JP2003266420A - Method for vertical extrusion molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for molding a molded product which extrudes while a deformation is depressed and which can cut without distorting an internal structure. <P>SOLUTION: The method for vertical extrusion molding comprises the steps of: continuously extruding a molded product downward, cutting the product at a cutting position when it becomes a predetermined length from the cutting position, imparting a reaction force of an amplitude in response to an extruding length until it becomes a predetermined length to a lower end face of the product, changing to a reaction force to well cut when the length becomes a predetermined length, and starting cutting. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a molded body extruded by a vertical extrusion method, and more particularly to a molding method suitable for a ceramic honeycomb molded body.

[0002]

2. Description of the Related Art As an extrusion molding method for a molded body, a horizontal extrusion molding method of laterally extruding is mainly used. The horizontal extrusion method has an advantage that it can be easily automated because setting in a subsequent process is convenient. However, if the weight of the molded body is greater than the strength of the molded body, the molded body is deformed by its own weight, and it is difficult to obtain a product with good dimensional accuracy. In the formed article having a honeycomb structure, a large number of cells surrounded by thin partition walls are formed, but when the partition walls are deformed, the cell shape is also deformed, and it becomes difficult to obtain a predetermined product performance. In particular, in a honeycomb formed body made of ceramic used for a catalyst carrier of an automobile exhaust gas purification system, since exhaust gas flows through the cells, it is required that local deformation and protrusion of partition walls be as small as possible. In order to solve this, a vertical extrusion molding method has been proposed in which a ceramic molded body is extruded in a vertical direction. For example, JP-A-63-230304 (known example 1) extrudes downward through an extrusion die. It is disclosed that an extruded molded body is cut into a predetermined length by preventing the deformation of the extruded molded body by applying a reaction force to the molded body and holding it. As a method of generating a reaction force, a method of controlling the fluid pressure of the plunger supporting the pedestal for holding the molded body by measuring the extrusion length of the molded body or a measured value proportional to it, or A method for detecting such a force and controlling the position of the pedestal so that the force is proportional to the length of the molded body is described.

Further, various cutting techniques have been disclosed for cutting an extruded ceramic compact without distortion and for increasing the cutting efficiency. For example, JP-A-6-
No. 270092 (Known Example 2) discloses a method of cutting a laterally extruded molded body by traversing with a wire, in which a wire tensioned between two pulleys is tensioned by a spring and Also disclosed is a method of cutting by relatively increasing the speed in the pulling direction. Further, JP-A-2000-296497 (known example 3)
Similarly, in the method of cutting the horizontally extruded molded body by traversing with a wire, the tensile force of the wire is controlled by controlling the torque of the servo motor to the wire stretched between the bobbins provided in the two servo motors. A method of running and cutting while applying a tension not exceeding is disclosed.

[0004]

