System and method for electroplating of hole surfaces

Abstract

An electroplating method for plating internal surfaces of holes in metal products uses a needle anode associated with an XYZ or multi-direction positioning device to position the needle such that an insertion portion of the needle anode is centered over a hole and inserted to a predetermined depth in the hole, with a discharge end located a predetermined distance from the inner end of the hole. Plating solution is supplied to the needle anode and flows continuously during plating from the discharge end of the needle, through a gap between the needle anode and inner surface of the hole, and out of the open end of the hole into a drain. In one example, the metal object is a terminal of an electrical connector and the hole is a solder cup at a terminal end of the connector.

We claim: 
     
         1 . A method of electroplating an interior surface of a hole in a workpiece, comprising:
 supporting a workpiece having at least one hole to be plated beneath a plating system including a tubular electrode of conductive material having at least an insertion portion extending to a discharge end of the tubular electrode which is of cross-sectional dimensions less than the cross-sectional dimensions of the hole to be plated, at least part of the workpiece including the hole being of conductive metal;   moving the tubular electrode relative to the workpiece to a predetermined horizontal position spaced above and centered on the hole;   moving the tubular electrode vertically relative to the hole into a plating position in which the insertion portion extends into the hole with the discharge outlet spaced a predetermined distance above an inner end of the hole;   connecting a power supply between the tubular electrode and conductive metal of the workpiece, whereby the inserted portion of the tubular electrode and the internal surface of the hole comprise electroplating electrodes;   connecting an inlet end of the tubular electrode to a supply of plating solution to direct a flow of plating solution through the tubular electrode, out of the discharge outlet, between the anode and interior surface of the hole, and out of an open end of the hole, whereby metal is deposited from the flow of plating solution onto the interior surface of the hole and the plating solution flow is continuous during a predetermined hole plating procedure; and   collecting spent plating solution flowing out of the open end of the hole in a collection device spaced below the plating system during hole plating, and directing the spent plating solution along a discharge flow path away from the workpiece and tubular electrode.   
     
     
         2 . The method of  claim 1 , wherein the workpiece has at least one electrical terminal, and the hole is a first solder cup at one end of the electrical terminal. 
     
     
         3 . The method of  claim 2 , wherein the workpiece is an electrical or hybrid electro-optical connector. 
     
     
         4 . The method of  claim 2 , wherein the workpiece is a finished electronics assembly including one or more connectors having multiple electrical terminals each having a solder cup at one end of the electrical terminal. 
     
     
         5 . The method of  claim 1 , wherein the tubular electrode comprises a needle anode and the hole to be plated is configured to act as a cathode when the power supply is connected between the needle anode and workpiece. 
     
     
         6 . The method of  claim 5 , wherein the needle anode is of noble metal material. 
     
     
         7 . The method of  claim 2 , wherein the tubular electrode comprises a needle anode having a first diameter less than the diameter of the solder cup, whereby the plating solution flow path through the solder cup includes an annular space of predetermined width between an outer surface of the needle anode and the inner surface of the solder cup to be plated. 
     
     
         8 . The method of  claim 7 , wherein the solder cup has a bore diameter of less than 0.25 inches and a depth-to-width aspect ratio of at least 2.0. 
     
     
         9 . The method of  claim 8 , wherein the ratio of the needle anode radius to the hole radius is approximately 0.6. 
     
     
         10 . The method of  claim 8 , wherein the ratio of needle anode radius to hole radius is in the range from around 0.1 to 0.6. 
     
     
         11 . The method of  claim 7 , wherein the width of the annular space between an outer surface of the insertion portion and inner surface of the solder cup is in the range from 0.01 to 0.04 inches. 
     
     
         12 . The method of  claim 7 , wherein the predetermined spacing between the needle anode and inner end of the solder cup in the plating position is approximately two times the diameter of the insertion portion of the needle anode. 
     
     
         13 . The method of  claim 12 , wherein the predetermined spacing is in the range from 0.04 to 0.06 inches. 
     
     
         14 . The method of  claim 2 , wherein the workpiece has a plurality of electrical terminals each having a respective solder cup at one end. 
     
     
         15 . The method of  claim 14 , further comprising terminating plating solution supply to the first solder cup after plating the inner surface of the first solder cup, moving the needle anode out of the first solder cup to a position where the discharge outlet is spaced above the open end of the first solder cup, moving the needle anode to a position above and centered over a second solder cup to be plated, moving the needle anode vertically until the insertion portion extends into the second solder cup with the discharge outlet spaced a predetermined distance above the inner end of the second solder cup, repeating the plating steps until the inner surface of the second solder cup is plated, and repeating the foregoing steps until all solder cups of the metal object requiring electroplating have been plated. 
     
