JP2008161895A - Extrusion method and extrusion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a homogeneous extruded material free from any defect of surface property over the total length of the extruded material. <P>SOLUTION: The temperature of a billet, in particular, a front end thereof is measured immediately before the billet is charged in a container. The measured value of the temperature is compared with the preset adequate extrusion temperature range. Only when the measured value adaptively falls in the adequate temperature range, the billet is charged in the container to start the extrusion. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an extrusion method and apparatus for extruding a billet made of a metal material, particularly aluminum or an alloy thereof, into an extruded material having a predetermined cross-sectional shape.

  In the present specification, the term “aluminum” is used hereinafter to include its alloys.

  Aluminum extruded materials are often used as parts for various office automation equipment such as photosensitive drums used in electronic copying machines and printers. In recent years, extruded materials for these applications tend to require more advanced materials in terms of quality accuracy. In particular, an extruding element tube used as a substrate for a photosensitive drum, an extruded material subjected to alumite treatment, and the like are required to have particularly strict surface properties.

  For extrudates for use as described above, for example, in the case of a photosensitive drum base tube, an A3003 aluminum alloy billet is extruded into a tubular extrudate of a predetermined size using a porthole die, and then this is further drawn. And processed into a pipe material having the required dimensional accuracy.

 However, pipes and the like that have been manufactured through the above-described processing steps have not been adapted to quality requirements for some of the products in the products, even if they are manufactured under the same processing conditions as the same material. It was recognized that there was a problem that products were mixed and the actual yield was inevitably lowered.

  Most of the defects that do not meet the required performance are due to the surface roughness of the extruded material and the coarsening of the crystal grains, the surface roughness becomes large after drawing, or the appearance becomes whitish, A pattern (macro pattern) due to coarsening of the crystal grains appears on the surface after the alumite treatment, resulting in poor appearance.

  Therefore, we investigated the cause of the coarsening of the surface crystal grains of the extruded material, which was caused by various changes in the extrusion conditions. As a result, a new billet was loaded into the extruder container and continuous extrusion resumed. Thus, the present invention has been completed by finding that the billet temperature at the initial stage of extrusion is greatly affected.

Conventionally, an “isothermal extrusion” technique for controlling the billet temperature and the extrusion speed has been established as a method for obtaining stable quality over the entire length of the extruded material. In this isothermal extrusion method, as shown in Patent Documents 1 and 2 below, the temperature of the extruded product on the outlet side of the die is continuously measured by a temperature measuring means provided on the outlet side of the platen, and this measured product temperature is measured. The extrusion speed is constantly controlled so that is constant.
Japanese Patent No. 3770169 Japanese Patent No. 3823895

  However, the use of such an isothermal extrusion method not only increases the equipment cost for that, but even if the isothermal extrusion method is used, the occurrence of surface property defects as described above is completely eliminated. However, there is a problem in that an extruded material part having a failure factor that still appears after the drawing process may be mixed in a part of the extruded material product extruded with a single billet.

  In addition, in products manufactured using an extruder not equipped with an isothermal extrusion device, the incidence of such defective products tended to be higher.

  The present invention is effective in generating the surface property defects of the extruded material, particularly those having a large surface roughness or a crystal grain coarsening site under the background of the prior art as described above. It is an object of the present invention to provide an extrusion method capable of obtaining a high-quality and homogeneous extruded material over the entire length, and an extrusion apparatus used therefor.

  Furthermore, another object of the present invention is to provide an extrusion method capable of stabilizing the quality of the extruded material as described above without necessarily introducing an expensive isothermal extrusion system.

  In response to the problems as described above, the present inventors have conducted research by paying attention to various changing factors of actual extrusion conditions, and it has been found that the following factors exist.

  That is, the billet is heated to a predetermined temperature suitable for extrusion by a billet heater before extrusion, and then transferred to a billet charger attached to the extruder by a billet call. It is usual to be in a standby state until one extrusion is completed. When extrusion by the preceding billet is completed, the billet waiting on the billet charger is transferred to the billet loader positioned along the axis of the extrusion slam based on the billet charging call, and then the slam is driven forward. Thus, the container is loaded into the container, and the next push-push extrusion process is started.

  However, in practice, it has been found that when the billet is heated by the billet heater until the billet is loaded into the container of the extruder, it has a considerable variation. This variation may not only be quite large due to troubles during the transportation of the billet itself or troubles in the transportation of the extruded material at the rear equipment of the extruder, but also occurs to some extent during steady operation. ing.

