Repeatable Z-Axis Issues

[webzoid]

I received my Snapmaker Kickstarter reward yesterday and after the excitement of setting up and printing my first calibration cube, I’ve been a little disappointed with the results of some slightly larger prints.

I believe there is an issue with the Z-axis of my Snapmaker, whereby when the print head gets to a certain point, the Z-axis seems to shift (or drop, I’m not sure) but it causes part of the print to deform.

Here are some pictures to highlight what I mean. As can be seen, this artifact is repeatable - every time the z-axis gets to a certain height, this happens to the print:

Is there anything I can do manually, which would help eradicate this? Could it be a faulty/badly machined ball screw?

Thanks in advance.

[Tone]

You could try swapping it with one of the other actuators. Maybe one of the other ones would perform better. The unique thing about the Z axis is that it has to handle the load of the Y-axis actuator plus the print/cnc/laser module.

[webzoid]

Thanks, that’s a good suggestion. I’ll give that a try tomorrow.

Just seems odd that it happens at exactly the same position every time. I’ve also noticed a sticking point on the X axis but thats far over to the left and may not be too much of a problem.

Will post back with my findings.

[Tone]

Are your cables restricting movement?
The aluminum extrusions could have a defect in the race way that is causing it to stick at that location. With the snapmaker turned off, you could try manually moving the axis in that region and see if it has resistance at that point or if the movement is fairly uniform.

[webzoid]

No, the cables allow free movement for all axes - the cable arrangement isn’t nice but definitely not restrictive.

I tried “jogging” the Z axis and movement was smooth all the way along the screw. I’ll also try this manually on all 3 axes to see if there is any resistance.

Thanks for your insights.

[CthulhuLabs]

Have you followed all the tips here:

Recommendations For Successful Prints

A couple more suggestions: a. Open the end cap on each linear module opposite the end with the cable and apply Loctite 243 to the screws that hold down the plastic lead screw retainer. There have been reports of these screws working loose and causing print quality issues. Mine were not very tight from the factory. b. Use Loctite 242 or 243 on all other screws except the thumb screws and function module mounting screws to make sure everything remains securely assembled.

If so please take a test cube model and elongate it in Z past the point where this is happening. Next slice it in vase mode. You just want the outer perimeter printed. See if the issue still happens. Report back with your results.

I have a feeling this isn’t an issue with Z but instead extrusion issues.

[webzoid]

I’ll open up the end caps and check for tightness and Loctite them where necessary. If there was any looseness, I would expect to see markers during any stage of the printing process, not just at one certain height.

I will give the elongated cube a try also and, like you’ve said, I’m also now not so sure its a Z axis problem having thought about it a bit more.

Will report back later today.

Thanks.

[DANIEL.ZHOU]

I have encountered this problem before, and then changed the sink screw, the problem has improved a lot.

You can have a try

[CthulhuLabs]

The link only showed the last comment from that thread for some reason. I list like 15+ things in the original post you should check out.