How to make a form for Sheetmetal

This is an overview of how I used a Shopbot CNC router at TechShop San Francisco to make an MDF form for making a hand-hammered aluminum bowl.  I am by no means an expert in sheetmetal forming, but this technique has worked pretty well for me so far, and I'm looking forward to experimenting with new shapes and curves in the future.

Step 1: Model your bowl

I modeled my bowl in Autodesk Inventor, which was an extremely simple process.  I made a rectangular extrusion that was 24" square, then projected a plane through its center.  I sketched a curve on that plane, then returned to 3D modeling mode and rotated that curve 360 degrees to make a negative bowl shape in the top of my extrusion.  I generated my toolpaths in Cut3D, where I was careful to set my Z-zero at the top of my material.

Comments

[PS118]

It strikes me that this might be a good way to make a parabolic reflector for:
* Wifi or RF dish
* Solar reflector for green energy or simple pyro mayhem
* Directional audio mic
* Maybe even a mirror for a Dobsonian telescope. How cool would that be!