Consistently Inconsistent prints  

RE: Consistently Inconsistent prints

PLA (or ABS) is much better for doing multiple small prints than is PETg.

It's my experience that PLA will give better small details and is less stringy and oozy.

RE: Consistently Inconsistent prints

Yeah.. but my concern is the warping for heat/sun. These clips will be exposed directly to heat and sun 24/7

For thr PETG, I would maybe have a clue if it was consistently shifting. However, it is extremely inconsistent. Some prints are 100% perfect, and some shift the X, Y layer an entire inch on the last 2 layers. 

There were issues with stringing, which was solved by printing at 215/220. But now I have completely random shifting, usually the last 2 layers

RE: Consistently Inconsistent prints

Anyone got any clues?

The prints that fail, print completely fine until the last 2-3 layers.

It shifts an entire inch or more on the X and Y axis. This is a catastrophic fail that does not make sense to me. The X and Y axis are tight and seemingly no way to shift an inch in either direction, but it does on the final few layers.

Again, it happens about every other print. One print will work completely fine with a perfect print, the next one will shift on the last couple layers ruining the entire print.

RE: Consistently Inconsistent prints

Does the printer register any collisions? 

when the problem occurs?

Joan

RE: Consistently Inconsistent prints

I'm not sure about collisions, but the printer does detect a 'crash' for X and Y axis.

On one of the prints, I was sitting in front of the printer observing. Printed completely perfectly until the final 2 layers.

All of a sudden, the printer decides to shift the X axis right 1 inch and up the Y axis an inch. The bed did not move, cables not catching on anything, axis all normal and tight, simply the printer looks like it decides to want to print elsewhere. No collisions between parts.

RE: Consistently Inconsistent prints

As another note, on one of the other prints:

The printer decided to shift the X layer right about 2 mm, for a few layers in the middle of the print.

Then the X shifted back to the correct position and continued correctly for the rest of the print.

So for this print, it had a few shifted X layers in the middle of the print.

Any tips for random, inconsistent X and Y shifting? Again, every other print, there are no shifts and everything prints perfectly. This is the main issue - if it was consistently shifting then maybe I could find a solution. But it is consistently inconsistent.

RE: Consistently Inconsistent prints

Shifts that move the same distance in each direction, like the 2mm left and right, X shift, can be caused by loose screws on the motor toothed wheel for that axis

BUT...  

Your X moved right first, then back left... 

If the printer senses a Crash (Irrespective of whether a crash did actually occur) the printer will try to re home the axis and continue the print. 

If the X axis carriage has a tight spot or tight spots, these can both mimic a crash, and prevent proper homing. 

so if the X axis sensed a crash, and re homed, 2mm early, then it would continue printing 2mm to the right. 
if another crash was sensed, and the printer re homed properly this time, then the X axis would effectively move 2mm left, relative to the previous layer.

I Would check your X and Y axis for smooth movement by hand. 
If it is at all jerky, the chances are your linear bearings need lubrication

If you have not personally lubricated your linear bearings, I would suggest that you do some regular maintenance, now, irrespective of feeling a jerky movement in either X or Y axis. intermittent faults can be the very devil to find. Lubing your bearings now, may prevent issues in the future, even if it doesn't cure today's issues. 
there should have been a tube of Prusa White Lithium grease with your printer, when it was supplied. 
Good Luck, 

Joan

RE: Consistently Inconsistent prints

Thanks Joan that makes alot of sense! I'll lube the axis and make sure everything is tight. Funny thing is that i have no issues with PLA, seems that I should have issues with any material if my axes was messed up

RE: Consistently Inconsistent prints

it's one issue out of the way, when done... 

Best wishes