Work out cap torque instantly with clear inputs, formula shown and shareable results.
The industry rule of thumb sets application torque in inch-pounds at roughly half the cap diameter in millimetres, adjusted for closure type and liner. Removal torque falls to 50-70% of application torque as the liner relaxes, and that removal figure is what determines whether a consumer can open the pack.
Application torque
Torque (in-lb) = cap diameter (mm) x torque factor; N.m = in-lb x 0.113
Removal
Expected removal torque = application torque x removal ratio
Liner damage, cap or neck-finish cracking, stress cracking of the bottle over time, and packs consumers cannot open. Too low gives leaks and loss of carbonation or shelf life.
After at least 24 hours, and again after temperature cycling. Torque retention drops most in the first day, so a measurement taken at the filler tells you little about the consumer experience.