Hotwire Foam Cutter









I recently finished my hotwire foam cutter and am happy with the way it turned out. I plan on using this to simplify the production of patterns for lost foam casting (see the foundry pages for more information on this technique). I lucked out and had most of the bits and pieces that I needed for this project leftover from some other projects.

The power supply I used is a little more involved than what is required but it works well and I had the pieces. I used a PWM (Pulse Width Modulator) to control the heat to the wire. This is a simple electronic control that essentially turns the power to the wire on and off very fast and you can control this rate. I used a 12.6 volt, 3 amp transformer to provide the power, a bridge rectifier to convert the AC power to DC power, and a large capacitor to filter the DC power. The filtered power was then fed to the PWM pcb. The output from the pcb goes to the cutting wire. There is a rheostat which controls the wire heat and an on off switch (with an led power indicator) located in the little project box attached to the lower front of the cutter, it is visible in the picture below.

hotwire foam cutter

I don't know if there will be any requirement for it but I also decided to make the unit so the cutting wire could be tiled to make angled cuts. It will tilt up to 45º either side of vertical and the bar that clamps it in place is engraved so you can set a given angle, this can also be seen in the picture below. I used my CNC Taig mill to do the engraving.

hotwire foam cutter angle adjustment

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