A few months ago I retrofited an old foam cutter based on a MM2001 hardware.

This system works quite well, but the unipolar stepper motors are very weak and prevent any fast motion... which is "annoying" when the hot wire is at one end of the machine and you want to go to the opposite side...

So why not building a brand new controller with the following requirements :

  • able to drive a hot wire
  • equiped with 4 bipolar steppers
  • driven by standard polulu shields
  • and with an ESP32 MCU
  • FluidNC driven
  • able to "eat" gcode produced by any "foam cutter" software

Let's go it's an easy project which shouldn't cost more than 10$ (without motors) !

Electronics

Schematics

This schematics is extremly simple as it implements 4 times the basic way to use a polulu driver

Apart from the steppers, the only usefull part is the hotwire. It's a 1m long 0.3mm nichrome wire which is fine tuned powered by a PWM under 24V (same PSU for the steppers).

  • PWM is produced by a two stages mosfets setup
  • the big BUZ11 takes care of the power line
  • the small 2N7000 is powered at 5V and its gate is triggered bye GPIO32 of the ESP32
  • 5V supply is delivered by the USB cord plugged into the ESP32

Finally I have added  two home switches inputs (homeX and homeY) although they are useless for a foam cutter!

And exposed a few more pins of the ESP32 to be use (or not) for future projects!

PCB

I have designed a nice and compact PCB allowing to "shield" the drivers and the ESP32 modules.

The PCB was kindly sponsored by PCBWay and is as usual of excellent quality.

You can order it here: PCBWay shared project. It's cheap, delivered very fast and so professional looking!

STAY tuned, project in progress !