JP2012076132A - Method and device for extrusion processing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for extrusion processing, which can manufacture an extruded material having a preferable appearance and a lowered surface roughness.SOLUTION: The method for extrusion processing includes: a billet pressing step of pressing a billet 6 in a container 1 by a stem 2 to make the billet 6 pass through an extrusion die 3 and forming the extruded material 20; a discard thickness reduction step of pressing a discard 7 in a thickness direction thereof by the stem 2, after or while releasing the restraint of an outer periphery of the discard 7 restrained by the container 1 to reduce the thickness of the discard 7; a discard cutting step of cutting the discard 7 after the discard thickness reduction step; and a mold release agent application step of applying a mold release agent 8 that prevents the discard 7 from adhering to a pressing surface 2z to at least one of the pressing surface 2z of the stem 2, on which the stem 2 presses the billet 6, and an upstream end surface 6z of the billet 6 before the billet pressing step.

Description

  The present invention relates to an extrusion method including a step of cutting a billet discard, an extrusion apparatus used in the extrusion method, and a method for manufacturing a photosensitive drum base tube.

  In the present specification, the term “aluminum” is used to include both pure aluminum and an aluminum alloy unless otherwise specified. Further, “upstream” and “downstream” mean upstream and downstream in the extrusion direction, respectively.

  Extruded materials are widely used for photosensitive drum base pipes, OA equipment parts, building materials, exterior materials, and the like. In recent years, quality requirements for the surface properties of extruded materials have become stricter. In particular, the quality requirements for the appearance and surface roughness of the extruded material are particularly severe.

  As an appearance defect and surface roughness defect of an extruded material generated at the time of extrusion, an air entrapping defect is cited. This air entrainment defect is not only a problem with the appearance and surface roughness of the extruded material, but also when the plastic processing such as drawing or bending is performed in the next process, the appearance of the plastic processed product There is a problem of worsening or increasing the surface roughness.

  Further, when the drawing process is performed in the next process, the air entrainment defect is stretched in the drawing direction by the drawing process, and as a result, a problem that the range of the appearance defect and the surface roughness defect becomes large occurs. In particular, when a drawn material that has been drawn is used in a photosensitive drum base tube, a surface roughness defect is stretched in the axial direction of the raw tube, causing a problem that a long linear defect appears in a printed image.

  As a cause of the occurrence of air entrainment failure, the state of the cut surface of the discard is bad. Therefore, the shape of the extrusion die has been improved. For example, Japanese Patent Laid-Open No. 2002-1422 (Patent Document 1) discloses that a recess is provided in the central portion of the upstream end face of an extrusion die (specifically, a porthole die) as an improvement on the shape of the extrusion die. Yes. Furthermore, Japanese Patent Laying-Open No. 2006-26672 (Patent Document 2) discloses that an inner peripheral wall surface of a recess is formed so as to expand in a downstream direction. Note that the discard is also called a press residue, and is a billet remaining in the container after the extrusion process. This discard contains a large amount of impurities.

  Known publications relating to discarding discards include JP-A-5-285532 (Patent Document 3) and JP-A-2003-112220 (Patent Document 4).

Japanese Patent Laid-Open No. 2002-1422 JP 2006-26672 A JP-A-5-285532 JP 2003-112220 A

  By the way, the present inventors have found that the quality of the state of the cut surface of the discard is strongly influenced by the thickness of the discard. That is, as shown in FIG. 9 (a), when the discard 57 present on the upstream side of the upstream end surface 53a of the extrusion die 53 is thick, as shown in FIGS. 9 (b) and 9 (c). In the middle of cutting the discard 57 along the upstream end surface 53a of the extrusion die 53 with the shear blade 54 in order to cut out the card 57, the discard 57 is inserted into the extrusion die 53 (specifically, the port hole of the extrusion die 53). Along with a part 61 of the remaining extruded material remaining on the extrusion die 53, it is scraped off from the extrusion die 53. As a result, a void (recess) x is formed in the extrusion die 53. In this state, when a new billet (not shown) is pressed against the remaining extruded material in the extrusion die 53 and crimped, and the extrusion process is resumed, the air in the void x is caught in the extruded material 70, As a result, the appearance and surface roughness of the extruded material 70 are deteriorated.

  The present invention has been made in view of the above-described technical background, and an object of the present invention is to provide an extrusion method for producing an extruded material having a good appearance and a small surface roughness, and an extrusion apparatus used in the extrusion method. Another object of the present invention is to provide a method of manufacturing a photosensitive drum base tube using the extrusion method.

