Measuring sticking ability of adhesive sensitive to pressure - involves using electromagnetic force to retrieve ball rolled into adhesive

摘要

The stricking ability of adhesive sensitive to pressure is determined by dispensing adhesive on a support and allowing a ball to roll onto it from a chute. A vertical force is then applied to return the ball to starting position. A ball (20, 21) of magnetic material is released electromagnetically from a chute (16) onto adhesive (18) on a support (17). Release of the ball is sensed by photoelectric cell (24). The electromagnetic force is switched on to attract the ball from the adhesive in two phases. Fir the initial phase the force balances ball weight. In the second phase force is applied to unstick the ball to return it to the retaining core (16). The photocell senses this return.