JPH1099914A - Method and device for controlling ram speed of extrusion press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stabilize the fluctuation in the ram speed in the initial extrusion in an early stage by performing the ram speed control when the peak pressure in a main cylinder is detected during the pressure control of the main cylinder. SOLUTION: In the main cylinder pressure control PCA, a switching means 10e of a CPU 10 is operated to be connected to a second operating means 10c when the detected value of a pressure detector 8 becomes the peak, the command value to boost the moving speed of a ram 2 at the prescribed pattern is outputted by a ram speed setting device 12, and switching is performed to the ram speed control SCA. The command value from the ram speed setting device 12 is compared with a second comparator 10d to obtain the deviation. The deviation is converted into the valve opening adjust amount by the second operator 10c, and outputted to a comparator 7e of a valve means 7. The opening amount of a valve disk 7b is adjusted according to the deviation between the detected value of a valve opening detector 7d and the valve opening regulation quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a ram speed of an extrusion press for hot-extruding a metal such as aluminum or copper, or an iron-based alloy represented by carbon steel or stainless steel, and a method of controlling the method. The invention relates to a ram speed control device for implementing.

[0002]

2. Description of the Related Art In an extrusion press, a constant extrusion speed is controlled to ensure the quality of an extruded product. This is because when the extrusion speed fluctuates, the dimensions of the extruded product, especially when the extruded product is a tube, the thickness of the tube is not constant, and when the extrusion speed is too large than the set speed, flaws are generated on the product surface. That's why. The extrusion speed is controlled with the ram speed as an object to be controlled.

The ram speed of the extrusion press is shown in FIG.
As shown in (1), the speed peak P is inevitably generated until the billet of the material completely fills the container and starts to be extruded from the hole of the die. For this reason, if the ram speed (extrusion speed) is controlled constant from the start of extrusion, the valve opening of the valve means for controlling the supply of the high-pressure fluid that operates the ram of the extrusion press at the beginning of extrusion will cause the speed peak P to occur. As a result, the ram speed suddenly changes from open to closed and from closed to open. As a result, not only does the ram speed overshoot OS, but hunting (not shown) causes the ram speed at the initial stage of extrusion to become unstable.

As shown in FIG. 4, the overshoot OS and hunting of the ram speed in the initial stage of the extrusion are performed by adjusting the valve opening of a valve means for controlling the supply amount of the high-pressure fluid to the main cylinder for operating the ram of the extrusion press. In the case of adopting a method of switching to a ram speed control SCA for adjusting a valve opening of a valve means based on a detected value of a ram speed after a valve opening constant control VCA for setting and holding a constant value for a predetermined time at the start of extrusion. (For example, Japanese Patent Publication No. 59-7523 and Japanese Patent Publication No. 1-47)
246).

However, this method of switching from the valve opening constant control VCA to the ram speed control SCA is effective when the speed peak P inevitably generated at the beginning of extrusion is substantially constant, but the speed peak P greatly varies. If you do
The ram speed overshoot OS and hunting that occur at the beginning of extrusion cannot be sufficiently eliminated, and it takes too much time for the ram speed to stabilize, and the quality of the product extruded during this time deteriorates. doing.

That is, the above-mentioned speed peak P depends on the temperature of the material billet, the size of the gap between the container and the material billet, the magnitude of the valve opening of the valve means set at the start of extrusion, and the like. The time width is different. Therefore, in this case, if the switching timing from the valve opening constant control VCA to the ram speed control SCA is not appropriate, the difference between the actual ram speed immediately after the switching and the set ram speed becomes large, causing the ram speed to overshoot OS. It takes time to hunt and stabilize the ram speed.

That is, as shown in FIG. 5, when the switching timing from the valve opening constant control VCA to the ram speed control SCA is advanced and the ram speed is switched at the highest point of the speed peak P, at this time, the valve means The valve is closed,
Thereafter, the valve opening of the valve means is excessively opened, an overshoot OS occurs, and it takes time for the ram speed to stabilize.

As shown in FIG. 6, when the switching timing from the constant valve opening control VCA to the ram speed control SCA is delayed and the ram speed is switched to the lowest point of the speed peak P, as shown in FIG. At this point, the valve opening of the valve means is too open, an overshoot OS occurs, and it takes time for the ram speed to stabilize.