     
         16 . The method of  claim 1 , wherein the collection device comprises a basin of non-conductive, semi-rigid elastomeric material, wherein the step of supporting the workpiece further comprises sealably engaging at least one opening in a lower wall of the collection basin over at least part of the workpiece spaced below the open end of the hole to be plated prior to commencing plating. 
     
     
         17 . The method of  claim 16 , wherein the workpiece comprises a connector having a plurality of electrical terminals having terminal portions projecting out of an insulating body of the connector, each terminal portion having a solder cup at its outer end. 
     
     
         18 . The method of  claim 17 , wherein the step of sealably engaging the collection basin to the workpiece comprises sealably engaging a plurality of openings in the lower wall of the collection basin which are of smaller diameter than the terminal portions of the electrical terminals over the terminal portions at a location spaced below the open ends of the respective solder cups. 
     
     
         19 . The method of  claim 18 , further comprising engaging non-conductive masking sleeves over terminal portions of the electrical terminals extending through said plurality of openings, whereby outer surfaces of the conductive terminal portions are shielded from spent plating solution flowing out of the open end of a respective solder cup during plating of the solder cup. 
     
     
         20 . The method of  claim 19 , wherein the masking sleeves are formed integrally with the respective openings. 
     
     
         21 . The method of  claim 19 , wherein the masking sleeves are formed separately from the basin and engaged separately over said terminal portions. 
     
     
         22 . The method of  claim 18 , wherein the step of collecting spent plating solution comprises directing plating solution flowing into the collection basin during electroplating of one of the solder cups out of a drain hole in the lower wall and into a discharge pipe for directing spent plating solution away from the plating system. 
     
     
         23 . The method of  claim 17 , wherein the step of connecting a power supply to the work piece includes electrically connecting the electrical terminals separately to the power supply. 
     
     
         24 . The method of  claim 23 , further comprising connecting the electrical terminals, a body of the workpiece, and a ground together as a common node. 
     
     
         25 . A method for electroplating an interior surface of a blind hole in a workpiece, the method comprising:
 electrically coupling a first power supply terminal to an electroplating anode, the electroplating anode including a plating solution inlet, a discharge outlet, and a passageway within the electroplating anode extending between and fluidly coupling the plating solution inlet and the discharge outlet;   positioning at least an end portion of the electroplating anode extending up to the discharge outlet within the interior surface of a blind hole in a workpiece which is at least partially formed of conductive material including the blind hole, with the end portion spaced from the interior surface and an inner end of the blind hole;   electrically coupling a conductive portion of the workpiece including the blind hole to a second electrical terminal of the power supply;   fluidly coupling a plating solution supply to the discharge outlet via the plating solution inlet and the passageway;   directing plating solution in a plating flow path from the plating solution supply through the internal passageway, out of the discharge outlet, through a space between the interior surface of the blind hole and the outer surface of the inserted end portion of the electroplating anode, and out of an open upper end of the blind hole; and   establishing an electric current between the interior surface of the blind hole and the electroplating anode through the plating solution such that metal is liberated from the plating solution and attached to the interior surface of the blind hole.   
     
     
         26 . The method of  claim 25 , wherein the workpiece has at least one electrical terminal, and the blind hole is a first solder cup at an end of the electrical terminal. 
     
     
         27 . The method of  claim 26 , wherein at least the inserted portion of the electroplating anode has a predetermined outer diameter of no more than 0.6 times the diameter of the solder cup. 
     
     
         28 . The method of  claim 26 , wherein the solder cup has a depth-to-width aspect ratio of at least 2.0. 
     
     
         29 . The method of  claim 26 , further comprising collecting spent plating solution flowing out of the open end of the solder cup in a plating solution drain of insulating material engaging over the first electrical terminal at a location spaced from the open end of the solder cup. 
     
     
         30 . The method of  claim 25 , wherein the workpiece comprises a connector having a connector body and a plurality of electrical terminals each having a solder cup at an end of the respective electrical terminal, the method further comprising moving the end portion of the electroplating anode out of a first solder cup after completion of electroplating, moving the electroplating anode into position over a second solder cup, positioning the end portion of the electroplating anode in the second solder cup, directing electroplating solution in the flow path out of the discharge outlet of the electroplating anode and through the space between the anode and solder cup to electroplate the second solder cup, and repeating the foregoing steps until each solder cup is electroplated. 
     
     
         31 . The method of  claim 30 , wherein the step of electrically coupling a second electrical terminal of the power supply to the conductive portion of the workpiece includes electrically connecting the plural electrical terminals of the connector, the connector body, and a ground together as a common node.