I’m printing some change gears to check the fitment of the gear train on a banjo. I have been fighting with this particular brand of PETG trying to get a clean and accurate print since last week.
Notice on the 2 20T gears the poor bores and under extruded 5 layer top surface. They were printed with a hardened .40mm nozzle on a Bambu A1 Mini. They do NOT fit the spindles on the banjo at all.
Now look at the larger 80T gear. Clean teeth and bore with proper flow rate on the top surface. (Yes the infill is showing a bit due to the mere 3 top and bottom layers I printed it with to save on filament). This gear fits as it should right off the plate.
Same exact filament, same printer, same exact slicer setting. Just a hardened .60mm nozzle swapped for the hardened .40mm nozzle. And dried to 14%Rh for days and I printed directly for the dryer.
Soooo much time and filament wasted calibrating and recalibrating for that .40mm nozzle and it still failed. All I needed was the .60mm nozzle. But, still a new and interesting phenomenon to learn from for me.
Do you think the dryer or the nozzle helped more?
Dryer didn’t do squat to make a difference. The filament was at a steady 14Rh for several days for both nozzles. The only change that made a difference that made a difference was the nozzle swap.
No kidding! Thanks. I’m going to get a 6mm.
Maybe something to do with your max volumetric flow rate? Could cap that lower and see if anything changes with the 0.4mm
Been there done that. Didn’t work. It did print the calibration print just fine. It just sucks when I try and print these gears.
I second this. I’ve had far more issues printing small parts than large due to printing too fast. I like to use minimum layer time, but max flow rate works too.
Have you considered just using gear molds? Or getting some machined if they’re super custom and you’ll be making several of the same gear and replacing them over time.
I need to know if the gear train will fit on the banjo of the lathe first. I might run the plastic just to see how long PETG might last. If I want metal change gears, I will either spring for the 100+ dollars needed to buy the proper gears. Or I will spend $60 for the proper cutter and cut my own gears. But I need to be sure they will fit first.
