CONTINUOUS CONTACT PLATING APPARATUS

Abstract: A contact plater apparatus (II) and method for plating selected areas of a web workpiece (39) wherein the web workpiece (39) and anode (107) are in close proximity, separated only by the brush belt (35) that contacts the web workpiece (39). A box manifold continually replenished with plating solution provides the brush belt (35) with plating solution from openings (121) in a header (12) as the solution passes over an anode (107). The brush belt (35) of open cell foam or other absorbent material wicks up the plating solution and brushes it on the desired spot on the cathodic web workpiece (39). The brush belt (35) is guided past the box manifold (83) in an accurately defined path. The web workpiece (39) and brush belt (35) are brought into precise contact at the openings in the header (12) of the box manifold (83) where the plating takes place. The guide (36) for the web workpiece (39) is adjustable along more than one axis to provide for contacting the brush belt (35) with the web workpiece (39) with a range of contact pressure and angles. Each guide (36) is custom built for the parts to be plated.

Description: CONTINUOUS CONTACT PLATING APPARATUS Cross-Reference to Related Application This application is a • continuation-in-part of application Serial Number 654,760, filed September 25, 1984 for Continuous Contact Plating Method and Apparatus. Background of the Invention Field of the Invention The present invention relates generally to improvements in plating apparatus, and more particularly pertains to new and improved zone plating apparatus wherein precious metals such as gold, silver or palladium are plated on electrical contact areas on electrical components. Brief Description of the Prior Art Those concerned with the development of plating apparatus for plating precious metals such as gold and silver or palladium onto electrical components have long recognized the need for efficiency in the application of the precious metal to the workpiece, both in terms of control over the defined area that is plated and the thickness of the plating material. United States Patent No. 4,064,019 for a continuous contact plater method issued December 20, 1977 describes a system which is directed towards this end. However, the system falls short in several respects. It fails to accurately control the thickness of the precious metal being deposited on the selected area of the electrical components. It fails to plate an accurately defined area. It can only plate one zone on a component at a time. It is designed to plate curved surfaces. The present invention overcomes the shortcomings of the apparatus in United States Patent No. 4,064,019 and all the prior art in this field. Specifically, the present invention can plate multiple zones, at one time, including front and back. It is also capable of plating flat or curved surfaces on a component. Summary of the Invention The present selective contact plater apparatus provides the minimum necessary amount of plating solution to the web workpiece and plates at minimum thickness on curved or flat surfaces, multiple zones at one time, by keeping the anode very close to the web workpiece and utilizing a continuous brush belt that only touches the web workpiece with the electrified plating solution at the desired zone. The belt is constructed using materials and methods that make it structurally stable and impervious to the plating solution and also only apply a minimum amount of plating solution to the web. The belt moves against and across the web workpiece at a "rate of speed that facilitates efficient plating. The guide for the web workpiece is guided along a precisely controlled path. The guide for the web workpiece is adjustable along more than one axis to provide for contacting the brush belt with the web workpiece with a range of contact pressure end angles. Brief Description of the Drawings The objects and many of the attendant advantages o this invention will be readily appreciated as the same become better understood by reference to the following detaile description when considered in conjunction with th accompanying drawings in which like references numeral designate like parts throughout the figures thereof, an wherein: Figure 1 is a perspective illustration of th continuous contact plating apparatus of the present invention; Figure 2 is a partial perspective illustration of continuous plating apparatus showing the brush belt; Figure 3 is a perspective of the continuous contac plating apparatus showing the guide device of the brush bel attached to the plating fluid chamber; Figure 4 is an exploded perspective showing the thre main parts of the guide for the brush belt; Figure 5 is a perspective of a portion of th continuous contact plating apparatus according to the presen invention showing the anode positioned with respect to th -plating solution chamber; Figure 6 is a perspective showing a portion of th continuous contact plater apparatus of the present invention the anode chamber and the escape channels for the platin solution; Figure 7 is a perspective of the brush belt utilize by the continuous contact plating apparatus of the presen invention; Figure 8 is a side perspective of an alternat embodiment for the guide device for the web workpiece to b plated; and Figure 9 is a front perspective of the guide devic for the web workpiece shown in Figure 8. Description of the Preferred Embodiment Referring first to Figure 1, which illustrates th major features of the continuous contact plating apparatus 1 according to the present invention, a web workpiece 39 i shown coming into contact with the brush belt 35 whic effectively plates selective portions of the continuous