New PM-728V-T Mill

[jimrk]

Setting the C86ACCP does the job for when e-stop or if there is a servo fault. Of course when the power is turned off the head needs to be locked or a support needs to be used.

Not sure if I can give them any helpful info. I don't know if the tuning software saves any info that would help. You could ask them.

 

[koenbro]

Setting the C86ACCP does the job for when e-stop or if there is a servo fault. Of course when the power is turned off the head needs to be locked or a support needs to be used.

That is helpful, so I went ahead and ordered the C86ACCP. Meanwhile on the other discussion, I am talking to the Teknic engineer I mentioned. I am closing in on the servo choices.

 

[kiloseven]

@jimrk Following your conversion with great interest, as I have an order on a PM-728 with the PM CNC conversion kit and hope to see it delivered within a month. I bought an Acorn and am considering ClearPath servos (as DMM) and am struggling in choosing the specific motors. Saw in your earlier post that you went with the CPM-SDSK-3432S-RLN for the z Axis. Are you satisfied with its performance? Do you have any recs for NEMA 23 (the PM conversion kit requires NEMA 23 for the x and y axes) with sufficient torque to mill steel?

Hi koenbro,
I used NEMA 34 sdks-3421's for the x and y axis . I use one separate IPC-5 for the Z ( CPM-SDSK-3432S-RLN). and a (CPM-SDSK-2321-ELN) for the A axis. The A axis is nema 23 clear path. And a separate IPC-5 for the X and Y axis's. The performance with The Acorn board is Very good. The mill is never lacking for power. I have the Nema 34 mount fusion files if you would like them. I would be easy to mount Nema 34's to the X and Y. Albeit it cost more now , I justified the cost based on performance needed for heavier cuts. Faster material removal. I use the CPM-SDSK-2321-ELN
on the 8K SouthBend Lathe with the Centroid Acorn Control. Very accurate and consistent. Let me know if you would like the Fusion 360 file for Nema 34 mounts . I built the the kit my self using 20mm double ball screws and 7075 T6 for all mounting. Seems to be very robust for a Small mill like the PM728VT.

 

[jimrk]

Hi koenbro,
I used NEMA 34 sdks-3421's for the x and y axis . I use one separate IPC-5 for the Z ( CPM-SDSK-3432S-RLN). and a (CPM-SDSK-2321-ELN) for the A axis. The A axis is nema 23 clear path. And a separate IPC-5 for the X and Y axis's. The performance with The Acorn board is Very good. The mill is never lacking for power. I have the Nema 34 mount fusion files if you would like them. I would be easy to mount Nema 34's to the X and Y. Albeit it cost more now , I justified the cost based on performance needed for heavier cuts. Faster material removal. I use the CPM-SDSK-2321-ELN
on the 8K SouthBend Lathe with the Centroid Acorn Control. Very accurate and consistent. Let me know if you would like the Fusion 360 file for Nema 34 mounts . I built the the kit my self using 20mm double ball screws and 7075 T6 for all mounting. Seems to be very robust for a Small mill like the PM728VT.

I would be interested to see what your mounts look like compared to mine. I like that you used 20mm screws also. Did you do your own X ball screw mount or do like I did?

 

[kiloseven]

I would be interested to see what your mounts look like compared to mine. I like that you used 20mm screws also. Did you do your own X ball screw mount or do like I did?

Firstly this is the Nema 34 mount link https://a360.co/3p8Uawr .This could be an adapter to a Nema 23 mount. The mount than I used was much thicker than the mount in the link. I did build my own mount. basically just like the original lead screw mount only Thicker with a stand off to the the nema 34 mount . I won't be sharing this drawing due to lack of sales that may incur . . It works so far. Drawings may follow. Have fun.

 

[koenbro]

Firstly this is the Nema 34 mount link https://a360.co/3p8Uawr .This could be an adapter to a Nema 23 mount. The mount than I used was much thicker than the mount in the link. I did build my own mount. basically just like the original lead screw mount only Thicker with a stand off to the the nema 34 mount . I won't be sharing this drawing due to lack of sales that may incur . . It works so far. Drawings may follow. Have fun.

Thank you for the fusion model, I've imported it into my library. I will likely get the NEMA 23 for axes x and y because the PM conversion kit is sized for 23. However will need to lay my hands on the kit first to see if the upsizing is easy/hard/impossible.

 

[kiloseven]

Given the length of the shafts on Teknic Servos I don't see a problem in mounting and Nema 34 adapter plate to the Precision Matthews Nema 23 Mount. Adjusting the thickness of mount for proper engagement of the shaft to coupler. Not impossible , but very much do able. The Ball screws in the PM drawing appear to be double nut. I chose double nut on all the axis .The design Precision Matthews chose for their cnc kit is all too familiar. Simple, and if I'm not mistaken not made of aluminum. Although 7075-T6 is very sturdy, which is what I used. Just to chime in a previous post, there are options for brakes on Teknic servos , Z axis would benefit . I haven't had any trouble with creep.

 

[jimrk]

Firstly this is the Nema 34 mount link https://a360.co/3p8Uawr .This could be an adapter to a Nema 23 mount. The mount than I used was much thicker than the mount in the link. I did build my own mount. basically just like the original lead screw mount only Thicker with a stand off to the the nema 34 mount . I won't be sharing this drawing due to lack of sales that may incur . . It works so far. Drawings may follow. Have fun.

I was asking about the ball nut mount.. as what I showed back a few pages
https://www.hobby-machinist.com/attachments/2-jpg.327843/

How do you brake the servo without any power?

 

[kiloseven]

My X axis ball nut mount is basically the same. The Servo brakes using a relay that activates when power is removed. Relay opens under power and closes the brake circuit when power is removed. In theory using the fault circuit of the servo could be used to trigger a "no holding power event"

 

[koenbro]

The Servo brakes using a relay that activates when power is removed. Relay opens under power and closes the brake circuit when power is removed. In theory using the fault circuit of the servo could be used to trigger a "no holding power event"

Is this relay and brake built in into the servo, or is it a separate piece of hardware? Can you pls clarify and provide link to hardware if appropriate.