What a hygiene line actually cuts

A diaper or sanitary napkin line is a stack of materials moving at speed: spunbond and meltblown nonwoven for the top sheet, film for the back sheet, tissue and SAP for the absorbent core, elastics, and hot-melt adhesive holding it all together. The blade has to cut through that stack cleanly, at every station, without dragging the layers apart. That is a different problem from cutting a single web, and it is why hygiene blades wear and fail in their own way.

Where the blades sit on the machine

• Cross-cut knife and anvil — separates one product from the next, usually against a hard anvil
• Slitting knives — trim the web to final width, top and bottom in pairs
• Edge trim and side-seal trim — removes the fused edge after the sealing station
• Ear and side-panel knives — cut the shaped profile on the sides
• Perforating and tear-line blades for reclose features

Why nonwoven is harder to cut than film

Film cuts by shear: the blade separates the material and the edges stay where they are put. Nonwoven is a web of filaments, and a dull edge does not cut those filaments — it drags them. The result is a fuzzy edge, loose fibre at the cut, and dust that migrates into the machine. On a hygiene line that fuzz matters more than on most others, because the cut edge is often a product edge the customer sees and touches.

The second problem is hot-melt adhesive. It builds up on the blade face, changes the effective edge angle, and starts pulling fibre instead of cutting it. A blade that was fine last week can feel blunt today with almost no wear on the edge itself.

Where a hygiene machine blade fails

• Fuzzy or stretched cut edge. Edge rounded, or clearance opened up so the blade drags instead of shears.
• Adhesive build-up on the face. Not wear. Clean it before ordering a new blade — the difference in cut can be dramatic.
• Product not separating at the cross-cut. Anvil wear or the knife not reaching full stroke, before the blade is at fault.
• Chipping at the tooth or corner. Impact with a splice, a wrinkle, or a doubled layer.
• One lane out of tolerance while the rest are fine. That station’s spacer or bottom ring, not the whole set.

Steel and edge for hygiene lines

Most of these blades run in tool steel or high-speed steel, and the choice is driven by what is being cut: an abrasive air-through nonwoven wears an edge faster than a smooth spunbond, and a line running at high speed needs an edge that holds its geometry rather than one that starts sharpest. For lines that are washed down or run in humid conditions, stainless is the starting point. We will not claim a food or medical grade on your behalf — if a specific standard applies, tell us and we confirm before the order.

How we match an existing blade

Send the worn blade, or a drawing. We measure the outside dimensions, the edge angle, the mounting and, for a cross-cut knife, the tooth pitch and anvil interface. Tell us which station it came from and what the failure looked like: fuzzy edge, adhesive build-up and chipping each point to a different answer, and quoting without that information usually produces a blade that fails the same way.

Hygiene blade questions

Can you match blades for a machine we bought second-hand?

Yes, that is common. Send the worn blade plus the machine make and model if you know it. If the blade is missing, send the drawing from the machine manual or a photo of the station and we will tell you what we need.

The cut edge is fuzzy but the blade looks fine. What is it?

Usually adhesive on the blade face, or clearance set too loose. Both make the blade drag fibre instead of shearing it. Check those two before spending money on steel.

Do you supply the anvil as well as the cross-cut knife?

Yes, as a pair. A new knife on a grooved anvil will not separate product properly, so we prefer to quote them together.