JPH05269750A - Clamping device and control method therefor - Google Patents

Abstract

PURPOSE:To move a movable mold in parallel to a fixed mold even with a variation in clamping reaction force of a molded piece by a method wherein when the molded piece is obtained while clamping the fixed mold and the movable mold with each other by a plurality of clamping cylinders, the clamping cylinders are individually controlled. CONSTITUTION:Hydraulic cylinder chambers 62 formed in the vicinity of a peripheral part of a fixed die plate 12. Solenoid servo valves 66a, 66b,...(66) are connected to, e.g. four clamping cylinders 65a, 65b...(65) each formed by inserting a piston in the hydraulic cylinder chamber 62a. A movable die plate 22 is moved forward to a predetermined position by a boost cylinder to be fastened to tie bars 61. By actuating the clamping cylinders 65 in place of the boost cylinder, the movable die plate 22 is moved in parallel to the fixed die plate 12 to start clamping and, at the same time, a melt resin is injected. For each of the clamping cylinders 65, a difference of an actual position or speed from an object value is found. If the found value exceeds a predetermined threshold, the solenoid servo valve 66 is so controlled by raising or lowering a specified speed as to move the movable die plate 22 in parallel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device and a control method therefor, and more particularly, to rolling / spreading of a molded product while clamping a mold such as a compression molding machine, an injection compression molding machine, or a press. And a control method thereof.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Application Laid-Open No. 63-157799 and Japanese Patent Application Laid-Open No. 63-157799 have been disclosed in a mold clamping device such as a compression molding machine, an injection compression molding machine, or a press for rolling and spreading a molded product while clamping the mold. As suggested in 1-264815,
There is one that maintains the parallelism of the movable platen by controlling a leveling cylinder provided on the fixed platen separately from the pressure cylinder. Alternatively, as proposed in Japanese Utility Model Laid-Open No. 62-185017, instead of the leveling cylinder, a plurality of pressure control cylinders controlled in parallel are arranged above the platen, and one pressure control cylinder is used as a master and the rest are There is one that maintains the parallelism of the movable plate by performing pressure molding by a master slave system which is the slave.

[0003]

However, the above-mentioned conventional Japanese Patent Laid-Open Nos. 63-157799 and 1-264 have been disclosed.
In 815, since the parallelism of the movable plate is to be maintained by the balance between the pressurizing force generated by the pressure cylinder and the counter force by the leveling cylinder, the force of the leveling cylinder and the force from the object to be molded with respect to the force of the pressure cylinder. Since the acceleration of the movable platen, that is, the speed of the movable platen is determined by the resultant force of the reaction forces, there are many causes of variations in the resultant force, and it is difficult to accurately control the speed of the movable platen. In particular, when it is desired to move the movable plate at a low speed, in order to balance the force of the leveling cylinder with respect to the pressurizing cylinder, from the viewpoint of the control of the leveling cylinder, the greater the force is, the closer to the stop the force is required. .. In other words, the greater the force, the greater the variation, which makes the balance condition unstable, and the control becomes more difficult at a speed closer to the stop required during mold clamping. Energy is wasted because the leveling cylinder opposes the pressurizing cylinder to counterbalance the force and stop the balance.

In Japanese Utility Model Laid-Open No. 62-185017, 1
With the book as the master and the rest as its slaves, the platen is balanced-controlled by multiple pressurizing cylinders, so even if there is a delay in the slave cylinder, the master cylinder proceeds as instructed and the platen cannot maintain the parallel inclination. ..
Further, recently, there has been a great demand for large-sized parts with high precision, but there is a problem that there is no good mold clamping device and method.

The present invention has been made in view of the above problems, and relates to a mold clamping device and a control method therefor, and in particular, a molding / rolling machine for a molded product while clamping a mold such as a compression molding machine, an injection compression molding machine, or a press. Regarding a mold clamping device for spreading and its control method, the purpose thereof is to control a plurality of mold clamping cylinders independently to control a parallel movement and a moving speed. For example, one of the mold clamping cylinders is delayed. In this case, the objective is to focus on parallel movement control rather than movement speed control, and to perform parallel movement.

