JPH0966343A - Precise casting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a precise casting method for easily removing a coating layer by reducing the number of coating layers of hole parts or recessed parts so far as a necessary strength can be obtained. SOLUTION: Formed waxes 21 having the same shaped hole part 21a and recessed part 21b as a product, are formed. The formed waxes 21 are integrally assembled into tree-shape, and the assembly is coated with smaller numbers of layers of molding material 25 than the regular member of layers to manufacture the mold 26. Combustible materials 32, 31 are inserted respectively into the hole parts 21a and the recessed parts 21b of the formed wax 21 covered with the molding material 25, and again, the molding material 30 is applied for the normal number of layers. The formed wax 21 is melted and removed from the coating layer, and at the time of burning process, the combustible materials 32, 31 are burnt. Molten metal is poured into a space formed by removing the formed wax and solidified, and the coating layers 25, 30 are removed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a precision casting method (lost wax casting method) used for precision casting,
In particular, the present invention relates to a precision casting method suitable for producing a precision cast product having holes and recesses.

[0002]

2. Description of the Related Art In general, in a precision casting method (lost wax casting method), first, a plurality of wax molded products having the same shape as the product are molded by injection molding, and then these wax molded products are collectively put into a tree. After assembling into a shape,
By spraying the refractory particles with the ceramic slurry applied around this assembly and repeating these several times. A number of coating layers are formed around the assembly, each wax molded product is melted and removed from the coating layer, molten metal is injected into the open spaces to solidify, and the coating layer is removed to take out each product. ing.

Here, a conventional precision casting method will be described by taking precision casting of a golf club head as an example. As shown in FIG. 7, a plurality of wax molded products 1, 2, 3, 4 having a pore 1a and a recess 1b and having the same shape as the product are molded. Here, the wax molded products 1, 2, 3, 4 are
The fine hole portion 1a and the concave portion 1b are the same shape as the golf club head, which is a shaft hole for inserting and mounting the shaft of the golf club and a hollow portion (cavity portion) of the golf club head. These wax molded products 1, 2, 3 and 4 are put together in a main runway K and assembled in a tree shape.

As shown in FIG. 8, a plurality of molds 6, 7, 8 and 9 are produced by coating a mold material around this assembly by a regular number of layers. Here, reference numeral 5 indicates a coating layer, and the regular number of layers means the molds 6, 7, 8,
The number of coating layers for ensuring the required strength of 9 is generally about 10. As shown in FIG. 9, each of the molds 6, 7, 8 and 9 is heated to melt each wax molded product (not shown) and removed from the coating layer 5. At this time, the melted wax is discharged from the main runner K as indicated by arrow A. After this, a firing process is performed. As shown in FIG. 10, the molds 6, 7, 8 and 9 are heated, and the wax moldings in the molds 6, 7, 8 and 9 are removed to form the respective spaces formed therein. , Through the main runway K (see arrow B) Molten metal 1
0, 11, 12, and 13 are injected to solidify.
As shown in FIG. 11, each mold 6 (7, 8, 9) is unmolded from the main runway K (see FIG. 10), the coating layer 5 is removed, and the product 10 is taken out. Finally, the auxiliary runner portion 14 of the product 10 is cut, and other parts are finished as necessary.

[0005]

However, in the above-mentioned conventional technique, as shown in FIG.
Since the concave portion 1b is also coated with the regular number of layers (see reference numerals 5a and 5b), the pore material 1a is clogged with the mold material, and it is difficult for the mold material to be cracked when the mold is released. In order to remove these coating layers 5a and 5b, it takes time and productivity becomes low, and when the pores 1a are opened by prying or opening by excessive shot blasting, the edges are rounded. It will get loose and scratched. Further, the coating layer 5b on the inner peripheral surface of the recess 1b is unlikely to break, and it takes a long time to remove it, resulting in low productivity.

The inventors of the present invention did not coat the mold material with a regular number of layers around the entire wax molded product,
Form a regular number of coating layers on the part of the shape of the wax molded product to secure the required strength of the mold, and do not require so much strength on the inner peripheral surface of the pores or recesses, and make that shape. It has been found that a sufficient number of coating layers, which is smaller than the regular number, may be formed.
Then, the present invention has been made in view of the problems of the above-described prior art, and the number of coating layers of the holes or recesses is reduced under the condition that required strength is obtained, and the coating layers are removed. It is an object of the present invention to provide a precision casting method that facilitates the production of the product without causing scratches or rounded edges and improves productivity.