  The present invention provides the following means.

[1] A billet pressing step in which a billet loaded in a container is pressed by a stem to allow the billet to pass through an extrusion die and form an extruded material;
About the billet discard remaining in the container after the billet pressing step, after releasing or releasing the restraint of the outer peripheral surface of the discard by the container, the discard in the thickness direction A discard thickness reducing step for reducing the thickness of the discard by pressing the stem,
After the discard thickness reducing step, a discard cutting step of cutting the discard with a shear blade;
Before the billet pressing step, a release agent for preventing the discard from adhering to the pressing surface is applied to at least one of the pressing surface of the stem to the billet and the upstream end surface of the billet. A release agent coating process;
An extrusion method comprising the steps of:

  [2] In the release agent application step, the release agent is applied to at least one of the pressing surface and the upstream end surface of the billet so that the application area of the release agent with respect to the area is 50% or more. 2. The extrusion method according to item 1 above.

  [3] The extrusion method according to claim 1 or 2, wherein, in the release agent application step, the release agent is applied to the pressing surface and the upstream end surface of the billet, respectively.

[4] After the discard cutting step, a new billet pushing step of pressing a new billet loaded in the container against the remaining extruded material in the extrusion die,
After the new billet splicing process, an extrusion process restarting process for restarting the extrusion process,
The extrusion method according to any one of the preceding items 1 to 3, comprising:

[5] The extrusion method is an aluminum alloy extrusion method,
The extrusion method according to any one of the preceding items 1 to 4, wherein a temperature of the discard in the discard thinning step is in a range of 400 to 520 ° C.

  [6] A method for producing a base tube for a photosensitive drum substrate, wherein the extrusion tube obtained by the extrusion method is drawn after the extrusion method according to any one of 1 to 5 above.

[7] Container,
A stem for pressing the billet loaded in the container;
A shear blade for cutting out the billet discard;
A release agent applying means for applying a release agent for preventing the discard from adhering to the pressing surface on at least one of the pressing surface of the stem to the billet and the upstream end surface of the billet; Equipped,
The stem is further configured to press the discard in the thickness direction so that the thickness decreases after or after the restraint of the outer peripheral surface of the discard by the container is released. An extrusion apparatus characterized by that.

  The present invention has the following effects.

  According to the extrusion method of the preceding item [1], the discard is easily curled when the discard is cut by reducing the thickness of the discard in the discard thinning step. Then, by discarding the discard in the discard cutting step, the discard does not fall off together with a part of the remaining extruded material in the extrusion die, thereby preventing a void from being generated in the extrusion die. . As a result, an appearance defect and a surface roughness defect do not occur in the extruded material, and thus an extruded material having a good appearance and a small surface roughness can be produced.

  Furthermore, since this extrusion processing method includes a release agent coating step, it is possible to reliably prevent a void from being generated in the extrusion die. The reason is as follows.

  In this extrusion method, the discard may adhere to the pressing surface of the stem due to seizure or the like due to the force of pressing the discard by the stem in the discard thickness reducing step. If the stem is moved in the direction opposite to the discard pressing direction with the discard attached to the pressing surface of the stem, a part of the remaining extruded material in the extrusion die is scraped off by the movement of the stem. There is a risk (see FIG. 6), and as a result, a void is formed in the extrusion die. However, according to this extrusion processing method, the discard adheres to the pressing surface of the stem by applying the releasing agent to at least one of the pressing surface of the stem and the upstream end surface of the billet in the releasing agent application step. Can be prevented by the mold release agent, so that a part of the remaining extruded material in the extrusion die is not torn off. Therefore, it is possible to reliably prevent a void from being generated in the extrusion die. As a result, an appearance defect and a surface roughness defect do not occur reliably in the extruded material, and thus an extruded material having a good appearance and a small surface roughness can be reliably produced.

  In the extrusion method of [2], it is possible to reliably prevent the discard from adhering to the pressing surface of the stem.

  In the extrusion method of [3], it is possible to more reliably prevent the discard from adhering to the pressing surface of the stem.

  In the extrusion method of [4], an extruded material having a good appearance and a small surface roughness can be produced more reliably.

  In the extrusion method of [5], an aluminum alloy extruded material having a good appearance and a small surface roughness can be reliably produced.

