Patent Publication Number: US-2006005390-A1

Title: Method of coating hub and electroplating a portion thereof

Description:
FIELD OF THE INVENTION  
      The present invention relates to the manufacturing processes of coating and electroplating and more particularly to a process of coating a hub of an automobile wheel and electroplating a portion thereof.  
     BACKGROUND OF THE INVENTION  
      Conventionally, hub of an automobile wheel is made of aluminum alloy for safety and aesthetic purposes. Also, the hub is either coated with epoxy or electroplated. As far as the present inventor is aware, there is no disclosure of coating the hub and electroplating a portion thereof in a manufacturing process.  
     SUMMARY OF THE INVENTION  
      It is an object of the present invention to provide a process of manufacturing a wheel hub, comprising the steps of (a) coating a blank made of aluminum alloy on a surface of the blank; (b) removing a portion of the blank for exposing the aluminum alloy of the blank to be electroplated; (c) polishing the exposed portion of the blank; (d) removing wax and oil stains from the surface of the blank; (e) sequentially electroplating nickel and copper on the exposed portion of the blank; (f) polishing the copper layer on the exposed portion of the blank; (g) removing wax and oil stains from the surface of the blank; (h) sequentially electroplating a plurality of nickel layers having different concentrations of sulfur on the copper layer; and (i) electroplating chrome on the nickel layers for producing the wheel hub.  
      In one aspect of the present invention, the step (c) comprises the sub-step of polishing corners or grooves on the exposed portion of the blank; the step (d) comprises the sub-steps of submerging the blank in a first solution, removing wax deposited on the surface of-the blank, cleaning the blank with water, submerging the blank in a second solution, and cleaning the blank with water; the step (e) comprises the sub-steps of submerging the blank in a third solution having a weak acid for etching out an oxidized layer on the exposed portion of the blank, cleaning the blank with water, removing Al 2 O 3  from the exposed portion of the blank by a solution prepared by mixing nitric acid, sulfuric acid, phosphoric acid, and detergent, cleaning the blank with water, depositing a layer of zinc on the exposed portion of the blank by submerging the blank in a fourth solution, removing zinc and Al 2 O 3  from the exposed portion of the blank by submerging in a fifth solution, cleaning the blank with water, depositing a layer of zinc on the exposed portion of the blank, cleaning the blank with water, electroplating liquid nickel on the exposed portion of the blank, cleaning the blank with water, activating the exposed portion of the blank in a first predetermined acid solution, cleaning the blank with water, electroplating copper on the exposed portion of the blank, cleaning the blank with water, passivating the exposed portion of the blank coated with copper in a second predetermined acid solution, and cleaning the blank with water; the step (f) comprises the sub-steps of spraying copper on the corners or the grooves on the exposed portion of the blank, smoothing the same, and polishing the same; the step (g) comprises the sub-steps of submerging the blank in sixth solution for removing copper, cleaning the blank with water, submerging the blank in a seventh solution for removing oil stains from the exposed portion of the blank, cleaning the blank with water, neutralizing acid substance on the copper layer of the exposed portion of the blank, cleaning the blank with water, depositing a zinc layer on the exposed portion of the blank, and cleaning the blank with water; the step (h) comprises the sub-steps of removing oil stains from the exposed portion of the blank by electrolysis, cleaning the blank with water, activating the copper layer of the blank in a third predetermined acid solution, cleaning the blank with water, electroplating liquid nickel of low brightness on the exposed portion of the blank, electroplating liquid nickel having a high concentration of sulfur on the exposed portion of the blank, electroplating liquid nickel of high brightness on the exposed portion of the blank, electroplating liquid nickel of high concentration on the exposed portion of the blank, and cleaning the blank with water; and the step (i) comprises the sub-steps of installing an anode, electrolyzing the blank, cleaning the blank with water, activating the nickel layer on the exposed portion of the blank by means of chromic acid, electroplating a layer of chrome on the exposed portion of the blank, cleaning the blank with water, reducing Cl 6  ions in the electrolyte as Cl 3  ions by adding NaHSO 3  therein, cleaning the blank with water, removing the anode, and cleaning the blank with water.  
      The above and other objects, features and advantages of the present invention will become apparent from the following detailed description. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      A process of coating a wheel hub made of aluminum alloy and electroplating a portion thereof in accordance with the invention comprises the following steps. Step 1 includes the sub-steps of smoothing uneven surface areas of a hub blank made of aluminum alloy by means of sandpapers, spraying sand on a surface of the blank for about 9 seconds for decreasing the number of holes thereon, mixing hardener with fine powder in a ratio of 2 to 100, and filling holes on the surface of the blank with the mixed hardener for eliminating large holes and/or recesses.  