  The billet temperature decreases due to natural heat radiation as the time from the completion of the heating to the loading of the container becomes longer due to such a variation in the waiting time. For this reason, there may occur a situation in which a billet having a temperature lower than the expected proper extrusion temperature is rarely loaded in the container, and the temperature rises due to the progress of the extrusion process especially when the billet is restarted. In the initial stage up to this point, an extruded material having defects in surface properties and internal structure may be extruded. In particular, regarding the defects in the internal structure, since the presence of the defects cannot be determined from the appearance of the extruded product, it becomes apparent after the drawing process of the next process or after the alumite treatment, resulting in the final product. This increases the incidence of defective products.

  The present invention presents the following means for solving the above-mentioned problems, based on the cause elucidation focusing on the actual field work.

[1] An appropriate temperature range of the billet temperature in the extrusion process conditions is set in advance,
Measure billet temperature just before the container is loaded with billet,
The measured value of the billet temperature is compared with the preset appropriate temperature range, and only when the measured temperature is within the appropriate temperature range, the billet is loaded into the container and the extruded material is extruded. Extrusion method characterized by performing.

  [2] The extrusion method according to [1], wherein the billet is a 3000 series aluminum alloy.

  [3] The extrusion method according to [1] or [2], wherein the extruded material is an aluminum tube material.

  [4] The extrusion method according to [2] or [3], wherein the proper temperature range of the billet temperature is set to 350 to 520 ° C. to perform extrusion.

  [5] Any one of [1] to [4] above, wherein the billet temperature is measured at the front end in the extrusion direction of the billet mounted on the billet carrier after the heat treatment. 2. Extrusion method described in 2.

  [6] The extrusion method according to [5], wherein the billet temperature is measured using a thermocouple.

  [7] The extrusion method according to any one of [2] to [6], wherein the extrusion speed is set in a range of 5 to 70 m / min and extrusion is performed.

  [8] The extrusion method according to any one of [2] to [7], wherein the extruded material is an elemental tube for a photosensitive drum.

[9] A temperature measuring means for measuring the temperature of the billet after the heat treatment mounted on the billet charger,
Means for setting an appropriate temperature range of the billet temperature in the extrusion processing conditions;
Comparing the measured value of the billet temperature measured by the temperature measuring means with the appropriate temperature range, and loading the billet on the billet charger into the container only when the measured value is within the appropriate temperature range. An extrusion apparatus comprising drive control means for executing.

  [10] The extrusion processing apparatus according to [9], wherein the billet temperature measuring means measures the temperature of the front end portion in the extrusion direction of the billet mounted on the billet carrier.

  [11] The extrusion apparatus according to [10], wherein the temperature measuring means includes a thermocouple installed so as to be capable of moving forward and backward with respect to a front end face of the billet on the billet carrier.

  [12] Any one of [9] to [11] above, further comprising alarm means for giving a warning not to load the billet into the container when the measured value of the billet temperature deviates from the appropriate temperature range. Extrusion processing equipment.

  In the extrusion method of the above item [1], an appropriate temperature range for billet extrusion, which has been empirically determined in advance, that is, a temperature range in which coarse portions of crystal grains and internal structure defect portions do not occur in the extruded material. If the billet is called after a previous billet has been extruded, even if the measured billet temperature is an extrudable temperature, the above-mentioned proper extrusion temperature range is set. In the case of detachment, the billet is not loaded into the container. Therefore, there is no risk that the billet temperature has dropped below the proper temperature for some reason and the billet is loaded into the container as it is and extruded, and as a result, it is possible to reliably avoid the occurrence of unintentional property defects in the extruded material. sell.

  In addition, the billet temperature measurement performed immediately before the container loading and the billet loading operation control mechanism based on the result can be carried out, so that it is extremely inexpensive as compared with the case of using an expensive isothermal extrusion system. It is also advantageous in that it can be executed at a low equipment cost.

  The above processing method can be particularly advantageously applied to the extrusion of aluminum pipe material from a billet using an A3003 aluminum alloy, as described in the above items [2] and [3].

  In that case, as described in the items [4] and [7], the extrusion proper temperature is set to 350 to 520 ° C. and the extrusion speed is set to a range of 5 to 70 m / min. By carrying out the processing method, it is possible to obtain a homogeneous extruded material having no surface texture defects over the entire length.

