Foam Cutter Circuit Board

[TorontoBuilder]

https://oshpark.com/shared_projects/PJVty9F0

Circuit board for variable output foam cutter using either a "short" 24" or "long" 48" Nichrome Wire. (wire may be shorter say 12" or so, but too short may end up too hot yielding poor cut quality)

Uses a SPST switch and a 5K Pot to adjust the power output. The SPST switch bypasses the 5 Ohm resistance when using the longer 48" length of Nichrome wire.

When using the shorter 24" wire the switch directs the current through the 5 Ohm resistance to make up for the drop in resistance of the shorter Nichrome Wire.


Minimum BOM:
Transformer, 25.2 VAC, 2 Amps
TRIAC 400V 6A TO220
Heat Sink
5K linear potentiometer
Two 10 ohm resistors, 10 watt, (in parallel they make 5 ohm, 20 watt resistance)
470 ohm, 1 watt resistor
0.22uF Capacitor
SPST Switches, 2 required (1 main power on, other is long/short nichrome wire switch)
1A fuse & fuse holder
2 Banana Plugs terminals or similar
Nichrome Wire
Enclosure

Optional: power on indicator lamp

NOTE: to download file without corrupting it "right click" the file name, then select "save as" to save the file, otherwise the file extension will be altered to .txt instead of the required .brd extension

View attachment foam-cutter-test.brd

View attachment foam-cutter-test.sch

 

[giel]

Use a atx 200watt power supply 12v output yellow and black, use the wire from a hairdryer about 60 cm and power it up, cuts foam up to 50 cm thick, and if its going to hot make the wire longer or use the 5v output black and red wire .. built my hovercraft with it..
Ohh yeah hang a spring between the wire and the connection point to keep it tight


https://photos.app.goo.gl/8UobR5FDsqT2qqjy9