Electroplating anode assembly

Abstract

An electroplating anode assembly and method for electroplating the plating area of a work-piece. The assembly includes a conductive element and a helical insulating coil. The conductive element can either be a straight conductive wire or a helically coiled conductive wire. The insulating coil is substantially equal in length to the conductive element and positioned around the conductive element for preventing the conductive element from contacting the plating area of the work-piece. The insulating coil extends continuously along the length of the entire electroplating portion of the conductive element. The anode assembly can be used to achieve uniform and adequate electroplating surfaces within recessed and enclosed plating areas of work-pieces that are conventionally difficult to electroplate due to its ability to be readily manipulated into various shapes. Further, anode assembly can be readily repositioned during the course of electroplating to further reduce the instance of localized areas of thick/thin deposition.

Description

FIELD OF THE INVENTION

[0002] This invention relates to electroplating apparatus and more particularly to an electroplating anode assembly.

BACKGROUND OF THE INVENTION

[0003] Achieving uniform and sufficient electroplating in recessed and enclosed spaces associated with dimensionally complex objects continues to be a difficult challenge for the industry. One of the main problems associated with electroplating such dimensionally complex objects is the variation in current density that exists from one area of the object to the next when the object is charged in an electroplating bath. Specifically, high current density areas usually exist on the raised areas of an object whereas low current density areas exist on recessed areas of the object. Since metal ions in solution generally take the path of least resistance, metal ions are deposited predominantly on high current density areas of an object resulting in an uneven metallic coating.

[0004] The deposition of a sufficient and even coat is critical in the microwave communication field as these deposition qualities are necessary to achieve the proper transportation of microwaves through waveguides, filters and housings with minimal signal loss. Internal anodes are used to create a catalytic effect on the anodic reaction that in turn promotes the deposit of metallic ions on low current density areas of an object. As shown in FIG. 1, internal anodes 10 which are typically rigid insoluble or soluble anodes, are positioned in a recessed plating area of a work-piece 13 which is to be electroplated. However, as shown when the recessed or enclosed areas within work-piece 13 are curved or complex, conventional rigid anodes 10 do not provide consistent deposition. Conventional rigid anodes can only be used if extra openings 14 are provided within the object to provide an exit path for the anode within the enclosed area as shown. This requires machining of extra openings into the work-piece adding expense and delay to the electroplating process.

[0005] U.S. Pat. No. 6,103,076 to Mizuno discloses an auxiliary anode element suitable for use in electroplating a bent tubular work-piece. While the anode element is provided with spaced apart spacers that contact the inner surface of a work-piece, the effectiveness of the anode element is limited by the use of a number of spacers along the anode. The number and position of spacers has to be predetermined for a particular work-piece which requires additional preparation time and expense when electroplating work-pieces with of different dimensions. Also, if one or more of the spacers detaches from the anode, it is possible for the anode to make contact with the cathode causing a damaging short. By adjusting the position of the anode within a workpiece it is possible to achieve an evenly distributed coating. This approach cannot be easily achieved using the Mizuno anode since it is difficult to adjust the position of the anode during plating. Further, the presence of the edges of spacers in close contact with the wall of the workpiece will cause plating discontinuities. Finally, the areas of the anode that are shielded by the vinyl tube will have no catalytic effect on the surrounding workpiece surfaces.

SUMMARY OF THE INVENTION

[0006] The invention provides in one aspect, an electroplating anode assembly for use in association with the plating area of a work-piece comprising:

[0007] (a) a conductive element having an electroplating portion and an outer diameter; and

[0008] (b) a helical insulating coil substantially equal in coiled length to the conductive element and having an inner diameter, said helical insulating coil being positioned around the conductive element for preventing said conductive element from contacting the plating area of the work-piece, said insulating coil extending continuously along the length of the entire electroplating portion of the conductive element.

[0009] The invention provides in another aspect a method of electroplating the plating area of a work-piece comprising the steps of:

[0010] (a) forming a conductive element;

[0011] (b) forming an insulating coil in the shape of a helical coil having a coiled length that is substantially equal to the length of the conductive element;

[0012] (c) inserting the conductive element within the insulating coil to form an electroplating anode assembly;

[0013] (d) positioning the electroplating anode assembly in close proximity to the plating area of the work-piece such that the outer insulating element prevents said conductive element from contacting the plating area of said work-piece; and

[0014] (e) utilizing the electroplating anode assembly to electroplate the plating area of the work-piece.

