Improvements in or relating to tool manufacture

摘要

1,021,971. Making punches and dies. W. H. BURKHART. June 11, 1964 [June 11, 1963], No. 24372/64. Headings B3A and B3W. [Also in Division B4] A method of making a punch and die set comprises providing a strip of flexible material having a plurality of metal elements mounted on the strip in parallel relationship, each of the elements having a flat face adjacent the strip terminating in an edge extending parallel to the length of the strip, with the said edges contiguous and in the same plane, and with the elements formed to allow the strip to be bent to conform the edges to a predetermined curvature, positioning the strip and elements on a work surface with the faces conforming to the outline of the punch and die, providing a matrix to support the elements and removing the strip. The elements 12 and 121 are attached by adhesive to the flexible strip 10 which is equal in thickness to the required clearance between the punch and die. To form a punch and die set the strip is positioned on a plate 26 which has been engraved with guide lines 28 and 281, and is held in place by magnets 30. Further magnets 32 are placed at the edges of the plate and a matrix of thermosetting resin or a low melting alloy is poured into the cavities inside and outside the strip. The assembly is removed from the plate, ground on both surfaces, the inner part which forms the punch is forced out of the outer part which forms the die and both parts are bolted and dowelled to support plates. The elements 12 and 121 may be triangular in cross-section as shown in Fig. 2 (not shown), or trapezoidal and have longitudinal grooves to provide a key for the matrix. The method may be used to form an electrode for use in electrical discharge machines.