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The machine should not be moved or even slightly touched while the optics calibration is in progress.
Verify the optic calibration target is secured with clay on the glass en and does not slide out of position while the optics calibration is in progress.
Make sure the machine is sitting on a stable stand and that the stand does not move or vibrate when the machine moves.
Verify that the stage glass is locked on the stage and does not move independently from the stage movement.
Verify that the camera is not loose, as well as the lens assembly.
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Focus on the center of the optics calibration target.
Using one finger slightly push the Z-axis from in the X and Y direction at the ringlight.
Verify if the position of the camera returns to the center of the optics calibration target after the push.
Repeat steps 1 and 2 pushing the Z-axis from the, Z shroud, zoom assembly, and the X and Y stages.
If the position of the camera does not return to the center of the optics calibration target, that means something is loose in that portion of the machine and needs to be tightened.