How to Choose the Right Compression Spring for Your Application
A compression spring may be a relatively small component, but choosing the wrong one can create much bigger problems. Poor performance, premature failure, inconsistent operation and unnecessary downtime can all result from a spring that isn't properly matched to its application.
At Ashfield Springs, we manufacture precision compression springs for demanding industrial applications. Whether the spring is being used in a valve, pump, hydraulic or pneumatic system, dispenser or another piece of equipment, there are several important factors to consider before specifying it.
Start with what the spring needs to do
Before looking at dimensions or materials, establish the job the spring needs to perform.
Compression springs work by resisting an applied compressive force and returning towards their original length when that force is removed. However, the required force, movement and working conditions can vary considerably between applications.
For example, a spring used inside a valve may need to deliver a consistent force across repeated cycles, while one used in a dispensing mechanism may have different requirements around travel, size and operating life.
Knowing the required load at specific working lengths is therefore an important starting point. This helps determine the spring rate and ensures the spring behaves as expected within the assembly.
Consider the available space
A spring has to work mechanically, but it also has to fit.
Key dimensions normally include the outside diameter, inside diameter, free length and wire diameter. It's also important to consider the space available when the spring is compressed.
The spring should not reach its solid length during normal operation unless the design specifically allows for it. Repeatedly over-compressing a spring can increase stress and shorten its service life.
Where space is particularly restricted, small compression springs or a custom design may be required rather than trying to make a standard component fit.
Choose the right material
Material selection isn't simply a question of strength. The environment in which the spring operates also matters.
Temperature, moisture, chemicals and the possibility of corrosion should all be considered. Stainless steel compression springs, for example, may be suitable where corrosion resistance is an important requirement.
For hydraulic springs, pneumatic valve springs and other fluid power applications, material choice may also need to account for the fluids, operating pressures and conditions the component will encounter.
Choosing the material at the specification stage can help avoid premature corrosion, loss of performance and unnecessary replacement later.
Think about working life
How often will the spring be compressed?
A spring operating occasionally has very different demands from one cycling thousands or millions of times during its working life. Where repeated cycling is expected, fatigue life becomes an important part of the specification.
The amount of compression during each cycle also matters. A spring that is regularly pushed close to its limits will experience different stresses from one operating across a smaller range.
For precision compression springs used in valves, pumps and automated equipment, repeatable performance over the intended working life can be just as important as the initial load.
Decide between stock and custom compression springs
Not every application needs a bespoke component.
Stock compression springs can be a practical choice for prototypes, maintenance requirements, product development and applications where an existing size and specification meets the design requirements. They can also make sourcing replacement components considerably simpler.
When the application has specific requirements for dimensions, load, spring rate, material or operating life, custom compression springs can provide greater control over performance.
If you're comparing stock springs with a custom solution, look beyond the initial unit cost. Availability, expected volumes, service life, consistency and the cost of changing the surrounding design should all form part of the purchasing decision.
Provide your compression spring manufacturer with the right information
The more complete the specification, the easier it is to identify or manufacture a suitable spring.
Useful information includes:
free length and working lengths
inside and outside diameter restrictions
required load or loads
available space at maximum compression
operating environment and temperature
preferred material, where specified
expected number of operating cycles
annual quantities and delivery requirements
If every detail isn't known, that doesn't necessarily prevent the conversation from starting. Drawings, samples and information about the application can all help establish the requirements.
Getting the specification right from the start
The right compression spring isn't simply the one that fits the available space. It needs to provide the required force, work reliably within its operating range and suit the environment and expected service life.
At Ashfield Springs, we work with customers requiring stock and custom compression springs, including precision components for fluid power, hydraulic, pneumatic, valve and pump applications. Our focus is on helping customers source springs that meet the practical and technical requirements of their application.
If you're specifying a new compression spring, reviewing an existing component or looking for a reliable compression spring manufacturer, contact Ashfield Springs to discuss your requirements.