Abstract
This paper has studied optimal opening diameter of aluminum beverage bottle with screw cap for openability. As a method of evaluation, we have defined the evaluation function of openability in terms of the ratio of the minimum gripping force required for opening cap to the maximum gripping force to hold the cap. Result from the optimization of the evaluation function of 10 subjects, the optima are obtained at around 30mm. Therefore, the dimension of opening diameter that is the best for whole subjects may exist at 30mm.
