Method for forming recyclable pour tool

• US 4,860,815 A
• Filed: 08/17/1987
• Issued: 08/29/1989
• Est. Priority Date: 08/17/1987
• Status: Expired due to Fees

• Current Assignee: Davidson Textron Inc. (Textron Inc)
• Original Assignee: Davidson Textron Inc. (Textron Inc)
• Inventors: Parker, Kent, Clavette, Norman, Batchelder, Bruce
• Primary Examiner(s): Silbaugh, Jan H.
• Assistant Examiner(s): Kuhns, Allan R.
• Application Number:
  US07/085,796
• Time in Patent Office: 743 Days
• Field of Search: 264/227, 264/46.6, 264/225, 164/45, 164/46, 164/47
• US Class Current: 164/47
• CPC Class Codes: B22C 7/00 Patterns; Manufacture thereof so far as not provided for in other classes

Abstract

A method and apparatus for manufacturing a composite article by use of a mold core and a cavity block and wherein a skin and insert are placed in the mold cavity and foam precursors are poured into the mold cavity to complete the article includes a process in which a series of part replicas are formed and used to cast thermally stable liners that are carried by the mold core and mold cavity. The thermally stable liners have low melt temperatures and can be reused and recast following wear during the molding process. The liners are made from material which has low shrinkage and expansion rates to define a mold assembly that will produce repeatable parts.

Claims

1. A method for manufacturing liners with outer surfaces for mounting on a production mold apparatus to define a mold cavity, the metal liners having inner surfaces which exactly conform to the exterior dimensions of a composite plastic article having a preformed skin adapted to be supported on the inner surface of one of the metal liners and a preformed load bearing insert adapted to be supported on the inner surface of the other of the metal liners and wherein a layer of foam material is located between the performed skin and the preformed load bearing insert to be bonded thereto comprising the steps of:

dimensionally shaping a single piece pattern which has outer dimensions thereon corresponding to those of the composite plastic article including the foamed preformed skin and preformed load bearing insert;

providing metal casting mold means having an interior space greater than the dimensions of the single piece pattern;

supporting the single piece pattern in the interior space of the metal casting mold means to provide a space for filling with metal to form liners conformed to the outer surface of the single piece pattern and conformed to the metal casting mold means;

casting aluminum filled methyl methacrylate into the last mentioned space for filling said space to form liners conformed to the single piece pattern and conformed to the metal casting mold means;

providing a mold assembly having liner support surfaces thereon;

removing the cast aluminum filled methyl methacrylate liners from the metal casting mold means and placing them on the liner support surfaces of the mold assembly;

shimming the aluminum filled methyl methacrylate liners with respect to the liner support surfaces of the mold assembly to form a space within the mold assembly which corresponds to the outer dimensions of a foamed preformed load bearing insert and preformed skin of a composite plastic part;

pouring material into the space to form a second single piece pattern which is conformed to the shape of the interior surfaces of the aluminum filled methyl methacrylate liners; and

supporting the second single piece pattern on the metal casting mold to form a space for forming a second set of liners that have outer surfaces thereon which are supportable on a mold assembly to form an interior space when supported on the mold assembly which corresponds to the outer dimension of the foamed preformed load bearing insert and preformed skin and to form the support surfaces on the mold assembly for the performed load bearing insert and the preformed skin.

2. A method for manufacturing recyclable liners with outer surfaces for mounting on a production mold apparatus to define a mold cavity, the metal liners having inner surfaces which exactly conform to the exterior dimensions of a composite plastic article having a preformed skin adapted to be supported on the inner surface of one of the metal liners and a preformed load bearing insert adapted to be supported on the inner surface of the other of the metal liners and wherein a layer of foam material is located between the preformed skin and the preformed load bearing insert to be bonded thereto comprising the steps of:

dimensionally shaping a single piece pattern which has outer dimensions thereon corresponding to those of the composite plastic article including the foamed preformed skin and preformed load bearing insert;

providing metal casting mold means having an interior space greater than the dimensions of the single piece pattern;

supporting the single piece pattern in the interior space of the metal casting mold means to provide a space for filling with metal to form liners conformed to the outer surface of the single piece pattern and conformed to the metal casting mold means;

melting a metallic material at a temperature in the range of 300 degrees F. and pouring the melt into the last mentioned spaced for filling the space to form liners conformed to the single piece pattern and conformed to the metal casting mold means;

providing a mold assembly having liner support surfaces thereon;

removing the metal liners from the metal casting mold means and placing them on the liner support surfaces of the mold assembly;

shimming the metal liners with respect to the liner support surfaces of the mold assembly to form a space within the mold assembly which corresponds to the outer dimensions of a foamed preformed load bearing insert and preformed skin of a composite plastic part;

pouring material into the space to form a second single piece pattern which is conformed to the shape of the interior surfaces of the metal liners; and

supporting the second single piece pattern on the metal casting mold to form a space for forming a second set of liners that have outer surfaces thereon which are supportable on a mold assembly to form an interior space when supported on the mold assembly which corresponds to the outer dimension of the foamed preformed load bearing insert and preformed skin and to form the support surfaces on the mold assembly for the preformed load bearing insert and the preformed skin.

4. In the method of claim 2, casting each of the liners from a bismuth-based alloy material.

3. A method for manufacturing recyclable liners with outer surfaces for mounting on a production mold apparatus to define a mold cavity, the metal liners having inner surfaces which exactly conform to the exterior dimensions of a composite plastic article having a preformed skin adapted to be supported on the inner surface of one of the metal liners and a preformed load bearing insert adapted to be supported on the inner surface of the other of the metal liners and wherein a layer of foam material is located between the preformed skin and the preformed load bearing insert to be bonded thereto comprising the steps of:

dimensionally shaping a single piece pattern which has outer dimensions thereon corresponding to those of the composite plastic article including the foamed preformed skin and preformed load bearing insert;

providing metal casting mold means having an interior space greater than the dimensions of the single piece pattern;

supporting the single piece pattern in the interior space of the metal casting mold means to provide a space for filling with metal to form liners conformed to the outer surface of the single piece pattern and conformed to the metal casting mold means;

melting bismuth based metallic material at a temperature in the range of 300 degrees F. and pouring the melt into the last mentioned spaced for filling the space to form liners conformed to the single piece pattern and conformed to the metal casting mold means;

providing a mold assembly having liner support surfaces thereon;

removing the cast bismuth based metallic liners from the metal casting and mold means and placing them on the liner support surfaces of the mold assembly;

shimming the bismuth based metallic liners with respect to the liner support surfaces of the mold assembly to form a space within the mold assembly which corresponds to the outer dimensions of a foamed preformed load bearing insert and preformed skin of a composite plastic part;

pouring material into the space to form a second single piece pattern which is conformed to the shape of the interior surfaces of the bismuth based metal liners; and

supporting the second single piece pattern on the metal casting mold to form a space for forming a second set of liners that have outer surfaces thereon which are supportable on a mold assembly to form an interior space when supported on the mold assembly which corresponds to the outer dimension of the foamed preformed load bearing insert and preformed skin and to form the support surfaces on the mold assembly for the preformed load bearing insert and the preformed skin.

5. In the method of claim 3, the bismuth based material having a contraction rate during said cooling of approximately 0.0005 in. per in.