  In the method for producing a photosensitive drum substrate blank according to [6], the extruded tube obtained by any one of the extrusion methods according to [1] to [5] has a small surface roughness. By drawing, a photosensitive drum base tube having a small surface roughness can be obtained.

  The extrusion apparatus of [7] can provide an extrusion apparatus suitably used for the extrusion method of any one of [1] to [5].

FIG. 1A is a schematic cross-sectional view of an extrusion apparatus during a release agent coating process in the extrusion method according to an embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view during a billet pressing process. FIG. 2A is a schematic cross-sectional view showing a state in which the discard remains in the container, and FIG. 2B is a schematic cross-sectional view showing a state where the restraint of the outer peripheral surface of the discard by the container is released. FIG. 3A is a schematic cross-sectional view of a state where the billet is pressed by a stem to reduce the thickness of the billet, and FIG. 3B is a schematic cross-sectional view of a state immediately before the discard is cut by a shear blade. It is. FIG. 4A is a schematic diagram of the state where the discard is being cut with a shear blade, FIG. 4B is a schematic diagram of the state immediately before the cutting of the discard, and FIG. 4C is the discard. It is the schematic of the state at the time of completion | finish of cutting | disconnection. FIG. 5 is a schematic perspective view of the stem and billet. FIG. 6 is a schematic cross-sectional view of a state where a discard is attached to the pressing surface of the stem. FIG. 7 is a schematic cross-sectional view of the drawing apparatus in a state where the extruded tube (extruded material) is drawn. FIG. 8 is a schematic cross-sectional view showing a state in the middle of pressing the discard while releasing the restraint of the outer peripheral surface of the discard by the container. FIG. 9A is a schematic view of a state immediately before the discard is cut with a shear blade in the conventional extrusion method, FIG. 9B is a schematic view of a state during cutting of the discard, and FIG. 9C. FIG. 4 is a schematic view of a state at the end of cutting of the discard card.

  Next, several embodiments of the present invention will be described below with reference to the drawings.

  1-6 is a figure for demonstrating the extrusion method and extrusion apparatus which concern on one Embodiment of this invention. In FIG. 1A, reference numeral 10 denotes an extrusion apparatus according to an embodiment of the present invention. The extrusion apparatus 10 is a direct extrusion apparatus in detail. As shown in FIG. 2A, an extruded material 20 produced by the extrusion processing apparatus 10 is a hollow extruded material (eg, pipe) used for a photosensitive drum substrate blank, an OA component, a building material, an exterior material, and the like. And has a hollow portion extending continuously in the extrusion direction E. In the present embodiment, the extruded material 20 is an extruded tube having an annular cross section, and an extruded tube used for the photosensitive drum substrate is obtained by drawing the extruded tube. When manufacturing the photosensitive drum base, an OPC (Organic Photo Conductor) layer, for example, is coated on the outer peripheral surface of the base tube. The material of the extruded material 20 is a metal, and more specifically, for example, aluminum. Hereinafter, the extruded material 20 is referred to as an “extruded tube 20”.

  As shown in FIG. 1 (a), the extrusion processing apparatus 10 includes a container 1, a stem 2, an extrusion die 3, a shear blade 4, a release agent coating means 9, and the like.

  The container 1 is loaded with an aluminum billet 6 therein. The container 1 has a function of guiding and moving the billet 6 pressed by the stem 2 toward the extrusion die 3 and the outer peripheral surface of the billet 6 expands radially outward even when the billet 6 receives the pressing force from the stem 2. It has a function of restraining the outer peripheral surface of the billet 6 so as not to come out. In these drawings, the billet 6 (and the discard 7) is illustrated by dot hatching so as to be easily distinguished from other members.

  The diameter and length of the billet 6 loaded in the container 1 are set according to the diameter, thickness and length of the extruded tube 20 and are not particularly limited. Is usually 155 to 205 mm, and its length is usually 300 to 790 mm.

  The stem 2 presses the billet 6 in the container 1. A driving means 5 such as a fluid pressure cylinder (for example, a hydraulic cylinder) for applying a pressing force to the stem 2 is connected to a base end portion of the stem 2 (that is, an upstream end portion of the stem 2). A dummy block 2 a is provided at the distal end portion of the stem 2 (that is, the downstream end portion of the stem 2). The dummy block 2a is used to prevent the billet material (extrusion material) from flowing backward when the billet 6 is pressed by the stem 2. The pressing surface 2z of the stem 2 against the billet 6 is composed of the tip end surface of the stem 2 (that is, the downstream end surface of the stem 2), more specifically, the downstream end surface of the dummy block 2a.

