Answer
The solid height $H_s$ of a nested wave spring is calculated as $H_s = n \cdot t$, where $n$ is the number of turns and $t$ is the material thickness. However, this is a theoretical minimum. In reality, $H_s$ is influenced by the 'form error' of each wave. The effective solid height is usually $H_{s,eff} = n \cdot t + (n-1) \cdot \delta$, where $\delta$ is the deviation from perfectly flat coiling. When designing the housing, one must account for the maximum material condition (MMC) of the spring. If the gap between the spring and the housing floor is less than $H_{s,eff}$, the spring will 'bottom out' prematurely. This causes a sudden, infinite increase in the spring rate, often leading to catastrophic failure of the mating components or the spring itself due to extreme localized stress.
