Answer
The solid height ($H_s$) of a wave spring is the height at which all waves are compressed until they are in contact. For a multi-turn spring, $H_s = n \times t$, where $n$ is the number of turns and $t$ is the material thickness. It is a critical assembly error to design a system where the spring can be compressed to or beyond its solid height. Doing so creates an 'infinite' spring rate and results in extreme localized stress at the wave peaks, often leading to immediate permanent set or plastic deformation. Assemblies should be designed with a mechanical stop that limits travel to approximately 80% of the available deflection. In automotive transmissions, spacers or shims are used to ensure the stack-up of tolerances never allows the wave spring to bottom out.
