JP7363632B2 - Container retreat control method for extrusion press equipment - Google Patents

Description

The present invention relates to a container retraction control method when a discard inside the container is exposed from the container after the extrusion process is completed in an extrusion press apparatus.

Referring to FIG. 1, a general extrusion press apparatus 100 and an extrusion process for extruding an extruded material made of aluminum or its alloy material will be described. FIG. 1 is a schematic plan view of an extrusion press apparatus 100, including a partial cross section. A main ram 12B driven by hydraulic pressure is arranged in the main cylinder 12A, and an extrusion stem 24 is attached to the tip of the main ram 12B via a main crosshead 22.

When extruding an extruded material (hereinafter referred to as a billet 20) using the extrusion press device 100, a container 18 (hereinafter referred to as a billet 20) is attached to a die 16 placed on the end platen 10 side via a pressure ring 10B using a container cylinder 28 by a holding means (not shown). The container holder 19) is pressed (container seal). Then, the main ram 12B is advanced to press the billet 20 housed in the container 18 against the die 16 by the extrusion stem 24 (upset step). The pressed billet 20 is plastically deformed so as to expand in the radial direction, and tightly adheres to the inner peripheral surface of the container 18. The upset process prepares the extrusion process.

By further advancing the main ram 12B, the billet 20 is pressed (pressing force) against the die 16 by the extrusion stem 24, and the extruded product 21 with a predetermined cross-sectional shape is continuous from the die 16 to the extrusion opening 10A. It is then extruded (extrusion process). In addition, in FIG. 1, the movement of the main ram 12B in the extrusion process is referred to as forward movement, and the left side of the extrusion press apparatus 100 in FIG. 1 is referred to as the front, and the right side is referred to as the rear. Further, the movement of the illustrated configuration toward the rear is referred to as backward movement.

On the other hand, the main cylinder 12A is arranged approximately at the center of the main cylinder housing 12 arranged to face the end platen 10, and has an oil chamber and a hydraulic oil tank (not shown) in the main cylinder 12A at its rear end. A prefill valve 12C is arranged to control opening and closing of the flow of hydraulic oil between the two. Further, a plurality of side cylinders 26 are arranged around the main cylinder 12A of the main cylinder housing 12. The cylinder rod of the side cylinder 26 is fixed to the rear end surface of the main crosshead 22, and is driven when the main ram 12B, which does not have a retreating means, retreats. Further, in the extrusion process, it is driven forward in synchronization with the advance of the main ram 12B (main crosshead 22).

The end platen 10 is connected to the main cylinder housing 12 by a tie rod nut 13 and a tie rod 14. The reaction force of the pressing force acts on the end platen 10 via the die 16 (pressure ring 10B) during the extrusion process, and acts on the main cylinder housing 12 via the main cylinder 12A, and is directed in a direction to separate them from each other. It acts on In response to the reaction force of such pressing force, there are tie rods 14 that pass through the four corners of the end platen 10 and the corresponding four corners of the main cylinder housing 12, and a tie rod 14 that is arranged at both ends of the tie rod 14 and constitutes a large diameter portion of the tie rod 14. The tie rod nut 13, which constitutes the large diameter portion of the tie rod 14, restrains the movement of the end platen 10 and the main cylinder housing 12 in the direction of separating them from each other. ) is configured to resist the reaction force of the pressing force.

In such an extrusion press apparatus 100, as a result of extruding the billet 20 shown in FIG. 1 from the die 16 as an extruded product 21, residues of the billet 20, so-called discards, remain in the container 18 after the extrusion process is completed. . The thickness of this discard is a set value that is set and input in advance to a control device (not shown). Furthermore, the stop position (extrusion completion position) of the main crosshead 22 at the completion of the extrusion process is controlled based on the thickness of the discard that is set and input.

Here, with reference to FIG. 2, the extrusion process, including the thickness of the discard (discard thickness D1) where the stop position (extrusion completion position) of the main crosshead 22 at the time of completion of the extrusion process is controlled, and related configurations. The dimensional relationship with the stop position of the main crosshead 22 at the time of completion (extrusion completion position/distance L1) will be explained. FIG. 2 is a close-up view of the container 18 of FIG. For the sake of explanation, illustration of the container 18 and its related components is omitted. The area below the center line in FIG. 2 shows a state in which there is no member deformation due to pressing force or reaction force. On the other hand, the area above the center line indicates a state in which the member is deformed due to the pressing force and its reaction force after the extrusion process is completed.

A position sensor moving body 41a of a main crosshead position sensor 41 (also called a linear displacement sensor, etc.) that measures the position of the main crosshead 22 in the extrusion press device 100 in real time is arranged on the side surface of the main crosshead 22. There is. The position sensor moving body 41a moves together with the position measurement target (main crosshead 22 in FIG. 2). Further, the position sensor main body 41b combined with the position sensor moving body 41a is arranged in a configuration that does not move in the extrusion press apparatus 100 (tie rod 14 in FIG. 2). The position sensor moving body 41a has a configuration in which it slides with respect to the position sensor main body 41b, and a configuration in which it does not come into contact with the position sensor main body 41b (non-contact configuration). The main crosshead position sensor 41 in FIG. 2 has the latter non-contact configuration (floating type).

