Abstract:
An environment protection concerned method for manufacturing a heat sink comprises steps of: (a) putting a main material with a top into a die; (b) placing a heat transfer promoting material on the top of the main material, wherein the heat transfer promoting material has a thermal conductivity larger than that of the main material; and (c) forging the heat transfer promoting material and the main material to form a heat sink having a plurality of radiation fins.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is related to an environmental protection concerned method for manufacturing a heat sink, and more particularly for manufacturing a heat sink with a plurality of radiation fins.  
         BACKGROUND OF THE INVENTION  
         [0002]    The kind of heat sinks with a plurality of radiation fins, a base plate several times as large as the upper surface of the package of an electronic component like a CPU, and the central portion of the base plate of the heat sink made of a metal material with larger thermal conductivity than the main material of the heat sink are commonly used for the heat dissipations of electronic components nowadays. However, a heat sink to further enhance the heat dissipation of an electronic component like the CPU of a personal computer or a large-scaled integrated circuit is in need in order to cope with the trend of increasing heat generations of the electronic components due to the requirements such as an even higher processing speed of a personal computer or a much more compact size of a IC component. For example, the increasing of the clock frequency and the number of gates will surely increase the heat generations of the electronic components.  
           [0003]    An improved method for manufacturing the above mentioned heat sinks to enhance the heat dissipation was proposed by Kataoka (U.S. Pat. No. 6,367,152 B1).  
           [0004]    In Kataoka&#39;s method, a metal material with larger thermal conductivity is joining integrally with the main material of the heat sink as a workpiece and forging into a heat sink without the drawbacks of either the loss in heat transfer causing by the deformation of the metal plate or the deformation of the radiation fins causing by the pretreatment when joining the metal plate to the base plate of the heat sink by screwing or brazing respectively. The Kataoka&#39;s method includes the following steps: 1. nickel or tin plating on one surface or both surfaces of the two raw materials (For example: copper and aluminum); 2. brazing or soldering to join the two raw materials together into a workpiece; 3. putting the workpiece into the die; 4. forging work piece under the pressure to form a heat sink.  
           [0005]    Please refer to FIGS. 1 and 2. In FIG. 1, it is a schematic diagram showing a main material  1  and a heat transfer promoting material  2  with a higher thermal conductivity than the main material  1  are joining integrally through nickel or tin plating and brazing to form a workpiece  10  of the prior art of the present invention. In FIG. 2, it is a schematic diagram showing the workpiece  10  forging in a die  3  under pressure to form a semi-product of the heat sink  4  of the prior art of the present invention.  
           [0006]    However, during the nickel plating there will be heavy metal being released and bring a serious pollution into the water or the tin plating there will be lead or zinc particles contained in the plating material being released into the air which is harmful to the health of the workers during soldering process or anyone who is in the working area. This is a source of pollution and surely will cause the environmental protection concerns. Besides, the temperature of brazing is around 400° C., and there will be heavy metal particles contained in the brazing material being released into the air which is also harmful to the health of the workers of the brazing process or anyone who is in the working area. This is an even more hazardous source of environmental pollution. There are still other drawbacks like the high temperature of brazing will hurt the anodize surface forming in the plating process so as to hamper the quality of brazing, and will reduce the metal stress of the heat sink which will cause the bending of the radiation fins while assembling with other parts.  
           [0007]    Keep the drawbacks of the prior art in mind, and employ experiments and research full-heartily and persistently, an environmental protection concerned method for manufacturing heat sink is finally conceived by the applicant. The proposed method will not only solve the lead, zinc and heavy metal pollution problems but also decreasing the manufacturing costs and improving the quality of the heat sinks.  
         SUMMARY OF THE INVENTION  
         [0008]    It is therefore an object of the present invention to propose an environmental protection concerned method for manufacturing a heat sink with a plurality of radiation fins.  
           [0009]    According to the aspect of the present invention, the method for manufacturing a heat sink comprises steps of: (a) putting a main material with a top into a die; (b) placing a heat transfer promoting material on the top of the main material, wherein the heat transfer promoting material has a thermal conductivity larger than that of the main material; and (c) forging the heat transfer promoting material and the main material to form a heat sink having a plurality of radiation fins.  
           [0010]    Certainly, the main material has a plurality of positioners confining thereamong said heat transfer promoting material.  
           [0011]    Preferably, the positioners have a shape selected from a group consisting of walls, ribs, poles, pins, dowels, stops, and any combination thereof.  
           [0012]    Certainly, the positioners are part of the main material.  
           [0013]    Preferably, the heat transfer promoting material, the main material, and the positioners are manufactured into a desired shape by a process selected from a group consisting of pressing, extruding, die-casting, powder-forming, machining and any combination thereof.  
           [0014]    Preferably, the main material is larger than the heat transfer promoting material.  
