The snap seems to happen when the CNC is warm and tends to appear in approximately the mid point of the movement but it’s not the exact same place each time. I am also having a little X-axis wandering on some of my laser engraving runs but I think that may be due to me running it too fast. I slowed down to 3,000 mm/m and it appears to be much straighter now.
@acruther can you kinda pinpoint where the sound is coming from?
Thanks for the quick reply. Best guess is the Z axis assembly. Could be the ball screw above the assembly.
@acruther if you do an air carve, does it still do it?
Yes. At the moment I’m working on a laser engraving task though. I don’t think it’s affecting the movement much as long as I don’t run it too fast. I was running it like 15,000 mm/m when I saw the real drifting. Didn’t realize the max was 12,000 for the machine. Regardless I had to slow all the way down to 3,000 which seems to have resolved the drifting issues.
@acruther Did you check all your couplers? It’s part of the regular maintenance.
It seems you are running an Altmill. The Altmill uses a closed loop stepper system and drifting should never happen. If there is drifting it would likely be caused by some sort of mechanical malfunction unrelated to the actual movement (ie a loose coupler is an example). If you are running the mill too fast so the motors can’t keep, you should get a fault notification and the mill should be shutting down.
Thanks for the replies…sounds like I need to check the couplers. I have never checked them. I probably only have 80 hours in though. I have hit things a lot like a newb…
Here is the worst example of the drifting. There is a lot of testing going on here but the faded picture at the bottom which is badly drifting to the right is the worst example. I believe this was 15,000 mm/m.
This one you see much more subtle drifting at the top. Doesn’t really distort the overall picture. Think this was like 5,000 mm/m.
This one I think is perfect at 3,000 mm/m.
So I removed and reinstalled the coupler but it seemed fine, bottomed out and everything. I resintalled. I then loosened the bearing blocks per this guide:
So far hasn’t fixed my issue. Could this be a problem with the stepper motor?
Well it could really be a whole bunch of things. The position feedback has to arrive from the motor and that could be wonky (could for example be a loose feedback sensor/wheel). The controller could be defective as well. Neither of these have been reported before but yes, it could happen.
I think your best bet at this point is to raise a ticket with Sienci Labs.
If you are impatient, you could try switching the X axis (I assume that is the axis in question) motor with one of the Y axis. That would eliminate the motor is a source of the issue (or confirm it).
