US 3860499 A
An apparatus and a method are disclosed for selectively electroplating a strip of material. The apparatus comprises a positioning means for receiving the strip, an open-top container adapted for holding a quantity of electrolyte solution therein, an engagement means for sequentially engaging the strip, an advancement means for moving the engaging means whereby a portion of the strip covers the open-top container, a seating means for engaging the upper surface of the strip to provide positive seating of the strip on the container, a retraction means for providing return movement of the engagement means when the strip is disengaged from the engagement means, at least one anode conductor for applying positive potential to the electrolyte solution within the container, and at least one cathode conductor for applying negative potential to the strip.
Claims available in
Description (OCR text may contain errors)
[ Jan. 14,1975
United States Patent Graham et al.
Primary Examiner-T. M. Tufariello Attorney, Agent, or FirmNorman J. OMalley; Donald R. Castle; Lawrence R. Fraley METHOD ELECTROPLATING APPARATUS AND  ABSTRACT An apparatus and a method are disclosed for selectively electroplating a strip of material. The apparatus H h Pm m w Imm Ka niDH eaia mm Aa w aW m a fl h Q m mmmm GmL, U mn len t r a 33.. ELSH x r 0 t n e V n I J 7 l.
 Assignee: GTE Sylvania Incorporated,
comprises a positioning means for receiving the strip,  Filed: Apr. 19, 1973 an open-top container adapted for holding a quantity [211 App] No 352 681 of electrolyte solution therein, an engagement means for sequentially engaging the strip, an advancement means for moving the engaging means whereby a por-  US. Cl. 204/15, 204/224 R tion of the strip covers the open-top container, :1 seat-  Int. C23b 5/48, B23p 1/02 ing means for engaging the upper surface of the strip  Field of Search..............I............ 204/224 R, 15
to provide positive seating of the strip on the container, a retraction means for providing return move-  References Cited ment of the engagement means when the strip is disen- UNITED STATES PATENTS gaged from the engagement means, at least one anode 3,723,283 3/1973 Johnson et 204/224 R conduct Q P i 1Dositive Potential to the elec- 3,745,105 7/1973 Kosowsky et al. 204 224 R trolyte 8011mm Wlthm the cqntamer, n at least one 3,746,630 7/I973 Kosowsky et 204/224 R Cathode co uctor for applying negative pOlemlal to FOREIGN PATENTS OR APPLICATIONS the 483,503 4/1938 Great Britain 204/224 R 19 Claims, 10 Drawing Figures PATENTED N 3,860,499 sum 2 OF 4 Z iQ-E 75' v .29 I 4 3 IPATENTEI] JAN 1 4l975 sum 3 or 4 PATENTEBJAN I 4l975 SHEEI 4 BF 4 ELECTROPLATING APPARATUS AND METHOD BACKGROUND OF THE INVENTION The invention relates to electrical deposition or plating of a metal or alloy of metals on areas of a strip of material to thereby provide desired characteristics such as improved electrical conductivity in these areas.
More particularly, this invention relates to an apparatus and method for achieving the electrical plating of a strip of material with precious metals thereby making it imperative that this plating be confined to desired areas on the material.
Previous methods for achieving localized electroplating have included dipping or submerging an article in a plating solution. These methods produce two unsatisfactory results. Firstly, the solution in the near vicinity of the article to be plated is soon spent and requires replenishing. Secondly, dip plating involves additional masking steps for each article to be plated in order to accomplish plating of a selected area on that article.
Another method utilized in plating of the variety described above is brush plating. When employing this method, however, a similar debilitation of the electrolyte soon occurs, resulting in a relatively slow rate of deposition of plating material in the article.
It is believed, therefore, that an apparatus and method which could successfully achieve the electrodeposition of metals on preselected areas of a strip of material while still overcoming the above cited disadvantages of the prior art would constitute an advancement in the art.
OBJECTS AND SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a method for electroplating selected areas on a strip of material.
It is a further object of this invention to provide an apparatus for achieving this plating.
