JP2008221563A - Extrusion molding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extrusion molding device capable of eliminating a clogging with a molding material, without increasing a pressure between a conveyance means such as a screw and a die. <P>SOLUTION: This extrusion molding device is intended for extruding a molding material from the die 3 and molding it, and comprises a conveyance passage 2 for conveying the molding material, the die 3 arranged in the conveyance passage 2 and a conveyance means 4 for conveying the molding material toward the die 3. In addition, the device is equipped with a rotary member 10 which rotates around the axis parallel to the flow direction of the molding material between the die 3 and the conveyance means 4 and is formed to the shape enabling shearing of the molding material heading for the die 3. The rotary member 10 rotates in the way that the molding material can be sheared in the direction crossing its transfer direction to suppress the setting of the molding material, thereby preventing the hole of the die 3 from being clogged with the molding material. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an extrusion molding apparatus. More specifically, the present invention relates to an extrusion molding apparatus used for forming a powder raw material into a molded body having a predetermined cross-sectional shape.

  Conventionally, powder raw materials are pretreated by adding water, heating, etc. to impart fluidity, and then molding by pressing the fluidized material (hereinafter referred to as molding material) and extruding it from the die hole. To be done. For such a molding operation, an extrusion molding machine is used, and various molding machines have been developed.

  As an example of the extrusion molding machine, there is a screw type extrusion molding machine. In such a screw-type extrusion molding machine, the molding material is supplied to the screw portion in the barrel, and the screw is rotated to compress the molding material in the axial direction of the screw while compressing and compressing the molding material. Then, a molding material can be shape | molded and discharged | emitted from the hole of the die | dye arrange | positioned at the edge part of the screw axial direction in a barrel.

  By the way, clogging of the molding material may occur in the hole of the die. In order to prevent this clogging, the pushing force is increased, and a pushing blade is provided at the screw tip as a member for increasing the pushing force (for example, Patent Document 1).

  By providing these extrusion blades, the force for extruding the molding material from the die becomes strong, but when the extrusion force becomes strong, the pressure between the die and the extrusion blade becomes high, the molding material is strongly compressed, and conversely, There is a possibility that clogging is likely to occur.

JP 2000-6139 A

  In view of the above circumstances, an object of the present invention is to provide an extrusion molding apparatus capable of suppressing clogging of a molding material without increasing the pressure between a conveying means such as a screw and a die.

An extrusion molding apparatus according to a first aspect of the present invention is an apparatus for conveying a molding material by a conveying means and extruding the molding material from the die, and molding the molding material between the die and the conveying means. A rotating member that rotates about a parallel axis is provided, and the rotating member is formed into a shape capable of shearing the molding material directed to the die.
The extrusion molding apparatus according to a second aspect is characterized in that, in the first aspect, the molding material is mainly composed of inorganic powder.
The extrusion molding apparatus according to a third aspect is characterized in that, in the first aspect, the rotating member has a strength capable of maintaining its shape when the rotating member rotates in the molding material.

According to the first invention, since the rotating member rotates so as to shear the molding material from the direction intersecting the moving direction of the molding material, it is possible to suppress the solidification of the molding material, and the molding material becomes the hole of the die. Can prevent clogging.
According to the second invention, even an inorganic powder that tends to harden can be formed into a predetermined shape without causing clogging.
According to the third invention, since the rotating member is not deformed, the rotating member can be rotated so as to shear the molding material positioned between the conveying means and the die.

Next, an embodiment of the present invention will be described with reference to the drawings.
The extrusion molding apparatus of the present invention performs pretreatment such as hydration and heating on a powder raw material to impart fluidity, and pressurizes a material imparted with fluidity (hereinafter referred to as molding material) by a conveying means. An apparatus for producing a molded product by conveying and extruding from a die, characterized in that a rotating member is provided between the die and the conveying means.
In the following examples, the case where the conveying means is a screw type will be described as a representative, but the conveying method (extrusion mechanism) of the molding material is not particularly limited as long as the rotating member of the present invention can be adopted.

  As described above, the extrusion molding apparatus of the present invention is characterized in that a rotating member is provided. First, an outline of the extrusion molding apparatus of the present invention will be described.

  FIG. 1 is a schematic explanatory view of an extrusion molding apparatus 1 according to this embodiment. In the same figure, the code | symbol 2 has shown conveyance paths, such as a screw case. A hollow cylindrical space is formed in the transport passage 2, and a die 3 is provided at one end (left end in FIG. 1A) in the axial direction of the transport passage 2.