we workpiece 39. The web workpiece 39 is essentially continuous web or a strip containing many pieces of electrica components which are to be selectively plated with a preciou metal electrical conductor such as gold, palladium or silver, for example. The web workpiece 39, as is understood in th art, is charged cathodically. The manner in which this i "accomplished is not shown. Neither are the takeup and suppl reels which cause the web workpiece 39 to move past th contained supply of plating solution 12 and the brush belt 35. The brush belt 35, as is more clearly seen in Figur 7, is a continuous loop having a backing 69 that i structurally stable and chemically inert to the platin solution utilized. A material such as titanium is preferred This backing has a plurality of apertures 71 punched therei along its length to allow plating solution fluid to pas therethrough to the brush portion 35, which is a highl absorbent material and chemically inert to the platin solution. An open cell urethane foam or other materials suc as felt or neoprene is preferred. The absorbent material mus be capable of allowing the solution to pass through from on side to the other and be held by the material. The brush belt 35 moves over a series of pulleys only one of which is shown, 31._ Pulley 31 can be considere the driving pulley that moves the belt past the face or heade 12 of the contained supply of plating solution. Pulley 31 i rotated by driving its rotary shaft 33. The contained supply of plating solution and it header 12, as well as the guide 37 for the brush belt 35 whic is fastened thereto, is contained within a framework which ha 'an upper shelf and a lower shelf 14. The upper shelf 1 carries support structures 15 and 17 which in turn suppor latching blocks 21 and 19, respectively. Latching blocks 2 and 19 are moved back and forth on their respective shafts b way of knobs 29 and 27, respectively. Knob 29, for example drives the threaded shaft 20 which threadably engages latching block 21, causing it to move back and forth on carrier shaft 22. A similar type of adjustable mechanism is utilized at the bottom plate 14 for the plater apparatus. Support blocks 45 and 47 support hinge blocks 49 and 51, respectively, by way of circular shafts such as 40, for example. The knob-screw apparatus 57 and 59, respectively, turn within screw support plates 53 and 55, respectively, to rotate bolt 60, for example, which threadably engages pivotal block 51, causing it to ride back and forth on support shaft 40. To ensure that the web workpiece 39 makes correct contact with the brush belt 35 moving within the pathway 37, a contact arm such as 63, which is pivotally connected to pivot block 51, is swung up and engaged with latching block 19 by way of a dowel pin 24, for example, which slides through the latching block 19 into its respective connecting head. The workings of the contact arm are more clearly illustrated when unlatched on the right-hand side of Figure 1, wherein the contact block 65 is clearly illustrated. The connecting head " 61 has an aperture 62 therein for receiving the connecting pin. The contact block 65 can be positioned on the arm 63 by way of moving the block in the slots 64 therein by loosening the thumbscrews 65. Once disconnected from connecting block 21, the entire contact arm may be pivoted down around pivot hinge 67. Referring now to Figure 2, the guide means 37 for the brush belt 35 is more clearly illustrated. The brush bel guide 37 has a pair of major parts, upper fastening bar 75 an lower fastening bar 73, which fasten to the front of the contained supply of plating solution 12 by way of countersun bolts 77 in the upper bar 75 and bolts 76 in the lower bar 75. Both the upper and lower bar 75 and 7 ' 3, respectively, overla the edges 69 of the brush belt 35, thereby guiding it across the face of the contained supply plating solution 12 in both horizontal and vertical direction. Located behind the guide 37 is the anode which has electrical connector arms 41 and 43 shown in Figure 2 to whic electrical connection is made. Referring now to Figure 3, the contained supply o plating solution 12 is more clearly illustrated, as is th brush belt guide 36. The contained supply of plating solutio 12 is essentially a box manifold 83 which has an inlet port 8 and an outlet port 82 through which plating solution flows. The plating solution can escape from the box manifold 83 an pass through the apertures 87 in slide bar 85, which is par of the brush belt guide 36. Apertures 87 are shown as forme to match the apertures in the titanium backing for the brus belt. However, such an arrangement should not be taken a limiting. Again, the electrical connector tabs 41, 43 and 7 for the anode located within the avenue of escape for th plating solution from the box manifold 83 are shown. Referring now to Figure 4, the major parts of the brush belt guide mechanism 36 are most clearly illustrated. Essentially, the brush belt guide mechanism 36 is made up of three parts. The slide bar 85, as already discussed, has a plurality of apertures located therein and stepped edges having two steps 99 and 97 at both edges of approximately equal distance. This slide bar 85 is preferably made out of a high density and smooth material like TEFLON or TIVAR or material having similar characteristics. Slide bar 85 overlays the front of the box manifold 83 and covers the avenue of escape of the plating solution out of the box manifold 83. It is held fast to the front by means of the upper fastening bar 75 and the lower fastening bar 73. Both the upper bar 75 and lower bar 73 have a three-step edge, 101, 103 and 105, which overlays the two-step edge on the slide bar 85. However, the middle