1. A rack for use in electroplating, said rack comprising:
- one or more support arms, said one or more support arms having an axis;
wherein said one or more support arms rotate around said axis;
one or more clips affixed to said one or more support arms, each of said one or more clips further comprising a first prong;
wherein said first prong is configured to contact the interior wall of a work piece at a single contact point;
wherein said one or more clips rotate in conjunction with said one or more support arms when said one or more support arms rotate around said axis; and
one or more first buoyant devices directly affixed to said one or more support arms, wherein said one or more first buoyant devices rotate in conjunction with said one or more support arms; and
wherein movement of said one or more first buoyant devices causes said one or more support arms rotate around said axis.
A rack for supporting work pieces during electroplating including a frame having respective first and second side portions and top and bottom portions, the first and second sides attached to each other through top and bottom portions; one or more support arms extending between the frame first and second sides, the one or more support arms affixed to the frame to allow rotational movement of the one or more support arms; one or more clips affixed to the support arms, the one or more clips configured to hold a work piece; and a buoyant device affixed to the one or more support arms.
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Patent #US 4,746,416 A
Current AssigneeWestern Industries Incorporated
Sponsoring EntityWestern Industries Incorporated
|AQUACULTURE ASSEMBLY AND METHOD|
Patent #US 20130186345A1
Current AssigneeYvonne E. Young, Steven J. Leslie
Sponsoring EntityYvonne E. Young, Steven J. Leslie
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Patent #US 3,901,788 A
Current AssigneeDare Pafco Inc. Urbana OH
Sponsoring EntityDare Pafco Inc. Urbana OH
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Patent #US 2,722,513 A
Current AssigneeChester G. Clark
Sponsoring EntityChester G. Clark
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Current AssigneeLester L. Linquist, Ralph E. Belke
Sponsoring EntityLester L. Linquist, Ralph E. Belke
|Treatment for electroplating racks to avoid rack metallization|
Patent #US 9,809,899 B2
Current AssigneeMacdermid Acumen Incorporated
Sponsoring EntityMacdermid Acumen Incorporated
- 1. A rack for use in electroplating, said rack comprising:
one or more support arms, said one or more support arms having an axis; wherein said one or more support arms rotate around said axis; one or more clips affixed to said one or more support arms, each of said one or more clips further comprising a first prong; wherein said first prong is configured to contact the interior wall of a work piece at a single contact point; wherein said one or more clips rotate in conjunction with said one or more support arms when said one or more support arms rotate around said axis; and one or more first buoyant devices directly affixed to said one or more support arms, wherein said one or more first buoyant devices rotate in conjunction with said one or more support arms; and
wherein movement of said one or more first buoyant devices causes said one or more support arms rotate around said axis.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
This application claims priority to U.S. Provisional Patent Application No. 62/201,423, filed on Aug. 5, 2015, which is incorporated herein by reference in its entirety.
The Invention relates generally to electroplating equipment and processes. More specifically, the invention relates to assemblies which may be used in electroplating processes to further the immersion and plating of work pieces in the plating bath.
The technology of electroplating is well known. Electroplating or electro deposition involves the immersion of a cathode and anode in an electrolyte. With the application of a current to the anode, metal salts within the electrolyte are reduced at the electrolyte—cathode interface and plate out onto the cathode.
Electroplating is most commonly used to change the surface properties of a work piece. Physical properties such as strength, wear and abrasion resistance, resistance to ambient conditions such as temperature extremes and impact can all be affected by the deposition of adjunct metal coatings to the work piece. Other properties such as lubricity and corrosion resistance, may also be affected by electroplating. Electroplating is also commonly used to affect the aesthetic properties of a work piece through the application of a more preferred surface coating onto the object.
The literature is replete with electroplating processes and devices which have been used previously. Examples of devices and processes include those disclosed by Oliver in U.S. Pat. No. 1,533,805 as an electroplating rack which addresses the routine problem of hangers being coated and needing cleaning. Oliver discloses hangers which may be removed and replaced during cleaning so as to avoid down time in the plating process. Davis U.S. Pat. No. 2,484,079 discloses a hydraulically operated plating machine intended to avoid many of the concerns which arose with chain driven plating apparatus. Similar to Oliver, Belke, U.S. Pat. No. 2,820,757, discloses a plating rack assembly. The Belke plating rack is intent on maintaining low electrical resistance connections between the rack and the articles to be electroplated through assembly, plating, and disassembly. Henson, U.S. Pat. No. 2,898,285 also addresses the concern of errant metal deposits on the electroplating rack by the use conductive elements placed on the rack.
Novitsky, U.S. Pat. No. 3,314,877 discloses a plating and anodizing rack having a cylindrical shape. Chenevier, U.S. Pat. No. 3,607,707 also addresses the corrosivity of the plating process and the effect on the racks used therein. Fueki et al., U.S. Pat. No. 3,939,056 discloses an electroplating rack which is intended to reduce the amount of plating build up on the rack. The evident problem is that the buildup of deposits on the plating rack is a waste of material, and inevitably takes the rack out of service to be cleaned. Without cleaning, plating will further erode the structural integrity of the rack over time.
