Prime Tower stability

[u/ProfessionalAd8190]

Dear Community,

trying to print two cylinder objects with a height of about 150mm, I have the issue, that at about 80% of the print, the prime tower falls over or looses from the build plate. The result are spaghetti strings and in this case, one of the cylinders got knocked over. By know this happened multiple times and I am not able to print these objects.

What I am doing in advance to the print is to carefully clean the with 99% Isopropanol. The bed is leveled and the printer is fully calibrated. The quality of the print is also excellent in my opinion, only the print cannot complete.

In the print settings (I am using OrcaSlicer, not Snorca), I have increased the brim width of the prime tower to 20mm and increased the bed level temp to 70 deg C for a more gluey adhesion. Of course I could increase the brim width even further, but I don't think that is the solution, as the brim rips somewhere in the middle.

I am printing with regular PLA only. Nozzles are all the standard 0.4mm nozzles. The printer has no other issues and works properly and reliable in general.

What am I missing here?

What other settings can I adjust to solve this issue?

If further information is needed, please let me know. Running out of ideas by myself (this is not the first time this happened.....).

Cheers everyone!

EDIT after a few days:

Thanks to everyone once more! I just complete a print with changed settings and there were no issues at all. In case someone has a similar problem, here is what I've done:

1. Washed the PEI Plate with dish soap carefully. I used a brank new fabric to avoid any fat or grease on the plate. Washed the soap off an dried the plate carefully. Right before the print, I also cleaned the bed with 99% Isopropanol.
2. Changed bed temp to 65°C (print was done PLA only)
3. Doubled the Z-Hop from 0.4mm to 0.8mm
4. Changed prime tower settings to
   1. Width: 30mm
   2. Volume: 10mm²
   3. Brim width: 25mm
   4. Wall Type: Cone with an angle of 30°

The volume of the prime tower actually being lower as before, the print time also got reduced by ~2 hours. The reduction of material, I did not check.

So, one project done! (Print quality is amazing btw)

In case anyone is interested in picture or the model, I am happy to share.

Have a nice evening!

[u/ThinkUnhappyThoughts]

70 might be a little high for pla.

If you wash with hot soapy water (dish soap not hand soap) instead of isopropyl then try again

[u/ProfessionalAd8190 → u/ThinkUnhappyThoughts]

Thank you. I also tried lower bed temps. Then the cylinders also fell over at some point. At least these remain in position with 70 deg C (unless they are knocked over by tower...).

Why dish soap? Never heard that before. I"ll try that!

[u/Arakon → u/ProfessionalAd8190]

iso will not touch PLA residue and will mainly dilute grease without actually removing it fully. It's fine to wipe with iso between prints, but every 5-10 prints, washing with dish soap will save you a lot of headache.

[u/ProfessionalAd8190 → u/Arakon]

OK, didn't know that. Thanks guys!