I purchased the 1000x1000 x carve in 2019, and recently purchased the upgrade kit for the z axis, motors, and stiffeners. Since then I’ve been noticing that, specifically on the detail pass, the z axis thinks it’s either higher or lower than it was zeroed at resulting in the detailed bit either floating over the work piece carving nothing but air, or digging in too deep ruining the carve. This doesn’t happen from the beginning of the detail pass, it seems to happen randomly half way though the detail pass. It’s as if the bit gets pushed up a little higher in the collet mid carve. Which is not the case because I’ve cleaned the collets, really tightened the bits, and it even happens with the standard x carve bits that come with the plastic stoppers on them, which I seat all the way up so it’s impossible for the bit to rise any high in the collet. The only thing I can think of is something is wrong with the z screw. Any ideas?
Check the set screws on the coupler at the top of the z axis lead screw, the coupler is only accessible from the back side. These set screws are not properly torqued from the factory and have been known to come loose on more than a few customers in the past few months…
BUT ALSO check the grbl settings and ensure they are set correctly at the default values…
I found that changing the carve setting for the detail pass for the plunge setting from a ramp plunge to a straight plunge solved the problem. Not sure why but it worked. I ran the same detail pass twice and the problem continued, I changed the plunge type to vertical, and it worked fine. Must be a software bug.