JPH08300100A - Mold - Google Patents

Abstract

PURPOSE: To provide a mold which prevents the molding sand from entering an exhaust pipe and rapidly discharges the combustion gas through the exhaust pipe hen the exhaust pipe to discharge the combustion gas of a lost wax pattern is embedded in a molding flask. CONSTITUTION: The dry sand 2 is filled in a molding flask 1, and a lost wax pattern 3 and four exhaust pipes 4 are embedded in the dry sand 2. A first wire net 11 having 100 mesh is arranged in the exhaust pipe 4 where a plurality of holes 9 are formed so as to be brought into contact with the inner wall surface of the exhaust pipe 4, a second wire net 12 having 20 mesh is arranged so as to be brought into contact with the inner surface of the first wire net 11, and the shape of the first wire mesh 11 is kept by the second wire net 12 of larger rigidity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved mold for use in the disappearance model casting method.

[0002]

2. Description of the Related Art An example of a mold frame used in a vanishing model casting method is described in Japanese Utility Model Publication No. 3-14039. The mold frame is a mold frame for vanishing model casting in which a vanishing model is buried in foundry sand, and at the bottom of the mold frame, a suction portion is formed in which a plurality of small holes communicating with the inside of the mold frame are formed. ,
Further, a plurality of pipes are attached in a ring shape along the side wall surface of the mold frame and in communication with the suction portion, and the plurality of pipes are provided on the peripheral surface above the height of the vanishing model. The holes are formed, and the small holes formed in the suction portion and the small holes formed in the plurality of pipes are covered with a metal net for preventing suction of foundry sand.

[0003]

However, the wire mesh covering both of the small holes has a small rigidity because the mesh is formed smaller than the dry sand grains by using fine wires. The small holes are covered with one sheet of wire mesh, and when the dry sand put in the mold frame collides with the wire mesh or when the dry sand filled in the mold frame presses the wire mesh, the wire mesh is deformed. , Dry sand enters the pipe from the deformed part of the wire mesh and remains in the suction part. Therefore, there is a problem that the combustion gas generated when the disappearance model replaces the molten metal is difficult to flow into and flow into the exhaust pipe. Therefore, the present invention has been made in order to solve such a problem, the wire mesh covering the small holes is not deformed at the time of charging and filling the dry sand into the mold frame, and into the exhaust pipe of the combustion gas. It is an object of the present invention to provide a mold that allows smooth inflow and distribution of the above.

[0004]

In order to solve the above problems, the mold of the invention according to claim 1 is provided with a plurality of molds in the dry sand filled in the flask which communicates with the outside and has a plurality of side walls. In a mold for vanishing model casting, in which an exhaust pipe having holes is buried, and the plurality of holes are covered with wire mesh, the wire mesh has a first wire mesh having a mesh smaller than the particle size of the dry sand, and the first wire mesh. It is characterized in that it is formed from a second wire mesh having a larger rigidity and a mesh larger than that of the first wire mesh, and in contact with the first wire mesh and holding the shape of the first wire mesh. In the mold of the invention according to claim 2, the mesh size of the first wire mesh is 50
The mesh size of the second wire mesh is 10 to 30 mesh.

The diameter of the plurality of holes formed in the exhaust pipe is preferably 1 to 10 mm. This is because if it is less than 1 mm, the gas generated by burning the vanishing model will have a large ventilation resistance when passing through the holes, and if it is more than 10 mm, the rigidity of the exhaust pipe will decrease significantly. The mold according to claim 2, wherein the mesh size of the first wire mesh is 50 to 20.
0 mesh means that if it is coarser than 50 mesh, the dry sand filled in the casting frame will enter the inside of the exhaust pipe through the mesh and obstruct the flow of the gas in the exhaust pipe, and if it is finer than 200 mesh. This is because the resistance when the gas passes through the first wire net increases and the gas is not satisfactorily exhausted. The mesh size of the second wire net is set to 10 to 30 mesh because the first wire net is more likely to be deformed when it is coarser than 10 mesh, and the gas is the first wire net and the second wire net when it is finer than 30 mesh. This is because the resistance when passing through is increased. The first wire net and the second wire net may be arranged along the inner surface of the exhaust pipe, or may be arranged along the outer surface of the exhaust pipe. Here, when the first wire net and the second wire net are arranged along the inner surface of the exhaust pipe, the first wire net contacts the inner surface of the exhaust pipe, and the second wire net contacts the inner surface of the first metal net. Are arranged as follows. On the other hand, when the first wire mesh and the second wire mesh are arranged along the outer surface of the exhaust pipe, the second wire mesh contacts the outer surface of the exhaust pipe, and the first wire mesh contacts the outer surface of the second wire mesh. Is installed in.

[0006]

After the exhaust pipe in which the holes formed in the side wall are covered with the first and second wire nets is arranged in the casting frame, and the dry sand is put into the casting frame, the dry sand collides with the first wire net. Then, in the state where the dry sand is filled in the flask, the static pressure of the dry sand is applied to the first wire net. At this time, since the second wire net keeps the shape of the first wire net, the dry sand does not enter the exhaust pipe, and when pouring, the burnt gas of the vanishing model is
It flows into the exhaust pipe through the mesh of the two wire mesh and is discharged to the outside.

