What are the best spring materials for pharmaceutical products?

A pharmaceutical spring faces stricter manufacturing and compliance requirements than most other spring applications. They need to be durable and high-performing for medical devices to be functional in the long-term.  At the same time, they need to be clean to meet the strict standards of national and international medical regulations. 

Selecting the most optimal material for a spring is crucial. The correct choice will provide the necessary properties to both ensure ease of assembly, design scalability and manufacturing repeatability. In this article, we discuss the types of pharmaceutical springs, the factors that affect their operability, and the importance of material choice. 

Pharmaceutical spring types and their requirements

Compression springs

Compression springs are helically coiled wire that store and release mechanical energy when compressed and decompressed. They are crucial for repeat use drug administration applications like inhalers and other respiratory devices. Because of their repeated use, compression springs need to have high fatigue strength to maintain full functionality for long periods without the risk of failure.

Torsion springs

Torsion springs are designed to resist compressive forces and store mechanical energy to use when needed. They are suitable for single-use pharmaceutical devices due to their precise expelled force. Because of this precision, torsion springs need to have a high elastic limit to manage a static load for a long period without losing any mechanical energy.

Extension springs

Extension springs are compressed when no force is applied, and are used to connect two components together by resisting the pulling force between them. These are used in a number of wearables and pharmaceutical devices like medical pliers. Due to their contact to skin, extension springs need to showcase high cleanability to avoid the risk of particulates collecting on the surface and risking illness to patients.

Factors that affect the performance and lifespan of pharmaceutical springs

The functional requirements of each type of pharmaceutical spring can overlap, but so do the number of factors that can affect their performance, lifespan, and as a result, their ability to meet required standards.

• Wear - Repeat-use pharmaceutical devices in particular are susceptible to wear from high amplitude stresses. This gradually builds spring fatigue from fretting, and will eventually result in device failure if not addressed.
  
• Corrosion - Pharmaceutical devices face a range of environmental factors such as different temperatures and humidity. These environments can lead to the gradual build of corrosion on the spring’s substrate, leading to a loss of tension, static strength and/or functionality.
  
• Cleanability - Particulate contamination is a significant challenge for pharmaceutical devices due to the health risks associated. As a result, springs and other components need to showcase surface characteristics that enable thorough cleanability and reduce the risk of particulate contamination and concentrations.
  

Why material choice is important for pharmaceutical springs

Depending on the type of spring, type of device and specific application, different materials will provide the necessary resistances/protections to maintain functionality and ensure compliance with specific standards.

• Steel - A commonly used material in a range of pharmaceutical applications. Exhibits good corrosion resistance, strength, formability, weldability and low cost. Stainless steel alloys also showcase good cleanability and resistance to wear, making it a suitable material choice for springs in a wide range of pharmaceutical designs.
  
• Titanium - An extremely strong yet extremely light metal that is resistant to wear and can hold a static load for extended periods. It can also be sterilised repeatedly without compromising surface quality to enable the extended use of designs. Suitable for springs in both single-use and repeat-use applications.
  
• Nickel and copper alloys - Nickel presents exceptional corrosion resistance to be used for springs that face aggressive environments. Copper springs also provide good corrosion resistance and are naturally anti-bacterial. Both spring materials are suitable for corrosive and bacterial environments.
  

Integrate the perfect spring material choice for your pharmaceutical design

Pharmaceutical designs face one of the most strict environments in terms of standards and regulation. Each of their components needs to showcase high performance and precision, which is often determined by their material and specific application.

At Advanex Medical, we create a range of springs from a range of materials including steels, copper and nickel alloys, Titanium, Elgilloy, Hastelloy, Kanthal and others. We also have a number of finishing and post-cleaning options available in-house, ranging from electroplating, organic zinc coatings and much more.

To find out more about our products or to get additional pricing information, contact a member of our team today.