The main crosshead position sensor 41 determines the relative position of the main crosshead 22 in the extrusion press device 100 in real time, for example, with the retraction limit position of the main crosshead 22 (right side in FIG. 2/not shown) as a reference position. The forward position from the reference position can be continuously monitored. In addition, the main cross head 22 in the extrusion process may be adjusted depending on various dimensions in the specifications of the extrusion press apparatus 100 that are stored in advance in the control device, such as the protrusion dimension of the die 16 from the end surface of the end platen 10 (thickness of the die 16). During the forward movement, it is possible to detect that the main crosshead 22 has reached a position at a distance L1 shown in FIG. The discard thickness D1 is a set value, and the extrusion stem length PS1, which is the length of the extrusion stem 24, and the distance S1 from the front end surface of the main crosshead 22 to the position sensor moving body 41a are fixed values according to the device specifications. These set values and fixed values are recorded in advance in the control device. As a result, as shown below the center line in FIG. 2, in a state where there is no member deformation, the following relational expression 1 holds true for these numerical values.
・Relational expression 1: L1=D1+PS1+S1
That is, the assumption is that when the main crosshead 22 stops advancing at the point when it has advanced to a distance L1 in the extrusion process (the extrusion process is completed), the thickness of the discard 20a in the container 18 is D1. It is.

In this manner, by setting and inputting the set value of the discard thickness D1, the stopping position (distance L1) of the main crosshead 22 at the time of completion of extrusion is calculated using the above-mentioned relational expression 1. Based on this calculated stop position of the main cross head 22, the stop position (extrusion completion position) of the main cross head 22 in the extrusion process is controlled.

However, during the extrusion process, the extrusion stem 24 is compressed and the tie rod 14 is expanded due to the reaction force of the pressing force applied to the billet 20 via the extrusion stem 24. Even when the extrusion process is completed, this state is maintained until the main cylinder pressure relief process, which will be described later, is started. Specifically, as shown above the center line of FIG. 2, when the extrusion process is completed, the length of the extruded stem 24 in the compressed state becomes the extruded stem length PS1', and the actual discard thickness D1' and the extruded A distance L1' indicating the actual position of the main crosshead 22, including the distance S1 which does not change during the process, is expressed by the following relational expression 2.
・Relational expression 2: L1'=D1'+PS1'+S1
In order to show that the extruded stem 24 is in a compressed state, the extruded stem 24 above the center line in FIG. 2 is illustrated with its center swollen like a drum.

Here, the compression amount of the extrusion stem 24 after the extrusion process is completed (before the main cylinder pressure release process) is the extrusion stem compression amount CP1, and the tie rod is based on the mounting position of the position sensor body 41b of the main crosshead position sensor 41. When the amount of extension of 14 is set as the amount of tie rod extension TE1, the following relational expressions 3 and 4 hold true.
・Relational expression 3: PS1=PS1'+CP1
・Relational expression 4: L1'=L1+TE1

In FIG. 2, the discard thicknesses D1 and D1' are shown as having the same thickness for easy viewing. However, from the above relational expressions 1 to 4, the relationship between the discard thicknesses D1 and D1' is expressed by the following relational expression 5.
・Relational expression 5: D1'=D1+CP1+TE1

That is, when the main cross head 22 is stopped based on the stop position (extrusion completion position/distance L1) of the main cross head 22 calculated based on the set discard thickness D1, the actual main cross head 22 Although the stop position is at a distance L1 when measured by the main crosshead position sensor 41, it is actually at a distance L1', and at that time, the thickness of the discard 20a actually remaining in the container 18 is D1' is larger (thicker) than the set discard thickness D1 by the sum of the extruded stem compression amount CP1 and the tie rod extension amount TE1.

Then, after the extrusion process is completed, when a main cylinder pressure release process as described below is performed, the extrusion press device 100 returns to a state where there is no member deformation due to the pressing force or reaction force. At this time, if the actual measured value of the distance L1 shown below the center line in FIG. Therefore, the following relational expression 6 is established.
・Relational expression 6: RL1=D1'+PS1+S1
By substituting the above relational expression 5 regarding D1' into the above relational expression 6 and eliminating D1', the distance RL1 in a state where there is no member deformation due to the pressing force or its reaction force is shown by the following relational expression 7. Become.
・Relational expression 7: RL1=(D1+CP1+TE1)+PS1+S1
This relational expression 7 is an important relational expression in the present invention, and will be described later.

Such a difference between the set discard thickness D1 and the actual discard thickness D1' is viewed as a problem in Patent Document 1, as it worsens the yield. Patent Document 1 solves this problem by determining the position of the main ram when the maximum pressing force is applied and the position when the main ram starts displacement with a dummy die set in advance. The main ram position and the main ram pressure at that time are measured. After the main ram pressure during the actual extrusion process reaches the main ram pressure at which the main ram is displaced, the maximum main ram displacement amount when the maximum pressing force is generated is divided by the proportion to the actual main ram pressure. Let be the displacement correction amount of the main ram position at the actual main ram pressure. Then, by controlling the position obtained by subtracting the displacement correction amount from the set discard thickness as the main ram stop position, the main ram stop position is set so that the actual discard thickness is approximately the same as the set discard thickness. It is something to control. Patent Document 1 states that during the extrusion process, the tie rod expands by about 0 to 5 mm, the stem (extruded stem) contracts by about 0 to 5 mm, and the actual discard thickness differs from the set discard thickness by the amount of extrusion force (pressing force). ) It is stated that the thickness varies (becomes thicker) by about 0 to 10 mm depending on the difference in thickness.

