JP2015217391A - Extrusion press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems of causing reduction in productivity when a delay is caused in extrusion rise-up time when the relationship between pressure and a leakage oil quantity changes by this, though a relief valve conventionally gradually causes wear such as a poppet and a sheet surface by a secular change, and of continuing operation without being conscious of the reduction in productivity due to being difficult to grasp the pressure and the leakage oil quantity in production operation for an operator.SOLUTION: An extrusion press comprises movement means of a container, and molds a section by extruding a billet loaded in the container by a main cylinder device from a die by an extrusion stem, and a change in a characteristic by a secular change in a relief valve is measured in ordinary production operation, and the measured characteristic is graphed, and a control parameter in extrusion ris-up time is automatically changed in response to a level of a characteristic change.

Description

  The present invention relates to relief characteristic measurement and extrusion start-up control parameter change in an extrusion press.

In general, when a billet made of a metal material such as aluminum or an alloy material thereof is extruded by an extrusion press device, an extrusion stem is attached to the tip of a main ram driven by a hydraulic cylinder, and a container is pressed against a die. Then, the billet is stored in the container with an extrusion stem or the like. Then, the billet is pressed by the extrusion stem by further advancing the main ram by driving the hydraulic cylinder. Therefore, the molded product is extruded from the outlet of the die.

The drive source of the extrusion press is hydraulic, and the hydraulic parts play an important role in driving the extrusion press. Further, since the working pressure of the pressure oil in the extrusion press is as high as 30 MPa, for example, the durability of the hydraulic parts is an important factor for productivity.
However, in reality, the wear of hydraulic parts is so severe that the maintenance and replacement of the hydraulic parts are frequently performed. For this reason, even if there is a deterioration of the hydraulic component, the deterioration gradually proceeds, so it is often used as it is. For this reason, the rise time of extrusion is delayed and productivity is often lowered.
Among hydraulic components, the relief valve plays an important role in setting the oil pressure of the entire extrusion press. In addition, since the relief valve is expensive, it cannot be frequently replaced and is often used as it is even if the deterioration progresses.

JP 2011-1111796 A

The relief valve gradually wears poppets, seat surfaces, etc. over time, but this changes the relationship between the pressure and the amount of leaked oil, causing a delay at the start of extrusion and reducing productivity. Further, since it is difficult for the operator to grasp the pressure and the amount of leaked oil during the production operation, the operation is continued without noticing the decrease in productivity.
Therefore, even if the characteristics of the relief valve change, the control parameters at the time of extrusion start-up are the same. Therefore, the rise time of extrusion is delayed, and it is unavoidable even if productivity decreases.

In an extrusion press comprising a container moving means, and a billet loaded in the container by a main cylinder device is extruded from a die by an extrusion stem to form a profile,
Changes in characteristics due to aging of the relief valve were measured in normal production operation, and the measured characteristics were graphed, and the control parameters at the start of extrusion were automatically changed according to the level of characteristic change.

  The change from the initial state was visualized and the maintenance time was warned.

The characteristic of the pressure-leakage oil amount of the relief valve is automatically measured during normal production operation from the pump discharge command, pressure and actual speed at the start-up control at the initial stage of extrusion. In general, a pressure mold is set, and pressure is manually applied, and the characteristics are measured by the relationship between the discharge amount and pressure, the pressure rise time measurement, and the like.
By displaying the measured characteristics in a graph on a touch panel or the like, it is possible to visually convey the deterioration of the relief valve to the operator or the like.
By changing the control parameters at the start-up according to the degree of deterioration of the measured characteristics divided in advance, the pump discharge rate is increased to compensate for the amount of leaked oil, and even if deterioration progresses Production can be continued without significantly reducing productivity.
For this reason, an expensive relief valve can be used to the limit, it is not necessary to replace frequently, and cost reduction can be realized.
Also, frequent maintenance can be omitted.

1 is an overall schematic view of an extrusion press according to the present invention. It is a figure of the flow-pressure characteristic of an initial relief valve, and the relationship between general extrusion pressure and speed. It is a figure of the flow rate-pressure characteristic of the relief valve in the early stage of deterioration, and the relationship between general extrusion pressure and speed. It is a figure of the flow rate-pressure characteristic of the relief valve of the latter stage of deterioration, and the general relationship between extrusion pressure and speed. It is a figure of a relief valve characteristic measuring method. Relief valve characteristic diagram obtained by characteristic measurement method It is a figure which shows the image of the threshold value of the characteristic obtained with the characteristic measuring method of the relief valve. In order to supplement the amount of leakage, the pressure oil set value (discharge amount) is increased linearly with time.

