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Taking the CNC Plunge

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TomS

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I would recommend a 5K speed pot, the spec. for the WJ200 is 1K, so anything in the 1-5K should be OK. The P1 and P2 are thermostats (P-Stats), alternatively I often connect them either to the E-Stop circuit or there is the inputs/settings to connect them to the WJ200 as noted above, which will shut down and give you an error code. The connections will differ if you use source vs. sink logic. Consideration should be given to if you want the P-Stat to shut down the motor AND also send a stop single to your CNC program, similar to a limit switch. Shutting down the motor in the middle of a cutting sequence could be problematic. It is also possible to use a simple 2 pole 24VAC relay powered through the motor P stat which also provides power to the main power contactor and connect one pole to the the VFD P-Stat contacts and the other to CNC program stop function. Breaking power to the E-Stop, Power or the P-Stat opens turns off which opens the relay and stops the motor, powers down the VFD (this takes about 30 seconds) and sends a stop signal to the CNC program.

I had previously posted a 3 wire connection diagram that can be used with momentary buttons as opposed to 2 wire sustained on to input 1 and 2. It also utilizes the current machine E-Stop system to power down the VFD. A few people have used this on their PM mills. I am a bit unclear if this machine is going to be used for CNC, then the computer/program would control both the direction and speed of the motor directly unless you are manually going to be doing this.
I found your schematic last night, couldn't remember where I first saw it, and studied it thoroughly. Bear with me as electricity is not my strong point. If I understand your logic the factory supplied for/rev switch is still used to control spindle direction. I understand the function of the two momentary switches; one for On and one for Off. Is this correct? Is the symbol in the wire between forward and reverse a diode?

For info my mill is CNC but will manually be changing speed and spindle direction until I move onto phase 2. Phase 2 will be a ESS and spindle control board upgrade.

Til the next onslaught of questions, thanks for your help.

Tom S.
 

TomS

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P1 and P2 are a thermoswitch inside your motor; you are supposed to hook them up so it kills power to the motor if it overheats. The Hitachi WJ200 has connections that are designated for that purpose.
1. Set code C005 to "19" (Page 4-6 "PTC) - (activates thermal protection)
2. P1 and P2 should be hooked between terminal "5" and "L" (page 4-30).

5K or 10K pot will get the job done. You don't want to go much higher than that, since EMI will induce sufficient current to cause unstable response.
1. Set Code A001=00 (Page 3-12) -activates external pot.
2. Connect it between "L" and "O" (page 4-5).

Yes, you want to hook your FWD/REV switch into the VFD. You probably also want to buy an E-Stop button and hook that into the VFD too.
1. Set Code A002 =01 (Page 3-13) - activates terminals for control
2. Lead from the FWD switch terminal to "1" (Page 4-16).
3. Lead from the REV switch terminal to "2"
4. Switch power to "P24"

Not sure what on your switch equates to which position. Basically, when the switch is in FWD, it should allow current to flow from "P24" to "1". When in REV, "P24" to "2".

A couple other points:
1. You will want to set up regenerative braking to slow down faster
2. Make sure that your VFD controller box has good ventilation. That thing can be putting out 100W of heat. You notice in the manual they specify installing it in a box that is at least 4" clearance above,4" below, and an 2" on each side. That might be more than needed, but in the little box you have you might end up having to install a fan to keep ventilation flow (page 2-8).

EDIT: Hitachi, not Fujitsu....
Tim - your input is appreciated. I've got four wires coming from my for/rev switch. Are you saying two go to P24, one goes to terminal 1 and the remaining one goes to terminal 2? Sorry for any stupid questions but I want to make sure I don't fry the VFD because I mis-wired something.

Yes, my plan is to add a fan to the enclosure. Got it on the P1/P2 leads. Seems simple enough.

Tom S.
 

jbolt

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Not sure if the picture of the VFD in the box is the way you intend to mount it but you will want the control panel facing you for programming etc.
 

TomS

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Not sure if the picture of the VFD in the box is the way you intend to mount it but you will want the control panel facing you for programming etc.
Unfortunately that's the only way it will mount. It's a 12" x 12" x 6" enclosure. I opted to go with this enclosure because it was in stock locally. My mill has been down for a month and I want to get it running. Worst case is I leave the wiring a bit long and do the programming with the VFD out of the enclosure. The screen is visible and I can get to the buttons the way it is. Thankfully I only have to program it once.

Tom S.
 

TomS

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Thanks to mksj and others I've got my VFD wired. Next step is to wire the motor but I can't do that until I get the spindle grease so I can assemble the spindle. I'd like to do the VFD programming while waiting for the grease but I think I heard that you can't run the VFD unless it's connected to the motor. Is this true?

Tom S.
 

