Middle layer gap and some small "explosion" holes in print
I've recently got an MK4S and have had several successful prints in PLA, PETG, ASA and PC Blend.
However, PETG prints had always had a less smooth finish with some layer variation here and there (by that I mean a layer that sticks out very slightly or is very slightly more recessed) but nothing that I would call a failed print or even bad quality finish.
Yesterday I tried printing a larger model and a single layer in the middle has a gap and some strings sticking out. While the rest of the model looks mostly fine (perfect base layers, quite smooth finish overall), there are some small "exploded" holes here and there with material that looks like it was expelled from the hole.
What could the cause be? Any idea how to troubleshoot the issue?
This was printed with 0.20 mm layer height structural profile, with the stock profile for prusa PETG using a brand new spool.
RE: Middle layer gap and some small "explosion" holes in print
If someone comes here with similar problems, this is how I solved the issue.
First I tried drying the filament but that did not improve anything. There are three things that did fix of significantly improve the results:
- Switching to a high flow nozzle completely resolved the issue
- Keeping the regular nozzle but slowing the print speed to 50% minimized the issue (only a few small holes, barely noticeable)
- Switching to Prusament Galaxy Black while keeping all original settings (100% speed and the regular nozzle, stock profile) also minimized the issue (only a few small holes, barely noticeable)
So maybe the issue is linked to lower quality of this particular filament (Prusa Turquoise Blue PETG) since results with the same settings were much better with the Prusament... In any case the high flow nozzle gives perfect results with both filaments!
RE: Middle layer gap and some small "explosion" holes in print
Hi, I'm having the same issue, I'm using MK4S, Prusament PETG profile in Prusaslicer, highflow nozzle and Galaxy Black Prusament. Only thing thing I haven't tried is slowing down the print. But damn, how is that possible when everything withing Prusa ecosystem should be perfectly optimized?
how is that possible when everything withing Prusa ecosystem should be perfectly optimized?
That's not quite how it works - the presets are fairly safe, conservative setting that will work in most cases - and if you need greater precision all the configuration parameters are open.
BUT
Very often a particular model will have geometry that challenges the standard assumptions or a misguided user may attempt to print a download optimised for a different polymer...
Show us a picture of your issue and for detailed advice save your project as a .3mf file
Files > Save Project as
Zip the .3mf and post it here. It will contain both your part and your settings for us to diagnose.
Cheerio,
RE:
These are not special parts I think. I'm having issues printing PETG with other parts as well meanwhile PLA works just fine. I was thinking about nozzle partial clog, but that would affect all materials. To me it seems like the Prusament profiles in Prusa slicer are not tuned for my MK4S.
At what temperature are you printing? I have never seen the point of high flow nozzles as speed benefits only occur on larger prints and with some filaments they need a few degrees higher temperature.
Cheerio,
RE: Middle layer gap and some small "explosion" holes in print
I'm printing Prusament PETG at 255°C. Well, it's the one I got from Prusa with MK4S upgrade, so I use it
... and how are you drying your filament?
Cheerio,
RE: Middle layer gap and some small "explosion" holes in print
I'm using Sunlu S2 dryer, 55°C, 8h. But I'm not sure if I have dryed this specific spool. Is this what undryed filament can do?
It could be moisture or slight undertemperature or both. But these are usually the secondary signs - moisture is harder to diagnose from pictures of galaxy filament as the speckles can be confused with the actual water explosion pits that are clearer with plain filament.
If your dryer is working OK (not just heating but also venting some of the moisture laden air) then try printing 5°C hotter.
Cheerio,
RE: Middle layer gap and some small "explosion" holes in print
Alright, thanks for advice!