Patent Grant
9545661
1. Field of the Invention
The present invention generally relates to a casting method for manufacturing a golf club head and, more particularly, to a casting method for manufacturing a golf club head having an embedded heterogeneous material different from the cast material.
2. Description of the Related Art
In order to meet the needs of a low and deep gravity center, vibration resistance and a comfortable hitting feeling, heterogeneous material different from cast material is currently used in several kinds of golf club heads. By embedding the heterogeneous material into the golf club head, the gravity center of the golf club head and the feeling of the user hitting a golf ball can be adjusted. The heterogeneous material is usually used in the toe, the sole, the heel, the back, the hosel or the striking face of the body of the golf club heads.
Current golf club heads are manufactured by using a high frequency induction furnace to rapidly melt the cast materials in the atmosphere, followed by removing slag and gases in the molten metal by slagging and refinery, Static gravity pouring is then carried out. For maintaining the flowability of the molten metal, the shell mold should be preheated at a high temperature before the pouring process. However, when manufacturing the golf club head with the heterogeneous material, the heterogeneous material in the shell mold is apt to react with oxygen in the air, forming an oxide layer on the surface of the heterogeneous material. Therefore, the coupling strength between the cast material and the heterogeneous material is decreased. Moreover, the heterogeneous material has a thermal expansion coefficient different from the cast material, such that the high temperature used to heat the shell mold during the gravity pouring process often easily causes loosening between the cast material and the heterogeneous material after cooling.
In addition, the static gravity pouring requires additional cast material to maintain the pressing effect of the molten metal and to improve the yield rate of the golf club heads. However, the use of additional cast material and energy for melting the additional cast material results in a higher cost.
Furthermore, if the cast material contains active metals, rigorous oxidation of the active metals may easily occur during the smelting process of the cast material. This not only increases the difficulty in melting but also easily causes oxidative fire cracks due to the reaction with air during the pouring process. As a result, appearance defects, such as sesame dot defects and black bean defects, are apt to be formed on the cast products of the golf club heads. In the worse situations, the reactive gas forms a large number of slag holes or blowholes in the cast products of the golf club heads and, thus, adversely affects the tensile strength of the golf club heads. Moreover, rigorous oxidation also reduces the flowability of the molten metal in the shell mold, leading to a reduced yield rate of the cast products of the golf club heads due to insufficient pouring or resulting in gaps in the cast products of the golf club heads due to cold shut. The tensile strength of the cast products of the golf club heads is also adversely affected. As a result, the yield rate of the cast products of the golf club heads with active metals manufactured by static gravity pouring in the atmosphere is severely decreased.
In light of this, it is necessary to improve the conventional method for manufacturing a golf club head.
It is therefore the objective of an embodiment of the present invention to provide a casting method for manufacturing a golf club head with a heterogeneous material to reduce the chemical reaction of the heterogeneous material with air during the smelting process, increasing the coupling strength between the cast material and the heterogeneous material (whether with or without active metals) and improving the yield rate and quality of the cast products.
It is another objective of an embodiment of the invention to provide a casting method for manufacturing a golf club head with a heterogeneous material for increasing the flowability of the molten metal in a shell mold. Thus, the shell mold can be preheated at a lower temperature, reducing the thermal expansion of the heterogeneous material and maintaining the tight coupling between the cast material and the heterogeneous material.
It is also another objective of an embodiment of the invention to provide a casting method for manufacturing a golf club head with a heterogeneous material to reduce the manufacturing cost without using additional cast material to maintain the pressing effect of the molten metal.
It is yet another objective of an embodiment of the invention to provide a shell mold with an enhanced coupling strength between the cast material and the heterogeneous material.
