Understanding SERF performance measurements

The performance of self-engaging reclosable fasteners (SERFs) is typically measured in two related but distinct units. Understanding the difference between these units is essential to ensure the fastener meets the requirements of your application.

Units of measurement

Force per area (N/cm²)

• Definition: This unit, Newtons per square centimetre, measures the force required to engage or disengage the fastener per unit of surface area. It can be calculated by dividing the total force data (N) by the total engagement area of the fastener.
• Conversion:  1 N/cm² ≈ 1.5 lbs.-force/in².
• Purpose: It is used in technical data sheets and catalogues to provide ‘normalised’ performance data. This makes it easier to compare fasteners based on their design and engineering specifications, independent of size.

Total force (N)

• Definition: This is the total force required to engage or disengage the complete fastener. It can be calculated by multiplying the normalised force data (N/cm²) by the total engagement area of the fastener.
• Conversion: 1 Newton ≈ 0.22 lbs.-force.
• Purpose: It provides an indicator of real-world performance and is critical for evaluating fasteners from a production and maintenance perspective.

Why both units matter

• Normalised force (N/cm²): is important for defining design and engineering requirements and for comparing two different fasteners.
• Total force (N): reflects actual performance in use, providing an indication of the effort needed to operate the fastener in practical applications. It can be used to define a SERF based on the weight and related loads that an object might have or create.

Binder’s Duotec^® advantage

Binder’s Duotec^® product family offers market-leading variants with exceptional performance relative to their size. This makes them an ideal choice for applications where strength and reliability are critical.