GB732118A - Method of producing resin bonded moulds and cores, moulds and cores so formed, methods of casting using these, and castings made thereby - Google Patents

Abstract

732,118. Moulds and cores ; moulding processes; making cores. FORD MOTOR CO., Ltd. Nov. 20, 1952 [April 10, 1952], No. 9281/52. Class 83 (1). A sectional mould-or core-unit of a sand resin mixture has opposite faces accurately formed to desired dimensions by heating in contact with patterns. A metal box having a sprue-pin a, Fig. 2, runner b, and patterns c is heated to about 400‹ F.., a cold frame e is fitted and sand-resin mixture poured into the box. Frame e is then replaced by a heated pattern plate h, Fig. 3, which is pressed into the mixture, e.g. hydraulically or pneumatically. The patterns and box are coated with a parting agent before filling. The finished unit is cured at about 550‹ F. for approximately 60 seconds, e.g. in an oven or by electrical heating elements incorporated in the box and plate, and then stripped from the box, e.g. by spring-loaded ejector pins incorporated in the box. In use, a number of units are superimposed, having a common sprue and casting recesses and runners at the junction of adjacent units, sockets j and lugs k being provided for locating purposes. The box may be on a conveyer passed beneath a hopper, the gate of which is opened automatically by a lever system to discharge the mixture in the box, any excess being removed by a spring-loaded scraper. In a modification, the plate h is provided with holes through which sand-resin mixture is extruded when the plate is pressed into the box.