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What wall thickness does your paper core need?
How much wall do you really need?Not a millimetre more, not a millimetre less. Let’s work it out.
🏆 Starting from the you found in the game.
Your full report is ready. Where shall I send it?
I’ll show you the exact wall, the weight per metre and the outside diameter right here and email you a copy. One email only, no automatic sign-up.
Safety margin 1.5×, moisture 8%. One board grade up often costs less than an extra millimetre of wall.
ROLL Lab estimate, not a test certificate. Request a test on the real core →
How the calculation works
The ROLL Lab estimates flat crush with a power law on wall thickness, fitted to ROLL Lab reference estimates on 3" cores, and radial crush with the thick-walled tube formula, fitted to the same data; it then finds by bisection the minimum wall that meets the target times the margin.
The result is a design figure: it helps you choose between two walls or two grades and see what one grade up is worth. It does not replace a test on the real core.
Frequently asked questions
How do I choose the right wall thickness?
Start from the strength you need, not from the wall. For film, radial strength matters: how well the core withstands the squeeze of the roll. For heavy reels, flat crush and bending matter. The ROLL Lab calculator "How much wall do you really need?" gives the minimum wall for a strength target.
What affects the strength of a paper core?
Wall thickness, board grade, diameter, moisture, strip width and winding angle, adhesive type (silicate or dextrin) and the age of the core. Moisture is the strongest lever, and the only one that keeps changing after delivery.
Sources
- ISO 11093-9
- ROLL Lab calculation
The other lab apps
How much does your core weigh?
Weight per metre, weight per piece, pieces and metres per tonne.
base🔁Every unit, one language
Convert flat crush resistance between the units suppliers use.
base💧The sweating core
From warehouse humidity to lost strength: flat, radial, stiffness.
base🌡️Longer in summer, tighter in winter
How length and diameters change with humidity, season by season.
base📏Pass or fail?
Check the inside diameter against ISO 13542 tolerances.
prof🌀Will your core hold?
Radial duel: roll pressure against the radial strength of the core.
base⚔️Paper or plastic? Let’s do the sums
Weight, strength, reuses and cost per use of 7 materials.
prof🚚How many cores in the truck?
Cores per pallet and per vehicle, with staggered rows and the container door.
prof🩺Why are your cores collapsing?
Dr. Core: the likely causes of crushed or loose winding cores.
prof♻️Where your core goes at end of life
Tonnes per year, EWC codes, recycling route and a sheet for your plant.