Next, a container retraction control method (container stripping operation) when exposing the discard inside the container from the container after the extrusion process is completed will be explained. After the extrusion process is completed, the discard 20a remaining in the container 18 is cut by the end face of the die 16 to separate the discard 20a from the extruded product 21 (shearing process). For this purpose, it is necessary to expose the discard 20a remaining in the container 18 from the container 18. At this time, in order to expose the discard 20a from the container 18 in a continuous state with the extruded product 21, both the retraction operation of the container 18 by the container cylinder 28 and the main cylinder depressurization process described later are controlled. . The retreating motion of the container 18 at this time may be referred to as a container stripping motion to distinguish it from other container retreating motions.

In a conventional container stripping operation, a container retraction distance is set based on a preset discard thickness D1. This will be explained with reference to FIG. FIG. 3 is an explanatory diagram of the container stripping operation near the container 18 in FIG. 1. FIG. 3(a) shows the main cylinder pressure release step after the extrusion step is completed, and FIG. 3(b) shows the time when the container stripping operation is completed. After the extrusion process is completed, the discard 20a remaining in the container 18 is held between the die 16 and the extrusion stem 24, and is continuous with the extrusion product 21. Further, the discard 20a is plastically deformed so as to expand in the radial direction, and is in close contact with the inner circumferential surface of the container 18.

After the extrusion process is completed, the pressure of the hydraulic fluid in the main cylinder 12A is started to be reduced. This pressure reduction is called a main cylinder pressure relief process. In this main cylinder pressure release process, while the prefill valve 12C is closed, a pressure reducing valve (not shown) (sometimes referred to as a decon valve, etc.) is opened to reduce the internal pressure of the main cylinder 12A to the pressure immediately after extrusion is completed. Gradually reduce the pressure.

Here, the prefill valve 12C is an on-off valve disposed at a connection part of the oil chamber in the main cylinder 12A with a conduit (not shown) to a hydraulic oil tank (not shown). During the extrusion process, the prefill valve 12C is closed to prevent the hydraulic oil in the oil chamber in the main cylinder 12A from returning to the hydraulic oil tank, and to maintain the pressure in the oil chamber. When retracting the main crosshead 22 (main ram 12B) to the retraction limit position using the side cylinder 26 in a process other than the extrusion process (such as an idle process described later), the main crosshead 22 is prevented from being subjected to retraction resistance. The prefill valve 12C is then opened to enable discharge (flow) of a large amount of hydraulic oil into the hydraulic oil tank. Since such a prefill valve 12C is a well-known on-off valve in an extrusion press device, detailed explanation and illustration thereof will be omitted.

Then, when the hydraulic oil pressure in the main cylinder 12A is sufficiently reduced, the pressure reducing valve is closed, and the main cylinder pressure relief process is completed. When the pressure reduction is completed, the pressure inside the main cylinder 12A becomes substantially atmospheric pressure, but since the prefill valve 12C is closed, the oil chamber inside the main cylinder 12A remains filled with hydraulic oil. There is.

The control that does not open the prefill valve 12C even after the main cylinder pressure relief process is completed is such that the discard 20a that is in close contact with the inner circumferential surface of the container 18 as the container 18 retreats during the container strip operation. This is done to prevent the container from moving together with the container 18 (moving along with it). When such movement of the discard 20a with the container 18 occurs, the extruded product 21 and the discard 20a break at an unintended portion. In this case, not only the usable length of the extruded product 21 as a product decreases and the yield rate of the extruded product 21 decreases, but also the large shock generated at the time of breakage becomes an impact force, and the structural members of the extrusion press device 100 and the sliding adversely affect the part. Furthermore, because the discard 20a is held in the container 18 without being exposed from the container 18 due to the accompanying movement, the shearing process that will be performed later cannot be performed, and the container 18 is moved forward and backward to remove the discard 20a from the container 18. A step of extruding and removing the discard 20a by the extrusion stem 24 is required, which significantly reduces production efficiency.

Even if the main cylinder pressure release process is completed, the oil chamber in the main cylinder 12A is filled with hydraulic oil due to the control that does not open the prefill valve 12C, and the extrusion stem 24 (main crosshead 22 and main ram 12B) is not retreated. suppressed. Therefore, even if the retreating force of the container 18 acts on the extrusion stem 24 (main crosshead 22 and main ram 12B) via the discard 20a that is in close contact with the inner peripheral surface of the container 18, as shown in FIG. During the container stripping operation, a reaction force f is generated from the extrusion stem 24 to the discard 20a in accordance with the contact area of the discard 20a to the inner peripheral surface of the container 18. This reaction force f can prevent the discard 20a from moving together with the container 18.

