01294 279396

How to design a compression spring

How to design a compression spring

Compression springs are designed to push back when a force is applied and return to their original positions when released. Their numerous applications are what make them popular. Besides electronics and stamping presses, they are also used in vibration insulation. The variations of compression springs are numerous and cater to specific needs. Several factors define the construction of compression springs. Understanding these aspects makes it easier to get the best Irvine springs for particular devices.

End Types

The ends of a compression spring are some of the factors that determine what they can do; and therefore, fundamental in the design process. A compression spring end will dictate its mounting characteristics, height, pitch and active coils. Closed and ground ends are popular because they allow springs to erect vertically. They are relatively cheaper than most because they don’t demand extra work after leaving the CNC machine. Closed and ground ends, on the other hand, are expensive for the opposite reason. The grounding of the ends takes place after CNC machining, therefore, requiring more labour and costs. The advantage that these ends have over the closed and squared alternative is that a spring with a high slenderness ratio can stand on a flat surface. The ratio proportions between the diameter and free length of a compression spring is what constitutes slenderness ratio. A high ratio is when the free length exceeds the outer diameter by four times or more. In a closed and ground end, a spring with such a ratio would buckle when stood vertically. Open ends are alternative design options, and they are not capable of a vertical stand. With all the coils open, it means that a spring has a consistent pitch at free length. Open ends are suitable for applications where a spring is needed to be weaker without increasing the height. By opening both ends, you get more coils; hence, weakening the springs but the height remains unchanged. Open and ground ends have a filed last coil, which facilitates even distribution of loads.

The Material

The functionality, quality and durability of a compression spring rely heavily on the choice of material. Material choice will also factor in the design calculations. For example, the material in use dictates tensile strength and shear modulus. Stainless steel is one of the common materials that are used in making compression springs, and it is suitable for products that are to be used in outside environments. For extremely harsh conditions, acid-proof stainless steel is most appropriate.

Piano wire is ideal for springs that are in stable surroundings such as those found indoors. This material does not offer protection against corrosion. If a piano wire spring is going to be used outside, then the material has to be pre-galvanised. A piano wire that has been through electro-galvanisation offers a shiny surface with minimal protection from rust. Compression springs can also be manufactured with speciality metals and alloys such as titanium, beryllium nickel, tantalum, and beryllium copper. Composite springs have also gained popularity recently.


The diameter of a compression spring is one of the features that determine its force. Compressing a spring increases its diameter, and this translates into the pitch. There is an inner diameter, which is the distance in the inner cavity, and then there is the outer and wire diameter. When constructing a spring, all these variables will come into play.

Spring Finish

The finishing on a spring is not only to structure its aesthetics but durability as well. Powder coating offers abrasion resistance, in addition to altering the colour of the spring. Oiled springs need lubrication to facilitate smooth compression. Shot peening finishing refers to the use of glass beads to strengthen the material. A phosphate finish provides an excellent base in case of painting. It also increases the lubrication of a spring and corrosion resistance.

A customer can pick the design of their Irvine Springs by setting parameters such as customised metals and two different ends on a spring or length, depending on their applications.

Back to top