Hi all,

I have a recurring problem with my Z axis that I am beginning to think may be as a result of insufficient holding torque from the motor.

The problem is that during the cut the Z axis drops and continues to drop throughout the cut to the extent of approx 0.75mm after 15 minutes and as a result it cuts into the table top.

The Z axis is the only axis (on a 3 axis machine) that suffers the effects of gravity and to be honest the whole Z axis set-up including the router itself is quite heavy. I've checked the shaft/motor coupling for any slipping and it's solid.

I can only put it down to the weight transferring too much torque to the motor via the ballscrew.

I was wondering if anyone has experienced a similar problem or could help me calculate how much torque my ball screw is applying to the motor.

The holding torque for the motor is 1Nm