Answer
At high rotational speeds, centrifugal forces can cause a wave spring to expand radially and shift off-center, leading to dynamic imbalance and vibration. To prevent this, the assembly should incorporate a 'pilot'—either a step in the shaft or a recess in the housing—that captures the spring's $ID$ or $OD$ respectively. In Crest-to-Crest springs, the centrifugal expansion is more pronounced at the middle turns. For speeds exceeding $3600$ RPM, engineers should calculate the 'lift-off' speed where the centrifugal force $F_c = m r \omega^2$ exceeds the radial stiffness of the spring. If lift-off occurs, the spring may rub against the bore, causing heat and potentially failing the assembly. Specialized 'Nested' springs are often more stable at high speeds due to their tighter radial footprint.