  The extrusion die 3 has a forming hole 3b, a port hole 3c, a weld chamber, and the like for forming the extruded tube 20 from the billet 6 therein (see FIG. 4). In the present embodiment, the extrusion die 3 is composed of a port hole die or the like, and is arranged in a state held by a die holder (not shown) on the downstream side of the container 1. Further, the upstream end surface 3a of the extrusion die 3 functions as a cutting reference surface when cutting and removing (that is, cutting) the discard 7 composed of the billet 6 remaining in the container 1. An end platen (not shown) is disposed downstream of the extrusion die 3.

  The shear blade 4 cuts and removes the discard 7 along the upstream end surface 3 a (that is, the cutting reference surface) of the extrusion die 3. The shear blade 4 is disposed on the side with respect to the position of the upstream end face 3 a of the extrusion die 3.

  As shown in FIG. 5, the release agent coating means 9 is applied with brush, roller coating, stamp transfer coating, spraying on at least one of the pressing surface 2z of the stem 2 against the billet 6 and the upstream end surface 6z of the billet 6. The release agent 8 is applied by coating or the like, and includes a brush, a roller, a stamp member, a spray, and the like for applying the release agent 8. In FIG. 5, the portion to which the release agent 8 is applied is shown by cross hatching.

  The release agent 8 acts as a discard adhesion preventing agent for preventing the discard 7 from adhering to the pressing surface 2z of the stem 2. As the release agent 8, a commercially available product such as a graphite-based, molybdenum-based, or BN-based release agent is preferably used.

  Further, the stem 2 is placed in the thickness direction (that is, the length direction of the billet 6) after the restraint of the outer peripheral surface of the discard 7 by the container 1 is released or released by the driving means 5. The thickness of the discard 7 is reduced by pressing it.

  Next, a method for extruding aluminum using the extrusion apparatus 10 will be described below.

  First, as shown in FIG. 1A, before the billet 6 loaded in the container 1 is pressed by the stem 2, it is separated from at least one of the pressing surface 2z of the stem 2 and the upstream end surface 6z of the billet 6. The mold 8 is applied by the release agent applying means 9. This process is referred to as a “release agent coating process”. In the present embodiment, the release agent 8 is applied to the pressing surface 2z of the stem 2 and the upstream end surface 6z of the billet 6, respectively.

  Here, as shown in FIG. 5, the release agent 8 is desirably applied to a portion of the pressing surface 2 z of the stem 2 excluding the outer peripheral edge 2 y. By doing so, it is possible to prevent the release agent 8 from adhering to the inner peripheral surface of the container 1, thereby reducing the quality of the extruded tube 20 due to the release agent 8 being caught in the billet 6. Can be prevented. For the same reason, it is desirable that the release agent 8 is applied to a portion of the upstream end surface 6z of the billet 6 excluding the outer peripheral edge 6y.

  The release agent 8 is preferably applied to the pressing surface 2z of the stem 2 so that the application area of the releasing agent 8 with respect to the area of the pressing surface 2z of the stem 2 is 50% or more. It is desirable to apply to the upstream end face 6z of the billet 6 so that the application area of the release agent 8 with respect to the area of the end face 6z is 50% or more. By doing so, it is possible to reliably prevent the discard 7 from adhering to the pressing surface 2z of the stem 2.

  Furthermore, it is desirable to apply the release agent 8 so that the thickness of the release agent application layer is 500 μm or less, and it is preferable to apply the release agent 8 so that the thickness is uniform.

  In FIG. 1A, the billet 6 is placed on a billet charger (not shown) in a heated state. Then, the release agent 8 is applied to the upstream end face 6 z of the billet 6 by the release agent application means 9. The stem 2 is disposed upstream of the container 1. The billet 6 to which the release agent 8 is applied is set on a billet loader (not shown) by a billet charger. Until the billet 6 is set on the billet loader, the release agent 8 is applied to the pressing surface 2z of the stem 2 by the release agent application means 9.

  Next, as shown in FIG. 1B, the billet 6 is loaded into the container 1 by the billet loader. Then, the billet 6 is pressed in the extrusion direction E by the stem 2. Thereby, the billet 6 is passed through the extrusion die 3 (more specifically, the forming hole 3b of the extrusion die 3), and the extruded tube 20 is formed. This process is referred to as a “billet pressing process”.