[0007]

The precision casting method of the present invention for achieving the above object is to provide a casting material around a wax molded product having the same shape as the product and having holes or recesses with a regular number of layers. A small number of layers, a flammable material is inserted into the hole or recess of the wax molded article covered with the mold material, and the mold material is again surrounded by the less layer. A mold is made by coating the number of layers such that the sum of the number and the number of layers becomes a regular number, and the wax molded product is melted by heating the mold and removed from the coating layer. Characterized in that the material is burned out, molten metal is injected into the space of the mold formed by removing the wax molded product to solidify, and each coating layer of the mold is removed to take out the product. It is intended to.

According to another aspect of the invention, a plurality of wax molded products having the same shape as the product and having holes or recesses are assembled together in a tree shape, and the number of mold materials is less than the regular number of layers around this assembly. A combustible material is inserted into each of the holes or recesses of each wax molded product coated by the number of layers and covered with the mold material, and again, around the assembly covered with the mold material, and further with the mold material. , To prepare a mold by coating the number of layers such that the sum of the small number of layers is a regular number of layers, heating each mold to melt each wax molded product and remove from the coating layer, Further, the combustibles are burned to burn off, and molten metal is injected into each space of the molds formed by removing the wax moldings to solidify the melted metal. Is characterized in that the taking out the product, respectively, removing the coating layer.

Further, before or after the flammable material is inserted, a rod member made of a material which is melted by heating during dewaxing is inserted into the flammable material, and after the coating of the regular number of layers, the rod is inserted. Fold the parts. In the wax molded product, the hole or the recess is a shaft hole for inserting and mounting the shaft of the golf club or a hollow part of the golf club head.

The operation of the present invention will be described below. In the invention according to claim 1, first, the wax molding is coated with the casting material in the required number of layers for the holes or the recesses, and then the holes or the recesses of the wax molding covered with the coating layer are coated. , Insert a combustible material (also called a filler) that fits the shape. Where again
A mold material is coated around the wax molded product with a mold material until the regular number of layers is obtained to prepare a mold. At this time, the inner peripheral surface of the hole or the recess is covered with a combustible material, and thus is not coated. After that, the mold is heated to melt the wax-molded product and remove it from the mold, and a firing step is performed. During this firing step, the combustibles are burnt and burned out. Then, the mold is heated and, at the same time, the molten metal is injected into the space formed by removing the wax molded product and solidified. Finally,
Remove the product by breaking and removing the coating layer of the mold. Here, since the coating layer of the hole or the recess is thin, it can be easily broken.

According to the second aspect of the present invention, first, a plurality of wax molded products are assembled into a tree-like structure,
The mold material is coated by the required number of layers for the holes or recesses, and then a combustible material matching the shape is inserted into the holes or recesses of each wax molded product covered with the coating layer. Here, again, a plurality of molds are produced by coating the mold material around the assembly to a regular number of layers. At this time, the inner peripheral surface of the hole or the recess is covered with a combustible material, and thus is not coated. After that, each mold is heated to melt each wax molded product, removed from each mold, and a firing step is performed. At this time, the combustibles are burnt and burned out. After that, each of the molds is heated, and molten metal is injected into each of the spaces formed by removing the wax molded products and solidified. Finally, the coating layer of each mold is broken and removed to remove the product. Here, since the coating layer of the hole or the recess is thin, it can be easily broken.

According to the third aspect of the present invention, before the dewaxing step, the rod member is previously inserted into a combustible material and the rod member is folded together with the coating layer coated thereon,
The rod member remaining in the combustible material melts during the dewaxing process,
Gas vent holes are formed in the coating layer. Then, carbon dioxide generated by burning the combustible material is guided to the outside air through the gas vent hole to promote combustion and burning of the combustible material. The invention according to claim 4 is useful by applying the present invention to a golf club head that does not like variations in shape such as scratches and rounded edges.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. In the following, the present invention will be described with reference to a precision casting method in which a plurality of golf club heads as molded products are taken at once.

As shown in FIG. 1, a wax molded product 21 having the same shape as the product and having pores 21a and recesses 21b,
A plurality of 22, 23 and 24 are molded (injection molding process). Here, in each of the wax molded products 21, 22, 23, and 24, the pores 21a (hosel holes) and the recesses 21b of the wax molded products are shaft holes into which the shaft of the golf club is inserted and attached, or hollow parts of the golf club head. It has the same shape as the golf club head, which is the (cavity portion). These wax moldings 21, 22, 23,
24 are assembled together into a tree on the main runway K (assembly process). The symbol R indicates the runner mouth of the main runway K.

Around the assembly, a mold material 25 is coated by a smaller number of layers than the regular number of layers to form a mold 26,
27, 28 and 30 are produced. Here, the number of coating layers 25 is, for example, three, and the thickness is about 2 to 3 mm. The regular number of layers means the molds 26, 27, 2
It is the number of coating layers for ensuring the required strength of 8 and 29, and is generally about 10 layers.

