The bed should be parallel to the build plate and Y axis. If it’s not, something was not installed correctly.
The Z axis should be perpendicular to the build plate on all 4 sides.
The Y axis should be perpendicular to the Z axis on all 4 sides.
The X axis should be perpendicular to the build plate on all 4 sides.
The material plate should be perpendicular to the X axis, although it’s hard to get a square in there to test.
If those things aren’t true, you likely have some debris in between the part and what ever it’s connected to. It’s pretty easy get some debris wedged in the odd crevice when machining. Once you find the area that isn’t square, you’ll likely see a gap when the two parts should be touching. Where ever the gap is largest is likely where the debris is. Just take it apart, clean it, reassemble, and retest.
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