I’m new to Bambu and don’t know what to expect in terms of dimensional accuracy. After printing several square/rectangular parts, I calculated my shrinkage value to be 99.4% for Polymaker ABS, red color. The ABS was dried before testing and has been sitting in the AMS2 at 7% humidity.
The round section of my part is consistently too small but the square portion is dimensionally correct. How do I make the round section bigger without affecting the square section?
I’ve tried:
Changing the shrink factor (makes the square too big)
Auto circle contour hole compensation (not much difference)
X-Y contour compensation (makes the square too big)
Slower print speed (made problem worse)
Bigger in CAD model (best solution but harder to manage)
Yes it’s gcode issue. Basically arc fitting is trying to make up a circle while it’s actually a lot of connected points. And then it has to apply shrinkage compensation (if you have done any). Lots of different things altogether.
I’ve done a lot of analysis on the gcode generated by Bambu Studio. The arc fitting function is inconsistent. Details are in the Bambu Studio thread I posted above.
Which did you use for a model file type, a STEP, or STL? I assume STL due to the number of faces in the screenshot. If correct, have you tried using a STEP file, or any file type that support an arc?
I just imported as STEP and used 0.01 for the angle deflection. This created lots of triangles. The Arc fit generated two arcs and short linear section.
The two arcs were still 0.69% smaller than a square in terms of gcode steps/mm.
