JP3013583B2 - Assembly for precision casting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention mainly relates to a lost wax casting process in which molded products having the same shape as a product are molded, assembled in a tree shape, coated, and then the molded product is treated with metal. The present invention relates to a precision casting assembly for casting a product by replacement.

[0002]

2. Description of the Related Art In general, in a lost wax casting method, first, a wax molded product having the same shape as a product is molded by injection molding, and then these wax molded products are assembled together in a tree shape. By spraying refractory particles with the ceramic slurry applied around the assembly and repeating this several times, a large number of coating layers are formed around the assembly, dried, and further molded into wax. Dissolve the (assembly), remove it from the coating layer, inject molten metal into the open space,
Finally, the product is removed by removing the coating layer.

As shown in FIG. 6, a plurality of molded article connecting portions 3 are arranged at equal intervals on a horizontal member 2 on which a gate section 1 is formed. Three sets of support portions 4 are protruded from the pair of molded product connecting portions 3 and the gate section 1, the horizontal member 2, and the molded product connecting portion 3 are provided.
And the support part 4 is integrally formed by wax,
It is known that a metal attachment 5 protrudes from an end of the gate section 1 and a metal round bar 6 is inserted into a tip end of each molded product connecting portion 3. Then, the wax gate section 1, the horizontal member 2, the molded article connecting section 3 and the support section 4, and the metal attachment 5, the round bar 6 are simultaneously molded as an integrated product by insert molding. It is supposed to be.

[0004]

By the way, when a product is cast into a mold formed by using the above-mentioned wax assembly by pouring a molten metal from a sprue portion thereof, each of the above-mentioned molded product connecting portions (runners) Part) 3, there is a problem that a defect is likely to occur in a product in a part near the gate of the molded article connecting part (runner part) 3 located on both sides. Then, as a result of the present inventors investigating the cause, when the molten metal is poured from the gate of the mold, each molded product connection portion and the product space connected to them are sequentially arranged from the bottom. It is necessary for the molten metal to be filled in order to obtain a high quality product, but before the flow of the molten metal to be filled from the bottom of the mold reaches the empty space for forming the product in the above site, , Because part of the molten metal injected from the gate enters directly through the inner wall of the runner,
It was found that the molten metal was not filled at a time, and a product of desired quality could not be obtained.

The present invention has been made on the basis of the above-mentioned findings, and it is an object of the present invention to fill molten metal into each product space in order and all at once. It is an object of the present invention to provide a precision casting assembly which can prevent a defect from occurring in a product in a part close to the above and can stably obtain a good quality product.

[0006]

In order to achieve the above object, the present invention forms a molded article having the same shape as a product, assembles them in a tree shape, applies a coating, and then forms the molded article. In an assembly for precision casting in which a product is cast in place of a metal, the assembly is formed by branching from a gate to a plurality of molded product connecting portions, and a projection is formed at a branch portion between the gate and each molded product connecting portion. Is formed.

[0007]

According to the assembly for precision casting of the present invention, the convex portion formed at the branch portion between the sprue portion and the connecting portion of each molded product has an empty space for the pool when the molten metal is poured into the mold. This prevents a part of the molten metal injected from the gate from directly entering the product space through the inner wall of the runner.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIGS. 1 and 2 show an example of a wax assembly. This wax assembly A has a funnel-shaped gate section 10.
Are formed on the upper portion of the horizontal member (branch portion) 11, and four quadrangular prism-shaped molded product connecting portions 12 are arranged at equal intervals below the horizontal member 11, and a pair of outer molded product connecting portions are provided. 12
On the other hand, two sets of handling support portions 13 are protrudingly provided, and a ring-shaped convex portion 14 is formed on the outer periphery of the sprue portion 10, while the sprue portion 10 and the A protrusion 15 is provided between the pair of outer molded product connecting portions 12.
Are formed, and projections 16 are formed at the distal end of each of the molded article connecting portions 12 so as to face each other. Further, a metal attachment 1 is formed from an end of the gate 1.
7 are protrudingly provided, and furthermore, a metal round bar (support fitting) 18 is inserted through a tip end of each molded product connecting portion 12 so as to be roughly configured. And the gate section 10 and the horizontal member 1
1, molded article connecting portion 12, support portion 13, convex portion 14, convex portion 1
5 and the projections 16 are integrally formed by wax, while the metal attachment 17 and the round bar 18 are inserted into a mold by insert molding to insert the wax gate portion 10, the horizontal member 11, and the molded product connecting portion 12. , The support portion 13, the convex portion 14, the convex portion 15, and the protrusion 16 are formed at the same time as the molding. Also,
A paraffin (lubricant) 19 is attached to the round bar 18 of the wax assembly A by spraying.