[0006]

In the invention according to the present invention, in the first invention, a molding material is housed between a fixed mold and a movable mold, and molded by clamping a plurality of mold clamping cylinders. In a mold clamping device for molding an article, at least when the movable mold moves in parallel to the fixed mold and moves toward the fixed mold at a predetermined variable speed, the mold clamping cylinder lags behind the command, When the difference between the delay amounts of the mold clamping cylinders exceeds a predetermined value, the movement of the mold clamping cylinders is accelerated / decelerated so as to be within the predetermined value, and the mold clamping cylinders are moved in parallel.

In the second aspect of the invention, which is mainly based on the first aspect, when the movable die moves in parallel to the fixed die, the actual movement of the movable die rather than the command value of the target position or the target speed is performed. When the difference in either position or speed exceeds a predetermined threshold value, the command speed is increased or decreased.

Further, according to a third aspect of the invention, which is mainly based on the first or second aspect, the parallel movement of the movable die with respect to the fixed die is corrected, and the actual value is larger than the command value of the target position or the target speed. When the difference between the moving position and the speed becomes smaller than a predetermined threshold value, the deceleration of the command speed is stopped or the command speed is accelerated.

According to the fourth aspect of the invention, a fixed die plate for holding the fixed die, a movable die plate for holding the movable die, and a plurality of movable die plates for moving the fixed die plate to perform die clamping. A mold clamping device comprising a mold clamping cylinder, an accumulator for supplying pressure oil to the mold clamping cylinder, and a pressure reducing valve for reducing the pressure oil of the accumulator. A measuring device that measures the length and a command value for the target length of each mold clamping cylinder are output, and the difference between the actual length of each mold clamping cylinder obtained by the measuring device and the target length is compared with a predetermined value. It consists of a control device that issues an acceleration / deceleration command when the magnitude is small, and an electromagnetic servo valve connected to each mold clamping cylinder that opens and closes according to a command from the control device.

In the fifth aspect of the invention, the pressure supplied to the mold clamping cylinder is set by the pressure reducing valve, and meter-in / meter-out is controlled by the electromagnetic servo valve.

[0011]

According to the above construction, when the speed control and the parallel control are simultaneously performed by the plurality of actuators of the mold clamping means, for example, the resin injected into the cavity is not uniform as shown in FIG. Even if the movable mold is tilted, stop the speed command to the advancing mold clamping cylinder and issue a command value to advance the delayed mold clamping cylinder, that is, with respect to the target moving position. A delay occurs in the actual position, and when the value of this delay exceeds a predetermined threshold value, an acceleration / deceleration command is issued, so that parallel movement control is reliably performed.
In addition, the electromagnetic servo valve controls meter-in / meter-out and the pressure is controlled by the pressure reducing valve, so high pressure is applied quickly to the delayed mold clamping cylinder, so the pressing force increases and It is easy to move.

Further, since the movements of the mold clamping cylinders arranged on the tie bars are independently controlled, the movable mold can be moved in parallel with the fixed mold even if the mold clamping reaction force varies, and the mold can be uniformly moved. Large-sized molded products with good wall thickness accuracy, uniform density and good surface quality can be obtained. In addition, because the plastic material is compressed and spread in the wide cavity and flows, it is possible to compensate for the fluidity and perform molding without impairing the physical properties of the material. Since the pressure applied to the object becomes uniform and the density becomes uniform, it is possible to perform molding with less distortion and warpage. Furthermore, since the movement of the movable die plate is changed from the advancing / retreating means to the mold clamping means, and the equilibrium control is performed, the share edge clearance of the movable die and the fixed die can be reduced, and the rubbing travel can be lengthened. The quality can be improved. In addition, damage and wear of the guide pin can be reduced.

