Tips on 3D surfacing ABS-like plastic

Hey,

Fairly new to the whole machining world but I can run my machine no problem. I come from a 3D printing background. Some time ago, I decided to mix 3D printing to CNC machining in order to create complex parts with nice finishes. The complex part side is OK, the nice finishes side is still in the progress. Looking to get tips on CAM programming and right tools

So the plastic I am machining is PETG ( Glycol-Modified Polyethylene Terephthalate (PETG, PET-G) :: MakeItFrom.com ) It's similar to ABS on many sides and it can definitely be machined to nice finishes. I'm able to get really great walls on 2D contours. Where i'm struggling is on 3D surfacing. I'm using F360 and a combination of parallel and scallop tool paths with really small stepovers. Running harvey's 1/4 ball end mill with recommended settings which is about 0.0065 IPT and 1200SFM. There's no roughing passes because the part is 3d printed with a small stock to leave of 1mm. Oh, and i'm using a CNC kit similar to CRP. Check the machine and there's almost no backlash and try little deflection... Anyway there's not much tool pressure cutting this.

Any advices would be appreciated. I can post settings when i get to my work computer.

The surface defects appear to me as issues with machine performance. Backlash, deflection, stiction, spindle float are likely mechanical causes. Poor motion control from hobby grade software and hardware could also cause these type defects.

This forum is not targeted at DIY router type machines. You will most likely get better advice at a hobby machining type forum.