In accordance with one aspect of this invention there is provided an apparatus for selectively electroplating a strip of material. The apparatus comprises a positioning means for receiving the strip, an open-top container for holding a quantity of electrolyte solution therein, an engagement means for sequentially engaging the strip, an advancement means for moving the engagement means a predetermined distance in a substantially rectilinear direction to transfer a portion of the strip to thereby cover the container, a seating means for engaging the upper surface of the strip and providing positive seating on the container, a retraction means for moving the engagement means said predetermined distance in a direction substantially opposite that of said advancement means, an anode for applying positive potential to the solution within the container, and a cathode for providing negative potential to the strip.
In accordance with another aspect of the present invention, there is provided a method for electroplating preselected areas on a strip of material. The method utilizes an open-top container having a quantity of electrolyte solution therein, an anode conductor for applying positive potential to the solution within the container, and a cathode conductor for applying negative potential to the strip, the method comprising the steps of positioning the strip within the apparatus, moving the strip a predetermined distance in a substantially rectilinear direction whereby a portion of the strip covers the open-top container, engaging the upper surface of the strip so that the strip is positively seated on the container, raising the solution level in'the container so that the solution engages the preselected areas on the strip, and electrically actuating the anode and cathode conductors to thereby accomplish the electroplating.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an isometric view of one embodiment of the apparatus of the present invention.
FIGS. 2-7 depict the various stages of operation of the apparatus of the present invention.
FIG. 8 is an isometric view of the open-top container of the present invention.
FIG. 9 is an isometric view depicting the adjustment means of the invention.
FIG. 10 illustrates one of the articles which can be plated utilizing the apparatus and method of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the above-described drawings.
With particular reference to FIG. 1, there is illustrated an isometric view of electroplating apparatus 11 in accordance with a preferred embodiment of the present invention. Apparatus 11 is shown to comprise a positioning means 13, an open-top container 15, at least one engagement means 17, an advancement means 19, a seating means 21, a retraction means 23, at least one anode conductor 25 (illustrated in FIG. 8), and at least one cathode conductor 27.
Positioning means 13 is adapted for receiving a strip of material 29 and comprises a substantially horizontally aligned surfaced member 31 on which strip 29 is placed. Surfaced member 31 consists of any material which is non-abrasive to the material being plated. In the preferred embodiment, strip 29 is of a steel or iron composition while surfaced member 31 is preferably plastic. Member 31 is supported within apparatus 11 by a plurality of upstanding leg members 33 each fixedly positioned on the base 35 of the apparatus. As shown in FIG. 1, a second surfaced member 31 is also utilized to provide a means for receiving strip 29 after the strip has been plated. Member 31' also has a plurality of upstanding leg members 33 affixed thereto and to base 35. Both surfaced members 31 and 31' are supported by a common support member 37, substantially centrally located in apparatus 11.
Support 37 also provides a means for-support for open-top container 15 which is shown as being oriented in a linear relationship with positioning means 13. Container 15 is adapted for holding a quantity of electrolyte solution (not shown) therein and comprises a housing 39 of corrosion resistant material, a reservoir, illustrated as a pipe 41, for transporting the solution, a valving means 43 affixed to pipe 41 for increasing or decreasing the rate of flow of the electrolyte within pipe 41, and a masking means 45 for directly engaging the strip. Pressure to reservoir 41 and container 15 is supplied by an externally located pump (not shown). Any of several types of pumping mechanisms is suitable for the present invention and further description of such devices is not therefore believed warranted. Masking means 45 has a plurality of plating ports positioned therein through which the solution will pass to engage the preselected areas to be plated on the strip. A more detailed description of open-top container will be given further in the specification with the description of FIG. 8.
E ngagement m ans 17 is oriented relative to positioning means 13 and is shown to comprise a plurality of pairs of fluid actuated cylinders 47 to each of which are affixed an upstanding pin 49. Although four pairs of cylinders are depicted, it can readily be seen that apparatus 11 could be further simplified to only include one pair. Additional simplification could also include the removal of surfaced member 31' as well as supports 33. However, the arrangement as illustrated in FIG. 1 is preferred.
