JP2517174B2 - Mold for centrifugal casting - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a centrifugal casting mold for producing a hollow casting by casting molten metal inside while being driven and rotated.

[Conventional technology]

As the mold for centrifugal casting described above, a mold made of heat-resistant steel has been mainly used in the past.After applying a coating material for preventing seizure on the inner peripheral surface of the mold, the mold is driven to rotate. The method of pouring the molten metal inside is adopted.

[Problems to be Solved by the Invention]

However, since the above-mentioned conventional mold is made of steel and has high strength and excellent durability, it can be repeatedly used without having to remake it for each casting. For example, a pipe is cast by this type of centrifugal casting. In such a case, if the number of types of outer diameter is small, it is sufficient to prepare a mold with an inner diameter corresponding to each outer diameter, but in order to make pipes with various outer diameters, an extremely large number of molds must be prepared. However, if a large amount of pipes with different outer diameters are produced, the effect of repeated use, which is a characteristic of the mold, can be fully utilized, but if the production amount of pipes of various diameters is small, each cast The ratio of equipment costs to products was large, and the rise in product costs was unavoidable.

In view of the above situation, an object of the present invention is to provide a mold for centrifugal casting suitable for high-mix low-volume production.

[Means for solving the problem]

The first of the molds for centrifugal casting of the present invention for achieving the above object
The characteristic configuration is that the paperboard impregnated with the mold coating material is formed into a tubular shape.

Further, the second characteristic configuration of the mold for centrifugal casting of the present invention for achieving the above-mentioned object is to insert a mold, which is formed in a tubular shape from paperboard impregnated with a coating material, into a tubular metal frame body. I had it held.

[Action]

That is, as a result of repeated experiments to achieve the above-mentioned object, it was found that a paperboard which is easy to form but also strong and relatively high in rigidity can be used as a mold for centrifugal casting. By adopting a material that is easier to mold than metal, various different types of centrifugal casting molds can be obtained very easily.
In other words, even if you apply a flammable material called paperboard to the mold,
In the case of centrifugal casting, when casting, the molten metal immediately covers the surface of the mold and shuts off the atmosphere from the surface of the mold, so the material does not burn and carbonizes, but its shape retention He found that he did not lose sex.

However, if the paperboard is used as it is, if the molten metal reacts with the surface of the paperboard during casting, in some cases, the molten metal may be burned on the inner peripheral wall of the mold, resulting in deterioration of product quality, Alternatively, since the mold becomes unusable immediately, in the mold for centrifugal casting of the first characteristic configuration of the present invention, the mold made of paperboard is protected in advance by impregnating the mold with a coating material, Forming a protective layer on the inner peripheral surface of the mold to prevent the seizure of the molten metal, avoiding the molten metal reacting with the material of the paperboard, avoiding the above inconvenience, with only that mold The centrifugal casting mold is constructed. Furthermore, it is also possible to form the unevenness on the inner peripheral surface of the paperboard mold and to form the uneven surface on the outer surface of the obtained cast product by utilizing the workability of the paperboard.

Further, if the entire die is formed from the paperboard alone, in order to obtain sufficient strength as the die when casting a large product, the paperboard must be extremely thick, which may be uneconomical. In the mold for centrifugal casting having the second characteristic configuration of the present invention, a high-strength metal tubular frame is externally fitted to the outside of a mold in which a paperboard impregnated with a coating material is tubularly formed. By having a structure in which the mold is fitted and held in the frame, the frame can be provided with necessary strength, and the mold for centrifugal casting as a whole can have sufficient strength for centrifugal casting. . Moreover, the mold is made of paperboard that is easy to mold, and its thickness and shape can be easily changed. A casting die can be obtained very easily, and the paperboard is impregnated with a coating material in the same manner as the centrifugal casting die of the first characteristic constitution, so that seizure of the molten metal can be prevented and at the same time, a casting product obtained. It is also possible to form an uneven surface on the outer surface of the.

〔The invention's effect〕

Therefore, according to the first characteristic configuration, even if there are many variations in the outer diameter and the shape of the cast product, for example, when producing a cast product such as a pipe, there are a plurality of paperboard molds suitable for the variation. This mold for centrifugal casting is easier to manufacture and costs less than those made of metal, so it is possible to reduce the product cost when obtaining cast products of high-mix low-volume production. be able to.

Further, if the mold for centrifugal casting having the second characteristic configuration is used, even if there are many variations in the outer diameter and shape of the cast product, there is only one type or relatively few metal tubular frame bodies. It is sufficient to prepare only the types, and it is sufficient to prepare a plurality of types of cardboard cylindrical molds by changing the thickness and the inner surface shape so as to match the variations. In the case of the first characteristic configuration Similar to the above, the production cost can be reduced by making the various types of tubular molds made of paperboard, which is an easy-to-form material, and the strength of the centrifugal casting mold as a whole is mainly metal tubular. Since it is possible to reduce the mechanical load of the paperboard mold by applying the load to the frame body, it is possible to further simplify the molding of the mold and reduce the materials used, and further reduce the cost.