[0013]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic view of a mold clamping device and an electromagnetic servo valve portion for explaining the present invention. FIG. 2 is a schematic view of a mold clamping portion for explaining the present invention, and this embodiment is a horizontal type, but may be a vertical type. FIG. 3 is a block diagram of a control device as an example of the present invention. FIG. 4 is a block diagram of the overall control principle of the present invention, in which a blank frame is a transfer function including an electromagnetic servo valve, a cylinder, a linear scale and an integrator. FIG. 5 is a block diagram of control of each cylinder. 6 is a schematic side view of an injection compression molding apparatus using the mold clamping apparatus of the present invention, FIGS. 7 and 8 are hydraulic circuits of the injection compression molding apparatus, and FIG. 9 is a time chart diagram of the injection compression molding apparatus during mold clamping. is there.

In FIG. 6, an injection compression molding apparatus 1 includes a compression molding apparatus 2, an injection apparatus 3, and a control apparatus 4 (shown in FIG. 3).
Consists of. The compression molding device 2 includes a fixed die plate portion 10 for holding a fixed die, a movable die plate portion 20 for holding a movable die, and a die advancing / retreating device 30 for rapidly advancing / retreating the movable die plate with respect to the fixed die plate.
And a mold clamping device 60 for performing mold clamping while moving and moving the movable die plate relative to the fixed die plate to compress and spread the plastic material after the movable die plate approaches the fixed die plate and reaches a predetermined position. Become. Further, the injection device 3 is provided with an injection cylinder part 90 for injecting a plastic material into the compression molding device 2, and the injection cylinder part 90 is provided in the heating cylinder 9.
A slide cylinder (not shown) fixed to the compression molding device 2 is slidably mounted in the fixed mold 11 of the compression molding device 2. A screw 92 is closely inserted into the heating cylinder 91 of the injection cylinder portion 90, and the screw slides in the direction of the mold by driving a hydraulic cylinder (not shown) to inject the plastic material.

In the compression molding apparatus 2, a fixed die plate portion 10 is fixedly installed on one end of the bed 7, and the fixed die plate portion 10 includes a fixed die 11 and a fixed die plate 12 holding the fixed die 11. Consists of. Further, the fixed die plate portion 10 is provided with a mounting portion 30a of the mold advancing / retracting device 30 and a mold clamping device 60. Further, a guide rail 8 is fixedly installed on the bed 7, and a movable die plate portion 20 standing upright on the ground is disposed on the guide rail 8. The movable die plate portion 20 is movable with a movable die 21. Movable die plate 22 holding die 21 and movable die plate 2
Consisting of a linear guide bearing 23 that holds 2
A linear guide bearing 23 is slidably and pivotally attached to the guide rail 8. Further, the movable die plate portion 20 is provided with a locking device 210, an ejector device 220, and a mounting portion 30b of the mold advancing / retracting device 30.
Further, at the other end of the bed 7, a support plate 9 that guides a tie bar 61, which will be described later, is slidably mounted. The movable die plate 22 is slidably guided to the fixed die plate 12, and the movable die plate 2 is moved during mold clamping.
A tie bar 61 of a mold clamping device 60 for pulling 2 is provided. Further, in a substantially central portion of the fixed die plate 12, a cylinder 91 (hereinafter referred to as a heating cylinder 91) that heats the plastic material of the injection device 3 that injects the plastic material such as resin into the cavity portion 14 is provided in the fixed mold 11. Abutting.

