[Jeff Durst]

Need some help diagnosing a jagged edge on cuts diagonal to the x and y axis. I am getting clean cuts parallel to each axis but when cutting at an angle I get chatter. I am not sure if this is a rigidity or a drive problem. The machine is home built with cncrouterparts rack and pinion and rollers on the x and y axis and profile rails and ball screw on z. I am driving everything with a Gecho 540 and Mach 3. Everything seems tight. The sample pics were cut with a new 1 flute downcut spiral, 180 IPM, 20,000 RPM, climb rough pass with conventional cleanup pass. Any thoughts would be appreciated. Long time reader first time poster

[the_canuck]

Hmm....

Looks familiar. I believe we are fighting a similar issue.

http://www.cnczone.com/forums/diy-cn...-software.html

[ger21]

What do the other edges look like?

I've read about similar issues on diagonal cuts on rack and pinion machines with low resolution.

Have you tried doing conventional rough cuts? From my experience, climb cutting can leave a very bad edge, which may not be entirely removed by the finish passes. Also, single flute bits do not give a very good finish in MDF. I'd use a 2 flute with conventional cutting, and I think you'll see better results.

Also, make sure the rack and pinion is running properly, with the pinion tightly into the rack.

[FandZ]

If I had to guess I would say check your connection between your motors and gear. Probably one of your pinions has just a little bit of play. I've had a similar issue on my dual drive axis.It had just a little bit of play in a coupler. It wasn't enough to to slip and pull the gantry completely out of square where one of the motors would stall but just a little bit of back lash on one side of the machine.

[Jeff Durst]

quick follow up on my jagged edge issue. The issue was belt tension in the rack and pinion. I ended up making a screw jig to move the motor and tension the belt. I had been using hand force to tighten this in the past. I see their new pro series incorporates a way to tension the belt. Thanks for the responses and this site for its great info