The present invention fulfills the above objectives by providing a casting method for manufacturing a golf club head with an embedded heterogeneous material, which comprises the following steps. A shell mold including a crucible portion, a casting portion with a cavity, and a coupling portion in intercommunication between the crucible portion and the casting portion is placed a shell mold on a rotary table. A heterogeneous material including an embedded portion embedded in the casting portion and a non-embedded portion remaining in the cavity of the casting portion is partially embedded in the casting portion of the shell mold. A metal ingot is placed in the crucible portion of the shell mold. The metal ingot is melted into molten metal in a vacuum environment. The rotating shaft is driven to rotate the rotary table, causing the molten metal to flow into the cavity of the casting portion under a centrifugal force generated by the rotation. The non-embedded portion of the heterogeneous material is enclosed with the molten metal. After the molten metal cools and solidifies, the rotating shaft is gradually slowed down until the rotating shaft stops. After the molten metal completely solidifies, the shell mold is destroyed to obtain a casting comprising a cast product portion. The cast product portion is separated from the casting to obtain a cast product of a golf club head, with the embedded portion protruding from an outer periphery of the cast product of the golf club head. The outer periphery of the cast product of the golf club head is milled to remove the embedded portion that protrudes from the outer periphery of the cast product of the golf club head.
In a preferred form shown, formation of the shell mold further includes the following substeps. A wax blank including a crucible blank, a casting blank, a coupling blank and the heterogeneous material is prepared, with the coupling blank having an end connected with an outer periphery of the crucible blank and another end connected with the casting blank, and with the non-embedded portion of the heterogeneous material remaining in the casting blank and the embedded portion of the heterogeneous material protruding from the outer periphery of the casting blank. An enveloping layer is formed on an outer surface of the wax blank. The wax blank and the enveloping layer are heated to melt the wax. The dewaxed enveloping layer is sintered at a high temperature to form the shell mold. The crucible portion, the coupling portion and the casting portion of the shell mold are integrally formed together.
In a preferred form shown, the method further includes the following step. The heterogeneous material is partially embedded in a molten wax in an injection molding manner, to form the casting blank after the molten wax cools and solidifies.
In a preferred form shown, the method further includes the following step. The rotary table is rotated at a speed of 200-700 rpm, to allow the molten metal to flow into the cavity of the casting portion, to fill the cavity of the casting portion with the molten metal.
In a preferred form shown, the method further includes the following steps. The rotating speed of the rotary table is maintained at 200-700 rpm for 10-30 seconds. After the molten metal completely cools and solidifies, the rotary table is gradually slowed down until the rotary table stops.
In a preferred form shown, the method further includes the following steps. After the rotating shaft is completely stopped, the shell mold is removed from the rotary table. The shell mold is restricted from movement for a period of time. The shell mold is destroyed after the molten metal completely solidifies. Alternatively, after the rotary table stops rotating, the shell mold is constantly cooled on the rotary table. After the molten metal in the shell mold completely solidifies, the shell mold is removed from the rotary table and destroyed.
In a preferred form shown, the method further includes the following steps. The metal ingot in the crucible portion of the shell mold is melted into molten metal in the vacuum environment with an activated heater. The activated heater surrounds the crucible portion of the shell mold and heats the crucible portion. Moreover, the method further includes the following step. After the metal ingot is melted into molten metal, the activated heater is moved upward to a preset location surrounding the crucible portion by a lift controller and moved downward to a position not surrounding the crucible portion by the lift controller.
The present invention also fulfills the above objectives by providing a shell mold including a crucible portion, a casting portion, a coupling portion and a heterogeneous material. The coupling portion intercommunicates between the crucible portion and the casting portion. The casting portion includes a cavity. The heterogeneous material includes an embedded portion and a non-embedded portion coupling to the embedded portion, with the embedded portion inlaying in the casting portion of the shell mold and the non-embedded portion locating in the cavity of the casting portion.
In a preferred form shown, the embedded portion includes a first hook portion with a maximum sectional width larger than a sectional width of a part of the embedded portion that is connected to the non-embedded portion. Similarly, the non-embedded portion includes a second hook portion with a maximum sectional width larger than a sectional width of a part of the non-embedded portion that is connected to the embedded portion.
In a preferred form shown, the non-embedded portion includes a taper with a sectional width reducing from the non-embedded portion to the embedded portion.
In a preferred form shown, the embedded portion of the heterogeneous material has an average cross sectional area smaller than an average cross section area of the non-embedded portion of the heterogeneous material.
In a preferred form shown, the non-embedded portion of the heterogeneous material includes a large sectional area region and a small sectional area region. The small sectional area intercommunicates with the embedded portion of the heterogeneous material and the large sectional area region. The small sectional area has a maximum sectional area smaller than ⅔ and larger than 1/10 of the minimum sectional area of the large sectional area, forming a distance between the large sectional area of the casting cover portion and an inner periphery of the cavity.
