Calibration and tuning

Calibration of your 3d printer is sometimes even more important than building it, and being SCARA, Morgan is not very forgiving in this regard. You have to get it right in order to get something resembling the stl you fed to your favorite gcode slicer…

I don’t like working too hard though, and thus I spent even more time writing up a calibration routine that will make it child’s-play… Well, almost.

Here is the wheel I printed for a small tricycle. The orginal calbration routine zeroed the arm angles to a line drawn on the top platform. While it works well enough, it caused the wheel to be slightly oval. While this does not subtract from it use, it is not quite how it is supposed to be.

In order to fix that, I had to change the way the calibration is done in order to focus on the angle difference in stead of the actual angles. Psi is now calibrated to Theta.

I am going to make some special phantoms in order to make the calibration process a bit smoother. After playing a lot with the steps per angle, I found a way to calculate the steps. The steps combined with the scaling factors makes it possible to get a perfect circle.