Actuation of engagement means 17 is achieved by a corresponding actuation of a fluid supply means (not shown) to supply fluid through one of the connective members 51. In doing so, pins 49 are upwardly moved to mate with corresponding opening 53 provided in strip 29. Actuation of the fluid supply means is achieved by an electro-mechanical operation involving an electrical switch and a solenoid which is actuated by electrical current flowing therethrough. When the corresponding switch is closed, the solenoid acts to either open or close a valve, depending on the function required. It is not believed necessary to further define the above described operation as this and similar types of electro-mechanical devices are well known in the art. The present invention does provide however a preferred embodiment regarding the location for the electrical switches as well as means for actuating them.
With particular regard to actuation of pins 49 to engage openings 53 in strip 29, the electrical function is accomplished by engagement of switch 55, located on base 35, which in turn opens a valve to permit fluid to enter the pairs of cylinders 47. Switch 55 is engaged by a protruding arm 57 located on a movable carriage 59 of advancement means 19.
Advancement means 19 functions to move engagement means 17 a predetermined distance in a substantially rectilinear direction so that a portion of strip is transferred to cover open top container 15. Means 19 comprises, as described, at least one carriage member 59 and a drive means 61 fixedly attached to carriage 59. In the preferred embodiment, four carriage members are utilized, each commonly joined to a common drive shaft 63. Positioned on each carriage 59 is one of the four described engagement means 17, thereby providing means for engaging strip 29 at several locations. Carriages 59 in turn ride on a pair of substantially parallel shafts 65 each of which are firmly positioned within bearings 67. Bearings 67 are affixed at opposing ends of base 35. To drive carriages 59, drive means 61 is provided and comprises a fluid actuated cylinder member. Cylinder 61, as are cylinders 47, is actuated by an electro-mechanical assembly in which fluid is alternately supplied via pipes 69. Switch 71, located on an upstanding support 73 substantially adjacent seating means 21, provides the electrical portion of the above described arrangement and is actuated by an arm member 74 located on the upwardly displaced means 21. With switch 71 actuated as illustrated, drive means 61 thereby drives carriage 59 in the direction indicated.
To facilitate movement of strip 29 along surfaced member 31, a longitudinal guide means, illustrated as a pair above open-top container 15 and comprises an upper ram member 75 fixedly attached to and powered by a movement means 77. Ram member 75 is comprised of a metallic bar 79 with a solid portion 81 of resilient material such as neoprene rubber positioned thereon. A cathode conductor 27, illustrated as an elongated strip of electrically conductive material, is positioned on resilient strip 81 and is adapted for engaging strip of material 29 when ram 75 is lowered. Movement means 77 comprises a fluid actuated cylinder 83 which is at tached to bar 79 and maintained in position by supportive means 85.
Activation of seating means 21 is also achieved utilizing an electro-mechanical operation substantially similar to that of engagement means 17 and advancement means 19. Fluid is alternately supplied via piping 87 when electrical switch 89 is depressed by a second arm 91 located on carriage 59. As can readily be seen, switch 89 is actuated to provide the electrical portion of the above described movement only when carriage 59 is in the forward position, or advancing thereto.
When ram 75 lowers to engage strip 29, arm member 74 trips switch 93 located below switch 71. Engage ment of switch 93 serves to actuate a timer (not shown) and to provide the electrical portion of an electromechanical operation to alternate the fluid pressure in connective members 51. The timer, once started, provides the control means for supplying electrical energy to the anode and cathode members. Additionally, the timer controls valving means 43 to thereby open the valve and increase the level of electrolyte within open top container 15. The raised level passes through masking means 45 of the container and engages the preselected areas on the strip. With the electrical energy now present, electrodeposition of the electrolyte on strip 29 is achieved.
