JPS6380941A - Casting method - Google Patents

Abstract

PURPOSE:To obtain precision casting parts having high quality at a low cost by subjecting both a rubber mold and product master to templating of a master surface to form split gypsum molds and pouring a molten metal into the split gypsum molds, thereby forming a casting product. CONSTITUTION:The product master 1 is disposed in a molding flask 2 and liquid rubber for templating is poured into the gap part of the molding flask 2 and is cured to form a rubber block 10 embedded with the product master 1. The block 10 is then taken out of the flask 2 and the master 1 is taken out. The rubber molds of a cavity mold 11 and a core mold 11 are thus formed. The molds 11 and 12 are then mated and rubber liquid is poured into the cavity part and is cured to form the rubber master 13. The core mold 11 is held stuck with the master 13 and is housed in this state into the flask 2. A gypsum soln. is poured into the flask 2 and is cured to obtain a cavity 14 of the gypsum mold. After a core mold 15 of the gypsum mold is obtd. said mold is coupled via a parting plane to the cavity 14 of the gypsum mold. The molten metal is poured into the cavity part and is cooled to solidify. The casting 16 is thus obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a metal casting method, and particularly to a gypsum casting method for obtaining a precision cast product with a smooth casting surface and high dimensional accuracy.

(Prior Art) A gypsum casting method using a gypsum mold is widely used as one of the so-called precision casting methods for obtaining a precision cast product with a smooth casting surface and high dimensional accuracy.

As a plaster casting method, the plaster molding method, which uses a vanishing model to form a block-shaped plaster mold, has been widely used for a long time, but this method requires a lot of cost for molds and man-hours for molding the vanishing model. Furthermore, there are drawbacks such as the fact that when the model disappears, the mold tends to crack due to thermal expansion of the model, and it is difficult to cast large parts.

As a plaster casting method that eliminates the drawbacks of the plaster molding method described above, a method using a split mold as shown in FIGS. 5 to 8 has been conventionally adopted.

As shown in FIG. 5, this casting method is carried out by first forming a rubber mold by molding the surface of the product master while defining the parting surface using molding rubber.

As shown in FIG. 5(a), the product master l is placed in the formwork 2 with a parting surface appropriately defined using a thin metal plate or the like (not shown) according to the product shape, Liquid rubber for mold making is injected into the cavity of the mold 2 and hardened to form a rubber mold 3 in which the la side of the product master 1 is molded.

The product master 1 is attached to the rubber mold 3 as shown in FIG. 5(b). The product was stored in the formwork 2 in an inverted state, and after applying a mold release agent to the parting surface 3a, the liquid rubber for molding was again injected into the formwork 2 and hardened, and the product master 1 Ia was molded. Form mold 4.

Figure 5 (C) shows a rubber mold formed by molding the surface shape of the cavity side and core side of the product master while defining the parting surface as described above, and dividing it at the parting surface and removing the product master. Indicates the condition.

Next, as shown in FIGS. 6(a) and (b), the rubber mold 3
．． 4 are housed in the mold frame 2 and inverted molds are made using liquid rubber for mold making to form rubber molds of a core mold 5 which is the inverted cavity mold 3 and a cavity mold 6 which is the inverted core mold 4. .

Subsequently, as shown in FIGS. 7(a) and 7(b), after the rubber molds 5 and 6, which have been inverted and molded, are each housed in a mold 2, a gypsum solution is injected into the mold and hardened, and a cavity mold 7 is formed. and form a plaster mold of core mold 8.

Finally, as shown in FIG. 8, the gypsum-shaped cavity mold 7 and the core mold 8 are combined via the parting surface, and the molten metal is poured into the cavity and cooled and solidified to obtain a cast product 9.

(Problems to be Solved by the Invention) In the conventional plaster casting method using a split mold as described above, in the process of forming a plaster mold, the rubber mold that has been molded once is inverted and molded again. This increases manufacturing man-hours and consumes a large amount of expensive mold-making liquid rubber, and it is extremely complicated to determine the parting surface when making a mold using the product master mold-making liquid rubber. However, since the parting surface is smooth, it is very difficult to match the cavity mold and core mold of the plaster mold.

In view of the current situation as described above, the present invention was devised as a result of intensive studies to develop a casting method using a split gypsum mold that eliminates the drawbacks of the prior art.

(Means for Solving the Problem) That is, the present invention creates a rubber mold by dividing a rubber block formed of liquid rubber for mold making and having a product master embedded in the center thereof along the parting surface of the product master. If necessary, use the rubber mold to form a rubber master with a casting rubber liquid, and define the parting surface based on the rubber mold and the rubber or product master while forming the master surface. This casting method is characterized by forming a divided plaster mold by making a mold, and injecting molten metal into the cavity of the divided plaster mold and cooling and solidifying it to form a cast part.