In order to obtain a molded body having internal partition walls, in particular, a ceramic honeycomb molded body used for a catalyst carrier of an automobile exhaust gas purification system, without extruding the partition wall portions, extrusion is performed. It is important to avoid deformation at times and not to crush the partition wall during cutting. In the known example 1, there is a description about a technique for preventing the deformation of the extruded compact, but there is no detailed description about cutting the compact except that a thin wire is used. .
That is, the reaction force applied to prevent the deformation of the extruded compact is proportional to the extrusion length of the compact, and its maximum value does not exceed 5 times the weight of the compact of a predetermined length. It is described that the range is set. This means that, for example, when the reaction force is 5 times the weight of the molded body, a compression force of about 4 times the weight of the molded body is acting on the cut portion of the molded body near the die of the molding machine. . Therefore, when cutting,
The resistance that the wire receives when passing through the molded body is large,
In order to cut the partition wall sharply without crushing it, it is necessary to apply a large amount of tension to the wire having a small diameter.
Therefore, it is presumed that the wire will break or the life will be shortened. In addition, as cited in the publicly known examples 2 and 3, all of the conventional molded body cutting techniques are intended for laterally extruded molded bodies, and the molded body having its own weight supported is cut with a wire from the direction of gravity. The load related to the weight of the molded body does not act on. When these techniques are actually applied to the vertical extrusion molding, it is difficult to cut the outer peripheral wall and the partition wall without deforming the molded body because its own weight is applied. It is an object of the present invention to provide a molding method for obtaining a molded product by extruding while suppressing deformation and cutting the internal structure so as not to distort, in the vertical extrusion method.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a vertical pressing molding method in which a molded body is continuously extruded downward and cut when the molded body reaches a predetermined length. It is characterized in that it is supported by a reaction force having a magnitude corresponding to the extruded length of the molded product until reaching the predetermined length, and is supported by a reaction force which allows good cutting when cutting the molded product. Further, the present invention, the molded body is continuously extruded downward,
In the vertical pressing molding method in which the molded body is cut when it reaches a predetermined length, the weight of the molded body extruded is calculated based on the extruded length, and the lower surface of the molded body becomes the predetermined length of the molded body. Up to the reaction force controlled so as to increase according to the extruded weight of the molded product, and at the time of cutting the molded product it is supported by the reaction force controlled to the set value based on the weight of the molded product. It has a feature. In the present invention, at the time of starting the cutting of the molded body, it is preferable to support the molded body with a reaction force such that an incompressible stress acts on the portion to be cut. Further, in the present invention, when the molded body has a predetermined length, the fine wire to which the tension is applied is moved in the forward direction to cut the molded body, and when the next molded body has the predetermined length, It is preferable to repeat the cutting operation of moving in the backward direction and cutting the molded body. Further, in the present invention, a jig having a fluid vent hole on the surface and capable of moving between steps is supplied below the molded body, and a reaction force is applied to the lower surface of the molded body extruded through the jig. It is preferable to carry out the molded body together with the jig after the cutting is performed.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a vertical extrusion molding apparatus according to an embodiment of the present invention. The molding apparatus includes a molding machine 1 having a die (not shown) for forming the molded body 2, and an elevator 10 that is means for applying a controlled reaction force to the molded body 2.
And a jig 3 placed on the elevator 10 and in contact with the molded body 2, and a cutting machine 20 for cutting the extruded molded body 2 into a predetermined length. In this embodiment, a conveyor 4 that carries the jig 3 on which the cut molded body 2 is placed to the next step, a conveyor 5 that carries an empty jig 3 from the next step, and an elevator around the molding apparatus. 10 and handling devices 6 and 7 for transferring the jig 3 between the conveyors 4 and 5 are provided.

The molding machine 1 is a vertically-pressing molding machine for extruding a slurry containing ceramic downward through a die to mold a ceramic honeycomb body having a substantially cylindrical outer shape, for example. The jig 3 supports the molded body 2 that is supplied and set to the elevator 10 and is extruded from the molding machine 1. The jig 3 has a rectangular shape or a circle shape on which the molded body after cutting can be directly placed and conveyed to the next step. Is a substantially flat body. The surface of the jig 3 is formed so that the cells inside the molded body are in fluid communication with the external space so that the molded body to be extruded is not deformed, and the molded body 2 does not easily lie sideways. That is, it is preferable to form a large number of air circulation holes through the surface or to use a porous material.

The details of the elevator 10 are shown in FIG. 2. The elevator 10 is provided with a rectilinear table 11 which is driven in the vertical direction, a vertical compliance means 12 which is installed thereon, and a pedestal 13 which is supported by the compliance means 12. And
The jig 3 is placed on the upper surface of the pedestal 13. Straight ahead table 1
Reference numeral 1 is connected to a ball screw 14 driven by a servo motor (not shown), and the position and speed are controlled. The compliance means 12 in the present invention can set a desired reaction force regardless of the displacement amount, and it is preferable to use, for example, an air cylinder. In this embodiment,
A low friction cylinder (hereinafter simply referred to as cylinder 12) having a built-in linear sensor and capable of detecting a displacement amount is used as the compliance unit 12, and an electropneumatic regulator is connected to control the output of the air cylinder 12 by an electric signal. I chose The pedestal 13 attached to the tip of the rod of the cylinder 12 can be moved straight up and down by a guide mechanism according to the movement of the rod, and the amount of movement can be detected by a linear sensor built in the cylinder 12. it can.