From the state shown in FIG. 3(a), the container 18 (container holder 19) is moved back by the container cylinder 28 as shown in FIG. 3(b) without opening the prefill valve 12C. In this container stripping operation, the container retracting force CF applied to the container 18 by the container cylinder 28 is referred to as a container stripping force, and the retracting speed of the container 18 is referred to as a container stripping speed. The above container stripping force requires a large force for the idle process because the discard 20a is in close contact with the inner circumferential surface of the container 18, and the above container stripping speed does not allow the extruded product to reach unintended parts. In order to prevent the discard 21 and the discard 20a from breaking, the speed must be kept low relative to the idle process. The idle process is a process for moving various components to predetermined positions using various hydraulic drive means, and refers to all processes other than the extrusion process.

In view of the fact that the actual discard thickness D1' is larger (thicker) than the set discard thickness D1, in the conventional container retraction control method in the container stripping operation, the container The retreat distance of No. 18 is set to be longer. This is because when the set discard thickness D1 is set as the retraction distance of the container 18, the container retraction distance is insufficient and a portion of the discard 20a remains inside the container 18. When the main crosshead 22 and the container 18 (container holder 19) are moved back to the idle process for the next extrusion process while a part of the discard 20a remains in the container 18, the discard 20a remains in the container 18. The card 20a may move with the container 18, causing the problems described above.

For example, for conventional container retraction control in container stripping operation, the minimum value of the container retraction distance in container stripping operation is stored in advance as a fixed value in the control device. The discard thickness D1 is compared with the fixed value, and if the discard thickness D1 is sufficiently smaller, the fixed numerical value is automatically set as the container retreat distance. On the other hand, if the discard thickness D1 is not sufficiently smaller than the fixed value, or if it is larger than the fixed value, the value obtained by adding the set discard thickness D1 to the fixed value is automatically set as the container retreat distance. Set.

Here, the retreating distance of the container 18 in the container stripping operation from the position of the container 18 shown in FIG. 3(a) to the position of the container 18 shown in FIG. 3(b) is set in advance to make the diagram easier to understand. The thickness of the discard is D1. However, since the retreat distance of the container 18 is set to be longer than the set discard thickness D1, the container 18 will retreat further backward than in FIG. 3(b), although it is not shown. Become.

Japanese Patent Application Publication No. 04-322815

Originally, in the container retreat control method in the container stripping operation, as shown in FIG. 3(b), the actual discard thickness of the discard 20a remaining in the container 18 (discard thickness D1 in FIG. 3(b)) Ideally, the container 18 would be retracted by a distance equal to . In this way, the discard 20a will surely be exposed from the container 18, and will not be moved together with the container 18 even when the idle process is started.

However, as explained above, in view of the fact that the actual discard thickness D1' is larger (thicker) than the set discard thickness D1, the conventional container retraction control method in the container stripping operation The retraction distance of the container 18 is always set to be longer than the card thickness D1. Furthermore, the container retraction speed (container stripping speed) during container stripping operation must be lower than the idle process. In this way, since the container 18 is retreated at a low speed and by a distance longer than originally required, there is a problem in that the time required for the container stripping operation increases accordingly.

On the other hand, in order to solve the above problem, if the actual thickness D1' of the discard 20a remaining in the container 18 after the extrusion process is completed can be set as the container retraction distance, the discard 20a will move together with the container 18. It is possible to shorten the time required for the container stripping operation while preventing such problems.

To this end, it is conceivable to calculate the actual discard thickness D1' of the discard 20a remaining in the container 18 after the extrusion process is completed by utilizing the correction of the main ram position described in Patent Document 1. However, the correction of the main ram position described in Patent Document 1 is based on the extrusion press obtained by applying the maximum pressing force using a dummy die or a corresponding extrusion stem when the extrusion press device is completed. The maximum displacement amount of the device itself is proportionally divided by the actual pressing force to obtain the displacement correction amount when the actual pressing force is applied. In other words, this maximum displacement reflects the compression of the actual die and extrusion stem used in the extrusion process or replaced for each extruded product, and the actual pressing force generated in the actual extrusion process. It's not something that was done. Furthermore, changes in the maximum displacement of the extrusion press itself due to aging of the extrusion press are not reflected. In view of these, doubts remain about the accuracy of the actual discard thickness D1' of the discard 20a remaining in the container 18, which was calculated using the main ram position correction described in Patent Document 1.

The present invention was made in view of the above-mentioned problems, and calculates the thickness of the discards remaining in the container after the extrusion process is completed, and based on the thickness of the discards remaining in the container, the thickness of the discards remaining in the container is calculated. It is an object of the present invention to provide a method for controlling the retraction of a container in an extrusion press device that exposes the container from the container.

The above-mentioned object of the present invention is to include a position measurement step of measuring the main crosshead position when the main cylinder internal pressure drops to a preset position measurement pressure in the main cylinder pressure release step after completion of the extrusion step;
a discard thickness calculation step of calculating the thickness of the discard sandwiched between the die and the extrusion stem in the container from the main crosshead position measured in the position measurement step;
a container retreat distance setting step of setting the discard thickness calculated in the discard thickness calculation step as a container retreat distance;
Equipped with
After the main cylinder pressure relief step is completed, the container is moved from the container reference position with the on-off valve disposed at the connection part of the oil chamber in the main cylinder to the pipe line to the hydraulic oil tank closed. This is achieved by a container retraction control method for an extrusion press apparatus, characterized in that the container is retracted by a retraction distance to expose the discard from the container.