(Function) The present invention is constructed as described above, and its function is to form a rubber mold by dividing a rubber block in which a product master is embedded in the center along a parting surface set according to the shape of the product master. This makes it possible to immediately form a plaster mold without having to form an inverted rubber mold again as in the prior art, and it also becomes possible to easily define the parting surface by dividing the rubber block, and this dividing surface has unevenness. Because of the shape, mold matching can be done accurately and easily.

(Embodiment) An embodiment of the present invention is as shown in FIGS. 1 to 4,
Fig. 1 shows the method of forming a rubber mold. First, Fig. 1(a)
As shown in the figure, with the product master l placed in the center of the mold 2, a mold-making liquid rubber such as silicone rubber was injected into the void of the mold 2, and the product master l was buried in the center. A rubber block 10 is formed.

Next, the rubber block 10 is taken out from the mold 2 and cut along the parting surface that matches the product shape using a sharp cutting tool such as a surgical scalpel, and the product master l is taken out, as shown in FIG. 1(b). Capity type 11 and core type 12
Molded with a rubber mold.

Although FIG. 1(b) shows an example in which the rubber block 10 is divided into two to form a rubber mold, the number of divisions can of course be set to any nine lines depending on the shape of the product. Furthermore, by intentionally cutting the rubber block 10 with a cutting tool while creating excessive unevenness, a parting surface is formed that allows accurate and easy mold matching when combining a plurality of divided molds. Ru.

Next, as shown in FIG. 2, the rubber molds 12 and 12 are combined, and a molding rubber liquid such as silicone rubber or polyurethane rubber is injected and hardened into the cavity to form a rubber master 13.

The reason why the product master l is converted into the rubber master 13 using the rubber molds 11 and 12 in this way is that the master is flexible when it is removed from the plaster mold later when the plaster mold is formed. Although this is preferable, the product master is generally made of a material with poor flexibility, such as metal or plastic deck.

Therefore, if the product shape is extremely simple and the product master can be easily removed from the plaster mold, or if the product master is made of a highly flexible material, the process of forming a rubber master as described above is unnecessary. It is.

Next, the process of forming a plaster mold will be explained based on Figure 3.
First, as shown in FIG. 3(a), the core mold 11, which is one of the divided rubber molds, is housed in the mold frame 2 with the rubber master 13 attached to the upper surface. A gypsum solution is injected and hardened to define the parting surface by the rubber mold 11, and a gypsum-shaped cavity mold 14 is obtained by molding the surface 13a of the rubber master 13.

Next, as shown in FIG. 3(b), the rubber mold 11 is removed from the state shown in FIG. 3(a), and the plaster-shaped cavity mold 14 is placed in the formwork 2 with the rubber master 13 attached to the top surface. By injecting and hardening a gypsum solution into the mold 2, a parting surface is defined by the mold 14 of the gypsum mold, and 13 of the rubber master 13 is formed.
A plaster-shaped core mold 15 is obtained by molding the b-side.

Next, as shown in FIG. 3(C), the gypsum-shaped cavity mold 14 and core mold 15 formed as described above are taken out from the mold and divided at the parting surface to form a rubber master 1.
Let 3 leave.

At this time, as mentioned above, since the rubber master 13 is highly flexible, it is possible to remove the plaster mold without damaging it at all, no matter how complicated the shape.

Finally, as shown in Fig. 4, a plaster-shaped cavity mold 14 is formed.
and the core mold 15 through the parting surface, and the molten metal is poured into the cavity and cooled and solidified to obtain the cast product 16.

(Effects) The present invention has the above-mentioned configuration and operation, and its effects are that, no matter how complicated the shape of the part, it is possible to easily define the parting surface and form appropriately divided plaster molds. This makes it possible to provide high quality precision cast parts at low cost.

[Brief explanation of the drawing]

1 to 4 show examples of the present invention, in which FIG. 1 shows a rubber mold, FIG. 2 shows a rubber master, and FIG. 3 shows a plaster mold.
Figure 1 shows each manufacturing method of cast parts. Figures 11 and 5 to 8
The figure shows a conventional casting method.

Claims (1)

[Claims] A rubber block with a product master embedded in the center made of liquid rubber for mold making is divided along the parting surface of the product master to form a rubber mold, and the rubber mold is used to perform pouring as necessary. A rubber master is formed using a mold rubber liquid, and a parting surface is determined based on the rubber mold and the rubber or product master, and the surface of the master is molded to form a gypsum division mold, and the gypsum division is performed. A casting method characterized by injecting molten metal into a mold cavity and cooling and solidifying it to form a cast part.