As shown in FIG. 2A, the mold material 25 is used.
21 a of the wax molded product 21 covered with
And the recessed portion 21b, the flammable material 32,3 matching the shape
1 (also called a filler) is inserted. Although the flammable materials 31 and 32 are inserted into both the hollow portion 21b, which is the hollow portion of the golf club head, and the pore portion 21a for inserting and mounting the shaft, they may be inserted into either one. Here, the combustible material 3 with the larger volume
Before or after inserting 1, the rod member P is inserted into the combustible material 31. The rod member P is made of a material that is melted by heating during dewaxing, which will be described later, and is made of the same material as the wax molded product in this embodiment. Although not shown, combustible materials are inserted into the other wax molded products 22, 23, and 24, similarly to the wax molded product 21, respectively.

Again, about 7 layers of the mold material 30 are coated around the assembly until the regular number of layers (generally about 10 layers) is reached (coating step). At this time, since the pores 21a and the recesses 21b are covered with the combustibles 32 and 31, respectively, they are not coated. In this embodiment, the coating layer 25 formed by the previous coating
And the thickness of the coating layer 30 formed by the subsequent coating is about 8 to 10 mm. After this,
As shown in FIG. 2B, the rod member P is folded together with the coating layer 30 coated on it. In FIG. 2, the coating layer 30 is shown only for one wax molding 21, but it is actually coated on the entire assembly. Also, in the subsequent steps, the molds 27, 28 and 29 go through the same steps as the mold 26, and therefore their changing modes are not shown.

The combustibles 31 and 32 include wood chips, urethane foam, sponge, absorbent cotton, etc., and those which are difficult to absorb the mold material (coating material) are preferable. Further, the combustible material preferably has elasticity so as to match the shape of any pores and recesses, but when it is particularly rigid, it may be easily inserted into the pores or recesses in advance. It is preferable to have a shape that matches the shape of the pores and recesses. In this embodiment, urethane foam and wooden pins are used as the combustibles 31 and 32, respectively.

As shown in FIG. 3, the assembly is, for example,
The wax molded product 21 is heated to about 130 to 200 ° C,
22, 23, 24 are melted and removed from within the coating layer. At this time, the melted wax is discharged from the runner port R of the main runway K as indicated by arrow A. At this time, the rod member P (see FIG. 2B) remaining on the combustible material 31 is melted during the dewaxing process, and the gas vent hole C is formed in the coating layer 30. Further, the molds 26, 27, 2
8 and 29 are heated to, for example, about 1200 to 1300 ° C. and baked (dewaxing / baking step). At this time, when the mold is burned, the combustibles 31 and 32 (see FIG. 2) burn and burn out. The combustible material 31 with the larger volume (see FIG. 2)
The carbon dioxide generated when the fuel burns can be guided to the outside air through the gas vent hole C, and the combustion of the combustible material 31 can be promoted.

As shown in FIG. 4, each mold 26, 27, 2
8 and 29 are respectively heated, and molten metal 33 is introduced into the spaces formed by removing the wax molded products 21, 22, 23 and 24, respectively, via the main runner K (see arrow B). Each is poured and solidified (casting process).

As shown in FIG. 5, each mold 26 (27, 2)
(8, 29) is unmolded from the main runner K, the coating layers 25, 30 are removed, and the product is taken out (unmolding step). Here, since the coating layers 25a and 25b of the pores 21a and the recesses 21b are thin, they can be easily broken. That is, the disintegration property of the mold 26 is improved. Finally, the auxiliary runner 34 of the product 33 is cut, and other parts are finished as necessary (cutting / finishing step).

As shown in FIG. 6, the bottom portion 35 of the separately molded golf club is attached to the molded product 33 molded as described above by, for example, welding, and the shaft 37 of the golf club is attached to the neck. Shaft insertion hole 21 of portion 38
Insert into a and attach to obtain a golf club. Reference numeral 36 indicates a face surface, and reference numeral 39 in FIG. 5 indicates an abutting portion (flange portion) with which the end surface of the shaft 37 abuts.

The present invention has been described above with respect to a precision casting method in which four golf club heads as molded products are taken at a time, but of course the invention is not limited to this, and automobiles having recesses or holes as molded products are described. The present invention can also be applied to the case where there are parts and the like, and as in the invention described in claim 1, the product is precision-cast one by one (one by one).

Furthermore, when a combustible material is inserted into either the pores or the recesses for molding, the strength of the recesses is lower than the strength of the pores. It is preferable to increase the number in the case of the concave portion than in the case of the fine portion.

Further, in the above embodiment, the step of inserting the rod member made of wax into the combustible material and further folding the rod member in order to form the gas vent hole was carried out. However, the present invention is not limited to this. A metal pipe member may be inserted into the combustible material so that the opening end of the pipe member is not blocked by the coating layer during the subsequent coating.

