JPH0515943A - Production of mold - Google Patents

Abstract

PURPOSE:To manufacture a mold at a low cost by shifting aggregation of molding sand to an opening hole at one side, removing the molding sand projected from a flask, abutting a pattern plate having the prescribed cavity on an opening hole at the other part and filling the molding sand between the pattern plate and the aggregation. CONSTITUTION:The aggregation S of molding sand in the flask 1 for upper and lower molds taking out a casting product W, is shifted toward the opening hole at one side in the flask 1. The molding sand shifted and projected from the flask 1 is removed and the pattern plate 2 having outer shape of the prescribed cavity C is abutted on the opening hole at the other part in this flask 1. After filling the molding sand between the pattern plate 2 and the aggregation, this pattern plate 2 is removed to manufacture the aggregation of molding sand having the prescribed cavity C in the flask 1. By this method, consumption of the molding sand is a little and the mold can be manufactured at a low cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold manufacturing method, and more particularly to a mold manufacturing method which can be manufactured at low cost.

[0002]

2. Description of the Related Art Conventionally, a mold made of foundry sand has been reused but not reused, that is, after pouring once to obtain a foundry product. The mold is crushed, and the molding sand is separated and purified for reuse.

[0003]

However, since the above-mentioned conventional mold is made from the beginning every time a casting product is obtained, there is a drawback that the manufacturing cost of the mold becomes high. For example, when a mold is made by the cold box method and hot water such as Al is poured into the cavity (mold cavity) of the mold to manufacture a predetermined casting product, the mold after the casting product is taken out from the cavity is crushed. The sand is then screened and the sand is reused, but the mold from which the casting was removed has not been reused.

If it is attempted to reduce the cost by reusing the mold from which the casting has been taken out as it is, the cavity surface from which the casting is taken out is rough and it is impossible to obtain a desired casting product. Is.

Therefore, the present invention has been made to solve the above-mentioned drawbacks, and an object thereof is to provide a mold manufacturing method by which most of the mold can be reused to obtain a mold at low cost. To do.

[0006]

In order to achieve the above-mentioned object, the method of the present invention provides a method for forming an aggregate of foundry sand in an upper and lower open type frame body from which a cast product is taken out, by opening one side of the frame body. To remove the foundry sand that has been moved and protruded from the frame body, abutting a model plate having the outer shape of a predetermined cavity to the other opening of the frame body, the model plate and its assembly After the molding sand is filled in the gaps, the model plate is removed to form an aggregate of the molding sand having a predetermined cavity in the frame body.

[0007]

The aggregate of foundry sand in the frame body from which the cast product is taken out is moved toward one opening of the frame body, and the foundry sand protruding from the frame body is removed. Then, a model plate having an outer shape of a predetermined cavity is brought into contact with the other opening of the frame body, and molding sand is filled in a gap between the model plate and the aggregate. After that, when the model plate is removed, an aggregate of foundry sand having a predetermined cavity in the frame is obtained.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a process diagram showing an example method, in which each process other than the process (f) is shown in a vertical section.

On the step (a), the lower open frame 1 is placed on the model plate 2 having the outer shape of the cavity C (see step (b)).
Then, a blowing frame 3 having a blowing nozzle 3a is attached above the frame 1, and the resin sand is injected into the frame 1 along with the compressed air through the blowing frame 3. The resin sand injected into the frame 1 is hardened to form an aggregate S of foundry sand (resin sand).

Step (b) The model plate 2 and the blowing frame 3 are removed from the frame body 1 to form a mold (upper mold) A having a cavity C.

Step (c) The upper die A and the lower die B are joined, and Al hot water is poured into the cavity C from a hot water passage (not shown). Casting product W after Al solidifies
Is obtained. The lower mold B may also be a mold obtained by the method of the present invention.

Step (d) The upper die A and the lower die B are separated, and the casting product W is taken out from the cavity C.

Step (e) The mold A (frame 1) from which the cast product W has been taken out has a flat upper portion and has the same cross-sectional shape as the cross-sectional shape of the inside of the frame 1, and the height of the frame 1 is high. It is mounted on a pedestal D having a protrusion D'having a height smaller than the height, for example, about 1/4.

Step (f) This step (f) corresponds to the plan view of step (e). In this step (f), the assembly member of the frame body 1 is once removed and expanded to the position shown by the chain line 1 '. Then, the frame body 1 is reassembled at the position where the lower end of the frame body 1 comes into contact with the pedestal D.
As a result, the upper portion S ₀ of the resin sand aggregate S projects from the upper surface of the frame 1.

Step (g) The upper portion S ₀ of the aggregate S is cut off by the cutter 4, and then the hole 5 reaching the lower end of the aggregate S is formed at the position of the withdrawal mark 3a 'of the blow nozzle 3a of the aggregate S. Open through the drill 6.

Step (h) Air is blown from the air nozzle 7 to the lower part of the frame 1 and the bottom surface of the assembly S for cleaning.

Step (i) The model plate 2 is brought into contact with the lower portion of the frame body 1, the blowing frame 3 is placed on the frame body 1, and resin sand is introduced through the holes 5 as in the step (a). Inject into the gap F.

Step (j) A new mold A (upper mold) is obtained by removing the model plate 2 and the blowing frame 3 from the frame body 1. The aggregate S at this time is composed of the original aggregate that remains and the aggregate that is newly formed in the gap F, and the cavity C is formed in the new aggregate.

As described above, according to the method of this embodiment, a part of the aggregate S of the foundry sand of the mold A used is moved in a so-called in-situ manner, and a cavity C is newly formed in the gap F formed by the movement. Since it is formed, the desired cavity C can be obtained by injecting a small amount of resin sand, so that the mold A can be produced at low cost. Further, since the amount of resin sand filled is small, the time for making the mold A can be shortened, and since the amount of sand used is small, it is possible to use high-precision sand, which is expensive, for high-precision casting products. W can be obtained. Further, since the casting can be easily made without using a back metal, it can be applied to a casting product of high-mix low-volume production type.

Although the cold box method is used in the above-mentioned embodiments, a thermosetting mold may be used, or a mold using the raw sand itself may be used. Further, although the filling of the molding sand into the gap F is performed by blow injection, the molding sand may be filled by suction while keeping the gap F in vacuum.

[0021]

According to the method of the present invention, the aggregate of foundry sand in the upper and lower open type frame body from which the cast product is taken out is moved toward one opening of the frame body and is moved from the frame body. The protruding molding sand is eliminated, a model plate having a predetermined cavity outer shape is brought into contact with the other opening of the frame, and the molding sand is filled in the gap between the model plate and the aggregate, and then the model. Since I removed the plate and made an aggregate of foundry sand with a predetermined cavity in the frame,
Since the amount of molding sand used is small and it is possible to manufacture the mold at low cost, since the molding sand used is small,
The time for making the mold can also be shortened.

[Brief description of drawings]

FIG. 1 is a process chart showing an embodiment method of the present invention.

[Explanation of symbols]

 1 Frame 2 Model plate 3 Blow frame 4 Cutter A Mold (upper mold) B Lower mold C Cavity F Gap W Cast product

Claims (1)

What is claimed is: 1. A casting sand in which a casting product is taken out, and an aggregate of casting sand in an upper and lower open type frame body is moved toward one opening of the frame body, and the casting sand is moved and projected from the frame body. , A model plate having an outer shape of a predetermined cavity is brought into contact with the other opening of the frame body, the molding sand is filled in the gap between the model plate and the aggregate, and then the model plate is removed. A method for producing a mold, comprising forming an aggregate of foundry sand having a predetermined cavity in the frame.