Cutting a curved shape from a block of aluminum

[eljainc]

Hello,

I need help with generating a part to an STL file. I had a colleague of mine generate it but it was not curved, but instead angled. We are using DeskCNC (Carkin) to run our CNC XYZ router table, but that's a whole another issue. It will accept DXF or STL files, but since this is a 3D part, I was told that STL might be a bit better.

This is generally what we want to machine:

However, the part we are trying to machine is a block that is 4" x 4" x 1/2" thick with a cylindrical shape cut out of it so it appears similar to this:




Again, it is not 8" x 2", it is 4" x 4". The radius required is 5 17/32".


So basically it's a block minus the cylindrical portion removed. I have tried several different CAD programs including FreeCAD, but could not getit to work. Call me a CAD dummy.

I am attaching what I came up with for the STL file and resulting G-code (NC code).
However, when I run this on our setup, the axes stall through DeskCNC. Maybe the
rapid moves are stalling the motors? We have been able to cut simple parts with the
same config, but then again this is a different type of G-Code file.

Any hints or help are very appreciated.

Thanks
Mike