7. Computer-Controlled Machining

This we we are making our own furniture with large format CNC machine.

Assignment

Group assignment:
- Complete your lab's safety training
- Test runout, alignment, fixturing, speeds, feeds, materials and toolpaths for your machine
- Document your work to the group work page and reflect on your individual page what you learned
Individual project
- Make (design+mill+assemble) something big

Group Assignment

Modeling the Bar Stool

For this week's furniture I want to design a high-legged bar stool. I first start making the model in FreeCAD.

First using the FreeCAD Sketcher to sketch out the multiple pieces of my design.

I set different parameters in the FreeCAD spreadsheet to make my design in the sketch automatcally adapt to the maching and material status we are going to use.

The parameters defined in the spreadsheet also constrain and connect different parts of the geometry together.

Also add the dog bone cutout at every joints, the size of which is also controlled by the spreadsheet.

Cutting

Then it's time for cutting, the large format machine we are using is Shopbot. The material we are using are 12mm thick plywood boards, and we are using a 6mm diameter end mill for cutting.

I exported the sketches as dxf and imported them to Vcarve to plan the tool path, adjust the tool's parameters as following.

Finally it's assembling, the long joints of the stool are a bit tight, but after some sanding and hammering they eventually locks in very well.