In FIG. 6, the mold clamping device 60 has a plurality of hydraulic cylinder chambers 62 formed in the fixed die plate 12,
A piston 63 with a rod-shaped hollow hole (hereinafter referred to as piston 63) is pivotally inserted into this, and a piston cover 64 is further inserted. The piston cover 64 is fixed to the fixed die plate 12, and the cylinder chamber 62
a and 62b are formed. In FIG. 7, four mold clamping cylinders 65 having the above-mentioned configuration are arranged near the outer peripheral portion of the fixed die plate 12 and 65a, 65b, 65c and 65d. An electro-hydraulic servo valve (hereinafter referred to as an electromagnetic servo valve 66) 66a, 66 is provided in each mold clamping cylinder 65.
b, 66c, 66d are connected in parallel to the pipe 67, and each electromagnetic servo valve 66 operates independently in response to a command from the control device 4 so that the movable mold 21 moves in parallel to the fixed mold 11. The electromagnetic servo valve 66 controls meter-in / meter-out. The variable capacity hydraulic pump 7 is connected to the pipe 67 via a variable flow rate adjusting valve 68 and a check valve 69.
It is connected to 0. Further, an electromagnetic pressure reducing valve 71 with a pilot (hereinafter referred to as pressure reducing valve 71) is provided in the pipe 67, and an accumulator 72 is provided between the variable flow rate adjusting valve 68 and the check valve 69.

The pressure of the accumulator 72 is limited by the pressure reducing valve 71 to a predetermined pressure according to the mold clamping force due to the size of the resin or the molded product. In addition, the cylinder chamber 62
A relief valve 73 is provided at b. Also, piping 67
A pipe 201 is branched from the pipe 201, and a cylinder 223 of the ejector device 220 is arranged in the pipe 201 via an electrohydraulic servo valve 202 for the ejector. further,
A pipe 211 is branched from a pipe 67, and a hydraulic fixing device 213 of a locking device 210 is arranged in the pipe 211 via a locking electromagnetic switching valve 212, and the movable fixing die plate 22 is fixed to the hydraulic fixing device 213. When a predetermined position is reached with respect to the die plate 12, the diver 61 and the movable die plate 22 are locked, and the mold opening / closing operation is performed by the mold clamping cylinder 65 when locked and boosted when not locked. It is used for switching performed by the cylinder 31.

As shown in FIG. 3, the control device 4 includes, for example, one main computer 5 and four microcomputers 6.
a, 6b, 6c, 6d (in the case of four mold clamping cylinders), each microcomputer 4 has a respective mold clamping cylinder 65a, 65a.
Position sensors 7a, 7 arranged for controlling b, 65c, 65d for measuring the length of each mold clamping cylinder.
b, 7c, 7d and the electromagnetic servo valve 6 for switching the pressure oil for driving the mold clamping device 60 in response to a command from the microcomputer.
6a, 66b, 66c, and 66d.
In addition, each microcomputer 4 is connected to the main computer 5, and a position sensor 100 that detects a distance between the movable die plate 22 and the fixed die plate 12 when the mold is separated from a predetermined position is provided. Pressure sensor 1 for determining whether the stop device is activated and locked
01 is connected. In addition, the main computer 5
The electromagnetic switching valve 30a for switching the pressure oil for driving the advancing / retreating device 30, the electromagnetic switching valve 40a for switching the pressure oil for driving the locking device 40, and the moving distance of the movable mold 21 depending on the moving distance. It is connected to the die stroke setting means 120 for inputting the operating position and speed of the advancing / retreating device 30, the mold clamping device 60, or the injection timing of the plastic material, and the injection amount setting means 130 for setting the injection amount of the plastic material. , And each is controlled by a predetermined command.

In the above embodiment, as a means for measuring the relative positions of the movable die plate and the fixed die plate, the main bodies of the four linear encoders are fixed to the fixed die plate,
Although the moving distances at the four corners of the movable die plate are measured, a sensor may be provided in each cylinder for the measurement. Although four mold clamping cylinders are used, three mold clamping cylinders or four or more mold clamping cylinders may be used. Further, although four microcomputers are arranged according to the number of cylinders, if the accuracy may be slightly degraded, one computer may be used for calculation, or two microcomputers and one main computer. May be used.

