JPH02102005A - Molding material purifier and ceramic molding method utilizing this purifier - Google Patents

Abstract

PURPOSE:To obtain a molded form which is free from a flaw and high in reliability by utilizing a perforated plate for reinforcing a screen wherein the respective molding material passages provided to the downstream side of the screen are formed into a tapered shape extended toward a body chamber formed between an extrusion mouthpiece and the perforated plate. CONSTITUTION:Side walls 6 for composing a body chamber 5 are fitted to one end of an equipment main body 1 while pinching both a screen 2 having prescribed mesh for removing foreign materials and a perforated plate 3 for holding the screen 2. A plurality of body passages 9 are provided to the perforated plate 3 and the tapers enlarged toward the clay chamber 5 are provided to the end parts of the respective body passages 9 in the body chamber 5 side. Thereby the body passed through the body passages is extruded along the inner surfaces of the taper-shaped body passages. As a result, component of force in the direction recetangular to the extrusion direction is caused and therefore the noodles extruded to the body chamber 5 from the body passages can be press-contacted and fused with each other. A molded form which is free from a flaw and high reliability can be obtained because the flaw such as a pore in the boundary between the noodles can be drastically reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a molding material refining device for molding a molding material such as a ceramic into a predetermined shape, and a ceramic molding method using the same.

(Prior Art) As an example of an extrusion molding apparatus used to form clay such as ceramic, an extrusion molding apparatus disclosed in US Pat. No. 3,888.963 is known. As shown in the cross section of FIG. 4, this extrusion molding apparatus attempts to supply molded bodies without defects by providing a clay flow equalizing device 22 upstream of the die 21. This equalizing device 22 consists of a screen 23 and a perforated plate 24 for reinforcing the screen provided downstream of the screen 23.
A plurality of clay passages 25 are provided on the perforated plate 24, and each clay passage 25 is chamfered on the screen side.

(Problem to be Solved by the Invention) However, in the conventional extrusion molding apparatus described above, the clay chamber 26 passes through the clay passage 25 of the perforated plate 24 and is located between the clay flow equalizing device 22 and the die 21. When supplying clay, since each clay passage 25 is straight, the force that causes the pieces of clay that have passed through adjacent clay passages 25 to fuse and become one, that is, the force in the direction perpendicular to the extrusion direction, is Since almost no force is generated, defects such as pores remain at the boundary between the noodles that have come out of the clay passage, and these defects remain in the molded product extruded from the die. the result,
The reliability of molded bodies obtained from conventional extrusion molding equipment has deteriorated, which has been a major problem, particularly when used as structural ceramic bodies.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a molding material refining device and a ceramic molding method using the same, which can produce defect-free and highly reliable molded bodies.

(Means for Solving the Problems) The molding material refining device of the present invention includes a cylinder installed on the upstream side of a molding die for obtaining a molded body, and a molding material refining device installed in the cylinder with a screen installed on the downstream side of the cylinder. It consists of a perforated plate for reinforcing the screen, and is characterized in that each molding material passageway of the perforated plate has a tapered shape that widens toward the clay chamber formed between the molding die and the perforated plate. .

Further, the molding method of the present invention provides screen reinforcement in which the above-mentioned screen and each molding material passage provided on the downstream side thereof have a tapered shape that widens toward the clay chamber formed between the extrusion die and the perforated plate. It is characterized in that it is molded by means such as compaction molding and injection molding using a molding material refining device consisting of a perforated plate.

(Function) In the above-described configuration, the screen functions to remove foreign matter from the molding material. Since the strength of the screen itself is low, a perforated plate is required as a reinforcing material. By making each clay passageway of the perforated plate into a tapered shape that widens toward the clay chamber, the clay that has passed through the clay passageway is extruded along the tapered inner surface of the clay passageway, and as a result, the clay passageway is perpendicular to the extrusion direction. Since a component force in the direction is generated, the noodles pushed out from the clay passageway into the clay chamber can be pressed and fused together, and this can solve the problems that could not be solved with conventional clay flow equalization devices. Since defects such as boundary pores can be significantly reduced, a defect-free and highly reliable molded product can be obtained.

