JP2008155442A - Screw extruder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a screw extruder for obtaining a rod-shaped molding reduced in density irregularity using an extrusion dividing member having a simple structure without using a cylindrical straightening part. <P>SOLUTION: In the screw extruder 1, the extrusion dividing member 9 larger than the outlet part 8a of a mold 8 is arranged on the line, which connects the screw leading end part 7a and the outlet part 8a of the mold 8 so as not only to extrude and divide the flow of a molding material but also to cover the outlet part 8a when looked from the screw leading end part 7a. By this constitution, the rod-shaped molding reduced in density irregularity, reduced in the occurrence of internal voids and reduced in the occurrence of deformation or cracking at the time of drying and baking can be efficiently manufactured at a low cost. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a screw-type extruder for obtaining a rod-shaped molded body.

  Conventionally, an extrusion molding method has been used as a molding method for obtaining a rod-shaped molded body. The extrusion molding machine used for this extrusion molding method continuously forms a rod-shaped molded body having a specific outlet shape in cross-sectional shape by extruding a molding material prepared in a clay shape from a mold having a specific outlet shape. And can be suitably used for efficient mass production of rod-shaped molded bodies.

  This extrusion molding machine includes a plunger type and a screw type, but the screw type is superior in that it can be continuously formed and has excellent mass productivity as compared with the plunger type in which the supply of molding material is a batch type. Extruders are commonly used.

  FIG. 5 is a schematic cross-sectional view showing an example of a conventional screw-type extruder for obtaining a rod-shaped molded body.

  The screw-type extruder 20 shown in FIG. 5 has a vacuum chamber 25 between an upper screw 24 and a lower screw 27. The upper screw 24 covers the upper barrel 23 and the lower screw 27 covers the lower barrel 26, respectively. It has been broken. Also, a molding material inlet 22 is opened in a part of the upper barrel 23, and a mold 28 is connected to the outlet side of the lower barrel 26.

  Furthermore, the upper stage screw 24 and the lower stage screw 27 are formed with a spiral convex portion 31, one of which is connected and fixed to the upper stage bearing 29 and the lower stage bearing 30, respectively, and is connected to a power source (not shown). The vacuum chamber 25 is connected to a vacuum pump (not shown) for evacuating the inside of the vacuum chamber 25.

  Next, a procedure for forming a rod-shaped molded body using the screw type extruder 20 will be described.

  First, for example, flour and water, or ceramic powder, a binder and water are mixed and kneaded to obtain a clay-like molding material. Then, this molding material is introduced from the inlet 22 of the extrusion molding machine 20. The charged molding material is pushed out to the vacuum chamber 25 through the gap between the upper screw 24 and the upper barrel portion 23 by the rotation of the upper screw 24. The molding material extruded into the vacuum chamber 25 is decompressed by a vacuum pump connected to the vacuum chamber 25 and discharges bubbles inside the molding material. After that, by rotating the lower screw 27, it is pushed out through the gap between the lower screw 27 and the lower barrel 26 in the direction of the mold 28, and passes through the outlet portion 28a of the mold 28, thereby corresponding to the outlet shape. A rod-shaped molded body having a specific cross-sectional shape is obtained.

  The rod-shaped molded body thus obtained is, for example, a rod-shaped noodle product when a molding material using flour and water is used. Moreover, when it is set as the molding material using ceramic powder, a binder, and water, it becomes a rod-shaped ceramic member by drying and baking the obtained molded object.

  However, according to the screw-type extrusion molding machine 20, it is possible to continuously form a rod-shaped molded body, but the obtained rod-shaped molded body has a problem that the variation in density in the cross section is large.

  That is, in the screw type extrusion molding machine 20, the extrusion pressure applied to the molding material is applied by the shearing action by the spiral convex portion 31 provided on the outer peripheral part of the lower screw 27. The extrusion pressure varies depending on the location, and the low-density part is the central part of the molding material (hereinafter simply referred to as “connecting the screw tip part 27a on the extension of the axis of the lower screw 27) and the outlet part 28a of the mold 28” A phenomenon that makes it easier to concentrate on the center part) occurs. For this reason, density variation occurs inside the obtained rod-shaped molded body, the density of the central portion becomes extremely low, creating a cavity inside, and deformation or cracking occurs when the rod-shaped molded body is dried or fired. There was a problem that it occurred.

