Tests for position and orientation errors of axes of a 2D rotary stage

2D rotary stages are used in much manufacturing equipment. Besides the inherent geometric errors in each axis, the position and orientation errors between the two axes are also important position-independent geometric errors. Considering that the existing methods for testing position and orientation are complex, a simple method is proposed. A laser diode is assembled on the end of the 2D rotary stage's transit axis, and a position sensitive device is used to test trajectories of laser spots when the transit axis rotates. Then, the standing axis rotates 180 degrees and the laser diode is assembled on the transit axis's other end. The same experiment is repeated, and the position and orientation errors of the two axes are separated by comparing the center positions of the two trajectories. The test results of the position and orientation errors were less than 4 μm and 1 arcsec, according to calibration. (paper)