JPH0818306B2 - Molding method for casting mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is a molding method of a molding die suitable for molding a sintering prototype having a complicated shape by casting a slurry made of powdery granular material slurry. Regarding

(Prior Art) Conventionally, for example, one of the methods used for molding a sintering original body having a complicated shape from ceramic powder is a mud casting method, and a gypsum mold is widely used.

However, in the plaster molds that have been widely used in the past, it was difficult to release a complex-shaped product, and there were problems such as lack of durability. For this reason, the applicant of the present invention has disclosed that
As disclosed in Japanese Patent Laid-Open Publication No. 2004-242242, a method of casting mud in a special casting mold and molding a sintering prototype by using this is developed.

(Problems of the prior art) The casting mold disclosed in Japanese Patent Laid-Open No. 62-268603 is such that a shielding member is closely adhered to a molding surface of an original member, and a molding frame is placed on the shielding member to form a molding frame. Fill the inside with granular material such as silica sand,
The upper surface of the molding frame is hermetically closed to make the inside of the molding frame negative pressure, and thus the shielding member is adsorbed to the side of the particulate matter to make the particulate matter into a vacuum pack shape, and the original member is released from the shielding member to perform molding. I am trying to do it.

In the molding of this mold, the shielding member is heated and brought into close contact with the original member in a state of being improved in flexibility and extensibility. Further, instead of heating, humidifying the shielding member to improve flexibility and extensibility has also been developed since then.
However, there is a limit to the flexibility and extensibility of the shielding member,
There remains a problem that the shielding member cannot be sufficiently adhered to the original member having a rough and complicated shape and is damaged.

(Object of the Invention) The present invention has been made with the object of solving the above problems, and is a casting mold suitable for molding a sintering prototype having a complicated shape with rough unevenness. It is intended to provide a molding method of.

(Means for Solving Problems) According to the present invention, a shielding member that can be dissolved in a slurry solvent or a shielding member that can penetrate a slurry solvent is adhered to the molding surface of an outer shape molding original member, and The molding frame body is placed on the inside of the molding frame body, the particulate matter is filled in the molding frame body, the upper surface of the particulate matter is sealed, and the molding frame body is made a negative pressure to adsorb the shielding member to the particulate matter side. Then, the outer shape molding original member is released from the shielding member to mold a mold having a molding surface for outer shape molding, and a partial mold preliminarily molded with plaster is placed in the molding surface for outer shape molding. It is a molding method for casting molds, which is characterized by fixing to form a mold with a complicated shape that is highly uneven.

(Examples) The structures of members necessary for carrying out the present invention will be described below. In FIG. 1, (1) is a partial mold obtained by adding 55 to 60 parts by weight of water to 100 parts by weight of calcined gypsum and pouring the mixture into a silicon mold and allowing it to stand for a predetermined time. A fixing projection (2) is integrally formed on the.

In FIG. 2, (3) is a rectangular molding frame body having upper and lower surfaces communicating with each other, and a ventilation passage (4) is formed on the peripheral side of the molding frame body (3). The ventilation passage (4) communicates with the inside of the molding frame (3) through a large number of through holes (5) and also communicates with a suction device (not shown) through the ventilation hole (6) and the hose (7). It is connected. Further, in the figure, (8) is an outer shape forming original member (hereinafter referred to as an original forming member).
A molding surface (9) is formed on the upper surface of the original member (8), and the slurry flow passage projections (10) and the fixing projections of the partial mold (1) are formed on the molding surface (9). A plurality of protrusions (11) for forming a hole into which (2) is fitted are formed. Furthermore, a hollow chamber (12) is formed in the original member (8), and the hollow chamber (12) is formed in the molding surface (9).
A plurality of vent holes (13) communicating with each other are bored, and a communication hole (14) communicating with the outside is provided at one end of the hollow chamber (12). The communication hole (14) is connected to a suction device (not shown) through a hose (15).

Explaining the process of making a casting mold for mud casting using the members thus configured, first, as shown in FIG. 2, a water-soluble mold is formed on the forming surface (9) of the original member (8). A film-shaped shielding member (17) made of polyvinyl alcohol and having a thickness of about 30 μm is heated or moistened to impart flexibility and extensibility, and then attached. Then, the suction device of the original member (8) is operated to form the molding surface (9) of the original member (8) from the communication hole (14) through the hollow chamber (12) and each vent hole (13).
While sucking the air on the side, the shielding member (17) attached to the molding surface (9) is suction-adhered along the molding surface (9) of the original shape member (8), and the shielding member (17) is changed to the original shape member (8). The molding surface (9), the slurry flow passage projections (10) and the projections (11) are molded into the same shape.

