The present disclosure relates generally to improved aesthetics for work pieces, including by a method of electroplating. More specifically, the present disclosure relates to a method for creating multiple electrical current pathways on a work piece to allow for the presence of multiple separate finishes on a single plastic work piece.
Plated decorative chrome finishes have long been available for various products in the automotive, appliance, consumer electronics, and household application industries. Variations in the deposition methods, processing conditions, and solution makeup of the various types of metals have subsequently resulted in aesthetic variations in the final product. These variations in processing, chemical, and deposition techniques are able to generate different color metal finishes, lower gloss levels, and less distinction of image (DOI) in the metal finish of work pieces all with an eye to improving aesthetics. Examples of these finishes include but are not limited to Bright Chrome, Black Nickel, Black Chrome, and the like. Another exemplary finish that has been employed is Satin Chrome, which involves varying the reflectivity of the underlying metal layer such as by creating more pits in the substrate surface. Varying the degree of reflectivity allows for many different types of metal finishes. Often, these variations are combined with a bright chromium finish in assemblies to 1) complement each other and 2) bring more aesthetic appeal to the final product.
A known method of finishing work pieces to provide a final product that has multiple distinct surface finishes includes utilizing work piece assemblies that are made up of multiple components, each having a different metal finish and which are assembled to form the final product. This practice, while effective, results in multiple operations and multiple sets of tooling which adds significant cost to the final product.
Another known method of finishing work pieces to provide a final product that has multiple distinct surface finishes includes applying bright and satin-like finishing to the surface of the work piece with masking and pre or post surface treatments using abrasive grains such as iron powder, glass powder, silicon oxide, alumina and the like. Molded in texture or surface effects have also been employed to create variation in the metal finish of the work piece by selectively incorporating the texture or surface finish into a portion of the work piece prior to application of a metal finish. However, when such work pieces, which include one section employing these surface effects and another part without these effects, are both subjected to electroplating, the leveling characteristic of the electroplated layer on these two sections does not create the visual effect of two distinct metal surface finishes as desired. Also, the pre and post surface treatments are costly and require an additional operation.
Vacuum metallization and chemical vapor deposition techniques are able to achieve a final product that has segments with different finishes, but are very costly and limited from a performance standpoint in many environments because of the thin layer of metal that results from these techniques. Additionally, physical vapor deposition coatings must include an organic coating thereover to protect the deposited metal layer. This additional step increases labor costs and creates an “orange peel” look due to the fact that the organic coating is not completely smooth.
Another method of creating two distinct surface effects on a work piece includes masking and painting using tinted basecoats and clear coats. Although this method creates the desired effect, it disadvantageously requires an additional painting operation which adds cost to the final product.
In view of the above, there remains a need for improved methods of treating work pieces that provide for a final product that includes more than one surface finish on a single work piece. More specifically, there remains a need for a method which offers more degrees of flexibility to designers and manufacturers with regards to its aesthetic effects while reducing the overall part and manufacturing costs by eliminating secondary operations.
A method for plating a plastic work piece using a power source having a positive terminal and a negative terminal is provided. The method includes applying an electroless layer of material to the work piece using an electroless plating process. The positive terminal of the power source may be connected to a first anode and the negative terminal of the power source may be connected to the work piece. The work piece can then be immersed in a first aqueous solution that contains the first anode. The first anode may then be positively charged and the work piece may be negatively charged to cause metal ions in the first aqueous solution to be passed onto the electroless layer of the work piece.
The method can further include creating at least one barrier in electrical conductivity in the work piece prior to the step of immersing the work piece in a first aqueous solution to divide the work piece into at least a first segment and a second segment which are substantially electrically insulated from one another.
The negative terminal of the power source can also be connected to the second segment of the work piece. The method may also include immersing the work piece in a second aqueous solution that contains a second anode. Once the work piece is immersed in the second aqueous solution, the second anode can be positively charged and a second negative charge may be applied to the second segment of the work piece to cause metal ions from the second aqueous solution to be passed onto the electroless layer of only the second section of the work piece to form a second electroplated layer on the second segment of the work piece.
