A Custom designed soldering iron for ME318


A better soldering iron

After a lot of searching for ideas, and soul searching on my part, I settled on a soldering iron, as a personal and meaningful project for ME318: Computer Aided Product Creation. After a lot of design iterations, I settled on a round dial design with an OLED readout in the center. I based my design on the Weller WES-51, and did some hardware hacking to make allow me to control the iron from my own microcontroller and do the interaction design myself.

Initial Machining

The face of the soldering iron was machined from acrylic on a HAAS office mill, so that when finished, it would have a really clean glossy black finish. I used a custom fixture plate, and prepared my stock using a laser cutter to avoid having to spend time machining the stock to size. Each piece of stock is properly constrained using a pinhole and a slot to allow me to do part flips while retaining accurate datums.

Detail Machining

The primary input for the soldering iron is large, custom made encoder cut from a piece of aluminum with a large number of teeth that provided a nice fine resolution. The encoder was built from a pair of IR sensors mounted ninety degrees out of phase in the face of the iron, detecting the reflective difference between black acrylic and aluminum. The aluminum provides a good brushed contrast to the polished black acrylic, and a nice distinct touchpoint.

Face Assembly

With the parts for the face cut, I added in the electronics and LEDs to make a good display, and then added in diffuse acrylic pressed into the face to prevent there from being hotspots and blend the LEDs together convincingly. Stainless steel fasteners hold the entire assembly together, and then the entire assembly is fixed to the back portion holding the transformer. The microcontroller that interfaces the input and display with the stock soldering iron also sits just behind the face.

Iron Holder

With the body and face of the iron done, I moved on to making a custom iron holder that matched the lines and the aesthetic of the main iron. All the parts are pressed together, which works well due to the low required force of the holder. The barrel of the iron doesn't get very hot, so the frame of the holder works just fine made out of aluminum.


The outcome of my project was a soldering iron that has a more intuitive interface, more information and feedback about the state of the iron and a cleaner look sitting on my desk. I learned a lot about the nuances of machining in my first exposure to CNC, and about my own design process. I'd like to thank Craig Milroy for never letting any of my bad ideas slide as maybe even okay, and forcing me to broaden my thinking.