So, today I had to improvise a tool to make 45 cuts at a time (for the sake of efficency) in 30 foam bars, so they could be divided and glued to cardboard to make board carriers for 3600 boards.
Easy, just drill some neat looking holes, put some rivets in there to hook the cutting wire, and there you go.
The thing is that I didn’t had nichrome wire at hand, at least NOT a spool of it. Some thinking head dared to suggest using copper…yeah, engineer pls, leave the improvisation to the practicality experts…
Of course, copper wire might have worked as a last resort, ultra emergency, that-or-I-will-cut-my-veins solution, however, working at an electronics engineering, with a somewhat decent warehouse, you DO have nichrome wire around.
Where?, did you say?
Wirewound ceramic resistors!
Just crush a big one (10+ wats) with a big vice, and you’ll get about a meter of whire. Magic! I used three(3) 47R. power resistors.
Also, don’t forget to use a low ohmic value, otherwise you’ll get too thin wire, and it will break easily.
Nylon spacers where used to have almost exactly 10mm heigt while hammering them down, so I didn’t have to take measurements while inserting them.
Also, should you use a similar lenght as mine, be warned, this used 240VDC at 1,2Amps. (288Wats!!) Interestingly, the width of the cut is somewhat controlable through wire temperature, so you can make life easier on the lateral connectors on the board sides, when sliding it and out of it.
And the cutter? It worked like a charm! Even with a lot of slack of all that wire lenght, the cuts where decent enough as to not need to put some springs in there to mantain tension.
And the leds are protected all the way to the customer.