JPH0485004A - Pressure molding device for closed-end cylindrical kneaded material - Google Patents

Abstract

PURPOSE:To improve the release properties of a closed-end cylindrical kneaded body by providing a recessed section for air vent on the outer peripheral face of an inner mold. CONSTITUTION:Paste is fed into a cylindrical hole 7 in an outer mold 5 and an inner mold 6 is lowered while being rotated in the arrow A direction and from above the paste, and then the inner mold 6 is lifted up while being rotated. After that, the outer mold 5 is parted to an outer mold 5a and an outer mold 5b, and a molded product is released from the inside of outer mold 5. As surplus paste is discharged through a recessed section for air vent provided in the inner mold when the inner mold 6 is lowered, and the molding pressure is applied uniformly. Also, as the inner mold 6 is lifted up and the paste is discharged while the mold is rotated, air is exhausted along the surface of equal sides 9. Thus the interface of the inner mold and a molded body is not stuck with the water content in the paste or not formed into the vacuum state as is in the case of lacking the recessed section for air vent. The molded product, therefore, is not adhered to the inner mold 6. Also, as compulsory force is not applied to the molded body, decentering of the molded product is small to make good dimension accuracy. Also, when the mouter molds 5a and 5b are parted after pressure molding, recesses, defective R shape, cracks or the like are not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an apparatus for press-forming a kneaded material into a bottomed cylindrical molded product.

(Prior art) In general, the method for manufacturing bottomed cylindrical ceramics is as follows:
There are methods such as ■ extrusion molding of kneaded clay, ■ casting molding of mud, and ■ pressure molding of powder.

For example, when making a bottomed cylindrical porous ceramic filter for filtering liquids, the clay is pressure-molded and the size is, for example, length: 94 mm, outer diameter 34 mm, inner diameter 20 mm.
Pressure molded into a cylindrical body with a bottom. An example of this device is shown in FIG. 3.

This pressure molding device fills the inside of the outer mold l with clay,
After lowering the middle mold 2 from above and pressing, the middle mold 2 is raised, the outer mold 1 is divided into 1a and 1b, and the bottomed cylindrical molded body is extracted from the cylindrical hole 1c of the outer mold 1. It is.

(Problem to be Solved by the Invention) However, according to such a conventional press-forming apparatus for a kneaded product in a bottomed cylindrical shape, mold removal after pressurization is difficult based on the shape of the molded product, which is a bottomed cylindrical body. Since it is difficult to release the molded product, there are the following problems.

■ For example, as shown in Fig. 4(a), the molded product (mixed clay) 3 easily adheres to the outer peripheral surface of the cylindrical medium mold 2;
cannot be removed from medium size 2.

■ As shown in Figure 4(b), the molded product 3 easily adheres to the inner peripheral surface of the outer mold 1, so if the outer molds 1a and 1b are separated and released in the direction of the arrow, the molded product 3 will deform. or cracks may occur.

■ As shown in Fig. 4(c), when the middle mold 2 is released from the mold, when the middle mold 2 is raised in the direction of the arrow, the inside of the cylinder of the molded product 3 and the middle mold 2
A vacuum portion (3) is generated between the two, causing a dent 3a on the outside of the molded product 3, and a defective rounded shape at the tip of the molded product.

The present invention was made to solve these problems, and it improves the mold release property during pressure molding, and does not damage the dents or R shape of the molded product (it is possible to create a bottomed cylinder with high dimensional accuracy). It is an object of the present invention to provide a pressure molding apparatus for a kneaded product in a cylindrical shape with a bottom, which can produce shaped molded products with high production efficiency.

(Means for Solving the Problems) For this purpose, the press forming apparatus for a kneaded product in a bottomed cylindrical shape of the present invention includes an outer mold having a cylindrical hole, and a kneaded material filled in the cylindrical hole, which is pressed and The present invention is characterized in that it is composed of a medium-sized rotary body that rotates and has an air vent recess on the outer peripheral surface of the rotary body.

As the kneaded material, ceramics such as oxides, carbides, and nitrides such as aluminum, zirconium, and titanium, glasses such as borosilicate glass, and metals such as nickel can be used.

(Function) According to the pressure molding apparatus for the bottomed cylindrical kneaded product of the present invention, the medium mold is rotated and the air venting recess is provided on the outer peripheral surface of the medium mold, so that the air venting recess is not removed when the medium mold is demolded. Since the air escapes, a vacuum region is not generated for the kneaded material packed in the cylindrical hole of the outer mold. .

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a pressure molding apparatus, and in the figure, 5 indicates an outer mold, and 6 indicates a middle mold. The outer mold 5 is a half-split type of an outer mold 5a and an outer mold 5b, and has a cylindrical hole 7 inside and a stepped large diameter hole 8 above the cylindrical hole. The middle mold 6 can be inserted into the cylindrical hole 7 of the outer mold 5, and has a hemispherical convex tip 6a.

As shown in FIG. 2(c), the main body of the medium-sized body 6 shown in FIG. R is added to the boundaries of adjacent 9's as appropriate, and these 9's as appropriate constitute recesses for air venting with respect to the circumscribed circle.

The pressure molding method will be explained based on Fig. 1.
Mixed soil is put into the cylindrical hole 7 inside the outer mold 5, and the middle mold 6 is lowered from above the mixed soil while rotating in the direction of the first arrow shown in the figure, and after pressing, the middle mold 6 is raised while rotating.

After that, the outer mold 5 is divided into an outer mold 5a and an outer mold 5b, and the outer mold 5 is divided into an outer mold 5a and an outer mold 5b.
Take out the molded product from inside.

