Matrix stripping describes the process-reliable removal of the waste matrix after die cutting or kiss-cut. The waste web is separated from the useful contour and wound up separately. The parts remain in an ordered arrangement on the liner or are transferred to downstream steps. In simple terms: the matrix is what is not needed. Matrix stripping ensures that only the clean, dimensionally accurate parts remain.
In the electrical insulation industry, matrix stripping is decisive because pre-cut insulating parts and adhesive geometries have to be reliably supplied. It influences cycle time, scrap, particle generation and dimensional accuracy. Especially with polyimide, polyester, Nomex and technical adhesive tapes using acrylate or silicone adhesives, matrix stripping defines the process window.
Process principle and equipment components
In the kiss-cut, the tool separates cover material and adhesive. The liner remains intact. Immediately afterwards, the coherent waste matrix is stripped away with defined tension and geometric guidance. Core components are:
- Cutting station: rotary or flatbed tool, for rotary often a magnetic cylinder with flexible die
- Stripping station with deflection angles, pressure rollers and stripping rollers
- Waste winder for the stripped matrix
- Web guide with web edge control, dancer and tension control
- Optionally vacuum drum and air jets for delicate contours
What matters is the harmonisation of cut quality, web run and stripping parameters. Only when clean cut edges and a consistently guided web come together does the matrix release without tears or lost parts.
Critical parameters in matrix stripping
Geometry and design for converting
- Dimension web widths and minimum webs between usable parts sufficiently
- Inside radii instead of sharp corners reduce notch cracks in the matrix
- Respect orientation to web direction, with long webs parallel to the pulling direction
- Place hold points or micro-web features deliberately to keep parts securely on the liner
Material system
- Cover material: polyimide, PET, PVC, Nomex, technical nonwovens
- Adhesive system: acrylate for ageing resistance, silicone for high temperature and low-energy surfaces, rubber for high initial tack
- Liner: siliconised papers as standard, PET liners for high temperature and precision requirements
Cut quality
- Blade setting, cutting gap and tool sharpness determine fibre pull-out, burr formation and dust
- With laser kiss-cut, minimise heat influence so that adhesive does not smear and the matrix releases cleanly
Stripping parameters
- Choose peel angle between shallow and steep depending on the material
- Stabilise peel speed and tension via dancer control
- Take process temperature into account, as adhesion values are temperature-dependent
- Use ionisation to prevent static charge and parts lifting off
Quality, tolerances and measurement practice
A good matrix stripping result is characterised by burr-free edges, an undamaged liner and parts that remain stably in place. Relevant inspection criteria:
- Dimensional accuracy of contours, often with inline optical inspection
- Release force and re-release behaviour of the parts from the liner
- Low particle and dust levels, visible in light-coloured adhesive zones and on the liner
- Edge quality without tear-outs, particularly on fibrous substrates such as Nomex
General tolerances per DIN ISO 2768 typically apply to geometric requirements. In addition, process-specific attributes such as register accuracy, web run and process capability indicators are documented. For sensitive applications, SPC monitoring of tension, temperature and web edge is recommended.
Applications in electrical, automotive and electronics
- Insulating parts from films: polyimide (Kapton) for high temperature, polyester (HOSTAPHAN or Mylar) for general insulation tasks, Nomex (aramid paper) as a thermally stable carrier material
- EMI and thermal management: conductive films, shielding laminates, thermal pads as kiss-cut geometries
- Labels and masks: masking for coating and soldering processes, ESD labels, traceability labels
- Sealing and damping contours: PTFE, POM and nonwoven materials as functional cut parts
In all cases, matrix stripping ensures that delicate parts in roll-to-roll processes are provided in an ordered, assembly-ready manner.
Advantages of stable matrix stripping
- High cycle rates thanks to continuous roll processes
- Clean edges, less rework and a lower complaint rate
- Reliable part retention on the liner until assembly
- Lower particle generation with an optimised cutting and stripping strategy
- Good interaction with automation concepts such as pick-and-place
Typical challenges and troubleshooting
- Liner damage: reduce tool pressure, adjust blade setting, consider a harder PET liner
- Part loss during stripping: enlarge webs, change peel angle, optimise adhesion balance between cover and liner
- Adhesive strings and smearing: adjust cutting speed, reduce laser power, cool the process
- Cracks in the waste matrix: increase inside radii, respect fibre orientation of paper or nonwoven carriers, lower tension
- Particle formation: sharpen tools, use anti-static and extraction, check material combinations
A structured DoE across peel angle, tension, temperature and speed identifies robust parameter windows. For variant production, a tool strategy with flexible dies and standardised setup recipes is worthwhile.
Selection criteria for procurement and design
- Material combination of cover, adhesive and liner suited to the application
- Geometry with sufficient web widths, defined inside radii and hold points
- Process route: rotary or flatbed die cutting, laser kiss-cut for frequent design changes
- Quality concept with inline camera, tension monitoring and documented stripping recipes
- Cleanliness concept: ionisation, extraction, suitable cleaning intervals
- Economics: tool strategy, setup times, contract slitting for small batch sizes
GOBA Takeaway
Matrix stripping is far more than unwinding waste. It is a central quality and productivity feature in the converting of films, adhesive tapes and insulating parts. Those who design geometry, material system, cut and stripping parameters as a complete system achieve stable processes with high cycle rates, clean edges and secure part retention. For engineering, purchasing and quality, this means: consider webs, inside radii and liner choice already in the design phase, work with controlled tension and peel angles in production, and verify the results with inline optical inspection. In this way, matrix stripping becomes the enabler of reproducible premium kiss-cut quality.