Next, the speed control and parallel control of the present invention will be described. FIG. 2 is a schematic view showing the configuration of the mold clamping of the present invention, where the W surface shows the mounting surface of the fixed die plate 12, and the V surface
The surface indicates the mounting surface of the movable die plate 22. Also, W
A point Wa on the surface indicates a position where the left end surface of the piston 63 of the mold clamping cylinder is in contact with the fixed die plate 12, and a point Va on the surface V indicates a position where the tie bar 61 is locked by the hydraulic fixing device 213. .. However, in the following description, in order to facilitate the description, the mold clamping cylinder 65 is replaced between the points Wa and Va, and the mold clamping cylinders 65a are set to length y1, 65b to y2, and 65c to y3. , 65d
Is replaced with y4, and the respective lengths are replaced.

In order to reach the target position without any deviation, it is necessary to feed back the integral of velocity.
That is, the position may be proportionally controlled as the integral of the velocity. For this reason, the mold clamping cylinder 65 moves the target speed dr /
If the target position (that is, the target length) when moving at dt is r, and the proportional feedback gain that brings the length of each mold clamping cylinder closer to the target length r is K1, the command value for y1 is -K1. The command value for (y1-r) y2 is -K1 (y2-r), the command value for y3 is -K1 (y3-r), and the command value for y4 is -K1 (y4-r).

In addition, in order to perform parallel mold control and mold clamping, the command value to each cylinder is corrected so as to correct the tilt and twist of the movable die plate 22 pulled by the four-axis actuator. There is a need to. At this time, the vertical inclination is y1 + y4- (y2 + y3) = y1-y2-y3 + y
4, given by. In consideration of the sign, the correction amount applied to each mold clamping cylinder is as follows: For y1, -k1 (y1-y2-y3 + y4) For y2, For k1 (y1-y2-y3 + y4) y3, For k1, k1 (y1- y2-y3 + y4) With respect to y4, -k1 (y1-y2-y3 + y4) is obtained.

The left and right inclinations are y1 + y2- (y3 + y4) = y1 + y2-y3-y
4, given by. In consideration of the sign, the correction amount applied to each mold clamping cylinder is: -k2 (y1 + y2-y3-y4) for y1 -k2 (y1 + y2-y3-y4) For y3, k2 (y1 + y2) -Y3-y4) For y4, k2 (y1 + y2-y3-y4) is obtained.

The twist of the diagonal line is (for example, the twist of Ya and Yd), y1 + y3- (y2 + y4) = y1-y2 + y3-y
4, given by. In consideration of the signs, the correction amount applied to each mold clamping cylinder is -k3 (y1-y2 + y3-y4) for y1, k3 (y1-y2 + y3-y4) for y3, -k3 (y1 -Y2 + y3-y4) For y4, k3 (y1-y2 + y3-y4) is obtained. If the above three correction amounts, and are added to the speed command value of each mold clamping cylinder, the feedback which corrects the tilt in the vertical and horizontal directions and the twist of the diagonal line is obtained.

In the above, feedback gains k1, k
Assuming that 2 and k3 have the same value k, three correction amounts,
, And the correction amount for correcting the tilt in the vertical and horizontal directions and the twist of the diagonal line is −k (3y1-y2-y3-y4) y2, −k (−y1 + 3y2-y3-y4) ) For y3, -k (-y1-y2 + 3y3-y4) For y4, -k (-y1-y2-y3 + 3y4).

In addition, the average value Y of the length of each mold clamping cylinder
When rearranging using, Y = (y1 + y2 + y3 + y4) / 4, and for y1, -K2 (y1-Y) y2, -K2 (y2-Y) For y3, -K2 (y3-Y) y4 On the other hand, -K2 (y4-Y) is obtained. However, K2 = 4k. That is, feeding back the inclinations of the vertical and horizontal directions and the twist of the diagonal line with the same weight is equivalent to feeding back the deviation from the average value of the mold clamping cylinder length to each mold clamping cylinder. In order to control the parallelism without deviation, it is necessary to feed back the integration of the deviation from the average value.
K2 becomes an integral feedback gain.

