Compression springs are open-coiled helical springs that exert a load or force when compressed. A Compression spring gets shorter as the load is applied.
The wire size, number of coils and diameter (ID-inside or OD-outside), all determine the strength of the spring.
The spring ends can be left open ended, closed, tapered or ground and affects the spring force. In many designs, the spring requires a L/H (left hand) or R/H (right hand) helix.
Predicting spring life is not an exact science and must be carefully considered in all stages of design with your spring manufacturer. However, the life expectancy of a spring can be extended by careful design and selection of material.
One important factor overlooked during the design process is the spring index. A spring index is the relationship between a spring's mean diameter and wire diameter. Generally the index should be above 3 and less than 20. Ideal index: 7 - 13
Mean diameter divided by wire diameter = Spring Index
