GB1222505A - Method of and apparatus for the production by casting of low melting point alloy press tools or dies for the manufacture of drawn sheet products - Google Patents

Abstract

1,222,505. Casting composite articles; making dies. PRESS & SHEAR MACHINERY CO. Ltd. 13 March, 1968 [15 March, 1967], No. 12065/67. Headings B3A and B3F. Matched press tools or dies for forming sheet material are made by lowering a perforated master pattern 30 mounted on a clamping plate 28 and on a vertically movable beam into a heated tank of molten low melting point (e.g. 70‹ C.) alloy 11, allowing the molten alloy to permeate through the perforations in the master pattern, and cooling the alloy by passing water from a cooler 17 over its surface. During solidification air pressure is applied at 16 to force the molten alloy from closed parts 15 into the centre of tank 11 and so prevent the formation of cavities in the casting. Preferably anchor bars 27, mounted on spacers 26 and thereby attached to the vertically movable beam are lowered with the master pattern. The molten alloy which may be melted in the tank solidifies around the anchor bars 27, to form a support for the male part of the die. After solidification ram sub-plate 25 is detached from the rest of the beam and the die assembly is mounted in a press. The die parts are separated by opening the press; the master pattern adhering to the male part of the die, from which it is subsequently removed, and the tank forming the female part of the die. The small asperities formed where the perforations of the master pattern are cleaned off. In further embodiments blank sheet holders may be formed with the dies and the whole die manufacturing procedure may take place in the press in which the dies are to be used.