Summarizing the speed control and the parallel control as described above, the speed control and the parallel control are summarized as follows: The command value for y1 is -K1 (y1-r) -K2 (y1-Y) The command value for y2 is- The command value for K1 (y2-r) -K2 (y2-Y) y3 is -K1 (y3-r) -K2 (y3-Y) y4 is -K1 (y4-r) -K2 (y4 -Y).

A block diagram of the above control is shown in FIG.
As shown in. Here, yi: the length of each mold clamping cylinder, i = 1 to 4, r: the target length of the actuator when the movable die plate moves at the target speed dr / dt, K1: the target length of each cylinder Is a proportional feedback gain that brings the cylinders closer to, Y: an average value of the cylinder lengths, K2: an integral feedback gain that brings each cylinder closer to the average value Y. A block diagram for each mold clamping cylinder is as shown in FIG. 5, and an example of the mold clamping cylinder 65a and the electromagnetic servo valve 66a is shown in the figure.

Next, an example of the operation of the injection compression molding method for plastics will be described. In order to start stamping, the retractable movable die plate 22 is moved to the boost cylinder 3
By 1, the high speed mold is closed to bring it closer to the fixed die plate 12. At this time, an unillustrated logic valve or the like is opened and the discharge amount of the variable pump is set to the rod side 3 of the boost cylinder 31.
It is sent to 1b and moves to the fixed mold side at a rapid speed.

When the movable die plate 22 reaches a predetermined position with respect to the fixed die plate 12 (position f1 in FIG. 9), the tie rod 61 and the movable die plate 22 are fixed by the hydraulic fixing device 213 of the locking device 210. The movable die plate 22 is stopped or decelerated. When the movable plate 22 is stopped or decelerated, the locking device 210 is operated to lock and fix the tie rod 61 and the movable die plate 22. Whether or not the tie bar 61 is locked by the hydraulic fixing device 213 of the locking device 210 is determined by the pressure sensor 101.
The pressure may be detected.

When the locking by the locking device 210 is completed,
Switching the electromagnetic servo valve 66 of the mold clamping device 60, the cylinder chamber 6
The pressure oil from the accumulator 72 is sent to 2a to move the movable mold 21 to the fixed mold side to perform the mold closing step, but as shown in the figure, the movable mold 21 and the fixed mold 11 do not come into contact with each other. Yes, a predetermined amount (Z shown in FIG. 6: usually 2 mm to 3
The mold closing process is performed from the opened state and the molten resin is injected. At this time, the locking device 2
When it is confirmed that the locking by 10 is completed by the increase of the pressure from the pressure sensor 101, the same sampling signal generated by the main computer 5 triggers the microcomputers 6a, 6b, 6c, 6d of the respective cylinders to simultaneously control the length of each cylinder. (Y1, y2, y3, y4) is measured and transmitted to the main computer 5. In the main computer 5, the length of each sent cylinder (y1, y2, y3, y
The average value Y is calculated from 4), and the average value Y of the calculation result and the target cylinder length r are sent from the main computer 5 to the microcomputers 6a, 6b, 6c and 6d of the respective mold clamping cylinders.

The microcomputer 6 for each axis obtains the command value according to the information sent from the main computer 5 as shown in FIG. 5, and controls the electromagnetic servo valve 66 of the corresponding mold clamping cylinder 65. For example, in the i-th mold clamping cylinder 65i, the i-th microcomputer determines the command value for yi as -K1 (yi-r) -K2 (yi-Y) (1), The electromagnetic servo valve 66i is controlled.

