JP5319945B2 - Model having disappearance model in part and casting method using the same - Google Patents

Description

  The present invention relates to the manufacture of a cast product using a green mold, and relates to a model in which a disappearance model is partially attached to an existing model made of a mold or a wooden mold to be used, and a casting method using the model.

Casting using a green mold is utilized in many industrial products having complicated shapes such as automobile parts and electric parts, and a general manufacturing method is performed by the following procedure.
First, a model composed of an upper mold and a lower mold is placed in a mold, and cast sand is filled and shaped. Next, the model is removed and mold matching is performed to match the upper and lower molds. This completes the preparation of the mold and casts the desired molten metal into the mold frame, waits for solidification, opens the frame and removes the sand, and finishes the casting process with weir breakage and finishing.
In order to create a more complicated shape in this process, the model is divided into a plurality of members and combined, not a single object.
There exists a thing of patent document 1 as a molding method which uses a vanishing model for a self-hardening mold.

JP 2007-90384 A

Casting has an advantage in that it can have a complicated shape. For this reason, it is an absolute requirement that the model can be finally disassembled after being divided into two parts. Therefore, the model has been disassembled in many ways and is complicated and strange. Therefore, it takes a lot of time for the production as well as the production cost, and it is a factor that deteriorates the workability even in die cutting at the time of modeling.
It is an object of the present invention to improve the workability of the casting process while making a simple structure model by improving the model used for the green mold.

A model used for a green mold, when an existing model manufactured with a mold or a wooden mold and a disappearing model made of a material that disappears due to the heat of molten metal are attached to the existing model, and when molding is filled with molding sand The vanishing model is separated from the existing model and stored in the foundry sand, the existing model has a fixing portion for attaching the vanishing model, and the fixing portion has a suction port for sucking the vanishing model to attach the vanishing model. It is a model having a disappearance model in part characterized by being.

A casting method using a green mold, wherein a projection part that requires a split mold, such as a projection part of a model, is composed of a material that disappears due to the heat of the molten metal at the time of casting, and the projection part is separated from the model at the time of modeling and foundry sand A casting method using a green mold remaining in the mold and casting a desired molten metal, wherein the disappearance model of the protrusion is fixed to an existing model by negative pressure, and a disappearance model is partially attached This is a casting method using a green mold.

Since the disappearance model made of the material that disappears due to the heat of the molten metal is the part that is stored in the casting sand when pouring, the existing model does not need to be a model that completely matches the product, and a model with a simple structure can be used. It is not necessary to take measures such as dividing.
Moreover, what was used with respect to the conventional green sand can be applied as it is for the casting method.
Furthermore, all processes other than the disappearance model attaching process can be produced in the same process as the conventional process.

  Since the existing model has a fixing part for attaching the disappearance model, the disappearance model can be securely attached to a desired location of the existing model and can be a model that is not different from the product.

  Since the protrusions provided in the fixed part are formed in parallel with the model drawing direction during modeling, the model can be smoothly modeled without causing damage to the foundry sand when the disappearing model is separated from the existing model.

  Since the fixed part is equipped with a suction port that sucks the disappearance model to attach the disappearance model, the disappearance model can be adjusted in the suction force to make various shapes, sizes, materials, mounting locations, etc. Can correspond to a model.

Protrusions that require a split surface, such as model protrusions, are made of a material that disappears due to the heat of the molten metal during casting, and the protrusions are separated from the model during modeling and remain in the foundry sand. Therefore, it is possible to cast a product having a shape that is difficult to manufacture by ordinary green casting.
In addition, the number of split surfaces and mating surfaces of the model is reduced, and burrs of the product are significantly reduced.

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of the product 1. FIG. 2 is a cross-sectional view of the upper mold that divides the product into two and has a runner. 3 is a cross-sectional view of a lower mold corresponding to the upper mold of FIG.
In FIG. 1, an upper part 1A and a lower part 1B of a product 1 which is an upper mold are divided at a ZZ portion shown in the figure by dividing surfaces 2A and 2B. It is desirable that ordinary castings have a shape that allows die removal. The shapes that do not allow die removal are: (1) sand with a draft angle of less than 1 degree, or with a reverse slope, (2) It protrudes in a direction perpendicular to the direction. Therefore, in this embodiment, the shape parts that can be removed from the mold are called the upper mold 3A and the lower mold 3B of the existing model, respectively, and the shape parts that cannot be removed from the mold are the upper mold 4A and the disappearance model, respectively. Let it be type 4B. At this time, the vanishing models 4A and 4B that cannot be removed from the mold are made of a material that disappears, for example, foamed polystyrene.

In FIG. 2, the split surface 7A of the existing model 3A corresponding to the split surface 2A of the product 1 is joined to the model surface plate 6A, and the disappearance model 4A, which is a part that cannot be removed from the mold, is attached to the existing model 3A. Furthermore, the existing model 3A is provided with a runner 5 for introducing a molten metal as a product.
The vanishing model 4A needs to be attached so as not to drop off from the existing model 3A at the time of modeling, but at the time of mold matching, it must be left in the raw sand, and the fixing part 8A for attaching the vanishing model 4A to the existing model 3A Is provided.
The fixing portion 8A of the existing model 3A includes a protrusion 9 that is pierced from the existing model 3A. A plurality of projections 9 are formed in a tapered shape so as to position the vanishing wedge mold 4A. Importantly, the protrusions 9 are firmly fixed so that they do not fall off during molding, and the vanishing wedge mold 4A is pre-existing during mold matching. It is necessary to separate from the model 3A. Therefore, it is desirable that the protrusions 9 be attached in parallel to the direction in which the rough model 3A at the time of mold matching, which will be described later, is extracted from the raw sand 14.
When the material of the disappearing model 4A is made of foamed polystyrene, it can be fixed by being pierced into the protrusion 9 and can be easily attached to the existing model 3A.