The cutting machine 20 has a cutting unit 30 in which a very fine piano wire (hereinafter referred to as a thin wire) 26 for cutting the molded body 2 is stretched substantially horizontally. ) And orthogonal two-axis moving means that can move straight in a direction (horizontal direction) orthogonal thereto and are configured so that the position and speed can be controlled by the servomotors 21 and 22, and the molded body 2 being extruded is cut horizontally. You can The cutting machine 20 is arranged at a position where the extruded molded body 2 can be cut at a position close to the die of the molding machine 1.

The cutting unit 30, as shown in FIG.
On the base portion 31b of the U-shaped flange 31, the feeding bobbin 32 for feeding the thin wire 26 and its rotating means 33, and the thin wire 26.
A winding bobbin 34 and a rotating means 35 for winding the same, and a tension applying means 36 for applying a tension to the thin wire 26 are provided, and one branch portion 31u of the flange 31 and the other branch portion 31d are
A plurality of pulleys 37 that form a traveling path of the fine wire 26, and a wiper 38 that removes the chips of the molded body adhered to the fine wire 26.
Is provided. The thin wire 26 is fed from the feeding bobbin 32, and the pulley 37a and the pulley 37b provided at the tip of one branch 31u of the flange change the direction by the pulley 37c, and the pulley 37d provided at the tip of the other branch 31d, the pulley 37e. A running path is formed that leads to the take-up bobbin 34 via the pulleys 37f and 37g provided on the tension applying means 36, the pulleys 37h and 37i provided on the flange 31, and the pulleys 37i.

The tension imparting means 36 imparts a predetermined tension for cutting the molded body 2 to the fine wire 26, for example, a low friction air cylinder connected to a precision pressure control valve or a constant force. It is good to use such a special spring. In this embodiment, a low-friction cylinder (hereinafter simply referred to as a tension cylinder 36) having a built-in linear sensor and capable of detecting a displacement amount is used. A tip fitting 38, to which two pulleys 37f and 37g are fixed, is attached to the rod tip of the tension cylinder 36. In this embodiment, tension is applied to the thin wire 26 by controlling the output of the tension cylinder 36 on the rod return side. The tip fitting 38 is provided on the feeding bobbin 32.
Or when the winding bobbin 34 is not rotating, or the molded body 2
When is not cut, the wire 26 is stopped at an appropriate position while applying a predetermined tension to the thin wire 26. This stop position can be detected by a built-in linear sensor.

The molded body 2 is cut at the portion of the thin wire 26 which is passed to the tips of both branch portions 31u and 31d of the U-shaped flange 31. When the thin wire 26c of this portion is pushed from the direction of arrow A in FIG. 3, it is supported by a pulley 37b provided at the tip of one branch 31u and a pulley 37e provided at the tip of the other branch 31d, and conversely the arrow When pushed from the direction B, the pulley 37c provided at the tip of one branch 31u and the pulley 37d provided at the tip of the other branch 31d are arranged to be supported. Therefore, the cutting can be performed at any time of the reciprocating operation of the cutting unit 30 (for example, when the cutting unit 30 moves so as to approach the molded body 2, the forward operation is performed, and the cutting unit is moved away from the molded body 2). If you want to move to the return operation). Further, the feeding bobbin 32 and the winding bobbin 34 are appropriately rotated, and the thin wire 26c for cutting the molded body 2 is newly updated, whereby the cutting of the thin wire can be prevented.

