A compression spring is an open-coil helical spring that offers resistance to a compressive force applied axially. Compression springs are commonly coiled as a constant diameter cylinder, below are several types of compression springs including:
convex compression springs
These are used individually or in conjunction with each other. Round wire is predominant in compression springs because it is readily available and adaptable to standard coiler tooling.
Compression springs should be stress relieved to remove residual forming stresses produced by the coiling operation. Depending on design and space limitations, compression springs may be categorized according to stress level.