JPH02220731A - Mold manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a mold used in precision casting of a product having a complicated shape and having recesses.

(Prior Art) Conventionally, it is known that molds used in precision casting are manufactured by a method such as that described in Japanese Patent Application Laid-Open No. 58-157547, for example. In the method of manufacturing this type of mold, first, a disappearing model is molded using a mold for molding the model. Next, a refractory slurry is applied to the model, and then a refractory made of particles or powder is applied to the model to which the slurry has been applied, and then it is dried. Here, the slurry is attached.

The steps of coating and drying the refractory are repeated several times starting from the smallest particles of the refractory. As a result, the surface of the model is coated with a refractory material having a required thickness and having a multilayered structure and increased strength. Thereafter, the model was dissolved and disappeared, and a mold was obtained using the refractory material covering the model.

However, for example, if a mold used for precision casting of a complex-shaped product with recesses is manufactured as described above, it is difficult to sufficiently fill the recesses with refractory material in the recesses of the model of the product. In addition, it is difficult to form each layer of refractory to be coated with a uniform thickness, and it is also difficult to obtain the required thickness. It is difficult to apply. The refractory covering the concave parts of the model will form a convex part corresponding to the concave part in the mold after the model has disappeared, but if the convex part is not molded into a predetermined shape, the concave part of the product will If the shape of the refractory cannot be obtained with high accuracy and the thickness of each layer of the refractory is not uniform, there is a problem that sufficient strength cannot be obtained in the convex portion.

(Problems to be Solved by the Invention) An object of the present invention is to provide a mold manufacturing method for manufacturing a highly accurate mold capable of reliably molding the recessed part of a product having a recessed part, in order to eliminate such inconveniences. With the goal.

(Means for Solving the Problems) In order to achieve the above object, the present invention molds a disappearing model of a product having a recessed part using a model molding die, coats the surface of the model with a refractory material, and then In the method of manufacturing a mold by making a model disappear, a core having a convex part having a shape corresponding to the concave part of the product is disposed in the mold, and then the mold is filled with a disappearing model material to make the model. Then, the model integrated with the core is removed from the cough mold, the model and the core are coated with a refractory material, and the disappearing model material part of the model disappears to remove the refractory material. and a core.

(Function) By this means, a core having a convex portion having a shape corresponding to the concave portion of the product is provided in advance in the model molding die, and the cough mold is filled with disappearing model material to form the model. mold. Then, the model is molded integrally with the core, and the model is taken out from the mold. Subsequently, a refractory coating is applied to the surface of the model together with the core. Thereafter, when the disappearing model material portion of the model disappears, the refractory covering the model and the core are left together to form a mold.

(Embodiment) An embodiment of the present invention will be described in sequence according to FIGS. 1 to 4.

The product A to be cast in the mold manufactured in accordance with this embodiment is generally ring-shaped, as shown in cross-section in FIG. 5, and has a recess a on the inner periphery of its center.

When manufacturing a mold according to this embodiment, first, as shown in FIG. 1, a substantially ring-shaped core 2 is placed in a model molding mold 1 which is formed to be able to be divided into upper and lower parts. cough middle child 2
is made of silica sand, which is core sand, and is made of a caking agent such as resin, clay, or bentonite. Further, the core 2 has a convex portion 3 on its outer periphery, and the shape of the convex portion 3 corresponds to the shape of the concave portion a of the product A. The cough mold 1 has a hollow part 4 shaped like a product A in which the core 2 is placed.

Next, a melting model material such as hot-melting wax or plastic is press-fitted into the mold 1 configured as described above in a molten state, and after solidifying the disappearing model material in the mold 1, the melting model material is The mold 1 is divided into upper and lower parts and the product model 5 is taken out. At this time, the product model 5 is taken out from the mold 1 while the core 2 remains integrated with the product model 5, and as shown in FIG. A model 7 is formed by joining the models 6 together.

Next, as shown in FIG. 3, a refractory slurry 8 is applied to the model 7 in which the core 2 is integrated to adhere particle or powder refractories 9, and then dried. Refractory 9
Apply a coating. Here, slurry 8. The application and drying of the refractory material 9 is repeated several times to form a multilayer coating of the refractory material 9 on the surface of the model 7.

Subsequently, the disappearing model material part of the product model 5 of the model 7 and the sprue model 6 are melted and disappear. As a result, as shown in FIG.
form 0. The mold 10 has a shape that molds the recess a of the product A, and includes the protrusion 3 of the core 2 to form a product cavity.

As a result, the product cavity b corresponding to the recess a of the product A is formed by the protrusion 3 of the core 2, as in the prior art, so the recess a is molded with high precision.

Then, the sprue portion C is attached to the mold 10 manufactured as described above.
The cast product obtained by pouring molten metal is released from the mold 10, the part corresponding to the sprue C is cut, and the core 2
is removed by shot blasting or the like to obtain Product A.

(Effects of the Invention) From the above, according to the mold manufacturing method of the present invention, in the mold to be formed, the shape of the convex part for forming the concave part of the product can be formed with high precision by the core. This has the effect that a highly accurate mold that can reliably mold the recessed part of a product having a recessed part can be easily manufactured.

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view of a mold for molding a model, FIG. 2 is an explanatory sectional view of a model, and FIG. 3 is an explanatory sectional view of a refractory coating.
FIG. 4 is an explanatory sectional view of the mold, and FIG. 5 is a sectional view showing the product in the example. ■...Mold for model forming, 2... Core, 3... Convex portion, 5... Model, 9... Refractory material,
10... Mold, A... Product, FIG, 1 FIG, 2 a... Recess. FjG, 4

Claims (1)

[Claims] 1. In a method of manufacturing a casting mold by molding a disappearing model of a product having a concave part in a model mold, coating the surface of the model with a refractory material, and then making the model disappear, the concave part of the product After disposing a core having a convex portion of a shape corresponding to the shape in the mold, the mold was filled with disappearing model material to form a model, and then integrated with the core from the mold. The method is characterized in that the model is taken out, the model and the core are coated with a refractory material, and the disappearing model material part of the model is made to disappear to produce a mold composed of the refractory material and the core. Mold manufacturing method