Further, in the container retreat control method for an extrusion press apparatus according to the present invention, in the position measuring step, the container position is further measured and the measured container position is set as the actual container position, and
Preferably, the actual container position is set as the container reference position and the container is retreated.

Furthermore, in the container retreat control method for an extrusion press apparatus according to the present invention, when the die is replaced, the actual container position measured in the first position measurement step after replacement is set as the actual container reference position. However, the method may further include a container position monitoring step of calculating a difference between the actual container reference position and the actual container position and issuing an alarm when the difference is larger than a preset tolerance value. .

The container retreat control method for an extrusion press device according to the present invention measures the main crosshead position when the main cylinder internal pressure drops to a preset position measurement pressure in the main cylinder pressure relief process after the extrusion process is completed. a position measurement process,
a discard thickness calculation step of calculating the thickness of the discard sandwiched between the die and the extrusion stem in the container from the main crosshead position measured in the position measurement step;
a container retreat distance setting step of setting the discard thickness calculated in the discard thickness calculation step as a container retreat distance;
Equipped with
After the main cylinder pressure relief step is completed, the container is moved from the container reference position with the on-off valve disposed at the connection part of the oil chamber in the main cylinder to the pipe line to the hydraulic oil tank closed. Since the discards are exposed from the container by retreating the distance, the thickness of the discards remaining in the container after the extrusion process is completed is calculated, and based on the thickness of the discards remaining in the container, the discards remaining in the container are removed from the container. It can be exposed from

FIG. 2 is a schematic plan view of the extrusion press apparatus, including a partial cross section. 2 is a close-up view of the container 18 in FIG. 1. FIG. FIG. 2 is an explanatory diagram of the container stripping operation in the vicinity of the container 18 in FIG. 1; 1 is a schematic flowchart of a container retreat control method for an extrusion press apparatus according to the present invention. It shows the vicinity of the container 18 in FIG. 1 and shows the start state of the container stripping operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the inventions claimed in each claim, and not all combinations of features described in the embodiments are essential to the solution of the invention. .

[First embodiment]
A container retreat control method for an extrusion press apparatus according to the first embodiment will be described with reference to FIG. 4. FIG. 4 is a schematic flowchart of a container retreat control method for an extrusion press apparatus according to the present invention. Each flow (step) described is electrically processed within the control device, between the control device and the detection means, between the control device and the drive means, or the like. Furthermore, since this is a schematic flowchart that lists flows necessary for explanation, it does not list all flows in actual control. Since the device configuration and the like necessary for the explanation have already been provided, reference will be made to FIGS. 1 to 3 as necessary, and the description of the device configuration and the like that has already been provided will be omitted.

After the extrusion process in the state shown above the center line in FIG. 2 is completed, the pressure reducing valve is opened and the main cylinder pressure relief process is started (ST1). While the pressure of the hydraulic oil in the main cylinder 12A is reduced and the pressure in the main cylinder 12A is gradually reduced, the control device detects the pressure in the main cylinder 12A using a pressure detection means (not shown) such as a pressure pickup. The pressure inside the main cylinder 12A is monitored until it drops to the preset position measurement pressure P1 (ST2).

At the timing when the internal pressure of the main cylinder 12A drops to a preset position measurement pressure P1, the position (distance RL1) of the main crosshead 22 is measured by the main crosshead position sensor 41 (ST3/position measurement step). During this time, the main cylinder pressure relief process continues, and when the internal pressure of the main cylinder 12A is reduced to substantially atmospheric pressure, the main cylinder pressure relief process is completed. As explained above, the distance RL1 in a state where there is no member deformation due to the pressing force or its reaction force is expressed by the following relational expression 7.
・Relational expression 7: RL1=(D1+CP1+TE1)+PS1+S1
Note that although FIG. 4 also shows a flow from ST10 to ST13 (indicated by a broken line) that branches from ST2, these flows are not essential flows in the first embodiment, so the explanation here will be omitted. Omit.

The position measurement pressure P1 is applied to ensure that the die 16 is in close contact with the extrusion direction by pressing the extrusion stem 24 through the discard 20a on the die 16, which is composed of a plurality of members stacked on top of each other in the extrusion direction. This is the internal pressure of the main cylinder 12A, and is the pressure for accurately measuring the position of the main crosshead 22, which is affected by the position of the tip of the extrusion stem 24, in the position measurement step (ST3). When the main cylinder pressure release process is completed, the pressure inside the main cylinder 12A is reduced to substantially atmospheric pressure, and the thickness of the die 16 in the extrusion direction, which is formed by overlapping a plurality of members in the extrusion direction, may change. Therefore, a predetermined pressure before the completion of the main cylinder pressure relief process is set in advance. Note that in the position measurement step (ST3), the push-out stem 24 is not compressed or the tie rod 14 is not extended due to the pressing force exerted by the push-out stem 24 that is generated due to the position-measurement pressure P1. Further, the configuration of the dice 16 will be described later.

