Smooth sheet coating damaged?
I just recently got my Mk3S and have printed the following number of items per material all on the smooth sheet:
PLA - 5 prints
PETG -4 prints
All prints have been pretty small (benchy or a performance test wheel sized stuff). After printing one of the first PETG items, I noticed what I thought was a small amount of material that didn't come off my smooth sheet when I removed the print. It maybe was as small around as a pencil eraser but had almost no height -- more like a smudge. I did a second PETG print shortly after without being able to get that off, thinking it would come off when I removed that second print. That print had a slightly larger footprint and encompassed the "smudge". Those PETG prints stuck pretty hard, and when I got the second one off it looked like the "smudge" got bigger. Now it is about the size of a dime, but still almost no thickness.
The weird thing is though, that I'm not sure it is material stuck to the sheet. It almost feels like material got pulled off the sheet. Is it possible I removed some coating when I pulled off the PETG print? When running my finger over and looking really closely it seems like the center is a bit higher but the outside is a bit lower. But my PETG is bright orange and this is more like translucent.
I'm afraid I already damaged my steel sheet after my first few prints. Are they that fragile? Could it have been defective? Is it impossible I removed some coating and there must be something else going on (like what??)? Is this something that just happens after enough prints and sheets get "worn out" and replaced, I just managed to do it quickly?
I flipped the sheet over and will only be printing PLA on the smooth sheet. I'll use the powder coated one for PETG going forward (I didn't have that first-layer calibrated when I printed the PETG and didn't know that's what I really should have used instead). Then I got to thinking, maybe I shouldn't be using this sheet anymore at all.
Got any information to help a newbie out?
Thanks.
Jason
RE: Smooth sheet coating damaged?
Doh! More searching turned up this post in the archive. Sounds like I likely have pulled some coating off.
https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-others-archive/coating-on-steel-sheet-coming-off/
RE: Smooth sheet coating damaged?
Hi Jason,
PETG tends to stick like crazy on the Smooth sheet,
Prusa used to recommend using Windex, as an adhesion reducing option on the smooth sheet. TPU also sticks like crazy...
If to get a model 'Stuck' again, try dribbling some IPA around the bottom of the model on the build plate, let it soak into the first layer / pei bond for a short while, and then try flexing the build plate again, to release the model.
sometimes models cause the PEI adhesive to lift slightly, often causing tiny bubbles under the surface. this will usually settle down after a short while and a couple of print heat cycles.
check the other side of the PEI out after a couple more prints, see what it looks like...
some people claim that the extured sheets can only be used with PETG and exotic filaments, saying that pla doesn't adhere to the textured sheets.
I find that if you keep them really clean, PLA sticks fine.
I use 70C on the heatbed for larger PLA models
Good luck with your prints,
you should be able to set up different profiles for your smooth and textured build plates
I currently have three build plate profiles on my mk3, one for the Prusa Textured build plate, and one each for the chinese textured build plate, and the chinese smooth build plate. in the last six months I have mainly used PLA on the textured build plate.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Smooth sheet coating damaged?
Thanks Joan. I plan to set up the profiles for each sheet, and will keep an eye on that smooth sheet after each use of the other side. If anything is too "stuck" I'll try some IPA on it too, making sure to go easy on the sheets now.
RE: Smooth sheet coating damaged?
I got impatient with one of my first ABS prints on the new machine, used a metal kitchen implement to pry it off, and pulled off a few chunks of the coating as well, thus ruining one side of the only sheet I had at the time.
I'm sure that had I waited for it to cool down to room temperature, it would have come off with flexing.
It was one of the rougher steps climbing the learning curve on the new machine. Fortunately that was probably the worst error I made, and most of my prints tend to be very nice and as expected.