[Rhys Jones] has been working with the RepRap team to establish a method to print circuit boards. The machine very first prints the plastic substrate with channels for the metal to be deposited into. They adapted their pinch wheel feeder to work with solid core solder (flux produces a mess). The extruded solder’s specific warm isn’t hot sufficient to melt the plastic. They made a video (embedded below) of their test piece: an optical endstop. The team has likewise been experimenting with decoupling the feed system from the extruder.