Setting up meshcam 4th axis machining?

Having some issues with setting up meshcam to cut a 3d STL file.

I think the problem is how the part is placed in meshcam so far as Z zero is concerned and possible how the machine (4 axis mill) is set to zero.

I've been setting up the mill with all axis zeroed to home position and after choosing a cutter I zero the Z axis so that the tip of the cutter (ball end mill) is right at the center of rotation of the A axis.

Getting some distortion on my parts sometimes.

Anybody have a step by step on how to set up a part in meshcam and then how to set up mill to carve correctly?

Thanks!

The setup sounds correct. How are you finding the center of rotation and how distorted are the parts?

-Rob

recalibrating the mill today. Will run a test in the next day and report back my findings.

Part is not carving properly. Looks like Z depth is too great. I have the z axis zeroed with the tip of the end mill at the exact center of rotation of the A axis.

Here's two pics of the finished carving.

I'm attaching the meshcam file. Just change the venus.zip to venus.mcf to open in meshcam. (CNCzone won't allow me to upload with .mcf extension)