[raynr]

Hi All,

I am having problems with homing the Z axis on the above machine.

The problem started with the Z axis struggling to rapid Z+ but Z- was ok. Turned out to be worn brushes in the SEM Axis DC Motor. These have been replaced and the machine put back together. (All wiring is correct as photos were taken before removing any wiring).

Now the machine is back together, when homing the axes the X & Y home fine but the Z now tries to home in the minus direction? and never homes but just hits the limit stop. The axis stops but the "Pass over Z-refenence Mark" message remains on the screen?

We have checked the Bosch axis boards and all 4 lights on them light up when homing.
We have removed the lid from the encoder on the Z motor and LED is on on the pickup
We have tried changing the software limits but had no effect
We have also changed the counting direction for the Z axis in the parameters and that does reverse the Z motor but just hits the Z+ limit stop

Does anyone have any ideas as it is doing my nut in!!!

The machine worked ok previously until the Z+ rapid (anything over 500mm/min) error started happening.

[RMARCH]

I would try switching the Z axis drive board with one of the others and see if the problem stays on the Z

[hawkins1996]

sounds like a sticky limit switch.