I am running a GRBL controller with the infamous TB6560 driver with Nema 23 motors. Lately my Z axis will not always return to the zero position. To reproduce the issue I have a gcode file to simply moves the Z axis up and down 3 mm ten times and then back to zero. 25 % of the time it returns to 0, but 75 % of the time the return point is lower than zero. I have tried the following without success :
- changed the micro-stepping to full step, 1/2 step and 1/4 step
- reduced the feed rate - GRBL : $112 to 400 mm/s
- reduced acceleration - GRBL : $122 to 10 mm/s^2
- used shielded wiring to connect the Arduino to the TB6560
- lowed the voltage to 22 volts
- replaced with another TB6560 driver
- checked the couplers and mechanics of the Z-axis - it runs smoothly
A replacement driver: DM556 is on it's way but wanted to see if there was any other experiments I could run. My X and Y axis have already been upgrades to the DM556 but they did not have this issue.