Next, the molding operation will be described with reference to FIG. First, the initial position of the elevator 10 is set. Air of a predetermined pressure is supplied to the cylinder 12 provided on the straight-moving table 11, the pedestal 13 on which the jig 3 is mounted is raised, and the origin of the cylinder 12 is set at the time of rising, and the cylinder 12 is built in at this time. The read value of the linear sensor is read and stored in the storage unit of the control device 8. In this state, the rectilinear table 11 is moved upward so that the upper surface of the jig 3 moves to
As shown in (a), when the fine wire 26 of the cutting machine 20 reaches the same level as the position (X1) at which the molding 2 is cut, the origin of the straight advance table 11 is set, and the position sensor value of the servo motor at this time is set as It is read into the storage unit of the control device 8. The initial position of the elevator 10 is when both the cylinder 12 and the straight advance table 11 are at the origin. The origin positions of the cylinder 12 and the straight advance table 11 can be set arbitrarily, and even if both are at the origin, the initial position of the elevator 10 does not have to be the initial position. The point is that the positional relationship between the upper surface of the jig 3 and the reference position of the molding machine 1 or the cutting machine 20 at the initial position may be defined.

Next, the initial position of the cutting machine 20 is set. The position sensor value of the servo motor 21 is defined as the origin of the cutting unit 30 in the vertical direction when the cutting unit 30 is moved by the servo motor 21 in the vertical direction and the fine wire 26 reaches the position (X1) where the thin body 26 starts to cut. Is stored in the storage unit of the control device 8. The cutting start position X1 is preferably set near the tip of the molding machine in a range where the cutting unit 30 does not contact the tip of the molding machine 1. Next, the cutting unit 30 is moved in the horizontal direction by the servomotor 22, and the thin wire 26c passed to both branches at a position where the U-shaped flange 31 does not intersect the molded body is shown in FIG. 4 (a). As described above, when it comes to a position where it does not come into contact with the surface of the molded body that is separated from the axial center of the molded body 2 to be extruded by a predetermined distance R, the cutting unit 3
With the horizontal origin of 0, the position sensor value of the servo motor 22 is read and stored in the storage unit of the control device 8. Cutting machine 2
The initial position of 0 is set when the cutting unit 30 is at the vertical origin and the horizontal origin.

When the extrusion operation of the molded body is started, FIG.
As shown in (b), the elevator 10 has a cylinder 12
With the origin being maintained, the linear table 11 is lowered by a distance S from the origin, and the jig 3 mounted on the pedestal 13 is moved downward by a predetermined distance S from the initial position to stand by. Molding machine 1
When the molded body 2 extruded from the molded body 2 extends downward and reaches the length S from the molded body cutting position X1, the lower end of the molded body contacts the jig 3, and the rod of the cylinder 12 at the rising end is retracted. When the rod of the cylinder 12 moves to a predetermined value, for example, half of the stroke, the straight advance table 11 starts descending at a speed synchronized with the extrusion speed of the molded body 2. Molded body 2
Although the extrusion speed of the above may fluctuate somewhat due to resistance when passing through the die, it is absorbed by the vertical movement of the cylinder 12.

During this time, the lower surface of the molded body 2 is supported by the reaction force determined by the air pressure supplied to the cylinder 12 from the upper surface of the jig 3. When the self-weight and the reaction force of the molded body 2 are different, the difference acts as a tensile force or a compressive force in the vicinity of the die of the molded body 2. There is no particular problem if this difference is a substantially constant value irrespective of the self-weight of the molded body 2 and does not cause the molded body 2 to be constricted or buckled. This may cause necking and buckling. Therefore, it is preferable that the reaction force be increased in accordance with the increase in the weight of the extruded molded body 2. The weight of the molded body 2 can be calculated based on the extrusion length if the weight per unit length is known. In this embodiment,
As shown in FIG. 4C, the length from the cutting start position X1 to the upper die part is constant at K, and the length L0 from the cutting start position X1 to the lower part is the movement of the jig 3. Since it can be measured by the amount, that is, the total value of the movement amounts of the cylinder 12 and the straight advance table 11, the weight can be obtained from the length of K + L0.

