Material: 1 sheet of 16 Gauge Bronze (0.0598″ thickness)
Design: Modeled in Rhino with Grasshopper
Production Process: Bronze sheet was profiled with Onsrud Single Flute 1/4″ Aluminum End Mill Bit, engraved with Whiteside 3/8″ 90 degree V-Groove Bit. Two cutting fluids were tested: denatured alcohol and Soysol.
I found that using Soysol as a cutting fluid makes for much smaller chips, quieter operation (i.e. lesser vibrations in both the stock and the tool, which means lesser friction and heat generated). It is also much less attention seeking than denatured alcohol, which requires you to stand beside Monsieur CNC and spritz alcohol every few seconds. I found that I could get away with a good 5 minutes of cutting before the Soysol dissipates.
The great thing about Soysol is that it seems to be a real ace at preventing chip-re-welding, which means you get a cleaner cut with lesser burrs!
The only downside about it is that you end up with greasy bronze chips all over the place. Keep the dust collection boot down as much as possible.
Notes for improvement: Chips getting trapped under the sheet metal meant that the metal was getting raised and warped and not lying flat on the surface. Perhaps adhering the sheet metal to a 1/8″ masonite board prior to cutting might be a better option.
Feeds and speeds:
Plunge: 15 ipm
Approach: 17 ipm
Engage: 19 ipm
Cut: 23 ipm
Retract & Depart: 800 ipm
Depth/Cut: 0.008″ per pass (very conservative, this could possibly be doubled .015″)
Details of Project:
Name: Justin Lin
Date: December 2012
Class: Advanced Metals, taught by Carol Kumata