Compression molding a charge using vacuum

Claim 1

A method of making an automotive part having a surface area of at least about two square feet and providing the part with a smooth surface by compression molding a charge containing a curable resin, said method comprising: a. opening a mold having an upper die and a lower die with opposing molding surfaces that cooperate to define a mold cavity having a shape corresponding to the desired shape of the part; b. placing the charge on the molding surface of one of the dies so that the charge covers 40%-80% of the surface area of the molding surface; c. moving the dies toward each other to a partially closed condition where the mold cavity is essentially defined but the other die remains spaced from the charge; d. evacuating the mold cavity; e. closing the mold so that the dies compress the charge to cause it to fill the mold cavity; f. allowing the resin to cure; and g. opening the dies and removing the part without applying a coating to the part while in the mold.

Claim 2

A method of making an automotive part having a surface area of at least about two square feet and providing the part with a smooth surface by compression molding a charge containing a curable resin, said method comprising: a. opening a mold having an upper die and a lower die with opposing molding surfaces that cooperate to define a mold cavity having a shape corresponding to the desired shape of the part; b. placing the charge on the molding surface of one of the dies so that the charge covers 40%-80% of the surface area of the molding surface; c. moving the dies toward each other to a partially closed condition where the mold cavity is essentially defined but the other die remains spaced from the charge; d. evacuating the mold cavity; e. closing the mold so that the dies compress the charge to cause it to fill the mold cavity; f. allowing the resin to cure; and g. opening the dies and removing the part without applying a coating to the part while in the mold.

Claim 5

A method of making an automotive exterior body panel characterized by a generally flat surface having a surface area exceeding two square feet which is desired to have a smooth finish, said method comprising: a. opening a mold having an upper die and lower die with opposing molding surfaces cooperating to define a mold cavity having a shape corresponding to the desired shape of the panel; b. placing a charge of sheet molding compound (SMC) on the molding surface of one of the dies so that the charge covers 40%-80% of the surface area of the molding surface; c. moving the dies toward each other to a partially closed condition where the mold cavity is essentially defined but the other die remains spaced from the charge; d. evacuating the mold cavity to at least 10 inches of mercury absolute within a period of less than 10 seconds; e. closing the mold so that the dies compress the charge causing it to fill the mold cavity; f. heating the charge to 140-160 degrees Centigrade under a pressure between the dies of 500-1500 psi; and g. opening the dies and removing the panel without applying a coating to the part while in the mold.

Claim 6

A method of making an automotive exterior body panel characterized by a generally flat surface having a surface area exceeding two square feet which is desired to have a smooth finish, said method comprising: a. opening a mold having an upper die and lower die with opposing molding surfaces cooperating to define a mold cavity having a shape corresponding to the desired shape of the panel; b. placing a charge of sheet molding compound (SMC) on the molding surface of one of the dies so that the charge covers 40%-80% of the surface area of the molding surface; c. moving the dies toward each other to a partially closed condition where the mold cavity is essentially defined but the other die remains spaced from the charge; d. evacuating the mold cavity to at least 10 inches of mercury absolute within a period of less than 10 seconds; e. closing the mold so that the dies compress the charge causing it to fill the mold cavity; f. heating the charge to 140-160 degrees Centigrade under a pressure between the dies of 500-1500 psi; and g. opening the dies and removing the panel without applying a coating to the part while in the mold.