As stated, activation of switch 93 has the effect of reducing the fluid pressure in connective means 51 and therefore on cylinders 47. The result is that pins 49 are lowered to disengage openings 53 in the strip. When pins 49 lower, an arm member 95 located on one of the pins effects activation of switch 97 which in turn causes the return of carriage members 59. This is achieved by switch 97 providing the electrical portion of still another electro-mechanical function in which fluid pressure to drive means 61 is alternated in pipes 69. The result is that drive means 61 retracts drive shaft 63 the previously traversed rectilinear distance, this time in a substantially opposite direction. Thus, it can be seen that a retraction means has been provided for returning carriage 59 to the original starting position depicted in FIG. 1.
For a description of the various steps of operation of apparatus 11, reference is made to FIGS. 2-7 wherein several side elevational views of the electroplating apparatus in accordance with a preferred embodiment of the present invention are illustrated.
In FIG. 2, strip 29 is illustrated as being engaged by pins 49. Ram 75 is fully upwardly displaced and switch 71 is engaged. Switch 55 is also engaged and the apparatus is now in the preferred starting position. In order for apparatus 11 to remain in the present position so that an operator may position strip 29 thereon, an external master is utilized to effectively disengage switches 55 and 71, as well as the remaining switches of apparatus 11, from the current supply. With the master switch open, strip 29 is positioned on upstanding pins 49. The master switch is then closed starting the apparatus. As previously described, engaged switch 71 effects the advance of carriages 59. This movement in turn moves strip 29 in the substantially rectilinear direction indicated along surfaced member 31. This movement occurs until second arm 91 engages switch 89 which trips ram 75 down. Once ram 75 disengages switch 71, forward advance of carriages 59 is terminated. Ram 75 lowers to engage an upper surface of strip 29, thereby securing positive seating of strip 29 on open-top container 15. This seating is illustrated in FIG. 5. At the same time, ram 75 effects engagement of switch 93 which trips pins 49 down, thereby disengaging strip 29. At this time, the previously described timer is started to provide the electrical energy for a predetermined time period to the apparatuss cathode and anode members. Pins 49 in turn trip switch 97 which results in carriages 59 being returned as indicated in FIG. 6. In FIG. 7, the carriages have been retracted to a position in which switch 55 is once again actuated. Switch 55, as previously described, trips pins 49 upward to engage openings 53 within the strip. The operation cycle of the above-described timer is designed to terminate at this time. This timer is also electrically joined to the circuitry controlling movement of ram 75. Therefore, when the timer terminates its cycle, ram 75 is upwardly driven where it then once again actuates switch 71. Thus, it can be seen that a complete cycle of operation of apparatus 11 has been accomplished and strip 29 is once again ready for advancement.
In FIG. 8 there is shown a preferred embodiment for the open-top container 15 to be utilized with apparatus 11. Container 15 comprises a housing 39 of corrosion resistant material, a reservoir, illustrated as pipe 41 for supplying electrolyte solution to the container and a masking means 45 positioned on housing 39 and adapted for engaging the strip to be plated. In the preferred embodiment, anode conductor 25 is positioned within housing 39 and is adapted for having access to chamber 26 located with the housing. Although it is possible to utilize an open-top container having but one chamber 26 therein, in the preferred embodiment, several chambers are incorporated within housing 39, each having access to one of the several plating ports 28 located within masking means 45. Solution is supplied chambers 26 via an access slot 30 located within reservoir 41. As illustrated, housing 39 comprises a four-layered member in which upper layer 32 serves as a holder for masking means 45. Upper layer 32 is preferably of stainless steel composition while the material preferred for masking means 45 is of any suitable rubber composition, such as neopreme. Second and third layers 34 and 36, respectively, comprise the gasket region of container 15 and are preferably of essentially the same material as masking means 45. Bottom layer 38 of housing 39 is preferably of stainless steel composition and has a rounded portion 40 provided thereon for mating with reservoir 41. The joining of all four layers of housing 39, as well as the positioning of reservoir 41 against bottom layer 38, can be accomplished utilizing a bonding epoxy or similar type cementing agent.
