JPS6355385B2 - - Google Patents

Description

Detailed Description of the Invention "Field of Industrial Application" The present invention involves embedding a fugitive foam resin model in foundry sand, and causing the model to vaporize and disappear with the injected molten metal (hereinafter referred to as molten metal). This relates to a full-mold casting method in which a casting is cast while displacing molten metal.

``Prior art'' There are many conventional full mold casting methods in the literature, and among them, the most representative ones are:
For example, in Japanese Patent Publication No. 49-32167, in order to prevent the mold sand layer from collapsing, it is a method to continuously maintain the mold sand layer in a depressurized state from just before the start of pouring until the completion of pouring. -5004 is mainly suitable for large castings and aims to improve workability.
It is a vacuum mold casting method in which only the sprue is exposed on the top surface of the flask, and the top surface of the flask excluding the sprue is sealed with metal foil or thin metal plate. and, for the purpose of improving workability, a casting method is disclosed in which a synthetic resin liquid is coated on the entire outer periphery of a fugitive original shape having a fugitive sprue body.

"Problems to be Solved by the Invention" These technical documents mentioned above are effective means for solving the respective problems, but it is impossible to simultaneously cast a large number of cast products using these casting methods. It was hot. The main reason for this is that it is impossible to supply molten metal corresponding to the volumes of a large number of fugitive foam resins in an orderly manner, resulting in an oversupply or shortage of molten metal. It is thought that this causes the injected molten metal to move up and down within the mold sand layer of the fugitive foamed resin, causing molten metal wrinkles, rough skin, and even collapse of the mold in extreme cases.

"Means for Solving the Problems" In view of the above, the present invention has the purpose of orderly supplying molten metal corresponding to the volume of a large number of fugitive foamed resins.
A sprue made of fugitive foam resin, a runner connected to this sprue, and each flat plate-shaped weir that branches out from this runner (hereinafter simply referred to as a weir in principle).
A flat plate-shaped convergence part that is converged toward the model (hereinafter simply referred to as the convergence part in principle)
, and this converging part is arranged approximately 15 cm to 20 cm above the bottom surface of the model,
By controlling the molten metal poured from the sprue using the bottom pouring method at this converging section, and by making this converging section a boundary in the horizontal direction, the molten metal poured from this converging section will flow through the boundary. The model is vaporized and dissipated through the lower flow path where the molten metal flows toward the bottom of the model and the upper flow path where the molten metal flows toward the top of the model with the convergence part as a boundary, thereby replacing the model with the molten metal. The object of the present invention is to provide a multi-cavity casting method in the full mold casting method.

"Operation" After burying the model 2, weir 3, runner 4, and sprue 5 in the molding sand 6 of the flask 1, operate the vacuum pump,
When the molten metal is poured from the weir drum 11 while reducing the pressure in the flask 1 through the exhaust pipe 8 and the jacket 7, the sprue 5
→ Runway 4 → Weir 3 and convergence part 3a → Model 2 are burned and vaporized to form a cavity in model 2, and this cavity is replaced with molten metal, resulting in a good quality casting. Ru. In this process, the weir 3 is provided with a convergence part 3a, and since this convergence part 3a is in the shape of a flat plate, the inflow of slag, dregs, etc. is blocked, but the inlet for the molten metal is secured. , smooth pouring is possible, the amount of poured molten metal passing through the weir 3 is regulated, and the molten metal is sequentially and well supplied to the model 2, and as mentioned above, slag, scum, etc. are removed from the model 2. It is possible to prevent the inflow of Furthermore, since the converging part 3a is arranged in a continuous manner approximately 15 cm to 20 cm above the lower surface of the model 2, the molten metal poured through the sprue 5 by the bottom pouring method is controlled by the converging part 3a, Moreover, by making this convergence part 3a a boundary C in the horizontal direction, the molten metal poured from this convergence part 3a flows toward the lower part of the model 2 via the boundary C in the downward flow path A.
First, the lower part of model 2 (same for model 2 below the boundary C) is replaced with molten metal. Thereafter, the upper part of the model 2 (the same applies to the model 2 above the boundary C) is replaced with the molten metal in the upper flow path B where the molten metal flows toward the upper part of the model 2 using the convergence part 3a as the boundary C. The lever model 2 is vaporized and disappeared, and the replacement of the lever model 2 with the molten metal is smoothly achieved.