  In this billet pressing step, when the billet 6 is loaded in the container 1, the outer peripheral surface of the billet 6 does not bulge radially outward by the container 1 even if the billet 6 receives a pressing force from the stem 2. It is restrained. In the present embodiment, since the extrusion apparatus 10 is a direct extrusion apparatus as described above, the pressing direction of the billet 6 by the stem 2 is the extrusion direction E.

  As shown in FIG. 2A, when the billet 6 remaining in the container 1 reaches a predetermined length, the pressing by the stem 2 is stopped. The billet 6 remaining in the container 1 at this time becomes a discard 7 to be excised, and the length of the remaining billet 6 is the thickness of the discard 7. In the discard 7, an impurity layer of the billet skin that has flowed backward due to the container wall resistance during the extrusion process is entrained. Therefore, the discard 7 contains a large amount of impurities. Although the thickness of the discard 7 at this time is not limited, it is particularly desirable to be within a range of 20 to 60 mm. When the thickness of the discard 7 is 20 mm or more, the discard 7 can surely contain impurities. When the thickness of the discard 7 is 60 mm or less, waste of the extruded material can be reduced as much as possible.

  Next, as shown in FIG. 2 (b), the container 1 is moved in the direction opposite to the extrusion direction E, that is, the container 1 is retracted, whereby the discard 7 is moved from the container 1 to the downstream outlet of the container 1. To the outside of the container 1, thereby releasing the restraint of the outer peripheral surface of the discard 7 by the container 1. This process is called “discard restraint release process”. The discard 7 is integrally connected to the residual extruded material in the extrusion die 3 in a state protruding from the upstream end surface 3a of the extrusion die 3 to the upstream side.

  Next, as shown in FIG. 3A, the discard 2 is pressed by the stem 2 in the thickness direction (the extrusion direction E in the present embodiment), thereby reducing the thickness of the discard 7 and making it thin. . That is, the discard 7 is plastically deformed so that its thickness decreases. As the thickness of the discard 7 decreases, the outer peripheral surface of the discard 7 bulges outward in the radial direction over the entire circumference, and the diameter of the discard 7 increases. This process is called “discard thickness reduction process”.

  In the discard thinning step, when the billet 6 is an aluminum alloy billet, that is, when the extrusion method is an aluminum alloy extrusion method, the temperature of the discard 7 when pressing the discard 7 with the stem 2 is 400. It is desirable to set within a range of ˜520 ° C. When the temperature of the discard 7 is 520 ° C. or lower, the adhesion between the stem 2 and the discard 7 can be reliably prevented. On the other hand, when the temperature of the discard 7 is too low, the thickness of the discard 7 does not decrease so much even if the discard 7 is pressed by the stem 2, and impurities contained in the discard 7 are contained in the extrusion die 3. There is a possibility that a problem of being pushed into the residual extruded material may occur. Therefore, the temperature of the discard 7 is preferably set within a range of 400 to 520 ° C. In particular, when the billet 6 is made of an aluminum alloy having an aluminum concentration of 90% or more, the temperature of the discard 7 when pressing the discard 7 with the stem 2 is preferably set within a range of 420 to 490 ° C. .

  Furthermore, in the discard thickness reducing step, it is desirable to reduce the discard 7 so that the thickness thereof falls within the range of 10 to 30 mm. When the thickness of the discard 7 is 10 mm or more, the discard 7 can be easily cut, and furthermore, impurities contained in the discard 7 are surely pushed into the residual extruded material in the extrusion die 3. Can be prevented. When the discard 7 has a thickness of 30 mm or less (including 30 mm), the discard 7 is surely curled when the discard 7 is cut. As a result, the discard 7 remains in the extrusion die 3. It can be surely prevented from falling off with a part of the material.

  Next, as shown in FIG. 3B, the pressing of the discard 7 with the stem 2 is stopped by moving the stem 2 in the direction opposite to the extrusion direction E, that is, by retracting the stem 2. Thereafter, the shear blade 4 is advanced from the side toward the upstream end face 3 a of the extrusion die 3.

  4A to 4C, the shear blade 4 is advanced along the upstream end surface 3a of the extrusion die 3 so that the discard 7 is moved upstream of the extrusion die 3 by the shear blade 4. Cut along the end face 3a. At this time, since the thickness of the discard 7 is already reduced and thinned, the discard 7 is easily curled. For this reason, as the cutting of the discard 7 by the shear blade 4 proceeds, the discard 7 curls toward the upstream side. Thereby, even if the discard 7 is cut, the discard 7 does not fall off together with a part of the remaining extruded material in the extrusion die 3. Accordingly, the discard 7 is cut so that the cut surface of the remaining extruded material in the extrusion die 3 becomes flat. This process is called “discard cutting process”. In FIGS. 4A to 4C, the container 1 and the stem 2 are not shown.

