Q: How many cycles should a zipper survive in testing?
For ordinary garment zippers, a common acceptance target is 5,000 open-close cycles without functional failure, tested on a reciprocating machine at a controlled speed and with a defined pull angle. Better-quality chains often reach 10,000 cycles, and heavy-duty or luggage zippers are frequently specified at 20,000 cycles or more.
Cycle count alone is not enough. The test should record what fails: tooth wear, slider spring fatigue, tape abrasion, coating loss or a jump in pulling force. A zipper that completes 8,000 cycles but doubles its pulling force has effectively failed for the user, even if the chain still closes.
Conditions change the result. Dust, salt spray, detergent residue and low temperature all shorten life, and a slider that is pulled at an angle wears much faster than one pulled straight. Specify the test standard, the load per cycle, the environment and the failure criterion in the purchase specification. Then verify with a wash-and-wear trial on real garments, because laboratory cycles rarely reproduce the way a wearer yanks a hem.