  The characteristic measurement of the relief valve of the extrusion press and the change of the extrusion start-up control parameter according to the present invention will be described in detail below with reference to the drawings.

First, the outline of the extrusion press of the present invention will be described with reference to FIG.
As shown in FIG. 1, in an extrusion press used in the present invention, an end platen 1 and a main cylinder 2 are arranged facing each other, and both are connected by a plurality of tie rods 3. A container 5 is disposed on the inner side surface of the end platen 1 with a die 4 formed with an extrusion hole interposed therebetween. A billet 6 is loaded into the container 5 and is extruded and pressed toward the die 4 to form a die hole. An extruded material having a corresponding cross section is extruded.

  The main cylinder 2 that generates the pushing action force has a built-in main ram 9 that can be pressurized and moved toward the container 5. At the front end portion of the main ram 9, the extrusion stem 7 is in close contact with a billet loading hole of the container 5, and a dummy block (not shown) is brought into close contact with the front end of the main ram 9 so as to protrude toward the container 5. 8 is attached. Therefore, when the main cylinder 2 is driven and the main cross head 8 is moved forward, the extrusion stem 7 is inserted into the billet loading hole of the container 5 and the rear end surface of the loaded billet 6 is pressurized to push the extruded material. is there.

  A plurality of side cylinders 10 are attached to the main cylinder 2 in parallel with the extrusion axis, and the cylinder rods 11 are connected to the main cross head 8. As a result, the extrusion stem 7 is initially moved to a position close to the container 5 as a preparation step of the extrusion step, and the extrusion pressure operation is performed using both the main cylinder 2 and the side cylinder 10.

  First, the flow rate and pressure characteristics of the relief valve of the extrusion press and the changes in extrusion pressure and speed due to aging are shown first.

FIG. 2 shows the flow rate-pressure characteristics of the initial relief valve and the general relationship between extrusion pressure and speed.
As the oil pressure increases, the relief valve starts to leak near the set value. When the pressure rises further than this pressure, the amount of leaked oil gradually increases, and when the set pressure is reached, the oil is blown at once. Thereafter, when the oil pressure value starts to decrease, the leakage amount also decreases. When the pressure value at which oil starts to leak first is reached, the leakage amount becomes zero.
In the case of an early relief valve, the characteristics of flow rate and pressure appear in a very sharp form.
Further, when the extrusion pressure is indicated by a solid line and the speed curve is indicated by a broken line in FIG. 2B, the relationship between the extrusion pressure and the speed of the main ram 9 is that the main ram speed rises quickly and the extrusion pressure rises quickly. The predetermined set speed is well reached.

FIG. 3 shows the flow rate-pressure characteristics of the relief valve at the initial stage of deterioration, and the general relationship between extrusion pressure and speed.
As the oil pressure increases, oil begins to leak, but begins to leak at a lower pressure than the initial relief valve. Also, the amount of oil that leaks before reaching the set pressure is gentle. After that, even if the oil pressure value starts to decrease, the amount of oil leakage gradually decreases, and the flow rate and pressure characteristics do not appear as sharp as the initial relief valve.
Further, when the extrusion pressure is indicated by a solid line and the speed curve is indicated by a broken line in FIG. However, the rise is slow and it takes time to reach the set speed. The peaks of both the extrusion pressure and speed curve are delayed as shown by the arrows.

FIG. 4 shows the flow rate-pressure characteristics of the relief valve in the later stage of deterioration, and the general relationship between extrusion pressure and speed.
As the oil pressure increases, the starting pressure at which oil begins to leak begins to leak at a pressure lower than the relief valve in the early stage of deterioration. In addition, the amount of oil blown before reaching the set pressure reaches a peak.
Further, when the extrusion pressure is indicated by a solid line and the speed curve is indicated by a broken line in FIG. 4B, the relationship between the extrusion pressure and the speed of the main ram increases only gradually and cannot reach the set pressure. Also, the main ram speed, like the extrusion pressure, increases only gradually and cannot reach the set speed.

