cam.openbuilds.com bug in generating tool path for arcs

I use QCAD and LibreCAD extensively myself. Explode all non polyline entities into Polylines, then save as DXF R14. See docs:software:file-errors [OpenBuilds Documentation]

We only support closed vectors. Having a missing side, we'll add one to make it a closed vector.

Give it proper closed polylines. This may entail converting objects to polylines / svg paths first and making sure its all joined up into continuous polylines/paths as needed

 

Checking our your actual file:

By-eye it should contain "2 paths" - the outside profile and the inside cut. But in the document tree we can see a lot of "paths" - because it hasn't been joined correctly - you have a tonne of short little segments but they aren't part of the "whole" as it should be. Highlighted a couple segments for you on the 3D view too, easy to see its seperate as you hover over them though.

Each of those segments should have all been joined together into one long PATH (or Polyline for DXF) - as its its not a cut friendly file and most CAMs would bork on it. Putting in clean data avoids forcing the CAM to try to figure out what you want.

In this case, I'd select the segments that form the outside, and Union them together first. Then seperately select the 4 straight segments and Union them to create a rectangular polyline/path. Thus ending up with just two polylines/paths as was you intention when you were designing it after all.

 

Drawn your holes as circle-polylines (easier on the eyes to see the right size of hole in the drawing, known what bit to use etc) then use the Drilling operation in CAM. It finds the center of the selected entity and does n proper drill job