[0015] Further aspects and advantages of the invention will appear from the following description taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the accompanying drawings:

[0017] FIG. 1 is a schematic diagram of a prior art electroplating assembly that utilizes rigid electroplating anodes for electroplating a curved tubular work-piece;

[0018] FIG. 2A is a schematic diagram of one example implementation of the electroplating anode assembly of the present invention;

[0019] FIG. 2B is a partial cutaway view of the electroplating anode assembly of FIG. 2A;

[0020] FIG. 2C is a schematic diagram of the electroplating anode assembly installed within a plating area of a filter body work-piece;

[0021] FIG. 3A is a top view of the electroplating assembly of FIG. 2A positioned within a filter body work-piece;

[0022] FIG. 3B is a top view of the filter body work-piece of FIG. 3A ready for electroplating without the use of an electroplating anode;

[0023] FIG. 3C is a top view of the filter body work-piece illustrating the position of certain plating thickness measurements;

[0024] FIG. 3D is a graphical representation of the average copper deposit thickness comparison for the electroplating setup of FIGS. 3A and 3B at the measurements positions of FIG. 3C;

[0025] FIG. 3E is a graphical representation of the average silver deposit thickness comparison for the electroplating setup of FIGS. 3A and 3B at the measurements positions of FIG. 3C;

[0026] FIG. 3F is a top view of the electroplating assembly of FIG. 2A positioned within a typical filter body work-piece;

[0027] FIG. 4A is a schematic diagram of another example implementation of the electroplating assembly of the present invention;

[0028] FIG. 4B is partial longitudinal cross-sectional cutaway view of the electroplating assembly of FIG. 3A;

[0029] FIG. 4C is a schematic diagram of the electroplating anode assembly installed within a plating area of a waveguide body work-piece;

[0030] FIG. 5A is a side schematic view of the electroplating assembly of FIG. 4A positioned within a waveguide work-piece;

[0031] FIG. 5B is a side view of the waveguide work-piece of FIG. 5A ready for electroplating without the use of an electroplating anode;

[0032] FIG. 5C is a side view of the waveguide body work-piece illustrating the position of certain plating thickness measurements;

[0033] FIG. 5D is a side view of a section of waveguide body work-piece further illustrating the position of certain plating thickness measurements for each measurement section;

[0034] FIG. 5E is a graphical representation of the average copper deposit thickness comparison for the electroplating setup of FIGS. 5A and 5B at the measurement positions of FIG. 5C;

[0035] FIG. 5F is a graphical representation of the average silver deposit thickness comparison for the electroplating setup of FIGS. 5A and 5B at the measurement positions of FIG. 5C; and

[0036] FIG. 5G is a side view of the electroplating assembly of FIG. 5A positioned within a typical waveguide body work-piece.

DETAILED DESCRIPTION OF THE INVENTION

[0037] FIGS. 2A and 2B illustrate an example of the electroplating anode assembly 20 built in accordance with the present invention. Specifically, anode assembly 20 includes a conductive element 22 and an insulating coil 24 which are engaged with each other such that the assembly 20 allows for flexible movement of conductive element 22 within a plating area (i.e. the internal surface) of a work-piece.

[0038] Conductive element 22 is manufactured out of a conductive material and is preferably platinum wire having a diameter of 0.05 inches. Conductive element 22 is designed to be pliable such that it can be manipulated to take the shape of the plating area of a work-piece. It should be understood that conductive element 22 could be manufactured out of any electrically conductive material suitable for use as an electroplating anode (e.g. silver (non-inert), copper (non-inert), gold (non-inert), platinized titanium, titanium or stainless steel wire (inert)) and could have any physical dimension (i.e. diameter or length) that allows conductive element 22 to have sufficient flexibility for the contemplated application. It should be understood that in respect of non-inert copper, silver and gold, conductive element 22 would have to be periodically replaced as they are dissolved over time which is costly and time consuming. Also, these non-inert materials tend to produce a rough surface finish. Inert materials such as stainless steel can also be problematic as they may degrade and dissolve chromium and nickel into the plating solutions. Finally, it would be possible to form conductive element 22 as a braided wire as long as the flexibility of the anode assembly 20 is not compromised.

