Layershift galore or what?
I was ready to take the printer from testing to production and I got a failed print, printing a large flat print in PETG (can not show due to restrictions) I got a 25 mm shift in both X and Y. I tested a smaller print and it was fine. I decided to print a toy for my son. I used Prusament Galaxy Black PLA, standard printer, printing and filament profiles for the correct printer, extruder, and filament. Using:
0.20mm SPEED @COREONE HF0.4
Prusa CORE One 0.4 nozzle
Prusament PLA @COREONE HF0.4
It seems like the shift is increasing with size of the print. it occurs equal in X and Y directions, as if it tries to print a shadow. It is always to the left and away from the door. There is nothing wrong with the print before the shift, and apparently nothing wrong after the shift, besides the shift it self...
I have checked all components of the XY gantry, the belts, all idle pulleys, gears and screws. Everything checks out. I build the printer from a kit as instructed. I passes all the self testing and "sometimes" produce incredible prints but not always!
Please examine the included image
I am running 3.6.2+10364 firmware, with Prusa Slicer 2.9.2
Please advice what could make this happen? I am out of idéas! I think I have covered everything and checked everything that could be wrong.
Thanks in advance
/Mike
RE: Layershift galore or what?
Well after som extensive testing and analysis of the said problem I have come to the conclusion to what the problem is and the solution is simpler than you might think. the solution also solves my earlier post Resonance at a certain speed.
It seems that the belt tensioning is the culprit. I followed suggestion in the Prusa app on iOS and tuned both X and Y belts to the optimum 85 Hz +/- 1 Hz. This made the motors resonate at 80 mm/s as well as skip belt teeth when accelerating fast and over longer distances. Hence the increase in layer shift on large prints. Why X and Y is equally effected is due to the design of the XY gantry. To maintain the position in X moving Y, X motor actually also moves. The same is true for maintaining the Y position moving X.
Solution: Was tuning both X and Y belts to 90-95 Hz. It solved the shift and the resonance. I can now print at speed without any problem. I anticipate that the wear and tear of the belts are increased and even shortens their lifespan, but I can print so...
Happy printing!
/Mike
RE: Layershift galore or what?
Thanks for sharing your solution!
I've printed a round vase, or rather tried, and it shifted about 30 mm towards the front, a few layers after going from the bottom shell to only printing circles.
Seems to be a similar issue, since there were no traces of the nozzle hitting the print or anything.
I had to re-tune the belts due to the Y-Axis Homing position having a ~1 mm gap to the end-stop and they're now at 81/86 Hz and the vase came out fine.
First make sure your print sheet is perfectly clean and that you are not printing in a draft because a common cause is a minor head crash when a part lifts off the bed and this may be due to fingerprints on the sheet or to thermal warping.
Cheerio,
RE: Layershift galore or what?
Thank you @diem
First make sure your print sheet is perfectly clean and that you are not printing in a draft because a common cause is a minor head crash when a part lifts off the bed and this may be due to fingerprints on the sheet or to thermal warping.
Cheerio,
I am using IPA before every print to get alla grease away. It is very hard to print PETG with grease, PLA is more forgiving.
I found a solution to the problem and after more printing I can say it works like a charm. I am running with a tension that results in a belt frequency of 93 Hz. No skips and no shifts even at a higher speed than the test prints earlier.