As shown in FIG. 1B, a plurality of die holes are formed in the die 3 side by side on a plurality of concentric circles. The plurality of die holes are formed so that the circumferential positions of the holes provided on the adjacent circles are shifted. If FIG. 1 (B), the holes each other located on C ₁ and C _2, and the circumferential position of the holes with each other located on C ₂ and C ₃ are formed as shifted. That is, the plurality of holes are formed in a staggered arrangement.
Needless to say, the positions and the number of the die holes are not limited to the above-described configuration and the configuration shown in FIG.

As shown in FIG. 1, the straight screw 4a of the transport means 4 is disposed in the space in the transport passage 2 so that the central axis thereof coincides with the central axis of the space in the transport passage 2a. The base end of the straight screw 4a is connected to a drive source 4b such as a motor via a speed reducer 4c.
In addition, although the rotation member 10 is provided in the front-end | tip of the straight screw 4a, the detail is mentioned later.

  In addition, a hopper 2 a for supplying a molding material into the conveyance path 2 is connected to the conveyance path 2, and a space inside the hopper 2 a and a space in the conveyance path 2 are communicated with each other.

Since it is a structure as mentioned above, if the molding material which has fluidity | liquidity is supplied in the conveyance path 2 through the hopper 2a, and the drive source 4b of the conveyance means 4 is operated, the straight screw 4a will rotate and a molding material will become It is conveyed toward the die 3 while being pressurized.
Then, since the molding material is molded in the same cross section as the hole of the die 3 and is discharged from the surface of the die 3 (the left side surface in FIG. 1A), a molded body having a predetermined cross-sectional shape is formed. Can do.

  In the above-described example, the case where the molding material is supplied into the conveyance path 2 through the hopper 2a has been described. However, the method for supplying the molding material into the conveyance path 2 is not particularly limited.

  Further, if the molding material discharged from the surface of the die 3 by a predetermined length is cut along a direction parallel to the surface of the die 3 by a cutting means, a granular material having a predetermined length and a predetermined cross-sectional shape. Can also be manufactured. When the molding material has a low viscosity, the molding material may be cut by its own weight when the molding material is discharged from the surface of the die 3 by a predetermined length. In such a case, it is possible to form the granular material without providing a cutting means.

Next, the rotating member 10 will be described.
As shown in FIG. 1, the rotating member 10 is provided at the tip of the straight screw 4 a and is disposed between the tip of the straight screw 4 a and the die 3, that is, between the conveying means 4 and the die 3. Yes.

As shown in FIG. 2, the rotating member 10 is a member formed of, for example, stainless steel, and includes a rotating shaft 11 and a plurality of arm-shaped portions 12.
Note that the material of the rotating member 10 may be any of the above materials as long as the shape does not change due to the resistance applied from the molding material when the rotating member 10 rotates and the strength is sufficient to maintain the shape. It is not limited. In addition, when the molding material contains a corrosive substance, a material that does not deteriorate or corrode when contacted with the molding material is preferable.

  The rotation shaft 11 of the rotation member 10 has a proximal end fixed to the distal end of the straight screw 4a so that the central axis is coaxial with the central axis of the straight screw 4a. In other words, the rotating shaft 11 is fixed to the tip of the straight screw 4 a so that the central axis thereof is coaxial with the central axis of the transport passage 2.

On the other hand, a plurality of arm portions 12 are provided at the tip of the rotating shaft 11. Each arm-shaped part 12 is a rod-shaped member formed in a substantially circular cross section. The base end of each arm-like portion 12 is connected to the outer peripheral surface of the rotary shaft 11 so that the central axis thereof is orthogonal to the central axis of the rotary shaft 11. Further, the plurality of arm portions 12 are arranged at positions that are rotationally symmetric about the rotation shaft 11.
The plurality of arm-like portions 12 are connected to the distal end of the rotating shaft 11 so as to be separated from the distal end of the straight screw 4a when the proximal end of the rotating shaft 11 is fixed to the distal end of the straight screw 4a. That is, when the rotating member 10 is attached to the tip of the straight screw 4a, the plurality of arm portions 12 of the rotating member 10 are between the inner surface of the die 3 (the right surface in FIG. 1) and the tip of the straight screw 4a. Thus, it is disposed at a position away from both.

  Since it is the above structures, when the straight screw 4a rotates, the rotating member 10 will also rotate with the straight screw 4a. At this time, since the rotating shaft 11 of the rotating member 10 is coaxial with the central axis of the straight screw 4a, the arm-like portion 12 of the rotating member 10 is around the central axis of the rotating shaft 11, that is, around the central axis of the transport passage 2. Rotate to.

