Compression Spring Hysteresis:
The mechanical energy loss that occurs as a result of the spring ends' tendency to rotate when compressed during cyclic loading and unloading.
Spring Engineers Tip:
For compression springs, hysteresis is generally low.
Compression Spring Squareness:
Squareness, specified for springs in their unloaded position, refers to the angular deviation between the spring's axis and a line normal to the end plains.
Spring Engineers Tip:
For squared-and-ground springs, square-ness is generally specified within a 3-degree tolerance.
Compression Spring Parallelism:
Parallelism describes the relationship between a spring's ground ends as the maximum deviation in free length around the spring's circumference.
Compression Spring Deflection:
Movement of the spring ends when external loads are applied or removed.
Compression Spring Load:
Load, the force applied to a spring that causes deflection, can be determined by multiplying the spring rate by deflection. Loads can be classified according to their application requirements: static (the spring is expected to operate between specified loads a few times only), cyclic (the spring is expected to cycle between specified loads many times), or dynamic (the spring is subjected to a high rate of load application, causing periods of excessive stress).
Spring Engineers Tip:
Loads should be specified at test heights between 15 and 85 percent of the full deflection range.
Compression Spring Buckling:
Buckling occurs when a spring deforms in a non-axial direction. Once a spring buckles, it can no longer provide the intended force. Typically, buckling deformation accelerates rapidly and the spring fails.
Spring Engineers Tip:
Compression springs with free heights greater than 4 times the spring diameter are prone to buckling, and benefit from guidance (either in a tube or over a rod).