I've tried to machine a diffuser for R25. Miscalculated stock size and ended up with no support outside frame at all. But actual problem appeared when my mill stopped to make moves on Z axis. Looks like saddle nut got damaged, because I failed to adjust backlash lock. Didn't realize it wasn't setup at all, when milling column arrived new. Waiting on for new saddle nut to arrive from Sherline.
Here is the picture of machining process before part was ruined.
Correct roughing toolpath was generated using PyCAM. It was not optimized and lot of movements over Z axis were required. But job could have been done if mill hasn't failed.
For my second attempt I'm going to use bigger stock and generate more optimized toolpaths.