In brief
Understand application torque, removal torque, leakage, liner contact, cross-threading and how to test capped bottles and jars. Use a written requirement and compare the complete installed operating scope, not a headline specification or purchase price in isolation.
Application and removal torque are different
Application torque is set during capping; removal torque is measured later and is affected by liner compression, material relaxation, temperature and storage.
Torque does not replace seal testing
A cap can meet torque and still leak because of neck damage, contamination, liner mismatch, tilt or poor seating. Test the finished pack.
Use a controlled sampling method
Define test timing, temperature, equipment, sample sequence and handling. Compare start, middle and end of runs and different component batches.
Investigate variation at the first engagement
Cap presentation, bottle support, chuck or spindle condition, belt pressure and thread compatibility affect cross-threading and torque spread.
Information to prepare
- Cap and neck drawings
- Application method
- Test timing and temperature
- Torque instrument and method
- Liner and seal design
- Leak/storage test
- Sequential sample results
Capping Machines UK
Capping systems and torque-control routes for multiple closures.