Core XY mystery (4 replies)

I recently built a corexy. It is running pretty well. In some of my final calibration, I noticed one area that is off.

Say you print a tall square object. Looking from the front of the bed, If the object is 150mm tall, If I check the left side of the object to the bottom of the object I find that the object is not a square 90 degree angle, it is slightly less. Meaning that the upper layers drift very slightly to the right. Over 150mm object, I measured the drift at about 1.5mm.

So the first thing I checked was the bed, to see if it was moving up and down or at a slight diagonal. To the best of my measuring abilities, it is moving squarely down, and not drifting to the side.

Here is a writeup on my printer;
n9jcv Hypercube

I then checked the frame by measuring the rectangles/squares diagonally and they all appear to be exact, at least to the best of my measuring

I can not think of what else would cause this. Any ideas?

Thanks