In order to solve this problem, Patent Document 1 includes a cylindrical rectifying unit for adjusting the flow of the molding material between the lower screw 27 and the mold 28, and a plurality of connecting an inlet and an outlet in the rectifying unit. A flow path is formed to divide the flow of the molding material, and the molding material flowing into the central portion at the inlet of the rectifying unit is at the peripheral portion at the outlet of the rectifying portion, and the molding material flowing into the peripheral portion at the inlet of the rectifying portion is at the outlet of the rectifying portion. Disclosed are extrusion machines that are each modified in the center. According to this extrusion molding machine, since the molding material can be mixed without difficulty in the barrel, the density variation is alleviated, and a molded body having high strength, bending, warping, and occurrence of cracks inside is obtained.
Japanese Unexamined Patent Publication No. 2006-103072

  However, since the resistance to the flow of the molding material in the cylindrical rectifying unit becomes extremely large, the extruder disclosed in Patent Document 1 cannot be used in a small-sized extruder with a small extrusion pressure.

  Further, in the cylindrical rectifying unit, the molding material is completely separated into a plurality of flow paths, so that the molding material separated even at the rear of the cylindrical rectifying unit cannot be completely integrated and obtained. There was a problem that linear flaws occurred on the surface of the molded body.

  Further, since the structure of the cylindrical rectifying unit is complicated, there are problems that the production cost of the extrusion molding machine is increased, the maintenance is difficult, and the efficiency of the molding operation is deteriorated.

  The present invention has been devised to solve the above-described problems, and uses a pushing member having a simple structure without using a cylindrical rectifying unit, and a screw type for obtaining a rod-shaped molded body with less density variation. It is an object of the present invention to provide an extrusion molding machine.

  The screw-type extrusion molding machine of the present invention has a pushing member larger than the outlet portion seen from the screw tip portion so as to push the flow of the molding material on the line connecting the screw tip portion and the die outlet portion. And is arranged so as to cover the outlet portion.

  Moreover, the screw-type extrusion molding machine of the present invention is characterized in that, in the above-described configuration, a plurality of the separating members are arranged at different positions on the line.

  Furthermore, the screw type extrusion molding machine according to the present invention has the above-described configuration, wherein the plurality of separation members each have a support leg toward the inner wall of the molding machine, and the support leg is viewed from the tip of the screw. It is characterized by being arranged at equal intervals in the circumferential direction.

  According to the screw type extrusion molding machine of the present invention, the pushing member larger than the outlet portion is seen from the screw tip portion so as to push the flow of the molding material on the line connecting the screw tip portion and the die outlet portion. The low density part of the central part of the molding material that connects the screw tip and the outlet part of the mold on the extension line of the screw shaft center is once centered by the pushing member. Since the concentration of the low density portion in the central portion is alleviated by being distributed so as to be pushed away from the portion in the outer peripheral direction, the obtained molded body has a small variation in density and few cavities are generated inside, and In addition, deformation and cracks are reduced when the rod-shaped molded body is dried and fired. Furthermore, since the structure of the extrusion molding machine is simple and the number of parts is small, the production cost of the screw type extrusion molding machine is kept low, maintenance is easy, and molding efficiency is improved.

  In addition, since the resistance when the molding material passes through the pressing member is small, it is possible to obtain a rod-shaped molded body with little variation in density even when used in a small extrusion molding machine having a small extrusion pressure.

  Further, according to the screw type extrusion molding machine of the present invention, when a plurality of separating members are arranged at different positions on the line connecting the screw tip portion and the outlet portion of the mold, the screw on the extension line of the screw tip portion Since the low density portion of the central portion of the molding material connecting the tip portion and the outlet portion of the mold can be more effectively dispersed by a plurality of pushing members, a rod-shaped molded body with less variation in density is obtained. It becomes possible.