Here, in the above relational expression 7, all values other than the extruded stem compression amount CP1 and the tie rod extension amount TE1 are set values (D1) or fixed values according to specifications (PS1, S1). Therefore, based on the distance RL1 measured by the main crosshead position sensor 41, the sum of the extruded stem compression amount CP1 and the tie rod extension amount TE1, that is, CP1+TE1, is calculated from the relational expression 7 as shown in the following relational expression 7'. In addition, it can be calculated without performing deformation analysis due to stress.
・Relational expression 7': CP1+TE1=RL1-D1-PS1-S1

Then, by substituting the right side of relational expression 7' into CP1+TE1 of relational expression 5 (D1'=D1+CP1+TE1) which shows the relationship between the actual discard thickness D1' and the set discard thickness D1, the actual discard thickness D1' is expressed by the following relational expression 8.
・Relational expression 8: D1'=RL1-PS1-S1

In this way, the actual discard thickness D1' is calculated (ST4/discard thickness calculation step). RL1 is a measured value, and the extrusion stem length PS1 and distance S1 (distance from the front end surface of the main crosshead 22 to the position sensor moving body 41a) are fixed values according to the specifications, so the discard thickness D1 is based on relational expression 8. ' is easy to calculate. In addition, since it is calculated based on the position of the main crosshead 22 measured in a state where there is no member deformation due to pressing force or its reaction force, the calculated discard thickness D1' is based on the main crosshead described in Patent Document 1. It is easy to imagine that the accuracy is higher than the actual thickness of the discard 20a calculated using correction of the ram position.

Next, the calculated discard thickness D1' is set as the container retreat distance CB1 (ST5/container retreat distance setting step). Based on this container retraction distance CB1, a retraction command for the container 18 (container holder 19) is sent to the container cylinder 28, related hydraulic equipment in the hydraulic circuit is controlled, and the retraction operation of the container 18 is started (ST7). At this time, the main cylinder pressure relief process has been completed, and the pressure inside the main cylinder 12A has been reduced to substantially atmospheric pressure, and the pressure reducing valve is maintained in an open state. It is preferable that the retreating operation of the container 18 is started (ST7) after confirming completion of pressure reduction in the main cylinder pressure relief step (ST6) by monitoring the internal pressure. Further, the retraction speed (container stripping speed) of the container 18 is set and inputted in advance, or is automatically set to a numerical value appropriately calculated within the control device according to the set discard thickness D1.

Here, measurement of the position of the container 18 will be explained with reference to FIG. FIG. 5 shows the vicinity of the container 18 in FIG. 1 at the start of the container stripping operation. The area below the center line in FIG. 5 shows a state in which the die 16 has not been deformed due to aging or the like. On the other hand, the upper part shows a state in which the die 16 has been deformed due to aging, etc., which will be described later.

The position of the container 18 (container holder 19) in the extrusion press apparatus 100 is measured in real time by the container position sensor 61. The container position sensor 61 employs the same type of position detection means as the main crosshead position sensor 41, and the position sensor moving body 61a of the container position sensor 61 is arranged on the side surface of the container holder 19. Note that in FIG. 5, the container holder 19 is not shown for the sake of clarity, so the position sensor moving body 61a is shown on the side of the container 18. A position sensor main body portion 61b that is combined with the position sensor moving body 61a is arranged on the tie rod 14. The position sensor body part 61b (FIG. 5) of the container position sensor 61 partially overlaps the position sensor body part 41b (FIG. 2) of the main crosshead position sensor 41 in that it is disposed on the tie rod 14. However, since the tie rods 14 are arranged at the other four corners of the end platen 10 (four pieces), each position sensor main body may be arranged on a different tie rod 14.

Here, the container retreat start position when the container 18 starts to retreat (ST7) is determined by pressing the container 18 against the die 16 with a predetermined pressure by the container cylinder 28, such as when replacing the die 16. The container reference position CT1 (fixed value) is recorded in the control device in association with the dice 16 as the position of the state measured by the container position sensor 61.

In FIGS. 1 to 3 and 5, the die 16 is shown as an integral structure for clarity. However, in reality, a member with an opening that mimics the cross-sectional shape of an extruded product, or multiple members made of different shapes and materials for the purpose of receiving pressure, etc., are stacked in the extrusion direction and placed in a die stack, etc. arranged and configured as a die 16 for each extruded product. Therefore, when the die 16 is replaced, or even when the same die 16 is combined with another member other than the member having an opening hole that imitates the cross-sectional shape of the extruded product, the container cylinder 28 The container reference position CT1 is reset by pressing the container 18 against the die 16 with this pressure.

In the control device, a container retreat distance CB1 (=discard thickness D1') is set with this container reference position CT1 (fixed value) as a starting point (ST5), and after the container 18 starts retreating (ST7), the container 18 retreats. The distance is monitored (ST8). When the container position sensor 61 detects that the container 18 has retreated by the container retreat distance CB1, the container retreat control in the container stripping operation is completed and the process shifts to an idle process. At the time of transition to the idle stage, the prefill valve 12C is opened, and the container 18 continues to retreat from the container stripping operation, although the speed increases. Then, in synchronization with the retreat of the container 18, the main crosshead 22 (extrusion stem 24, main ram 12B) starts to retreat by the side cylinder 26.

