Punching device and punch therefor

摘要

A perforating press, e.g. for perforating green sheets in the production of ceramic substrates, has a pattern of thin needles (21) held in a press block with the pointed ends passing through the sheets and into a set of socket holes. The top ends of the needles have waisted sections (24) onto which are secured shrink fit sleeves (22) to provide a thrust surface to drive the thin needles. The waisted profile can be prepared in a variety of processes and with a variety of profiles. The sleeve can be metal or plastic and can be fitted by a cold or hot process. The needles are replaceable when worn.