Looking good. Here’s that digital potentiometer video I was talking about.
https://www.youtube.com/watch?v=uezoQ5fkixY

Theres some people in the comments saying you could digitise the buck converter without any desoldering or fancy extra chip. May be worth looking into?

You don’t have to remove the original potentiometer of these buck converters. You just need to “inject” some extra voltage to the shorted pins (pin 2 and 3) of the onboard potentiometer through a resistor and by this you can trick the buck controller chip and control it perfectly. I did this already quite some time ago using a MCP4725 12-bit DAC and an SZBK07 buck converter. This DAC has higher resolution than those digital potmeters, so you can control the voltage on a really fine scale.

We recently used this machine to cut shapes out of XPS foam, AKA ‘blue board’. The working piece was approx 1000mm on the wire axis.

These settings seemed to work the best for smoothness of cut:

Parameter Value Material XPS Foam Material Size 1000mm on wire axis Feed Rate 350mm / min (F350 in G code) Wire Power 55V / 3A Wire Diameter 0.4mm Kerf Size 1.0mm

Adjusting drawings for kerf is critical to getting the correct piece size. There did not seem to be a kerf feature in the hotwire controller or vector linker software so we added this manually to a solidworks drawing using the ‘offset entities’ sketch tool.