Different Types of Compression Springs: Which is Right for Your Application?

First, we have to answer the question, ‘What is a compression spring?’ Understanding what this invaluable component is, how it works, and what it’s used for will help you decide if you need compression springs. We’ve put together this guide to help you do just that, covering:

• What Are Compression Springs and Why Are They Important?
• Types of Compression Springs: How Do They Differ?
• Characteristics of Compression Springs: Materials and Performance
• Selecting the Right Compression Spring: Tips and Considerations
• Applications and Industries: Where Are Compression Springs Used?

What Are Compression Springs and Why Are They Important?

Compression springs, sometimes called coil springs, are mechanical devices designed to store potential energy when compressed and release that energy when the compression force is removed. Springs are typically made from materials such as steel or stainless steel and are formed into a helical shape. The spring's coils are closely spaced, allowing them to compress when an external force is applied and expand when the force is removed.

These compression springs are important for several reasons: 

• Store and release energy: When the compression force is released, so is the energy. This property allows them to absorb shock or impact, cushion vibrations, and maintain consistent forces in various mechanisms.
• Provide resistance: Compression springs offer resistance against compressive forces, opposing the applied load and maintaining a specific pressure or tension. They help maintain proper functioning of mechanical systems by exerting a specific force or pressure as required.
• Absorb and distribute forces: spring compression absorbs and distributes forces generated during movement or operation. It helps prevent damage to components by absorbing shocks and vibrations, increasing the lifespan of the equipment.
• Control motion: Compression coil springs are used in applications where controlled and predictable motion is required. They provide precise force and motion control in various mechanisms, such as automotive suspensions, valves, and industrial equipment.

Types of Compression Springs: How Do They Differ?

Compression springs have different end types to suit various installation and functional requirements of different applications. The choice of end type can affect how the spring interacts with its surroundings and how it performs in a specific mechanism. The choice of compression spring end types depends on the specific requirements of the application, including the available space, the method of installation, the desired load distribution, and the type of mating components. Different end types of coil compression springs provide distinct benefits and characteristics:

Closed End:

• Both ends of the compression spring are closed, meaning the last coil at each end is tightly wound against the adjacent coil.
• The closed ends provide a stable and flat surface for the spring to rest against the supporting components, ensuring proper alignment and load distribution.
• Often used when the spring needs to be seated firmly in a specific location.

Open End:

• In contrast to closed ends, both ends of the compression spring are left open, without any tight winding at the ends.
• Open ends are suitable for applications where the spring needs to be mounted on shafts, pins, or other cylindrical objects.
• The open ends allow for a more flexible installation, and are commonly used when the spring must slide or rotate on its mounting points.

Ground End:

• A ground end refers to a closed end that has been ground flat and smooth.
• Ground ends provide a good surface for load distribution and reduce the risk of the spring "popping out" under certain conditions.
• Ground ends are often used when the spring needs to be in contact with flat surfaces or mating components.

Double-Closed Ends:

• Both ends of the spring are closed and ground flat.
• Offers excellent stability and load distribution, making it suitable for applications where precise alignment and consistent performance are critical.
• Double closed ends are commonly used in high-precision equipment and mechanisms.

Spring compression types

Below are examples of compression springs with open, closed and double-closed ends.

Characteristics of Compression Springs: Materials and Performance

Stainless-steel compression springs are common. Other materials that compression springs are typically made from are carbon steel and high tensile-strength chromium alloy steels. 

You can learn more in our guide, What are the differences between carbon steel and stainless steel?

Stainless-steel compression springs

• Corrosion resistance: Stainless steel is well-known for its exceptional corrosion resistance, making it ideal for applications where the spring will be exposed to moisture, chemicals, or harsh environments. In comparison to regular carbon steel springs, stainless-steel springs are less prone to rusting or corrosion, ensuring a longer lifespan and better performance in challenging conditions.
• Good strength: Stainless steel has excellent mechanical properties, providing good tensile strength and durability. This makes stainless-steel springs suitable for applications that require load-bearing capabilities and resistance to deformation or fatigue.
• Temperature resistance: Stainless-steel compression springs can maintain their mechanical properties and resist deformation at both high and low temperatures. This characteristic makes them well-suited for applications in extreme temperature environments.
• Non-magnetic: Some stainless steel grades, such as austenitic stainless steels, are non-magnetic, making them suitable for use in electronic and electromagnetic applications where magnetic interference needs to be minimised.

You can learn more in our Guide to Stainless Steel Grades. 