step 103 of the fastening bars is greater than the first step 99 of the slide bar so that a gap 89 and 91, respectively, slightly greater than the thickness of the titanium metal ribbon which backs the brush belt is created, allowing the brush belt to slide within the gap. "Also, the distance between the first step 99 of the top edge and first step 100 of the bottom edge of slide bar 85 is slightly greater than the width of the brush belt titanium backing. The apertures 93 in the upper fastening bar 75 and the apertures 95 in the lower fastening bar 73 are countersunk apertures to receive the Allen head bolts 77 and 76, respectively. Referring now to Figure 5, the preferred anod structure to be used with the box manifold 83 is illustrated. The anode 107 is shown as a mesh or screen of platinum cla material, preferably platinum wire or other chemically iner material having similar characteristics, which has electrica connector tabs 41, 43 and 79 connected thereto and extendin therefrom in channels 113, 115 and 117, respectively. Th anode 107 lies within a recess 109 (Figure 6) in the face o the box manifold 83, thereby providing a flat surface for th guide. Three pieces of the brush belt guide 36 to overlay th apertures 109 and 111 in the face of the box manifold 83 ar threaded to receive the Allen head bolts that pass through th upper fastening bar 75 and lower fastening bar 73 of the brus belt guide apparatus 36. Figure 6 more clearly illustrates the avenue o escape for the plating solution contained within the bo manifold 83. The apertures 121 in the face of the bo manifold are structured to correspond to the apertures 87 i "the slide bar 85 of the brush belt guide apparatus 36. However, such an arrangement should not be considered a limiting, as other relationships may be found useful. The bo manifold 83 is made of PVC material or some other material o equally inert characteristics to the plating solution. The brush belt essentially has two major components a loop of material which is a carrier for the loop o absorbent material which is the brush. The carrier i preferably a flat titanium ribbon of 10 mil thickness. I could also be made out of fiberglass plastic or simila material which has structural stability and is chemicall inert to the plating solution utilized. Assuming the titaniu ribbon is used as the carrier, it is formed into a loop b welding the two ends together. Then the apertures are place therein approximately along a line that is at the center o its width, which apertures are of a desired length and widt as may be, to some extent, dictated by the particula electrical components being plated. An adhesive which can withstand the pH ranges an temperature ranges to which the brush belt will be subjecte is utilized to glue the absorbent brush material to th carrier. The adhesive must be chemically inert to the platin solution utilized and must be compatible with the brus material that is being glued to the titanium loop. A foam, felt, neoprene or similar material which wil " be the brush portion of the brush belt is formed to be o about equal width with the titanium loop and of equal length. It is preferred that an open cell urethane foam be utilize which has homogeneous pores and grain structure. It has bee found that such a material exhibits excellent capillary actio in drawing plating solution quickly from the contained suppl in the box manifold to the surface that is to contact th electrical apparatus to be plated. In operation, the belt is the carrier for the platin fluid in that it transmits the plating solution from the bo manifold to the exact area on the part being plated, applyin it by a brushing lateral movement across that area. Th plating solution delivered by the brush belt is electricall charged. The belt is driven in a direction opposite to o with the web workpiece at a speed that will most effectivel break down the cathodic film buildup on the interface o contact point between the brush belt and web workpiece. Referring now to Figure 8, an alternate preferre embodiment for the structure that receives and guides the we workpiece 39 past and into contact with the brush belt 35 i illustrated. Figure 9 illustrates the same embodiment from different perspective. The apparatus illustrated in Figures and 9 is designed to provide highly controlled placement o the web workpiece 39 with respect to the brush belt 35. Thi includes not only the amount of pressure with which the we "workpiece 39 contacts the brush belt 35 but also the angle a which the web workpiece 39 engage the brush belt 35. This control of the relationship between the we workpiece 39 and brush belt 35 is accomplished by th structure illustrated in Figures 8 and 9 which include threaded control knobs 15, utilized for course adjustments, and control knob 161 used for fine adjustments, in moving the rigid backing plate 167 which holds the contoured guide 169 that is channeled to receive the specific construction of the parts in the web workpiece 39. It should be recalled that the brush belt 35 can also be custom contoured for a particular strip of parts. Figures 8 and 9 illustrate the continuous contact plating apparatus built according to the present invention. The brush belt 35 moves over a series of pulleys 31, 125 and 127. Pulley 31 is the driving pulley which is connected by shaft 33 to a driving means 123. Driving pulley 31 moves the brush belt 35 past the header 12 which is contained within a framework having an upper shelf 13 and a lower shelf 14. The upper shelf 13 carries a pair of shafts 131 and 129. The lower shelf 14 carries a pair of shafts 133 and 135 fastened by any convenient means, such is bolts. A block 137 having bearing surfaces 132 and 134 