With reference to FIG. 9, there is illustrated an adjustment means 101 which can be utilized with the present invention in order to decrease or increase the spacings between cylinders 47. This in turn decreases or increases the spacings between opposing upstanding pins 49 thereby providing a means whereby strips of material of different widths can be accommodated on apparatus 11. Adjustment means 101 consists of a pair of block members 103 and 103 respectively, each positioned on one of cylinders 47. Each block member is internally threaded and adapted for engaging a positioning shaft 105. Shaft 105 has a pair of opposing threaded portions 107 and 107' respectively, which are each oppositely threaded from the other. More specifically, portion 107 is provided with right-hand threading while portion 107' is provided with left-hand threading. Accordingly, block members 103 and 103 are provided with internal threading corresponding to the threaded portion engaged therein. Shaft 105 has a pair of non-threaded end portions 109 and 109' respectively, which are rotatably positioned within bearings 111 andlll respectively. Bearings 111 and 111' are fixedly positioned on carriage 59. An adjusting knob 113 is located on end 109 which, when rotated either clockwise or anticlockwise, will either draw cylinders 47 closer together or substantially increase their respective spacing. In conjunction with the above described motion, a channel 115 is provided in carriage 59 in which cylinders 47 may slidably move.
In FIG. 10 can be seen one example of the material that apparatus 11 is capable of electroplating. Strip 29 comprises a plurality of individual lead frame members 117 positioned therein in the manner indicated. One row 119 consists of several frames 117 therein, with strip 29 comprising several individual rows (the remaining indicated in phantom). In the enlarged portion of FIG. 10, one example of a frame member 117 is shown. Located on frame member 117 is an individual discrete area 121 (cross-hatched) which may be plated utilizing the apparatus and method of the present invention. Strip 29, usually of a stainless steel composition, will be later cut into sections of individual rows 119 each, after which each frame member 117 will be separated therefrom. Frame members 117 are each incorporated into integrated circuit packages with discrete areas 119 providing a bonding pad for the relatively small circuit or chip member. Electrical deposition of discrete area 121 would also include end portions 123 of the leads of frame 117, thereby substantially increasing the electrical conducting properties in these areas of the strip. In performing the above electro-deposition, a preferred electrolyte consists of an acidulated solution of gold salts, although several other electrolytic solutions are capable of being utilized with the present invention. Thus, there has been shown and described an apparatus and method whereby preselected areas on a strip of material have a metallic plating disposed thereon.
While there has been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.
What is claimed is:
1. An apparatus for Selectively electroplating a strip of material, said apparatus comprising:
positioning means adapted for receiving said strip of material in said apparatus;
an open-top container adapted for holding a quantity of electrolyte solution therein, said container oriented in linear relationship with said positioning means;
an anode conductor positioned substantially within said open-top container and adapted for applying positive potential to said electrolyte solution within said open-top container;
engagement means oriented relative to said positioning means and adapted for sequentially engaging said strip of material;
advancement means for moving said engagement means a predetermined distance in a substantially rectilinear direction to transfer a portion of said strip to cover said open-top container;
a substantially solid seating means substantially vertically oriented above said open-top container, said seating means adapted for engaging the upper surface of said strip to thereby provide positive seating of said strip on said container;
at least one cathode conductor positioned substantially within said seating means and adapted for applying negative potential to said strip of material; and
retraction means for moving said engagement means said predetermined distance in a direction substantially opposite to said rectilinear direction of said advancement means when said engagement means disengages said strip of material.
2. The apparatus according to claim 1 wherein said positioning means adapted for receiving said strip of material comprises a substantially horizontally aligned surfaced member, said member adapted for having said strip of material positioned thereon.
3. The apparatus according to claim 1 wherein there is included a longitudinal guide means, said longitudinal guide means relatedly positioned with said positioning means to facilitate the guiding of said strip in a rectilinear manner therealong.
4. The apparatus according to claim 3 wherein said longitudinal guide means comprises a pair of opposingly positioned upstanding wall members, said wall members adapted for engaging the sides of said strip of material.
