Motorised Solder Holder

thingiverse

This project came about as a way to: a) Speed up the process of tinning wires b) Reuse some old 3D printer parts that were gathering dust It seems to do a pretty good job of both of these tasks. I ran the print at 50% infil in PLA. seems sturdy enough. 1) Print the two parts linked below. 2) Remove all the machine screws from the stepper motor 3) Sandwich the motor between the two pieces of print, with the circuit board on the back. (Use the fiber washers to ensure nothing shorts against the screws.) 4) Screw the extruder into the front of the stepper motor. 5) Set the tension by selecting an appropriate spring, and add the rubber o ring to the idler. This stops it chewing up the solder as it feeds. 6) Build up the footswitch, a simple NO button in a project box. The lid is laser cut perspex, but you could just drill it out. I also used a cable gland to clamp and protect the cable. 7) Connect eveything up, hope it works! Electronics: This requires fairly minimal wiring. As the A4988 has all its control pins on one side, you can just solder it into the stripboard next to the arduino and the pins will be connected one to one. The reset, sleep and enable pins are then controlled in software. It goes between pin D2 and D9. Double check that this will work for your driver, I doubt all the breakout boards have the same pinout. The button is connected to pin 10 and 12 (11 is blocked by the screw hole). Pin 10 is written low in setup and 12 is set to INPUT_PULLUP, so they can wire straight to the JST connector. I also had to add a jump wire (the purple one) for the trace of pin 12 as I cracked it while drilling, but this could be avoided. A second JST connector is added for the motor outputs of the driver. The motor in (Vmot) and ground are wired from a DC jack (fed by the DC power supply) with a 4.7uF capacitor across them. They are then wired to ground and Vin on the arduino. The Arduino 5V is then run back to Vin on the A4988. Using the Arduinos inbuilt regulator like this eliminates the need for an external voltage reg. Remember to drill out all the traces on the stripboard under the Arduino and the driver to avoid a chaotic mess of shorts! I will try and write up a more in depth guide in future, but this is all I have time for at the moment. I hope someone finds it useful!