What blade do I need for cutting foam?

A bandknife, not a toothed bandsaw blade. Foam tears under teeth, so the right tool is a continuous honed knife edge that slices the block cleanly with no dust and no kerf loss. Dakin-Flathers' Slicer37 is the usual starting point for foam converting, welded to your machine's loop length in the UK.

Can I cut memory foam with the same blade as ordinary foam?

Yes, memory foam is cut with a bandknife like other polyurethane foams. It rewards the same discipline: a keen edge and a steady feed, because it compresses and recovers unevenly if forced. For contoured shapes, narrow CNC contour band knives are made to profile soft, rigid and memory foam.

Will one blade handle foam, insulation and packaging materials?

Often, yes. Bandknife blades slice foam, insulation, leather, textiles and packaging materials, so one edge can cover a mixed workload. Denser sponge, scourer and packaging stock is better served by a lightly toothed bandknife that bites where a plain edge drags. Tell us the machine and the material and we will match the blade.

Material guide

Bandknife blades for cutting foam

Foam is cut, not sawn. A honed bandknife edge parts PU, memory and rebond foams cleanly with no dust and no kerf loss, with toothed bandknives keeping the cut moving in denser grades.

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The problem with cutting foam

Put a toothed bandsaw blade into a block of PU foam and the teeth do not cut it so much as tear it. Foam is soft, elastic and full of air, so it deflects around each tooth instead of shearing, then springs back torn. The result is a ragged face, a snowstorm of crumb and a kerf of material lost on every pass. On memory foam the problem is worse: the material grabs, compresses and recovers unevenly, leaving a wavy cut that scraps the piece.

The right tool is not a saw at all. A bandknife is a thin continuous knife edge (toothless or lightly toothed) honed sharp so it parts the cell structure in a single slice. On a toothless edge there is nothing for the foam to snag on, no dust and no kerf loss: the blade separates the block rather than machining a slot through it.

Edge profile then follows density. Soft PU foams slice cleanly on a straight edge, while rigid grades call for a scallop edge that bites in rather than skating over the surface, with wavy edges covering the densities between. At the top of the density range, lightly toothed bandknives bite into medium and high density foam that grips and drags on a plain edge.

Recommended blades for foam

Constructions and ranges from the manufacturers' published data, with the honest reason each blade makes the list. Every one is welded to your machine's length.

Recommended blades for foam, drawn from the manufacturers' published ranges. Prices are from prices per welded loop, ex VAT, at the narrowest width and shortest length.
Blade	Construction	Width range	Why this blade	From price
Slicer37 Bandknife BladeDakin-Flathers Slicer37	Thin, toothless or lightly toothed continuous knife edgeBandknife Blades guide	10mm to 100mm	Dakin-Flathers' straight-edge bandknife with no teeth slices foam cleanly with no kerf and no dust, the starting point for foam converting.	From £26.50 ex VATsample pricing
CNC Contour Band KnivesDakin-Flathers Slicer37 CNC	Thin, toothless or lightly toothed continuous knife edgeBandknife Blades guide	3mm	These narrow Slicer37 knives are sized for tight profile work, cutting soft, rigid and memory foam into contoured shapes on CNC machines.	From £29.50 ex VATsample pricing
Slicer37 Toothed BandknivesDakin-Flathers Slicer37	Thin, toothless or lightly toothed continuous knife edgeBandknife Blades guide	10mm to 32mm	Lightly toothed Slicer37 bandknives bite into medium and high density foam, sponge and scourer stock that grips and drags on a plain knife edge.	From £28.50 ex VATsample pricing

Getting the cut right

General rules that hold across machines. Exact widths, pitches and options are on each product page.

Match edge form to density
Foam density decides the edge profile. Soft PU foams part cleanly on a straight edge. Denser and rigid grades need a wavy or scallop edge that grips the surface and starts the cut instead of skating across it. If the face tears or the cut wanders, the edge form is usually wrong for the grade.
Keep the edge honed
A bandknife parts foam by sharpness, not force. As the edge dulls it starts to drag. Drag shows up as a torn face, crumb and a cut that wanders off line. Hone or regrind the edge as soon as the finish deteriorates rather than pushing on; a keen edge is the whole difference between slicing and tearing.
Let the knife do the work
Foam compresses under pressure, so forcing the feed squashes the block against the edge and the cut recovers wavy once the material springs back. Feed steadily and let the knife slice at its own pace. Memory foam in particular rewards a patient feed: rushing it distorts the block and the finished dimension with it.
Choose knife or wire
Straight slitting and splitting of blocks suits a wide bandknife. Tight contoured shapes in soft, rigid or memory foam call for a narrow CNC contour knife, while medium and high density grades want a lightly toothed edge that keeps the feed moving. Match the blade to the machine and the shape you are cutting, not just the material.

Suggested image

Action shot: recommended blade cutting foam, cut face visible

materials/foam/cutting

Industry guide

Foam, Insulation and Packaging Conversion

Cutting foam for a living? The industry guide maps the whole workload, not just this material.

Read the guide

Other material guides

Frequently asked questions

Tell the wizard your machine and length and it will match foam to a blade that fits.

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