This study investigates the influence of frictional properties between the spring wire and coiling tools on the deformation behavior during the coiling process with coiling pin system, using dynamic explicit finite element analysis with ANSYS LS-DYNA. The analysis focused on varying the coefficients of dynamic friction between the wire and four key tools: the wire guide, first coiling pin, second coiling pin, and pitch tool. Results revealed that the average coil diameter, stress distribution, and compressive axial force during forming were significantly affected by frictional conditions, particularly those at the second coiling pin. A reduction in the friction coefficient at the second coiling pin led to increased coil diameters and decreased stress and axial force. These findings indicate that friction at the second pin predominantly governs coil shaping and significantly impacts spring dimensions. Furthermore, deteriorated sliding properties due to inadequate lubrication may cause dimensional variation or even failure during forming. This analysis emphasizes the critical role of wire-tool friction management in ensuring spring quality and consistency.
Sudo et al. (Wed,) studied this question.