My printer had some Z-axis issue. Here are the details:

When I was printing a model, the bottom of the model got bumpy edges(as shown in pic), and the height of the model was a little bit shorter(about 5% shorter).

enter image description here

I thought it might be caused by the Zsteppers/mm. But after I tweaked up the Zsterppers/mm, the problem remained. I realized that the extruder raised not enough at the beginning of the printing. So I print a small cube which hight is 2mm. And the following pic is the result:

enter image description here

Does anyone know what might cause this?

Thanks in advance.

  • $\begingroup$ First check your bed height ("leveling"). If it's correct, it's likely that the carriages on your Z rails are not square with it or that the Z rails are not parallel, causing binding. $\endgroup$ Aug 6, 2019 at 10:42
  • $\begingroup$ @R.. Thanks R! I leveled the bed. And the first layer printed good. How can I check if the Z rails are parallel? $\endgroup$
    – Tasca Qiu
    Aug 6, 2019 at 12:52
  • $\begingroup$ Measure the distance between them near the bottom and near the top. It should be the same. But it's probably more likely that the connections between the gantry/X-axis and the carriages that ride on the Z rails are either loose or tightened down with the gantry not perpendicular to the Z axis. For me, it was that the screws connecting the X-axis to the left-side (same side as Z motor) carriage were loose. $\endgroup$ Aug 6, 2019 at 13:05
  • $\begingroup$ @R.. I finally found my problem! Your answer is very helpful! My guide wheels for the Z-axis are too tight! $\endgroup$
    – Tasca Qiu
    Aug 11, 2019 at 8:20

1 Answer 1


Here are my problem and my solution. Hope this will help others.

As @R.. suggested, I checked my carriages and as well as z-axis guide wheels(I think it is called guide wheel). And I found that the guide wheels were too tight. I can't rotate them will my fingers. So I used a spanner to adjust the eccentric nuts until the guide wheels can be rotated by two fingers. Do not make the guide wheels too loose, it may cause shaking or other problem.

Since I don't know the exact name of each part. I marked them in the pics. If you know the correct name of the parts, welcome to correct me, I will edit it in my post.

Special thanks to R.. :P

Here are the pics:

guide wheels eccentric nut left eccentric nut right


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