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PROFINET Recipe Transfer
Understand what sharing recipe data with the line controller means in operational terms.
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Edge Quality in Nonwoven Lines
How the slit edge affects product quality in hygiene product manufacturing, and how an alignment error turns into scrap. We work out what a small deviation adds up to by the end of a shift.
Process assessment
A laser reference makes the cutting process visible; on its own it does not create edge quality
- Web tension, blade geometry, wear, material weight and line speed must be assessed together.
- Calculate the scrap effect from the product recipe and shift data, not from assumptions.
- Verify laser colour and optical power on a real material sample.
The materials slit on hygiene product lines — nonwoven, tissue, elastic tape — behave far less forgivingly than woven fabric. A nonwoven edge does not lock as soon as it is cut; the fibre structure starts to loosen from the cut line onwards.
That is why edge quality on nonwoven lines is not a cosmetic question but one of process stability .
How does an alignment error become scrap?
The chain works like this:
- The blade runs in a shifted positionWhen the cut line deviates a few millimetres from the target, one slit comes out narrow and its neighbour wide.
- The narrow slit falls outside toleranceSlit width tolerances on hygiene product lines are usually tight; a slit below the limit cannot be used at the next station.
- The wide slit is wasted materialEven if it stays within tolerance, the excess material is a loss repeated on every metre.
- Edge fraying increasesIf the blade cuts the material at a point outside the designed tension profile, fibre breakage becomes irregular and the edge frays.
- The problem grows at the next stationA frayed or out-of-tolerance edge causes feeding faults at the winding and bonding stations — and that is where the production line remains idle.
A simple calculation
On a two-metre-wide line, a 2 mm alignment deviation is a 0.1% material shift per slit. That sounds small. But the deviation repeats on every metre and is multiplied by the number of slits.
On a line running at 200 metres a minute, roughly 96,000 metres of material pass in an eight-hour shift. The loss from the deviation may look modest on its own, but it repeats every shift — and it usually goes unmeasured.
Two different alignment problems
Two separate jobs on nonwoven lines often get confused:
| Problem | What is done | What is needed |
|---|---|---|
| Blade alignment | Positioning the cutting elements according to the recipe | A laser reference line for every blade position |
| Reel alignment | Placing the incoming reel relative to the centre and the edge | A centre reference and edge reference lines |
Most lines need both. Blade alignment happens at setup; reel alignment repeats at every reel change. Because the second job is far more frequent, having the reference stay on throughout production becomes critical there.
Why multiple reference lines are needed
On lines with few slits, projecting the reference lines in sequence is enough: the operator sets the first blade, the system moves to the second position, that blade is set, and so on. As the slit count grows, this method runs into two problems.
- Setup time grows. On a twenty-slit recipe, sequential display puts the operator through the same cycle twenty times.
- The ability to check at a glance is lost. If the reference lines are not all visible at once, there is no way to confirm at a glance that the slit widths are consistent with each other.
The architecture decision changes here: up to six projected laser lines Core Precisor, and beyond that — where simultaneous visibility is required — Shuttle Precisor.
Surface and colour
Nonwoven is usually light-coloured and matte — a favourable background for reading a laser line. On very light, diffusely reflecting surfaces such as tissue, however, the line can look “spread out”. On elastic and ear-feed materials the surface can be glossy, and the reflection becomes uncomfortable for the operator.
That is why we test laser colour on a material sample during the survey rather than picking it from a catalogue.
In short
On nonwoven lines, alignment is not a quality-control step but a quality-creating one. Cutting the edge in the right place affects every station downstream, and the accuracy and continuity of the alignment reference show up directly in the scrap rate.
WHAT DOES YOUR LINE NEED?
Share your alignment requirements and we will assess the laser layout, the motion architecture and the automation interfaces for your application together.
GET IN TOUCHFor short definitions of the terms used in this article, see the alignment glossary .