If the weight at an arbitrary extrusion length is calculated, the reaction force corresponding to this can be obtained by controlling the air pressure supplied to the cylinder 12. The air pressure can be controlled by an electric signal to the electropneumatic regulator, and can be calculated and output based on the movement amount L0 of the jig 3. In addition, this reaction force is generated when the lower surface of the molded body 2 is the jig 3
It produces a frictional force that suppresses displacement from the upper surface, and prevents the molded body from bending or twisting. As described above, the jig 3 is devised to increase the frictional force, such as having a large number of concave portions on the surface, but it is effective that the reaction force of the jig 3 is large. Further, in order to make the density inside the molded body 2 uniform, it is preferable that the compression force acts. How much the reaction force should be depends on the use of the molded product, the material and properties of the slurry, and the compression strength resulting from the difference in shape such as the ratio of the cross section to the length of the molded product. It is advisable to apply a reaction force 1.3 to 2 times the weight of the extruded portion in accordance with the change in the weight of the molded product due to the change. Even if the lower surface of the molded body 2 is in contact with the jig 3, the cells inside the molded body 2 communicate with the outside through the fluid flow holes of the jig 3, so that the inside of the cell will be greatly negative pressure. There is no deformation for that.

When the molded body 2 reaches the set predetermined length, cutting is started. The cutting unit 30 moves forward in the horizontal direction at a predetermined speed, and immediately before the thin wire 26 comes into contact with the molded body 2, the cutting unit 30 starts descending at a speed determined by the extrusion speed of the molded body 2 and the forward speed of the cutting unit 30 to form the molded body. Cut 2 so that it is parallel to the lower end surface. In cutting, it is preferable that the cutting resistance is small because the cutting surface is sharp, the cutting time is short, and breakage of thin wires can be prevented. As described above, when a reaction force is applied to the molded body 2 so that a compression force acts, the compression force acts on the portion to be cut, and if it is cut as it is, cutting resistance is large. Therefore, at the time of cutting, the reaction force is controlled so that the portion to be cut receives almost no compressive force, for example, a tensile force acts. This can be performed by outputting a predetermined electric command to the electropneumatic regulator so as to give a predetermined reaction force smaller than the extruded weight of the portion to be cut of the molded body 2 and below. However, if the tensile force is applied until the end of cutting, the tensile stress of the surface that has not been separated increases, and there is a risk that the surface will be torn before it is cut. Therefore, when the cutting is started, it is preferable to control the reaction force so that the uncut surface is not broken by the tensile stress. For simplicity, the reaction force may be made substantially equal to the extruded weight below the portion to be cut after a predetermined time has elapsed from the start of cutting.

When the cutting is completed, the linear table 11 descends at a high speed, and the jig 3 holding the molded body 2 cut to a predetermined length is carried out from the receiving table 13 to the conveyor 4. Since a frictional force that is unlikely to laterally shift acts on the contact surface between the jig 3 and the molded body 2, the molded body 2 does not largely shift during transportation. After that, when a new jig 3 is placed on the pedestal 13 from the conveyor 5, the linear table 11 moves up at a high speed, stops at a predetermined position below the initial position of the elevator 10 by a predetermined distance S, and continuously. Stand by to support the flat lower end of the new molded body 2 being extruded. The predetermined distance S is the extrusion speed of the molded body 2, the descending speed of the rectilinear table 11, the time for replacing the jig 3, and the ascending speed of the rectilinear table 11, and the jig 3 on the rectilinear table 11 is extruded. The position in contact with the molded body 2 may be obtained in advance and appropriately determined based on this.

