Analyze the impact of bore roughness on the effective spring rate of an OD-piloted wave spring.

An OD-piloted wave spring expands radially as it is compressed axially. If the bore surface is rough ($>63 \mu in$ Ra), the friction between the spring's OD and the bore increases significantly. This 'frictional locking' effectively increases the observed spring rate during compression because the friction opposes the radial expansion. During decompression, the spring may 'hang up' or return slowly. For precision applications like optical lens positioning, the bore should be hard-anodized or coated with a dry-film lubricant (e.g., MoS2) to ensure the spring rate remains consistent and repeatable within $\pm 1\%$ of the design value.