[0039] Insulating coil 24 is designed to be non-conductive and is preferably composed of a metal wire 26 coated by an insulator 28 (FIG. 2B). Insulating coil 24 is formed by first covering metal wire 26 with insulator 28 and then by winding the combination helically into a cylindrical shape having the desired overall length required for anode assembly 20. Since insulating coil 24 contains an insulator sheath 28, each individual coil is electrically non-conductive. In addition, an opening is present between each turn of the insulating coil 24 and the next turn.

[0040] Metal wire 26 is preferably stainless steel (28 AWG), although it should be understood that wire 26 could also be manufactured from various other suitable materials as long as the resultant wire is capable of maintaining a coiled shape. Insulator 28 is preferably Teflon™ (manufactured by E.I. Dupont of Delaware), although it should be understood that insulator 28 could also be manufactured from various other insulative type materials (e.g. synthetic resin, other fluoropolymers, polypropylene, CPVC, etc.) Finally, it should be understood that if metal wire 26 is made from a non-inert material, insulator 28 must form a completely air-tight seal between wire 26 and the plating solution in order for anode assembly 20 to be effective.

[0041] FIG. 2C shows anode assembly 20 positioned within the plating area 21 of a filter body work-piece 23. Since conductive element 22 is completely encased by insulating coil 24, insulating coil 24 prevents conductive element 22 from contacting the plating area 21 of work-piece 23 at every contact point. When anode assembly 20 is inserted into work-piece 23, the helical structure of insulating coil 24 allows insulating coil 24 to flexibly accommodate the various bends and curves associated with the plating area of filter body work-piece 23 as shown. As discussed, conductive element 22 is also sufficiently flexible so that it also bends within insulating coil 24 at the same various bends and curves. Accordingly, anode assembly 20 can be readily manipulated within filter body work-piece 23 to position conductive element 22 at desired positions within plating area 21. Finally, since insulating coil 24 extends in a continuous manner over conductive element 22, anode assembly 20 can be interchangeably used within a wide variety of work-pieces having different internal structures.

[0042] FIGS. 3A and 3B are top views of filter body work-piece 23 with and without electroplating assembly 20 of FIG. 2A. An experiment was conducted to determine the effect of electroplating deposition thickness with and without the use of anode assembly 20. FIG. 3A illustrates how anode assembly 20 can be recessed within various sunken areas 29 within filter body work-piece 23. FIG. 3B illustrates filter body work-piece 23 without anode assembly 20. The comparison was made by electroplating identical filter body work-piece 23 as shown in FIGS. 3A and 3B under the same conditions.

[0043] The experimental procedure consisted of plating filter body work-piece 23 with 200 micro inches of copper and 300 micro inches of silver as per Military Specification MIL-C-14550 and American Society for Testing and Materials ASTM B700-97 respectively. Each filter body work-piece 23 was originally composed of Aluminum prior to electroplating. Electroplating was then conducted accordingly to well known and conventional plating procedures. FIG. 3C illustrates where measurements were taken of the plating thickness of the copper and silver deposit. These measurements were made using a microscope. As shown in FIG. 3C, filter body work-piece 23 is composed of a number of resonators 30 and a jutting wall 32. In total, five thickness measurements were taken along a front edge on the jutting wall 32 and another five thickness measurements were taken from positions on the resonator 30 opposite. Specifically, measurements were taken from the bottom of each of jutting wall 32 and opposing resonator 30, and at 0.25 inches, 0.5 inches, 1.125 inches and 1.375 inches from the bottom).

[0044] Tables 1 and 2 contain the data obtained by measuring the plating thickness of the copper and silver deposit at the measurement positions shown in FIG. 3C with a microscope when anode assembly 20 is present within filter body work-piece 23 (FIG. 3A). Tables 3 and 4 contain the data obtained by measuring the plating thickness of the copper and silver deposit at the measurement positions shown in FIG. 3C with a microscope when the filter body work-piece 27 is plated alone (FIG. 3B). The thickness measurements listed in the Tables below are in micro inches (μ″) and the accuracy of measurement is ±33 micro inches.