  Further, as described in the above item [5], the billet temperature measurement performed immediately before loading into the container is performed at the front end of the billet in the extrusion direction. Even in the region near the tip of the unit extruded material, an extruded material having no surface defects can be obtained.

  The above temperature measurement is performed with a contact-type thermometer using a thermocouple as a temperature measuring element, as described in [6] above. This is advantageous in that a billet temperature can be measured.

  Therefore, when manufacturing the photosensitive drum base tube as described in the above item [8] using the extrusion method as described in each of the above items, the yield rate of the product is improved, and the substantial manufacturing is achieved. Cost can be further reduced.

  The items [9] to [12] relate to an extrusion apparatus for carrying out the above-described extrusion method, and by using the extrusion apparatus described in each of these items, the above processing method is surely and accurately performed. Can be executed.

  Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is an explanatory plan view showing an outline of the configuration of an extrusion apparatus according to the present invention.

  In the figure, (1) is an extruder, (2) is its container, (3) is a die, and (4) is a die slide.

  A billet loader (5) capable of supporting the billet (B) is provided on the same axis as the container (2) behind the container (2) (based on the extrusion direction). The stem (6) of the extruder (1) can be moved backward to the rear position of the billet loader (5) during billet replacement, and the billet (B) placed on the billet loader (5) ) Can be pushed into the container (2) on the basis of the billet charging call.

  On the other hand, at the side position of the billet loader (5), a billet charger (7) for waiting for the billet (B) before loading the container is provided.

  The above-described configuration is the same as that of a conventional extrusion device. However, in the present invention, a temperature measuring device that can detect the temperature of the front end face in the extrusion direction of the billet (B) carried on the billet charger (7) ( 10).

  This temperature measuring device (10) is a contact-type temperature measuring device using a thermocouple (10a) as a temperature measuring element at the tip, and is always waiting at a distance in front of the billet charger (7). When the billet is transported, the thermocouple (10a) is moved forward to contact the front end surface of the billet (B), and temperature measurement is continuously performed until a billet charging call is made to the container. ing.

  The measured value of the billet temperature by the temperature measuring device (10) is transmitted to the billet charging control device (11), and compared with the preset appropriate temperature range for billet extrusion, Only when the measured temperature is suitable for the predetermined billet loading operation, the billet (B) is loaded into the container (2). Therefore, the control device (11) is capable of variably setting the proper temperature range of the billet in particular in the extrusion conditions obtained from past extrusion results, and means for storing the appropriate temperature range. In addition, the calculation means for comparing with the measured temperature and the drive of the billet charger (7) are controlled based on the result, and when the measured value is out of the appropriate temperature range, the billet (B) is transferred to the container ( 2) is provided with warning means for warning not to load. More preferably, when the measured value deviates from the appropriate temperature range as described above, the ejector device for removing the billet (B) waiting on the billet charger (7) outside the loading transfer line can be activated. May be made.

  When manufacturing an extruded material having a predetermined cross-sectional shape with a metal material such as aluminum, the metal material billet (B) is heated in advance by a billet heater. Then, after this heating, the container (2) is loaded on the basis of the billet charging call from the extruder (1) side, and the extrusion process is started.

  The process flow of the extrusion method according to the present invention from the heating of the billet (B) to the loading into the container (2) and the start of extrusion is shown as a flowchart in FIG.

  In FIG. 2, the billet (B) heated by the billet heater is unloaded from the billet heater based on the billet call (step S1) and transferred to the billet charger (7) (step S2). Waiting, the temperature of the billet front end is measured by the temperature measuring device (10) (step S3).

  Then, after the extrusion by the preceding billet (B) is completed, when a billet insertion call is issued in order to load the next billet (B) into the container (2), the measured value of the above temperature is determined by the control device ( 11) and is compared with the proper extrusion temperature range preset in the control device (11) (step 5). If this is within the proper temperature range (in the case of OK in step 5), the billet ( The container loading operation of B) is executed. That is, the billet (B) is transferred onto the billet loader (5) (step S6), loaded into the container (2) by the advance of the stem (6) (step S7), and then extrusion is started.

  On the other hand, when the measured value by the temperature measuring device (10) is out of the proper temperature range for extrusion, particularly when the billet temperature is low, an alarm device is activated to warn the operator not to load the billet into the container. (In the case of NG in step S5). At the same time, the conveyance of the billet to the billet loader (5) is stopped, the billet (B) on the billet charger (7) is once removed, and is again subjected to the heating process by the billet heater.

