Abstract: A plastic molding apparatus for forming three-dimensional containers from a single sheet of plastic material and each comprising side-by-side generally dish-shaped members which are hinged together which dish-shaped members have different interior configurations with respect to one another. The apparatus comprises a pair of superimposed relatively movable male and female mold members. A pair of differently configurated side-by-side mold sets are carried by the mold members. A first plurality of different inserts having different projecting configurations are provided for said first mold set. A second plurality of different inserts are provided for the second set which have surface complementary to the first projecting inserts to establish a male-female mold relationship between the first and second plurality of inserts.

Abstract: A web of thermoplastic foam material is carried through an oven by an intermittently traveling conveyor engaging or gripping opposite sides of the web. The heated web is successively advanced by the conveyor between cooled heat-absorbing forming molds, which are moved toward each other to form the foam article and away from each other to release the article. A heat trimmer melts or vaporizes the leading and trailing ends of the foam material as compressed and formed by the molds, to form the marginal leading and trailing ends of the articles to the required peripheral form determined by the leading and trailing ends or edges of the molds and to separate the leading and trailing ends of the article from the web. The cooled molds, which may be made of a heat-conducting metal, such as aluminum, absorb the heat of melting as they pressurize the material along its edges and thereby determine the leading and trailing margins of the article.

Abstract: A thermoplastic material, such as a sheet of polystyrene or polyethylene foam, is placed between a trim guide, which may be a die mold or press, and is in the form of at least two heat-conducting metal pieces, one of which is movable towards the other. The trim guide is pressure-operated to pressurize the material along the area to be trimmed. This may be an edge of a plastic sheet, the perimeter of an article produced from the material, or may be holes or slots to be cut in the material. A knife or other tool, heated to a temperature high enough to melt the material, is then moved along the trim guide. The knife vaporizes the pressurized material along the trim guide, which creates a definitive point at which melting or vaporization of the material stops. The trim guide is made from metal having high heat-conductivity, such as aluminum which has sufficient heat-conductivity to create a point at which melting, caused by the knife vaporizing the material, stops.