Circuit board having cast circuitry and method of manufacture

Claim 2

A circuit member (11) of the type comprising a dielectric support member (10) and cast metal circuit traces (24, 24'), characterized in that said support member (10) has on at least one surface (12, 12') thereof a pattern of discrete recesses (14., 14') which coincide with circuit paths (24, 24'), said circuit'member (11) having cast conductive material in said recesses (14, 14').

Claim 3

A circuit member (11) as in claim 1, characterized in that said dielectric support member (10) has two opposed, planar, parallel surfaces and holes (16,18) which communicate between said surfaces (12, 12'), each said hole (16, 18) communicating with a recess (14, 14') in at least one of said surfaces (12, 12'), and said cast conductive material lies in said holes (16, 18) and forms continua of metal between the surfaces (12, 12').

Claim 4

A circuit member (11) as in claim 2, characterized in that some of said continua of metal between said surfaces (12, 12') define lead-receiving holes (26) between said surfaces, each said lead-receiving hole (26) being concentric with and of smaller diameter than the hole (16) within which the respective continuum of metal lies.

Claim 5

A circuit member as in claim 1, characterized in that said conductive metal lying in said recesses is flush with said surface.

Claim 6

A circuit board (11) of the type comprising a molded dielectric support member (10) and cast metal circuit traces (24, 24'), characterized in that said support member (10) has two opposed, generally flat, parallel surfaces (12, 12'), at least one of said surfaces (12, 12') having a pattern of discrete recesses (14, 14') therein, said recesses (14, 14') coinciding with circuit paths (24, 24'), said support member having a plurality of holes (16, 18) therethrough between said surfaces (12, 12'), each said hole (16, 18) communicating with a recess (14, 14') in at least one of said surfaces (12, 12'), said circuit board (11) having cast conductive metal in said recesses (14, 14') and holes (16, 18), said metal generally filling said recesses (14, 14') and being generally flush with said surfaces (12, 12'), said metal in said holes forming discrete continua of metal between the surfaces (12, 12').

Claim 7

A circuit board (11) of the type comprising a molded dielectric support member (10) and cast metal circuit traces (24, 24'), characterized in that said support member (10) has two opposed, generally flat, parallel surfaces (12, 12'), at least one of said surfaces (12, 12') having a pattern of discrete recesses (14, 14') therein, said recesses (14, 14') coinciding with circuit paths (24, 24'), said support member having a plurality of holes (16, 18) therethrough between said surfaces (12, 12'), each said hole (16, 18) communicating with a recess (14, 14') in at least one of said surfaces (12, 12'), said circuit board (11) having cast conductive metal in said recesses (14, 14') and holes (16, 18), said metal generally filling said recesses (14, 14') and being generally flush with said surfaces (12, 12'), said metal in said holes forming discrete continua of metal between the surfaces (12, 12').

Claim 8

A circuit board (11) as in claim 5 characterized in that some of said continua of metal between said surfaces (12, 12'1 define lead-receiving holes (26) between said surfaces (12, 12'), each said lead-receiving hole (26) being concentric with and of smaller diameter than the hole (16) within which the respective continuum (32) of metal lies.

Claim 9

A circuit board (11) as in claim 6 characterized in that each hole (16) having a continuum of metal therein having a lead-receiving hole (26) therein is countersunk at each surface (12, 12'), said continuum of metal in each hole (16) being in the shape of a spool (32) having flanges (30) in the countersink (28) at each surface, whereby said flanges (30) serve to anchor said cast conductive metal in said dielectric support member.

Claim 10

A circuit board (11) of the type comprising a molded dielectric support member (10) having two-opposed, generally flat, parallel surfaces (12, 12') thereon and cast metal circuit traces (24, 24') characterized in that said support member is manufactured by the steps of molding at least one of said surfaces (12, 12') with a pattern of discrete recesses (14, 14') therein, each recess (14, 14') coinciding with a circuit path (24, 24'), said circuit board (11) having a plurality of holes (16, 18) therethrough between said surfaces (12, 12'), each said hole (16, 18) communicating with a recess (14, 14') in at least one of said surfaces, inserting a core pin (94) into each of some of said holes (16, 18), each said core pin (94) being smaller than its respective hole (16), die casting conductive metal into said recesses (14, 14'), said holes (16, 18) providing paths whereby said metal may flow between said surfaces, and removing said core pins (94) from respective holes (16) after metal is cast thereby leaving lead-receiving holes (26) through the conductive metal in the board (11).

