Isaac Anderson's 3D-Printed Parametric Coil Winder Can Handle Windings of Almost Any Size

Maker Isaac Anderson has been building a Tesla coil, and rather than face the pain of winding coils by hand decided to automate the process — building a custom parametric coil-winding machine.

"If you have ever wound a transformer, electromagnet, or guitar pickup by hand, you know how frustrating it can be," Anderson explains. "I ran into this issue while trying to wind the secondary for my Tesla coil. Due to the size, counting the turns and rotating it to wind the turns were both difficult. Instead of building a specialized jig just for that project, I instead designed a parametric coil winding machine using easily obtainable parts capable of winding coils of all shapes and sizes."

The winder is built from a combination of 3D-printed and off-the-shelf parts, including aluminum extrusion for its frame. Designed in OnShape, with a custom PCB created in KiCad, the machine's winding head is based on those found in commercial machines — but in cost-reduced form: "Instead of expensive winding nozzles," Anderson explains, "I used two POM blocks with different groove sizes cut inside to lay the wire. While a belt-driven design would be simpler and cheaper, belts are less rigid and precise than lead screws."

The winder works by rotating its spindle while moving the winding head horizontally — both under the control of independent stepper motors. Every time the spindle has completed a rotation, the gantry moves a distance equal to the diameter of the wire to ensure that the next coil doesn't overlap the last one. If multi-layer coils are required, the winding head can reverse at the end of the bobbin to lay the next layer.

"The magnet wire first gets taken up off the spool into the pickup arm mounted on the gantry," Anderson explains. "This elevates the magnet wire away from the gantry and prevents it from tangling. This then enters an adjustable magnet wire straightener and tensioner before being picked up by the adjustable (in both length and angle) magnet wire laying arm, going through a cleaning pad, then through the POM guide onto the coil. In my setup, I used a specialized magnet wire tensioner though this is not required. It is meant to keep a constant tension on the magnet wire and absorb sudden changes in tension."

The full guide, including design and 3D print files, is available on Instructables; source code, written with the Arduino Nano R3 or compatibles in mind, is available on GitHub under the permissive MIT license.