TABLE 1
Copper Thickness Plated with Anode Assembly 20
		0″	0.25″	0.5″	1.125″	1.375″
	Resonator	263	263	263	263	263
	Wall	197	197	197	197	263
	Average	230	230	230	230	263

[0045]

TABLE 2
Silver Thickness Plated with Anode Assembly 20
		0″	0.25″	0.5″	1.125″	1.375″
	Resonator	263	263	329	329	329
	Wall	263	263	263	263	329
	Average	263	263	296	296	329

[0046]

TABLE 3
Copper Thickness Plated without Anode Assembly 20
		0″	0.25″	0.5″	1.125″	1.375″
	Resonator	197	197	197	263	263
	Wall	263	131	131	230	263
	Average	230	164	164	246.5	263

[0047]

TABLE 4
Silver Thickness Plated without Anode Assembly 20
		0″	0.25″	0.5″	1.125″	1.375″
	Resonator	0	131	131	263	263
	Wall	263	131	131	197	263
	Average	131.5	131	131	230	263

[0048] FIG. 3D is a graphical representation of the average copper deposit thickness comparison for the electroplating setup of FIGS. 3A and 3B at the measurement positions shown in FIG. 3C. FIG. 3E is a graphical representation of the average silver deposit thickness comparison for the electroplating setup of FIGS. 3A and 3B at the measurement positions shown in FIG. 3C.

[0049] The plating thicknesses measured on the surface of the filter body work-piece 23 illustrates the beneficial effect of utilizing anode assembly 20 as part of the electroplating process for a work-piece 23. As can be seen from Tables 3 and 4, for the filter body work-piece 23 that was electroplated without anode assembly 20 (i.e. FIG. 3B), there was little to no deposition of copper and silver in some areas. For the filter body work-piece 23 that is plated with anode assembly 20 (FIG. 3A), a relatively consistent thickness of copper and silver was achieved as illustrated in Tables 1 and 2.

[0050] Further, as can be seen, the beneficial effect of anode assembly 20 is more pronounced when considering the results associated with the silver deposit (i.e. in terms of magnitude of deposit thickness). Sufficient and uniform coating deposition on the internal surfaces of communication components used in space applications. In space applications, microwaves must be transported through waveguides, filters and housings with minimal signal loss. Since the microwaves are transported through the coatings (e.g. silver) of various communication components (e.g. filters, waveguides, etc.) the uniformity and thickness of these coatings directly impacts the quality of the finished part. Generally speaking the coating thickness is inversely related to signal loss.

[0051] FIG. 3F is a top view of anode assembly 20 of FIGS. 2A and 2B positioned within the plating area 21 of a typical filter body work-piece 23. The top end of anode assembly 20 is connected to a conventional plating power supply (not shown) using alligator clips (not shown) and the bottom of the anode assembly 20 is left unconnected. As discussed above, when anode assembly 20 is inserted into work-piece 23, the helical structure of insulating coil 24 allows insulating coil 24 to flexibly accommodate the various bends and curves associated with the plating area of filter body work-piece 23. As discussed, conductive element 22 is also sufficiently flexible so that it bends within insulating coil 24 at the same various bends and curves. Insulating coil 24. Accordingly, anode assembly 20 can be readily manipulated such that conductive element 22 can be positioned as desired within work-piece 23. The ability to mold anode assembly 20 to filter body work-piece 23 (or any other work-piece) provides improved electroplating quality as evidenced by the experimental results of Tables 1 to 4 and FIGS. 3D and 3E. Also, since the bottom of anode assembly 20 is left free, it is easy to reposition anode assembly 20 during electroplating which helps to avoid localized areas of thick/thin deposition on work-piece 23.

[0052] FIGS. 4A and 4B illustrate another example of an electroplating anode assembly 50 built in accordance with the present invention. Specifically, anode assembly 50 includes a conductive coil 52 and an insulating coil 54 which are engaged with each other such that assembly 50 allows for flexible movement of conductive coil 52 within a plating area of a work-piece.

