JPH0515393Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) The present invention relates to a residue removal device in a vanishing model casting method.

(Conventional technology) In the vanishing model mold casting method, a product model is molded from a synthetic resin that disappears and vaporizes when heated, such as expanded polystyrene.
This is embedded in foundry sand to form a mold, and the heat of pouring the molten metal causes the model to shrink, melt, and vaporize, resulting in a product that imitates the model.

(Problems to be solved by the invention) In the vanishing model mold casting method described above, when pouring molten metal into the product model through guide parts such as sprues and runners made of synthetic resin, the molten metal guide Residues from the molten metal and impurities in the molten metal flow into the product model along with the molten metal, causing rough skin and casting defects.

The present invention was developed to solve the above problems, and its purpose is to prevent residues from the molten metal guide and impurities in the molten metal from flowing into the product model during pouring. The object of the present invention is to obtain a cast product by a vanishing model mold casting method with few surface roughness and casting defects.

(Means for solving the problem) A means for solving the above problem is to form the hot water passage and product model with a synthetic resin that disappears and vaporizes with heat, and embeds it in molding sand to form the mold. In the vanishing model mold casting method, the molten metal path and product model are vaporized and cast into a product by forming a molten metal and pouring molten metal. The dissipation model, which burns at a slower rate than the product model, is interposed in the middle upper part of the alley so that a part of it penetrates into the alley.

(Effect of the above means) According to the above means, by arranging a part of the extinguishing model with a slow combustion rate to face the upper part of the intermediate part in the side passage of the hot water passage, combustion in this part proceeds slower than the surrounding area and disappears. Slag and entrained gas in the upper layer of the molten metal that progresses through the same section are efficiently accumulated in this vanishing section from the initial flow of pouring to the final flow.

(Embodiment) Next, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a vertical cross-sectional view of the first embodiment of the present invention.
The mold is composed of a flask 2, molding sand 3, and a model 4.

The model 4 consists of a sprue 4a, a runner 4b, a runner 4d such as a communicating part 4c, and a product part 4e, and each part is integrally formed of a synthetic resin foam that melts and vaporizes with heat, such as expanded polystyrene. The sprue 4a of the hot water passage 4d is formed vertically, and the runner 4b is formed horizontally, and this part is formed in an L-shape. A small, for example, transverse rectangular model 5 is fitted and engaged so that the lower part of the model 5 penetrates into the runner 4b, and here, a small foaming ratio refers to a model 5 that has a high density and is slightly harder than other parts. Therefore, the combustion rate is slow and the progress of pouring is slow. And the model 5
The cross-sectional area of the runner 4b' on the downstream side of the runner 4b' is made smaller on the upstream side, and the model 5 faces the downstream part 4b' of the runner with its lower part intruding.

The above model 4 is set in the flask 2, and the space between the flask 2 and the model 4 is filled with molding sand to obtain the mold 1 as shown in the figure.

In the above process, the molten metal is poured from the sprue 4a, flows through the sprue 4a, runner 4b, and communication portion 4c while melting and vaporizing, and flows into the product portion 4e, where it is vaporized to obtain a cast product. By the way, the molten metal melts and vaporizes the sprue 4a and runner 4b during pouring, but there is a part of the runner 4b where the vaporization is delayed, and the change in the rate of vaporization and the cross section of the runner 4b from this part. Since the change in molten metal is small, slag and entrained gas in the upper layer of the molten metal traveling through the runner are dammed up and accumulated in this area, and are prevented from entering the product section.

Also, at this time, the vaporization and disappearance of the model 5 part is slower than the vaporization and disappearance of the runners 4b and 4b' around the model 5, and the molten metal from immediately after pouring to the latter half of pouring passes through this part. In the meantime, the model 5 sequentially increases the vanishing area.

Therefore, slag, gas entrainment, etc. in the upper layer of the molten metal are efficiently accumulated in the vanishing section from the initial stage to the final stage of pouring, and are surely prevented from entering the product section.

(Effects of the invention) As is clear from the above, according to the invention, a part of the disappearing model with a slow burning rate, such as one with a small foaming ratio, can be made to face the middle upper part of the side passage of the hot water passage of the model. As a result, slag, impurities, and gas generated in the upper layer of the molten metal are efficiently accumulated and the residues are removed, and their flow into the product is suppressed, preventing casting defects such as rough skin and impurity contamination. This can be prevented as much as possible.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of a mold. In addition, in the drawing, 1 is a mold, 3 is foundry sand, 4 is a model,
4b is a side passage of hot water passage, and 5 is a dissipation model with a slow combustion rate.

Claims (1)

[Scope of utility model registration request] The hot water path and product model are made of a synthetic resin that disappears and vaporizes with heat, and this is embedded in foundry sand to form a mold, and by pouring molten metal, the hot water path and product model are vaporized. In a residue removal device for a vanishing model mold casting method for casting a product, the runner is approximately L-shaped, and a vanishing model having a slower burning rate than the product model is placed in the upper middle of a side passage of the runner. 1. A residue removal device for a vanishing model casting method, characterized in that a part of the residue removal device is inserted into the vanishing model mold casting method.