However, when the valve opening of the valve means and the set time are changed in the valve opening constant control VCA every time according to the magnitude of the speed peak P, the above-mentioned disadvantage is eliminated. However, it is practically impossible to know in advance the magnitude of the speed peak P, and even if it can be obtained, the setting operation is extremely troublesome, which leads to a reduction in work efficiency and an increase in product manufacturing cost. become.

As another means for avoiding the fluctuation of the ram speed in the initial stage of the extrusion, a valve opening constant control V
It is conceivable to increase the CA setting time. But,
In this case, the temperature of the material billet decreases and the deformation resistance of the material increases, so that the ram speed fluctuates, and the product quality of the product part extruded during that time cannot be adopted.

Therefore, it is desired to develop a method of controlling a ram speed of an extrusion press capable of stabilizing the fluctuation of the ram speed in the early stage of the extrusion at an early stage, and to develop a ram speed control device of the extrusion press for implementing the method. Was.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a method of controlling a ram speed of an extrusion press capable of stabilizing a fluctuation of a ram speed at an early stage of an extrusion at an early stage. An object of the present invention is to provide an extrusion press ram speed control device for performing the method.

[0013]

The gist of the present invention resides in the following ram speed control method and ram speed control device for an extrusion press (1) and (2).

(1) The supply of the high-pressure fluid for operating the ram of the extrusion press is followed by a constant valve opening control for setting and maintaining the valve opening of the valve means at a constant value for a predetermined time.
A ram speed control method in a metal extrusion press, which is controlled by a ram speed control that adjusts a valve opening of a valve means based on a detected value of a ram speed, wherein the valve opening constant control and the ram speed control are performed. Introduce main cylinder pressure control that adjusts the valve opening of the valve means based on the detected pressure value in the main cylinder, and switch to ram speed control at the time of peak pressure detection in the main cylinder during this main cylinder pressure control. Characteristic method of controlling ram speed of extrusion press.

(2) Valve means for controlling the supply of high-pressure fluid for operating the ram of the extrusion press; valve opening setting means for setting the valve opening of the valve means to a predetermined value at the start of extrusion; Cylinder pressure setting means for setting the initial pressure in the main cylinder to a predetermined value, cylinder pressure detecting means for detecting the pressure in the main cylinder, and ram speed for continuing the extrusion to a predetermined value Ram speed setting means, ram speed detecting means for detecting a ram speed, and calculating a valve opening adjustment amount of the valve means based on an input value from the cylinder internal pressure setting means and a detection value by the cylinder pressure detecting means. And a valve opening of the valve means based on an input value from the ram speed setting means and a value detected by the ram speed detecting means. A second calculating means for calculating the adjustment amount; and an input switching means for switching an input from the valve opening setting means to an input from the first calculating means or the second calculating means. Extrusion press ram speed control device.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, at the start of extrusion, the valve opening of the valve means is made smaller and the set time is shortened to perform a constant valve opening control. Main cylinder pressure control for increasing the internal pressure of the main cylinder according to a predetermined pressure increase pattern. Then, when the pressure in the main cylinder at the time of the main cylinder pressure control reaches a peak, the initial speed is set smoothly and sequentially higher, and thereafter, the speed is switched to the ram speed control of the speed pattern set to be constant.

When the control is performed in the order of "valve opening constant control → main cylinder pressure control → ram speed control", the ram speed generated at the time when the pressure in the main cylinder reaches a peak, ie, the initial stage of the extrusion. When the speed peak P is completed and the ram speed once decreases, the ram speed can be stably switched to the ram speed control, so that the ram speed does not overshoot or hunt at the initial stage of extrusion, and The ram speed stabilizes.
The result is an extruded product having uniform product quality over substantially the entire length.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A ram speed control method according to the present invention and a ram speed control device for implementing the method will be described below in detail with reference to FIGS.

FIG. 1 is a view showing an example of the configuration of a ram speed control device according to the present invention. In the figure, reference numeral 1 denotes a main cylinder of an extrusion press, 2 denotes a ram, 3 denotes a mandrel, 4 denotes a container, and 5 denotes a die. , 6 are die holders. In addition,
The mandrel 3 is omitted if the extruded product is not a tube.

The main cylinder 1 is supplied with a high-pressure fluid (indicated by an open arrow), which has been pressurized by an accumulator (not shown), through a valve means 7 and a ram 2 is provided.
Is moved to the left in the figure.