at opposite ends thereof is journalled on shafts 131 and 133, respectively, for the purpose of sliding along the length of shafts 131 and 133. Block 139 having a pair of bearing surfaces 130 and 136 is journalled on shafts 129 and 135, respectively, for the purpose of sliding back and forth on these shafts. Shafts 131 and 133 are held parallel by a plate 143 which receives the end of shafts 131 and 133 and fastens such ends to the plate by means of threaded bolts 139 and 147, respectively. I turn, shafts 129 and 135 are held parallel by plate 145 whic receives the ends of shafts 129 and 135 and holds them fast b means of threaded bolts 146 and 148. Threaded shaft 151 i journalled through a plate 143 and engages block 137 rotatabl but fixedly at about its center location 152. In this manner, movement of shaft 151 along an axis parallel to shafts 131 an 133 will cause movement of block 137 along these shafts in smooth and easy manner as the result of the bearing surface 132 and 134. At the other end of the rigid backing block 167 fo the receiving and guiding device for the web workpiece 39 i association with the shafts 129 and 135, a threaded shaft 15 is rotatably but fixedly attached to block 139 at its cente 154. Movement -of shaft 153 along an axis parallel to shaft 129 and 135 will cause movement of block 139 along thes shafts in a smooth manner because of bearing surfaces 130 an 136. Movement of both blocks 139 and 137 along th respective shafts 129, 135 and 131, 133 is the result o "turning threaded knob 155 which threadably engages shaft 15 and threaded knob 157 which threadably engages shaft 153. Turning knobs 155 and 157 in a clockwise direction will caus shafts 151 and 153, respectively, to be drawn outwardly pulling blocks 137 and 139, respectively, with it. Turnin threaded knob 155 and 157 in a counterclockwise direction, pushes shafts 151 and 153 inwardly towards the brush belt 35, pushing the blocks 137 and 139 with them. Blocks 137 and 139 are connected together by a rigi block 141. Mounted on this block 141 is a plate 159 which has a threaded shaft 163 journalled therethrough and has fixedly mounted on its end a knurled knob 161. Threaded shaft 163 engages block 165 threadably causing block 165 to be moved up and down shaft 163 along its length upon rotation of knurled knob 161 in a clockwise or counterclockwise direction. Block 165 is fixedly attached to a very rigid backing plate 167 to which is fastened the relatively friction free channeled guiding means 169 for the web workpiece 39. The channeled receiving and guiding device 169 is constructed ver similar to the guiding construction 36 for the brush belt (Figures 3 and 4). A major difference would be the construction of the center piece 85 which would be shaped not with aperatures 86 therein, but in a manner to compliment the shape of the parts on the web workpiece 39. As a result, the web workpiece 39 is held to a very precise course of travel past the brush belt 35 which in turn is also held to a very precise course of travel past the header wherein it soaks up the charged plating solution needed to accomplish the plating function. The mechanism shown in Figures 8 and 9 determine this precise course of travel of web workpiece 39. A manua adjustment of knobs 155 and 157 is a course adjustment tha locates web workpiece 39 in proximity or minimal contact wit brush belt 35. Movement of knobs 155 and 157 causes th shafts 151 and 153 to move, pulling with them block 137 an 139 which jointly pull with them block 141 to which i attached the fine adjustment mechanism having a plate 159 an 165 connected to block 141 and backing block 167 respectively. Movement of shafts 151 and 153 causes movemen of rigid backing plate 167 in the same direction throug threaded screw 163. Once the course adjustment of the backin plate 167 is established by knobs 155 and 157, the fin adjustment is accomplished by means of knurled knob 161 b turning it clockwise or counterclockwise causing movemen towards and away from brush belt 35 in very fine or smal increments. Web workpiece 39 need not come into contact wit brush belt 35 along an axis perpendicular to the brush belt 3 as illustrated in Figures 8 and 9. Rods 131, 133 and 129, 13 " can, if desired, be adjusted to extend away from header 12 a any angle desired, depending upon the construction of th individual parts on the web workpiece 39, the contour of th brush belt 35, and the particular part of a web workpiece 3 upon which plating is desired. Changing the angle at whic shafts 131, 133 and 129, 135 extend from the header 12 is easily accomplished once presented with the possibility of doing so. Accordingly, such a structure is not illustrated. It should be understood that the foregoing disclosure relates only to the preferred embodiments of the invention and that modifications may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims. For example, a squeegee apparatus may be placed at a location on the brush belt after it passes by the contained source of supply for the plating solution in order to squeeze out the plating solution remaining in the belt after the plating operation. In addition, .plating solution may be added to the brush belt at a place other than from the box manifold and in addition to the solution provided to the belt by the box manifold. Although the method and apparatus described is most advantageously usable with systems for plating gold, other materials and platable substances can be plated by the method and apparatus, such as silver, palladium, copper, nickel, tin or tin/lead, for example. Indeed, the system could also be used to selectively strip metal from a workpiece or apply lubricant thereto, or remove a fluid therefrom.

