3 Axis CNC router

[JoeHarris]

Hi

Version 22 of Mach 3 is working way better! Here’s a video of my first proper little project. No issues https://youtu.be/JBjDpcFo2nk

[Neale]

Good stuff - I was happy with .028 but I doubt that there's much difference. Only key feature is whether or not it works!

[JoeHarris]

Good stuff - I was happy with .028 but I doubt that there's much difference. Only key feature is whether or not it works!

Haha yes very true. I went with 22 as it seems to be what CS Labs recommends.


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[JAZZCNC]

Hi

Version 22 of Mach 3 is working way better! Here’s a video of my first proper little project. No issues https://youtu.be/JBjDpcFo2nk

The boy's feeling it now...

[JoeHarris]

The boy's feeling it now...

[Wal]

That Hangboard's a cool little project. Very nice indeed.

Wal.

[JoeHarris]

I'm with Neale, sounds like Z is trying to move too fast.

I've had to detune my Z quite substantially compared to the X and Y speeds, the rapid upwards Z motions at the start of my cuts caused it to stall. Wonder if its something about moving a heavy spindle directly against gravity - although you'd hope that was only a small factor. It runs approximately 40% of the rapids speeds of X and Y (after correcting for screw pitch differences) and about half the acceleration. Its a 1605 running on a 3.1nm Nema 23, velocity 2m/min, 200mm/s^2 accel. Probably conservative, but works for me. Not a problem in every day life though as the travel is so much smaller :)

Regards the special cable, it requires a slightly custom job. I used a RJ11 crimper and some CAT5 to knock up one - you only use three wires. If you want I'll lend you one.

I have completed a few successful projects now, pocketing, profiling and v-carving, all without much of a hitch. But trying some 3D (2.5D) carving has resulted in my z axis behaving badly again! Part way though a roughing toolpath the z axis started moving a little erratically and then stalled a few times (I think). It moved up and started milling above the work piece. I pressed feedhold then stopped the machine, the spindle stopped but the z axis kept making jolting movements in an upward direction?! It only stopped it's mad movements when I hit the emergency stop. I am going to throttle back the motor tuning some more on Z to see if it relates to that, but it seems very odd to me that it would carry on moving after being told to stop. Has anyone else had a similar issue?

[JAZZCNC]

Don't know why it's doing this never seen it before but the reason it kept going after feed hold was because it was emptying the buffer.

Have you done a check to see if your missing steps from the pulse being on the wrong side of the edge.? If not then Zero the Z-axis and mark it's position then write some G-code so it moves back n forth several 100 times, only needs to be short moves. Make the last move go back to Zero.
If it doesn't return to the mark then you need to change the active Hi/Low in motor tuning for that Axis.

[JoeHarris]

Don't know why it's doing this never seen it before but the reason it kept going after feed hold was because it was emptying the buffer.

Have you done a check to see if your missing steps from the pulse being on the wrong side of the edge.? If not then Zero the Z-axis and mark it's position then write some G-code so it moves back n forth several 100 times, only needs to be short moves. Make the last move go back to Zero.
If it doesn't return to the mark then you need to change the active Hi/Low in motor tuning for that Axis.

Thanks Dean, no I don’t think I ever did that test on the Z axis but I did on the other two. I’ll give it a go and see, but really wanted to finish this job!

I reduced the Velocity on z from 2.5m/min to 2m/min and the acceleration from 250 to 200 and ran the roughing pass again a little slower than before and it cut to the end without any trouble (although it is hard to tell if it lost any steps as it is only a roughing toolpath). But once it was done and had gone back to zero for the tool change it kept making little erratic movements again. Could this still be to do with buffering if it is stopped for a tool change? I videoed it for a few seconds this time, if you have the sound on you can here it making little jerky moves. This was at the tool change so no g-code to tell it to move and nothing changing on the DRO. I don’t get it?

https://youtu.be/m1vlkqPeVMM


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[JAZZCNC]

No Joe that's definitely not the buffer...Lol

It looks very much like a noise issue.? But knowing your setup and the fact spindle isn't running I'd be surprised if it was.! . . . . Have you grounded the chassis.?

I'd be going over all the wire connections in the control box first looking for loose connections or stray wires. Also If you have any plug connections like DIN sockets on motor cables I'd check them out as well, in fact, chop them off and throw them in the bin as they are a pain in the arse.!!