Official Answer
Answer
Most wave springs are manufactured using an 'edge-winding' process (No-Tooling-Charge method), where flat wire is coiled on edge. This process preserves the grain flow of the material along the longitudinal axis of the wire, which is ideal for spring performance. In contrast, punching springs from flat sheet results in transverse grain orientation and significant material waste. Edge-winding allows for the use of pre-tempered or cold-reduced wire, which possesses higher tensile strength and better fatigue life. The metallurgical integrity of the edge-wound spring is superior because the rolling process induces beneficial compressive residual stresses on the outer edges of the wire.
