Before I print functional parts on the new and nice Moai 200, I readjusted the mechanics and ran the advance moai calibration. After that, I did some measurements of lateral laser accuracy. For this I screwed the build plate arm from the Z axis and put a CCD camera on top of the moai:
The calibration sheet lying on the platform was illuminated from below by the laser. With a corresponding long exposure (up to 10 seconds), the movement of the laser was recorded in an image.
Well you can see the typical distortion in the Y direction. In the corners, the Y-deviation is maximum (up to 4 mm):
A grid gives a good overview of the entire print area:
Here is a good comparison between laser (blue) and target grid (red):
Unfortunately, the XY calibration in Asura 2.2.2 is currently unable to correct the distortion in the corners.
Since the errors are not symmetrical, a bilinear correction in the individual sectors (10x10 mm) and a transformation from the laser coordinates to the nominal grid will be able to correct the distortion.
Initial programming attempts confirm the approach. For this I have adapted the path coordinates in G-code in a post process to the actual laser history.
If I find time to program again, then come some pictures and readings … Until then, the parts are made on the CNC milling machine.