The valve means 7 comprises a valve body 7a and an operating cylinder 7 for driving a valve body 7b in the valve body 7a.
and a valve opening detector 7d for detecting the opening of the valve body 7b.
And a comparator 7e and an amplifier 7f. The valve means 7 compares a predetermined command value (electric signal) output from the CPU 10 to be described later with a value (electric signal) detected by the valve opening detector 7d by a comparator 7e to obtain a deviation. A value is obtained, and this deviation value is amplified by an amplifier 7f and given to an operating cylinder 7c to thereby provide a valve body 7b.
The flow rate of the high-pressure fluid supplied to the main cylinder 1 is adjusted by adjusting the opening degree.

The valve opening detector 7d includes a rack fixed to the valve body support shaft 7g, a pinion that meshes with the rack, and a rotary encoder (not shown) mounted on the pinion shaft. Consists of

The main cylinder 1 is provided with a pressure detector 8 as a cylinder pressure detecting means, which detects the pressure in the main cylinder and outputs the detected value (electric signal) by means of the cylinder internal pressure setting means. First comparator 10a in CPU 10 connected to a certain pressure setting device 9
Is entered.

Further, the ram 2 is provided with a speed detector 11 as ram speed detecting means, which detects the moving speed of the ram, and outputs the detected value (electric signal) as ram speed setting means. CPU 10 connected to speed setting device 12
To the second comparator 10d.

The speed detector 11 includes a rack fixed to the ram 2, a pinion that meshes with the rack, and a rotary encoder mounted on the pinion shaft, as in the case of the valve opening detector 7d. (Omitted), the first comparator 1 is provided in the CPU 10.
0a and the second comparator 10d, in addition to being connected to a valve opening degree setting device 13 which is a valve opening degree setting means, and via the first calculating means 10b.
0a and an input switching means 10e connected to the second comparator 10d via the second arithmetic means 10c.

The first calculating means 10b calculates the difference between the value (electric signal) detected by the pressure detector 8 obtained by the first comparator 10a and the command value (electric signal) from the pressure setting device 9. The deviation value is converted into a valve opening adjustment amount (electric signal), and the value is output to the switching means 10e.

The second calculating means 10c is provided with a second
The difference between the value detected by the speed detector 11 (electrical signal) obtained by the comparator 10d and the command value (electrical signal) from the ram speed setting device 12 is used as the valve opening adjustment amount (electrical signal). And outputs the value to the switching means 10e.

When extrusion is performed using the control device configured as described above, in the present invention, extrusion is performed as follows.

First, the switching means 10e in the CPU 10
Is connected to a valve opening setting device 13, and the valve opening and time of the valve means 7 at the start of extrusion are smaller and shorter than the conventional one as shown in FIG. In this state, the valve opening constant control VCA is performed.

Here, the valve means 7 at the start of extrusion is
The reason for setting the valve opening and time smaller and shorter than before is to reduce the impact force acting on the equipment and the workpiece at the start of extrusion, and switch to ram speed control as quickly as possible. This is because the length of the part where the quality of the extruded product inevitably occurs in the early stage of the extrusion is reduced as much as possible.

Next, after the valve opening constant control VCA is completed, the switching means 10e in the CPU 10 is operated to connect to the first calculating means 10b, and the main cylinder is operated by the pressure setting device 9 as shown in FIG. A command value (electric signal) for increasing the pressure in 1 in a predetermined pattern is output and switched to the main cylinder pressure control PCA.

In the main cylinder pressure control PCA, a command value (electric signal) from the pressure setting device 9 and a detection value (electric signal) by the pressure detector 8 are compared by a first comparator 10a. A deviation value is determined. The obtained deviation value is converted into a valve opening adjustment amount (electric signal) by the first computing unit 10b and output to the comparator 7e of the valve means 7. The valve opening adjustment amount is calculated by the comparator 7e.
Is input to the valve means 7, the valve opening detector 7d
A deviation value is obtained by comparing the detected value with the input valve opening adjustment amount, and an electric signal corresponding to the deviation value is amplified by an amplifier 7f and output to a valve actuating cylinder 7c to be output to a valve body 7a. The opening degree of the valve body 7b is adjusted to increase the pressure in the main cylinder 1 in a predetermined pattern given by the pressure setting device 9. As a result, as shown in FIG. 2, even if the speed peak P of the ram speed occurs at the initial stage of the extrusion, the valve opening of the valve means 7 does not fluctuate greatly during that period. Does not cause overshoot or hunting, and enables stable extrusion.