  Here, between the straight screw 4 a and the die 3, the molding material that has been conveyed under pressure flows parallel to the central axis in the conveyance path 2. That is, the molding material flows in a direction parallel to the central axis of the rotating shaft 11 of the rotating member 10.

  Each arm-shaped portion 12 of the rotating member 10 is disposed between the inner surface of the die 3 (the right-side surface in FIG. 1) and the tip of the straight screw 4a and at a position spaced apart from both of them. When 10 rotates, each arm-shaped part 12 of the rotating member 10 rotates so that a molding material may be sheared from the direction crossing the moving direction. Then, solidification of the molding material located between the inner surface of the die 3 and the tip of the straight screw 4 a can be suppressed, and the molding material can be prevented from clogging into the die hole of the die 3.

Moreover, the arm-shaped part 12 has moved to the direction orthogonal to the flow direction of a molding material. In other words, the arm-like portion 12 moves substantially parallel to the inner surface of the die 3. The cross-section of the arm portion 12 is substantially circular, and the area of the surface that rotates while being inclined with respect to the central axis and rotation direction of the rotating member 10 is small. For this reason, almost no force is applied from the arm-shaped portion 12 to the molding material in the flow direction of the molding material.
Then, since only the pressure conveyance force resulting from rotation of the straight screw 4a is applied to the molding material positioned between the tip of the straight screw 4a and the die 3, the force for extruding the molding material becomes higher than necessary. It is also possible to prevent clogging due to an increase in force for pressing the molding material.

In particular, in the case of a molding material whose main material is a material that tends to solidify, such as ceramics such as alumina, titania and silica, and other inorganic materials, the rotating member 10 functions effectively to prevent the molding material from solidifying.
Therefore, the extrusion molding apparatus 1 of the present embodiment can prevent the molding material from solidifying in the hole of the die 3 or between the die 3 and the straight screw 4a even when extruding the molding material that tends to harden. Clogging of the die hole can be prevented.

  In addition, the arm-shaped part 12 should just be formed so that a molding material can be sheared from the direction which cross | intersects the moving direction, when the rotation member 10 rotates. Further, the cross section of the arm portion 12 is not limited to a circular cross section, and the central axis of the arm portion 12 does not necessarily have to be orthogonal to the central axis of the rotation shaft 11. And if the arm-shaped part 12 is provided so that the area of the surface which rotates in the state inclined with respect to the central axis and rotation direction of the rotating member 10 becomes small, the force which extrudes a molding material is higher than necessary. Can also be prevented.

Further, FIG. 2 shows a case where four arm-shaped portions 12 are provided, but the number of arm-shaped portions 12 may be three or less, or five or more.
Furthermore, the length of the arm-shaped portion 12 is not particularly limited, but the maximum length L (see FIG. 2) is preferably about 8/10 of the radius D1 of the space of the conveyance path 2. With such a length, since the arm-shaped portion 12 passes through most of the cross section of the transport passage 12, local solidification can be effectively prevented.
Furthermore, the plurality of arm-shaped portions 12 do not have to be provided at a rotationally symmetric position, but if provided at a rotationally symmetric position, when the rotary member 10 rotates, the rotary shaft 11 is rotated. There is an advantage that it is possible to suppress the application of a biased force in the direction intersecting the central axis.

  Moreover, the rotation member should just be formed in the shape which can shear the molding material which moves toward the die | dye 3 when it rotates, for example, is good also as a shape as shown in FIG.

FIG. 3 is a schematic explanatory view of another rotating member 15. As shown in FIG. 3, the other rotating member 15 includes a plate-like member 17 at the tip of the rotating shaft 16. The front end portion of the plate-like member 17 is separated on both sides with respect to the surface including the central axis of the rotating shaft 16, and a pair of bent portions 17A and 17B are formed.
The pair of bent portions 17A and 17B are bent in directions opposite to each other such that the surfaces (17a and 17b in FIG. 1) are curved surfaces. Each of the pair of bent portions 17A and 17B is bent to such an extent that the front surfaces 17a and 17b are orthogonal to the surface of the plate member 17 that is not bent. In other words, when the rotating member 15 is attached to the straight screw 4a, the tip surfaces 17a and 17b of the pair of bent portions 17A and 17B are substantially parallel to the surface of the die 3.

