Custom fasteners made stronger

Jon Lawson

Ben Moskalik presents a look into the edgewinding process 

If you have never heard of edgewound fasteners or are not familiar with the edge winding process,you might want to keep reading. This little known but very interesting process is not even a topic included in the five million+ articles on Wikipedia.

Over the past few decades, innovations in fastener manufacturing processes and technologies have helped shape this industry and the end products they are a crucial component in. Edgewinding is one of those processes that has actually been around for many years and is typically used in manufacturing retaining rings and wave springs.

Edgewinding involves precision forming operations that coil pre-tempered flat wire on edge to create a near-perfect circle. The circular-grain metallurgy produced by edgewinding (top image) manufactures fasteners with strength and stability far superior to that of conventional stamped retaining rings and springs.

Developing the machinery and operational team it takes to successfully implement this process is no easy feat. Most retaining rings and wave springs are stamped; produced simply by stamping the part through the metal grain (as shown in bottom image).

There are three key benefits that make edgewound retaining rings and wave springs a better solution than stamped parts.

The first benefit is limited material waste. Edgewound rings and springs can be coiled to specification in various diameters and numbers of turns – layers or coils – so there’s no material waste. This allows for the economical production of stainless steel and other exotic alloys.

Superior strength is another benefit. Edge- coiled fasteners make for rings and springs with 

metal crystallites having long axes going with the circumference. This is in contrast with stamping parts from flat sheet metal, which makes the grains going straight through the part – a less resilient material.

Quicker prototypes is the third key benefit. Edgewinding, also known as the No-Tooling-Cost process gives manufacturing flexibility that allows them to make fine adjustments to a custom part quickly and efficiently. This allows customers to have production- grade samples for prototype testing faster than they thought possible.

Edgewound fasteners allow engineers to design components with endless possibilities in dimension, all with a quick turn-around time and superior quality.

For more information, visit www.engineerlive.com/design

Ben Moskalikgy is senior R&D engineer at Smalley

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