It is therefore an aspect of the present disclosure to provide a method for plating a work piece with multiple surface finishes. The method eliminates the need for costly secondary operations to finish the work piece since creating the barrier in electrical conductivity and respectively electroplating the first and second segments of the work piece may be done in an inexpensive and simple process.
Other aspects of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a method is generally shown for plating a work piece 100 using a power source 102 (e.g., a battery) having a positive terminal 104 and a negative terminal 106. It will be appreciated that a variety of suitable power sources may be employed.
According to an aspect, as exemplarily shown in
According to an aspect, the method can also include creating a barrier 114, 214, 314 in electrical conductivity in the work piece 100 to divide the work piece 100 into a first segment 116 and a second segment 118, with the first and second segments 116, 118 substantially electrically insulated from one another, as generally indicated by reference number 12. As a result, a current may flow through each respective first and second segment 116, 118 without flowing through the other. As shown in
According to an aspect and as exemplarily shown in
According to another aspect as exemplarily shown in
According to a further aspect as exemplarily shown in
It should be appreciated that any combination of the aforementioned methods may be used to create the barrier 314 in electrical conductivity. According to an aspect, the barrier 314 on the front surface can be formed utilizing one method and the barrier 314′ on the back surface can be formed utilizing another method. For example, the barrier 314 on the front surface can be formed via an injection molding method utilizing a material that is resistant to plating and the barrier 314′ on the back surface can be formed utilizing a spray resist coating. It will be appreciated that a variety of other suitable ways may be employed to create barriers to electrical conductivity.
According to an aspect, as shown
According to aspect, the method proceeds with connecting the negative terminal 106 of the power source 102 to a first point of contact 123 on the first segment 116 of the work piece 100, as generally indicated by reference number 16. The work piece 100 may then be immersed in the first aqueous plating solution 122 which may contain metal salts and the first anode 120, as generally indicated by reference number 20. After the work piece 100 has been immersed in the first aqueous solution 122, the method can proceed with 20 positively charging the first anode 120 and negatively charging the first segment 116 of the work piece 100 to cause the metal ions in the first aqueous solution 122, to be reduced to their metallic state at the solution interface of the first segment 116. A layer of metal may then form on the first segment 116 because it is the only location on the work piece 100 that has a supply of electrons to reduce the metal salts to their respective metal state (i.e., Cu2++2e→Cu0). Because there is no supply of electrons on the second segment 118 (since it is electrically isolated), metal ions in the first aqueous solution 122 cannot be reduced to their metallic state.
According to another aspect, as shown in
According to a further aspect, the method can then proceed with connecting the negative terminal 106 of the power source 102 to a second point of contact 130 on the second segment 118 of the work piece 100, as generally indicated by reference number 24. The work piece 100 may then be immersed in the second aqueous solution 128 which contains the second anode 126, as generally indicated by reference number 25. After the work piece 100 has been immersed in the second aqueous solution 128, the method can continue with positively charging the second anode 126 and negatively charging the second segment 118 of the work piece 100 to cause metal ions from the second plating solution 126 to be passed onto the electroless layer 108 on the second segment 118 of the work piece 100 to form a second electroplated layer 132 on the second segment 118, as generally indicated by reference number 26. It should be appreciated that a metal layer only forms on the second segment 118 of the work piece 100 because the first and second segments 116, 118 are electrically insulated from one another by the barrier 114, 214, 314.
As a result of the aforementioned steps, after the second electroplated layer 132 of metal has been formed on the second segment 118 of the work piece 100, the first and second segments 116, 118 have different metallic finishes. It should further be appreciated that additional barriers 114, 214, 314 in conductivity could be made on the work piece 100 to provide additional segments that are electrically insulated from one another. Such additional segments could be electroplated in accordance with the aforementioned steps to provide for more than two segments of the work piece 100 that have different metallic finishes.
