Making Metal Hot Using a DIY 1.4kW Induction Heater

An induction heater employs electromagnetic induction to heat metals via eddy currents generated by that metal as it passes through a coil. The coils are used in a myriad of industrial applications, including furnaces and some welders. Engineers and makers have also utilized the versatile tool for some DIY projects, and while there are small induction heaters on the market, some have taken to creating their own for a cheaper alternative.

Schematix is one of those who developed his own induction heater, which features a compact design about the size of a small shoebox and packs a pair of IRFP4668PBF MOSFETs, two 2.2uF ceramic 100V capacitors, and 10 WIMA MKP1J034706B00KB00 (470nF/630VAC) capacitors. It also features two FR307 fast diodes, two 47R/470R metal oxide resistors, and a pair of 12V (5w) Zener diodes. For the inductors, Schematix decided to wind his own, using 1.25mm enamel insulated copper wire with 30 to 32 winds around an iron powder toroid, which provides an inductance of around 100uH.

The DIY induction heater is capable of quickly heating ferrous metals but wasn't able to heat aluminum in any meaningful way. Schematix feels that he can probably improve its performance to melt non-ferrous metals via higher voltages, but doing so would produce a new set of challenges, mainly keeping the components cool enough. "Perhaps water-cooling would be a viable solution? In any case, it's certainly possible for this circuit to handle higher voltage than 48VDC if appropriate measures are implemented," states Schematix in his project blog.

It will be interesting to see if he can incorporate a water-cooled system within his design and if that alone will help achieve enough inductance to melt metal.