Fundamental Mistakes in Spring Design

Categories: Design and Innovation, Engineering, News, Springs, Springtelligence, Wireform|1015 words|5.1 min read|By |Published On: February 11th, 2019|

Springs are very often overlooked in the design process of new products. It is no exaggeration to say that they are a key functional component in most mechanical devices and that, without a properly designed spring, the products functionality and lifespan is adversely affected.

The spring is often considered a small and inexpensive part of a much larger article, therefore the designer will recognise that there is a requirement for a spring, but may leave the specification of the spring until last.

This results in compromise. All too often the designer may not have left enough space to fit a spring that enables the product to function as it should. Spring manufacturers would then try to manufacture springs at the boundaries of what is mechanically possible because the spring element of the design has not been a priority. This is likely to increase costs both in the design project and the application as a whole.

Three key areas of spring design that should be considered early in the spring design process are:

  1. Forces

What force or load is the spring required to exert? The more accurately this information can be supplied to the spring designer the better the outcome of the early prototypes. This in turn makes trial and error through several prototype runs less likely, resulting in a less expensive overall design process. It is important that the spring manufacturer is given accurate information as it is not likely they will be an expert in the specific device or field into which the spring will eventually work. The spring designer generally requires 1 or 2 loads at lengths or a required spring rate. From this information, they can start to put together a spring specification.

  1. Environment

It is important to understand the environment so that the correct material and surface finish is selected. Springs are useful in all sectors across all environments from satellites in space to an engine and from a gas pipeline to a pen. The various different environments that a spring may find itself in will have different corrosive effects on the spring material. The operating temperatures are also important. Through a combination of material selection (there are literally hundreds of different materials springs can be made from) and/or secondary protective surface finishes most environments can be catered for.

The more exotic (corrosion resistant, suitable for high temperatures etc.) the more expensive the spring is to manufacture. This is a combination of a higher cost for raw material and more complexities in production such as long and specific heat treatment requirements. Consequently, it can add unnecessary costs to use an exotic material when it is not required. Spring manufacturers can provide advice on when an exotic material might be required. Secondary finishes are usually a sub-contract process that again adds cost and lead time to the production process and so again it is important to understand if this is required or not.

  1. Spatial Constraints

Due to the fact that a spring is often one of the last components considered in the design of a larger product, compromises are often needed on either the performance of the spring or overall product as there is not enough space for the optimal spring design. This can result in either highly stressed springs that may fulfil the force requirements but to a limited lifespan, or the product not working to its optimal capabilities as a strong enough spring cannot fit into the space allowed. Another compromise is that other parts of the finished product may have to be moved or adjusted to allow the correct size of spring to fit. Consequently, not having the understanding of what is possible in a certain space can be detrimental to the finished product as a whole.

Other considerations are the dynamic movement of a spring under load and that manufacturing tolerances for springs are larger than for other machined parts. For example, a compression spring will expand when it is put under load and the further it is compressed the more the diameter will expand. If this expansion and the maximum allowable tolerance have not been considered the spring may clash with the surrounding components. This will greatly affect and reduce the performance and lifespan of the spring.

These are just some of the fundamental considerations that need to be made early on in the design process. They all impact each other: the force required generally dictates the size of the spring; the environment has a bearing on the material selection; each type of material has a different set of mechanical properties that will also affect the size of the spring. Once the size of the spring is known it is essential to ensure that enough space has been given to allow the spring to function unhindered by mating components.

Can the force required be provided in the space allowable, by commercially available materials and manufacturing processes?

Choosing Spring Manufacturers 

The specialist field of spring engineering touches all areas of mechanical engineering so choose a spring manufacturer that has extensive and proven design engineering knowledge, experience and capabilities and can help guide and advise you during the design phase of your project.

Combining over 128 years’ experience and expertise with leading-edge technology, JB Springs can assist in the design, testing, and production of spring and wireform solutions to solve the most difficult of problems.

We can cite a number of notable innovation success stories across a range of industries which have been the result of our dedicated design team working directly with our customers, or on their behalf. We offer complete product development support that not only checks and advises on the feasibility of a concept but helps prove the design.

By utilising the very latest technologies and tools we can create working prototypes that aid in the testing and development of the product. This can then reduce the cost and time required to take the spring to production.

Through our Springtelligence education and training programme we are constantly seeking to expand our knowledge in spring engineering, and learn and adopt the latest and most efficient manufacturing processes and systems.