Method for manufacturing a mold for producing molded parts of large size and of a composite material
First Claim
1. A process for producing a mold to make molded pieces with large dimensions, in particular pieces having a large length, and made of composite material, comprising forming a thick, rigid sheet metal mold cavity wall having an inner mold surface with an impression shape for pieces to be molded, and an exterior mold surface, the wall having high thermal conductivity, applying a plurality of electrical resistance heating elements on one of said inner and exterior mold surfaces of said wall and in direct contact with said wall, covering said wall plus heating elements with a layer which is at least partly made of metal that gives the layer thermal conductivity, covering said wall plus heating elements, at said exterior mold surface of said wall, with a layer of non-rigid synthetic resin foam having low density and being thermally insulating, and mounting said wall with its heating elements and layers to a mold frame.
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Accused Products
Abstract
A molding cavity wall (10) is made in a plurality of parts of a cheap material having a high thermal conductivity, for example a thin metal sheet (10), at least one heating device (11) is applied on the wall in direct thermal exchange relation to the external surface of the wall (10), and a thermal insulator constituted by a foam (12) of highly rigid resin is applied to the wall (10) in uniform pressure transmitting relation to said wall.
57 Citations
12 Claims
- 1. A process for producing a mold to make molded pieces with large dimensions, in particular pieces having a large length, and made of composite material, comprising forming a thick, rigid sheet metal mold cavity wall having an inner mold surface with an impression shape for pieces to be molded, and an exterior mold surface, the wall having high thermal conductivity, applying a plurality of electrical resistance heating elements on one of said inner and exterior mold surfaces of said wall and in direct contact with said wall, covering said wall plus heating elements with a layer which is at least partly made of metal that gives the layer thermal conductivity, covering said wall plus heating elements, at said exterior mold surface of said wall, with a layer of non-rigid synthetic resin foam having low density and being thermally insulating, and mounting said wall with its heating elements and layers to a mold frame.
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5. A process for producing a mold intended for forming molded parts with large dimensions, especially parts of great length, made of a composite material and particularly of reinforced resin, polymerized by the application of heat and pressure, comprising:
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making an impression molding plate of thick and rigid sheet metal with high thermal conductivity, with an internal molding surface substantially in the shape of a part to be molded and an external surface; applying a number of heating elements in the form of blankets including electrical resistors to the external surface of this impression molding plate and in direct thermal contact with this plate; covering the external surface of the impression molding plate equipped with the aforesaid heating elements, with an insulating coating of non-rigid synthetic resin foam, of low density and low thermal conductivity; and enclosing the molding plate with its heating elements and its insulating coating in a structure which is rigid relative to a uniform transmission of pressure to the structure. - View Dependent Claims (6, 7, 8)
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9. A process for producing a mold intended for the production of molded parts of large dimensions, made of composite material and especially of reinforced resin, polymerized by the application of heat and pressure, comprising the following steps in succession:
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making an impression molding plate with thick and rigid sheet metal with high thermal conductivity, having an internal molding surface essentially in the shape of the parts to be molded and an external surface; shaping a recess of substantially constant thickness in the aforesaid internal surface; placing in this recess a thin tape having substantially the thickness of the recess and composed of heating elements forming electrical resistance and in direct thermal contact with the wall of the aforesaid recess; covering the external surface of the impression molding plate with an insulating layer of non-rigid synthetic resin foam of low density and low thermal conductivity; and enclosing this impression molding plate with its heating elements and its insulating layer in a structure which is rigid relative to the uniform transmission of pressure. - View Dependent Claims (10, 11, 12)
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Specification