Flexible circuit boards can be made using a 3d printer. While most filaments will not stick to copper, Ninjaflex will. Using circuitpat.stl a circuit pattern can be printed on a thin copper clad circuit board. It can then be etched in the standard way. A spacer bar is printed first which then lifts the printhead to the circuit board height. Detailed info on the process can be found at: http://www.instructables.com/id/Make-Flexible-Circuit-Boards-Using-A-3D-Printer/