Abstract:
A manufacturing method of a clubface of a golf club reduces the amount of the metallic material used and enhances production. The manufacturing method includes the following steps: a metal powder and a binder are mixed to form a mixture; the mixture is shaped by a clubface mold to form a primary clubface; the primary clubface is then heated to a sintering temperature of the metal powder to form a clubface, before the clubface is finally compacted to make it stronger and increase the clubface&#39;s density.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates in general to a clubface of a golf club and a method for fabricating the same, which is a clubface a golf club having an integral structure and using the technologies of powder metallurgy and injection molding.  
         [0003]     2. Description of the Prior Art  
         [0004]     Because the clubface of a golf club must withstand massive impact forces, it needs to be constructed of high intensity metallic materials. Another aspect of the prior art is that clubfaces of golf clubs usually have a curved surface rather than planar one. Therefore, the manufacturing processes are very complex. The higher intensity the metal has, the higher its melting point is. Therefore conventional casting methods cannot make clubfaces.  
         [0005]     Reference is made to  FIG. 1 , which is a side view of a clubface of a golf club according to prior art. A clubface  94  is fixed on a club head  92  of a golf club  9 . A conventional method uses a very hard tool that is assembled on a lathe or a milling machine to cut out the curved surface. However the conventional method wastes a processed portion  96  as shown in  FIG. 1 , which is an expensive metal. Moreover, the producing method cannot be speed up to reach the needs of mass production.  
       SUMMARY OF THE INVENTION  
       [0006]     An objective of the present invention is to provide a clubface of a golf club and a method for fabricating the same, which raises output to reach mass production scale, and also reduces waste.  
         [0007]     In order to achieve the above objectives, the present invention provides a manufacturing method for a clubface of a golf club, which comprises the following steps: a metal powder and a binder are mixed to form a mixture; the mixture is shaped by a clubface mold to form a primary clubface; the primary clubface is then heated to a sintering temperature of the metal powder to form a clubface, and compacting the clubface finally to make it stronger and increase the density of the clubface. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]     The invention will be better understood and objectives other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the attached drawings, wherein:  
         [0009]      FIG. 1  is a side view of a clubface a golf club according to prior art;  
         [0010]      FIG. 2  is a flowchart of a manufacturing method of a clubface of a golf club according to the present invention; and  
         [0011]      FIG. 3  is a side view of a clubface a golf club according to the present invention. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0012]     Reference is made to  FIG. 2 , which is a flowchart of a manufacturing method for a clubface of a golf club according to the present invention. The manufacturing method of a clubface chiefly uses powder metallurgy (P/M) technology, which includes at least four steps: a mixing step  10 , a shaping step  20 , a heating step  30  and a compacting step  40 .  
         [0013]     In the mixing step  10 , a metal powder and a binder are mixed to form a mixture. The metal powder preferably has the characteristics of high hardness and low specific weight. For example, Ti (titanium) or a titanium alloy that has the characteristic of high hardness so that it can withstand strong impacts. Titanium is a gray metal, of which the specific weight is 4.5 and the melting point is 1668 degrees centigrade. It is a very special metal, is very light and very firm and is able to endure erosion. Tungsten carbide alloy also has high hardness, but the specific weight is higher. It is better that the metal powder is smaller, which is usually under 80 μm. However this does not limit the diameter of the metal powder. The smaller the metal powder is the bigger the surface area is, and the space thereof is reduced. Thereby, the metal powder is stacked more closely, and is sintered together more easily to reduce the required time of the heating step  30 . The size of the metal powder affects not only the density of the sintered product, but also the performance thereof. The smaller the metal powder is the larger the specific surface area (area/weight) is. A large specific surface area is very important. The binder is used for combining the metal powder, and can be a macromolecule binder or an organic binder (such as thermoplastic resin or wax).  
         [0014]     In the mixing step  10 , which can further include a step of providing a stirring machine for mixing and compressing the mixture, the mixture is formed using the metal powder and the binder. The mixture is then used as a raw material for shaping.  
         [0015]     In the shaping step  20 , the present invention chiefly uses injection molding technology (metal injection molding (MIM)) to mold the mixture and form a primary clubface via a clubface mold. During the process of injection molding, an injection-molding machine is required. Firstly, injection molding machine needs a preheating step during the process of injection molding, which heats the mixture so that it takes on some of the characteristics of a fluid. Next, the fluid mixture is injected into the clubface mold. At this stage the mixture is still in a soft state as it is yet to go through the heating stage that properly forms, hardens and strengthens the clubface. Injection molding technology is a proven technology, which can increase production speed.  
         [0016]     The present invention is not limited by to injection molding technology, and also can use press-molding technology. Firstly, a controlled amount of the mixture powder is fed into a precise mold (die) and the mixture is compacted in the mold by an upper and lower compacting machine to gain a primary clubface. The primary clubface is a compacted component, which is usually said to be in a “green” or soft state.  
         [0017]     In the heating step  30 , the primary clubface is heated to a sintering temperature of the metal powder to form a clubface. After pressing, the primary clubface is sintered by heating, and the binder therein will become dehydrated. In the heating step  30 , the primary clubface is usually passed through an ore-sintering furnace in which both temperature and atmosphere are strictly controlled by computer. The primary clubface is heated, so that the metal powders (particles) are fused, or sintered, together into a solid mass (the clubface). During the sintering step, a protective air, such as an inert gas like nitrogen, is aerated into the ore-sintering furnace to avoid the metal powder becoming oxidized. The sintering temperature is just below the melting point of the principal material, and is usually two thirds of the melting point of the principal material (i.e. the metal powder), which will allow the sintering process to take place. Of course the sintering temperature can reach or exceed the melting point. For example, the melting point of titanium is 1668 degrees centigrade, and the sintering point is over 1125 degrees centigrade.  
         [0018]     The final step is enhancing structural intensity, which includes a compacting step of compacting the clubface. Therefore, the clubface will be more compact and solid than the sintered mass. The primary clubface usually is slightly bigger that the predetermined size of the clubface, so that it will reach the predetermined size after compacting.  
         [0019]     The above-mentioned steps complete a clubface of a golf club according to the present invention. The present invention chiefly applies the technolygies of powder metallurgy and metal injection molding (MIM). The shape of the clubface according to the method of the present invention can be changed easily. Reference is made to  FIG. 3 , which is a side view of a clubface of a golf club according to the present invention. The clubface  1  has a main portion  12  and a curved striking-surface  122  formed on a top surface of the main portion. The main portion  12  is made of a single metallic material with a sintered structure. Via the manufacturing method of the present invention, the striking-surface  122  can be easily made with various shapes to enhance the ball-controlling ability, such as that formed with a plurality of protrusions  124  to increase the ball-grasping ability, or with a plurality of grooves.  
         [0020]     A summary of the characteristics and advantages of the present invention are as follows:  
         [0021]     1. The clubface of a golf club according to the present invention can to be easily made with various shapes to enhance the ball-controlling ability.  
         [0022]     2. The manufacturing method of the clubface of a golf club according to the present invention can reach the scale of mass production.  
         [0023]     3. The clubface of a golf club according to the present invention does not waste material, and needs even fewer material than the prior art because of the sintered structure, so that can reduce the costs of the metallic material.  
         [0024]     Although the present invention has been described with reference to the preferred embodiments thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the invention as defined in the appended claims.