Lots of people have problems printing with PETG. Me, too. But with a bit of tweaking, my PETG project case turned out great.

One really good use for a 3D printer is making small project cases. I need a case and lid to package my NodeMCU signal generator project. After doing the design, I realized this was going to be a big job. Even with 15% infill, my software estimated a printing time of around seven hours! I tend to run the printer on the slower side for better results. But seven hours?

When you do a lengthy 3D print, you always worry something might go wrong part way through and waste your effort. Fortunately, if the first few layers print well, that provides a good foundation for the rest of the job. For a long print, you also have to worry about corners lifting or warping, due to differential cooling across the part. You can reduce the risk of corner distortion by avoiding sharp corners. They have been rounded for this case.

But, which filament to use? I selected PETG filament. Warping seems worse with ABS. I usually reserve PLA for more intricate designs. But I have had challenges with PETG in the past. In particular, its extrusion can be somewhat stringy and sometimes comes out in blobs. These blobs harden and interfere with subsequent layers.

PETG Project Case – Some tweaking and it worked

After some experimenting, I made several changes to my printing configuration for PETG. They were both important. The first change was to increase temperatures to 230/225 degrees for extrusion, and 80/75 for the heated bed. Next, I lowered the nozzle distance to the print bed by 0.03 mm to get better squishing down of the bottom layer. Finally, I crossed my fingers.

Satisfied that the bottom layers were well printed, my Sunhokey Prusa i3 printed away for seven hours and ten minutes. I checked it once an hour, but otherwise hoped for the best. Success. This was the best PETG printing experience I ever had.