Precision Matthews PM-728VT CNC conversion

[adamyq]

I would not worry about backlash yet. Two-three thou will not explain what you have.

Is it possible your system is sending 8x more impulses ? It is uncanny you get 0.8" of movement when you command 0.1". I am attaching a screen grab of the Clearpath tuning setup in the hope it helps.

View attachment 403703

So I don’t even recognize this screen that you just sent, guess I have some more research to do.


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[koenbro]

Another area worth checking is this:
Acorn > setup > config > mach > motor:

The metric -> inch conversion needs that 5.08 factor. Plus the steps/rev have to be correct.


Let me know if any of these help.

 

[koenbro]

So I don’t even recognize this screen that you just sent, guess I have some more research to do.

It is the Clearpath MSP 2.0 tuning software that you have to download from Teknic.com and tune your mechanics BEFORE futzing with Acorn. Is it possible your steps/rev are off?

 

[koenbro]

Yes I am using the acorn with swissi's probeapp over on the centroid forum. https://centroidcncforum.com/viewtopic.php?f=60&t=6149&sid=0d45b3d3b0d6c1417d13925c36c32000
Even though its a "simple" atc It took about 2-3 days of cad work to design and another FULL week of work to move the motor controller box off the head of the mill, machine all the parts, wire everything and plumb the pneumatics. I am currently reading and trying to learn how to write/edit custom macros and plc programming so someday I can make carousel atc. Its a lot of work but its worth it when I can walk away from the mill and do other things while its running.

I never realized there is an ATC feature in swissi's app. Amazing!

What is the max tool count in the comb design? Five?

 

[adamyq]

It is the Clearpath MSP 2.0 tuning software that you have to download from Teknic.com and tune your mechanics BEFORE futzing with Acorn. Is it possible your steps/rev are off?

This was the ticket. I assumed the firmware came with the right pulses/rev, and I never even plugged them. I bought the USB cable with the package, but assumed it was just for troubleshooting. Did a quick check and everything appears to be spot on now.

I was reading some of the manual on the auto-tuning with it connected to the mechanical system. Have you all done that?


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[koenbro]

This was the ticket. I assumed the firmware came with the right pulses/rev, and I never even plugged them. I bought the USB cable with the package, but assumed it was just for troubleshooting. Did a quick check and everything appears to be spot on now.

Lemme guess: you were set at 800 steps/rev, which might be the factory default?

And yes you have to (auto)tune your system. If you change it (add a vise for example) you have to repeat the tuning.

 

[adamyq]

Lemme guess: you were set at 800 steps/rev, which might be the factory default?

And yes you have to (auto)tune your system. If you change it (add a vise for example) you have to repeat the tuning.

Bingo. Knew it had to be something like this.


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[koenbro]

Can anyone help me interpret the trip map for my sensor, obtained with swissi's app in a 1" bore?

 

[akschu]

Looks like I'm jumping on the bandwagon myself. My 728vt has been sitting in the corner of my shop for about a month, pulled the trigger on the clearpath servos and the acorn today. My requirements are pretty simple to start off, I just need to machine some aluminum sheet for some panels, but nothing is more than 5x8 and I didn't want to purchase a router when the money could be spent on servos.

 

[Loftfan]

Hi guys! I've just gotten my 728VT up and running and I'm working out the bugs. It's good to see that my measured backlash is similar to others experience.

After fixing a VERY loud (and jumpy) Z-axis (I had loose phase connections at my Stepperonline CL86T driver), I'm chasing down another issue with the Z-axis.

I seem to be chasing tool offsets, but that would be related to the issue detailed below:

My Z-axis doesn't return to the same position after a move, or several moves over 2 inches (~10 turns of the ballscrew). Moving 0.100" is no issue, it comes right back to the same spot, using a test indicator in a drill chuck. A 2+ inch move won't reliably come back to the same place. It could be 0.010"-0.015" off after a few repetitions, and gets progressively worse with more moves. I'll come back with what I find. Right now, I don't have a clue.