5. The apparatus according to claim 1 wherein said open-top container adapted for holding a quantity of electrolyte solution comprises a housing of corrosion resistant material having at least one chamber located therein for receiving said electrolyte solution, a reservoir of electrically insulative and corrosion resistant material and adapted for transporting said electrolyte solution, said reservoir having access to said chamber within said housing, a valving means affixed to said reservoir for increasing or decreasing the rate of flow of said electrolyte solution within said reservoir, and a masking means positioned atop said housing, said masking means having a plurality of plating ports therein through which said electrolyte solution within said chamber may pass to engage said strip of material.
6. The apparatus according to claim 5 wherein said anode conductor adapted for applying positive potential to said electrolyte solution is positioned substantially within said housing member of said open-top container and is adapted for having access to said chamber within said housing.
7. The apparatus according to claim 5 wherein said housing of said open top container has a plurality of chambers located therein, each of said chambers hav-' ing access to one of said plating ports within said masking means whereby electrolyte solution within each of said chambers may pass to engage said strip of material.
8. The apparatus according to claim 7 wherein said anode conductor adapted for applying positive potential to said electrolyte solution is positioned substantially within said housing member of said open-top container and is adapted for having access to each of said chambers within said housing.
9. The apparatus according to claim 1 wherein said engagement means oriented relative to said positioning means comprises a plurality of upstanding pin members, each of said pin members fixedly attached to a motion means and adapted for engaging a'corresponding opening within said strip of material.
10. The apparatus according to claim 9 wherein said motion means comprises a plurality of fluid actuated cylinder members.
11. The apparatus according to claim 9 wherein said advancement means for moving said engagement means a predetermined distance in a substantially rectilinear direction to transfer a p'ortionof said strip to cover said open-top container comprises at least one movable carriage member and a drive means adapted for driving said carriage member, said motion means of said engagment means adapted for being positioned on said carriage member.
12. The apparatus according to claim 1 wherein said drive means comprises a fluid actuated cylinder member.
13. The apparatus according to claim 1 wherein said seating means substantially vertically oriented above said open-top container and adapted for engaging the upper surface of said strip to thereby provide positive seating of said strip on said container comprises an upper ram member, said ram member actuated by a movement means.
14. The apparatus according to claim 13 wherein said movement means comprises a fluid-actuated cylinder member.
15. The apparatus according to claim 13 wherein said cathode conductor adapted for applying negative potential to said strip of material is fixedly positioned on said upper ram member and is adapted for contacting said strip when said ram member engages the upper surface of said strip.
16. The apparatus according to claim 11 wherein said retraction means for moving said engagment means comprises a drive means adapted for driving said carriage member.
17. The apparatus according to claim 16 wherein said drive means of said advancement means and said drive means of said retraction means are the same.
18. A method for electroplating preselected areas on a strip of material utilizing an apparatus comprising an. open-top container adapted for holding a quantity of electrolyte solution therein, at least one anode conductor positioned substantially within said open-top container and adapted for applying positive potential to said electrolyte solution within said open-top container, a substantially solid seating means adapted for engaging the upper surface of said strip to thereby proraising the level of electrolyte solution within said open-top container whereby said solution engages said preselected areas on said strip; and applying electrical energy in a manner that said anode conductor provides positive potential to said electrolyte solution within said open-top container and said cathode conductor provides negative potential to said strip of material. 19. The method according to claim 18 wherein the raised level of said electrolyte solution maintains a constant pressure against said preselected areas on said strip of material during the plating operation.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,860,499
DATED 1 January 14, 1975 mvmroms) E l R. G J h L K h H.
S ner an z id fi fiopfiins ennet It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
Column 3, line 43 Please delete strip is and insert strip Column 5', line 4 Please delete "master is" and insert master switch is Column 6, line 51- Please delete "frame 117" and insert frame member 117 Column 8, line 33- Please delete "according to Claim 1" and 7 insert according to Claim ll Signed and sealed this 27th day of May 1.975.
C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks