Y Axis Stair Stepping

In the middle of a project the Y axis began stair stepping. It makes the cut going one way but will not reverse direction. As it tries to reverse direction, the motors make a loud noise as though they are trying to move in that direction but are unable, then it goes the same direction as before, but again does not reverse when reaching the end of the cut. This causes a stair step pattern on my media. There are no obstructions blocking movement and I have checked the adjustment on the tracks. When I cancel the project, I can get it to home smoothly with no problem. The problem is not in the coding. Any ideas?

Sounds like the pulley set screw is loose.

Had this very same issue last night. Both pulley screws on the right side Y stepper were loose, so only the left Y was actually moving the carriage… Blue Locktite :smile:

I also changed out my screws with 6mm long M3 socket head cap screws.

I checked the set screws of the pulleys on the stepper motorsand they are tight. If they were loose, the shaft would rotate in the pulley I believe, mine do not. changing out the screws is something I will do also, but they don’t seem to be the problem.

How deep of cut, size of bit, feedrate when the issue happened?

Cutting foam, 1/8 inch, about 3 mm

Sorry, feed rate is not very fast, but it is going in foam so it shouldn’t be a factor.

Foam? OK, not too tough then. Something is causing the loss of steps/movement…if everything is nice and tight, but not too tight, it could be the potentiometers need to be adjusted…have you done a lot of cutting with the X-Carve?

A few hours, maybe 15 hours or so. It was working well and then this problem developed. I checked the tightness of the wheels and they seem adjusted right. I thought it was fixed today but after about 5 minutes, it began the stair stepping again.

There is a thread on adjusting the current to the axis, that might be your problem since it is a new build.

I will look it up and try what it suggests. Thanks.

None whatsoever. I used 6mm long M3 socket head caps for the 2 Y and the X pulleys, as well as the acme rod pulley, and an 8mm long M3 for the Z motor pulley. All of them seated quite well, no issues with bottoming out. I had to use a 6mm for the acme pulley, because an 8mm was too long, it hit the screws that hold the Z motor plate to the Z extrusion.

I no longer feel anxious when cranking down the pulley set screws. Incredible peace of mind for very little $$

Problem solved. I foolishly tried to follow the directions for setting the power to the stepper motors and didn’t get the correct amount going to each axis. Read on forum on setting the power by the sound of the motors when doing a dry run of a project that had long runs. I knew how they should sound from my 3D printer, and so set them for close to the same sound. Have run it now for 10 hours with no glitch. Thanks to all who responded with suggestions.

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