I've been printing PLA for years, never got into PETG or ABS. I'm trying to print these feet for my chair but they keep cracking when I install them.
The first time it happened, I realized that the chair the STL was made for, and my chair, are slightly different models. Or at least I assume as much because the diameter of the clip on the STL is 12.5 ish mm and my chairs poles are 14mm. So I scaled up the model until the diameter of the clip was just a fuzz under 14, just slightly snug.
(Edit: I looked it up, the chair this was made for has 13mm diameter poles, so my scaled version is flexing even less than this guy's was! Something has to be wrong.)
I printed a whole foot, and it broke. I printed some sample clips of varying sizes and settings, and most of them broke, though not all, and I don't see a pattern.
Printer is an ender 3, one of the upgraded models, don't remember which. It came with a glass bed and has the updated hot end shroud design as well as the vertical screen and quiet motor driver 🤷♂️
PETG is Kingroon black, cheap stuff yeah I know, this may be my problem. But I print cheap PLA almost exclusively and I've only been burned once by crappy filament. Problem is I don't have any reference for how PETG should react in this situation.
Settings are 245c hot end, 70c bed. Everything else is the default settings for prusament PETG in super slicer 2.4.
Nozzle is stock .4mm. Layer .2mm.
I've tried 2 perimeters, and 3. 25% infill, and 31% infill, both gyroid. I want this to stay lightweight.
The STL is angled so the layer lines on the clip are about a 45 degree.
The ambient temp in the room is 65-70, radiant heat so no drafts, and honestly the room is kept at 65, the printing slowly brings it up to 70.
I've read that lowering fan speeds at different times during the print can increase strength, but I've never messed with that stuff before, never had to.
The filament is brand new, though I suppose it could be moist from the factory. Humidity in this room is about 50%, filament is normally stored in a dry box.
Any suggestions? Is this normal? I know PLA would crack if I tried to flex it that far to clip it on, but the maker of the STL seems to think it's fine with PETG. Thanks in advance!
Howdy! I have never calibrated my printer, in years, usually it's close enough I don't notice any issue. So that's a possible cause, I'll have to look up how to do that.
In the meantime, I redesigned the foot so it's a friction fit onto the rubber foot already on the chair. This has solved my problem for now, and it's 3 times lighter!
Admittedly it looks a little goobery, not the smoothest print. I'll look into calibration.