Carbide Labs is coming out with a new low-cost tool setter for tool height measurement in CNC machines. Part of the tool setter is an internal switching mechanism made using a custom PCB machined from 1oz copper clad laminate board.
In order to engrave and route the board we needed to create a custom fixture plate to hold the PCB flat on the worktable. We made the plate by starting with 6061 aluminum and fly-cutting it flat. We then drilled the surface and tapped for M5 bolts. The part was laid out so that the overall fixture was clamped to the work surface via bolts to the worktable T-slots. Then laminate was bolted in two ways to the fixture. The first set of bolts were placed in the center of the initial engraving for consistent cutter interaction. These bolts have to be removed during the routing operation, however, as they will cause a crash if they interfere with the milling tool. A second set of bolts was placed to hold down the overall sheet during the routing. The last feature we included was two engraved lines for guides during initial alignment, copper scribing, and fixture bolting.
We’re milling these on a Sherline mill with a tiny worktable, but we can still crank out three sets of contacts per run. There will be two operations, one 1/8in corner mill for engraving and one 1/8in flat 2 flute endmill for routing.