Products + Tools

By Nick Carter, head of innovation, Gottlieb Binder GmbH & Co KG

Self Engaging Reclosable Fasteners (SERFs) represent a highly adaptable technology in fastening systems offering flexibility, durability, and reusability, with the fasteners designed to provide secure attachment and ready detachment of surfaces – making them ideal for a wide range of applications, from manufacturing to everyday use.

SERFs are designed to securely attach two surfaces, with the possibility to remove or adjust them as needed. The core structure of a SERF consists of ‘mushroom-like’ engagement elements that are typically formed into a tape. These tapes are cut to size and attached to two surfaces to be mounted together. When these two tapes, with hundreds to thousands of engagement elements each are pressed together, they interlock, creating a secure bond with a characteristic ‘snap’ feel and sound. To disengage the fastener, the user only needs to apply enough force to separate the engagement elements, which is usually between 1.5 to 4 times the force used to engage the fastener. This simple mechanism enables reusability, making SERFs an eco-friendly and cost-effective alternative to traditional fastening methods.

One of the unique benefits of SERFs is their ability to adapt to misalignments in the surfaces being fastened. They can accommodate varying degrees of twist, tilt, and shift, without requiring new mounting points or changes to the fastener itself. Furthermore, SERFs can be used for ‘blind’ attachment – fastening in areas with limited access – a valuable function to have in industries such as transportation, electronics and construction.

SERFs are especially useful when a mounted surface is to undergo periodic replacement or repair, such as wall panelling, headliners and trim pieces, without the potential issues of fixed position mechanical fasteners or adhesives.

The evolution of SERFs

The concept of SERFs first gained commercial traction in the mid-1960s. Early versions of these fasteners were made using an extrusion process, where plastic resins were shaped into films with stem-like projections. The ends of these stems were then heated to form caps, creating the characteristic mushroom shape. Over time, technological advancements and a deeper understanding of material behaviour led to significant improvements in SERF performance.

Modern SERFs now incorporate woven materials, which offer multiple key benefits:

• Customisation: The yarn placement in woven materials can be tailored to meet specific performance needs, allowing for better control over the fastener’s strength and durability.
• Enhanced functionality: The woven structure increases the overall effectiveness of the fastener, improving its engagement and disengagement properties under a broad range of environmental stresses (heat, cold, wet).
• Alignment tolerance: The stems in the engagement elements are designed to bend, making the fasteners even more forgiving of misalignments, reducing installation complexity.
• Resistance to external forces: Modern SERFs are engineered to withstand greater shear and shock loads, ensuring they stay secure in challenging conditions.

These advancements have made modern SERFs far more durable and dependable than their predecessors, providing a superior fastening solution in various applications.

Not all SERFs are created equal

When selecting a SERF for a specific application, it’s important to consider the performance characteristics of the fastener. It is crucial to assess the levels and duration of force the fastener will be subjected to in the application, as this will influence the choice of fastener type and size. It’s also essential to note that SERFs are distinct from other types of reclosable fasteners, such as hook and loop or contact fasteners:

• SERFs: These fasteners are made from a single tape, clip, or profile that locks onto itself, creating a strong and durable connection.
• Hook and loop fasteners: These systems consist of two separate components – one with hooks and the other with loops – that interlock when pressed together.

SERFs offer superior closure durability and resistance to accidental opening, which makes them ideal for applications where security is critical. Additionally, SERFs are a reliable alternative to spring clips, screws, and bolts, particularly in blind fastening applications. They also help reduce the impact of manufacturing variances, improving assembly accuracy and resulting in higher ‘first time right’ assembly rates while minimising the need for time-consuming adjustments.

Why choose Binder for your SERF needs?

For high performance SERF solutions, Binder offers its Duotec^® product line. Duotec^® woven fasteners are designed with precision to provide secure, long-term fastening options. These fasteners are crafted using carefully selected materials and use round filaments to ensure predictable disengagement behaviour and ease of engagement.

Duotec^® fasteners are resistant to shear forces, minimising the risk of creep under load and maintaining a secure hold. They are also highly adaptable to alignment changes, vibration, and environmental impacts, ensuring reliability in diverse conditions.

With Duotec^® fasteners, Binder offers a cost-effective and simple solution for a wide range of applications, providing flexibility, durability and reusability for industries that require secure and adjustable fastening systems.

Conclusion

Self Engaging Reclosable Fasteners (SERFs) represent a significant alternative in fastening technology. Their unique design enables secure, reusable connections with the ability to adapt to misalignments. By choosing the right SERF system, such as Binder’s Duotec® fasteners, businesses can benefit from increased efficiency, reduced waste and improved overall performance.