Yeah, it does seem that the default of pressure_advance_smooth_time=0.040 is too high. It’s not immediately clear to me what the default should be though (eg, 0.025, 0.020, 0.015, 0.010).
It seems an acceptable value is dependent on acceleration - the higher the acceleration the lower the smooth time should be in order to get acceptable results.
Interestingly, at least according to the simulations, higher pressure_advance values have similar problems with high smooth times. It seems likely that even on a bowden printer, a PA calibration test is likely to over estimate pressure_advance, which would reduce the benefits from that additional smoothing.
That is interesting. Oddly, though, I haven’t observed that behavior in real-world calibration tests. I tune PA after input_shaper and I haven’t observed a breakdown at the corners that the graph would seem to indicate.
In contrast, in retrospect, I do see a kind of under-over-under extrude pattern at the corners that is similar to what the basic PA simulation would predict.
Cheers,
-Kevin