The new fad in machine design seems to be torsion boxes. But, they're being made tediously by hand, or some of the fancier ones are using CNC routers to cut the ribs. Pretty good idea, as it reduces the mass (and momentum) while providing an extremely stiff final product.
But, they can be hard to build well. So, let's approach this from a different direction. I don't want to tediously hand cut all those ribs...what can I do?
A torsion box, by definition, is a construct comprised of a honeycomb of "space filling" ribs which hold skins in position while resisting compression. The skins operate primarily in tension.
Following this through to its logical end, we need something which acts well in compression, as the core. Styrofoam! It's easily available, cheap, and a snap to cut.
Skins -- thin plywood would work -- heck, paper would probably work, but I'd prefer something with more integrity for the outside of a CNC machine. Formica might be a good choice, as it's very strong, very tough, and designed to attach with contact adhesive.
Extremely strong structures are built using fiberglass over foam construction, and similarly strong structures with concrete, wood, and other coatings -- all over foam cores.
Has anyone built a router using this type of construction? It seems like it'd be a natural for homebuilders who want something strong and cheap.
Comments?
-- Chuck Knight