Disadvantage of stainless-steel compression springs

Depending on the grade, stainless-steel compression springs may have slightly reduced tensile strength compared to carbon steel springs. 

Carbon-steel compression springs

• High strength and durability: Carbon-steel compression springs are known for their excellent tensile strength and resistance to deformation. This high strength allows carbon steel springs to withstand heavy loads and provide reliable performance in demanding applications.
• Heat-treatment capability: Carbon steel compression springs can be easily heat-treated to enhance their properties further. Heat treatment processes like quenching and tempering can increase the hardness, strength, and durability of the springs.
• Magnetic properties: Carbon steel springs are generally magnetic, which can be advantageous in certain applications, such as those involving magnetic fields or electromagnetic systems.
• Resilience and fatigue resistance: Good resilience and fatigue resistance, making them suitable for cyclic or repetitive loading scenarios.

Disadvantage of carbon steel compression springs

Carbon steel has lower corrosion resistance compared to stainless-steel compression springs. They’re more susceptible to rust and oxidation, which can limit their use in harsh environments. 

High-tensile strength chromium alloy steels

• High strength and durability: Chromium alloy steels exhibit high-tensile strength and excellent resistance to deformation and fatigue. Compression springs made of these materials withstand heavy loads and provide reliable and consistent performance over a prolonged period.
• Improved fatigue resistance: Chromium alloy steels are engineered for enhanced fatigue resistance, making them ideal for applications involving repetitive loading cycles, such as automotive suspensions and heavy machinery.
• Hardenability: Can be heat-treated to achieve varying hardness levels and mechanical properties. This versatility allows manufacturers to tailor the spring's characteristics to meet specific performance requirements.
• High-temperature stability: These steels maintain their strength and mechanical properties at elevated temperatures, making them suitable for exposure to heat or high-temperature environments.

Disadvantages of high-tensile strength chromium alloy steels

Some chromium alloy steels can provide moderate corrosion resistance, especially when compared to regular carbon steels. If using the compression spring in a corrosive environment, opt for stainless steel. 

Selecting the Right Compression Spring: Tips and Considerations

Selecting the right compression spring for a specific application is crucial to ensure optimal performance and longevity. For help with your selection process, follow this advice:
    
1. Spring Rate

Calculate the required spring rate (force per unit of deflection) based on the load and the desired deflection or travel of the spring. The spring rate influences how the spring will behave under various loads.

The formula to calculate the spring rate is as follows:
Spring Rate (k) = Loading Force (F) / Deflection (x)

Where:
k = Spring Rate (force per unit of deflection) in units of force per unit distance (e.g., N/mm, lbf/in, etc.)
F = Load or Force applied to the spring in units of force (e.g., Newtons, pounds, etc.)
x = Deflection or travel of the spring in units of distance (e.g., millimetres, inches, etc.)

Follow these steps for calculating the required spring rate:

• Determine the Load (F): Identify the load or force that the spring needs to support or resist. This could be the weight of an object, the force applied by a mechanism, or any other force acting on the spring.
• Measure the Deflection (x): Determine the desired deflection or travel of the spring. This is the amount by which the spring will compress or extend under the applied load.
• Divide the load (F) by the deflection (x) to calculate the spring rate (k). Ensure that the units for load and deflection are consistent, for example use Newtons and millimetres or pounds and inches).

2. Spring Material

Choose the appropriate material based on factors such as the application environment, temperature range, and application. For instance, if repeated loading cycles are involved, you should choose a material with high fatigue resistance. 

3. End Types

Determine the suitable end types for the application. End configurations should be based on how the compression spring will be mounted and interact with surrounding components.

4. Space limitations

How much space is available? You may need to consider compression springs by size –  what will fit within the designated area while giving you the required deflection and load capacity. Note, small compression springs are available. 

Depending on your application, torsion springs might be the more appropriate choice. To learn more, check out our guide, Torsion Springs, Explained. 
 

Applications and Industries: Where Are Compression Springs Used?

The versatility, reliability, and ability to control forces make compression springs an indispensable component. Some common applications and industries where compression springs are used include:

Download free CADs and try before you buy

Free CADs are available for most solutions, which you can download. You can also request free samples to ensure the product you’ve chosen is exactly what you need. 

If you’re not quite sure which solution will work best for your application, our experts are always happy to advise you.

Whatever your requirements, you can depend on fast despatch. Request your free samples or download free CADs now.

Questions?

Email us at sales@essentracomponents.co.uk or speak to one of our experts for further information on the ideal solution for your application 0345 528 0474.