Of the problems addressed in the technical field of electroplating, one concern is the consistent and thorough cleaning of the work piece prior to the plating process as well as consistent and thorough electro deposition during the plating process.
Work pieces come in many sizes, shapes and with many different points of detail, patterning and design. Depending on the purpose of the deposition, the plating coverage of the work piece can be critical. Further coverage of the work piece is not always easy or intuitive.
Work pieces with a high level of detail can offer concerns over the permeation of the plating bath into the points of detail. Work pieces having walls that extend outwardly from a closed bottom (for example having the shape of a cup), are also one further design that may present problems with cleaning and plating.
Conventional plating processes such as those disclosed above, place the work piece in the plating bath through an up and down motion. While extended time in the bath can overcome certain concerns of the bath permeating the definition of the work piece, practical limitations abound.
Examples of recent attempts at plating racks and assemblies include Patent Application Publication US 2002/0179438 which discloses a plating clamp assembly intended to selectively clamp a work piece and thus allow for selective coating of the work piece.
U.S. Pat. No. 7,850,830 discloses a plating rack having a cylindrical central portion which moves through mechanical action to, in turn, move work pieces through the plating bath.
Patent Application Publication US 2014/0076720 discloses an electro polishing fixture with a lever arm intended to maintain electrical connection and reposition.
Seemingly self-evident, cleaning and then plating is easier to discuss than do. The submersion of a fixed piece in a stationary position on conventional racks does not always allow for penetration of cleaning solution into cracks and crevices of the work piece. Varying patterns as well as shapes and designs present concerns that often leave individual work pieces either partially cleaned or partially plated, making the work piece less than acceptable for application into the intended environment of use.
Despite these advances, further work needs to be done to reposition or reorient work pieces in the plating bath to accommodate penetration or permeation of the bath into the definition of the work piece. Thus there is a need to solve these and other problems found in the art.
In accordance with one aspect of the invention, there is provided a rack for use in electroplating; one or more support arms, wherein the one or more support arms rotate around the axis of the one or more support arms; one or more clips affixed to the one or more support arms, wherein the one or more clips moves rotationally when the one or more one or more support arms rotate; and a device affixed to the one or more support arms, wherein the device causes said one or more support arms to rotate.
In accordance with a further aspect of the invention, there is provided a rack for supporting work pieces during electroplating having a frame with respective first and second side portions and top and bottom portions, the first and second sides attached to each other through top and bottom portions; one or more support arms extending between the frame first and second sides, the one or more support arms affixed to the frame to allow rotational movement of the one or more support arms; one or more clips affixed to the support arms, the one or more clips configured to hold a work piece; and a buoyant device affixed to one or more support arms.
The invention is a rack for submersing work pieces or parts into plating baths. The design of the rack provides definite economies and efficiencies in the overall plating process. As noted in the literature cited above, optimal plating comes with low contamination between baths, cooler temperatures, and higher current densities.
The use of clips used for affixing the work pieces to be plated to the frame, the clips having a certain composition and thickness, allows for faster and higher quality plating due to higher current densities. The combined effect of the pattern of the clips and the articulating—pivoting—motion of the support arms also allows for more effective cleaning of the individual work pieces prior to plating and more effective plating during the actual processing. The articulating motion of the support arms also allows for better draining of the work pieces after submersion.
By combining articulation of the support arms and the provision of better contact points through the clips described herein, the plating rack of the invention heightens conductivity and in turn, lowers energy thereby increasing the efficiency of cleaning and plating processes.
Turning to the Figures wherein like parts are designated with like numerals throughout several views, an electroplating rack 10 is shown in its environment of use in
As noted above, the electroplating rack generally comprises an exterior frame. The frame functions to support support arms 26 which, in turn, hold parts 50 to be anodized (see
The first 34 and second 36 sides may generally be configured to attach the support arms 26 to the frame. The frame also preferably facilitates the plating process. The top portion of the rack generally includes hangers 14 attached to a conveyor 16 which will allow the rack to be submersed and raised in the series of baths used for the plating process. The bottom of the rack 32 may be closed with a bottom portion or left open. One of skill in the art having read this specification will appreciate that plating processes generally proceed through a number of baths 20, as shown in
Alternatively, the first 34 and second 36 sides may be supported by intermediate supports placed intermittently down the length of, and between, the first 34 and second 36 sides. In a further alternative embodiment, the first 34 and second 36 sides may be affixed to the support arms in a manner which allows full use of the rack 10 of the invention but without any further supporting structure between the first 34 and second 36 sides. To this end, in this embodiment of the invention, the support arms 26 are suspended between the first and second sides in a manner which allows for the hanging of the rack from the conveyor as it proceeds through the plating process and for free rotation of the support arms during the cleaning and plating process.
