Plastic Screw Torque Specifications and Locking Design

plastic screw Torque Specifications and Locking Design

plastic screws have lower strength than metal parts. Excessive torque causes stripping, head breakage or boss melting, while insufficient torque leads to loose locking. Correct torque setting and locking design are key to plastic fastening solutions.

Recommended Torque Ranges

Torque should be set by material and size. For nylon 66 screws, roughly 0.3-0.5 N·m for M3, 0.5-0.8 N·m for M4 and 0.8-1.2 N·m for M5 are recommended; PC and peek can be higher, subject to sample testing. Use torque-controlled power tools for assembly.

Anti-Stripping Locking Design

For plastic internal threads, use metal inserts, longer engagement length or self-tapping thread designs. For frequently disassembled areas, metal insert nuts improve reuse reliability.

Avoiding Common Issues

Avoid continuous loading at high temperature causing creep and loosening. Avoid over-tightening that causes stripping. Consider temperature and humidity effects in assembly; conduct torque decay tests for critical applications.

The plastic fastener range provides torque advice and assembly support for engineers.