  Next, although not shown, the container 1 is returned to the initial position, and a new billet 6N (see FIG. 1B) is loaded into the container 1. Thereafter, the stem 2 is advanced to press the new billet 6N in the length direction (that is, the extrusion direction E), thereby pressing the new billet 6N against the remaining extruded material in the extrusion die 3 and crimping it. This process is called “new billet push-in process”. Then, the extrusion process is resumed. This process is referred to as an “extrusion restart process”.

  According to the above extrusion processing method, the discard 7 is easily curled when the discard 7 is cut because the discard 7 is already reduced in thickness in the discard cutting step. Therefore, the discard 7 can be cut so that the cut surface of the remaining extruded material in the extrusion die 3 becomes flat. Thereby, even if it pushes in the new billet 6N, the appearance defect and surface roughness defect do not generate | occur | produce in the extrusion pipe | tube 20 obtained. Therefore, it is possible to obtain the extruded tube 20 having a good appearance and a small surface roughness.

  Furthermore, since this extrusion processing method includes a release agent coating step, it is possible to reliably prevent a void from being generated in the extrusion die 3. The reason is as follows.

  In this extrusion method, the discard 7 may adhere to the pressing surface 2z of the stem 2 due to seizure or the like due to the force of pressing the discard 7 by the stem 2 in the discard thickness reducing step. If the stem 2 is moved in the direction opposite to the discard pressing direction with the discard 7 attached to the pressing surface 2z of the stem 2, as shown in FIG. In addition, there is a risk that a part 11 of the remaining extruded material in the extrusion die 3 (more specifically, the port hole 3c of the extrusion die 3) is torn off. As a result, a void x is formed in the extrusion die 3. However, since the release agent 8 is applied to at least one of the pressing surface 2z of the stem 2 and the upstream end surface z of the billet 6 in the release agent application step, the discard 7 adheres to the pressing surface 2z of the stem 2. This can be prevented by the release agent 8, so that a part 11 of the remaining extruded material in the extrusion die 3 is not torn off. Therefore, it is possible to reliably prevent the void x from occurring in the extrusion die 3. As a result, the appearance defect and the surface roughness defect do not occur reliably in the extruded tube 20, and the extruded tube 20 having a good appearance and a small surface roughness can be reliably manufactured.

  The extruded tube 20 thus obtained is subjected to drawing in accordance with a conventional method using, for example, a drawing device 30 shown in FIG. 7 as a known drawing device (not shown). 39 is obtained. This process is called “drawing process”.

  In FIG. 7, reference numerals 31 and 32 denote a drawing die and a plug of the drawing apparatus 30, respectively. The drawing die 31 is for reducing the diameter of the extruded tube 20 to a predetermined outer diameter, and the extruded tube 20 is passed through a die hole of the drawing die 31. The extraction plug 32 is disposed in the extruded tube 20. Reference numeral 33 denotes a nozzle as lubricating oil supply means for supplying lubricating oil (processing oil) 33 a to the extruded tube 20. Reference numeral 35 denotes traction means for pulling the extruded tube 20 in the drawing direction N. The pulling means 35 has a chuck part 35a for chucking the mouthpiece 21 formed at the tip of the extruded tube 20, and a drive source 35b for applying a pulling force to the chuck part 35a.

  Since the photosensitive drum base tube 39 made of the drawn tube obtained by this drawing process is obtained by drawing the extruded tube 20 having a small surface roughness, the surface roughness is also small. . Furthermore, since the surface roughness defect in the axial direction of the raw tube 39 is not stretched, a long linear defect does not appear in the printed image, and a good printed image can be obtained. Therefore, this elementary tube 39 is preferably used for a photosensitive drum substrate.

  Furthermore, in the extrusion processing apparatus 10 of this embodiment, the area of the pressing surface 2z of the stem 2 is set to be smaller than the projected direction projected area of the discard 7 after the discard thickness reduction process. In this embodiment, the shape of the pressing surface 2z of the stem 2 is a circle. The radius of the pressing surface 2z is set to be smaller than the minimum radius in the projection direction projection shape of the discard 7 after the discard thinning process. By doing so, the discard 7 can be curled reliably.

