Machine not moving smoothly

I am trying to finish up my build, but I’m having trouble getting it to move correctly. Especially when doing longer movements, the X and Y axis sometimes stall for a split second instead of moving smoothly. Because of this, the movement is not reliable and a p.e. 200mm movement ends up being 195mm. Or something along those lines. I tried tensioning the belt better, making sure the pulleys aren’t slipping, adjusting the stepper drivers and cleaning the conduit. And while that partially made it better, the issue is still there.

It doesn’t sound to me like the stepper motors are skipping steps or the belt is slipping, so I don’t really think that is the cause.

I took a slow motion video of the issue (sorry for the flickering. I don’t have any other lights in that room):

At about 31 seconds there is a particularly bad instance of the issue occurring.

Information that might be useful:

Controller: Megatronics 2.0 (leftover from my first 3D printer)

stepper drivers: DRV8825

I have the motors wired for dual endstops, butdue to me not yet having 4 microswitches, I currently only have the Y axis (the one in the video) configured for dual endstops.

While I’m fairly confident that my printers accuracy is good enough, the tension bolts did not slide into the holes for all of them, so they do not really move. And when I put the rollers on the conduit, there was some force involved and when I held the conduit vertically, the rollers would not drop down on their own. I have since used WD40 on the ball bearings, which helped with that smoothness. All bearings touch the conduit and turn when parts are moved.

With the current state of the assembly, I can move the gantry around by hand fairly smoothly, but it does require a bit of force. I’m not sure how much force should be normal? Before actually putting on the belts it definitely required less force (which probably makes sense, since now I have to get the motors to turn when moving it by hand).


I’m not sure what I should try next at this point. If the issues are because the rollers and gantry are putting too much force on the conduit, I would expect it to stall due to skipped steps or the belt slipping, but as I mentioned it doesn’t sound like that is happening. Hopefully somebody here has an idea as to what I could try to troubleshoot this.

I know you said it’s not skipping steps or belt slipping but also check the pulley on the motor shaft.

I can barely see the stuttering in the video, but the tape appears to rotate smoothly.

Another thing you could try is to draw the crown. It won’t come out great but the look of the artifacts might give more of a hint.