At last after years of winding tesla coil secondaries by hand I decided to build a more automated winder. Ive not gone down this route before as the coils that I use for my electronic tesla coils are wound with thin wire, usually around 0.125mm.
Because of the need for really fine wire winding the build needs to be sturdy. The build is made from 6mm Acrylic from and old sign. held together with M5 bolts angle brackets and studding. The stepper motors for the lead screw and to rotate the coil former are bolted to this.
A single shaft parallel to the lead screw stops the trolley from rotating with the lead screw.
The spool is held in a jig that is mounted on top of the winder. The wire passes from this spool to the other end of the winder and then back to the trolley pulley. This long path ensures that the wire feeding into the pulley is always at the same angle to the trolley and pulley and therefore should always have the same tension.
The steppers are driven with two A4988 bipolar stepper motor driver boards. These are microstepping drivers capable of 16 steps per step and with the 400 steps per turn resolution from the type 17 steppers and the 4mm per turn lead screw, this gives me a resolution of 0.001mm per step. Good enough for even the smallest diameter wire.
The control software was written in C and allows the coil former to be spun at a range of speeds and the lead screw to be turned at any division of the former rotation speed.
The Coil former is held in position by a pair of stepped cones. Each of the steps suits a common pipe inner radius, so just by clamping the former between the two automatically centered the former to the shaft.