  Furthermore, according to the screw type extrusion molding machine of the present invention, each of the plurality of separation members has a support leg toward the inner wall of the molding machine, and the like in the circumferential direction when the support leg is viewed from the screw tip. When arranged at intervals, the resistance when the molding material passes through the support legs is made uniform in the circumferential direction, so that density variation is more effectively eliminated, and rod-shaped molding with less deformation and cracking during drying The body can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 shows an example of an embodiment of a screw-type extruder according to the present invention, (a) is a schematic cross-sectional view, and (b) shows a mold from the screw tip side of the lower screw in (a). It is sectional drawing which looked at the exit part.

  The screw-type extruder 1 has a vacuum chamber 5 between an upper screw 4 and a lower screw 7, and the upper screw 4 is covered with an upper barrel 3 and the lower screw 7 is covered with a lower barrel 6. Further, a molding material inlet 2 is opened in a part of the upper barrel 3, and a mold 8 is connected to the outlet side of the lower barrel 6. Here, the screw-type extrusion molding machine 1 refers to an apparatus in which the extrusion molding machine and the mold 8 are combined.

  Furthermore, the upper stage screw 4 and the lower stage screw 7 are formed with a spiral convex portion 12, one of which is connected and fixed to the upper stage bearing 10 and the lower stage bearing 11 and connected to a power source (not shown). The vacuum chamber 5 is connected to a vacuum pump (not shown) for evacuating the inside of the vacuum chamber 5.

  Next, a procedure for forming, for example, a ceramic rod-shaped molded body using the screw-type extruder 1 will be described.

  First, ceramic powder, a binder, and water are mixed with a mixing and stirring mixer, and further passed through a three-roll kneader three times to knead to obtain a clay-like molding material. Then, this molding material is charged from the charging port 2 of the screw type extrusion molding machine 1. The input molding material is pushed out to the vacuum chamber 5 through the gap between the upper screw 4 and the upper barrel 3 while being sheared by the convex portion 12 by the rotation of the upper screw 4. The molding material extruded into the vacuum chamber 5 is decompressed by a vacuum pump connected to the vacuum chamber 5 to discharge bubbles inside the molding material, and then sheared to the convex portion 12 by the rotation of the lower screw 7. However, it is pushed out in the direction of the mold 8 through the gap between the lower screw 7 and the lower barrel 6, and passes through the outlet 8 a of the mold 8, thereby forming a rod-shaped molded body.

  When extrusion is performed using such a screw-type extrusion molding machine 1, the extrusion pressure applied to the molding material is applied by a shearing action by the spiral convex portion 12 provided on the outer peripheral portion of the lower screw 7. However, the extrusion pressure due to this shearing action varies, and the low-density portion of the extruded molding material has a screw tip 7 a on the extension of the axis of the lower screw 7 and an outlet 8 a of the mold 8. Phenomenon that concentrates in the center of the molding material.

  If the density of the central portion is low, there arises a problem that cracks and deformation occur in the rod-shaped molded body due to variations in shrinkage during drying and firing. In addition, since the density of the central portion becomes extremely low, a hollow defect is formed at the time of molding, or the central portion is not densified at the time of firing, resulting in a defect.

  Therefore, the present inventor has made various studies so as to obtain a rod-shaped molded body with less variation in density, and as a result, as shown in FIG. Screw-type extrusion in which a pressing member 9 larger than the outlet portion 8a of the mold 8 is arranged so as to cover the outlet portion 8a of the mold 8 when viewed from the screw tip portion 7a side so as to push the flow of the molding material. It has been found that the molding machine 1 can provide a rod-shaped molded body in which no voids are formed in the molded rod-shaped molded body, and no deformation or cracking occurs during drying or firing.

  This is because the low-density portion concentrated in the central portion of the molding material is once dispersed from the central portion toward the outer peripheral direction by the pushing member 9 and then extruded toward the outlet portion 8a of the mold 8. By being pressure-filled again, the variation in density between the central portion and the peripheral portion is reduced, and then passes through the outlet portion 8a of the mold 8 to become a rod-shaped molded body. There is little variation in density between the central part and the outer peripheral part, no cavities are formed in the molded rod-shaped molded body, and no deformation or cracking occurs during drying or firing.