  By the way, when the extruded material is a precision tube material such as a photosensitive drum base tube, an A3003 aluminum alloy is used as the material. Thus, when a predetermined pipe material is extruded using a billet made of the A3003 alloy, an appropriate billet temperature for use in extrusion, that is, an appropriate extrusion temperature is about 350 ° C. Within the range of ˜520 ° C. When a billet with a temperature deviating from this temperature range is subjected to extrusion, the general tendency is to cause coarsening of the crystal grain size and to cause unevenness in surface roughness and internal structure at the front and rear ends of the extruded material. Is seen. A more preferable extrusion suitable temperature range is 400 ° C to 500 ° C.

  The extrusion speed also has a significant effect on the quality of the surface properties and the like. The speed is preferably set in the range of 5 to 70 m / min. Even when processing at an extrusion speed outside this range, the general tendency of the coarsening of crystal grains on the surface becomes strong as described above, and it is difficult to obtain an extruded material of good quality over the entire length. A more preferable range of extrusion speed is 10 to 50 m / min.

<Experimental example>
Therefore, based on the knowledge of such empirical preferred extrusion processing conditions, in the state where the appropriate temperature range of the billet (B) immediately before being subjected to extrusion processing is set to 400 to 500 ° C. and the extrusion speed is 10 to 50 m / min, When an extruded tube material having a diameter of 20 mm was extruded using a billet made of an A3003 alloy by the extrusion apparatus and method according to the present invention, all of the obtained extruded materials had a surface crystal grain size of 250 μm or less. Thus, it was confirmed that the crystal grains did not have coarse crystal grains. Further, when the extruded material was subjected to a drawing process and an alumite treatment, and the surface properties were visually inspected, it was confirmed that none of the macroscopic patterns appeared and the internal structure was uniform. When the container was loaded, the billet that was to be avoided because the billet temperature deviated from the proper extrusion temperature was about 1% of the billet used.

It is explanatory drawing which shows the outline | summary of a structure of the extrusion processing apparatus which concerns on this invention in a planar state. It is a flowchart explaining the process from the heating of a billet to the loading of the container of an extruder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Extruder 2 ... Container 3 ... Dies 4 ... Die slide 5 ... Billet loader 6 ... Stem 7 ... Billet charger 10 ... Temperature measuring device 10a ... Thermocouple 11 ... Billet insertion control device B ... Billet

Claims (12)

Set the appropriate temperature range of billet temperature in the extrusion process conditions in advance,
Measure billet temperature just before the container is loaded with billet,
The measured value of the billet temperature is compared with the preset appropriate temperature range, and only when the measured temperature is within the appropriate temperature range, the billet is loaded into the container and the extruded material is extruded. Extrusion method characterized by performing.   The extrusion method according to claim 1, wherein the billet is a 3000 series aluminum alloy.   The extrusion method according to claim 1, wherein the extruded material is an aluminum tube material.   The extrusion method according to claim 2 or 3, wherein the extrusion processing is performed by setting the appropriate temperature range of the billet temperature to 350 to 520 ° C.   5. The extrusion method according to claim 1, wherein the billet temperature is measured at the front end in the extrusion direction of the billet mounted on the billet carrier after the heat treatment. .   The extrusion method according to claim 5, wherein the billet temperature is measured using a thermocouple.   The extrusion method according to any one of claims 2 to 6, wherein the extrusion processing is performed by setting the extrusion speed in a range of 5 to 70 m / min.   The extrusion method according to any one of claims 2 to 7, wherein the extruded material is a photosensitive drum base tube. A temperature measuring means for measuring the temperature of the billet after the heat treatment mounted on the billet charger;
Means for setting an appropriate temperature range of the billet temperature in the extrusion processing conditions;
Comparing the measured value of the billet temperature measured by the temperature measuring means with the appropriate temperature range, and loading the billet on the billet charger into the container only when the measured value is within the appropriate temperature range. An extrusion apparatus comprising drive control means for executing.   The extrusion processing apparatus according to claim 9, wherein the billet temperature measuring means measures the temperature of the front end portion in the extrusion direction of the billet mounted on the billet carrier.   11. The extrusion processing apparatus according to claim 10, wherein the temperature measuring means has a thermocouple installed so as to be able to advance and retreat with respect to the front end face of the billet on the billet carrier.   The extrusion processing apparatus according to any one of claims 9 to 11, further comprising alarm means for giving a warning not to load the billet into the container when the measured value of the billet temperature deviates from the appropriate temperature range.

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