Layer separation  

RE: Layer separation

as a reference to what the print is supposed to look like

I suspect you have two issues interacting ...

Poor adhesion due to warping and perhaps a poorly cleaned print sheet or uneven glue spread. Show us the underside of a failed print to confirm.

Wet filament.  Dry it and you should reduce stringing and some extrusion issues.

So:  Dry the filament.  Treat the print sheet with care and perhaps add a brim to aid adhesion.

Cheerio,

RE: Layer separation

Hi Diem, none of what you mention is the issue. This is not a bed adhesion issue but a Layer shifting issue. I see that others have had this exact same problem and I have read up on what they suspect their cause/s might be. I had "avoid crossing perimeters" set to off. But "Arc Fitting" was on and have turned it off and will try reprinting. After the first time this issue appeared, I checked my belt tension, it was @58hz (not surprising since probably do to initial stretch of the belts since they are only a week old) so I tightened to recommended 85hz and re ran the print: same thing happened again. I'm now going to check my grub screws on my servos and will run another print to see if the "Arc Fitting" or problem with grub screws is contributing to the issue.

Poor adhesion and/or warping allows one side of the print to rise into the head-path causing the sort of crash that leads to layer shifting.  Marks on your print sheet suggest that something has moved...

Show us the underside of a failed print to confirm.

Dry the filament. Treat the print sheet with care and perhaps add a brim to aid adhesion.

Cheerio,

RE: Layer separation

This print shifted earlier than the previous (see attached) Again I don’t think it is an adhesion problem - it is a sudden shift of my X/Y. This print after I check my belt tensión equal for both X and Y at 95hz. Arc fitting and avoid cross perimeters are disabled. I have yet to check my grub screws on my servos. I will do that next.

RE: Layer separation

Here  is a view of the previous print underside

RE: Layer separation

And a side view

RE: Layer separation

UPDATE:  I found that my Y calibration has failed. It is because when the gantry is pulled all the way forward, the left side stops before the right side. Need to correct. I also discovered that my Y Servo pulley was riding a bit high, and I've adjusted it so the belt rides centered on it.  Unfortunately, I broke my idler pulley tension  (did not loosen belts enough) when trying to correct the gantry. Need to print another one on my Mk3. 

Quite a lot of lifting on both, the one on the right is worst.  Put a straightedge against the print and you'll see.  It only has to lift two layer heights to crash.

ASA is always liable to warp so the brim suggestion is seems correct. Make sure the ventilator is closed.

The walls of the print might be better but there is no sign of uneven belt tension and the first layer calibration looks good so I doubt there is/was anything wrong with the mechanics or settings.

Cheerio,

RE: Layer separation

So, I have my Core One X/Y calibrated and belts are at 85 hz. Gantry is 90 degrees. I do have "Avoid Cross perimeters" turn off - but with the speed setting I still get layer shifting.

I printed a benchy with the same settings that the previous model exhibited layer shifting and it printed PERFECTLY.

So, my next experiment was to go from .20 Speed to .20 structural (slow down) and just finish the print it printed PERFECTLY.
This is not a hardware issue but a software issue. with these particular models (cylinder shapes), I will not be able to use the speed setting.

Shame - that is why I purchased the Core One. I guess going too fast gets you into trouble...