There’s an old joke about the physics student tasked with finding the height of a building using a barometer. She dropped the barometer from the roof and timed how long it took to hit the ground. Maybe that was a similar inspiration to [Moe_fpv_team’s] response to the challenge: use a 3D printer to create a PC board. The answer in that case? Print a CNC mill.
[Moe] had some leftover 3D printer parts. A $40 ER11 spindle gets control from the 3D printer software as a fan. The X, Y, and Z axis is pretty standard. The machine can’t mill metal, but it does handy on plywood and fiber board and should be sufficient to mill out a PCB from some copper clad board.
It would probably be possible to beef up the design by using rods larger than 8mm. Of course, you could just attach a spindle or even a rotary tool to a 3D printer, but the fact that the machine uses leadscrews on all axes should make it better at forcing its way through the material even if it is a little slower.