  Although one embodiment of the present invention has been described above, the present invention is not limited to that shown in the above embodiment, and various modifications can be made.

  For example, according to the above embodiment, in the discard thickness reducing step, after releasing the restraint of the outer peripheral surface of the discard 7 by the container 1, the discard 7 is pressed by the stem 2 in its thickness direction, The thickness of the discard 7 is reduced. However, in the present invention, as shown in FIG. 8, the discard 7 is pressed by the stem 2 in the thickness direction while releasing the restraint of the outer peripheral surface of the discard 7 by the container 1. The thickness of the card 7 may be reduced. In FIG. 8, by moving the stem 2 while retreating the container 1, the discard 7 is pressed by the stem 2 in the thickness direction while releasing the restraint of the outer peripheral surface of the discard 7.

  Further, in the extrusion method of the above embodiment, the release agent coating step is performed every time the billet 6 is loaded in the container 1 to reliably prevent the discard 7 from adhering to the pressing surface 2z of the stem 2. This is desirable because it can be done. However, in the extrusion method of the present invention, the release agent 8 is applied to at least 50% of the upstream end surface 6z of the billet 6 out of the pressing surface 2z of the stem 2 and the upstream end surface 6z of the billet 6. In this case, the release agent coating step is not necessarily performed every time the billet 6 is loaded into the container 1, that is, the billet 6 is loaded a plurality of times. The release agent coating step may be performed once (preferably 2 to 5 times).

  Moreover, in the said embodiment, although the extrusion die 3 is for manufacturing the extrusion pipe | tube 20, in this invention, even if the extrusion die 3 is for manufacturing a solid extruded material, good. Examples of the extrusion die 3 for producing a solid extruded material include a flat die and a flat die having a push plate attached thereto.

  In the above embodiment, the extrusion apparatus 10 is a direct extrusion apparatus. However, in the present invention, the extrusion apparatus may be an indirect extrusion apparatus.

  Further, in the above embodiment, the photosensitive drum base material tube is obtained by drawing out the extruded tube 20, but in the present invention, in addition, the photosensitive drum base material is obtained by cutting the outer peripheral surface of the extruded tube 20. You may get a tube. In this case, since the surface roughness of the extruded tube 20 is small, the machining allowance for cutting is small, and the material yield is good.

  Next, specific examples and comparative examples of the present invention are shown below. In addition, in order to make it easy to understand an Example and a comparative example, the same code | symbol as the said embodiment is attached | subjected to the following explanatory notes.

<Examples 1-9>
In Examples 1 to 9, the extruded tube 20 was manufactured by extrusion according to the extrusion method of the above embodiment. The extrusion process conditions applied at that time are as follows.

  The outer diameter of the extruded tube 20 is 35 mm, and the wall thickness of the extruded tube 20 is 1 mm. The billet 6 which is a material of the extruded tube 20 is made of an aluminum alloy (alloy number: A3003). The billet 6 has a diameter of 155 mm and the billet 6 has a length of 500 mm. The temperature of the billet 6 at the time of a billet pressing process is 450 degreeC. The extrusion speed is 50 m / min. The temperature of the discard 7 during the discard thinning process is about 430 ° C. The thickness of the discard 7 before reducing the thickness of the discard 7 is 60 mm, and the thickness of the discard 7 after reducing the thickness of the discard 7 is 20 mm. The release agent 8 used is a graphite-based one.

  In Table 1, “application area ratio” means the application area of the release agent 8 relative to the area of the surface to which the release agent 8 is applied (that is, the pressing surface 2z of the stem 2 and the upstream end surface 6z of the billet 6). It is a ratio. That is, when the area of the surface on which the release agent 8 is applied is S and the area where the release agent 8 is applied is A, the application area ratio R is calculated as A / S.

  In Examples 1 to 3, the release agent 8 was applied to the pressing surface 2z of the stem 2, but the release agent 8 was not applied to the upstream end surface 6z of the billet 6.

  In Examples 4 to 6, the release agent 8 was not applied to the pressing surface 2z of the stem 2, but the release agent 8 was applied to the upstream end surface 6z of the billet 6.

  In Examples 7 to 9, the release agent 8 was applied to the pressing surface 2z of the stem 2 and the upstream end surface 6z of the billet 6, respectively.

  In each of Examples 1 to 9, the application area ratio of the release agent 8 is as shown in the “application area ratio” column of Table 1.

