Abstract: A novel multipart punch and system allows apertures to be formed in hydroformed members with the slug which would otherwise result being divided into two or more smaller slugs. These smaller slugs can be folded back into the hydroformed member and held captive therein or removed if desired. The multipart punch and system provides a flush surface in the hydroforming mold when the punch is in its initial position to allow easy loading and unloading of the mold and to allow additional blank to be fed into the mold during the hydroforming operation, if desired. Also, the hydraulic ram used with the multipart punch need develop less force than an equivalent prior art stepped punch.

Abstract: A novel multipart punch and system allows apertures to be formed in hydroformed members with the slug which would otherwise result being divided into two or more smaller slugs. These smaller slugs can be folded back into the hydroformed member and held captive therein or removed if desired. The multipart punch and system provides a flush surface in the hydroforming mold when the punch is in its initial position to allow easy loading and unloading of the mold and to allow additional blank to be fed into the mold during the hydroforming operation, if desired. Also, the hydraulic ram used with the multipart punch need develop less force than an equivalent prior art stepped punch.