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Mechanical Punches Capable of Punching Holes Less than Three Mils in Diameter

IP.com Disclosure Number: IPCOM000107480D
Original Publication Date: 1992-Feb-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 1 page(s) / 28K

Publishing Venue

IBM

Related People

Aoude, F: AUTHOR [+4]

Abstract

Disclosed is a new design for mechanical punches, that are capable of punching less than 3 mil holes in green sheets of 4 to 10 mils in thickness. The reinforced structural design and the adapted die bushing will increase the strength of the punch to a level higher than that of the breaking point.

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Mechanical Punches Capable of Punching Holes Less than Three Mils in Diameter

      Disclosed is a new design for mechanical punches, that are
capable of punching less than 3 mil holes in green sheets of 4 to 10
mils in thickness.  The reinforced structural design and the adapted
die bushing will increase the strength of the punch to a level higher
than that of the breaking point.

      Standard punches are normally built where the effective
punching area and the guided travel distance of the punch are both of
the same diameter.  By increasing the diameter of the punch at the
portion that guides travel distance, the strength of the punch will
increase following the model:
                                   Pcr   N2EI
                                          L2
where Pcr is critical buckling strength, E is the elastic modulus, I
is moment of inertia, I=f d4/64 d is the diameter, L is the length of
the punch.

      By knowing the material properties and the geometry of the
punch, the Pcr could be estimated.

      Disclosed anonymously.