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    Creasing Matrix Selection & Calculation Guide (2026): Formulas, Types and Cracking Fixes — Technical Knowledge | All-in Pack
    Technical Knowledge

    Creasing Matrix Selection & Calculation Guide (2026): Formulas, Types and Cracking Fixes

    October 18, 2026By , Technical Director5 min read
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    How to size a creasing matrix from board caliper and rule thickness, when to choose PVC, resin, fibre, reverse-bend or coil matrix, and a step-by-step fix list for cracked, weak or off-register creases in die-cutting.

    Table of Contents
    1. What does a creasing matrix do?
    2. How to calculate creasing matrix size
    3. Quick size chart (2 pt / 0.71 mm crease rule)
    4. Creasing matrix types compared
    5. How to fit a creasing matrix (step by step)
    6. Crease cracking and other faults: troubleshooting
    7. Matrix, rule and rubber: the full die-cutting setup
    8. Frequently Asked Questions

    By Gavin Gao — 15+ years in foil stamping and post-press supply at All-in Pack. Reach me at sales@allinpacks.com.

    Quick answer: A creasing matrix is the pre-formed channel strip fixed to the counter plate of a die-cutter so a crease rule can press a clean fold line into board. For folding carton, size it with two starting formulas: channel width = 1.5 × board caliper + rule thickness and channel depth ≈ board caliper, then confirm with a test crease.

    Most crease problems on the press — cracked folds, weak creases that spring back, cartons that won't square up on the folder-gluer — come back to three choices: the matrix size, the matrix material and how it was fitted. This guide covers all three, from the supplier side.

    PVC creasing matrix strips for die-cutting counter plates

    What does a creasing matrix do?

    A creasing matrix gives the crease rule a defined channel to push the board into. Without it, the rule simply flattens fibres against a hard plate and the fold line is weak and unpredictable. With the right channel, the board is displaced into a controlled bead on the reverse side, which becomes the hinge of the fold.

    Each matrix has three parts that matter:

    • Base (carrier) strip — usually adhesive-backed, sets the overall height.
    • Channel — the groove width and depth that shape the bead.
    • Locating strip (plastic guide) — keeps the channel centred on the rule during fitting, then is peeled away.

    How to calculate creasing matrix size

    These formulas are the common industry starting point for folding carton and solid board. They are rules of thumb, not guarantees — board fibre, coating and moisture all shift the result.

    Parameter Starting formula Example: 0.40 mm board, 0.71 mm (2 pt) rule
    Channel width 1.5 × caliper + rule thickness 1.5 × 0.40 + 0.71 = 1.31 mm → use 1.3 mm
    Channel depth (matrix height) ≈ board caliper ≈ 0.40 mm
    Crease rule height Cutting rule height − board caliper 23.80 − 0.40 = 23.40 mm

    Quick size chart (2 pt / 0.71 mm crease rule)

    Board caliper Typical board Channel width Matrix height
    0.30 mm 230–250 gsm folding boxboard 1.2 mm 0.3 mm
    0.40 mm 300–350 gsm SBS / FBB 1.3 mm 0.4 mm
    0.50 mm 400 gsm board 1.5 mm 0.5 mm
    0.60 mm heavy board / lined chipboard 1.6 mm 0.6 mm
    0.80 mm rigid board, E-flute micro 1.9 mm 0.8 mm

    Round to the nearest stock width your supplier carries. For corrugated (E, F, B flute) the flute crushes differently; plants typically widen the channel further and test on the actual board rather than relying on the solid-board formula.

    Two adjustments worth making:

    1. Against the grain: creases running across the grain often need the next wider channel.
    2. Laminated, foil-stamped or heavily varnished boards: the surface layer is less elastic than the board — go one width wider or slightly shallower to protect the print. If you also hot foil stamp the same carton, crease after stamping and check the foil at the fold.

    Creasing matrix types compared

    Type Best for Strength Watch out for
    PVC creasing matrix (AP-PM) Short–medium runs, standard folding carton Low cost, easy to fit, wide size range Channel wears faster under high pressure
    Resin / fibre creasing matrix (AP-RM) Long runs, heavy board, high-speed automatic die-cutters Holds channel profile longer, fewer re-make-readies Higher unit cost
    Reverse-bend creasing matrix (AP-RB) Flaps and partitions folding away from print Clean reverse fold without cracking the face Must match rule position precisely
    Creasing matrix coils (AP-CR) Many jobs, frequent make-readies Cut exact lengths on press, less waste Needs a clean cutting tool and fitting discipline

    Resin and fibre creasing matrix profiles

    Simple selection rule: start with PVC; move to resin or fibre when the job is long, the board is heavy or your press runs fast enough that matrix wear becomes the reason you stop. Use reverse-bend only where the fold direction requires it.

