Getting bad prints with new PETG
I bought a new roll of PETG and I'm getting bad prints, ie clumping. I've set the temperatures to the recommended range , 240 nozzle and 75 bed for the first layer.( It is Duramic PETG from Amazon) I recently did a cold pull. I've attached an image. Previously I was using the Prusament PETG configuration with this filament and it seemed better but still clumped occasionally and stopped the printer with a crash detection. I did just notice that the speed was set at 80 mm/s and manufacturer reccomens 30 to 70 mm/s. Could it be that? I'd appreciate any suggestions.
RE: Getting bad prints with new PETG
PETG is one of those filaments that can’t be printed fast. On my MK3S+ the Prusament PETG profile shows perimeters at 50 and external perimeters at 35. Infill at about 80. When you say the speed is set to 80.. that isn’t sufficient.. there are lots of speed settings in a profile. Also, for a variety of reasons, filament in vacuum sealed plastic can contain moisture. Only metal film bags are really moisture proof and the only company I’ve seen ship that way is Polymaker (any you have to then assume they’ve dried it properly in manufacturing). Plastic will pass some moisture. So you need to dry PETG. So lots of things you can try. Dry the PETG. If you are using a Prusa profile.. generally they are pretty conservative. Just check all the speeds.. reduce temp 5 to 10 to see what happens. Make sure you still get good layer adhesion. It might be only that your filament is damp..
RE:
I agree, PETG is often a nasty customer, but not all brands are the same. Prusament PETG is quite fussy in my opinion. Some of the colors I tried ( terracotta for instance ) are a PITA to print, specially large areas of infill.
Apart from drying the filament, be sure that the Z offset of the first layer is spot on and the printing plate perfectly clean (HOT water and dish soap). Besides, if you print PETG on a smooth plate, it's almost compulsory to apply a layer of glue/releasing agent ( 3Dlac, Laverneer, Magigoo and others). Otherwise you risk damaging the PEI sheet when you remove the print.
RE: Getting bad prints with new PETG
Thanks for the great advice. I was able to solve the clumping by moving the nuzzle up a bit. I was surprised by this because it has been printing fine where it was. I hadn't moved the printer or anything so didn't expect this.