In a preferred form shown, formation of the shell mold further includes the following substeps. A wax blank including a crucible blank, a casting blank, a coupling blank and the heterogeneous material is prepared, with the coupling blank having an end connected with an outer periphery of the crucible blank and another end connected with the casting blank, and with the non-embedded portion of the heterogeneous material remaining in the casting blank and the embedded portion of the heterogeneous material protruding from the outer periphery of the casting blank. An enveloping layer is formed on an outer surface of the wax blank. The wax blank and the enveloping layer are heated to melt the wax. The dewaxed enveloping layer is sintered at a high temperature to form the shell mold. The crucible portion, the coupling portion and the casting portion of the shell mold are integrally formed together.
In a preferred form shown, the casting blank of the wax blank has a filling portion on the surface of the heterogeneous material. The filling portion is adjacent to the heterogeneous material and is in a form of a protruded edge or a plurality of protruded spots.
The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:
In the various figures of the drawings, the same numerals designate the same or similar parts. Furthermore, when the term “first”, “second”, “third”, “fourth”, “inner”, “outer”, “top”, “bottom” and similar terms are used hereinafter, it should be understood that these terms refer only to the structure shown in the drawings as it would appear to a person viewing the drawings, and are utilized only to facilitate describing the invention.
Specifically, the vacuum furnace 1 includes a chamber 11. A gas-guiding tube 12 can be mounted to the vacuum furnace 1 and intercommunicates with the chamber 11. A vacuum controller (not shown) can be operated to control the vacuum level in the chamber 11 by drawing gas out of the chamber 11 via the gas-guiding tube 12 according to the preset values. Furthermore, the vacuum furnace 1 can include an opening 13, permitting a user to place an object into the chamber 11 or retrieve the object out of the chamber 11, and a cover 14 can be provided to open or close the opening 13.
With reference to
Furthermore, a portion of the rotating shaft 2 in the chamber 11 can include a body 21 and a stop portion 22. Cross sections of the body 21 perpendicular to the rotating axis are different from cross sections of the stop portion 22 perpendicular to the rotating axis, forming an abutment portion 23 at an intersection between the body 21 and the stop portion 22. The rotary table 3 is coupled to the stop portion 22 and abuts the abutment portion 23 such that the rotary table 3 synchronously rotates with the rotating shaft 2. In this embodiment, the cross sections of the body 21 perpendicular to the rotating axis are circular. The stop portion 22 is located on an end of the rotating shaft 2, and the cross sections of the stop portion 22 perpendicular to the rotating axis are non-circular, allowing the rotary table 3 to couple with the stop portion 22 and to abut the abutment portion 23.
With reference to
Referring to
The crucible portion 41 and the casting portion 42 of the shell mold 4 can be positioned in the crucible-positioning portion 32a and the cavity-positioning portion 32b of the rotary table 3, respectively. Therefor, the crucible portion 41 is closer to the shaft-coupling portion 31 of the rotary table 3 than the casting portion 42 is to the shaft-coupling portion 31 of the rotary table 3. Thus, as the rotary table 3 is driven to rotate, cast materials received in the receiving space 411 of the crucible portion 41 can flow into the cavity 421 of the casting portion 42 under centrifugal force.
It's worth to mention that, for adjusting the gravity center of the golf club head or the feeling of the user hitting a golf ball, the cavity 421 of the casting portion 42 includes at least one heterogeneous material 6 embedded in the body of the golf club head. A part of the heterogeneous material 6 is embedded in the cavity 421, and another part of the heterogeneous material 6 is embedded in the casting portion 42. As such, the heterogeneous material 6 can remain in the preset location of the cavity 421, such that the heterogeneous material 6 can be enclosed by the cast material flowing into the cavity 421. The cast material flowing into the cavity 421 under a centrifugal force is a high-temperature molten metal used for forming the body of the golf club head. Therefore, the melting point of the heterogeneous material 6 should be higher than the melting point of the cast material to prevent melting of the heterogeneous material 6. The density of the heterogeneous material 6 can be adjusted according to the needs of the manufacturing process. That is, the heterogeneous material 6 having a density lower than the cast material can be used for reducing the local weight of the golf club head. Alternatively, the heterogeneous material 6 having a density higher than the cast material can be used for increasing the local weight of the golf club head.
