Abstract
The speed effect on the high-speed punching in a commercially aluminum sheet is investigated by an impact test machine using the compressed air. The projectile, which is considered as a punch, is accelerated at the air pressure and collides with the specimen fixed in the die. The hole is formed by penetration of the projectile. The shearing force is measured using strain gages mounted on the side surface of the die. From experimental results, it was found that the shearing force was decreased when the impact velocity exceed a critical velocity. It was demonstrated that sheared surfaces changed from the brittle fractured surface to the ductile fractured surface with the increase in impact velocity.