Then, the surface of the shielding member (17) is mainly composed of a diatomaceous earth, which is a porous aggregate and has a particle size of several microns, and a coating agent made of graphite and ethyl alcohol as a solvent is applied to the surface to form a porous coating. The mold layer (18) is molded. Next, the original member (8)
The molding frame body (3) is placed and fixed on the molding surface (9) side having the shielding member (17), and a particulate matter (19) such as silica sand is filled into the molding frame body (3) from above. The molding frame (3) and the original shape member (8) are integrally vibrated by a vibrator (not shown), and the particulate matter (19) is firmly filled.

Then, the upper surface of the molding frame body (3) is covered with a lid body (21) made of a non-breathable synthetic resin film and the molding frame body (3).
When the suction device on the side is operated, suction is performed through the through hole (5) provided in the inner peripheral surface of the molding frame (3) to make the inside of the molding frame (3) a negative pressure and the shielding member (17) and the lid. The body (21) is sucked to the side of the particulate matter (19) so that the particles of the particulate matter (19) cannot relatively move. As a result, the particulate matter (19), the mold coating layer (18), and the shielding member (17) form the same shape as the molding surface (9) of the original shape member (8), that is, a molding surface (22) for external molding. . (FIG. 2) Then, in the state where the suction operation on the molding frame (3) side is continued, the original member (8)
Side suction operation is stopped and the original shape is maintained in a state where the molding surface (9) side of the original shape member (8) is communicated with the atmosphere from the communication hole (14) through the hollow chamber (12) and each vent hole (13). When the member (8) is removed from the molding frame (3), the molding surface (22) is released from the molding surface (9) of the original member (8) while being held on the molding frame (3) side. It

Next, the mold having the molding surface (22) for outer shape molding is inverted 180 degrees together with the molding frame body (3) to form the molding surface (2) for outer shape molding.
A large number of the partial molds (1) are arranged in 2). (See FIG. 3) At this time, there are a large number of recesses (23) formed by the projections (11) on the molding surface (22) for external shape molding.
The fixing protrusion (2) of the partial mold (1) is fitted into 3) and fixed. (See FIG. 4) As a result, a casting lower mold having a deep groove portion (24) formed radially is produced.

Next, in the same manner as described above, a molding frame body (3 ') having a molding upper mold for molding without a partial mold (1) is mounted on a molding frame body (3) having the molding lower mold for casting. A cavity (25) having a shape identical to that of the ceramic original body (S) which is a body to be molded and has one end opened to the cavity (25) and the other end of the molding frame body (3) (3 '). A slurry channel (26) that opens to the outer wall is formed. (Fig. 4) After that, the base end is a storage tank (28) of ceramics slurry (27).
Insert the tip of an injection cylinder (29), which is connected to the bottom opening, into the slurry flow path (26), and
7) is injected into the cavity (25). Most of the water content of the ceramic slurry (27) is absorbed by the partial mold (1) made of gypsum and comes into contact with the shielding member (17), and the remaining part of the water comes into direct contact with the shielding member (17). Dissolves the shielding member (17) and absorbs it in the mold coat layer (18) and the particulate matter (19) (When a moisture permeable material is used as the shielding member, the shielding member is not dissolved and only moisture is absorbed. Then, a ceramic prototype (S) made of a slurry aggregate is formed in the cavity (25), and thereafter, the same as the prototype disclosed in JP-A-62-268603. It is molded and taken out. Partial type (1)
Can be taken out individually after releasing the suction and collapsing the mold, so that the mold can be easily removed even if the draft is reversed.

(Effect of the Invention) According to the present invention, it is possible to extremely easily mold a casting mold having a complicated shape in which the shielding member made of a resin film is difficult to mold, and the moisture which is the original function of the casting mold is used. The partial molds can be individually extracted from the original body regardless of the draft, without diminishing the absorbing action, and thus can be reused with almost no damage.

[Brief description of drawings]

1 is a perspective view of a partial mold, FIG. 2 is a sectional view showing a molding process of a casting lower mold, and FIG. 3 is a casting lower mold. Top view of the fourth
FIG. 5 is a sectional view showing a state in which a ceramics slurry is being poured into a casting upper and lower molds, and FIG. 5 is a plan view of a sintering prototype.

Claims (1)

[Claims] 1. A shield member which can be dissolved in a slurry solvent or a shield member which can penetrate a slurry solvent is brought into close contact with the molding surface of an original member for external forming, and the molding frame is placed on the close shield member. At the same time, the molding frame is filled with particulate matter, the upper surface of the particulate matter is sealed, the pressure inside the molding frame is made negative, and the shielding member is adsorbed to the particulate matter side, and then the outer shape molding is performed. The original member is released from the shielding member to form a mold having a molding surface for external molding, and a partial mold preliminarily molded with gypsum is placed and fixed in the molding surface for external molding, resulting in a highly complex structure. A molding method for a casting mold, which is characterized in that the mold is shaped.