The present invention relates to the molding of a bun of synthetic resin material in an open top mold having a U-cross sectional shape.
The pour, rising and curing of foam within a U-shaped open top continuous mold will normally produce a round top for the foam bun due to the friction between the rising foam and the side walls of the mold. A flat top is desired to reduce wastage, and various apparatus have been produced to produce such a flat top. One such apparatus provides an inclined pour plate between the side conveyors of the mold for the full length of the foam expansion, so that the drop rate of the pour plate relative to the sides somewhat approximates the rise rate of the foam to reduce friction between the mold side walls and the foam.
Apparatus of this type may produce a bun four to eight feet wide, three to four feet high, and at the rate of 20 feet or 500 pounds per minute. Typically, the bun will be cut to a rectangular configuration and sliced for the required thickness of matresses. Matresses, for example, are desired in various widths.