As a result, according to the present invention, it is possible to provide a mold for centrifugal casting which is cost-effective and can be produced in small quantities for a wide variety of products.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, a pair of drives is provided below the centrifugal casting mold (M) that is composed only of the mold (1) formed of a tubular paperboard with the shaft core (P) oriented horizontally. Centrifugal casting apparatus in which a driving roller (2A) and a pair of idler rollers (2B) are dispersedly arranged in the circumferential direction of the mold (M), and a motor (3) continuously connected to the driving roller (2A) is provided. Is configured.

The mold (M) is according to the first characteristic configuration of the present invention, and as shown in FIG. 1, is formed by molding a paperboard into a tubular shape, and burns the molten metal on the inner peripheral surface thereof. In order to prevent sticking, a mold type material is impregnated in advance. And since it is made of paperboard that is low in material cost and easy to mold, and multiple types of molds (M) with different inner diameters can be easily obtained, many types of diameters can be maintained while keeping the mold equipment cost low. It is possible to obtain a cast product, and it is easy to change the inner diameter of the mold (1) and cope with various variations.

The above-described paperboard centrifugal casting mold (M) according to the first characteristic configuration can be independently applied as a slight centrifugal casting mold (M) when a cast product is a relatively small one. However, when casting a larger product, it is used as the mold (1) of the centrifugal casting mold (M) according to the second characteristic configuration of the present invention described below.

FIG. 4 shows the centrifugal casting apparatus that casts using the mold (M) for centrifugal casting having the second characteristic structure, and the mold (M) for centrifugal casting having the above-mentioned first characteristic structure is shown in FIG. Since it is the same as that using, the description will be omitted.

As shown in FIG. 3, the mold (M) for centrifugal casting having the second characteristic structure is formed by forming a paperboard on a frame body (5) made of heat-resistant steel and impregnating the mold material in advance. Since the mold (M) for centrifugal casting having the first characteristic structure is internally fitted and held as the mold (1), the mold (1) is made of paperboard whose material cost is low and molding is easy. It is easy to change the inner diameter of the centrifugal casting mold (M) and adapt to various variations. That is, as the frame body (5), one kind or an extremely small kind of inner diameter is prepared, while the mold (1) fitted in the frame body (5) has different wall thickness. By preparing a plurality of types with different inner diameters, it is possible to obtain castings of many types of diameters while keeping die equipment costs low.

The mold (M) for centrifugal casting according to the second characteristic configuration of the present invention described above is useful when casting a large product as described above, but is applied when casting a small product. Alternatively, the amount of paperboard used can be reduced as compared with the case of using the mold (1) having the first characteristic constitution alone.

Further, also in the centrifugal casting mold (M) according to the first characteristic structure, the centrifugal casting mold (M) using the centrifugal casting mold (M) as the mold (1) ( Also in M), since the paperboard mold (1) is preliminarily impregnated with the mold coating material, it is easy to mold and therefore the strength is not so high, but seizure of the molten metal is prevented. Therefore, it can be used repeatedly to some extent.

When centrifugal casting is performed using the mold (M) for centrifugal casting according to the first characteristic configuration or the mold (M) according to the second characteristic configuration, the mold (M) is rotated while being driven and rotated. 1) Cast the molten metal inside. The casting method itself is not different from the conventional method. Since this casting is carried out in a short time, it hardly affects the inner peripheral surface of the paperboard mold (1), and even if carbonization occurs, the dimensional change hardly occurs. On the other hand, since the molten metal is not rapidly cooled by the metal, there is also an effect that the obtained cast product has a dense and high-quality structure.

[Another embodiment]

 Next, another embodiment of the present invention will be listed.

<1> For the paperboard used as the material of the mold (1), various materials such as cardboard, corrugated paper, and chip balls can be used.

<2> Concavities and convexities may be formed on the inner peripheral surface of the mold (1) by utilizing its good workability, and the concavities and convexities may be formed on the outside of the obtained cast product.

<3> The specific configuration of the mechanism for driving and rotating the mold (M) for centrifugal casting can be appropriately changed.

<4> When impregnating the mold (1) with the mold coating material, in addition to the method of simply immersing the mold (1) in the mold coating material and leaving it for a predetermined time, suction is performed so as to depressurize the internal space of the mold (1). Therefore, a method of increasing the impregnation effect may be adopted.

<5> In order to improve the dimensional accuracy and smoothness of the inner peripheral surface of the mold (1), a surface coating of silicon resin or the like may be applied, or a resin sheet or the like may be spread.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of drawings]

The drawings show an embodiment of a mold for centrifugal casting according to the present invention. Fig. 1 is a partially cutaway perspective view of the mold for centrifugal casting according to the first characteristic constitution of the present invention, and Fig. 2 is the first characteristic constitution. FIG. 3 is a plan sectional view of a centrifugal casting apparatus using the centrifugal casting mold of FIG. 3, FIG. 3 is a partially cutaway perspective view of the centrifugal casting mold of the second characteristic structure of the present invention, and FIG. 4 is the second characteristic structure. FIG. 7 is a plan sectional view of a centrifugal casting apparatus using the centrifugal casting mold of FIG. (1) ... mold, (5) ... frame.

Claims (2)

(57) [Claims] 1. A mold for centrifugal casting, which is formed in a tubular shape from a paperboard impregnated with a mold coating material. 2. A mold for centrifugal casting in which a cylindrical mold (1) made of paperboard impregnated with a mold coating material is fitted and held in a cylindrical metal frame (5).