[0007]

Embodiments of the present invention will be described below with reference to FIGS. As shown in FIG. 1, dry sand 2 (particle size 40 to 40
55 mesh), and the vanishing model 3 made of foamed resin and four exhaust pipes 4 are embedded in the dry sand 2.

The exhaust pipe 4 has an L-shaped exhaust main pipe 5 having a rectangular cross section, and an L-shaped exhaust main pipe 5 which is detachably attached to one end of the exhaust main pipe 5 to communicate the outside with the inside of the exhaust main pipe 5. Communication pipe 6
It is formed by. The exhaust main pipe 5 and the communication pipe 6 are connected via a socket 7, and a cap 8 that prevents the dry sand 2 from entering the exhaust main pipe 5 can be attached to and detached from the tip of the exhaust main pipe 5. It has been inserted.

On the side wall of the exhaust main pipe 5, holes 9 having a hole diameter of 6 mm are formed in a line in the longitudinal direction. The exhaust main pipe 5 is formed by two orthogonal straight pipe portions 5a and 5b. Inside the straight pipe portions 5a and 5b, the inner wall surface 1 of the straight pipe portions 5a and 5b is formed.
A first wire net 11 that contacts 0a and 10b and a second wire net 12 that contacts the entire inner peripheral surface of the first wire net 11 are arranged. The mesh size of the first wire net 11 is 100 mesh, the mesh size of the second wire net 12 is 20 mesh (see FIG. 3), and the shape of the first wire net 11 is retained by the second wire net 12 having high rigidity. There is. The first wire net 11 and the second wire net 12 are inserted into the exhaust main pipe 5 by inserting the straight pipe portion 5a.
And the straight pipe part 5b were separately performed. Straight pipe part 5
The shape of the inner wall surface 10a of a or the inner wall surface 1 of the straight pipe portion 5b
The shape of the second wire nets 12 to be inserted is adjusted so as to follow the shape of 0b, the first wire nets 11 are wound around the respective second wire nets 12 to be integrated, and inserted into the pipe from both ends of the exhaust main pipe 5. .

As shown in FIG. 2, in the four exhaust pipes 4, the straight pipe portion 5a of the exhaust main pipe 5 is along the bottom surface 13 and the side wall surface 14 of the casting frame 1, and the straight pipe portion 5b is formed by casting. It is arranged along the side wall surfaces 14 of the frame 1 that are adjacent to each other, and the tip end opening 15 of the connecting pipe 6 is open toward the outside of the casting frame 1.

Next, an extinction model casting method using the mold will be described. When the dry sand 2 is put into the casting flask 1, the dry sand 2 collides with the first wire net 11 provided in the exhaust pipe 4, and the first wire net 1
A force to deform 1 is added. Then, dry sand 2 is added to the flask 1.
In the state of being filled inside, the static pressure by the dry sand 2 is applied to the first wire net 11. At that time, since the first wire net 11 is supported by the second wire net 12 having high rigidity to maintain its shape, the first wire net 11 is not deformed and the dry sand 2 is prevented from entering the exhaust pipe 4. To be done. After the mold 1 is filled with the dry sand 2, the molten metal is poured into the lost model 3 to replace the lost model 3 with the molten metal, and the combustion gas of the lost model 3 moves in the dry sand 2 and is cast. While being discharged from the upper opening of the frame 1,
It is discharged from the exhaust pipe 4 to the outside through the two wire nets 11 and 12.

[0012]

EFFECTS OF THE INVENTION According to the present invention, since dry sand does not enter the exhaust pipe, and the combustion gas of the vanishing model quickly flows in the exhaust pipe, the combustion gas scatters well from the mold. That is, it is possible to easily obtain a casting free from gas defects, which largely contributes to improvement in productivity.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a mold according to the present invention.

FIG. 2 is a plan view of the mold.

FIG. 3 is a diagram showing how meshes are overlapped when a first wire net and a second wire net which compose the mold overlap each other.

[Explanation of symbols]

 1 Casting Frame 2 Dry Sand 4 Exhaust Pipe 9 Hole 11 First Wire Mesh 12 Second Wire Mesh

Claims (2)

[Claims] 1. A mold for vanishing model casting, wherein an exhaust pipe communicating with the outside and having a plurality of holes in a side wall is embedded in dry sand filled in a casting mold, and the plurality of holes are covered with a wire mesh. In, the wire mesh has a mesh smaller than the particle size of the dry sand.
A wire mesh and a second wire mesh having a mesh larger than that of the first wire mesh and larger than the mesh of the first wire mesh, and contacting the first wire mesh and maintaining the shape of the first wire mesh. Characteristic mold. 2. The mesh size of the first wire mesh is 50 to 2
The size of the mesh of the second wire mesh is 1
The mold according to claim 1, which is 0 to 30 mesh.