I have made a USD 2,- handheld cutter head for the PWM controller desribed in my previous blog post. The handheld cutter is nice for trimming off edges and so on. The spring keeps the wire tensioned. The final version don't need a series dropping resistor as the PWM driver stage uses two FETs.
The controller has also has been tested on a vertical setup for cutting spacers to my KFM3 depron wings (below):
The cutter gives nice clean cuts for vertical cutting operations (below). Please note the fan that sucks gases out from the workpiece. This is very important because blue and red foam gives off fumes that are very toxic when they are melted.
The PWM controller outputs pulses and is configurable both in duty cycle and several other parameters (below).
Based on interest, I may make a kit available.
Comments
By the way with a feedback loop controlled PWM cutter it should be easier to find the sweet spot.
the Vibration would move the wire longitudinally, so the cut would not be enlarged. I think I have seen such.
If you feel that you struggle to cut thru the material, it might be that you run to little current with the voltage you have available from your voltage source.
One test could be to shorten the heated part of the wire (put the electrodes that connect to the wire as close as possible to the piece that should be cut). Alternatively you could go to a thicker wire (less resistance). The best would be to try to increase the voltage with the setup you have. In case you have a PWM source, making the on time higher, would do the trick (provided the on time is not maxed out).
You might should measure both current and voltage drop on wire, and try to stabilize the wire temp.
- to be honest - I don't know ow to stabilize the wire - I use adjustable voltage power supply with current cut. Seems ok-ish - I still have trouble on EPP.
0-3.3 V output :) You could know the current & voltage on the wire. Set of an alarm if peak amps are to high.
For a short wire you need to use less voltage to limit max amps. I think I will order some parts soon. I could use one of these things. look here