Claims: CLAIMS WHAT IS CLAIMED IS: 1. A selective contact plater ' for continuousl plating a plurality of zones, comprising: a contained supply of plating solution having an avenue of escape; an anode mounted in close proximity to the avenue of escape for the plating solution so that all the plating solution leaving the supply passes over the anode; a porous material mounted in close proximity to said anode and the avenue of escape for the plating solution for absorbing some of the plating solution after it has passed the anode; means for moving a web workpiece to be selec¬ tively plated past said porous material; and means for receiving the web workpiece to be selectively plated, in the area of the avenue of escape for the plating solution, and guiding said web workpiece into precise contact with the belt at those points on the parts in the web workpiece that are to be plated. 2. The selective contact plater of Claim 1 furthe comprising a means for guiding said porous belt past the anod and avenue of escape of the plating solution supply. 3. The selective contact plater of Claim 2 wherein said guiding means also functions to direct the plating solution from the supply to the porous belt. 4. The selective contact plater of Claim 3 wherein said guiding means comprises a relatively friction-free material that is structurally stable and impervious to the pH and temperature ranges of the plating solution. 5. The selective contact plater of Claim 4 wherein said guide means comprises three main parts, the first part has apertures therein and overlap the avenue of escape for the plating solution and the anode, the second and third parts overlay the edges of the first part and hold it fast to the contained supply of plating solution. 6. The selective contact plater of Claim 5 wherein said second and third parts further, overlay the edges of said porous belt, thereby guiding the belt in a defined path over the first guide part. 7. The selective contact plater of Claim 1 wherein said porous material is a belt that comprises a continuous loop of material capable of absorbing plating solution. 8. The selective contact plater of Claim 7 wherein said porous belt further comprises a continuous loop of material that is structurally stable and inert to the plating solution, said loop of material having recesses therein to allow plating solution to pass therethrough, said absorbing material being mounted thereon over the recesses. 9. The selective contact plater of Claim 8 wherei said continuous loop of structurally stable material comprise titanium and said absorbent material comprises an open-cel foam. 10. The selective contact plater of Claim 8 wherei said open-cell foam is a polyurethane material having uniform grain structure. 11. The selective contact plater of Claim 1 wherein said open-cell foam material is held to said titaniu belt by an adhesive capable of withstanding the pH an temperature ranges in the plating process. 12. The selective contact plater of Claim 1 wherei said receiving and guiding means comprises: a rigid backing means extending the length of the avenue of escape of the plating solution; and a guiding means extending the length of the backing means for slidably receiving the strip of parts. 13. The. selective contact plater of Claim 1 wherein said guiding means is channeled to receive only th "particular parts being plated and guides the web workpiec past said porous material at a preferred angle. 14. The selective contact plates of claim 1 further comprising: means attached to said receiving and guiding means for controllably moving the web workpiece received by said guiding means into contact with said porous material. 15. The selective contact plater of Claim 14 wherein said controllably moving means includes: a plurality of parallel shafts extending outwardly and away from said porous material; a plurality of sliding bearings journalled, one each on said plurality of shafts; a pair of first adjusting means, one at each end of said rigid backing means for moving the sliding bearings-along the length of said shafts; a second adjusting means attached to said bearings and to said rigid backing means for moving the backing means towards and away from said porous material in controlled small distances. 16. The selective contact plates of Claim 15 wherein said plurality of parallel shafts extend outwardly and perpendicular to said porous material.

Inventors: BACON JEFFERY E, CRAIG JAMES E, PEDERSEN MARK K, BACON, JEFFERY, E., CRAIG, JAMES, E., PEDERSEN, MARK, K.
Applicants: ROBBINS & CRAIG WELDING & MFG, ROBBINS & CRAIG WELDING AND MANUFACTURING CO.
Application year: 1986
Main classification: C25D17
IPC codes: C25D5, C25D17, C25D19