Short answer: a heavy-duty cardboard core is needed when the roll is heavy and long, is wound at high speed and tension, or is stored in several layers. It is selected by inner diameter, wall and crush resistance. We produce cores from ∅28 to ∅250 mm, with a wall of 2-15 mm and a crush resistance of 1.4 to 15.2 kN.
In the production of technical films, membranes or fabrics, a cardboard core is not an add-on to the roll. Its diameter, wall and strength determine whether the roll winds evenly, whether it survives transport and storage, and whether it fits securely onto the machine shaft at the customer's site. As a manufacturer of cardboard cores and stretch film, we select cores for rolls ranging from light films to heavy membranes. Below we describe what we look at in such a selection.
Cardboard, paper or carton cores?
In the packaging industry the same product goes by several names: cardboard cores, paper cores, carton cores or simply cores. They are cylindrical cores made of multi-layer cardboard, not corrugated board, onto which film, paper, tapes, fabrics and other materials are wound. We use the name "cardboard cores", but if you are looking for a manufacturer of paper cores, we are talking about the same thing.
Cardboard cores are used in many industries. From our table: ∅28-50 mm cores have a hygiene certificate and are used for food films, ∅76 mm for machine stretch film and printing, larger diameters for paper, fabrics, geotextiles and floor coverings, and the largest, up to ∅250 mm, for technical films, membranes, cables and coiled steel. Which core is right depends on the specific application, not on the name alone.
When is a heavy-duty cardboard core needed?
Heavy-duty cardboard cores differ from standard ones in their thicker wall and high crush resistance. You need them when:
- the roll is heavy and long, for example roofing membranes, construction films, geotextiles or floor coverings,
- the material is wound at high speed and high tension, so the core carries large forces already on the winder,
- the rolls are stored in several layers or for a long time, and go through several transhipments in transport.
For lighter rolls, narrower materials and slower lines, a core with a thinner wall is enough. The choice depends on the wall thickness, because it determines the stiffness and load capacity of the core. A thicker core "just in case" means more cardboard, more weight, a higher price and more waste after the roll is unwound.
Which parameters of cardboard cores for winding film matter most?
When ordering cores for technical films, six parameters matter. Changing one often forces an adjustment of the others, which is why we select them together, for a specific roll. For standard technical films an average wall thickness is often enough, but the final choice always depends on the weight of the roll.
Inner diameter
The inner diameter must fit the shaft or mandrel of the winder and of the customer's machine. A core that is too loose slips on the shaft, one that is too tight is hard to put on and take off. We produce cores with an inner diameter from 28 to 250 mm. The ∅76 mm core is used for machine stretch film, printing and heavier rolls. The largest cores, up to ∅250 mm, are used to wind technical films, membranes, geotextiles and coiled cables.
Wall thickness
The wall determines what roll weight the core can carry. We produce cores with a wall from 2 to 15 mm. A thicker wall is needed for a heavy and wide roll, high tension on the line and storage in several layers.
Length
We cut the core to the required length, matched to the material width and the margins on the winder. The cut length reaches 3200 mm.
Crush resistance
This is the most important measure of cardboard core strength. We test it on a laboratory press, on a 100 mm long sample, as the average of 10 measurements. The result in kN shows what roll weight and what storage method the core will withstand. Our values range from 1.4 kN at ∅28 mm to 15.2 kN at ∅250 mm.
Straightness and roundness
A bent or oval core runs out on the shaft. With wide rolls, even a slight deviation pulls the material to one side and spoils the roll edges. We check straightness along the entire length of the core.
Moisture
Cardboard reacts to moisture, and the dimensions and strength of the core depend on its moisture content. That is why we test it in every batch, and when selecting a core we also ask about the humidity of the hall where the winder operates.
Example cardboard core parameters
Below is an extract from our table (as of November 2026). We produce other diameters and walls to order, from the first batch.
