Yet Another Filament Joiner

thingiverse

The heart of this filament joiner is an aluminum heater block that houses a traditional extruder heater element and thermistor, which work in tandem similar to an extruder. As such, it's connected to the 3D printer, allowing you to regulate temperature via the printer interface. On my printer, I've mounted a quadruple switch between the two thermistor cables and the two heater cables to seamlessly select between the joiner and the extruder. An additional LED, running parallel to the heater, indicates whether it's turned on or not. The heater block consists of two halves that are screwed together. A 3 mm hole is used to position my 3 mm filament, with 1.75 mm also being an option. Two 40 mm fans continuously cool the filament sticking out of the heater block, keeping it in check. The two pieces are held together by two clothes pins, making sure the filament is free from tension. If you don't cool it properly, it might melt and deform outside the heater. Here's how to use this joiner: Cut two pieces of filament at a 70 degree angle using a filament cutter, razor blade, and hammer. Remove the top half of the heater block. Position the two pieces of filament under the right angle against each other. Mount the top half of the heater block by fastening the screw and switch on the heater. Wait until the desired temperature is reached and then switch it off. Now wait for the whole thing to cool down to below the glass transition point of your filament, and open the heater block. This joiner creates welds that don't have a larger diameter than the hole in the heater block, thus avoiding filament jams due to a too large diameter. Print Settings: Printer: Custom Prusa i3 Rafts: No Supports: Doesn't Matter Resolution: 0.5 mm nozzle, 0.2 mm layer height Infill: 40% Post-Printing: To assemble everything together, use M3 screws and winged nuts. Some soldering skills are required. First drill a filament hole with your desired diameter in the aluminum block, then cut it in half at the intersection. All parts are mounted on a piece of 10 mm plywood covered with a 1 mm aluminum sheet. The springs come from standard clothes pins. For the rest, I think the pictures speak for themselves. If you have any questions or need further clarification, please use the comments section. I designed this joiner using FreeCAD.