FIG. 5 shows a method for measuring the characteristics of the relief valve.
The horizontal axis represents time, the vertical axis represents oil pressure, main ram 9 speed, and hydraulic pump discharge, and the respective characteristics at the start of extrusion are shown in a graph.
In the figure, the set speed A is the moving speed of the main ram 9 according to the product. The pump discharge command B is a discharge amount of the hydraulic pump required when the main ram 9 moves at the set speed A.
Point C is the amount of excess oil at each measurement position. Point D is a necessary discharge amount (%) calculated from the actual speed of the main ram 9 at each measurement position.
The maximum pressure point 1 during extrusion is detected, and measurement is started from this point. The pressure, the discharge amount (%) of the pump discharge command C, and the actual speed are read at each point (1 to n) every −1 MPa from 1 which is the maximum pressure point. (Each discharge amount is displayed in% relative to the maximum discharge amount.)

Calculate the pump discharge amount B calculated in the calculation for the set speed A.
When main ram speed ≦ set speed A Y-axis = (discharge amount of pressure and pump discharge command C−pump discharge amount D corresponding to main ram speed) / (100−pump discharge amount D corresponding to main ram speed) × 100 %
X axis = pressure at the time of plotting The pump discharge amount is measured up to a pump discharge command value (target value of discharge amount) B (%).
When the above is plotted on a graph, the characteristics shown in FIG. 6 are obtained.
This graph is equivalent to the flow rate-pressure characteristic graph of FIG.

FIG. 7 shows an image of characteristic threshold values obtained by the above-described relief valve characteristic measurement method.
The area (1) is the initial relief valve characteristic, the area (2) is the initial relief valve characteristic, and the area (3) is the late relief valve characteristic.
As can be seen from this figure, the relief valve that has been deteriorated starts to leak at a low pressure, and at the same time, the peak of the relief amount also decreases.

FIG. 8 is based on the characteristics obtained in FIG. It is the figure which increased the set value (discharge amount) of pressure oil linearly with time.
An increase amount per time of the voltage signal which is a discharge amount command is set.
This increase amount coefficient supplements the leakage amount, prevents a delay at start-up, and allows the initial operation of the extrusion press to be performed.
For example, this coefficient is as follows.
In the case of (1), it takes 40 seconds to reach 0-10V. In the case of (2), it takes 30 seconds to reach 0-10V. In the case of (3), it takes 0-10V. The time will be 20 seconds.
During the production operation, the region in FIG. 7 is obtained by the above-mentioned calculation with a sampling time of 50 ms, for example, and if the deterioration progresses, for example, from region (1) to region (2) in FIG. Is automatically set so that the time taken to reach 0-10V is 30 seconds, while the time taken to reach 0-10V is 40 seconds.

  According to claim 2 of the present invention, when the deterioration of the relief valve progresses and the region shifts from the region (1) in FIG. 7 to the region (2) or from the region (2) to the region (3), An alarm is issued to perform maintenance.

Since this invention is the above structure, the following effects are acquired.
The characteristic of the pressure-leakage oil amount of the relief valve is automatically measured during normal production operation from the pump discharge command, pressure and actual speed at the start-up control at the initial stage of extrusion. In general, a pressure mold is set, and pressure is manually applied, and the characteristics are measured by the relationship between the discharge amount and pressure, the pressure rise time measurement, and the like.
By displaying the measured characteristics in a graph on a touch panel or the like, it is possible to visually convey the deterioration of the relief valve to the operator or the like.
By changing the control parameters at the start-up according to the degree of deterioration of the measured characteristics divided in advance, the pump discharge rate is increased to compensate for the amount of leaked oil, and even if deterioration progresses Production can be continued without significantly reducing productivity.
For this reason, an expensive relief valve can be used to the limit, it is not necessary to replace frequently, and cost reduction can be realized.
Also, frequent maintenance can be omitted.

1 End platen 2 Main cylinder 3 Tie rod 4 Die 5 Container 6 Billet 7 Extrusion stem 8 Main cross head 9 Main ram 10 Side cylinder 11 Side cylinder rod 12 Container holder

Claims (2)

In an extrusion press comprising a container moving means, and a billet loaded in the container by a main cylinder device is extruded from a die by an extrusion stem to form a profile,
Changes in characteristics due to aging of the relief valve are measured in normal production operation, the measured characteristics are graphed, and the control parameters at the start of extrusion are automatically changed according to the level of characteristic change Extrusion control method for an extrusion press.   The extrusion control method for an extrusion press according to claim 1, wherein a change from the initial state is visualized to alert the maintenance time.

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