  Since the structure is as described above, if the rotating member 15 rotates, the plate-like member 17 rotates so as to shear the molding material from the direction intersecting the moving direction, so that the inner surface of the die 3 and the straight screw 4a Solidification of the molding material located between the tip and the tip can be suppressed, and the molding material can be prevented from clogging into the die hole of the die 3.

  Further, the pair of bent portions 17A and 17B has a rotation center axis and a surface that rotates in a state inclined with respect to the rotation direction in the vicinity of the rotation center axis, and its area is also small. Then, when the rotating member 15 rotates, the force for pressing the molding material in the flow direction is hardly generated, or even if the force for pressing the molding material in the flow direction is generated, the force is very weak. It can be. Accordingly, it is possible to prevent the force for extruding the molding material from becoming higher than necessary, and to prevent clogging due to an increase in the force for pressing the molding material.

  In order to reduce the force with which the plate-like member 17 pushes the molding material when the rotating member 15 rotates, the rotating surface of the rotating member 15 is inclined with respect to the central axis of rotation and the rotation direction. There is no particular limitation on the curvature of the bent portion of the pair of bent portions 17A and 17B and the shape of the plate-like member 17 and the pair of bent portions 17A and 17B. And the plate-like member 17 does not need to provide a pair of bending parts 17A and 17B at the front-end | tip part.

The state of occurrence of die clogging when an inorganic material was molded by the extrusion molding apparatus of the present invention was confirmed.
In the experiment, a molding material kneaded with a kneader (Miyazaki Tekko Co., Ltd., MP-30) was extruded at a speed of 1 mm / min with a strength tester (Minbia, TCM-1000) (see FIG. 4). A cylindrical molded body having a diameter of 1.5 mm was formed by extruding from a die, and the number of clogged holes 10 minutes after the start of extrusion was counted. As shown in FIG. 4, this apparatus is configured to pressurize the molding material with a piston. In addition, the extrusion speed mentioned above is the descending speed of the piston of FIG.

In this embodiment, as shown in FIG. 4, the experimental machine is provided with a rotating member having the same shape as the rotating member of FIG. This rotating member is arranged so that the distance DL between its tip and the inner surface of the die is 1.5 mm. The rotating member used was formed so that the diameter of the rotating shaft was 6 mm, L in FIG. 3 was 30 mm, H was 15 mm, and W was 5 mm, and the rotating speed of the rotating member was 30 r / min.
In the comparative example, the experiment was performed without providing the rotating member.

The die has a die inlet inner diameter DDI of 40 mm and an outlet inner diameter DDO of 31.53 mm, and the outlet side surface has 10 holes of 1.5 mm diameter at equal intervals at a position 22.7 mm from the center. .
The composition of the molding material was Al ₂ O 3: 67 parts by weight, TiO ₂ : 33 parts by weight, binder 15 parts by weight, and water 20.8 parts by weight. A water-soluble polymer compound was used as the binder.

  In this experiment, in order to shorten the experiment time, the molding material extruded from the die is dried by applying a wind at a drying temperature of 150 ° C. and a wind speed of 3.7 m / sec from a dryer.

As a result of the experiment, in the example in which the rotating member was provided, the clogging of the die did not occur even after 10 minutes from the start of extrusion, whereas in the comparative example, five holes were formed after 10 minutes from the start of extrusion. Clogging occurred.
From the above, it can be confirmed that the provision of the rotating member of the present invention is effective in preventing clogging of dies.

  The extrusion molding apparatus of the present invention is suitable for molding a material that is easily solidified, such as ceramics such as alumina, titania and silica, and other inorganic materials.

It is a schematic explanatory drawing of the extrusion molding apparatus 1 of this embodiment. 2 is a schematic explanatory diagram of a rotating member 10. FIG. FIG. 6 is a schematic explanatory diagram of another rotating member 15. It is a schematic explanatory drawing of the experimental apparatus of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Extrusion molding apparatus 2 Conveyance path 3 Dies 4 Conveying means 10 Rotating member 15 Rotating member

Claims (3)

An apparatus comprising a conveyance path for conveying a molding material, a die provided in the conveyance path, and a conveyance means for conveying the molding material toward the die, and extruding the molding material from the die,
Between the die and the conveying means, a rotating member that rotates about an axis parallel to the flow direction of the molding material is provided,
The rotary member is formed in a shape capable of shearing a molding material directed to the die. The extrusion molding apparatus according to claim 1, wherein the molding material is an inorganic powder as a main material. The rotating member is
2. The extrusion molding apparatus according to claim 1, wherein the rotating member has a strength capable of maintaining its shape when rotated in the molding material.

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