Referring to
Moreover, because the embedded portion 61 of the heterogeneous material 6 should be milled after the cast product is formed, the embedded portion 61 of the heterogeneous material 6 preferably has a smaller volume. For example, the average cross sectional area of the embedded portion 61 of the heterogeneous material 6 is smaller than the average cross sectional area of the non-embedded portion 62 of the heterogeneous material 6. However, the relationship must be based on the fact that the embedded portion 61 can sufficiently support the non-embedded portion 62, as it can be easily appreciated by a person having ordinary skill in the art.
Furthermore, the outer periphery of the produced cast product will probably have to be milled in order to expose a portion of the non-embedded portion 62 out of the cast product (said portion is the part of the non-embedded portion 62 adjacent to the embedded portion 61). However, the milling process of the heterogeneous material 6 is usually more difficult than the milling process of the cast material. Therefore, the portion of the heterogeneous material 6 exposed outside of the cast product preferably has a cross section as small as possible. In this embodiment, the non-embedded portion 62 of the heterogeneous material 6 can have a small sectional area region 62a and a large sectional area region 62b, with the small sectional area region 62a being interconnected with the embedded portion 61 of the heterogeneous material 6 and the large sectional area region 62b. The small sectional area region 62a has a maximum sectional area smaller than about ⅔ and larger than 1/10 of the minimum sectional area of the large sectional area region 62b, forming a distance between the large sectional area region 62b of the non-embedded portion 62 and an inner periphery of the cavity 421. With such performance, the produced cast product can be in a form that can be easily milled. Therefore, the efficiency of milling the cast product is improved, and the wearing of the milling tool is reduced.
With reference to
It's worth to mention that any portion of the casting blank 72 can be connected to the coupling blank 73. That is to say, any portion of the casting blank 72 can be used as a pouring opening. Moreover, any portion of the casting blank 72 connecting with the coupling blank 73 can include a plurality of portions according to the arrangement of the passage for improving the yield rate of the cast products, which is understood by a person having ordinary skill in the art.
Next, an enveloping layer 8 is formed on an outer surface of the wax blank 7 by dipping, coating or clogging. Then, the wax blank 7 and the enveloping layer 8 are heated to melt the wax. As an example, the wax blank 7 and the enveloping layer. 8 can be heated in a steam autoclave to melt the wax blank 7, and the molten wax flows out of the enveloping layer 8. The dewaxed enveloping layer 8 is sintered at a high temperature to form the integrally formed shell mold 4 including the crucible portion 41, the coupling portion 43 and the casting portion 42, with the embedded portion 61 of the heterogeneous material 6 embedded in the casting portion 42 of the shell mold 4. A fire-resistant material, such as zirconium silicate, yttrium oxide, stabilized zirconium oxide or aluminum oxide, can be used as the material for a surface layer of the shell mold 4. A mullite (3Al2O3-2SiO2) compound or silicon oxide can be used as a fire-resistant material for a back layer of the shell mold 4. In a case that the back layer uses a mullite compound, the mullite compound preferably contains 45-60 wt % of aluminum oxide and 55-40 wt % of silicon oxide. In another case that the back layer uses a silicon oxide compound, the silicon oxide compound preferably contains more than 95% of silicon oxide.
With reference to
The method for manufacturing a golf club head having an embedded heterogeneous material according to the present invention can be implemented and includes the following steps.
With reference to
At least one metal ingot “P” is placed into the receiving space 411 of the crucible portion 41. In a case that the at least one metal ingot includes only one metal ingot “P”, the metal ingot “P” has a composition identical to a composition of a golf club head to be produced. In another case that the at least one metal ingot includes a plurality of metal ingots “P”, a composition of the molten metal of the metal ingots “P” is identical to a composition of a golf club head to be produced. As an example, nine examples of the alloy used as the metal ingot “P” are shown in, but not limited to, TABLE 1.
