Uneven carving depth problems

[rpstealth]

Lately I have been having problems with the consistency of carving depth when using my machine. For example, for a carve programmed to be at 1/4 inch, it would start as such, but as the job progressed the the carve would get deeper and deeper and finally end up to be 1/2 inch deep. The end product would almost look like a staircase.

I have tried several things suggested on other posts with no success. I have changed the QC, lubricated, cleaned, re-calibrated, bought a new carving bit, and leveled the machine. None seemed to have affected the performance.

I am thinking that it might have to do with the sensor that tracks the height level of the z-truck. Somehow during the carving process it loses track of the inital thickness of the board.

I have attached some photos of the problems I have been encountering. Any help would be greatly appreciated.

Thank you.

17775

17776

17777

[Ron Baird]

Take the black plastic cover off the back of the Z- motor and blow the dust out of the sensor gently as to not damage the clear plastic disk. When you replace the cover put a tiny bead of silicone cocking around the edge of the cover to seal it. This will probably solve your problem.
Ron

[rpstealth]

Thanks Ron for the suggestion. I cleaned out the sensor as you mentioned I still have the carving depth issues. Anything else I can look at or try?

[Amonaug]

Give LHR a call. It could be a faulty Z encoder. Also make sure there are no chips or anything stuck in the teeth of the Z-belt/gears.