The screen for collecting foreign matter in the molding material used here has a smaller opening, which is preferable for removing small foreign matter.
The size of the screen can be selected depending on the clay. The angle of the taper is in the range of 150 to 3 degrees, preferably 90 to 1
A range of 0° is preferred. Also, the taper angle is 150°
If the angle is more than 3 degrees or less than 3 degrees, the component force in the direction perpendicular to the extrusion direction becomes small, and as a result, gaps are formed between the noodles and defects are likely to occur. In addition, it is preferable for the tapers to overlap on the mold side end surface of the taper in order to improve noodle crimping, but the area where they do not overlap, for example, the flat part 9-2, is 30% of the total area of the taper part and the flat part. % or less, preferably 10% or less. When the non-overlapping area is 30% or more, gaps are created between the noodles and defects are likely to occur.

(Example) FIG. 1 is a sectional view showing the configuration of an example of an extrusion molding refining apparatus of the present invention. In the embodiment shown in FIG.
At one end, a molding material homogenizing device 4 consisting of a screen 2 of a Tyler standard sieve 80 mesh for removing foreign matter and a perforated plate 3 for supporting the screen 2 is sandwiched between the two to define a clay chamber 5. A side wall 6 is attached for this purpose.

Further, a cap 8 is attached to one end of the side wall 6 via a cap holder 7. A plurality of clay passages 9 are provided in the perforated plate 3,
The end of each clay passageway 9 on the clay chamber 5 side is provided with a taper that expands toward the clay chamber 5.

FIGS. 2(a) and 2(b) are views showing the perforated plate 3 of the present invention viewed from the direction of FIG. 1, respectively. Figure 2 (
In the example shown in a), each clay passage 9 is provided with a tapered portion 9-1 so that all portions are tapered. In the example shown in FIG. 2(b), each clay passageway 9 has a second
Similar to the example shown in Figure (a), a tapered portion 9-1 is provided, and a non-tapered flat portion 9-2 is also provided.

FIG. 3 is a cross-sectional view for explaining the shape of the clay passage and part of the taper in the perforated plate 3 of the present invention.

Using this perforated plate, an extrusion molding device equipped with a forming material refining device shown in FIG. 1 was manufactured. A clay having a predetermined composition such as silicon nitride or silicon carbide is supplied into the device main body 1, and the clay is pushed out with a plunger or the like (not shown). Foreign matter is removed from the extruded clay by a screen 2 of 80 mesh Tyler standard sieve installed in the molding material refining device 4, and the clay is continuously supplied to the clay chamber 5 through the clay passage 9 of the perforated plate 3. After being made into a carpact, a molded article having a predetermined shape could be obtained from the die 8.

The yield of the molded product extruded by the extrusion device of the present invention is 9
It was high at 8%, and almost no defects occurred.
The yield of molded bodies extruded using the conventional extrusion device shown in Figure 4 is as low as 30%, and the molded bodies have defects ranging from 0.2 mm to 5 mm per molded body caused by insufficient pressure bonding between the noodles. 15 cases were detected.

Furthermore, when the present invention was applied to injection molding, similar effects were obtained.

(Effects of the Invention) As is clear from the above description, according to the molding material refining device of the present invention and the ceramic molding method using the same, the upstream side of the molding die is equipped with a screen for removing foreign matter and a reinforcing screen. Moreover, by assembling perforated plates that do not cause defects so that each clay passage has a tapered shape that widens toward the clay chamber, the crimpability of the clay is improved, and since a sieve is provided on the upstream side of the perforated plates. This method has the effect of removing foreign matter, and it is possible to obtain a highly reliable molded product with few defects.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the configuration of an example of an extrusion molding apparatus of the present invention, FIGS. Fig. 3 is a sectional view for explaining the shape of the clay passageway and part of the taper in the perforated plate of the present invention, and Fig. 4 is a sectional view showing the configuration of an example of a conventional extrusion molding device.・Device body 2...Screen 3...
・Perforated plate 4... Molding material refining device 5...
- Clay chamber 6... Side wall 7... Aperture ring 9... Clay passage 9-2... Flat part 8... Mouthpiece 9-1... Taper part 4X# material mold attack 1

Claims (1)

[Claims] 1. A cylinder provided upstream of a molding die for obtaining a ceramic molded body, and a molding material refining device installed in the cylinder, consisting of a screen and a perforated plate for reinforcing the screen provided downstream thereof. A molding material refining device characterized in that each clay passageway of the perforated plate has a tapered shape that widens toward a clay chamber formed between the mold and the perforated plate. 2. A ceramic molding method, characterized in that molding is carried out using a molding material prepared using the molding material refining device according to claim 1.