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Hot-wire foam cutting answers

A searchable, curated library of answers on foam cutting, machine setup, G-code, FluidNC/GRBL and the free cncfoam.com tool. Most questions are already answered below — search or browse by topic.

Category: All General ✨ AI helper Building / DIY Hardware Electronics G-code Cutting tips Materials / foams Software / tool My setup

Browse answers by topic below, or use search. New to the tool? See how cncfoam.com compares to GMFC, DevFoam & JediCut, or read the hot-wire foam cutting wiki.

Category G-code · 8 matches. Clear filters.

What G-code does a hot-wire cutter actually use?

A small, friendly subset. Almost everything is G1 linear moves (coordinated straight cuts) with a feedrate — there are no arcs or tool changes. A hot-wire job is basicall…
What do M3/M5 and M8/M9 mean on a foam cutter?

They are the wire on/off switches, borrowed from spindle and coolant codes. M3 (spindle on) or M8 (coolant/flood on) is repurposed to energise the hot wire, and M5/M9 tur…
What are the X Y U V axes and how do they map to my machine?

On a 4-axis hot-wire cutter the wire stretches between two towers. X and Y drive one tower end (depth and height), and U and V drive the other end independently. When X/Y…
Why is there a pre-heat dwell (G4) at the start of the file?

A cold wire tears foam and bows badly. The G4 dwell is a short, deliberate pause right after the wire is switched on, before the first cut, that lets the wire reach cutti…
Why does cncfoam.com only emit G1 moves and never rapid G0?

Because a hot-wire cutter has no safe 'rapid' — the wire is always hot and always in or near the foam, so a fast G0 positioning move would race the wire cold-or-hot throu…
How do I convert cncfoam.com G-code to my controller's axis letters?

Use the tool's G-code profile / axis remap at download. The library and tool keep motion in canonical X Y U V (plus A for rotation), but many controllers expect different…
What feedrate should I put in the G-code?

Feedrate is tied to wire heat — they must balance. There is no universal number; it depends on foam density, wire temperature and gauge. A practical starting window for E…
Can I hand-edit the G-code, and what should I never change?

You can — it is plain text — but tread carefully. Safe edits: tweaking the feedrate (F), adjusting the pre-heat dwell, or fixing axis letters to match your firmware. Risk…

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