I don't think it is a loose camera lens. We are actually off on the position of the Z-rod. It's not just the camera position that is off. We really can't change nozzles because the z-rod misses the hole in the nozzle changer.
We have repeatedly cleaned the glass scale, and we can see no problem with it. I'm not sure what we could do if the encoder that reads the scale is bad. The optical encoder appears to be an incremental encoder. This means it can keep track of where the head is based on how far it moves, but it still needs to know where "zero" is when the machine is powered up or reset. The machine will power up, move the head around (I guess to find the "home" or "origin" point), and will sometimes be in calibration, and sometimes not. If it is in calibration it will sometimes stay good for hours. Then suddenly the X position jumps off by 30-40 mils. Power cycling or resetting does not seem to always fix the out-of-calibration situation. Sometimes it gets out of calibration and no amount of power cycling and/or resetting will make it right so I give up. The next day it might (or might not) power up back in calibration.
So my question is still- How does a machine with an incremental optical encoder find the absolute zero reference point at power up?
reply »