Explain the phenomenon of 'load relaxation' during the first cycle of installation.

Upon the first compression to its minimum work height, a wave spring may experience a slight loss of free height, known as 'set' or 'relaxation'. This occurs as the material's internal residual stresses from the coiling and heat-treatment processes redistribute under load. For precision applications, it is standard practice to 'preset' the springs—compressing them to the solid height or minimum work height at the factory. This ensures that when the end-user installs the spring, the load remains stable. Calculations for work height should always be based on the 'after-set' dimensions provided by the manufacturer.