           [0015]    Preferably, the step (b) of the proposed method further comprises steps of: (b1) overflowing a material of the main material to bind together with the heat transfer promoting material after being pushed under pressure; (b2) projecting the radiation fins from the main material through a plurality of holes of the die; (b3) causing the heat transfer promoting material to form the central part of the top surface of the heat sink and the main material to form the surrounding part of the top surface of the heat sink; (b4) removing the heat sink from the die; and (b5) cutting and grinding the top surface of the heat sink into the base plate of the heat sink. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a schematic diagram showing the workpiece of the prior art of the present invention;  
         [0017]    [0017]FIG. 2 is a schematic diagram showing the workpiece forging in a die under pressure to form a heat sink of the prior art of the present invention;  
         [0018]    [0018]FIG. 3 is a schematic diagram showing the main material with different shapes of poisitioners and the heat transfer promoting material;  
         [0019]    [0019]FIG. 4 is a schematic diagram showing the main material with a top is putting into the die;  
         [0020]    [0020]FIG. 5 is a schematic diagram showing the heat transfer promoting material is placing into the die on the top of the main material among positioners;  
         [0021]    [0021]FIG. 6 is a schematic diagram showing the heat transfer promoting material and main material are pushing under pressure to form a heat sink;  
         [0022]    [0022]FIG. 7 is a schematic diagram showing the semi-product of the heat sink is removing from the die;  
         [0023]    [0023]FIG. 8 is a schematic diagram showing the semi-products of the heat sink; and  
         [0024]    [0024]FIG. 9 is a schematic diagram showing the final-products of the heat sink. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    Please refer to FIG. 3, which is a schematic diagram showing two preferred embodiments of the main material  1  and the heat transfer promoting material  2  before putting into a die for manufacturing the heat sinks. In FIG. 3, a poisitioner  11  is in a shape selected from a group of walls  111 , ribs  112 , poles  113 , pins  114 , dowels  115 , stops  116  and any combination thereof. Each positioner  11  is on the top surface of the main material and is part of the main material  1 . A main material  1  is preferably larger than a heat transfer promoting material  2 . The heat transfer promoting material  2  (For example: copper) has higher heat transfer conductivity than the main material  1  (For example: aluminum).  
         [0026]    Please refer to FIG. 4, which is a schematic diagram showing a main material  1  with poisitioners  11  is putting into a die  3  where the force die part  31  used to press the main material  1  and the heat transfer promoting material  2  has a pushing head  311  with a plurality of grooves  3111  in dove-tail shapes and the forming die part  32  of the die  3  has a receiving recess  321  where the main material  1  is received. The receiving recess  321  has a bottom surface  3211  with a plurality of holes  3212  for projecting the radiation fins of the heat sinks.  
         [0027]    Please refer to FIG. 5, which is a schematic diagram showing the heat transfer promoting material  2  is placing into the die on the top of the main material  1  among positioners  11 .  
         [0028]    Please refer to FIG. 6, which is a schematic diagram showing the heat transfer promoting material  2  and main material  1  are pushing under pressure to form a semi-product of heat sink  4 . The size of the pushing head  311  of the upper part  31  of the die  3  is smaller than the main material  1 . Firstly, when the heat transfer promoting material  2  and main material  1  are pushing under pressure to form a semi-product of the heat sink  4 , the main material  1  will overflow and bind with the heat transfer promoting material  2  intimately due to the tremendous pressure upon the main material  1  and heat transfer promoting material  2  in the forming die part  32 . Secondly, the heat transfer promoting material  2  will gap-fill into the dove-tail shaped grooves  3111 . Thirdly, the main material  1  will be projected to form the radiation fins  41  of the semi-product of the heat sink  4  through the plurality of holes  3212  of the forming die part  32 .  
         [0029]    Please refer to FIG. 7, which is a schematic diagram showing the semi-product of the heat sink  4  is removing from the die  3 . Due to the dove-tale shaped grooves  3111  of the pushing head  311 , the semi-product of the heat sink  4  will be un-separated with the force die part  31  while the force die part  31  is moving upward. When the force die part  31  is rising up, the semi-product of the heat sink  4  will be brought up as well. The worker can remove the semi-product of the heat sink  4  from the die  3  along the horizontal direction of the dove-tail shaped grooves  3111  of the pushing head  311 .  
         [0030]    Please refer to FIG. 8, which is a schematic diagram showing the semi-products of the heat sinks  4  in various shapes with radiation fins  41 . The heat transfer promoting material  2  will form the central part  421  of the top surface  42  of the semi-product of the heat sink  4 , and the main material  1  will form the surrounding part  422  of the top surface  42  of the semi-product of the heat sink  4 .  
         [0031]    Please refer to FIG. 9, which is a schematic diagram showing the final-products of the heat sinks  5  in various shapes with radiation fins  51 . These final-products of the heat sink  5  are produced from the semi-products of the heat sink  4  by the following steps: 1. cutting the top surface  42  of the semi-product of heat sink  4  into a base plate  52  of the heat sink  5 ;  2 . grinding the base plate  52  of the heat sink  5 . The heat transfer promoting material will form the central part  521  of the top surface  52  of the semi-product of the heat sink  5 , and the main material will form the surrounding part  522  of the top surface  52  of the semi-product of the heat sink  5 .  
         [0032]    In conclusion, the present invention would effectively improve the drawbacks of the prior art regarding the environmental protection problems as well as saving the manufacturing costs and improving the quality of the heat sinks without plating and brazing processes. Thus, the present invention has its value in the industry, and the purpose of developing the present invention is achieved.  
         [0033]    While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures. Therefore, the above description and illustration should not be taken as limiting the scope of the present invention which is defined by the appended claims.