[0053] Conductive coil 52 is manufactured out of a conductive material and is preferably a platinum wire having a diameter of 0.015 inches. The external diameter of conductive coil 52 is dependent on the internal dimensions of insulting coil 54 and the accessibility required for a particular electroplating application. Like conductive element 22, conductive coil 52 is designed to be pliable such that it can be manipulated to take the shape of the plating area of the work-piece. However, since conductive coil 52 is fashioned as a coil, conductive coil 52 has additional flexibility and can be manipulated to a greater degree than conductive element 22. It should be understood that again conductive coil 52 may be made out of any electrically conductive material suitable for use as an electroplating anode (e.g. silver (non-inert), copper (non-inert), gold (non-inert), platinized titanium, titanium or stainless steel wire (inert)). Further, since the ability for a wire to be flexible while maintaining a coiled shape is related to such properties as percent elongation and modulus of elasticity, it has been determined that conductive coil 25 should be made from a conductive material that has a percent elongation greater than 30% and a modulus of elasticity less than 200 Gpa.

[0054] As before, insulating coil 54 is designed to be non-conductive and is preferably composed of a metal wire 56 coated by an insulator 58 (FIG. 2B). As before, insulating coil 54 is formed by first covering metal wire 56 with insulator 58 and then winding the combination helically into a cylindrical shape having the desired overall length required for anode assembly 50. Since insulating coil 54 is covered with an insulating sheath, each coil is electrically non-conductive. In addition, an opening is present between each turn of the insulating coil 54 and the next turn. Metal wire 56 is preferably stainless steel (58 AWG). As before, insulator 28 is preferably Teflon™ (manufactured by E.I. Dupont of Delaware), although it should be understood that insulator 28 could also be manufactured from various other insulative type materials (e.g. synthetic resin, other fluoropolymers, polypropylene, CPVC, etc.)

[0055] FIG. 4C shows anode assembly 50 positioned in the plating area of a waveguide body work-piece 53. Since conductive element 52 is completely encased by insulating coil 54, insulating coil 54 prevents conductive element 52 from contacting the plating area 51 of a work-piece 53 at every contact point between anode assembly 50 and filter body work-piece 53. As shown, when anode assembly 50 is inserted into work-piece 53, the helical structure of insulating coil 54 allows insulating coil 54 to flexibly accommodate the various bends and curves associated with the plating area of filter body work-piece 53. Conductive element 52 is also sufficiently flexible so that it also bends within insulating coil 54 at the same various bends and curves. It should be noted that unlike the typically used prior art electroplating assemblies that utilize rigid electroplating anodes for electroplating a curved tubular work-piece (as shown in FIG. 1), it is not necessary to provide additional openings within work-piece 53. This results in improved ease of manufacturing, more even distribution of plating material and improved manufacturing accuracy due to a reduction in necessary part tooling and manufacture.

[0056] FIGS. 5A and 5B are top views of waveguide body work-piece 53 with and without electroplating assembly 50 of FIG. 4A. An experiment was conducted to determine the effect of electroplating deposition thickness with and without the use of anode assembly 50. FIG. 5A illustrates how anode assembly 50 can be manipulated to form to the two 90 degree bends 55 of waveguide body work-piece 53. FIG. 5B illustrates filter body work-piece 53 without anode assembly 50. The comparison was made by electroplating identical filter body work-piece 53 as shown in FIGS. 5A and 5B under the same conditions.

[0057] The experimental procedure consisted of plating a waveguide body work-piece 53 with 100 micro inches of copper and 300 micro inches of silver as per Military Specification MIL-C-14550 and American Society for Testing and Materials ASTM B700-97 respectively. Each waveguide body work-piece 27 was initially composed of Aluminum.

[0058] FIG. 5C illustrates a series of cross-sectional lines along the walls of waveguide body work-piece 53 along which measurements of electroplating thickness are taken. Specifically, electroplating thickness measurements are taken along section lines descending in inch increments along waveguide body work-pieces 53 of FIGS. 4A and 4B. FIG. 5D further illustrates the specific place where thickness measurements of the plating thickness of the copper and silver deposit are made along each of the section lines of FIG. 5C. As shown in FIGS. 5C and 5D, for each of the five section lines, four thickness measurements are taken on each inside wall (at points 1, 2, 3 and 4). As before, the thickness of the copper and silver deposits are measured using a microscope.

