Precision Matthews PM-728VT CNC conversion

Just a quick update. Still no news of the mill that I ordered in Nov. Have called PM last Monday: they have received the container from Taiwan, and are going through the back orders in the order they were received. The guy on the phone told me my order will fit into this batch of mills, so I am hopeful to have my toy soon.

In the meantime, have received the complete ClearPath package from Teknic. So today I set out to wire it up on a piece a plywood; added some legs that I cut from an old closet dowel, so cabling can be tucked under. Also attached the motors to a piece of plywood so they don't flop around. After configuring the steps in the Teknic configurator, I managed to wire up one motor following the Acorn schematic. Then I added the contactor, and after I figured that out, added one proximity sensor, that can be tripped and stops the corresponding motor. Very pleased how everything worked out.

I decided I will use 6-pin aviation connectors for the gland plate of the enclosure, instead of Molex.

Still to do:
1. Get NC (normally closed) proximity sensors, instead of the current NO sensors. Small point, but worth it; in case the connection is dropped, you find out before you crash.
2. Need to find sensors that have 4 pin aviation style connectors from the body of the sensor to the enclosure. Will wait until the mill arrives to see the actual physical limitations, and see if I need 90-degree plugs or straight.
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koenbro said:
Where did you order the Molex connectors? Even though I plan to use aviation connectors for the motor controls, the motor power is a separate molex that I intend to keep.
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I buy them from Digi-Key.
 
koenbro said:
Hello everyone, I have an order on a PM-728VT and is due to deliver within a month. I will do a CNC conversion (with the PM mechanical kit), and will document it here, while also posting the myriad questions that are certain to come up. I am planning to weld up a base for it that will incorporate a toolbox that I already have. I am garage hobbyist and plan to mill aluminum and mild steel mostly.

My experience is with an Avid CNCRouterParts 2x4' extrusion based router that I built, using a 2.2kW air cooled spindle driven by a Delta VFD. The motors are NEMA23 and the controller is a Warp9 ESS; I got the electronics boxes already assembled by Avid. Then I added a THC and a Hypertherm PM-45XP with a water table. I use Fusion 360 and Mach4 with SheetCam for plasma.

For the mill, I have already bought an Acorn with their CNC12 software (paid version).
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Have you started your cnc conversion yet? I just received mine and will be doing the same soon. Hopefully you can share helpful experiences on doing this. Looking forward to following your thread.
 
Not yet. I have not yet received the mill and the CNC kit. I have ordered some accessories (vise, collets) and they (QMT/PM) are still waiting for the vises to arrive. Was told it's next week. The mills are already in, but won't ship until the whole order is complete.

Thus far I have configured the Acorn, the motors, 3 sensors (will mount either 3 or 6, and decide once I have the mill), the e-stop, and the contactor. Will still need to buy an enclosure, for the electronics, but want to see what size fits and where, etc.

I am also considering building an enclosure for the mill out of 1010 series 8020. Again, cannot proceed until I have the mill in hand.
 
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koenbro said:
Not yet. I have not yet received the mill and the CNC kit. I have ordered some accessories (vise, collets) and they are still waiting for the vises to arrive. Was told it's next week. The mills are already in, but won't ship until the whole order is complete.

Thus far I have configured the Acorn, the motors, 3 sensors (will mount either 3 or 6, and decide once I have the mill), the e-stop, and the contactor. Will still need to buy an enclosure, for the electronics, but want to see what size fits and where, etc.

I am also considering building an enclosure for the mill out of 1010 series 8020. Again, cannot proceed until I have the mill in hand.
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thanks for the reply. Could you share a ballpark figure of cost for the electronics you already have? I think your idea for an 80/20 enclosure for the mill is a good one.
 
The ClearPath package was 1,800. I chose the upper tier motors (enhanced option and shaft seal), but did not go crazy on power; chose CPM-SDSK-3421P-ELS and CPM-SDSK-2321S-ELS. You can save $70 on the NEMA34 and $120 on the NEMA23 (2x$60) from going with motors without the enhancements. If I were to do it again, I might get the one long motor control cable, as I cut off the molex on the acorn side anyways -- so you could shave off a few more dollars if you are familiar with cables (I was not). Would not cut corners on the power supply. In summary, Teknic has a serious product and there are real people behind it, whom you can call on the phone; I would 100% choose Teknic again over some overseas ebay solution.

The acorn package was 299, and that is the absolute minimum you need. I went ahead and ordered the "Pro" mill software ($159), the e-stop button (Made in Italy, superb quality, MUCH better than the one I got with the Avid CNC RouterParts package; thinking of getting a second one for the router) for $45, and the Wireless MPG CNC control pendant for 299. So my total was ~800. Could have stayed with the Mach4 that I already have and get an ESS, but my intuition is that the acorn is a step up for the mill, and it plays nicely with the ClearPath motors.

Got three inductive sensors for $3.60 each off ebay. In fact I ordered three fancy Contrinex sensors from Automation direct for 15/each with nice M12 cables, but picked the wrong sensors that don't work with the acorn. Also got a Made in Germany Eaton DILM32-01 contactor off ebay for 35. Still don't have an enclosure.

So the minimum is about $2,000 ($1600 for the motors + PS, and 299 for the Acorn). My setup is ~2,700 with a few extra conveniences and luxuries.

Still waiting for the mill, though. Hope this helps, and apologies for the delayed reply,
 
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I have just been notified by PM that my mill is on its way! So hopefully will be in my hands soon. First, will build a base for it, then do the CNC conversion.
 
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