The medical device industry consistently aims for compact designs to enhance portability, patient comfort, and efficiency. This often necessitates smaller components. Simon Ward, technical manager at TFC, an AFC Industries Company, emphasises the capabilities of wave springs in achieving such miniaturisation.
Springs are commonly used in a variety of medical products, such as surgical instruments, medical devices, wearable medical technology and orthopaedic equipment. They are commonly used as return springs for function buttons, where they can provide the necessary force to restore a button to its original position. Springs are also used to maintain electrical contact or compensate for assembly tolerances.
While coil springs have conventionally served these purposes, there has been a shift in preferences, andwave springs are gaining traction as an alternative. One key reason for this is their space-saving advantage, as wave springs require less than half the space of a coil spring — delivering the same spring force with a smaller operating height.
The compact design of a wave spring is particularly valuable in situations with tight space constraints. They are an excellent choice for handheld instruments, tools, and wearable devices when designers seek to create lightweight, compact and well-balanced products. For example, wave springs have been used in the design of insulin pens and in surgical and dental tools that use high-speed precision bearings.
Choosing a wave spring
When selecting a wave spring for medical use, considerations include the application's specific requirements. Crest-to-Crest™ wave springs are suitable for lower spring rates, while single-turn wave springs work well for short deflections and medium forces. Linear springs are an option for straight load-bearing systems.
However, it's critical to recognise that wave and coil springs are not interchangeable due to their different operational mechanics. Wave springs flatten under load for upward force, whereas coil springs twist, causing force deviation. Professional consultation is advised for integrating the right type of spring.
Custom options
Customisation is a significant advantage of wave springs. Specialists can tailor them in terms of turns, material, and size, considering the specific needs of the product. Materials like 302 and 316 stainless steel are popular for their ability to withstand high temperatures during cleaning and sterilisation without affecting spring properties.
Design engineers, particularly those accustomed to coil springs, may find specifying wave springs challenging. Collaborating with a specialist can be invaluable, providing expert advice on the most suitable wave spring, thereby enhancing the design and functionality of medical devices.
Need advice on choosing a wave spring for your medical application? Visit https://tfc.eu.com/products/smalley-wave-springs-retaining-rings or call 01435 866011 to speak to a member of our design team.
About the Author |
Simon Ward – Technical Manager Simon heads the TFC UK technical team and specialises in designing and developing Smalley wave springs and retaining rings. With over 20 years experience, Simon has developed bespoke parts for major clients across the globe and across numerous industry sectors. He is now widely regarded as a leading authority on Smalley products. |