Claim 11

A circuit board (11) of the type comprising a molded dielectric support member (10) having two-opposed, generally flat, parallel surfaces (12, 12') thereon and cast metal circuit traces (24, 24') characterized in that said support member is manufactured by the steps of molding at least one of said surfaces (12, 12') with a pattern of discrete recesses (14, 14') therein, each recess (14, 14') coinciding with a circuit path (24, 24'), said circuit board (11) having a plurality of holes (16, 18) therethrough between said surfaces (12, 12'), each said hole (16, 18) communicating with a recess (14, 14') in at least one of said surfaces, inserting a core pin (94) into each of some of said holes (16, 18), each said core pin (94) being smaller than its respective hole (16), die casting conductive metal into said recesses (14, 14'), said holes (16, 18) providing paths whereby said metal may flow between said surfaces, and removing said core pins (94) from respective holes (16) after metal is cast thereby leaving lead-receiving holes (26) through the conductive metal in the board (11).

Claim 14

A method as in claim 9 characterized in that said metal is die cast.

Claim 15

Apparatus (34) for die casting metal to form circuit traces (24, 24') carried by a generally flat substrate (10) having opposed parallel surfaces (12, 12'), said apparatus (34) being of the type comprising a gate plate (54) having a generally flat casting surface (57) which is brought into one surface (12) of said substrate (10) and gates (70) therethrough which communicate between said casting surface (57) and a molten metal reservoir (68), said apparatus (34) further comprising means for introducing molten metal into said reservoir, said apparatus (34) further comprising a pin plate (72) having a generally flat casting surface (73) which is brought into contact with the other surface of the substrate (10), said pin plate (72) having pin holes (96) therethrough and core pins (94) closely thereon, said pin holes (96) being arranged to communicate with an array of through holes (16) in said substrate (10) which intersect both surfaces (12, 12') thereof, characterized in that said pin plate (72) is resiliently mounted to a platen (90) having said core pins (94) fixedly mounted thereto, whereby, said substrate (10) is sandwiched between said casting surface (57) of said gate plate (54) and said casting surface (73) of said pin plate (72), said core pins (94) emerging from said pin holes (96) and entering said through holes (16) as said casting surface (73) of said pin plate (72) bears against said other surface (12') of said substrate (10), said molten metal is introduced into said reservoir (68) and flows via said gates into said through holes (16), said metal crystallizes and said platen (90) is withdrawn, drawing said core pins (94) into said pin holes (96) and leaving metal defining lead-receiving holes (26) in said through holes (16) in said substrate.

Claim 16

Apparatus (34) for die casting metal to form circuit traces (24, 24') carried by a generally flat substrate (10) having opposed parallel surfaces (12, 12'), said apparatus (34) being of the type comprising a gate plate (54) having a generally flat casting surface (57) which is brought into one surface (12) of said substrate (10) and gates (70) therethrough which communicate between said casting surface (57) and a molten metal reservoir (68), said apparatus (34) further comprising means for introducing molten metal into said reservoir, said apparatus (34) further comprising a pin plate (72) having a generally flat casting surface (73) which is brought into contact with the other surface of the substrate (10), said pin plate (72) having pin holes (96) therethrough and core pins (94) closely thereon, said pin holes (96) being arranged to communicate with an array of through holes (16) in said substrate (10) which intersect both surfaces (12, 12') thereof, characterized in that said pin plate (72) is resiliently mounted to a platen (90) having said core pins (94) fixedly mounted thereto, whereby, said substrate (10) is sandwiched between said casting surface (57) of said gate plate (54) and said casting surface (73) of said pin plate (72), said core pins (94) emerging from said pin holes (96) and entering said through holes (16) as said casting surface (73) of said pin plate (72) bears against said other surface (12') of said substrate (10), said molten metal is introduced into said reservoir (68) and flows via said gates into said through holes (16), said metal crystallizes and said platen (90) is withdrawn, drawing said core pins (94) into said pin holes (96) and leaving metal defining lead-receiving holes (26) in said through holes (16) in said substrate.