PETG Layer... sliding?  

RE: PETG Layer... sliding?

Can you zip and upload your project 3MF? It's a bit hard to see what's going on with the black filament. 

First and foremost, what happens if you slow down? Try dialing the speed way back using the front knob mid-print. Try 50% and see if consistency improves. If so, you know it's something you can fix with slicer settings. If you still see inconsistencies, particularly with the same part printed at different orientations, it might be a hardware issue.

RE: PETG Layer... sliding?

Thank you for the response. Here is the 3MF file.

RE: PETG Layer... sliding?

The only thing I can see from the 3mf is that the issue occurs around the same area as when you are trying to print in thin air.  The holes transition from a large hole to a smaller hole such that without supports (which don't appear in your picture and aren't turned on in your 3mf) you are printing the perimeters without them attaching to anything.  This can lead to them curling up and cooling which then becomes something for your nozzle to bump into.  That combined with the 0.2mm Lift Z in your Filament override settings means and curling up (which petg has a tendency to do) its going to catch easily.

It might not be that and why only that hole and not the others ? but its something to consider.  

RE: PETG Layer... sliding?

Ugh. I turned the print over and and examined the bottom; it is warping. The most warping is happening in the corner where the "slide" occurred. Gonna add a brim and try again.  

RE: PETG Layer... sliding?

Posted by: @neophyl

That combined with the 0.2mm Lift Z in your Filament override settings means and curling up (which petg has a tendency to do) its going to catch easily.

You just blew my mind. I had no idea there was a override happening on the filament; I based my filament profile on the default Presentment PETG profile. Many people have reported it prints fine on the download page, so I am going to try doubling the override z-lift to 0.4 and see if that helps (in addition to adding the brim previously stated). I'll also see if I can add supports for the holes.

RE: PETG Layer... sliding?

Posted by: @axion

You just blew my mind. I had no idea there was a override happening on the filament; I based my filament profile on the default Presentment PETG profile. Many people have reported it prints fine on the download page, so I am going to try doubling the override z-lift to 0.4 and see if that helps (in addition to adding the brim previously stated). I'll also see if I can add supports for the holes.

One observation on filament profiles: The Prusa profiles are well tuned to specific filaments. If you're using a different filament regularly, consider creating a tweaked custom filament profile. In particular, be sure to calibrate the Linear Advance and extrusion multiplier values. Prusa has a page on one approach, and I've compiled my own notes on the topic.

The procedure takes a bit of time (15-20 minutes whenever I mount a spool from a new manufacturer or of a new type), but I find the results well worthwhile. I've found that I can get by with 0.2-0.4mm retraction, 0.4mm z-lift and no wiping with most filaments after calibration. Your nozzle snagging might be aggravated by a bit of over-extrusion if you're using another filament.

Also be sure you've properly calibrated your Live-Z and cleaned the print surface. PETG should generally adhere well to the print surface (too well if you don't use Windex or some other method to loosen the grip) without the need for brims.

RE: PETG Layer... sliding?

@bobstro I am using Prusament PETG Jet Black, so I started with the Prusament PETG profile. I have created a custom profile for each of my filaments (including this one) to include the tuned settings (Temperature, Extrusion Multiplier, etc). I have already calibrated the extrusion multiplier for this specific spool (0.91); I haven't messed with Linear Advance yet.

My Live-Z has been calibrated to the best of my ability. I have a custom Live-Z setting for both my Textured and Smooth steel sheet and I always use the Textured for PETG with no need for additional chemicals (only use Dawn and water).

BTW I use your Start and End G-Code and I love it! I check out your calibration notes to see if I can improve anything further. Thanks!

RE: PETG Layer... sliding?

Glad the notes are useful. Good luck with your calibration efforts. That's a hobby unto itself.

RE: PETG Layer... sliding?

Posted by: @bobstro

Good luck with your calibration efforts. That's a hobby unto itself.

So true, lol 😆 

RE: PETG Layer... sliding?

Any time I spend reading comments is time well spent. I almost always learn something.