By the container retraction control method of the extrusion press apparatus according to the first embodiment as described above, the actual thickness of the discard 20a remaining in the container 18 after the completion of the extrusion process (discard thickness D1') is Regardless of the set discard thickness D1, it is accurately calculated based on the position of the main crosshead 22 measured in a state where there is no member deformation due to pressing force or reaction force. Then, the calculated actual discard thickness D1' is automatically set as the container retraction distance CB1 in the container stripping operation. As a result, even if the container retraction speed during the container stripping operation is an appropriately low speed at which the discard 20a does not move along with the container 18, there is no need to retreat the container 18 beyond the originally necessary distance, and the container stripping operation The required time can be shortened.

Although the first embodiment has been described above as the mode for carrying out the invention, the present invention is not limited to the above embodiment, and the present invention can be implemented without departing from the scope of the claims. Needless to say, this can be implemented in a variety of ways.

As described above, the die 16 has a structure in which a plurality of members made of different shapes and materials are stacked on each other in the extrusion direction. Therefore, the extrusion process is repeated and the pressure history of the pressing force (pressing force x working time) is accumulated, and for example, the die thickness DE1 of the die 16 changes upward from the state shown below from the center line in FIG. The die thickness gradually decreases to the state shown in FIG.

Therefore, even in the extrusion process using the same die 16, the container position when the container cylinder 28 presses the container 18 against the die 16 with a predetermined pressure, that is, the container reference position CT1, may change due to changes over time. There is a risk of change. Assume that the die thickness DE1 of the die 16 is reduced by the die compression amount CPD1 to the die thickness DE1'. In this case, although the container 18 is actually retracted from the container position corresponding to the die thickness DE1' shown above, the container retraction distance CB1 (=discard thickness D1') is the same as the center line in FIG. The container reference position CT1 shown further below is set as the starting point.

As a result, the container retreat distance with respect to the discard thickness D1' of the discard 20a pressed by the die thickness DE1' upward from the center line in FIG. 5 is as follows: In other words, the container is moved back by the die compression amount CPD1, and from there, the container is moved back by a distance CB1 (=discard thickness D1'). The retreat distance is calculated as D1'+CPD1, and the container 18 completes retreating position is at a position where the discard 20a is completely exposed from inside the container 18 and is further retreated by an additional die compression amount CPD. Become.

Even in such a situation, the starting point of the container retraction distance CB1 in the container retraction distance setting step (ST5) is not the container reference position CT1 (fixed value) but the position of the main crosshead 22, which is the same as the position of the main crosshead 22. In the position measurement process in which there is no member deformation due to force or its reaction force, by using the actual position of the container 18 measured by the container position sensor 61, it is possible to reliably move the discard 20a from the container 18 to the actual discard thickness D1. It can be exposed for only 'minutes.

In this case, the flow from ST10 to ST13, which is not explained in the first embodiment and is shown on the right side of FIG. (indicated by a broken line) can be selected. This option has two flows.

First, the first flow will be explained. This is called another form 1. At the timing (ST2) when the internal pressure of the main cylinder 12A drops to the position measurement pressure P1, the main crosshead position sensor 41 measures the position (distance RL1) of the main crosshead 22 (ST3), and the container position sensor 61, the position of the container 18 (container holder 19) is measured (ST10). The position of this container 18 is defined as a real container position RCT1. In Alternative Embodiment 1 and Alternative Embodiment 2, which will be described later, both the flows of ST3 and ST10 are position measurement steps. That is, in alternative embodiments 1 and 2, the actual container position RCT1 is measured each time the position measurement step is performed.

Then, the actual container position RCT1 measured in ST10 is stored in the control device, and in the container retreating distance setting step (ST5), the actual container position RCT1 is set as the starting point of the container retreating distance CB1, instead of the container reference position CT1 explained earlier. , the container retreat distance CB1 is set. In this way, since the container retraction distance CB1 (discard thickness D1') is set each time using the actual container position (actual container position RCT1) in the position measurement process after the completion of the extrusion process as the starting point, the distance shown in FIG. Even in a situation where the actual position of the container 18 (container retraction start position) changes due to changes in the thickness of the die 16 as shown above the center line, the die 16 can be reliably moved to the discard thickness D1. ' can be exposed from the container 18. As a result, there is no need for unnecessary retreat by the die compression amount CPD1, and the time required for the container stripping operation can be shortened.

Next, the second flow will be explained. This is called another form 2. The point at which the container retreat distance CB1 (discard thickness D1') is set (ST5) using the actual container position (actual container position RCT1) in the position measurement step (ST10) as the starting point each time is the point where This is the same as Embodiment 1, but differs from Embodiment 1 in that it goes through the flow from ST10 to ST11, ST12, and ST13, as enclosed by a two-dot chain line.

In another embodiment 2, the actual container position RCT1 measured in ST10 is compared with the actual container reference position CT2 (ST11). The actual container reference position CT2 is the container in the main cylinder depressurization process after the completion of the first extrusion process after the replacement, when the die 16 is replaced, or when some parts of the same die 16 are replaced. This is the actual container position RCT1 measured in the No. 18 position measurement step (ST10). Although it is considered that there is no major difference from the container reference position CT1, it is treated as a different container position (value) in the present invention.

