Print Offset Issue

[mexfogel]

I have the N2 Plus dual extruder.

Basic Setup:
One extruder on.
Raise3D PLA; 205 temp, high quality settings, default retractions.
0.2 nozzle
0.15mm layer height.

The print is a very simple extrude (15 inches tall) Everything was going fine and then towards the last inch (60hrs of print time) suddenly a weird offset appeared. Towards the top you can start to see a wave pattern emerge. There was also a weird gap in the middle that fixed itself.

The bed is aligned and the extruders are not rubbing against the model.

Hardware error or software error? Please help.

These are photos i took while I paused the print.

After resuming the print to see what else keeps happening the print started to correct itself.

Any feedback is appreciated, thank you.

[Vicky@Raise3D]

Please help check whether the screws around the Z-axis balls screws are loose and not tight.
And a 0.15 layer height out of a 0.2mm nozzle is pretty high. Please try dropping the layer height to 0.1mm and also add a little bit of Z-hop (.05 above the layer height) to make sure the nozzle is not colliding with the part and see whether the result can be better or not.

[mexfogel]

Yes, the z-axis ball screws were a little loose, all 8 of them. I can see how that would create the waviness as the extrusion became taller and taller.

Do you think the abrupt offset could be cause by that also? It sound like it time for me to do an overall maintenance. I've changed the grease and aligned the bed with an indicator gauge that has an accuracy of 0.001mm but I haven't touched the belts. Maybe something else is slipping.

thank you. Any other suggestions is appreciated.

[mexfogel]

Hi again, I think I found the solution to the abrupt offset. I opened a support ticket and they suggested to check the X&Y couplers for damage. There was no damage but when I installed the filament sensor I routed the excess cable on top of the Y coupler and I believe at some point it must have made contact and started to jam it.

I will retry the print and see if both issues disappear.

Than you for the help and the guidance to troubleshoot the issue.

[Vicky@Raise3D]

Thanks for your update! Looking forward to your result.

[mexfogel]

Just to be clear to other readers here, I misunderstood your advice. The Z-axis balls screws are meant to be loose. not tight. I read it backwards. (English is my second language)

[Vicky@Raise3D]

Is the result getting any better with the loose screws now?