JPH05253914A - Extrusion molding of ceramic body - Google Patents

Abstract

PURPOSE:To solve twisting phenomena in the longitudinal direction of a cell wall in a honeycomb molded form by providing a strightening plate which has oblique holes in the direction reverse to the direction of the groove in the screw of an extruder between the screw for supplying body and molding dies. CONSTITUTION:A straightening plate 3 is engaged with the cylinder 6 of an extrusion molder. Through-holes of about 33 pieces are opened in the straightening plate 3. Body 2 used for molding has composition constituted of 70 parts beta-SiC of about 0.28mum average particle diameter, 30 parts alpha-SiC of about 1mum average particle diameter, 20 parts water, 6 parts methyl cellulose, 4 parts wax emulsion and 2 parts glycerin. Molding is performed in the conditions of about 80kg/cm<2> extrusion pressure and about 0.3 meter/min molding speed. As a result, warp is regulated within + or -0.5mm in length of about 150mm after molding, drying and burning. Thereby a peculiarity in the direction of rotation of a screw is completely solved by providing the straightening plate which gives rotation reverse to rotation of the screw.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous extrusion molding method for a ceramic kneaded clay, and more particularly to an extrusion molding method in which a "habit" during molding of an extrusion molded body is completely eliminated.

[0002]

2. Description of the Related Art It is well known that a ceramic kneaded clay extruded into a honeycomb structure and sintered has been used as a catalyst carrier in an automobile exhaust gas purifying apparatus or as a diesel particulate filter. Is.

In this honeycomb structure, the ceramic kneaded clay is continuously extruded by using, for example, an auger type extrusion molding machine as shown in FIG. That is, in FIG. 1, 6 is a cylinder, 1 is an extrusion screw, 4 is a honeycomb molding die, and the ceramic kneaded material 2 is extruded through the honeycomb molding die 4 by rotating the extrusion screw 1. The ceramic kneaded clay 5 which is extruded does not have a uniform flow to the die surface due to the influence of the screw, and causes a "habit" in the rotating direction of the screw that is extruded in the die direction. For this purpose, various methods have been tried, such as providing a rectifying plate for the rectifying plate, changing the hole diameter of the rectifying plate, or increasing the thickness of the rectifying plate to increase the resistance of the rectifying plate. It was However, in the case of molding a precise honeycomb body for a diesel particulate filter, for example, a sufficient effect has not been achieved.

[0004]

Therefore, the inventor of the present invention
As a result of various studies in order to solve the above problems, the kneaded material can be formed into a molded product having no "habit" by providing an inclined hole in the direction opposite to the groove direction of the screw of the extruder as the structure of the current plate. The present invention has been completed and the object of the present invention relates to an extrusion molding method in which the "habit" during molding is completely solved.

[0005]

Means for Solving the Problems The gist of the present invention is to form a ceramic kneaded clay by using an auger type continuous extrusion molding machine, in which a screw of an extruder is provided between a kneaded clay feeding screw and a molding die. A continuous forming method for a ceramic kneaded clay, characterized in that a straightening vane having inclined holes in a direction opposite to the groove direction is provided.

According to the present invention, the kneaded material is twisted and flows in the direction of the screw by the auger type extruder, whereas the flow of the kneaded material is prevented by providing the rectifying plate with an inclined hole so as to rotate the screw in the opposite direction. As it shows a flow parallel to the cylinder wall, it is possible to manufacture a molded product that completely eliminates the "habit" of the screw rotation direction. Then,
The auger type extrusion molding machine in the present invention refers to a method of using a screw for extruding kneaded clay, and the current plate is made of a steel plate having a thickness of 5 mm to 20 mm or the like and is usually used. It does not differ from anything. In the present invention, however, the straightening plate is provided with an inclined hole, and the inclination angle is preferably 1 ° to 45 ° with respect to the screw shaft of the extruder, and the effect cannot be expected at 1 ° or less. On the other hand, if it exceeds 45 °, twisting occurs in the direction opposite to the screw direction of the extruder, which is not preferable.

[0007]

EXAMPLE FIG. 1 is a schematic view showing an auger type extrusion molding method. 1 is a kneaded material extrusion screw, 2 is a kneaded material extruded by an extrusion screw, 3 is a straightening plate, 4 is a cell wall thickness of 12 millimeters (mil), and a cell density is 200 co / i
A honeycomb molding die having a square size of 30 mm on a side and having n ² , 5 is a molded body, and 6 is a cylinder of an extrusion molding machine. FIG. 2 shows an example of the current plate. It is die steel with a thickness of 12 mm, and the current plate is fitted in the cylinder 6 of the extruder. Then, 33 through holes having a hole diameter of 5 mm and an inclination angle of 20 ° are opened in the current plate.
The kneaded material used for molding is β-Sic with an average particle size of 0.28 μm.
70 parts, α-Sic 30 parts with an average particle size of 1 μm, water 20
Parts, methyl cellulose 6 parts Wax emulsion 4
And 2 parts of glycerin. Extrusion pressure 80kg /
As a result of molding under conditions of cm ² and a molding speed of 0.2 m / min, the bending after molding, drying and firing is 150 mm.
The length was within ± 0.5 mm. In addition, as a result of repeating the heating and cooling of the main body at room temperature to 1000 ° C. 30 times, “crack” and “bend” were not generated at all.

[0008]

As described above, according to the present invention,
By installing a straightening vane that has an inclined hole that gives a reverse rotation to the rotation of the screw, it is possible to completely eliminate the "habit" in the rotation direction of the screw. In the process, about 80% or more bends occurred, but in the present invention, the occurrence rate of bends is 1
It was 0% or less, and effects such as elimination of the twist phenomenon in the vertical direction of the cell walls of the honeycomb formed body could be obtained.

[Brief description of drawings]

FIG. 1 is a side sectional view of an auger type extruder.

FIG. 2 is a front view of a current plate used in the present invention.

FIG. 3 is a side view of a current plate used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extrusion screw 2 Kneaded clay 3 Straightening plate 4 Honeycomb molding die 5 Honeycomb molded body 6 Cylinder 7 Inclined hole

Claims (1)

[Claims] 1. When forming a ceramic kneaded clay using an auger type continuous extruder, an inclined hole in a direction opposite to the groove direction of the screw of the extruder is provided between the kneaded clay supplying screw and the forming die. A continuous forming method of a ceramic kneaded clay, which comprises providing the current plate.