JPH07323349A - Manufacture of lost wax pattern - Google Patents

Abstract

PURPOSE:To dispense with an adhering process of a split lost wax pattern by integrating the cylindrical lost wax pattern in a straight manner, simplify the forming work of this lost wax pattern, and provide the lost wax pattern of a plurality of kinds where the forming pattern of the lost wax pattern is one kind with different curvature by selecting the bending degree of the lost wax pattern. CONSTITUTION:In a manufacturing method of a lost wax pattern, a cylindrical lost wax pattern 20 is formed straight, and bent in the prescribed curved shape, and held. In this condition, the molding agent 30 is filled into at least one of a hollow part and an outer circumferential part of the lost wax pattern 20, and this molding agent 30 is solidified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a curved tubular vanishing model.

[0002]

2. Description of the Related Art As a method for manufacturing this type of disappearance model,
For example, the technique disclosed in Japanese Patent Laid-Open No. 64-40139 can be mentioned. According to the technique of this publication, a cylindrical vanishing model curved by Styrofoam is divided into upper and lower parts and individually molded, and these are joined together in accordance with a separately molded core, and the mutual joint surfaces are bonded by an adhesive liquid. It is glued. The core is used in order to prevent the vanishing model from being deformed before its use.

[0003]

The above-mentioned prior art requires a step of adhering vanishing models formed by being divided into two parts, and in order to form vanishing models having different curvatures, the respective curvatures are formed. Each model must have a mold for molding. The problem to be solved by the present invention is to eliminate the step of adhering a disappearing model divided by integrally molding a disappearing model in a cylindrical shape, simplify the molding work of this disappearing model, and By selecting the bending degree, it is possible to provide a plurality of types of vanishing models having different curvatures even if one type of vanishing model forming die is used.

[0004]

In order to solve the above-mentioned problems, a method for manufacturing a vanishing model according to the present invention is designed such that a tubular vanishing model is straightly shaped and then bent and held in a predetermined curved shape. The method is characterized in that the molding material is filled in at least one of the hollow portion and the outer peripheral portion of the disappearing model to cure the molding material.

[0005]

According to the above-mentioned method, a molding material is filled in the hollow portion or the outer peripheral portion of the vanishing model which is bent and held in a predetermined curved shape and hardened, so that the curved shape according to the request can be obtained. An extinction model is created. In the first step, the lost model may be molded straight, so that the work of dividing the two models and joining the models can be omitted, and the molding operation can be simplified. Further, by selecting the bending degree of the vanishing model formed straight, it is possible to make a plurality of types of vanishing models having different curvatures from the vanishing model formed by one type of mold. Further, by cutting one straight-shaped vanishing model into a predetermined length, it can be used as a plurality of vanishing models.

[0006]

Embodiments of the present invention will now be described with reference to the drawings. Example 1 FIG. 1 is an explanatory view showing the manufacturing process of the disappearance model 20.
First, as shown in FIG. 1 (A), a disappearing model 20 having a tubular shape is formed straight by a mold 10 for a model. That is, since the disappearance model 20 is straight, the mold 1
0 is a slide mold 16 on the upper mold 12 and lower mold 14
By adding the, the tubular disappearance model 20 can be integrally molded without being divided. As is well known, the disappearance model 20 is formed by using styrofoam or the like, and the disappearance model 20 and the molten metal are exchanged at the time of casting to cast a tubular product. The product to be cast is, for example, a pipe forming an engine intake manifold or an exhaust manifold.

As shown in FIG. 1 (B), both ends of the extinguishing model 20 formed straight are held by chucks 24 as shown in FIG. 1 (C), and the extinguishing model 20 is bent into a predetermined curved shape. It holds in its shape. Chuck 2
4 may be added according to the required curved shape or the like. Next, as shown in FIG. 1 (C), one open end of the disappearing model 20 held in a curved shape is closed with a breathable lid 26, and sand and a binder are introduced from the other open end. The molding material 30 mixed with is put in the hollow portion of the disappearance model 20. When the molding material 30 is filled in the hollow portion,
The molding material 30 is cured while maintaining the curved shape of the disappearance model 20. As a result, even if the chuck 24 is removed, the disappearing model 20 is kept in a curved shape.