The support arms 26 function to hold and support the work pieces intended to be plated during the plating process. In accordance with the invention, the support arms are configured to rotate as the rack is submersed in the individual plating baths 20, as shown in
Further, the support areas 26 are suspended between the rack first 34 and second 36 sides to swivel or articulate allowing movement of the clips 24 and, in turn, the work pieces 50. Preferably, the movement is rotational around the axes of the support arms 26. One manner of suspending or attaching support arms 26 to the rack 10 of the invention is by bolting the support arms 26 with one or more bolts 38 to hole 39 found on rack first 34 and second 36 sides, as shown in
Preferably, a bolt 38 is inserted such that the head of a bolt 38 is not flush against hole 39 or nut 41. Rather, in a preferred embodiment a portion of the shank or thread of the bolt 38 is left exposed. This allows the support arms 26 to move laterally with respect to the rack first 34 and second 36 sides, allowing better stacking where multiple support arms 26 are utilized.
We have found that throughout the plating process, a critical aspect to the process is cleaning and then plating the individual parts as intended. Important to cleaning is completely contacting the internal and external surfaces of the individual work pieces with cleaning solution to remove any contaminating matter from these exterior and interior surfaces. This prevents the buildup of corrosion due to the combined effect of built up salts and other contaminants on the raw work piece (prior to plating) and contact with the various constituents of the baths 20 during the plating process. Important to plating is properly plating the individual work piece so that the entirety of the work piece is coated.
In accordance with the invention, the support arms 26 comprise clips 24 affixed thereto and extending from one side of the rack 10. The rack 10 also comprises a buoyant device 28 which creates movement or articulation also attached to the support arm 26 and extending from the support arm 26, as shown in
Placement of the work piece on the clips has traditionally been through attachment to an outer surface on the work piece, Attachment to the outer surface often resulted in areas on the outer or exterior surface which were left unplated. Other concerns raised by clipping the exterior of the work piece 50 is a loss of conductivity and having parts fall off of the rack into the bath 20.
In accordance with the invention the clips 24 are configured to fit within the inner diameter of the work piece 50 and thereby leave the exterior surface of the work piece 50 untouched and fully plated, as shown in
The clips 24 may comprise any composition which allows conductive plating to take place on the work piece 50. Representative compositions include phosphor bronze, steel, hardened steel, and stainless steel 300 series or non-magnetic stainless steel. The thickness of the clips may range from 0.050 inches to 0.250 inches and preferably 0.088 inches to 0.098 inches. One preferred material is stainless steel 300 (magnetic) in a thickness of about 0.093 inches. Generally, this thickness in the clips is preferred as it provides support for the work pieces 50 and better conductivity during plating.
Also attached to the support arm 26 is a buoyant device 28 which creates rotational movement or articulation in the support arm 26. The movement is rotational around the axis of attachment 40 of the support arm 26, such that the buoyant device 28, support arm 26 and work piece 50 form a lever. Any number of devices which will create this movement may be used in accordance with the invention. Preferably a structure which is buoyant in the various cleaning and plating baths 20 may be used. One preferred structure that we have found useful is a polymeric plastic cylinder buoyant device 28 filled with a gas such as air, nitrogen or the like, as shown in
As can be seen in
As the rack of the invention is removed from the individual baths, the force of the fluid against the buoyant device 28 forces the buoyant device 28 down and, in turn, the clips 24 up. This action, in turn, moves the work piece once again. With this reorientation, the work piece 50 once again is exposed at different angles to the fluid of the bath 20 thus allowing an additional opportunity for exposure of the surfaces of the work piece 50 to the bath fluid.
In certain embodiments, it is desirable for the support arm 26 to have freedom of movement in one bath, and to be restrained in other baths. As such a locking bar 52 as disclosed in
We have found that the weight and length of the work piece 50 affects the ability of the buoyant device 28 to move the support arm 26 up and down in the plating bath 20. Specifically, a work piece 50 which is extraordinarily heavy or long may change the center of gravity of the lever formed by the buoyant device 28, support arm 26 and work piece 50, such that the work piece 50 is not adequately exposed to the fluid of plating bath 20. In such instances one or more additional buoyant devices 29 may be attached to the buoyant device 28 to correct the center of gravity. Like buoyant device 28, additional buoyant device 29 is preferably a polymeric plastic cylinder. Further, in a preferred embodiment the additional buoyant device 29 has dimensions of 15.5 inches by 1 inch. Additionally, in a preferred embodiment, the ends of additional buoyant device 29 may have a dome shape, like buoyant device 28. In a more preferred embodiment, the ends of additional buoyant device 29 may have a truncated dome shape. An additional buoyant device 29 may be attached to buoyant device 28 by way of a dual C-clamp 54 as depicted in
In certain embodiments of the present invention the fluid of the plating bath 20 is agitated to allow for better plating of the work piece 50. In such instances the agitation may cause the rack 10, when lowered into the plating bath 20, to be pushed against the wall of the plating bath 20. Such movement is undesirable as it may prevent the support arm 26 from moving properly, resulting in a work piece 50 that is not adequately plated. To prevent such movement, one or more weights 56 may be removably attached to the bottom of rack 10, as shown in
Although the invention has been described and illustrated with respect to the exemplary embodiments thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and additions may be made therein and thereto, without departing from the spirit and scope of the claimed invention.