TomS

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Success, at last. Got my spindle together and installed and ran it with the belt. No abnormal issues except a rattle coming from the spindle. It's the spindle spline rattling in the drive sleeve. I know it's the spline and drive sleeve because when I tighten the spindle lock the rattle becomes louder. I ran for 15 minutes at 900 rpm, then another 15 minutes at 1800 rpm, then ramped up to 3600 rpm and finally a run of 6400 rpm for another 15 minutes. Highest measurable temp was 103 deg. F at the drive sleeve bearings. It also whines a bit but my understanding is this is normal. I seem remember there is a parameter setting that helps to reduce the whine.

I got a over-voltage error when I quickly turned the pot down from 90 hz to 0 hz. It's got something to do with dynamic braking I'm sure. I'll look through the parameters and figure out which one to change. I'll try it with no braking and see how long it takes to coast down.

All in all a great learning project. Thanks to MKSJ (Mark) and several others for chiming in with answers and suggestions. I would not have taken on this project without their help and guidance. I've attached the files MKSJ sent me so that others can see what I did. Hopefully it will help someone else. I tried uploading a short video of the mill running at 6400 rpm but the file is huge. I'll see what I can do about reducing the file size.

Tom S.

KM2 and KM3 are no longer there nor is the DC Z axis lift motor.
VFD Wiring Diagram.jpg
 

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tmarks11

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If you install an external braking resistor ($20-30 on eBay), it will help the rapid deceleration. You would be able to stop the spindle in less than a second.
 

jbolt

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I had the spline rattle and fixed by greasing it.

I don't use electronic breaking with spindle controlled from Mach3. There is enough drag with the belt drive to slow it down quickly enough. I do like it on the lathe though.
 

TomS

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I had the spline rattle and fixed by greasing it.

I don't use electronic breaking with spindle controlled from Mach3. There is enough drag with the belt drive to slow it down quickly enough. I do like it on the lathe though.
Thanks for the tip on greasing the spline. I'll give it a try.

I was thinking along the same lines as you on electronic braking. I've looked through the parameter list and there are several that address overvoltage fault error. I'm going to change them one at a time and see what effect they have on decel time and if I still get the dreaded overvoltage fault.

Tom S.
 

TomS

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If you install an external braking resistor ($20-30 on eBay), it will help the rapid deceleration. You would be able to stop the spindle in less than a second.
Thought about a resistor but this project has stretched my electrical skills to the max. For the moment I'm going to play with the deceleration features and see if I can get around the overvoltage fault by increasing the decel time. Phase 2 will be an upgraded BoB, ESS, and spindle control board. I'll look at it again when I do Phase 2.

Thanks,


Tom S.
 

TomS

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This is my first time uploading a video. It is a clip of my mill running at 6400 rpm (90 hz) after completing the VFD/belt drive conversion. Sure beats a top speed of 1970. Not sure why it turned 90 deg. or how to correct it. File size started out at 63 mb. Got it down to 4 mb. Still have some fine tuning to do and a few details to finish up. If you listen closely you can hear the spindle spline/drive sleeve rattle I mentioned in my post above.

Tom S.
 

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TomS

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Maybe I missed it, but how is the driven pulley attached to the spindle? Awesome thread BTW....

Thanks for the kinds words. As most others have done when converting their mills to belt drive I modified the splined sleeve (part 57) on the attached drawing by machining off the gear and cutting a snap ring groove to retain the pulley. Some have threaded the end of the sleeve for a retaining nut. The sleeve is then assembled inverted from it's original orientation. See the picture below of the finished sleeve.

Tom S.

20161205_153916_resized.jpg
 

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Davd Flowers

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OK, I think I see.
The pulley is pressed and keyed to the splined coupler, but then does it just sit over the spindle shaft or is there any type of bearing support on it?
 

TomS

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OK, I think I see.
The pulley is pressed and keyed to the splined coupler, but then does it just sit over the spindle shaft or is there any type of bearing support on it?
There are two ball bearings and a spacer that support the sleeve. These pictures are not of my assembly but illustrate how it's done. You will see that this assembly has inner and outer bearing race spacers. That's because a retaining nut is used to compress the bearings against the lower snap ring. Here are a few pictures of the sleeve assembly and installation.

Let me know if you need more info.

Tom S.

Individual components that make up the assembly. Note that this picture shows a retaining nut at the top. My assembly uses a snap ring and no inner bearing race spacer. See the snap ring between the two bearings? That fits into a groove in the bearing bore of the cover plate and retains the sleeve assembly in the cover plate.
gdmP1030063.JPG

Here are the components assembled on the sleeve for illustration only. To assemble the parts in the cover plate you first install the snap ring in the bearing bore, then press in the bearings. Drop in the bearing spacer(s), slip the sleeve into the bearings, install the key and pulley and tighten the nut or in my case install the upper snap ring.
gdmP1030062.JPG

The sleeve assembly, minus the pulley installed in the cover plate.
gdmP1030080.JPG

Bottom view of the cover plate.
gdmP1030081.JPG
 

Davd Flowers

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Im thinking that this is a mod I want to do sooner than later :) Now if only my ball screws would hurry up and get here!
 