11-12.5
11-12.5
Referring to TABLE 1, the alloy shown as Examples 1 and 2 is an iron-based material containing aluminium (Al), silicon (Si), and manganese (Mn). The iron-based material has an iron content of above 50%, a density of 6.8 g/cm3, a tensile strength of 145-155 ksi, and is belonged belongs to a low-density steel material having a density of 6.5-7.8 g/cm3. Moreover, the alloy shown as Examples 3-6 is an iron-based material containing cobalt (Co), molybdenum (Mo) or titanium (Ti). The iron-based material in Examples 3-6 has an iron content of above 50%, a density of 7.8 g/cm3, a tensile strength of 250-350 ksi, and belongs to a high-strength steel material having a tensile strength of above 240 ksi. Furthermore, the alloy shown as Example 7 is an iron-based material with a chromium content of 15-30 wt %, a density of 7.5-8 g/cm3 and a tensile strength of 90-110 ksi. Finally, the alloy shown as Examples 8-9 is titanium alloy having a titanium content of 85-95 wt %, a density of 4.2-4.6 g/cm3 and a tensile strength of 100-150 ksi.
With reference to
With reference to
After the pouring process, the rotating shaft 2 is still driven to rotate the rotary table 3. For example, in this embodiment, the rotary table 3 can be driven to rotate about the rotating axis at a speed of about 200-700 rpm for 10-30 seconds until the molten metal “N” at the pouring opening (the interior space of the coupling portion 43 of the shell mold 4) cools and solidifies. Rotating of the rotary table 3 is then slowed and finally stopped. Therefore, during cooling and solidification of the molten metal “N” according to the present invention, the pressing effect of the molten metal “N” is evaluated by the centrifugal force due to the rotation, thereby improving the yield rate of the golf club heads.
With reference to
The casting includes a cast product portion. The cast product portion is separated from the casting (such as by cutting the cast product portion from the casting using a cutter or by breaking the cast product portion off the casting under vibration) to obtain at least one cast product of a golf club head “W.” The cast product of the golf club head “W” can tightly enclose the non-embedded portion 62 of the heterogeneous material 6 while the embedded portion 61 of the heterogeneous material 6 protrudes from the outer periphery of the cast product of the golf club head “W.” Then, a golf club head having an embedded heterogeneous material 6 can be obtained by milling the outer periphery of the cast product of the golf club head “W” by a miller (not shown), removing the portion of the heterogeneous material 6 protruding from the outer periphery of the cast product of the golf club head “W”, including the embedded portion 61 and a small portion of the non-embedded portion 62. As such, a finished product of the golf club head having an embedded heterogeneous material 6 can be obtained.
Thus, the casting method for manufacturing a golf club head according to the present invention can be produced in a nearly vacuum environment to reduce the formation of the oxide layer on the surface of the heterogeneous material 6 during the preheating step of the shell mold. Therefore, the coupling strength between the cast material and the heterogeneous material 6 can be improved after the pouring process. The casting method for manufacturing a golf club head according to the present invention can also reduce the chemical reaction of the cast material with air during the smelting process, such that both the cast material (whether with or without active metals) and the metal ingot “P” can easily and more evenly melt to avoid oxidative fire cracks resulting from the reaction with air while the molten metal “N” is flowing from the crucible portion 41 of the shell mold 4 into the casting portion 42. Thus, appearance defects, such as sesame dot defects and black bean defects, are less likely to be formed on the cast product of the golf club head “W.” Furthermore, casting defects of slag holes or blowholes formed by the reactive gas are less likely to be generated, increasing the tensile strength of the cast product of the golf club head “W.”
