Patent Publication Number: US-2010112298-A1

Title: Method for making housing and housing thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is one of the two related co-pending U.S. patent applications listed below. All listed applications have the same assignee. The disclosure of each of the listed applications is incorporated by reference into all the other listed applications. 
     
       
         
           
               
               
               
             
               
                   
               
               
                 Attorney 
                   
                   
               
               
                 Docket No. 
                 Title 
                 Inventors 
               
               
                   
               
             
            
               
                 US23419 
                 HOUSING AND METHOD FOR 
                 FENG-YUEN 
               
               
                   
                 MAKING THE SAME 
                 DAI et al. 
               
               
                 US23422 
                 METHOD FOR MAKING HOUSING 
                 FENG-YUEN 
               
               
                   
                 AND HOUSING THEREOF 
                 DAI et al. 
               
               
                   
               
            
           
         
       
     
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to method for making housings and housings thereof. 
     2. Description of Related Art 
     Micro-arc oxidation is a surface treatment process that oxidizes a metal surface to form a micro-arc oxide film. Micro-arc oxide films have similar appearance and physical properties as ceramics and possess high rigidity. However, the micro-arc oxide film can only present matte appearance and cannot decorate the housing with more attractive gloss. 
     Therefore, there is room for improvement within the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
       Many aspects of the housing can be better understood with reference to the following drawing. The components in the drawing are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the housing. 
       The FIGURE is a cross-sectional view of an exemplary embodiment of a housing. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the FIGURE, in an exemplary embodiment, a method for making a housing  10  may generally comprise the following steps: providing a substrate; etching the substrate to form a plurality of grooves on one surface of the substrate; micro-arc oxidizing the substrate to form a micro-arc oxide film in the grooves and on the surface of the substrate; and polishing the micro-arc oxide film formed on the surface of the substrate. Each step is described in more detail below. 
     A substrate  11  is provided. The substrate  11  is made of metal selected from a group consisting of aluminum, aluminum alloy, magnesium, magnesium alloy, titanium, and titanium alloy. 
     The substrate  11  is etched to form a plurality of grooves  115 . These grooves  115  define a predetermined pattern. The pattern may be a logo or a decorative pattern. The etching step may be carried out by chemical eroding or CNC numerical control machine engraving the surface of the substrate  11 . 
     The substrate  11  is micro-arc oxidized to form a micro-arc oxide film  13  on the surface of the grooves  115  and the substrate  11 . The oxidation process may comprise the following steps: 
     The substrate  11  is firstly de-dusted in an alkaline solution for about 10 minutes. Dust adhering to the substrate  11  is removed by the de-dusting process. After the de-dusting process, the substrate  11  is rinsed in water. 
     The substrate  11  is then micro-arc oxidized in an electrolyte contained in a stainless steel tank to form the micro-arc oxide film  13  on the surface of the substrate  11  and in the grooves  115 . The electrolyte includes at least one of phosphate salt, borate salt, silicate salt, aluminate salt, and alkali metal hydroxide. The electrolyte may further include at least one of tungstate salt, vanadate salt, ammonium metavanadate, sulfate salt, sodium fluoride, cobalt acetic, sorbitol, and glycerol. The pH of the electrolyte may be in a range of about 10.5-12.5. The temperature of the electrolyte is about 20-50° C. During the oxidation process, a bidirectional voltage pulse including a forward pulse and a reverse pulse is applied to the substrate  11  and the stainless steel tank for about 30-180 minutes to develop the micro-arc oxide film  13 . The pulse width of the bidirectional pulse is about 1000-10000 microseconds (μs). The pulse interval of the bidirectional pulse is about 300-2000 μs. During the forward pulse, the voltage gradually grows to a positive voltage in a range of about 450-650 volts. During the reverse pulse, the voltage gradually grows to a negative voltage in a range of about −30˜−200 volts. 
     After the micro-arc oxidation process, the substrate  11  having the micro-arc oxide film  13  is rinsed in water and baked in an oven. 
     After the oxidation process, the micro-arc oxide film  13  formed on the surface of the substrate  11  is mechanically polished to present a glossy appearance. The polishing process may comprise a rough polishing step, a secondary polishing step, and a precise polishing step. The rough polishing step may be carried out by a copper polishing disk for about 4-7 minutes. The secondary polishing step may be carried out by a resin polishing disk for about 1-4 minutes. The precise polishing step may be carried out by a polyurethane polishing disk for about 0.5-1.5 minutes. The micro-arc oxide film  13  formed on the surface of the grooves  115  is not polished and present a matte appearance. 
     The micro-arc oxide film  13  undergoes a sealing process to seal the micro pores of the oxide film  13  to prevent the film  13  from being contaminated. The sealing agent used in the sealing process may be a mixture of silicone resin and a diluting agent. The silicone resin may advantageously be methyl hydrogen silicone fluid. The diluting agent may be organic solvent selected from a group consisting of isopropyl alcohol, toluene, xylene and acetone. The mass ratio between the silicone resin and the organic solvent is about 1˜2:0.5˜1.5. The sealing process is carried out by uniformly daubing the micro-arc oxide film  13  with the sealing agent to make some of the sealing agent be adsorbed into the micro pores of the oxide film  13 . After the sealing process, the film  13  is cleaned by using a dry clean wiper to remove the extra sealing agent on the film  13  that was not adsorbed. After the cleaning process, the film  13  is baked in an oven. 
     Referring to the FIGURE, in an exemplary embodiment, the housing  10  made by the above mentioned method includes a substrate  11  and a micro-arc oxide film  13  formed on the substrate  11 . 
     The substrate  11  includes a first surface  111  and a second surface  113  on an opposite site to the first surface  111 . The second surface  113  is defined a plurality of grooves  115  therein. The micro-arc oxide film  13  is formed on the second surface  113  and in the grooves  115 . These grooves  115  define a predetermined pattern of the housing  10 . The pattern may be a logo or a decorative pattern. The grooves  115  may be formed by chemical eroding or CNC numerical control machine engraving the substrate  11 . The substrate  11  is made of metal selected from a group consisting of aluminum, aluminum alloy, magnesium, magnesium alloy, titanium and titanium alloy. 
     The micro-arc oxide film  13  formed in the grooves  115  forms a hollowed plane  131 , and the oxide film  13  formed on the substrate  11  forms a raised plane  133 . The raised plane  133  is mechanically polished to present a glossy appearance. The hollowed plane  131  is not polished to present a matte surface like the micro-arc oxide film  13 . 
     The exemplary housing  10  forms a raised plane  133  to give a glossy appearance and a hollowed plane  131  to give a matte appearance which, for example, produce a strong or subtle contrast appearance to improve the appearance attraction of the housing  10 . 
     It should be understood, however, that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, together with details of functions of the embodiments, the disclosure is illustrative only, and changes may be made in detail within the principles of the disclosure to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.