  In each of Examples 1 to 9, the total number of extrusion processes (that is, the total number of times the billet 6 is loaded into the container 1) is 20 times.

  And in each Example 1-9, when the stem 2 is evacuated after the discard thickness reducing step, the discard 7 adheres to the pressing surface 2z of the stem 2 so that the remaining extruded material in the extrusion die 3 The incidence of demolition was examined. The results are shown in the “Evaluation” column in Table 1.

  Here, in the evaluation column, “every time application” means that the release agent is applied every time the billet is loaded into the container, that is, every time the billet is loaded into the container. , "Apply once every 5 times" means that the release agent was applied at a rate of once every 5 times the billet was loaded into the container. "Apply once every 10 times" Means that the release agent was applied at a rate of once every 10 times the billet was loaded into the container. Further, “◯” means that the occurrence rate of the remaining extruded material in the extrusion die 3 is 0%, and “△” means that the occurrence rate is 10% or less. , “X” means that the occurrence rate exceeds 10%.

<Comparative Example 1>
In Comparative Example 1, an extruded tube was used under the same extrusion conditions as in Examples 1 to 9, except that the release agent 8 was not applied to the pressing surface 2z of the stem 2 and the upstream end surface 6z of the billet 6, respectively. 20 was produced by extrusion. Then, similarly to Examples 1 to 9, the occurrence rate of the remaining extruded material in the extrusion die 3 was examined. The results are shown in the evaluation column in Table 1.

[Comprehensive evaluation]
As shown in the evaluation column of Table 1, in Examples 1 to 9, the rate of scraping of the remaining extruded material in the extrusion die 3 was smaller than that in Comparative Example 1. Therefore, it was possible to prevent the void x from being generated in the extrusion die 3.

  INDUSTRIAL APPLICABILITY The present invention can be used for an extrusion method, an extrusion processing apparatus, and a method for manufacturing a photosensitive drum base tube.

1: Container 2: Stem 2z: Pressing surface of stem 3: Extrusion die 4: Shear blade 6: Billet 6z: Upstream end surface of billet 7: Discard 8: Release agent 9: Release agent application means 10: Extrusion Apparatus 20: Extruded tube (extruded material)
39: Base tube E for photosensitive drum substrate: Extrusion direction x: Empty space

Claims (7)

A billet pressing step in which the billet loaded in the container is pressed by a stem to pass the billet into an extrusion die and form an extruded material;
About the billet discard remaining in the container after the billet pressing step, after releasing or releasing the restraint of the outer peripheral surface of the discard by the container, the discard in the thickness direction A discard thickness reducing step for reducing the thickness of the discard by pressing the stem,
After the discard thickness reducing step, a discard cutting step of cutting the discard with a shear blade;
Before the billet pressing step, a release agent for preventing the discard from adhering to the pressing surface is applied to at least one of the pressing surface of the stem to the billet and the upstream end surface of the billet. A release agent coating process;
An extrusion method comprising the steps of:   The said release agent application | coating process apply | coats the said release agent to the at least one of the said press surface and the upstream end surface of the said billet so that the application area of the release agent with respect to the area may be 50% or more. The extrusion method according to 1.   The extrusion method according to claim 1 or 2, wherein, in the release agent application step, the release agent is applied to the pressing surface and the upstream end surface of the billet, respectively. After the discard cutting step, a new billet push-in step for pressing and pressing the new billet loaded in the container against the remaining extruded material in the extrusion die;
After the new billet splicing process, an extrusion process restarting process for restarting the extrusion process,
The extrusion method according to any one of claims 1 to 3. The extrusion method is an aluminum alloy extrusion method,
The extrusion method according to any one of claims 1 to 4, wherein a temperature of the discard in the discard thickness reducing step is in a range of 400 to 520 ° C.   A method for producing a photosensitive drum base tube, wherein the extrusion tube obtained by the extrusion method is drawn after the extrusion method according to any one of claims 1 to 5. A container,
A stem for pressing the billet loaded in the container;
A shear blade for cutting out the billet discard;
A release agent applying means for applying a release agent for preventing the discard from adhering to the pressing surface on at least one of the pressing surface of the stem to the billet and the upstream end surface of the billet; Equipped,
The stem is further configured to press the discard in the thickness direction so that the thickness decreases after or after the restraint of the outer peripheral surface of the discard by the container is released. An extrusion apparatus characterized by that.

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