[0059] Tables 5 and 6 list data obtained by measuring the plating thickness of the copper and silver deposit at the measurement positions shown in FIGS. 5C and 5D with a microscope when anode assembly 50 is present within waveguide body work-piece 53 (FIG. 5A). Tables 7 and 8 list data obtained by measuring the plating thickness of the copper and silver deposit at the measurement positions shown in FIGS. 5C and 5D with a microscope when the waveguide body work-piece 53 is plated alone (FIG. 5B). As can be seen, averages of the individual wall measurements for each section are calculated. The thickness measurements listed in the tables are in micro inches (μ″) and the accuracy of measurement is ±33 micro inches.

TABLE 5
Copper Thickness with Anode Assembly 50
	Measure-	Measure-	Measure-	Measure-
	ment	ment	ment	ment
Part#	#1	#2	#3	#4	Average
0.1	99	99	99	164	115.25
1.1	131	66	66	131	98.50
2.1	131	66	131	99	106.75
3.1	66	66	66	99	74.25
4.1	66	131	66	66	82.25

[0060]

TABLE 6
Silver Thickness with Anode Assembly 50
	Measure-	Measure-	Measure-	Measure-
	ment	ment	ment	ment
Part#	#1	#2	#3	#4	Average
0.1	99	66	66	66	74.25
1.1	131	164	131	131	139.25
2.1	131	329	263	197	230.00
3.1	131	131	99	197	139.50
4.1	263	197	263	263	246.50

[0061]

TABLE 7
Copper Thickness without Anode Assembly 50
	Measure-	Measure-	Measure-	Measure-
	ment	ment	ment	ment
Part#	#1	#2	#3	#4	Average
0.2	66	197	131	66	115.00
1.2	33	33	33	33	33.00
2.2	0	0	0	0	0.00
3.2	0	0	33	16	12.25
4.2	16	16	16	16	16.00

[0062]

TABLE 8
Silver Thickness without Anode Assembly 50
	Measure-	Measure-	Measure-	Measure-
	ment	ment	ment	ment
Part#	#1	#2	#3	#4	Average
0.2	66	66	66	66	66.00
1.2	33	33	33	33	33.00
2.2	0	0	0	0	0.00
3.2	0	0	33	16	12.25
4.2	16	16	16	16	16.00

[0063] FIG. 5E is a graphical representation of the average copper deposit thickness comparison for the electroplating setup of FIGS. 5A and 5B at the measurements positions shown in FIGS. 5C and 5D. FIG. 5F is a graphical representation of the average silver deposit thickness comparison for the electroplating setup of FIGS. 5A and 5B at the measurements positions shown in FIG. 5C.

[0064] FIG. 5G is a side view of anode assembly 50 of FIGS. 4A and 4B positioned within waveguide body work-piece 53. As discussed above, when anode assembly 50 is inserted into work-piece 53, the helical structure of insulating coil 54 allows insulating coil 54 to flexibly accommodate the various bends and curves associated with the plating area of filter body work-piece 23. As discussed, conductive coil 52 is similarly flexible so that it also bends within insulating coil 54 at the same various bends and curves.

[0065] Accordingly, anode assembly 50 can be readily manipulated such that conductive element 52 can be positioned as desired within work-piece 53. The ability to mold anode assembly 50 to filter body work-piece 53 (or any other work-piece) provides improved electroplating quality as evidenced by the experimental results illustrated in Tables 5 to 8 and FIGS. 5E and 5F. Also, anode assembly 50 can be repositioned during electroplating in order to avoid localized areas of thick/thin deposition.

[0066] The plating thickness measured at various points on the internal surface of the waveguide body work-piece 53 clearly shows the effect of employing anode assembly 50 with superior flexibility than traditional prior art anode assemblies. Specifically, in some areas of the waveguide plated with no anode assembly 50 there was little to no deposition of copper and silver. The waveguide plated with the flexible anode showed a relatively consistent thickness of copper and an increase amount of silver deeper into the waveguide. It was also noticed that the effect of anode assembly 50 is more pronounced in the silver deposit, as far as its magnitude is concerned. These thicknesses are critical especially with the silver on the internal surface of the waveguide as microwaves are transmitted through them, and this impacts directly the quality of the finished part.

