Thursday, June 06, 2024
Piezo Positioning Aid?
I just stuck a standard piezo disc on the stage (with a 1M2 resistor across it) and prodded at it with the probe. I'm getting a 0.02V response when the probe hits it with a positional accuracy of within 40μm - astounding considering the roughness of the piezo element and the fact that it's held down with a tiny piece of blue tape.
So, might be worth taking a side-trip to get some form of Z-height automation going on. So far the best algorithm seems to be to lower the probe until values happen, then lift the probe until they stop happening. There is a zero point in between, which complicates things and stops me just using it as a Z contact, and I have no idea what happens with fine probes (but I suspect it won't work so well...).
I guess the next step is to make a probe arm that holds a piezo with a tip stuck onto it and see what the heck happens. If anyone has been here already, please pipe up.
There is remarkably little noise introduced by the movement of the stepper motors.