[0026]

Since the present invention is configured as described above, it has the following effects. In the invention according to claim 1, first, a wax molded product is coated with a required number of layers for the holes or recesses, and then the shape of the hole or recess of the wax molded product covered with the coating layer is formed. Insert a combustible material suitable for. Here, again, a mold material is coated around the wax molded product until the regular number of layers is achieved. At this time, since the hole or recess is covered with combustible material,
Not coated. After that, the wax molded product is melted and removed from the coating layer, and a firing process is performed. At this time, the combustibles burn and burn out. Molten metal is poured into the space formed by removing the wax molded product and solidified. Finally, the coating layer is removed and the product is removed. Here, since the coating layer of the hole or the recess is thin, it can be easily broken. As a result, you can pry open the hole,
It is possible to provide a precision casting method in which the product is not scratched or the edge is not rounded without performing excessive shot blasting and the productivity is improved. In the invention described in claim 2, a plurality of products can be obtained at a time, the above effects can be achieved for each product, and the above effects are added for the number of products. It will be even more useful. The invention according to claim 3 guides carbon dioxide generated when a combustible substance burns to the outside air through a gas vent hole to promote combustion of the combustible substance,
The productivity can be further improved. The invention according to claim 4 becomes useful by applying the present invention to a golf club head that does not like uneven shapes such as scratches and rounded edges.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a wax molded product assembly according to a precision casting method of the present invention after a first-stage coating is performed.

FIG. 2 is a cross-sectional view related to the precision casting method of the present invention after a flammable material is inserted and subsequent coating is sequentially performed.

FIG. 3 is a dewaxing process according to the precision casting method of the present invention.
It is sectional drawing after a baking process.

FIG. 4 is a cross-sectional view after a casting process according to the precision casting method of the present invention.

FIG. 5 is a cross-sectional view of the mold after the mold release according to the precision casting method of the present invention.

FIG. 6 is a perspective view of an essential part of a golf club provided with the golf club head obtained according to the present invention.

FIG. 7 is a cross-sectional view of a wax molded product assembly according to a conventional precision casting method.

FIG. 8 is a cross-sectional view after coating the assembly shown in FIG.

FIG. 9 is a cross-sectional view after a dewaxing / firing process according to a conventional precision casting method.

FIG. 10 is a cross-sectional view after a casting step according to a conventional precision casting method.

FIG. 11 is a cross-sectional view of a mold after unmolding according to a conventional precision casting method.

[Explanation of symbols]

C Gas vent hole K Main runway P Bar member R Runner port 21,22,23,24 Wax molded product 21a Pore part (shaft insertion hole) 21b Recessed part (hollow part) 25 Coating layer by the previous coating process 25a Pore Coating layer applied to the parts 25b Coating layer applied to the recesses 26, 27, 28, 29 Mold 30 Coating layer in the previous coating process 31, 32 Combustibles (urethane foam, wooden pins) 33 Molten metal (molded product) 34 Auxiliary Runner part 35 Bottom part 36 Face surface 37 Shaft 38 Neck part

Claims (4)

[Claims] 1. A wax molded product having the same shape as a product and having a hole or a concave portion coated with a mold material in a smaller number of layers than the regular number, and covered with the mold material. Insert a flammable material into the hole or the recess of, and coat the mold material again around the mold material by the number of layers such that the sum of the small number of layers is the regular number of layers. Formed by removing the wax molded product of the mold by producing a mold, melting the wax molded product by heating the mold to remove it from the coating layer, and further firing to burn off the combustible material. A precision casting method, characterized in that molten metal is injected into the formed space to solidify, and each coating layer of the mold is removed to take out the product. 2. A plurality of wax molded products having the same shape as the product and having holes or recesses are assembled together in a tree shape, and a mold material is coated around the assembly in a number smaller than the regular number of layers. Inserting a combustible material into the hole or recess of each wax molded article covered with the mold material, and again, around the assembly covered with the mold material, further adding the mold material to the less layer. A mold is prepared by coating the number of layers such that the sum of the numbers becomes a regular number, and each wax molded product is melted by melting each wax molded product and removed from the coating layer, and further baked. The flammable material is burned off, and the molten metal is injected into the spaces formed by the removal of the wax moldings of the respective molds to solidify them, and the respective coatings are applied from the respective molds. A precision casting method, characterized in that the layers are removed and the products are respectively taken out. 3. A rod member made of a material that is melted by heating during dewaxing is inserted into the flammable material before or after the flammable material is inserted, and after the coating of the regular number of layers, the rod is inserted. The precision casting method according to claim 1, wherein the member is broken. 4. The wax molded product according to claim 1, wherein a hole or a recess thereof is a shaft hole for inserting and mounting a shaft of a golf club or a hollow part of a golf club head. The precision casting method according to item 1.