      Step 2 includes the sub-steps of drying the blank, smoothing the surface of the blank by means of sandpaper or the like, cleaning the surface of the blank with water of 30° C. to 40° C., drying the surface of the blank and removing dirt from the surface of the blank by means of a fan or the like, spraying a preliminary coat of paint on the surface of the blank, and drying the surface of the blank for adhering the preliminary coat of paint onto the surface of the blank in about 198° C.  
      Step 3 includes polishing the surface of the blank with a number of sandpapers of different rough degrees and a polishing machine.  
      Step 4 includes the sub-steps of cleaning the surface of the blank with water, drying the surface of the blank by means of a fan, spraying a coat of first paint on the surface of the blank, spraying a coat of second different paint on the surface of the blank, drying the surface of the blank for about 40 minutes in about 170° C. for adhering, spraying a coat of third different paint (e.g., antioxidant) on the surface of the blank, and drying the surface of the blank in about 160° C.  
      Step 5 includes removing a portion (e.g., flat areas on outer and inner surfaces) of the blank by shaving the surface of the blank for exposing the aluminum alloy substance of the blank.  
      Step 6 includes polishing corners, grooves, or the like on the exposed portion of the blank.  
      Step 7 includes the sub-steps of submerging the blank in BCR solution available from Ameter Corporation, removing wax deposited on the surface of the blank, cleaning the surface of the blank with water, submerging the blank in No. 152 solution available from Ameter Corporation, and cleaning the surface of the blank with water.  
      Step 8 includes the sub-steps of submerging the blank in U152 solution having a weak acid available from Ameter Corporation for etching out the oxidized layer on the exposed portion (i.e., aluminum portion) of the blank, cleaning the blank with water, removing Al 2 O 3  from the surface of the blank by a solution prepared by mixing nitric acid, sulfuric acid, phosphoric acid, and S solution (i.e., detergent) available from Ameter Corporation, cleaning the blank with water, depositing a layer of zinc on the surface of the blank by submerging the blank in W-B and W-E solutions available from Ameter Corporation, removing zinc and Al 2 O 3  from the surface of the blank by submerging in a solution having 50% nitric acid, cleaning the blank with water, depositing a layer of zinc on the surface of the blank again, cleaning the blank with water, electroplating nickel on the surface of the blank, cleaning the blank with water, activating the surface of the blank by means of a first predetermined acid solution, cleaning the blank with water, electroplating copper on the surface of  
      cleaning the blank with water, passivating the surface of the blank coated with copper by means of a second predetermined acid solution, and cleaning the blank with water in which nickel solution can be fed back for use.  
      Step 9 includes the sub-steps of spraying copper on corners, grooves, or the like on the exposed portion of the blank, smoothing the same, and polishing the same.  
      Step 10 includes the sub-steps of submerging the blank in SF-601 solution available from Sanford Corporation for removing copper, cleaning the blank with water, submerging the blank in 251 solution available from Ameter Corporation for removing oil stains from the surface of the blank, cleaning the blank with water, neutralizing acid substance on the copper layer of the surface of the blank, cleaning the blank with water, depositing a zinc layer on the surface of the blank, and cleaning the blank with water.  
      Step 11 includes the sub-steps of removing the oil stains from the surface of the blank by electrolysis, cleaning the blank with water, activating the copper layer of the blank by means of a first predetermined acid solution, cleaning the blank with water, electroplating liquid nickel of low brightness on the surface of the blank, electroplating liquid nickel having a high concentration of sulfur on the surface of the blank, electroplating liquid nickel of high brightness on the surface of the blank, electroplating liquid nickel of high concentration on the surface of the blank, recycling nickel solution, and cleaning the blank with water in which voltage difference between nickel solution of low brightness and nickel solution of high brightness is 130 mV, voltage difference between nickel solution having a high concentration of sulfur and nickel solution of low brightness is 20 mV, and voltage difference between nickel solution of high concentration and nickel solution of high brightness is 15 mV.  
      Step 12 includes the sub-steps of installing an anode, electrolyzing the blank, cleaning the blank with water, activating the nickel layer on the surface of the blank by means of chromic acid, electroplating a layer of chrome on the surface of the blank, cleaning the blank with water, reducing Cl 6  ions in the electrolyte as Cl 3  ions by adding NaHSO 3  therein, cleaning the blank with water, removing the anode, directing the chromic electrolyte to flow to a reservoir for future use, and cleaning the blank with water.  
      Step 13 includes packing the finished hub having electroplated flat areas on both the outer and the inner surfaces thereof and coated other areas.  
      While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.