JPS5985346A - Pattern for casting mold - Google Patents

Abstract

PURPOSE:To enable easy manufacture of a pattern for a casting mold having an intricate shape in the stage of manufacturing said pattern for casting a member having an intricate three-dimensional curved surface by disposing a core material in a pattern body made of a flexible material and making the core material removable in the stage of forming a sand mold. CONSTITUTION:A pattern 2 for a casting mold provided with an intricate three- dimensional curved surface for casting a pump impeller, etc. is manufactured by constituting the pattern 2 together with a freely removable core material 4 in a pattern body consisting of a flexible material such silicone rubber. A plate material made of a mild steel, lead alloy or plastic is used as the material 4. The material 4 is first removed after molding of a sand mold for casting and the body 3 is removed in succession, in the stage of forming said sand mold by using such pattern 2. Since the body 3 is made of the flexible material, said body shrinks by as much as the volume corresponding to the space made after the removal of the material 4; moreover, it deflects and therefore the pattern is extremely easily removed from the sand mold and the breakage of the sand mold is obviated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a casting mold model for casting a member having a complicated three-dimensional curved surface, such as a pump impeller having three-dimensionally shaped blades.

Conventional mold models are made of wood, resin, metal (for example, aluminum alloy), and are characterized by being resistant to deformation.

For this reason, when manufacturing molds for products with complex shapes, especially those with three-dimensional curved surfaces or inverted slopes, the mold parts obtained from the mold model, which is formed by dividing the mold, are assembled into a single mold. The mold model itself can be divided into multiple parts, and after the mold is formed, the mask of the mold model is removed and the parts are divided (wooden mold).
I had no choice but to do so.

However, according to the former type, ■ It is extremely difficult to make a model.

■ It takes a lot of time to assemble the divided molds.

■ Burrs occur on the mating surfaces of the mold, making it difficult to finish.

■ Errors when assembling the mold lead to a decrease in accuracy.

■ Casting defects such as sand traps are likely to occur during repairs during mold assembly.

There were other problems.

In addition, according to the latter (made wooden mold), there was a patent that required a large amount of man-hours and time to make the model, and required advanced technology to maintain its accuracy.

FIG. 1 is a perspective view showing an example of a core mold for molding a pump impeller having three-dimensional blades. Core type IFi, divided core type 1 divided into each fluid passage formed by the front and back surfaces of the blade and the main side plate of the impeller
1L, 1b, 1'c, 1d.

It has a structure in which ...... are combined and integrated according to the number of blades.

In this case, the number of impeller blades is often an odd number in order to prevent pump pulsation and vibration.In this case, due to problems in assembling the core, the single split core of the odd number of blades is divided into two. Otherwise, assembly would be impossible, so the number of core divisions would be even greater. The model for making this split core mold is usually made using a wooden mold, which is divided at the wing surface, making it difficult to make a wooden mold and requiring many man-hours even for experienced workers.

In addition, when assembling the core mold, use a surface plate or an assembly jig, and pay attention to the equal placement of the wings and adjustment of the level, to prevent deformation of the split core mold when setting the core mold. To prevent this, strong tightening required skilled work. Furthermore, this work involves making holes in a part of the mold and making corrections, and since the mold is moved or handled each time, the split core molds may come into contact with each other and be damaged, resulting in casting problems such as sand molds. Easy to cause defects.

Moreover, in the products cast by the above-described method, a large number of cracks occur on the mating surfaces of the split core molds, and a large number of man-hours are required for subsequent processing.

The present invention provides a mold model that solves all of the above-mentioned problems, and the interior of the flexible model body is formed of a removable core material, and the bare wire can be deformed by removing the core material. It is characterized by the following.

Next, the mold model of the present invention will be explained with reference to the drawings.

FIG. 2 shows a perspective view of an example of a mold model for casting a pump impeller as an embodiment of the mold model of the present invention, and FIG.
The figure is illustrated by a sectional view taken along the line ■--■ in FIG. As shown in the drawing.

In the mold model 2 of the present invention, the interior of a model body 3 made of silicone rubber as a flexible material is formed by a removable core material 4.

As the core material 4, a plate or bar material of mild steel, lead alloy, plastic, etc. is used depending on the shape and size of the mold model 2.

The model body 3 and the core material 4 can be used as one body with the core material 4 sandwiched in the model body 3 in a sandwich-like structure, or the core material 4 can be used tightly inside the model body 3 with a medium-sized structure. or a composite structure of both of the above.

Next, the function of the mold model of this invention will be explained.

The mold model 2 is oriented so that the core material 4 can be easily removed during sand mold molding, and after the sand mold molding, the core material 4 is first extracted, and then the model body 3' is pulled out. At this time, the model body 3 shrinks and bends by a volume corresponding to the space through which the core material 4 has been removed, so that it can be removed very easily.

Silicone rubber or the like is suitable for the model body 3 in terms of moldability and mold release properties.

As is clear from the above description, even if the mold model of the present invention is a mold for casting a member having a complicated three-dimensional curved surface, it can be easily molded as an integral mold, and It offers many excellent industrial advantages, such as being able to handle complex shapes even as child models.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an example of a conventional core mold, FIG. 2 is a perspective view showing an embodiment of the mold model of the present invention, and FIG.
It is a sectional view taken along line nn in the figure. In the drawings, 1... Conventional core mold, 1a, 1b, 1c, 1d=divided core mold, 2... Mold model of the present invention, 3... Model body, 4... Core material. Applicant Ebara Corporation Agent Natsuo Shioya (and 2 others) Figure 2 1 Figure 3

Claims (1)

[Claims] 1. A casting mold characterized in that the interior of a flexible model body is formed of a removable core material, and the bare wire can be freely deformed by removing the core material.