  FIG. 3 is a model of the lower part 1B of the product 1. Like the upper part 1A, the split surface 7B of the existing model 3B is joined to the model surface plate 6B, and the existing model 3B is a part that cannot be removed from the mold. Install 4B. At this time, the surface to which the disappearance model 4B is attached is formed substantially parallel to the direction in which the existing model 3B is extracted at the time of mold matching, and thus the projection 9 described above cannot be attached. Accordingly, the disappearing model 4B is provided with a fixing portion 8B having a suction port 10 so as not to drop off from the existing model 3B during modeling. The fixed portion 8B has a structure in which the vanishing model 4B is pressed against the existing model 3B by negative pressure, and the suction port 10 is a vacuum (not shown) from the fixed portion 8B through the suction path 11 provided in the existing model 3B and the model surface plate 6B. Connected to the pump. Of course, the fixed portion 8B is provided with a guide portion for positioning when the vanishing model 4B is attached.

Next, the procedure of the manufacturing process will be described based on FIG.
1. Preparation of the general wedge type Fig. 1a shows the lower stage 3B of the general model, and Fig. 1b shows the preparation state of the general model 3A. The model split surfaces 7A and 7B are attached and fixed to the model surface plates 6A and 6B, respectively.
2. Attachment of disappearance model (made of foamed polystyrene) to the general model FIG. 2a shows a lower mold and 2b shows an upper mold.
As described in detail with reference to FIGS. 2 and 3, the disappearance models 4A and 4B made of foamed polystyrene are attached. At this time, the disappearance model 4B is fixed by the negative pressure by the vacuum pump 12.
3. FIG. 3a shows a lower mold and 3b shows an upper mold.
When the attachment of the model is completed, the mold 13 is attached to the model surface plate 6A-6B, and fresh sand 14 is filled from above. At this time, careful work is required so that the disappearing models 4A and 4B attached to the general models 3A and 3B do not fall off. The filled fresh sand 14 is molded so that pressure is applied from above in the drawing so that the entire mold of fresh sand 14 has strength.
4). When the mold shaping is completed, the general models 3A and 3B are extracted from the raw sand 14 together with the model surface plates 6A and 6B. At this time, it is important to extract only the general models 3A and 3B and leave the disappeared models 4A to 4B in the raw sand 14, which requires careful work.
The mating surface of the lower mold 17 formed in the mold 13 is set on the casting surface plate 15 so as to face upward, and the upper mold 16 is assembled thereon. At this time, the portion formed in the approximate models 3A and 3B becomes the cavity portion 18, and the vanishing models 4A and 4B exist in connection with the cavity portion 18. A pouring gate 19 is provided at the upper end of the cavity for pouring molten metal.
5. When the casting mold matching is completed, the molten metal 20 in which the material of the product 1 is melted is poured from the gate 19.
The poured molten metal 20 fills the cavity 18, melts the disappearance models 4A and 4B by heat, and also fills the disappearance models 4A and 4B. As a result, a shape corresponding to the product 1 can be secured.
At this time, when the disappearance models 4A and 4B are melted by heat, gas is generated, but fortunately the raw sand 14 has air permeability and is released outside the mold 13 and remains inside. Absent. However, a suction port by negative pressure may be provided in the mold according to the shape of the product and the size of the disappearance model.
6). When the open frame / sand-dropped molten metal 20 is solidified in the molds 16 and 17, the casting surface plate 15 is removed from the lower part of the mold 13, and the casting 21 is taken out from the mold 13 together with the fresh sand 14. And the raw sand 14 adhering to the surface of the casting 21 is removed by short blasting or the like.
7).櫃 Casting parts such as ballast / finished product 1 and runway 5 are separated to remove unnecessary burrs.

In the above manufacturing process, the difference from the process using the conventional green mold is only that the process of attaching the disappearance model is increased, and everything else is the same as the conventional process. For this reason, there is no need for drastic line changes, and the process is not disturbed, and a simple model can be used.

1 is a cross-sectional view of a product 1. FIG. It is sectional drawing of the upper mold | type which divides a product into two and is equipped with a runner. It is sectional drawing of the lower mold | type corresponding to the upper mold | type of a product. It is sectional drawing which shows the procedure of a manufacturing process.

Explanation of symbols

1 Product 3A Upper model 3B of the existing model Lower model 4A of the existing model Upper model 4B of the disappearing model Lower model 8 of the disappearing model Fixed part 9 Protrusion 10 Suction port

Claims (2)

A model used for a green mold, when an existing model manufactured with a mold or a wooden mold and a disappearing model made of a material that disappears due to the heat of molten metal are attached to the existing model, and when molding is filled with molding sand The vanishing model is separated from the existing model and stored in the foundry sand, the existing model has a fixing portion for attaching the vanishing model, and the fixing portion has a suction port for sucking the vanishing model to attach the vanishing model. A model having a disappearance model in part characterized by being. A casting method using a green mold, wherein a projection part that requires a split mold, such as a projection part of a model, is composed of a material that disappears due to the heat of the molten metal at the time of casting, and the projection part is separated from the model at the time of modeling and foundry sand A casting method using a green mold remaining in the mold and casting a desired molten metal, wherein the disappearance model of the protrusion is fixed to an existing model by negative pressure, and a disappearance model is partially attached A casting method using a green mold.

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