According to a still further aspect, to improve adherence of the first and second electroplated layers 124, 132 to the work piece 100 and to improve the structural properties of the work piece 100, an intermediate electrolytic layer of copper from an acid copper plating solution may be applied to both the first and second segments 116, 118 after the electroless layer of material 108 is applied to the work piece 100, and prior to electroplating the first and second electroplated layers 124, 132 as described above. Applying this intermediate layer can build the metal thickness to a level that is sufficient to carry the current for electroplating of subsequent metal layers. After the intermediate copper layer has been electrodeposited to a sufficient thickness, an intermediate layer of sulfur-free nickel may be electroplated onto the copper surface to protect the copper from corrosion on all electrical pathways on the part. After the deposition of the intermediate layer of sulfur-free nickel is electroplated on the work piece, there can be a significant amount of metal to carry current, and the copper layer is protected. Therefore, the work piece 100 can be immersed in any suitable plating solution and electroplated as described above to provide the first and second electroplated layers 124, 132 to achieve the desired finishing effect. It should be appreciated that the method could alternatively proceed without these steps and other materials could be used in these steps in place of those described. It will additionally be appreciated that intermediate layers consisting of different materials could be applied to the first and second segments 116, 118 to provide different appearances for the work piece 100.
According to a further aspect of the present disclosure, after a barrier 114, 214, 314 is created as described above to electrically isolate multiple sections of a work piece 100, an electrophoretic coating may be selectively deposited on at least one of the sections of the work piece 100 in order to create different aesthetic affects. It will be appreciated that the deposition of the electrophoretic coating may occur in connection with the deposition of one or more different metal layers as discussed above. It will be appreciated that different electrophoretic coatings may be selectively deposited in the same fashion discussed above such that one electrophoretic coating may be applied to one section of a part without it being applied to another section of the part.
According to a still further aspect of the present disclosure, as the barriers can be formed on both the front side 140 and the back side 142 of the work piece 100, metal layers are not deposited thereon, as discussed above. As shown in the Figures, a light source 150, 250, 350 may be disposed behind the work piece 100 and positioned to emit light into the barriers to provide a backlighting effect, as shown, to enhance aesthetics. It will be appreciated that the use of a transparent or translucent material at the barrier can assist with this effect, although non-translucent or non-transparent materials may also be employed. Alternatively, the work piece 100 may be formed of resins of different colors to provide additional aesthetic affects.
According to an aspect, the first circuit 406 can include a first power source 410, a first cathode 412 and a first connector bushing 414. The first power source 410 can provide power to the first cathode 412 to charge at least a portion of one or more work pieces. The first power source 410 may be in communication with the first cathode 412 via the first connector bushing 414. According to a further aspect, the first cathode 412 may be integrated into the plating rack 402. According to a still further aspect, the second circuit 408 can include a second power source 416, a second cathode 418, and a second connector bushing 420. The second power source 416 can provide power to the second cathode 418 to charge at least a portion of one or more work pieces. The second power source 416 may be in communication with the second cathode 418 via the second connector bushing 420. The second cathode 418 may also be integrated into the plating rack 402.
According to an aspect, each of the circuits 406, 408 may be electrically insulated from each other. Additionally, each of the circuits 406, 408 can connect to separate power sources such that each of the circuits can be activated individually or simultaneously as desired. The use of separate circuits allows for the plating of different metals on a single work piece. According to a further aspect, the plating rack 402 may be coated with a plate resistant coating to prevent rack plate-up as well as rack damage. The plate resistant coating may be Platisol, however, a variety of other suitable coatings may be employed.
It will also be appreciated that an auxiliary anode may also be incorporated into the tooling to assist in the deposition of metal in areas where the electrical current density is limited, such as recessed areas.
Obviously, many modifications and variations of the present disclosure are possible in light of the above teachings and may be practiced otherwise than as specifically described while within the scope of the appended claims. These antecedent recitations should be interpreted to cover any combination in which the inventive novelty exercises its utility. The use of the word “said” in the apparatus claims refers to an antecedent that is a positive recitation meant to be included in the coverage of the claims whereas the word “the” precedes a word not meant to be included in the coverage of the claims.
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