For position and linearity, you really need the calibration constants from the factory. Chinese producers of galvos are very reluctant to publish the numbers for position sensing's " Input volts per degree".. For linearity, you need a really, really, good single axis test jig and oscilloscope or data acquisition system. I have seen the adjustment procedure only for Cambridge products, and I've been at this a long, long time. Linearity control is highly dependent on the position sensor design, and that varies widely. As Buffo says, Linearity is the last thing I'd ever touch.
Steve
Qui habet Christos, habet Vitam!
I should have rented the space under my name for advertising.
When I still could have...