Device for punching green sheets

A device for punching sheet-like substrates, comprising:

• a receiving device having a substantially flat receiving face for a ceramic substrate, and having a punched hole formed in the flat surface;
• a die disposed above the punched hole, said die having a shaft, and an operative portion that extends through and is guided in a constant diameter stripper opening disposed in a stripper above the punched hole and extending to an outer surface of the stripper facing the receiving face, said operative portion including a first part that is guided by a surface defining the stripper opening and has a diameter that is less than the diameter of the shaft and greater than the diameter of the punched hole, and a second cylindrical punching part that is disposed at a lower end of the first part, and has a diameter that is less than the diameter of the first part and slightly less than the diameter of the punched hole and a length that is less than the length of the stripper opening so that a portion of the first part is always guided within the stripper opening, and with the diameter of the shaft being a multiple of the diameter of the first part of the operative portion;
• a drive mechanism connected in driving fashion to the die to move the die linearly by a defined stroke and in the process move the punching part into and out of the punched hole;
• and
• a die guide through which the shaft extends and which guides the die shaft.

A tool for punching sheet-like substrates, comprising:

• a lower tool part having a substantially flat receiving face for a substrate, and having a punched hole formed in the flat surface;
• an upper tool part
• a die having a shaft, and a graduated operative portion including a first part having a diameter that is less than the diameter of the shaft and greater than the diameter of the punched hole, and a second cylindrical punching part disposed at a lower end of the first part and having a diameter that is less than the diameter of the first part and slightly less than the diameter of the punched hole, and with the diameter of the shaft being a multiple of the diameter of the first part of the operative portion;
• a linear die guide disposed in the upper tool part above the punched hole;
• a stripper bush mounted on a surface of the upper tool part facing the lower tool part and having a constant diameter stripper opening disposed above the punched hole and extending to an outer surface of the stripper bush facing the receiving surface;
• said die being disposed above the punched hole and mounted in the upper tool part for linear movement toward and away from the lower tool part, with the shaft of the die being disposed in and guided by the linear die guide, the second punching part of the operative portion having a length that is less than the length of the stripper bush, and the first part of the operative portion of the die always extending into the stripper opening and being guided by a wall of the stripper bush defining the stripper opening;
• and
• a drive mechanism connected in driving fashion to the die to move the die linearly by a defined stroke and in the process move the punching part into and out of the punched hole.