For one of our customers we regularly mill transport/support foams for their parts out of styrofoam. We get the 3d files of the transport foam from the customer. They generate these files by taking a negative from the original part. These are usually mesh/stl files.
To keep things cost effective we want to use a milling tool which is large enough in diameter (between 20-30mm).
It is not a problem that most of the detail gets lost by using such a big tool. However, it is a problem when the model has a too narrow groove of gutter or other feature.
We rather have it so the tool takes away to much material instead of leaving rest material. What would be the best option to adjust the 3d model so our tool can get around the part taking material away everywhere?
Should we be looking at Rhino for this? Maybe look into using Grashopper? Or maybe some different software is most suitable? There is no option for this in our CAD software.
I use RhinoCam software to program our CNC routers and if I had to force a large cutter though a narrow gap in a soft material like foam I would use an engrave operation instead of remodeling the side walls. This way the tool path will follow a central drive line irrespective of the side walls.
Basically the part should remain the same, except for where the clearance is smaller than the tool diameter. On these places we would like the part to be offset to allow the tool through
I extracted the edge where the mill bit is running along and offset this curve by 10 mm inwards with Clipper. This polyline is divided into roughly 5 mm long segments to be used as a toolpath.
Mesh boolean union and subtraction of the bit along the toolpath failed so I’m subtracting the bit as a polysurface along the toolpath from a slightly larger bounding box than your mesh. The resulting polysurface is converted to a mesh after the boolean subtraction and then remeshed for a boolean intersection with the original mesh.
The definition below runs fine in Rhino 7. I’m not sure if this is going to work in Rhino 6 since the mesh tools have been updated in the meantime.
All inputs, some intermediate results and a final mesh are internalisedd in the definition below. Time consuming components are disabled. The loop in the python script took almost three minutes to complete.
This looks very impressive and promising. Looks like you put a lot of effort into this.
It is my first time I am really looking into using grasshopper, I never needed it before, I’ve been looking at some tutorials to get started with Grashopper because I don’t want to let your efforts go to waste.
I have a new stl model open in Rhino and the grasshopper Recipe in a different window. Only I don’t understand how I can input this new mesh into the project and to get a result? Looks like I am just missing something stupid to get started…
