How do you prevent 'buckling' of a multi-turn wave spring in an assembly with a high length-to-diameter ratio?

Buckling occurs when the axial load exceeds the critical buckling load $P_{cr}$. For crest-to-crest wave springs, if the free length $L_f$ exceeds $3.5$ times the mean diameter $D_m$, the spring is unstable. To prevent this, the spring must be guided by either a bore or a pilot rod. The clearance between the spring and the guide should be approximately 2-5 percent of the diameter to allow for radial expansion during compression while providing enough lateral support to maintain axial alignment. In deep-sea connectors, internal sleeves are often used to ensure the spring compresses linearly without snaking.