Hi, Thought you guys might be interested in my experience of a Hermes nhi810 engraving machine.
When I first bought it it worked perfect. Then every now and then the Z axis
went crazy and dug into the work every now and then.
Tried levelling the vice - within 0.001". No matter what I did, it still did it.
Eventually the power supply packed in. The power supply was replaced with a more modern one and serviced by a an engineer. It still went crazy.
Then one day, for some reason, I stripped it down. The Y lateral bearing slides were gunged up with old hard grease. Never been touched in its life by anyone. Cleaned it up, regreased, For the last 6 months PERFECT engraving - after I found a plastic grommet, underneath, an allen screw that allowed you to take the slack out of the Y axis.
All this is NOT in the manual. With hindsight, I think by the extra load, made the steppers take more current, overheating the power supply and eventually packing in (and of course - going out of step)
Hope it comes in useful to someone