Having trouble with first layer PETG
So I'm fairly new to 3D printing, but I've had a Prusa i3 MK3S+ built for a few weeks now printing mostly PLA (smooth sheet), and a handful of PETG prints (textured sheet). So far, out of my first ~30 or so prints in either materials, I never really had any problems. Recently, I decided to build the Lack Enclusure and was printing through the printed parts set. I've gotten through about half the prints with no issues at all. However, once I got to the file prusa_mmu_enclosure_5_02mm_pet_mk 3s_16h45m.gcode, all hell broke loose on my first layer. I can't seem to get the rafts to stick to the sheet well, the nozzle seems to randomly extrude clumps, and every time I print, lines of the rafts start coming up and end up causing a blob on my nozzle -- some prints are much worse than others and they do not all fail in the same place, but all of my attempts at this print have so far failed.
Things I've tried:
- Cleaning the nozzle thoroughly with a wire brush
- Cleaning the textured sheet with 99% IPA
- Re-calibrating the first layer height (many times)
- Calibration wizard
- Cold pull
- Switching to a new spool of PETG
- Switch back to PLA, having a successful print, then going back to PETG
However, nothing seems to help the strands of the raft actually stick! After all these things I've tried, if anything the prints have gotten worse, and certainly not better. I'm running out of ideas and could use any advice anyone can give.
I've attached some photos of the results of some of the recent attempts (sorry for the glare!). Does anyone have any ideas for things I could try?
Best Answer by Eric E:
If the textured sheet with PET-G worked before, and now, with nothing changed...
Wash your sheet with soap and hot water. Good scrubbing, behind the ears and everything
Seriously. That is your problem. It is that simple.
RE: option
Supports are very sensitive to z-offset and the bed being clean. If you have ruled these out, consider a spray of hair spray (Aquanet).
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Chuck H
3D Printer Review Blog
t
Did you do the first layer calibration with PETG? Kind of looks a bit low on these pictures. PETG likes to have a bit more distance from the sheet than PLA. Always hard to tell from pictures but to me it looks less like lack of adhesion but more like filament being pulled/pushed off. PETG takes every opportunity to stick to itself or the nozzle or the heater block, so more so than PLA it's important for nozzle and heater block to be squeaky clean.
Soap and water
If the textured sheet with PET-G worked before, and now, with nothing changed...
Wash your sheet with soap and hot water. Good scrubbing, behind the ears and everything
Seriously. That is your problem. It is that simple.
Don’t trust forum advice.
Perfect!
If the textured sheet with PET-G worked before, and now, with nothing changed...
Wash your sheet with soap and hot water. Good scrubbing, behind the ears and everything
Seriously. That is your problem. It is that simple.
Wow, you saved me! I cleaned the thing a few times with IPA as per the manuals, but I only saw soap & water mentioned in a few random forum posts that I didn't think to trust over the manuals. I figured soap & water wouldn't do anything better than IPA. Well, after a thorough clean with some dish soap & hot water, the print is sticking perfectly. Thanks so much!