  Here, the pushing member 9 is disposed so as to cover the outlet portion 8a of the mold 8 when viewed from the screw tip portion 7a side, so that the outlet portion 8a of the die 8 is completely viewed from the screw tip portion 7a side. If not covered, the low density portion concentrated in the central portion of the molding material is not completely dispersed in the outer peripheral direction by the pushing member 9, and a part passes through the outlet portion 8 a of the mold 8 as it is. Therefore, the obtained rod-shaped molded body has a large variation in density between the central portion and the outer peripheral portion, a cavity is formed inside the molded rod-shaped molded body, and deformation or deformation occurs during drying or firing. This is because cracks occur.

  Accordingly, the pushing member 9 larger than the outlet portion 8a of the mold 8 is seen from the screw tip portion 7a side so as to push the flow of the molding material on the line connecting the screw tip portion 7a and the outlet portion 8a of the die 8. If the screw-type extruder 1 disposed so as to cover the outlet 8a of the mold 8 is used, there is no cavity inside the molded rod-shaped body, and deformation and cracks occur during drying and firing. Since a rod-shaped molded body can be provided, the screw-type extrusion molding machine 1 can be provided with a simple structure of the extrusion molding machine, low cost and easy maintenance. Moreover, the obtained rod-shaped molded body is excellent in mass productivity and low in cost.

  There are various types of screw-type extrusion molding machines, which may be appropriately selected according to the size of the desired molded body, but considering the mass productivity and maintainability, the diameter of the lower screw 7 is 30 mm to About 200 mm is suitable.

  The pushing member 9 is preferably arranged in a size so as to cover the outlet portion 8 a of the mold 8, and the pushing member 9 is perpendicular to the line connecting the screw tip portion 7 a and the outlet portion 8 a of the die 8. Is preferably up to 50% of the cross-sectional area in the axial direction of the lower screw 7, and if it exceeds 50%, the flow of the molding material is hindered.

  Moreover, the screw type extrusion molding machine 1 of the present invention is an enlarged cross-sectional view of the vicinity of the screw tip portion in FIG. 2 (a), and an enlarged view when the outlet portion of the mold is viewed from the screw tip portion. As shown in the sectional view, a plurality of pressing members 9 a and 9 b are arranged at different positions of the mold 8 on the line connecting the screw tip 7 a and the outlet 8 a of the mold 8.

  By doing so, the low density portion concentrated in the central portion of the molding material is more effectively dispersed from the central portion toward the outer peripheral direction by the plurality of pushing members 9a and 9b. The variation in density is further reduced, there are fewer cavities inside the molded rod-shaped molded body, and deformation and cracks are less likely to occur during drying and firing.

  Further, in the screw type extrusion molding machine 1 of the present invention, as shown in an enlarged sectional view similar to FIG. 2 (b) in FIG. The support legs are arranged at equal intervals in the circumferential direction as viewed from the screw tip 8a.

  By doing so, the resistance when the molding material passes through the support leg is made uniform in the circumferential direction, so that the obtained rod-shaped molded body has less variation in density, and the molded rod-shaped molded body is dried. Less deformation and cracks occur at the time.

  Next, as a method for manufacturing this rod-shaped molded body, if the molding material is, for example, a mixture of wheat flour and water to form a molding material, the obtained rod-shaped molded body has a necessary water content. Drying to a stick-shaped dry noodle product such as udon or spaghetti, and since there is little variation in density, it is unlikely to be deformed or broken during drying, and a low-cost dry noodle product with excellent yield is produced. can do.

  Further, if a thermosetting resin is used as a molding material, the obtained rod-shaped molded body is subjected to a heat treatment necessary for the resin to be cured, and as a rod-shaped resin member, for example, for an electronic device. It can be used as an insulating member.

  Further, as a manufacturing method for obtaining a rod-shaped ceramic member, a molding material is prepared by mixing ceramic powder, a binder, and additives such as water, a plasticizer, and a dispersant, and the molding material is used as a screw type of the present invention. The extrusion molding machine 1 is used to extrude from the mold 8 to form a rod-shaped molded body, and the obtained rod-shaped molded body is dried and fired in an appropriate firing furnace.