Then, as described above, the actual container reference position CT2 is set when the die 16 is replaced, or even when some parts of the same die 16 are replaced, and then the position measurement step (ST10) is performed. If the difference from the actual container position RCT1 measured in is smaller than the preset tolerance value, in the container retreat distance setting step (ST5), the container retreat distance is set with the starting point of the container retreat distance CB1 as the actual container position RCT1. Set CB1.

On the other hand, if the difference between the actual container reference position CT2 and the actual container position RCT1 is larger than the allowable value, an alarm is issued (ST13). As a result, controls such as generating an alarm sound or displaying an alarm on the display means or display screen of the control device or operation panel are performed. In the same flow, only an alarm is issued, and in the container retreat distance setting step (ST5), the container retreat distance CB1 is set with the starting point of the container retreat distance CB1 as the actual container position RCT1, but if necessary, After completion of the idle process, control may be performed to stop the operation of the extrusion press apparatus 100 without proceeding to the next extrusion process.

In alternative form 2, as in alternative form 1, even if the actual position of the container 18 (container retreat start position) changes due to changes in the thickness of the die 16, etc., the die 16 can be reliably moved. By exposing the discard thickness D1' from the container 18, unnecessary retreat by the die compression amount CPD1 is unnecessary, and the time required for the container stripping operation can be shortened. Furthermore, although it depends on the preset tolerance value, due to the alarm being issued, the position of the container 18 (container retreat start position) in the position measurement step (ST10) may be different from the previous container stripping operation for some reason. You can see that things are changing. Such a change in the position of the container 18 is considered to be caused by the compressive deformation of the die 16 as described above.

In addition, in the shearing process, aluminum scum from the cut discard 20a may adhere to the end face of the die 16, and during the extrusion process, aluminum scum protruding from the container sealing surface between the die 16 and the container 18 may adhere to the end face of the die 16 or Another possible cause is that aluminum scum is stuck between the die 16 and the container 18 due to adhesion to the sealing surface of the container 18 on the die 16 side.

In alternative form 2, for example, while setting a relatively large tolerance value for the former, the comparison (ST11/ST12) between the actual container reference position CT2 and the actual container position RCT1 is not performed every time in the extrusion process. In an extrusion process in which the same die 16 is continuously used, the die 16 is replaced every time a preset number of extrusion processes are completed, mainly taking into account changes over time and the pressure history of the pressing force. It may be used as a guideline. Alternatively, while setting a plurality of relatively small tolerance values for the latter, a comparison (ST11/ST12) between the actual container reference position CT2 and the actual container position RCT1 is performed with the differences displayed each time in the extrusion process. , it is possible to make it possible for the operator to know which tolerance value the alarm is being issued due to the difference being larger, and to use it mainly for determining the state of aluminum scum being caught between the die 16 and the container 18. good.

10 End platen, 10A Extrusion opening, 10B Pressure ring, 12 Main cylinder housing, 12A Main cylinder, 12B Main ram, 12C Prefill valve, 13 Tie rod nut, 14 Tie rod, 16 Die, 18 Container, 19 Container holder, 20 billet, 20a discard, 21 extruded product, 22 main crosshead, 24 extruded stem, 26 side cylinder, 28 container cylinder, 41 position sensor for main crosshead, 41a position sensor moving body, 41b position sensor main body, 61 for container position sensor, 61a position sensor moving body, 61b position sensor main body, 100 extrusion press device,
CB1 Container retraction distance, CF Container retraction force, CP1 Extrusion stem compression amount, CPD1 Die compression amount, CT1 Container reference position, CT2 Actual container reference position, D1/D1' Discard thickness, DE1/DE1' Die thickness, f Reaction force , L1/L1'/RL1/S1 distance, P1 position measurement pressure, PS1/PS1' extruded stem length, RCT1 actual container position, TE1 tie rod extension amount

Claims (1)

a position measurement step of measuring the main crosshead position when the main cylinder internal pressure drops to a preset position measurement pressure in the main cylinder pressure relief step after the extrusion step is completed;
a discard thickness calculation step of calculating the thickness of the discard sandwiched between the die and the extrusion stem in the container from the main crosshead position measured in the position measurement step;
a container retreat distance setting step of setting the discard thickness calculated in the discard thickness calculation step as a container retreat distance;
Equipped with
After the main cylinder pressure relief step is completed, the container is moved from the container reference position with the on-off valve disposed at the connection part of the oil chamber in the main cylinder to the pipe line to the hydraulic oil tank closed. retracting a retraction distance to expose the discard from the container ;
In the position measurement step, further measuring the container position and setting the measured container position as the actual container position,
retreating the container using the actual container position as the container reference position;
When the die is replaced, the actual container position measured in the first position measurement step after replacement is set as the actual container reference position, and thereafter, the difference between the actual container reference position and the actual container position is calculated. A container retreat control method for an extrusion press apparatus, further comprising a container position monitoring step of calculating the difference and issuing an alarm when the difference is larger than a preset tolerance value.

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