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ISO 7854

ISO 7854 is an internationally recognized test method used to evaluate the resistance of plastic films and flexible packaging materials to repeated flexing and mechanical stress. Flexible films often experience bending, folding, twisting, and handling forces during manufacturing, transportation, and end use. Without sufficient durability, these repeated stresses may create pinholes, cracks, or loss of barrier performance.

The purpose of ISO 7854 is to measure the ability of flexible materials to withstand repeated deformation under controlled laboratory conditions. The test provides valuable information about flex durability, helping manufacturers select suitable materials and improve packaging reliability.

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ISO 7854 - Gelbo Flex Test Method

The gelbo test method is one of the most common approaches used in ISO 7854 testing. It evaluates how a film sample responds to repeated twisting and compression movements. During the test, a specially designed Gelbo Flex Tester applies controlled rotational and horizontal movements to create repeated mechanical deformation.

The Gelbo Flex Test is particularly important for materials where barrier integrity is critical, including:

  • Flexible food packaging films
  • Pharmaceutical packaging materials
  • Medical barrier films
  • Aluminum foil laminates
  • Plastic multilayer structures
  • Coated and laminated films

The primary purpose of this evaluation is to determine flex durability, which refers to the material’s ability to maintain physical and functional properties after repeated flexing.

A material with good flex durability can better withstand transportation vibration, package handling, and consumer use without developing defects.

ISO 7854 - Gelbo Flex Test Method

The gelbo test method is one of the most common approaches used in ISO 7854 testing. It evaluates how a film sample responds to repeated twisting and compression movements. During the test, a specially designed Gelbo Flex Tester applies controlled rotational and horizontal movements to create repeated mechanical deformation.

The Gelbo Flex Test is particularly important for materials where barrier integrity is critical, including:

  • Flexible food packaging films
  • Pharmaceutical packaging materials
  • Medical barrier films
  • Aluminum foil laminates
  • Plastic multilayer structures
  • Coated and laminated films

The primary purpose of this evaluation is to determine flex durability, which refers to the material’s ability to maintain physical and functional properties after repeated flexing.

A material with good flex durability can better withstand transportation vibration, package handling, and consumer use without developing defects.

ISO 7854 Method C
Crumple/Flex Method for Film Testing

Among the ISO 7854 procedures, the Method C Crumple/Flex Method is commonly applied for evaluating flexible packaging materials that require high resistance to repeated deformation.

This method creates mechanical stress through a combination of twisting and crumpling actions. Compared with simple bending tests, the crumple/flex approach better represents the complex deformation conditions experienced by flexible packaging during transportation and handling.

The test is especially useful for materials such as:

  • Barrier films used in food packaging
  • Flexible pouches
  • Vacuum packaging films
  • Laminated structures containing aluminum foil
  • High-performance protective films

By analyzing damage after repeated flex cycles, manufacturers can determine whether a material maintains sufficient barrier performance throughout its expected service life.

Principle of ISO 7854 Gelbo Flex Test Method

The ISO 7854 test principle is based on applying repeated mechanical deformation to a flexible film specimen and evaluating the resulting damage.

In the Gelbo Flex Test process, a rectangular film specimen is mounted between two clamps. One clamp remains fixed while the other performs a combined twisting and compression movement. This movement creates repeated folding and stretching similar to the stresses experienced by flexible packaging during actual use.

The test process generally includes:

1. Sample Preparation
A film specimen is cut into the required dimensions according to the selected ISO 7854 procedure.

2. Sample Installation
The specimen is mounted securely on the Gelbo Flex Tester to ensure consistent deformation during testing.

3. Flexing Operation
The instrument applies repeated twisting and compression cycles at a controlled frequency.

4. Defect Evaluation
After a defined number of cycles, the sample is inspected for pinholes, cracks, or other damage.

5. Performance Analysis
The results indicate the material’s resistance to repeated mechanical stress and its overall flex durability.

ISO 7854 Gelbo Flex Test for Film Flex Durability
Gelbo Flex Tester

Three/Four Ststions

Cell Instruments Gelbo Flex Tester for ISO 7854 Testing

o perform ISO 7854 Gelbo Flex Test accurately, Cell Instruments provides the GFT-01 and GFT-02 Gelbo Flex Testers, which are designed to evaluate the flex durability of flexible films, laminates, and barrier packaging materials under repeated twisting and compression conditions.

Both models support controlled flexing movements required for ISO 7854 testing, including a standard flex frequency of 45 cycles/minute and adjustable flex angles of 440° or 400° according to different test requirements. The instruments provide stable mechanical motion and repeatable results, helping laboratories evaluate material resistance against cracking, pinhole formation, and barrier failure caused by repeated deformation.

The main difference between the two models is the testing capacity:

  • GFT-01 Gelbo Flex Tester is suitable for routine quality control and laboratory testing, featuring 4 testing stations 
  • GFT-02 Gelbo Flex Tester with 3 testing stations, making it suitable for applications requiring stronger mechanical stress evaluation or testing of more rigid multilayer materials.

Both models can be applied to plastic films, aluminum foil laminates, medical packaging materials, and other flexible structures where flex durability is a critical performance requirement.

Importance of Flex Durability Testing for Flexible Packaging

Flexible packaging materials must maintain strength and barrier properties throughout production, distribution, and usage. Even small defects caused by repeated mechanical stress may lead to:

  • Moisture or oxygen barrier failure
  • Product contamination risks
  • Reduced shelf life
  • Leakage problems
  • Increased packaging waste

The ISO 7854 test provides manufacturers with reliable data for material development and quality control.

Flex durability testing helps:

Material Selection
Compare different films, coatings, and laminate structures.

Quality Control
Monitor production consistency between different batches.

Research and Development
Optimize film formulations and layer structures.

Packaging Reliability Evaluation
Confirm that packaging can withstand practical handling conditions.

ISO7854 - Gelbo Flex Test Method

The ISO 7854 Gelbo Flex Test is widely used across industries where flexible material durability is essential.

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Frequently Asked Questions (FAQ)

Q1: What does ISO 7854 measure?

A: ISO 7854 measures the resistance of flexible films and packaging materials to repeated flexing and mechanical deformation.

A: The Gelbo Flex Test evaluates whether flexible materials can withstand repeated twisting and compression without developing defects such as pinholes or cracks.

A: Common materials include plastic films, laminated films, aluminum foil composites, barrier packaging materials, and flexible packaging structures.

 

A: Good flex durability helps packaging maintain barrier performance and prevents failures caused by handling, transportation, and repeated mechanical stress.

 

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For inquiries or to request a demo, reach out to Cell Instruments

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