[bitsa]

I'm a complete CNC newbie, and am trying to get the 3040 machine working I ordered a couple of weeks ago. As first step, I wanted to create a spoil board, and take about 1mm off the top to get a perfectly flat surface. Unfortunately I'm running into the problem of the result being everything but flat, as the tool cuts deeper and deeper into the material the longer it cuts:



Could anyone help me figure out what could be causing this? In Mach3, the depth is constantly -1mm. One thought I had was that it could be due to the tool heating up and expanding (but I guess that's kind of unlikely, and it's much more likely that I made some newbie mistake).

Thanks for any hints!

[gfacer2]

Ok this is a total guess as I have no experience with steppers (as I assume this machine is). My wild guess is maybe wire noise is send extra steps to the Z when either the x or y moves. you could likely test this out fairly easily and my guess its whatever had to move out to do the next part of the pocket. Should be able to do a line made up of segments and see if the depth of the cut drops on each segment.

Anyhow - just a thought.

[gfacer]

I'd check the coupler from the motor to the ballscrew first....if its loose it would slip down. Missing or extra steps could be, but check mechanical first.

[bitsa]

Thanks! You were exactly right, and I'm clearly stupid. The coupler was slightly loose. With that fixed, it cuts flat. Thanks again!