    How to fit a creasing matrix (step by step)

    1. Clean the counter plate of old adhesive and dust.
    2. Cut matrix lengths with a square, clean cut; mitre the corners where creases meet.
    3. Slide the locating strip over the crease rule so the channel sits centred on it.
    4. Peel the adhesive liner and close the press gently to transfer the matrix to the plate.
    5. Remove all locating strips before running.
    6. Run a test sheet, fold it by hand and on the folder-gluer, then fine-tune make-ready.

    Crease cracking and other faults: troubleshooting

    Symptom Likely cause Fix
    Outside of fold cracks Channel too narrow or too deep; rule too high; dry board; folding against grain Widen channel one size, reduce rule height or make-ready, condition board to ~45–55% RH
    Crease weak, carton springs open Channel too wide or too shallow; rule too low Narrow channel or raise matrix height; add make-ready under the rule
    Crease off-centre or doubled Matrix not centred on rule; locating strip left on; plate shifted Re-fit with locating strip; check plate register
    Print or foil cracks at fold Surface layer less elastic than board Wider channel, consider reverse-bend matrix, crease with the grain where possible
    Channel wears quickly PVC on a long or high-pressure job Switch to resin / fibre matrix
    Board tears at crease ends Matrix ends not mitred; cut rule and crease rule too close Mitre ends cleanly; check die layout at junctions

    Matrix, rule and rubber: the full die-cutting setup

    A clean crease is a system, not a single part. The matrix only works if the steel rule heights are consistent, the ejection rubber releases the sheet without pulling the crease, and gap filler sponge and rubber strips keep the sheet flat as it leaves the die. If you are specifying a new press, see our automatic flatbed die-cutting machine.

    Browse the full range of post-press consumables, or send us your board caliper, rule thickness and run length and we will recommend matrix sizes and send samples.

    Get a creasing matrix quote →

    Frequently Asked Questions

    Quick answers about creasing matrix.

    For folding carton, start with two rules of thumb: channel width = 1.5 × board caliper + crease rule thickness, and channel depth ≈ board caliper. Example: 0.40 mm board with a 0.71 mm (2 pt) rule gives a 1.31 mm channel, rounded to the nearest stock size of 1.3 mm, and a 0.4 mm depth. Always confirm with a test crease on the actual board.

    PVC creasing matrix is the economical choice for short and medium runs and standard folding carton. Resin or fibre-reinforced matrix holds its channel profile longer under high pressure and high speed, so it suits long runs, heavy board and automatic die-cutters where re-make-ready time is expensive.

    Outside cracking usually means the channel is too narrow or too deep for the board, the crease rule is too high, or the board is folding against the grain or is too dry. Widen the channel one size, reduce rule height or make-ready, check grain direction and condition board to roughly 45-55% relative humidity.

    Use reverse-bend matrix when a panel must fold away from the printed side, for example tuck flaps or inner partitions. Its profile creates the crease from the opposite face so the board folds cleanly in the reverse direction without cracking the print or coating.

    Coil matrix reduces waste and lets operators cut exact lengths on the press, which suits plants with many jobs and frequent make-readies. Pre-cut strips are faster to apply for repeat jobs with standard lengths. Profile, height and channel width matter more than the format.

    Companion Products

    Specs and samples for the products discussed in this article.

    AP-PM PVC Creasing Matrix for Die-Cutting — All-in Pack
    Creasing Matrix

    AP-PM PVC Creasing Matrix for Die-Cutting

    PVC-base self-adhesive creasing matrix in standard, narrow, wider, off-centre and double-crease profiles for crack-free folds.

    View product
    AP-SR Steel Rule Cutting Blade for Die Boards — All-in Pack
    Die-Cutting Consumables

    AP-SR Steel Rule Cutting Blade for Die Boards

    Hardened steel rule for cutting and creasing die boards — consistent bevel, straight running, long edge life.

    View product
    Tags:
    creasing matrix
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    PVC creasing matrix
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    die-cutting consumables

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