JPH0577214A - Casting mold - Google Patents

Abstract

PURPOSE:To provide a casting mold capable of obtaining a perfect molded object having no problem in both of appearance and quality by preventing the generation of shearing-off or cracking. CONSTITUTION:The slip casting passage 3 provided to a casting mold having air permeability is constituted of the straight cylindrical part 5 having no air permeability ranging from the inlet of the passage 3 to the almost central part thereof and an air-permeable inclined cylindrical part 6 whose caliber gradually expands from the straight cylindrical part 5 toward the outlet of the casting passage to smooth the pulling-off of a molded object at the time of demolding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting mold which can prevent the occurrence of biting and cracks and can obtain a complete molded product having no problem in terms of external shape and quality. ..

[0002]

2. Description of the Related Art For example, as a method of molding a ceramic product, a pair of upper and lower molds having air permeability are matched with each other, and a molding raw material is poured into a molding cavity formed inside from a casting passage, After that, a pressure casting method is known in which casting is performed while dehydrating under pressure. In the casting mold used in the above-mentioned molding method, it is widely practiced to coat the casting passage of the sludge with a non-breathable film so that the sludge can be easily injected into the cavity. ing.

However, since the conventional casting passage for sludge is formed as a straight cylindrical shape, one of the molded bodies filled in the casting passage at the time of releasing the molded body after the casting molding is performed. There was a problem that the part did not come out well and the cutout was extended to the inside of the molded product, resulting in a defective product due to an incomplete external shape. Even if the bite is not generated, the difference in the mold release easiness between the casting passage and the cavity causes a crack near the boundary between the two to reduce the strength, etc. There was a problem that it would be a problem.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems and reliably prevents the occurrence of biting, cracking, etc. at the time of mold release of a molded body after cast molding. It was completed for the purpose of providing a casting mold capable of obtaining a complete molded product having no problem in terms of external shape and quality and efficiently manufacturing the molded product at a high yield rate. It is a thing.

[0005]

The casting mold of the present invention, which has been made to solve the above-mentioned problems, comprises a pair of molds having air permeability which are matched to each other so as to form a molding cavity. In the casting mold, a straight tube portion is formed by coating a non-breathable film from the inlet of the casting passage of the slurry provided to open to the cavity to a substantially central portion, and the outlet of the casting passage from the straight tube portion. It is characterized in that it has an air-permeable slanted cylindrical portion that gradually expands its diameter.

[0006]

In the present invention thus constructed, after the slurry is poured from the casting passage into the molding cavity,
It is similar to the conventional casting mold of this kind in that it is dehydrated under pressure to be cast-molded, but an inclined cylindrical portion having air permeability is provided at the outlet of the casting passage. Since it is easy to remove the molded body filled inside, it is possible to reliably prevent the occurrence of biting, cracking and the like at the outlet portion when the molded body is released from the mold.

[0007]

The present invention will now be described in detail with reference to the illustrated embodiments. In the figure, 1a and 1b are a pair of upper and lower molds made of a material having air permeability such as ceramics and gypsum, 2 is a molding cavity formed by the molds 1a and 1b, 3
Is a casting passage provided in the molding die 1a corresponding to the upper die so as to pour the slurry which is the molding raw material into the molding cavity.

The casting passage 3 is formed as a straight cylindrical portion 5 which is covered with a non-breathable coating 4 such as metal, synthetic resin or plastic rubber from the inlet to the substantially central portion. A tubular pipe made of the above material may be attached. Also, the straight tubular portion 5
Is formed in the inclined cylindrical portion 6 having air permeability that gradually expands the diameter from the to the outlet of the casting passage, and the inclination angle θ of the inclined cylindrical portion 6 is 30 to 60 with respect to the cavity plane.
Further, the ratio (D2 / D1) of the inlet diameter D1 and the outlet diameter D2 of the casting passage 3 is set to 2 or more.
If the inclination angle θ is less than 30 °, the chipped portion may extend to the inside of the cavity that should be the product when biting occurs at the time of mold release. On the other hand, if it is more than 60 °, the dropout at the time of mold release occurs. This is because there is a risk that it may deteriorate and cause cracks and the like. Further, the inlet diameter D of the casting passage 3
Even when the ratio (D2 / D1) of 1 to the outlet diameter D2 is smaller than 2, there is a possibility that cracking may occur due to poor removal during release.

In the device constructed as described above,
The molding dies 1a and 1b are matched with each other, a molding raw material, for example, a slurry having a water content of about 40% is supplied into the cavity 2 through the casting passage 3, and then dehydrated while applying a pressure of 20 to 50 kg / cm ^2. The molded body 10 is cast-molded in the same manner as the conventional casting mold of this kind, but in the present invention, the casting passage 3 is used.
Since the straight cylindrical portion 5 is covered with the non-breathable coating 4 from the inlet to the substantially central portion, infiltration of this portion at the time of sludge injection is prevented, and a cavity is not generated in the cavity 2 sufficiently. The sludge will be supplied so that the meat can be ingested. After the molded body 10 having a predetermined shape is cast-molded in this way, blow air is supplied from the air pipe 7b to release the molding die 1b from the molded body 10, and then blow air is supplied from the air pipe 7a to form the molded body. The mold 1a is released from the mold 10. In this case, an inclined cylinder portion 6 having air permeability is provided at the outlet of the casting passage 3 to prevent the molding body from filling the casting passage. Since removal is facilitated, it is possible to reliably prevent the occurrence of bite at the outlet when the molded product is released. Further, the ease of releasing the part filled in the casting passage 3 is exactly the same as the part in contact with the other molding die 1a, and it has air permeability and is easy to remove from the air pipe 7a. As the blow air is supplied, the mold is released more smoothly, so the occurrence of cracks is surely prevented.
The molded product 10 of excellent quality can be efficiently manufactured. Note that the obtained molded body 10 is processed in a post-process in accordance with a conventional method to be a final product, as in the conventional case.

[0010]

As is apparent from the above description, the present invention reliably prevents the occurrence of biting, cracking, etc. at the time of mold release of a molded product after cast molding, and also in terms of external quality. It is possible to obtain a perfect molded product with no problems, and it is possible to efficiently manufacture a molded product with a high yield rate. Furthermore, it is improved only by applying a simple process to the conventional casting mold. It also has the advantage that it can be done. Therefore, the present invention is extremely large in that it contributes to the development of industry as a casting mold that eliminates the conventional problems.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 1a Mold 1b Mold 2 Mold cavity 3 Casting passage 4 Coating 5 Straight tube 6 Inclined tube

Claims (2)

[Claims] 1. A casting mold comprising a pair of air-permeable molds (1a), (1b) which are matched to each other so as to form a molding cavity (2), and are opened in the cavity (2). The straight pipe part (5) is covered with a non-breathable coating (4) from the entrance of the sludge casting passage (3) to almost the center part, and the casting passage is formed from the straight pipe part (5). The casting mold is characterized in that it has an air-permeable inclined cylindrical portion (6) that gradually expands its diameter toward the outlet of the. 2. The inclination angle θ of the inclined tubular portion (6) is set to 30 to 60 ° with respect to the cavity plane, and the ratio (D2 / D1) of the inlet diameter D1 and the outlet diameter D2 of the casting passage (3) is set. The casting mold according to claim 1, wherein the casting mold is two or more.