Cell Instruments Co., Ltd.
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The Flex Durability Tester, also known as the Gelbo Flex Tester, is a professional laboratory instrument designed for evaluating the flex resistance of flexible barrier materials, including plastic films, laminates, foils, and coated substrates. By simulating mechanical stress through twisting and compressive movements, this tester helps assess material integrity and durability under repeated strain, essential before conducting permeation or pin hole tests.
This testing method is critical in industries such as packaging, pharmaceuticals, food and beverage, and medical devices, where the mechanical reliability of packaging materials directly impacts product protection, shelf life, and regulatory compliance.
A Flex Durability Tester replicates real-world conditions that packaging materials endure during handling, transportation, and usage. The test simulates continuous mechanical strain on barrier films, determining their resistance to cracking and pinhole formation. This performance indicator is especially crucial for high-barrier packaging materials that must remain impermeable throughout the product lifecycle.
The test sample, typically 280 mm × 200 mm, is clamped onto mandrels. During each cycle, the film undergoes:
Twisting motion up to 440°
Horizontal compression stroke of 65 mm
Cycle speed of 45 flexes per minute
This unique twist-compression action creates multidirectional stress patterns that replicate stress during transportation or usage. Pinholes or failures are then detected by visual inspection or secondary tests like gas permeation or dye penetration.
| Parameter | Value |
|---|---|
| Flex Frequency | 45 cycles/min |
| Horizontal Stroke | 155 mm (Long) / 80 mm (Short) |
| Flexing Angle | 440° (Long Stroke) / 400° (Short Stroke) |
| Number of Stations | 4 independent testing positions |
| Sample Size | 280 mm × 200 mm |
| Control System | PLC with 7-inch touchscreen interface |
User-Friendly Interface
7-inch color touchscreen for intuitive navigation
Easy test parameter setup and real-time status monitoring
Automated Control System
PLC-controlled flex cycles for consistent performance
Programmable test modes (5 standard modes)
High Testing Efficiency
Four independent test stations allow parallel sample evaluation
Adjustable stroke length for varied material types
Compact and Durable Design
Heavy-duty frame designed for continuous industrial lab use
Built-in optional micro-printer for result output
Standards-Compliant
Fully compliant with ASTM F392 – "Standard Test Method for Flex Durability of Flexible Barrier Materials"
The Flex Durability Tester is used in various industries to evaluate the structural integrity and barrier properties of:
Flexible packaging films (PET, PE, nylon, EVOH)
Medical pouch laminates
Aluminum foil laminates
Food packaging materials
Pharmaceutical blister foils
Composite or multi-layer coatings
Before barrier testing such as oxygen transmission rate (OTR), water vapor transmission rate (WVTR), or pin hole detection, it's crucial to evaluate how the material withstands mechanical flexing. A poor flex score could mean premature barrier failure, product spoilage, or regulatory non-compliance.
Flex Durability Testing helps:
Predict material lifespan
Optimize material formulation
Reduce material failure risks
Meet international quality standards
The Flex Durability Tester strictly follows ASTM F392, a globally recognized standard for evaluating flex failure in flexible barrier materials. This ensures that the test results are reproducible, reliable, and accepted across industries for quality assurance, R&D, and compliance purposes.
Cell Instruments Co., Ltd. is a trusted manufacturer specializing in physical property testing instruments for packaging, materials, and medical industries. Our Flex Durability Tester offers advanced automation, compliance with international standards, and robust design tailored for busy QA/QC labs.
We also provide:
Customized PLC programming
Test process automation services
Global customer support
✅ Simulates real-world handling stress
✅ Accurate and repeatable testing results
✅ Supports multi-sample testing simultaneously
✅ Compliant with ASTM F392
✅ Ideal for labs in packaging, pharmaceuticals, food, medical, and academic research
Cell Instruments offers complete support including:
Installation guidance
Testing protocol consultation
Annual calibration services
Spare parts availability
Operator training and certification