Abstract A method for plastic molding an electrical assembly having a plurality of upstanding tubular members with predetermined peripheral deformations. During molding operations, the tubular members are further deformed by pressures between two facing die parts such that tolerance of the thickness of the final assembly is less than the sum of the tolerances of the individual parts. The tubular members have radially extending surfaces forming electrical contacts along one surface of the assembly. Another metal plate attached to the tubular members forms substantially the opposite surface for providing a good heat sink connection. The tubular members are spaced peripherally of the metal plate such that mold pressures are evenly applied along the plate for preventing plastic encapsulating material from seeping over the plate. Portions of the plate may extend outwardly from the tubular members with the provision of a rigidizing and apertured deformation in the base plate for preventing flexure of the plate in a mold. The apertures in the rigidizing member permit plastic flow for solidly locking the plastic encapsulating material to the base plate. Plastic encapsulating material is provided inside the tubular members by runners in other parts of the electronic assembly.
The process for fabricating a plastic encapsulated unitized electronic assembly in a mold having spaced-apart and facing die parts which are relatively movable one with respect to the other, the assembly to have large exposed opposite facing outer nonplastic surfaces contiguous with plastic encapsulating material surfaces, the improvement including in combination, forming an assemblage of electrical components to be molded comprising large oppositely facing substantially parallel metal surfaces spaced apart somewhat greater than the predetermined spacing of an ultimate molded assembly, providing deformable means in said assemblage for holding such surfaces apart and having a first compressive strength less than the compressive strength of the other of said electrical components, inserting said means between the said metal surfaces of said components, then closing said die parts such that a pressure is exerted on said means greater than said first compressive strength such that said means permits said surfaces of said assemblage to move toward each other and said die parts holding the pressure, then inserting fluid plastic encapsulating material about said assemblage with said pressure inhibiting said material from covering the opposed facing outer surfaces, and curing the plastic encapsulating material.
Claim 2
Dependent Claim
191 words
The process for fabricating a plastic encapsulated unitized electronic assembly in a mold having spaced-apart and facing die parts which are relatively movable one with respect to the other, the assembly to have large exposed opposite facing outer nonplastic surfaces contiguous with plastic encapsulating material surfaces, the improvement including in combination, forming an assemblage of electrical components to be molded comprising large oppositely facing substantially parallel metal surfaces spaced apart somewhat greater than the predetermined spacing of an ultimate molded assembly, providing deformable means in said assemblage for holding such surfaces apart and having a first compressive strength less than the compressive strength of the other of said electrical components, inserting said means between the said metal surfaces of said components, then closing said die parts such that a pressure is exerted on said means greater than said first compressive strength such that said means permits said surfaces of said assemblage to move toward each other and said die parts holding the pressure, then inserting fluid plastic encapsulating material about said assemblage with said pressure inhibiting said material from covering the opposed facing outer surfaces, and curing the plastic encapsulating material.
Claim 3
Dependent Claim
23 words
The process of claim 1 wherein said assemblage has mold runners integral therewith for permitting plastic encapsulating material to flow throughout the assembly.
Claim 4
Dependent Claim
59 words
The subject matter of claim 2 wherein said means comprises a plurality of tubular members having peripherally extending deformed segments for causing the members to collapse with the respective segments as said die parts are moved toward each other, with the total heights of the tubular members initially being greater than the spacing between the die parts when closed.
Claim 5
Dependent Claim
52 words
The subject matter of claim 3 wherein said assembly has a plurality of parallel metal rigid plates each of the parallel plates having an aperture coaxial with a tubular member and said mold runners are intermediate adjacent parallel plates to the respective apertures for facilitating plastic flow to inside the tubular members.
Claim 6
Dependent Claim
38 words
The subject matter of claim 4 wherein the mold pressure during plastic encapsulation is maintained greater than the compressible strength of the tubular member deformed segments but less than that of the tubular member outside said deformed segments.