  In this case, as the ceramic powder, alumina, zirconia, silicon nitride, silicon carbide, aluminum nitride, ferrite, cordierite, etc. are appropriately selected according to the purpose of use, and silicon oxide, calcium oxide, magnesium oxide are used as necessary. Sintering aids such as nickel oxide, zinc oxide and copper oxide may be added. In addition, as a binder, considering the flowability at the time of extrusion molding, the shape retention of the molded body, the strength of the molded body, and the handling property, it is preferable to use a cellulose-related binder, and in particular, water-soluble cellulose. It is preferred to use ether.

  The molding material inside the screw-type extruder 1 is subjected to frictional heat because it receives shearing forces generated between the upper screw 4 and the upper barrel 3 and between the lower screw 7 and the lower barrel 6. The temperature rises. Depending on the molding material, the fluidity deteriorates or the characteristics deteriorate due to the temperature rise due to this frictional heat. Therefore, the barrel portion and the screw interior of the screw-type extruder 1 can be cooled with cooling water. It is preferable to do.

The molding procedure for obtaining the rod-shaped ceramic member by the screw-type extruder 1 of the present invention is as follows. First, the ceramic powder, the binder, and water are mixed with a mixing and stirring mixer, and further mixed into a three-roll kneader. Knead and knead to obtain a clay-like molding material. At this time, the clay-shaped molding material after kneading is, for example, a flow tester CFT-500C type manufactured by Shimadzu Corporation. Setting conditions of pressure 6 MPa, temperature 20 ° C., die diameter 1 mm, and die length 1 mm It is good to adjust so that the measured value in may become a viscosity range of 1 × 10 ² to 1 × 10 ⁴ Pa · s.

  Then, this molding material is charged from the charging port 2 of the screw type extrusion molding machine 1. The charged molding material is pushed out to the vacuum chamber 5 through the gap between the upper screw 4 and the upper barrel 3 by the rotation of the upper screw 4. The molding material extruded into the vacuum chamber 5 is decompressed by a vacuum pump connected to the vacuum chamber 5 to discharge bubbles inside the molding material, and then the lower screw 7 and the lower barrel are rotated by the rotation of the lower screw 7. The rod-shaped molded body is obtained by being pushed out in the direction of the mold 8 through the gap with 6 and passing through the outlet portion 8 a of the mold 8.

  And this rod-shaped molded object is dried. Rapid drying may be natural drying because it deforms the rod-shaped molded body, but after drying for a certain period of time, in order to further dry the remaining moisture, a drying chamber set at a room temperature of about 80 ° C with a kerosene boiler or the like It is preferable to carry out drying in combination.

  After the rod-shaped body is dried, firing is performed. The firing temperature pattern varies depending on the ceramic powder used. For example, when alumina is used, the temperature is first raised from room temperature to a temperature of 300 to 500 ° C. over 2 to 6 hours, and then 1 to 4 hours. Thus, the binder contained in the rod-shaped molded body is burned out. Thereafter, the temperature is raised to a maximum temperature of 1400 to 1650 ° C. over 2 to 6 hours, a holding time of 1 to 4 hours is provided, and then gradually cooled to room temperature.

  The rod-like ceramic member obtained in this way can be suitably used as an insulating member used for a thermal fuse, a breaker or the like that requires heat resistance and insulation.

  Examples of the screw type extruder 1 of the present invention will be described below.

(Example 1)
A rod-shaped molded body is produced using the screw-type extruder 1 of the present invention shown in FIG. 1 and the conventional screw-type extruder 20 shown in FIG. 5, and the resulting rod-shaped molded body is deformed or cracked, or A comparative test was conducted to confirm whether or not defects such as cavities in the interior caused by density variations would be reduced. At this time, the dimension of the outlet portion 8a of the mold 8 was a circular shape having a diameter of 5 mm.

