Wouldn't it be nice, I wondered, if I could go straight from the computer file to cut-out parts? After all I have a CNC machine.
The problem is that a rotating cutter doesn't really work with soft materials like Depron. The cutting bit chews the Depron, lifts up the sheet, and tries to push it sideways especially when cutting thin parts. A laser seems the obvious choice, but high-power laser cutters in reasonable sizes are hugely expensive, fragile and dangerous. Low power lasers, while cheap, don't work with white Depron as the beam just gets reflected.
Recently however, I came across a fascinating thread on the Flitetest forum where an American aeromodeler had developed a way of cutting Depron based on a reciprocating needle - a piece of piano wire moved up and down like the needle of a sewing machine, punching a series of joined up tiny holes as it moves along. The concept is so simple that I had to have a go.
So here it is, made of parts I already had; a motor & speed controller, a spring from a clothes peg(!), piano wire and a bit of brass tube for the nozzle / guide.
