What causes faceted curves?

[neilferreri (Neil Ferreri Ω)]

@Hollywood83

Do you happen to know what the step resolution is on the S5pro stepper motors?

I don’t. Can you see the $$ grbl settings?

This thread may be of interest.

Acrylic wall finish tips?

You might try cutting a straight edge that is 1 degree off axis; if the marks are about 1.5mm apart then I would say it is a limit of the machine resolution of 0.025mm/step. (or, replace your belts with ball screws and see if the spacing changes proportional to the steps/mm change)