Roll length (running meters)
For practical reasons, the net material weight (i.e. minus the winding core) on the roll is used to determine the roll length, taking into account the determined mass per unit area and the web width.
For shorter roll lengths (max. 50 running meters), it is also possible to unwind the film and measure the length oof the web with a calibrated measuring tape
. Note: In the field of soft plastic films (e.g. made of polyethylene), the roll running lengths can be affected by elastic forces added during production if the measurement is carried out by a measuring device running on the material web within the production machine. The usual running length tolerance of ± 2%, for example, must therefore be increased by up to 10% for functional reasons or taken into account accordingly in the unwinding tension.
In short — AI-generated
This test determines the length of a roll of flexible packaging material, such as plastic film, by calculating the net material weight and taking into account the mass per unit area and web width. For shorter rolls, the length can also be measured directly with a calibrated measuring tape. The test is performed according to the GKV Blatt I-IV standards for polyethylene films.
The resulting roll length value is used to verify that the packaging material meets the required specifications and to ensure accurate production and processing. The value is also important for calculating the amount of material needed for a specific application and for quality control purposes. The roll length tolerance, typically ± 2%, may need to be adjusted due to elastic forces in the material, affecting the unwinding tension and overall production process.
Text is AI-generated; based on test method data curated and verified by Innoform.
Standard Tests
tesile test laminated films/ orientated films DIN EN ISO 527
Specific Norm: GKV Blatt I- IV
For practical reasons, measurements in the laboratory can only be carried out on short rolls with a maximum length of approx. ≤ 50 linear meters. Comparative measurements can be carried out on rolls of any length by running counters on the film web in the production environment.
Gravimetric determination based on the net roll weight
Specific Norm: GKV Blatt I- IV
This is a reference method that is suitable for checking the running length of any roll size. The prerequisite is a calibrated balance with the appropriate measuring range and precise knowledge of the weight of the core, the web width and the mass per unit area of the wound material. If this data is not known, the values can also be determined using suitable measuring methods.
Comparative measurement of mechanical and gravimetric method
Specific Norm: GKV Blatt I- IV
The results of the mechanical length measurement are compared here with the reference method with the aforementioned limitations and conditions for both methods.