Subsequently, in the above-mentioned main cylinder pressure control PCA, when the value detected by the pressure detector 8 reaches a peak (determined by a differential value), in other words, the material bite charged in the container 4 Is completely filled and starts to be extruded from the hole of the die 5, the switching means 10e in the CPU 10 is operated to activate the second arithmetic means 10
2, a command value (electric signal) for increasing the moving speed of the ram 2 in a predetermined pattern is output by the ram speed setting device 12 as shown in FIG.
A.

In the ram speed control SCA, the command value (electric signal) from the ram speed setting device 12 and the detection value (electric signal) detected by the speed detector 11 are used in the second comparator 1.
A comparison is made with 0d to obtain a deviation value. The obtained deviation value is converted into a valve opening adjustment amount (electric signal) by the second calculator 10c and output to the comparator 7e of the valve means 7. Then, in the valve means 7 in which the valve opening adjustment amount is input to the comparator 7e, a deviation value is obtained by comparing the detection value of the valve opening detector 7d with the input valve opening adjustment amount, An electric signal corresponding to the deviation value is supplied to an amplifier 7f.
The output is amplified to the operation cylinder 7c and the opening degree of the valve body 7b in the valve body 7a is adjusted, and the moving speed of the ram 2 is moved in a predetermined pattern given by the ram speed setting device 12. As a result, as shown in FIG. 2, the ram speed at the initial stage of extrusion smoothly rises and reaches a predetermined speed without causing overshoot or hunting, and is stabilized early.

[0035]

According to the present invention, the ram speed fluctuating at the beginning of extrusion can be stabilized at an early stage. As a result,
An extruded product of uniform product quality over substantially the entire length is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a control device of the present invention.

FIG. 2 is a diagram showing a relationship among a ram speed, a valve opening, and a pressure in a main cylinder according to the present invention.

FIG. 3 is a diagram showing a relationship between a set speed and an actual speed in a conventional example in which ram speed control is performed from the beginning of extrusion.

FIG. 4 is a diagram showing valve opening set values and actual values in a conventional example in which only valve opening constant control and ram speed control are combined.

FIG. 5 is a diagram showing a relationship between a ram speed and a valve opening when switching timing to ram speed control is fast in a conventional example in which only the valve opening constant control and the ram speed control are combined.

FIG. 6 is a diagram showing a relationship between a ram speed and a valve opening when a switching timing to a ram speed control is late in a conventional example in which only the valve opening constant control and the ram speed control are combined.

[Explanation of symbols]

 1: Main cylinder, 2: Ram, 3: Mandrel, 4: Container, 5: Dice, 6: Die holder, 7: Valve means, 7a: Valve body, 7b: Valve body, 7c: Cylinder for valve operation, 7d: 7e: Comparator, 7f: Amplifier, 7g: Valve support shaft, 8: Pressure detector, 9: Pressure setter, 10: CPU, 10a: First comparator, 10b: First 10c: second computing device, 10d: second comparator, 10e: switching means, 11: speed detector, 12: ram speed setting device, 13: valve opening degree setting device.

Claims (2)

[Claims] The supply of high-pressure fluid for operating a ram of an extrusion press is based on a detected value of a ram speed, following a valve opening constant control for setting and maintaining a valve opening of a valve means at a constant value for a predetermined time. A ram speed control method in a metal extrusion press, wherein the ram speed control is controlled by adjusting a valve opening of a valve means. A ram of an extrusion press characterized by introducing a main cylinder pressure control for adjusting a valve opening degree of a valve means based on the ram speed control at the time of detecting a peak pressure in the main cylinder during the main cylinder pressure control. Speed control method. 2. A valve means for controlling the supply of a high-pressure fluid for operating a ram of an extrusion press; a valve opening setting means for setting a valve opening of said valve means to a predetermined value at the start of extrusion; Cylinder pressure setting means for setting the pressure in the main cylinder to a predetermined value, cylinder pressure detecting means for detecting the pressure in the main cylinder, and a ram for setting the ram speed for continuing the extrusion to a predetermined value. Speed setting means, ram speed detection means for detecting a ram speed, and a valve opening adjustment amount of the valve means is calculated based on an input value from the cylinder internal pressure setting means and a detection value by the cylinder pressure detection means. First for
Calculating means, and second calculating means for calculating a valve opening adjustment amount of the valve means based on an input value from the ram speed setting means and a value detected by the ram speed detecting means,
A ram speed control device for an extrusion press, comprising: input switching means for switching an input from a valve opening setting means to an input from a first calculation means or a second calculation means.