  First, a molding material for extrusion molding was produced. As a raw material powder to be used, a commercially available alumina raw material having a purity of 99% and an average particle diameter of 1 μm was used. 100 parts by mass of this alumina raw material, 3 parts by mass of sintering aid, 100 parts by mass of alumina raw material, 4 parts by mass of water-soluble cellulose ether as a binder, 6 parts by mass of surfactant, and 8 parts by mass Were mixed in a commercially available mixing and stirring mixer. Next, this was passed through a three-roll kneader three times and kneaded to obtain a clay-like molding material.

  Next, this molding material was thrown in from the inlet 2 of the screw type extrusion molding machine 1 of the present invention shown in FIG. 1 to perform extrusion molding.

  The inside of the upper barrel 3, the lower barrel 6 and the lower screw 7 of the screw type extrusion molding machine 1 has a water cooling jacket structure, and the cooling water set to 10 ° C. or less is circulated to increase the temperature of the molding material. Prevented. Further, the vacuum pump was operated and molding was performed while the vacuum chamber 5 was evacuated.

  In addition, as the molding conditions of the screw-type extruder 1, the rotational speeds of the upper screw 4 and the lower screw 7 were adjusted so that the molding speed of the rod-shaped molded body was 8 to 12 m / min.

  The obtained rod-shaped compact was cut to a length of 10 cm immediately after molding, dried for 12 hours by natural drying, and then placed in a batch-type firing furnace and fired to form a rod-shaped ceramic. A member was obtained. The firing pattern at this time was raised from room temperature to 400 ° C. in the air in 3 hours and then held for 2 hours, then raised to 1600 ° C. in 6 hours and then held for 2 hours, taking 6 hours. The pattern was cooled to room temperature. 100 rod-shaped ceramic members were produced by each molding machine.

  The position for measuring the deformation amount of the obtained rod-shaped ceramic member is shown in FIG.

  The rod-shaped ceramic member 50 is placed on a table (not shown) of a tool microscope, and the rod-shaped ceramic member 50 is confirmed by looking at the rod-shaped ceramic member 50 from an eyepiece having a dimension measurement scale of the tool microscope. It is only necessary to adjust the table so as to match both ends of the plate and measure the deformation amount H at the place where the deformation amount is the maximum. Moreover, the presence or absence of the generation | occurrence | production of a crack was confirmed visually after processing with a penetrant flaw detection liquid. Furthermore, the central part of the length of the rod-shaped ceramic member is cut with a rotary cutting machine equipped with a diamond grindstone, and the cross section is observed with a binocular microscope with a magnification of 30 times to confirm the presence of internal cavities. did.

  As a result, the rod-shaped ceramic member formed using the screw-type extruder 1 of the present invention had a maximum deformation amount H of 1.2 mm, and the number of cracks generated was 3 out of 100. On the other hand, the rod-shaped ceramic member formed by using the conventional screw-type extruder 20 had a large maximum deformation amount H of 2.8 mm, and the number of cracks was as many as 8 out of 100.

  Further, the rod-shaped ceramic member formed by using the screw-type extruder 1 of the present invention had 0 of 100 internal cavities, whereas the conventional screw-type extruder 20 In the rod-shaped ceramic member formed using, the number of internal cavities was as high as 21 out of 100.

  From this, on the line connecting the screw tip 7a and the outlet 8a of the mold 8, the pushing member 9 larger than the outlet 8a of the die 8 is pushed from the screw tip 7a so as to push the flow of the molding material. The rod-shaped molded body obtained by the screw-type extrusion molding machine 1 of the present invention disposed so as to cover the outlet portion 8a of the mold 8 when viewed has little variation in density and has a cavity inside the molded rod-shaped molded body. It was confirmed that the amount of deformation and cracking during drying or firing was small.

(Example 2)
Next, the screw type extrusion molding machine 1 of the present invention shown in FIG. 2 in which the two separating members 9a and 9b are arranged at different positions on the line connecting the screw tip portion 7a and the outlet portion 8a of the mold 8 will be described. Using this, a rod-shaped ceramic member was produced in the same manner as in Example 1, and a test was conducted to confirm whether the obtained rod-shaped ceramic member was deformed, cracked, or has few internal cavities.

  As a result, the maximum amount of deformation H of the obtained rod-shaped ceramic member was 0.8 mm, and the number of cracks generated was 1 out of 100. The number of internal cavities was 0 out of 100.