``Example'' The drawing shows an example of the present invention, in which 1 is a mold having a ventilation structure, 2 is a model made of fugitive foamed resin, and a large number of molds (six in this example) are placed in the mold 1. )
The model 2 is connected to the runner 4 via a weir 3 having a convergent part 3a, and one weir 3 is provided for each model 2, and As shown in the figure, a convergent portion 3a is provided at a portion connected to the model 2. A sprue 5 is erected at one end of the runner 4, and an upward portion is erected at the other end (not shown). The convergence part 3a of the weir 3 is preferably regulated so that approximately 40% of the flow rate of the molten metal in the weir 3 flows. This is because as the model 2 disappears, the molten metal flows in from below in an orderly manner. Similarly, it is best to place the weir 3 at a location approximately 20 cm below the bottom surface of the model 2, and ideally 15 cm below the bottom surface of the model 2.
cm is good. In this way, the molten metal poured by the bottom pouring method through the sprue 5 is controlled by the convergence part 3a, in combination with the fact that the convergence part 3a is configured in the shape of a flat plate, that is, This convergence part 3
By setting a as a boundary C in the horizontal direction, the molten metal poured from the convergence part 3a first passes through the lower part of the model 2 in the downward flow path A that flows toward the bottom of the model 2 via the boundary C. The model 2 is vaporized and disappeared through the process of replacing the upper part of the model 2 with the molten metal, and then replacing the upper part of the model 2 with the molten metal in the upper flow path B where the molten metal flows toward the upper part of the model 2 using the convergence part 3a as the boundary C. , the replacement of the lever model 2 with the molten metal is achieved smoothly. 6 is foundry sand, 7 is a jacket, and a casting flask 1 has a ventilation structure.
It is connected to a vacuum pump (not shown) via an exhaust pipe 8, and the pressure is reduced via this vacuum pump. 9 is a metal foil or thin metal plate that seals the upper surface of the flask 1.

"Effects of the Invention" As described in detail above, the present invention is a method of connecting a runner and a model via a single weir, and providing a convergence section to the weir to regulate the amount of molten metal flowing through the weir. As a result, molten metal can be supplied to multiple models in an orderly manner from a single sprue through a runner, making it possible to simultaneously cast a large number of castings, which was considered difficult with conventional technology, and making work easier. This will help improve productivity and reduce costs. In particular, since the convergence part is provided in the weir, the inflow of slag and debris is prevented, and a cast product with a good casting surface and no cavities can be obtained.

In particular, in the present invention, since the weir and the convergence part connected to the weir are configured in the shape of a flat plate, the inflow of slag, scum, etc. is prevented, but the inlet for the molten metal is secured. , it is possible to pour molten metal smoothly, and the amount of molten metal that is poured and passes through the weir is regulated, so that the molten metal is supplied to the model in a sequential manner, and at the same time, it is possible to prevent slag, scum, etc. from flowing into the model. It is extremely effective. Furthermore, since the convergence part is arranged in a continuous manner approximately 15 cm to 20 cm above the bottom surface of the model, the molten metal poured through the sprue by the bottom pouring method can be controlled by this convergence part. By taking the boundary in the horizontal direction,
The molten metal poured from this convergence section flows downward through the model via the boundary, and through the upper flow path through which the molten metal flows upward through the model using the convergence section as a boundary. The molten metal can be smoothly replaced with the lever model by vaporizing and disappearing the molten metal. In addition, by providing the convergence part in the above-mentioned positional relationship, the effect of rising hot water and rising hot water can be greatly expected, and it also plays the role of discharging air, scum, slag, etc. in the mold during pouring. By doing so, the casting surface becomes clean, and the weight of the molten metal applies pressure to the casting before solidification, thereby eliminating the occurrence of cavities, and greatly contributing to improving the denseness of the material. Furthermore, since the convergent part is configured in the shape of a flat plate, no skill is required when attaching the convergent part to the model using adhesive or adhesive tape, and this work can be done easily and quickly, increasing efficiency. is beneficial;
Or, any number of people can easily perform this type of work.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; Fig. 1 is a vertical cross-sectional side view of the device used in this method, Fig. 2 is a cross-sectional top view of the same, and Fig. 3 is an enlarged front view showing the relationship between the model and the weir. FIG. 4 is an enlarged perspective view showing the relationship between the runner and the weir. 1... Casting flask, 2... Model, 3... Weir, 3a... Convergence part, 4... Runway, 5... Sprue, 7... Jacket, 8...
Exhaust pipe.

Claims (1)

[Claims] 1. In a full mold casting method in which a model of fugitive foam resin is used for casting, fugitive foam resin is placed in a box-shaped flask that has a ventilation structure and is equipped with decompression means on the outer periphery. The sprue, the runner connected to this sprue, and the flat plate-like weirs that branch out from this runner in large numbers form a flat plate-like convergence part that converges toward the model. A flat plate-shaped converging part is arranged in a row approximately 15 cm to 20 cm above the lower surface of the model, and the molten metal poured through the sprue in a bottom pouring manner is controlled by this flat plate-shaped converging part. At the same time, the model is vaporized and disappeared through a lower channel through which the molten metal flows toward the bottom of the model with this convergence section as a boundary, and an upper flow channel through which the molten metal flows toward the top of the model with the convergence section as a boundary.
A multi-cavity casting method in the full mold casting method in which the lever model is replaced with molten metal. 2. A multi-cavity casting method in the full mold casting method according to claim 1, wherein approximately 40% of the molten metal supplied to the flat plate-shaped weir is regulated by the flat plate-shaped convergence part.