Chart data in a table
| Inner diameter | Crush resistance |
|---|---|
| ∅28 mm | 1.4 kN |
| ∅45 mm | 2.6 kN |
| ∅50 mm | 3.3 kN |
| ∅76 mm | 6.1 kN |
| ∅100 mm | 8.4 kN |
| ∅150 mm | 11.7 kN |
| ∅250 mm | 15.2 kN |
| Inner diameter | Wall | Cut length | Crush resistance |
|---|---|---|---|
| ∅76 mm | 4-10 mm | up to 3200 mm | 6.1 kN |
| ∅100 mm | 5-12 mm | up to 3200 mm | 8.4 kN |
| ∅150 mm | 6-15 mm | up to 3200 mm | 11.7 kN |
| ∅250 mm | 8-15 mm | up to 3200 mm | 15.2 kN |
Can a thinner wall be just as strong?
Yes, if the material changes. A thicker wall is not the only way to a strong core. In the laboratory we look for a combination of cardboard and glue that gives the same crush resistance with a thinner wall. An example from our tests, a ∅76 × 600 mm core: an 8 mm wall made of mixed waste paper withstood 5.2 kN, and a 6 mm wall made of recycled cardboard 6.1 kN. The lighter core was stronger.
A lighter core can be stronger: with the same crush resistance, a core can weigh up to 20% less.
With the same crush resistance, a core can weigh up to 20% less. That means a lower price, a lower product fee and less waste after the roll is unwound. That is why in every selection we check whether the wall can be reduced before we propose a thicker core.
Cores for membranes and technical films: winding, transport, storage
The core works throughout the whole life cycle of the roll, not just on the line. When selecting a core, we ask about three stages:
- winding: winder speed, material tension and the weight of the finished roll,
- transport: vibration, transhipments and the way the rolls are secured,
- storage: the number of layers, storage time and whether the rolls lie flat or stand upright.
At each of these stages the core carries a different load, and we match the strength of cardboard cores to the most demanding of them.
How to prepare a core enquiry?
To select a core without several rounds of questions, prepare:
- Material type: technical film, membrane, fabric, paper.
- Material width and diameter of the finished roll.
- Roll weight and winder speed.
- Diameter and type of shaft.
- Method of transport and storage.
How you order cores from us
This is how ordering works:
- A conversation with our technologist: about 15 minutes on roll weight, winder speed, storage and humidity in your hall. You get a core proposal for your roll.
- Parameters in writing: we select the diameter, wall and crush resistance in kN based on laboratory tests.
- Test batch: you check the cores on your machine, with your roll. We start the series after your confirmation.
- Scheduled deliveries: we keep stock of your item in our warehouse and deliver it with our own transport. We deliver orders within 10 days.
We test every batch in the laboratory before dispatch: crush resistance, straightness and moisture content. You receive the results in writing, and repeatable parameters mean that every delivery has the same values as the approved test batch. For the customer's production process, this matters more than the nominal strength alone: cores that resist crushing in one batch and are weaker in the next mean damaged rolls and downtime.
Looking for a manufacturer of cardboard cores for technical films or membranes? See the full table of core parameters and send your specification in a request for quotation. We also offer stretch film and other packaging, so it is easier to buy everything from one supplier. We will select the core diameter, wall and crush resistance for your roll.
Frequently asked questions about cores for technical films
What are the largest cardboard cores you produce?
Cores with an inner diameter of up to 250 mm, a wall of up to 15 mm and a cut length of up to 3200 mm. In a flat crush test they withstand up to 15.2 kN. They are used for winding technical films, membranes, geotextiles and coiled cables.
How is the strength of a cardboard core tested?
We test crush resistance on a laboratory press, on a 100 mm long sample, as the average of 10 measurements. In every batch we also check straightness and moisture content, and we provide the results in writing.
How long does it take to fulfil a core order?
After the test batch is approved, we deliver the series order within 10 days. We can keep stock of your item in our warehouse and deliver it according to a schedule.
About the author
Monika Jeziorowska
Cardboard core adviser, Dominopack
She handles cardboard core sales. She works with customers to choose the core diameter, wall and crush resistance for their roll, prepares the quote and provides the parameters in writing.