In this case, when the middle mold 6 is lowered, excess kneaded soil is discharged through the recessed portion of the air vent provided in the middle mold, so that the molding pressure acts uniformly. In addition, since the medium mold 6 is raised and extracted while rotating, the air is released along the line 9 as appropriate. In other words,
Air venting prevents the interface between the medium mold and the compact from sticking to moisture in the mixed soil or creating a vacuum state, unlike when there is no recess.

Therefore, the molded product is not adhered to the middle mold 6. Furthermore, since no unreasonable force is applied to the molded product, the misalignment of the molded product is small and the dimensional accuracy is good.

Furthermore, when the outer mold 5a and the outer mold 5b are separated after pressure molding, no dents, R-shaped defects, cracks, etc. will occur in the molded product.

Next, as another embodiment of the present invention, modified examples of the cross-sectional shape of the middle mold 6 are shown in FIGS. 2(d), (e), and (f). (d) is the outer peripheral surface of a medium-sized cylindrical body, with three sides spaced at 120" intervals.
0 and a circular arc surface 14 are formed, (e) is a medium-sized cylindrical body with four sides 11 and circular arc surfaces 15 formed as appropriate at 90° intervals on the outer peripheral surface, and (f) is a Curved surfaces I2 whose outer diameters are gradually reduced in the circumferential direction are formed on the outer circumferential surface of the cylindrical body of the medium size 6 at equal intervals every 90 degrees.

Also, as comparative examples, (a) is a medium-sized 6 with a circular cross section, (b)
is a medium mold 6 having a circular cross section and two grooves 13 and 14 formed in the diameter direction.

Next, regarding the examples and comparative examples shown in Fig. 2, we categorized them according to the presence or absence of rotation of the medium mold, the presence or absence of addition of a release agent to the medium mold, and the softness or hardness of the material kneaded material, and when using each medium mold. The molding results are shown in Table 1.

(The following is a margin.) In Table 1, "soft" in the hardness of the material indicates that it is hard enough to eliminate wrinkles when you squeeze the soil with your hands, and "hard" indicates that the material is hard enough to remove wrinkles when you squeeze the soil with your hands. It is hard enough to cause wrinkles.

As is clear from Table 1, in Examples 1 to 9 of the present invention, molding and mold release could be performed, and the molded bodies were not deformed, or even if deformed, the deformation was small. On the other hand, in Comparative Examples 1 to 6, the molding results were such that the middle mold did not come out and cracks occurred in the molded product.

Furthermore, Figures 5, 6 and 7 show how the product according to the present invention has excellent moldability and mold release properties.
This will be explained in comparison with the comparative example shown in the figure.

In Comparative Example 10 shown in FIG. 5, pressurized air is supplied into the cylindrical hole 7 through the hole 5a having an inner diameter of about 1 mm in the outer mold 5 during mold release. In this case, a draft slope S is added to the cylindrical hole 7 with a slope value of 0.25/80. According to this comparative example, the molded soil entered the holes 5a during molding, and some of the molded products could not be released, and buckling of the molded products occurred frequently.

In Comparative Example 11 shown in FIG. 6, the molded product 3 after molding is subjected to vacuum suction to release the molded product 3 upward as indicated by the arrow. In this case, the cylindrical hole 7 has a draft angle of 0.25/
80 is added. In the case of this comparative example, the degree of vacuum is 76
Even at 0 mmHg, the molded product cannot be released from the mold, and the outer mold 5
Buckling occurred inside. After 3 minutes of drying with a dryer, the vacuum level was set to 760 mmHg, but it was not possible to release the mold.

Comparative Example 12 shown in FIG. 7 is press-molded with the middle mold 2 slightly eccentric to the outer mold 5 to improve mold releasability. According to this comparative example, compared to the conventional example without eccentricity shown in Fig. 3, the incidence of adhesion of the molded product to the outer peripheral surface of the medium mold 2 was considerably reduced, but misalignment and uneven thickness of the molded product occurred. However, the dimensional accuracy deteriorated.

Furthermore, in Comparative Example 13 (not shown), various comparative tests were conducted by changing the type and amount of the mold release agent, but it was found that the mold release effect did not change significantly depending on the type of mold release oil.

Furthermore, when the amount of mold release oil applied was small, the mold release properties deteriorated and the molded product adhered to either the middle mold or the outer mold. This confirmed that the mold release effect was improved by applying a mold release agent to the middle or outer mold. However, it has not been possible to effectively improve mold releasability only by applying a mold release agent.

(Effects of the Invention) As explained above, according to the pressure molding apparatus for a bottomed cylindrical kneaded product of the present invention, the medium mold is rotated to perform pressure molding, and the concave portion for air venting during pressure molding is formed. This has the effect that the bottomed cylindrical molded product after molding can be reliably released from the mold, and that the molded product obtained by pressure molding is only slightly deformed and has high dimensional accuracy.

A cross-sectional view of the pressure molding device for explaining the illumination point, FIG.
FIG. 6 and FIG. 7 are cross-sectional views showing a pressure molding apparatus of a comparative example.

...outer mold, ...Medium size, ...Cylindrical hole, ... Equally transparent surface (concavity for air release).

Claims (1)

[Claims] (1) Consisting of an outer mold having a cylindrical hole, and a rotating body that rotates while pressing against the kneaded material filled in the cylindrical hole, and a middle mold having an air vent recess on the outer peripheral surface of the rotary body. 1. A press-forming device for a kneaded product in a bottomed cylindrical shape.