Compression springs are very common and used in a broad range of applications. Characterized by an open-coil helical form, compression springs offer resistance to axially applied force. In essence, when force is applied on a compression spring, it pushes back. This occurs because the spring is designed to return to its original resting state when pressure is applied.
The compression spring appears to be simplistic, but there are multiple factors to consider in a compression spring design. When designing a compression spring, consider the following:
Answering these questions provide the necessary framework for your compression spring design. To fill in this framework, compression spring designers determine the various characteristics necessary to meet the spring’s designed objective. These characteristics include:
This page will discuss the challenges of compression spring design and how to address them.
Compression springs have a simplistic appearance, so it is common to overlook the fact that specific design intentions have been carefully implemented. In reality, compression springs require careful calculations and the combination of a wide range of engineered elements to fulfill the purpose of their design.
These calculations relate to spring force or spring rate, spring index, and various dimensional tolerances. Careful consideration of the length of wire, the overall outside diameter (OD), inside diameter (ID) of the coil, and the stress tolerances it can handle are all critical to ensure the end product will function as intended.
Various environmental factors may affect the performance of a compression spring. These factors dictate the materials used, because certain materials perform better in some extreme environments. However, using these materials in standard operating environments adds higher, unnecessary costs to the spring’s design. Material selection also relates to how they will hold up under spring formation or construction. Environmental factors for concern may include:
Compressions springs are typically manufactured by feeding wire stock into an auto-coiler. Individual springs or small production runs can be coiled using a lathe, but this practice has gone out of use due to safety concerns for the operator. Auto-coilers are highly versatile and can typically be adjusted to alter the major factors of the spring, such as length, number of coils, or coil tension.
After coiling, compression springs are often heat treated to improve their physical properties. This process makes the wire material brittle and harder to bend, so it’s important not to heat-treat before coiling.
The design elements of the spring’s design ultimately contribute to its performance within the installed application and are worthy of close consideration and testing before full-scale production. Some of these elements include:
Various environmental factors and manufacturing processes influence material selection. Each wire type can contribute specific properties, which impact performance, manufacturing, and longevity of the spring. The following wire materials are used in compression springs:
Wire shape contributes various performance advantages and disadvantages. There are two wire shapes used in compression spring design: round and square.
The configuration of the ends of the spring contributes to its performance as well. There are four different end configurations considered in compression spring design, including:
Each shape provides certain benefits. The four most common shapes used in spring design include:
The primary engineering elements within a spring design include:
Compression springs appear in a wide range of applications throughout most industries. Some of the most common industries include:
At Southern Spring & Stamping, Inc., we have more than 60 years of experience in the manufacture of compression springs. Our team uses advanced Computer Numerical Control (CNC) machinery to form wire into compression springs, providing superior precision and high repeatability.
Our material selection allows our clients to make the most cost-effective material choices for their operation. Our facilities are ISO 9001:2015 certified and we adhere to a comprehensive list of industry standards, including:
Compliance with these standards provides documented proof of our commitment to quality, productivity, reduced costs, and low defect rates, and increased customer satisfaction. We offer prototyping and design support and can handle production runs of all sizes.
Our end-to-end services cover the entire spring manufacturing process, including: