Has anyone created a 3D model of the PM-728vt? I see cad models of the G0704 and the PM-25 out there. It would be great to have a Fusion 360 model of the 728 to work out things like limit switches, encoder mounts, stepper/servo mounts, etc. Great work on your build, by the way.
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New PM-728V-T Mill
- Thread starter AlanB
- Start date
Congrats on getting the spindle speed worked out. Is your solution similar to what Franco did? How did you hook up the relays to switch on/off or fwd/rev? Also, it looks like you have an AC line filter in your cabinet. Do you stick that on the very front end of the AC coming into the box? I've seen those on VFDs before, but I didn't realize we should also include them in a non-VFD setup. Thanks for posting.
yes to what Franco showed. You can download his diagram from his drop box. Just has 3 wires from Acorn relay board and the 2 from the KB board going to the PM control board. PM now has a board listed to do the same but who knows when it will ship.
I used the filter on my G0602 VFD so just added it here just because
And I think Clearpath suggested it for their power supply.
I used the filter on my G0602 VFD so just added it here just because
And I think Clearpath suggested it for their power supply.- Joined
- Feb 23, 2016
- Messages
- 483
@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?
Very happy with the Z axis. Seems to have plenty of power. Have added weight of the PDB without any strain. The one downside of the servo is no holding power when disabled. I use the Z gib lock, easy to forget 
Even when locked I can jog the head up and down. For the X and Y I used CPM-SDSK-2321S-RLN. Been happy with them also. Have not done any steel but should be just fine.
Even when locked I can jog the head up and down. For the X and Y I used CPM-SDSK-2321S-RLN. Been happy with them also. Have not done any steel but should be just fine.- Joined
- Feb 23, 2016
- Messages
- 483
Much appreciate the reply. I was wondering about braking the z axis to prevent it crashing down. You mentioned earlier that the C86ACCP Clearpath Connector Board has a setting for hardware or software enable, and that switching it to the hardware setting solved the issue. Do I get that correctly?
I am in contact with one of the Teknic engineers who offered to run a motor simulation of the PM728 to find the optimal servos, but he needs input parameters, some of which I cannot provide (have no clue on how to even get a range of reasonable upper/lower bounds), such as speed and acceleration requirements) for worst case moving load weight on each axis.
I am perfectly happy to order the servos that you and other users have found to be satisfactory, and I am confident that they will get me within 80% of what I need; meanwhile the extra info needed to refine this to 90-95% may be unavailable. So life is imperfect and decisions sometimes have to made with incomplete information, and I am comfortable with that. Before I pull the trigger, was wondering if you or anyone else can provide these estimates? If not, I'll just go forward and order the motors you specified (and the C86ACCP board).
I am in contact with one of the Teknic engineers who offered to run a motor simulation of the PM728 to find the optimal servos, but he needs input parameters, some of which I cannot provide (have no clue on how to even get a range of reasonable upper/lower bounds), such as speed and acceleration requirements) for worst case moving load weight on each axis.
I am perfectly happy to order the servos that you and other users have found to be satisfactory, and I am confident that they will get me within 80% of what I need; meanwhile the extra info needed to refine this to 90-95% may be unavailable. So life is imperfect and decisions sometimes have to made with incomplete information, and I am comfortable with that. Before I pull the trigger, was wondering if you or anyone else can provide these estimates? If not, I'll just go forward and order the motors you specified (and the C86ACCP board).