Furthermore, reducing the chemical reaction between the molten metal “N” and air also increases the flowability of the molten metal “N” in the shell mold 4. Furthermore, the molten metal “N” is reliably poured into the cavity 421 of the shell mold 4 under centrifugal force before the molten metal “N” re-solidifies, which not only avoids the waste of the cast material due to solidification of a portion of the molten metal “N” in the crucible portion 41 but assures that the casting portion 42 can be filled with the molten metal “N” and that the non-embedded portion 62 of the heterogeneous material 6 can be completely enclosed by the molten metal “N” after the molten metal “N” flows into the casting portion 42. The yield rate of the cast products of the golf club heads can be increased, and the possibility of formation of gaps in the cast products of the golf club heads due to cold shut is reduced. Thus, the tensile strength of the cast product of the golf club head is increased. In addition, the required temperature for preheating the shell mold 4 can be reduced by increasing the flowability of the molten metal “N” under the vacuum environment as well as by further increasing the flowability of the molten metal “N” under centrifugal force. Therefore, the thermal expansion of the heterogeneous material 6 is decreased while maintaining the coupling strength between the cast material and the heterogeneous material 6 after cooling with a plurality of portions for forming the cast product of the golf club head “W”
Moreover, referring to
With reference to
Therefore, when the shell mold 4 used in the casting method for manufacturing a golf club head having an embedded heterogeneous material according to the present invention is shaped, the non-embedded portion 62′ of the heterogeneous material 6′ has the second hook portion 621′ embedded in the casting blank 72 of the wax blank 7 and the embedded portion 61′ exposed out of the outer periphery of the casting blank 72. When an enveloping layer 8 is formed on the outer surface of the wax blank 7, the embedded portion 61′ of the heterogeneous material 6′ can intercommunicate with the enveloping layer 8 via the first hook portion 611′, followed by sintering the dewaxed enveloping layer 8 to form the integrally formed shell mold 4, allowing the first hook portion 611′ of the embedded portion 61′ to be stably embedded in the casting portion 42 of the shell mold 4.
With reference to
More importantly, when the casting method of the application is used to manufacture a golf club head having the heterogeneous material 6′ embedded at the hosel of the golf club head, the coupling strength between the heterogeneous material 6′ and the cast material is significantly increased by the casting process, effectively reducing loosening between the heterogeneous material 6′ and the cast material resulting from a different thermal expansion coefficient therebetween. Moreover, the heterogeneous material 6′ and the cast material can be coupled with each other during the formation of the golf club head without requiring a later welding work, greatly simplifying the manufacturing process of the golf club head and improving the efficiency in manufacturing the golf club head.
The heterogeneous materials 6, 6′ are used as counter weights to change the gravity center of the golf club head in the embodiments as mentioned above. The following embodiment is made to explain the use of the heterogeneous material 6″ for adjusting the feeling of the user hitting a golf ball using such a produced golf club head. Referring to
Similarly, when the casting method of the application is used to manufacture a golf club head having the heterogeneous material 6″ arranged on the striking face of the golf club head, the coupling strength between the heterogeneous material 6″ and the cast material is significantly increased by the casting process, effectively reducing loosening between the heterogeneous material 6″ and the cast material resulting from a different thermal expansion coefficient therebetween. Moreover, the heterogeneous material 6″ and the cast material can be coupled with each other during the formation of the golf club head without requiring a later welding work, greatly simplifying the manufacturing process of the golf club head and improving the efficiency in manufacturing the golf club head.
In view of the foregoing, the casting method for manufacturing a golf club head having an embedded heterogeneous material according to the present invention can reduce the chemical reaction of the cast material with air during the smelting process, which not only reduces the formation of the oxide layer on the surface of the heterogeneous material, but also improves the coupling strength between the heterogeneous material and the cast material whether the cast material includes active metals or not. Therefore, the casting method for manufacturing a golf club head having an embedded heterogeneous material according to the present invention can improve the yield rate and the quality of the cast product.
Furthermore, the casting method for manufacturing a golf club head having an embedded heterogeneous material according to the present invention can improve the flowability of the molten metal in the shell mold by the pouring process under a centrifugal force in the vacuum environment, reducing the required temperature used for preheating the shell mold. Therefore, the thermal expansion of the heterogeneous material can be reduced, and the enhanced coupling effect between the cast material and the heterogeneous material can be maintained.
Moreover, the casting method for manufacturing a golf club head having a heterogeneous material according to the present invention can provide the desired pressing effect of the molten metal under the centrifugal force during solidification of the molten metal “N” without using extra cast material and energy. Thus, the casting method for manufacturing a golf club head having a heterogeneous material according to the present invention is capable of reducing the manufacturing cost.
In addition, the shell mold according to the present invention can improve the coupling strength between the cast material and the heterogeneous material of the cast product of the golf club head.
Although the invention has been described in detail with reference to its presently preferable embodiments, it will be understood by one of ordinary skill in the art that various modifications can be made without departing from the spirit and the scope of the invention, as set forth in the appended claims.
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| 20150190686 A1 | Jul 2015 | US |