When the cutting unit 30 is advanced in the horizontal direction to cut the molded body 2 (forward operation), the cutting unit 30 is lifted while being stopped at the forward end, returned to the origin position only in the vertical direction, and waits. . During this time, the next molded body is extruded so as to pass between the both branch portions 31u and 31d of the U-shaped flange 31. Therefore, in the next cutting, the cutting unit 30 retracts in the horizontal direction (return operation) to perform the cutting operation. In this way, when a continuous molded body is cut while repeating the forward and backward movements of the cutting unit 30, the thin wire 26c is cut into the molded body 2 as in the case of cutting only from one direction.
It is not necessary to return the unit 30 so that it does not hit, and there is no fear of trouble that the thin wire comes into contact with the molded body. Further, since the molded body 2 is cut with a small cutting resistance, it is not necessary to run the thin wire 26 during cutting. After the cutting is performed an appropriate number of times, the rotating means 20 and 21 are driven to change the thin wire portion used for cutting the thin wire, so that the consumption of the thin wire can be reduced. Further, since the molded body 2 cut into the predetermined length is removed from the elevator 10 together with the jig 3, there is no risk of deformation when the molded body is carried out to the next step, and the transportation can be performed efficiently.

[0021]

As described above, according to the present invention, only the load of a predetermined value or less is applied to the molded body portion directly below the die of the molding machine, even though its own weight increases in accordance with the extrusion length. Therefore, it is possible to prevent deformation such as necking and buckling. Also, when cutting, the supporting force at the time of molding is changed to the supporting force desired for cutting, so you can cut sharply,
It is possible to prevent the molded body from being deformed. Further, the molded body is not deformed when it is sent to the next step.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example for carrying out the vertical pressing method of the present invention.

FIG. 2 is a schematic diagram showing an elevator of a molding apparatus according to the present invention.

FIG. 3 is a schematic view showing a cutting unit according to the present invention.

FIG. 4 is a schematic diagram showing a relationship between an elevator and a cutting unit in extrusion molding.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Molding machine, 2 ... Molded body, 3 ... Jig, 10 ... Elevator, 11 ... Straightening table, 12 ... Vertical compliance means, 13 ... Cradle, 20 ... Cutting machine, 26
... thin wire, 30 ... cutting unit, 31 ... U-shaped flange, 36 ... tension applying means, 37 ... pulley

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Isamu Kariya             6010 Mikajiri, Kumagaya City, Saitama Prefecture Hitachi Metals Co., Ltd.             Inside the production system research institute F-term (reference) 4G054 AA05 AB09 BD28                 4G055 AA08 AB03 AC10 BB03 BB08                       BB13

Claims (5)

[Claims] 1. A vertical pressing method in which a molded body is continuously extruded downward and cut when the molded body has a predetermined length, and the lower surface of the molded body is kept until the molded body has the predetermined length. A vertical pressing molding method comprising supporting by a reaction force having a magnitude corresponding to an extruded length of a molded body, and supporting by a reaction force capable of favorably cutting the molded body. 2. A vertical extrusion molding method in which a molded product is continuously extruded downward and cut when the molded product reaches a predetermined length, and the weight of the extruded molded product is calculated based on the extruded length. , The lower surface of the molded body is supported by a reaction force that is controlled to increase according to the extruded weight of the molded body until the molded body reaches the predetermined length, and based on the weight of the molded body when cutting the molded body The vertical pressing molding method is characterized by supporting by a reaction force that is controlled to a set value. 3. The vertical pressing molding method according to claim 1, wherein at the start of cutting the molded body, the molded body is supported by a reaction force such that an incompressible stress acts on the portion to be cut. 4. When a molded product has a predetermined length, a fine wire to which tension is applied is moved in the forward direction to cut the molded product, and when the next molded product has a predetermined length, the thin wire to which the tension is applied is returned. 2. The cutting operation of moving to the next and cutting the molded body is repeated.
Or the vertical pressing method described in 2. 5. A jig, which has a fluid vent hole on the surface and can be moved between processes, is supplied below the molded body, and a reaction force is applied to the lower surface of the molded body extruded through the jig. Then, after the molded body is cut, the molded body is carried out together with the jig.
Or the vertical pressing method described in 2.