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Crushed cores or rolls stuck on the shaft: the causes in 9 questions
Why are your cores collapsing?Tell me the symptoms: in nine questions I’ll find the culprit.
🏆 Starting from the you found in the game.
Your full report is ready. Where shall I send it?
I’ll show you every cause in order of likelihood, with the checks to make right here and email you a copy. One email only, no automatic sign-up.
ROLL Lab estimate, not a test certificate. Request a test on the real core →
How the calculation works
The nine questions follow the checks a technician makes before blaming the core: the winding process, film down-gauging, when the failure appears (cast within 72 hours, blown within 7 to 14 days), warehouse relative humidity, season, changes of supply, the age of the samples being compared, the specification and the measuring method.
Frequently asked questions
Why does an "identical" core from another supplier fail?
Because "identical" often means only the same diameter and the same flat crush. Two cores with the same flat crush can have very different radial strengths, and moisture on delivery and the age of the core matter too. A comparison only makes sense with the same test method, moisture and age.
Why do cores go loose in winter and collapse in summer?
In winter, cold outside air heated indoors has low relative humidity: the core gives off water, shrinks and slips inside the roll. In summer, warm humid air makes the core absorb water and lose radial strength: the inside diameter closes up and the roll gets stuck on the shaft.
Is flat crush enough in a specification?
No, not if the core goes under a film roll. Flat crush barely reacts to the variables that drive radial strength: across moisture and core construction it moves 3 to 25 times less than ID stiffness. A useful specification also states the minimum radial crush in bar and the test method.
Sources
- CCTI T-158 and T-159 — Radial crush test
- ISO 11093-3 — moisture content by oven drying
- 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.
prof🧱How much wall do you really need?
From the strength you need to the minimum wall thickness.
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♻️Where your core goes at end of life
Tonnes per year, EWC codes, recycling route and a sheet for your plant.