If you’ve seen both a fused filament fabrication (FFF) printer and a wire welder, you may have noticed that they work on a similar basic principle. Feedstock is supplied in filament form — aka wire — and melted to deposit on the work piece in order to build up either welds in the case of the welder, or 3D objects in the case of the printer. Of course, there are a number of difficulties that prevent you from simply substituting metal wire for your thermoplastic filament. But, it turns out these difficulties can be overcome with some serious effort. [Dominik Meffert] has done exactly this with his wire 3D printer project.
Extruder cold end using a standard feeder roller
For his filament, [Dominik] chose standard welding wire, and has also experimented with stainless steel and flux-cored wires. Initially, he used a normal toothed gear as the mechanism in the stepper-driven cold end of his Bowden-tube extrusion mechanism, but found a standard wire feeder wheel from a welder worked better. This pinch-drive feeds the wire through a Bowden tube to the hot end.
In thermoplastic 3D printers, the material is melted in a chamber inside the hotend, then extruded through a nozzle to be deposited. Instead of trying to duplicate this arrangement for the metal wire, [Dominik] used a modified microwave oven transformer (MOT) to generate the low-voltage/high-amperage required to heat the wire restively. The heating is controlled through a phase-fired rectifier power controller that modulates the power on the input of the transformer. Conveniently, this controller is connected to the cooling fan output of the 3D printer board, allowing any standard slicer softwa ..