TomS

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Im thinking that this is a mod I want to do sooner than later :) Now if only my ball screws would hurry up and get here!
It's worth doing sooner than later. Machining aluminum with a 1/4" carbide end mill at 1970 rpm will test your patience. I've had my mill running under CNC for about 1-1/2 years and immediately saw a need for higher rpm. Should have listened to recommendations by others on this site but went the auxiliary spindle route and soon discovered that, although workable, didn't work well machining steel and end mills larger than 1/4". Good luck with your conversion and please post pictures. We're voyeurs when it comes to machinery.

Tom S.
 

Davd Flowers

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It's worth doing sooner than later. Machining aluminum with a 1/4" carbide end mill at 1970 rpm will test your patience. I've had my mill running under CNC for about 1-1/2 years and immediately saw a need for higher rpm. Should have listened to recommendations by others on this site but went the auxiliary spindle route and soon discovered that, although workable, didn't work well machining steel and end mills larger than 1/4". Good luck with your conversion and please post pictures. We're voyeurs when it comes to machinery.

Tom S.

I know all too well about having patience. The g0704 lacks rpms as well, and its lack of rigidity keeps it from swinging the larger endmills I can run in my bridgeport. I added a auxiliary spindle to it, but that was for running a .010" endmill for some engraving work. I apologize for the bit of a thread derail, but offer some pics as atonement.
20161107_123933.jpg
20161206_162425.jpg
 

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TomS

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I know all too well about having patience. The g0704 lacks rpms as well, and its lack of rigidity keeps it from swinging the larger endmills I can run in my bridgeport. I added a auxiliary spindle to it, but that was for running a .010" endmill for some engraving work. I apologize for the bit of a thread derail, but offer some pics as atonement.
20161107_123933.jpg
20161206_162425.jpg
Nice medallion! I've got a couple of hot rods. What do you have?

Here's a pic of my auxiliary spindle.

Tom S.

20151110_085830.jpg

Super PID speed controller gets me down to 5000 rpm.
20151211_114520_resized.jpg
 

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Davd Flowers

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This is my current project....
20160511_102056.jpg
20160911_135524.jpg
20160915_192230.jpg
 

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TomS

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This is my Dads, we finished it up a couple years ago.
20151213_114952.jpg
Nice cars! Really like the 40. Built a few over the years too. These are my current wheels in storage for the winter.

Built in 1996. Had so much fun in it we wore out the first engine.
20170120_130650_resized.jpg

This is the work in progress. Mechanically done. Paint and interior next on the agenda.
20170120_131205_resized.jpg
 

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TomS

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I've had my VFD and belt drive conversion running for a few months now and am pleased with the results. Speeds and feeds are now where they should be and surface finishes are improved as are machining times. Now it's time for phase 2 of the conversion: PMDX-126 BoB, PMDX-107 spindle control board and ethernet smoothstepper.

I've got the BoB, spindle controller and ESS mounted in an enclosure and currently wiring the components. Thank God for Google! Pictures to follow. One question I have is in regards to wiring my drivers (DQ860MA and DQ2722) to the BoB. I've got the step, direction and com wiring figured out but the enable wire from the driver has me puzzled. I've read the PMDX manual several times as well as the AN002 bulletin and associated flyer on whether to enable or not to enable. From what I understand the enable signal is a 5vdc signal to the driver to lock the motors in position during startup. Is this correct? If yes, then I can connect the enable wire to the PC+5V terminal at the BoB? Am I on the right path?

I'm sure more questions will come up as I work my way through.

Thanks,

Tom S.
 

jbolt

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Sorry Tom I cannot help. I don't use the enable wire on my machines. Never saw the need.

I believe you use the "PC ground" on the connector but I'm not sure how you set that up.

You might try searching the PMDX forums or posting a question. Steve is pretty good at responding.
 

TomS

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Sorry Tom I cannot help. I don't use the enable wire on my machines. Never saw the need.

I believe you use the "PC ground" on the connector but I'm not sure how you set that up.

You might try searching the PMDX forums or posting a question. Steve is pretty good at responding.
Thanks Jay. I was hoping you saw my post. Nothing on the PMDX forums relating to my question. I'll sign up and post it there.

I've got the wiring done. Next steps are to make sure the jumpers and dip switches are set correctly and double check my wiring. Then it's onto Mach and ESS configuration and testing. I'm sure I'll have more questions.

Tom S.
 
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