Background

A critical property of flexible barrier materials is their ability to withstand repetitive strain, known as flex durability or Gelboflex resistance. Strong flex crack resistance is essential as it lowers the risk of package perforation during distribution, safeguarding package integrity.

Application

The flex durability tester, also known as Gelboflex, assesses the ability of materials like films, composites, and coating films to withstand repetitive strain. It quantifies flex failure by detecting pinholes that may develop in the sample structure. Excellent flex crack resistance is vital as it minimizes the risk of packaging developing holes during distribution, ensuring the package remains intact throughout its journey. This is crucial for preserving the integrity of the contents within.

Standards

ASTM F392 "Flex durability of flexible barrier materials".

Sampling and motion

In the flex tester, a sample measuring 200 by 280 mm is affixed to the mandrels. The flexing process involves a combination of twisting and horizontal compression, repeatedly subjecting the film to both actions. Specifically, the setup initiates a twisting motion spanning 440 degrees within the first 90 mm of the stroke, followed by a linear horizontal motion of 65 mm. The entire cycle occurs at a speed of 45 cycles per minute.

Users have the option to select from five preprogrammed test conditions.

Mode A– Full flex for 1 hour (2,700 cycles),
Mode B– Full flex for 20 minutes (900 cycles),
Mode C– Full flex for 6 minutes (270 cycles),
Mode D– Full flex for 20 cycles,
Mode E– Partial flex for 20 cycles.

Technical Features

The system features PLC control with an intuitive HMI touch screen interface. It offers five standard test modes and includes four test stations. Users can quickly switch between long and short stroke modes. Test conditions A, B, C, D, and E are selectable, and the system is equipped with a microprinter for convenient data output.

Main Parameters  

Flex Frequency 45 /minute
Flex Angle 440° (90 mm) or 400° (80 mm)
Capacity 2.5 N.m
Horizontal Stroke 155 mm or 80 mm
Stations 4
Sample Size 280 mm x 200 mm
Power 110~220V