  From this, a rod-shaped molded body obtained by using the screw-type extrusion molding machine 1 in which a plurality of separation members 9a and 9b are arranged at different positions on the line connecting the screw tip portion 7a and the outlet portion 8a of the mold 8. It was confirmed that there was less variation in density and less deformation and cracks during drying and firing.

(Example 3)
Next, as shown in FIG. 3, the pushing members 9c, 9d and 9e are arranged at three different locations on the line connecting the screw tip 7a and the outlet 8a of the mold 8, and these pushing members 9c, 9d. 9e have support legs facing the inner wall of the screw type extruder 1, and these support legs are arranged at equal intervals of 120 degrees in the circumferential direction when viewed from the screw tip 7a. Using the screw-type extruder 1 of the present invention, a rod-shaped ceramic member was produced in the same manner as in Examples 1 and 2, and the resulting rod-shaped ceramic member would have few deformations, cracks, and internal cavities. A test was conducted to confirm whether or not.

  As a result, the maximum value of the deformation amount H of the obtained rod-shaped ceramic member was 0.4 mm, and the number of cracks generated was 0 out of 100. The number of internal cavities was 0 out of 100.

  Therefore, the plurality of separating members 9c, 9d, and 9e each have a support leg toward the inner wall of the screw-type extrusion molding machine 1, and the support leg is seen in the circumferential direction when viewed from the screw tip 7a. It is confirmed that the rod-shaped molded body obtained by using the screw-type extrusion molding machine 1 of the present invention disposed at intervals is further less uneven in density, and is less deformed and cracked during drying and firing. It was.

  In the above embodiment, the number of the separating members 9 is 1 to 3, but the present invention is not limited to these, and the number can be arbitrary. However, from the viewpoint of manufacturing cost and maintainability of the screw-type extrusion molding machine 1, the number of the separating members 9 is desirably 6 or less.

  Further, in the above embodiment, the pushing member 9 and its supporting leg are both flat, but for example, the flow of the molding material is pushed onto the line connecting the screw tip 7a and the outlet 8a of the mold 8. Thus, if it is the pushing member 9 larger than the exit part 8a of the metal mold | die 8, it is good also as a column shape or a wing | blade shape. In that case, the resistance when the molding material passes is reduced, and a rod-shaped molded body with little variation in density can be obtained even in the small screw-type extrusion molding machine 1 with a small extrusion pressure, which is more preferable.

An example of embodiment of the screw type extrusion molding machine of the present invention is shown, (a) is a schematic sectional view, (b) is an enlarged cross section when looking at the exit part of a mold from the screw tip part in (a). FIG. An example of an embodiment of a screw type extrusion molding machine of the present invention is shown, (a) is an enlarged cross-sectional view of the vicinity of the screw tip, and (b) is a view of the outlet of the mold from the screw tip in (a). FIG. It is an expanded sectional view when the exit part of a metal mold | die is seen from the screw front-end | tip part which shows an example of embodiment of the screw type extrusion molding machine of this invention. It is a figure which shows the position which measures the deformation amount of the rod-shaped ceramic member of this invention. It is a schematic sectional drawing which shows an example of the conventional screw type extrusion molding machine.

Explanation of symbols

1: Extruder 2: Input port 3: Upper barrel 4: Upper screw 5: Vacuum chamber 6: Lower barrel 7: Lower screw 7a: Screw tip 8: Mold 8a: Outlet portions 9, 9a, 9b, 9c, 9d, 9e: Pushing member
10: Upper bearing
11: Lower stage bearing
12: Convex

Claims (3)

In the screw-type extrusion molding machine, on the line connecting the screw tip and the outlet of the mold, a pushing member larger than the outlet so as to push the flow of the molding material is seen from the screw tip. A screw-type extruder, which is arranged so as to cover the part. The screw-type extruder according to claim 1, wherein a plurality of the pushing members are arranged at different positions on the line. 3. The push-separating members each have a support leg toward the inner wall of the molding machine, and the support legs are arranged at equal intervals in the circumferential direction when viewed from the tip of the screw. The screw-type extrusion molding machine as described.

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