long time, the internal memory on the VFD might have went blanked and the parameters reset.
 

cut2cut

Active Member
Active Member
#81
Hows the new setup? Which controller did you end up with?

I have been battling more with the buffer time... and somewhat frequently it still seems to just not do what I want it to do...
I am now using Linux CNC with the Mesa 7i76E ( the E stands for ethernet ). It wasn't an easy as "plug and play" because installing LinuxCNC was a bit of a hassle and I had to rely on my brothers help quite a bit with re-wiring ( of the relays mostly ) for the 7i76e and the VFD to talk to each other. Also the limit and home switches needed a bit of detail too ( basically the common leg had to be powered ).

Last time I used the mill the spindle was getting quite warm and now it feels very tight, so I'm going to have to take it apart to make sure its greased properly and not set too tight.

Jake
 

phazertwo

Active Member
Active Member
#82
I am now using Linux CNC with the Mesa 7i76E ( the E stands for ethernet ). It wasn't an easy as "plug and play" because installing LinuxCNC was a bit of a hassle and I had to rely on my brothers help quite a bit with re-wiring ( of the relays mostly ) for the 7i76e and the VFD to talk to each other. Also the limit and home switches needed a bit of detail too ( basically the common leg had to be powered ).

Last time I used the mill the spindle was getting quite warm and now it feels very tight, so I'm going to have to take it apart to make sure its greased properly and not set too tight.

Jake
That is awesome. You'll have to keep us updated on how it's working out.

What made you choose the Mesa over the SmoothStepper?

PZ
 

cut2cut

Active Member
Active Member
#83
That is awesome. You'll have to keep us updated on how it's working out.

What made you choose the Mesa over the SmoothStepper?

PZ
The Mesa is supposed to be solid hardware and also used by Tormach so if I ever try to use pathpilot control software it will be less struggle to implement it, theoretically !
Jake
 

phazertwo

Active Member
Active Member
#84
I just glanced over the manual for the Mesa... a step far above the nMotion for sure. It looks like the hardest thing to over come would be the spindle speed control, going from PWM to essentially a POT. How is linux CNC vs Mach 3? I am VERY interested in changing to Linux, so don't hold back on review!

PZ
 

cut2cut

Active Member
Active Member
#85
Yeah, I will. Probably will start a new thread though, so as to not hijack this one.
The wiring isn't very difficult now that I have a schematic. I'll share that too.

Jake
 

cut2cut

Active Member
Active Member
#86
Hi, sorry, I haven't had much time to work on the mill but just yesterday I installed AC bearings in the spindle. I don't know if it's successful yet as I haven't checked runout tand actually cut anything but I do want to caution others about something I ran across without regard to the bearings you use. When I tore apart the spindle the interior of the spindle cavity had loose "scale" from the casting process. While I had it apart I used a wire wheel on an extension to loosen up and remove the existing scale so it won't come off anymore and easily get into my fresh bearings.

Jake
 

cut2cut

Active Member
Active Member
#88
..... thought about clearpath servos, but that's some money right there !!!

But I actually have already changed the spindle motor...
 

rodjava

Steel
Registered Member
#89
I would like to change my spindle motor at some point. It would be great if someone would post how they did it and the pros and cons of the install.

Rod in San Francisco