If you come from CNC milling, 5-akset means five motors moving på samme tid in smooth, interpolated harmony to swing a cutter all around a part. Hot-wire foam cutting does not work that way — and it is worth being precise about what a "5-axis foam cutter" actually is, because the name promises something the physics never delivers.
It is really two machines in one
Every hot-wire cutter lives under one hard constraint: the tool is a straight wire stretched between two ends. A straight line can only ever sweep a styret overflade — so no hot-wire machine, with any number of axes, can carve a true freeform 3D blob in a single pass. Everything is built from straight-wire sweeps. Two machine families fall out of that:
- 4-axis (X, Y + U, V) — two independent towers, one at each end of the wire. Because each end can trace a different profile, the wire blends (morphs) from one shape to another along its length: a wing that is one aerofoil at the root and another at the tip, a square-to-round duct, a tapered and twisted column. See Morfing af to profiler.
- 3-axis (X, Y + A) — a single tower plus a rotary turntable/lathe axis. You cut a profile, rotate the foam by a set angle, cut again, and so on. See Rotationsakse & indekserede snit.
En 5-axis machine simply has all five motors (both towers og the rotary), so it can behave as either machine — or both, within one job. That is the whole idea: 5-axis = 4-axis + 3-axis, combined.
| Mode | Axes driven | What it does |
|---|---|---|
| 2-akset | X, Y (U/V mirror X/Y) | Straight extrusion of one profile. |
| 3-akset | X, Y + A | One profile, indexed-rotated between passes. |
| 4-akset | X, Y, U, V | Independent towers → morph between two profiles. |
| 5-akset | X, Y, U, V + A | Either of the above, switchable within one cut. |
Why there is no "true" simultaneous 5-axis in foam
Because the wire is straight, spinning the part on the A axis mens both towers morph independently buys you almost nothing — the wire still only ever cuts a ruled surface at any instant — and it makes the motion planning enormously complex for no real-world gain. So in practice every foam part is built as a stack of ruled-surface passes with rotations between them, and rotation is virtually always indekseret: cut a face, stop, rotate by a fixed angle, cut the next face.
That is the honest state of the craft: there are essentially no true 5-axis, simultaneously synchronized foam cuts in the wild — only a few highly specialized edge cases (helical/auger flights, a profile turned while the wire feeds, and similar lathe-like tricks). For 99% of work, "5-axis" means indexed rotation plus independent towers, not five interpolated axes.
So why generate 5-axis G-code on a rotation cut at all?
This is the subtle, important part. An indexed rotation cut is conceptually a 3-axis job (X, Y + A). But on a dual-tower machine you kan ikke just drive X and Y and leave U and V parked. If you did, only one end of the wire would move — the other end would sit still, the wire would skew and go slack, and the cut would be ruined.
The wire has to stay straight and square to the rotary axis through the whole pass, which means both towers must ride in unison: the U/V end mirrors the X/Y end, move for move, so the two ends arrive together and the wire stays true. Driving X, Y, U og V together, plus the A rotation between passes, is — by axis count — 5-axis G-code, even though the finished result is an indexed, 3-axis-style cut.
X Y U V A on a rotation cut so the towers stay synchronized during the cut and the index — not because the part needs five interpolated axes. The "5th axis" in the G-code is bookkeeping that keeps the wire straight.The other reason: switching modes without re-rigging
Because the hardware and the G-code system both carry all five axes at once, a single job can flip between modes without reconfiguring the machine: run an independent-tower morph pass (X/Y and U/V cutting different profiles), then an indexed-rotation pass (towers in unison + an A rotate), then another morph — all in one file, one setup. The 5-axis system is the union of the 3-axis and 4-axis capabilities, instantly available, so you switch fast between indexed cuts and independent-tower cuts mid-part.
What "true 5-axis" hardware actually needs
- Two independent X/Y towers — four motors (X, Y on one tower, U, V on the other), built identical and dead parallel so the wire stays square. See Maskintyper.
- A rotary A axis — a turntable (vertical) or lathe-style (horizontal) rotary as the fifth motor, with the foam centred on the axis so it spins in place rather than orbiting.
- A controller that drives all five together — e.g. an ESP32 running FluidNC, which handles the extra axes natively over one config file. Older 3-axis GRBL boards cannot.
- A G-code generator that emits coordinated
X Y U V A— keeping the towers in unison on rotation passes and independent on morph passes. That is exactly what cncfoam.com produces.
How cncfoam.com handles it
Indstil Maskintype to 5-axis (X/Y + U/V + ROT) and you get the morph workflow og the indexed-rotation workflow together. On a rotation cut, cncfoam.com makes the U/V tower mirror the X/Y tower so the two ends ride in unison and the wire stays straight, and it inserts an A<degrees> command between stages to index the foam. On a morph pass the towers run independently. The exported file therefore speaks full canonical X Y U V A, which you can remap to your controller's axis letters at download. See Multi-aks G-code og Rotationsakse & indekserede snit.
Summary
- En 5-axis foam cutter = 4-axis (X, Y, U, V) + a rotary (A) axis — two capabilities, not five interpolated axes.
- Foam rotation is virtually always indexed (cut → rotate → cut), not simultaneously synchronized; true 5-axis foam cuts barely exist outside niche edge cases.
- We still emit full
X Y U V Aon a rotation cut so both towers ride in unison and the straight wire never skews. - Carrying all five axes at once lets one job switch instantly between indexed-rotation and independent-tower morph cuts.