[0010] Wax assembly A constructed as described above
In this case, a wax molded product having the same shape as a product that has been separately injection-molded is welded to the front and back surfaces of the four molded product connecting portions 12. In this state, the slurry is transported using the upper portion of the attachment 17, and the ceramic slurry and the refractory particles are alternately attached around the wax assembly A to form a coating layer and dry (coating step). Subsequently, the wax assembly A in the coating layer (mold) is melted, the mold is inverted, and the melted wax is taken out from the gate section 10 (dewaxing step). Further, after firing the mold, a molten metal (molten metal) is poured into the mold to be cooled and solidified, and then the mold is removed to separate the product.

In this way, the production of precision cast products by the lost wax method is performed smoothly. In this case, in the wax assembly A, since the protrusions 16 are formed at the tip end of each molded article connecting portion 12 so as to be opposed to each other, in the coating step, the application of the ceramic slurry and the refractory particles are performed. When spraying is repeated several times (4 to 5 times), as shown in FIG. 3, the coating layers C adhered to the respective protrusions 16 are connected to each other, so that the molded article connecting portions 12 are connected to each other. Even if the coating layer C becomes heavy, it supports each other, so that each molded article connecting portion 12 does not bend due to its own weight during handling for forming the coating layer by a robot or the like. Further, since the ring-shaped convex portion 14 is formed on the outer periphery of the gate section 10, during coating, as shown in FIG. The particles adhere and the coating layer C is thickened to reinforce the coating layer C of the gate section 10, and therefore, the wax of the gate section 10 and the metal attachment inserted into the gate section 10 in the dewaxing process. Even if the funnel 17 has a large thermal expansion, the coating layer C of the gate section 10 does not crack. Furthermore, paraffin (lubricant) is added to the round bar 18.
Since the adhesive 19 is attached, at the time of heating after the coating step, the paraffin 19 is melted and the space between the round bar 18 and the coating layer C is easily slid, and accordingly, the thermal expansion of the round bar 18 follows. The coating layer C is prevented from being forcibly pulled, and cracks do not occur in the coating layer C (see FIG. 3). Furthermore, since convex portions 15 are respectively formed between the sprue portion 10 and the pair of outer molded product connecting portions 12 on both surfaces of the horizontal member 11, as shown in FIG. The convex portion 15 serves as a basin S1 for the pool when the molten metal is injected into the mold C, so that a part of the molten metal injected from the sprue portion is formed by the runner portion (the horizontal member 11 and the molded product connecting portion 12). Is prevented from traveling along the inner wall of the empty space after the wax has escaped) and directly entering the product empty space S2. The molten metal is filled in order from the bottom, so that a high-quality product can be obtained without causing defects in the product.

[0012]

As described above, according to the present invention, a molded article having the same shape as a product is formed, these are assembled in a tree shape, coated, and then the molded article is replaced with a metal to replace the product. In an assembly for precision casting to be cast, the assembly is formed by branching from a gate to a plurality of molded article connecting portions, and a convex portion is formed at a branch portion between the gate and each molded article connecting portion. Therefore, the convex portion formed at the branch portion between the gate portion and each molded product connecting portion serves as a basin for the pool when the molten metal is poured into the mold, and a part of the molten metal injected from the gate portion. Can be filled in the product cavities sequentially and all at once by preventing the infiltration of the molten metal directly into the product cavities by traveling along the inner wall of the runner.
A defect can be prevented from occurring in the product near the gate of the runner, and a product of good quality can be stably obtained.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is an explanatory view showing an example of a tip end of a molded article connecting portion.

FIG. 4 is an explanatory view showing an example of a gate section.

FIG. 5 is an explanatory view showing an example of a vacant space for a pool;

FIG. 6 is a front view showing a conventional wax assembly.

[Explanation of symbols]

 A Wax assembly (Precision casting assembly) 10 Gate 11 Horizontal member (branch) 12 Molded product connection 15 Convex place

Claims (1)

(57) [Claims] 1. A precision casting assembly for molding a product having the same shape as a product, assembling the product into a tree shape, applying a coating, and then casting the product by replacing the molded product with metal. An assembly for precision casting, wherein the assembly is formed by branching from a portion into a plurality of molded product connection portions, and a projection is formed at a branch portion between the gate section and each of the molded product connection portions.