Prime tower first layer issue

Snapmaker J1/J1s
1

Good day fellow J1 users,

I’m having a strange issue with the first layer of the prime tower.

I’m using Cura 5.6.0 and the affected step seems to be the ‘brim’ or ‘base’ part of the prime tower. When printed, the first layer of the prime tower seems to over-extrude.

The contour of the prime tower is fine and the skirt is is perfect.

Below is a picture of a small test print of one layer. On the left is the prime tower and on the right is the print model for the purpose of testing.

IMG_4418
IMG_44181920×1440 478 KB

As you can see, the model prints perfectly flat but the prime tower doesn’t.

What I’ve tested so far without success.

  • Did bed level calibration.
  • Moved the prime tower to a different spot on the bed.
  • Changed Prime Tower parameters in Cura.

Here is the Cura project file.

I’m looking forward for any suggestion.
Cheers

2

I’m not a J1 user, but have the Dual Extruder head for the Snapmaker 2.0, and in my prints the prime tower first layer does not look perfect as well. I just took it for granted, and did not bother, assuming that the prime tower is most likely optimised for nozzle priming, and not for looking nice. My prints went through, the prime tower did its work, no problem for me. Also using Cura btw.

3

Thanks for sharing your experience. In my case, because of the curls, the hot-end of the right extruder is strongly hitting the base of the prime tower. The right extruder z-height is accurately calibrated.
My print did complete successfully though. However, I have the feeling it could fail because of that and/or it could de-calibrate the z-height or the bed level.

4

Brief update:
I could narrow down the issue to the Initial Layer Line Width which is set to 150% on J1’s default profile.
Setting it back to 100% solve the curling/over-extrusion issue.
It looks like a Cura bug to me as both Flow and Line Width are reported correctly in the preview. Maybe the Line Width is not honored for the Prime Tower Base while the Flow is. That would result in partially overlapping lines on the first layer of the Prime Tower Base.

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