[0067] Accordingly, electroplating anode assemblies 20 and 50 can be used to achieve uniform and adequate electroplating surfaces within recessed and enclosed plating areas of work-pieces that are conventionally difficult to electroplate. Anode assemblies 20 and 50 achieve these improved results due to their ability to be readily manipulated into various shapes. This allows anode assembly 20 or 50 to be placed or formed into a recessed or enclosed area of a work-piece without the conductive element 22 or conductive coil 52 coming into contact with the work-piece. Further, since insulating coil 24 and 54 extends continuously over conductive element 22 and conductive coil 52, anode assembly 20 and 50 can be interchangeably used within a wide variety of work-pieces having different internal structures.

[0068] The flexible character of anode assemblies 20 and 50 allow for uniform distribution of current density in and around the plating area of work-piece. Uniform current density inside and outside a work-piece allows for the uniform deposition in terms of the adhesive, morphology and thickness of the deposited material on both internal cavities as well as on external surfaces of a work-piece. Finally, anode assemblies 20 and 50 can be repositioned during the course of electroplating to further reduce the instance of localized areas of thick/thin deposition. Finally, anode assembly 50 utilizes a conductive coil 52 that further enhances the flexibility of anode assembly 50 and is suitable for recessed and enclosed areas that require an especially high degree of flexibility. Since anode assembly 50 uses a coiled anode, the anode assembly 50 has a larger overall surface area than a straight wire-type anode, which will result in improved catalytic effect than is the case for conventional straight wire-type anodes.

[0069] While anode assemblies 20 and 50 have been discussed in association with filter body work-piece 23 and the waveguide body work-piece 53, respectively, it should be understood that anode assemblies 20 and 50 are applicable to any work-piece. Most advantageously, anode assemblies 20 and 50 can be used in association with work-pieces that have inaccessible bends, folds or sunken areas to achieve even and adequate electroplated material surfaces.

[0070] As will be apparent to those skilled in the art, various modifications and adaptations of the structure described above are possible without departing from the present invention, the scope of which is defined in the appended claims.

Claims

1. An electroplating anode assembly for use in association with the plating area of a work-piece comprising: (a) a conductive element having an electroplating portion and an outer diameter; and (b) a helical insulating coil substantially equal in coiled length to the conductive element and having an inner diameter, said helical insulating coil being positioned around the conductive element for preventing said conductive element from contacting the plating area of the work-piece, said insulating coil extending continuously along the length of the entire electroplating portion of the conductive element.

2. The assembly of claim 1, wherein said outer insulating coil comprises an inner element and an insulating coating deposited on said inner element.

3. The assembly of claim 1, wherein said conductive element is a straight wire.

4. The assembly of claim 1, wherein said conductive element is formed as a helical coil having an outer diameter less than the inner diameter of the helical insulating coil.

5. The assembly of claim 1, wherein said conductive element is made from a material selected from the group consisting of: platinum, titanium, gold, silver, copper, and stainless steel.

6. The assembly of claim 4, wherein said conductive element is made from a conductive material that has a percent elongation greater than 30% and a modulus of elasticity less than 200 Gpa.

7. A method of electroplating the plating area of a work-piece comprising the steps of: (a) forming a conductive element; (b) forming an insulating coil in the shape of a helical coil having a coiled length that is substantially equal to the length of the conductive element; (c) inserting the conductive element within the insulating coil to form an electroplating anode assembly; (d) positioning the electroplating anode assembly in close proximity to the plating area of the work-piece such that the outer insulating element prevents said conductive element from contacting the plating area of said work-piece; and (e) utilizing the electroplating anode assembly to electroplate the plating area of the work-piece.

8. The method of claim 7, further comprising the step of repositioning the electroplating anode assembly at different positions within the plating area of work-piece during the plating process.

9. The method of claim 7, further comprising the step of forming the insulating coil by depositing an insulating coating on a coiled element.

10. The method of claim 7, further comprising the step of forming the conductive element as a straight wire.

11. The method of claim 7, further comprising the step of forming the conductive element as a helical coil having an outer diameter less than the inner diameter of the insulating coil.

12. The method of claim 7, wherein said conductive element is made from a material selected from the group consisting of: platinum, titanium, gold, silver, copper, and stainless steel

13. The assembly of claim 11, wherein said conductive element is made from a conductive material that has a percent elongation greater than 30% and a modulus of elasticity less than 200 Gpa.