Since the disappearing model 20 after the molding material 30 has been hardened is held in a predetermined curved shape without the need for restraint by the chuck 24 or the like, it corresponds to a portion other than the pipe of the intake manifold, for example. It is possible to join a model (not shown) to make a vanishing model of the entire intake manifold. Further, in the present embodiment, the molding material 30 is filled in the hollow portion of the disappearing model 20 before joining the disappearing model 20 with other related models.
Even if the disappearance model 20 is thin, the molding material 30 can be easily attached,
And it is possible to fill it uniformly.

Embodiment 2 FIG. 2 shows another embodiment for holding the vanishing model 20 in a predetermined curved shape. In this embodiment, the disappearing model 20 is set in a state of being bent into a predetermined curved shape with respect to the upper mold 40, and the upper mold 40 and the lower mold 42 are matched with each other. In this state, the hollow portion of the disappearing model 20 is filled with the molding material 30 by the same means as in the case of the first embodiment, and the inside of the lower mold 42 is opened by using the opening (not shown) of the upper mold 40, That is, the outer peripheral portion of the disappearance model 20 is also filled with the molding material 30. After that, when the molding material 30 in the hollow portion and the outer peripheral portion of the disappearing model 20 is cured, the disappearing model 20 is held in a predetermined curved shape by the molding material 30 in the hollow portion and the outer peripheral portion. Therefore, the disappearing model 20 can be taken out from the lower mold 42 together with the cured molding material 30. Therefore, it is possible to set the disappearance model 20 together with the molding material 30 in a casting mold (not shown) and perform casting.

In the second embodiment, a plurality of vanishing models 20 having different curvatures with respect to the upper die 40 and the lower die 42 are used.
By setting and curing the molding material 30 as described above, it is possible to simultaneously hold each vanishing model 20 in each curved shape. In the second embodiment, the molding material 30 is filled and cured only in the outer peripheral portion of the disappearing model 20, and the curved shape of the disappearing model 20 is sufficiently maintained even if the filling of the molding material 30 into the hollow portion is omitted. . However, it goes without saying that the molding sand is filled in the hollow portion of the disappearing model 20 during casting.

Third Embodiment FIG. 3 shows an example in which the second embodiment is further modified. In this third embodiment, as shown in FIG. 3 (A), the elastic member 46 made of a material such as silicone rubber is inserted into the hollow portion of the disappearing model 20 in a straight state. Then, both ends of the elastic member 46 are set in the upper mold 40 having the same configuration as in the second embodiment, and the disappearing model 20 is bent and held in a predetermined curved shape. Thereafter, the upper mold 40 and the lower mold 42 are matched with each other as in the second embodiment, and the molding material 30 is filled inside the lower mold 42, that is, the outer peripheral portion of the disappearing model 20. After curing the molding material 30, the elastic member 46 disappears
Remove from Also in this third embodiment, each vanishing model 20
Can be taken out from the lower mold 42 together with the cured molding material 30 and set in a casting mold as it is for casting.

By bending the disappearing model 20 with the elastic member 46 inserted in the hollow portion as described above, it is possible to accurately bend even when the disappearing model 20 is required to have a delicate curved shape. It is the same as the above case that the molding sand is filled in the hollow portion of the disappearing model 20 after the elastic member 46 is pulled out at the time of casting.

In each of the above embodiments, the shape of the disappearing model 20 is not limited to a cylinder, but may be a rectangular cylinder. Further, even if there is a protrusion or the like on a part of the outer periphery of the disappearance model 20, the above-described technique can sufficiently cope with the position of the protrusion.

[0014]

According to the present invention, a tubular disappearance model is formed straight and then bent into a predetermined curved shape.
Unlike the prior art, in which the disappearing model formed by dividing into two pieces is bonded later, the forming work of the disappearing model is simplified and by selecting the bending degree of the disappearing model formed straight, Even if only one die of the vanishing model is used, a plurality of vanishing models having different curvatures can be made.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a manufacturing process of a vanishing model according to a first embodiment.

FIG. 2 is a cross-sectional view showing a second embodiment.

FIG. 3 is an explanatory diagram showing a manufacturing process of a vanishing model according to a third embodiment.

[Explanation of symbols]

 20 Disappearance model 30 Molding material

Claims (1)

[Claims] 1. A tubular disappearance model is formed straight, then bent and held in a predetermined curved shape, and in this state, at least one of a hollow portion and an outer peripheral portion of the disappearance model is filled with a molding material, and this molding is performed. A method for manufacturing an extinction model, which comprises curing a material.