By repeating this step in sequence, the (V) surface of the movable die plate 22 which was initially inclined moves to the fixed die plate 12 while it moves toward the fixed die plate 12 like the (P) surface. It will be parallel. Further, when the movable die plate 22 advances and the reaction force from the object to be compressed becomes larger than the force of the mold clamping cylinder, the movable die plate 22 cannot move at the set speed (dr / dt), and the above (1 ) Expression [(yi-r), where (i = 1
~ 4) The same applies to the following], and Q of FIG.
The point b is delayed, and the inclination starts to occur like the (Q) plane. As described above, in order to determine the magnitude of (yi-r), the magnitude may be compared with a preset threshold value.

For example, when (yi-r)> Ksup, the command value of the command speed (dr / dt) is reduced to decelerate. Further, the inclination is corrected by the command value, and the magnitude is compared with a preset threshold value. For example, when (yi-r) <Kinf, the command value of the command speed (dr / dt) is increased. To accelerate. At this time, Kinf <Ksup may be set so that the switching of acceleration / deceleration does not become unstable, but they may be equal. In the above, if Kinf ≦ (yi−r) ≦ Ksup, a method of maintaining the current speed without performing acceleration / deceleration, or continuing deceleration during deceleration and continuing acceleration during acceleration The acceleration and deceleration may have hysteresis.

In the above, the correction of the inclination in FIG. 1 will be described by way of an example. When the reaction force from the object to be compressed 15 becomes larger than the force of the mold clamping cylinders 65a, 65b, 65c, 65d, the mold clamping cylinders 65a, 65b, 65.
c, 65d actual position yi (where i = 1 to 4)]
Is later than the command value. At this time, the main computer 5 decelerates the command speed dr / dt to mitigate the increase of the absolute value of (yi-r), and K1 (y
The control of the moving speed by the item i-r) is stopped. At this time, for example, if the mold clamping cylinder 65b is delayed and the movable die plate 22 is tilted (X), the microcomputer 6b of the mold clamping cylinder 65b uses K2 (y2- for parallel control).
In response to the correction of the item Y), the electromagnetic servo valve 66b is instructed to increase the opening so as to eliminate the delay. This allows
The electromagnetic servo valve 66b has a meter-in opening 6 as shown in FIG.
6 bh and the meter-out opening 66 bs open greatly, and the pressure of the accumulator 72 does not receive resistance up to the set pressure of the pressure reducing valve 71 (less than the set pressure when the resin can be pushed) in the chamber of the mold clamping cylinder 65b. 6
Acts rapidly on 2a.

Further, at this time, the mold clamping cylinder 65a,
Similarly, the speed control [K1 (yi-
r), but i = 1, 3, 4] is corrected, but the command speed dr / dt is decelerated, so the influence of speed control is small, and [K2 (yi-Y) for parallel control is used. ),
However, the correction of the item of i = 1, 3, 4] works correctly and the control for maintaining the parallelism is performed. At that time, the electromagnetic servo valve 66a
The meter-in opening 66ah and the meter-out opening 66as are closed as shown in the drawing, or slightly open. At this time, even if the pressure is slightly open, the pressure of the accumulator 72 receives resistance due to meter-in / meter-out, so that the pressure is balanced at a low pressure that can push the resin without reaching the set pressure by the pressure reducing valve 71. As a result, a high pressure rapidly acts on the side of the mold clamping cylinder where the reaction force of the resin is larger, so that the force pushing the resin is increased and the movable mold 21 becomes parallel to the fixed mold 11 quickly. ..

Further, in the above embodiment, the example in which the delay of (y2-r) is detected is shown. However, normally, the electromagnetic servo valve is controlled by meter-in / meter-out, and the set pressure of the pressure reducing valve is quickly set. Since the force is applied, the output of the mold clamping cylinder quickly acts on the imbalance of the reaction force generated by the tie bar 61 such as the object to be compressed, so that the accuracy of the parallel movement is greatly improved. The parallel correction of the movable mold 21 is made by the signal from the position sensor 7b through the microcomputer 6b.
When it falls below a predetermined threshold, the main computer 5
As described above, the speed increasing command value is issued again, and the movable die plate 22 returns to the initial predetermined speed.

Although the above embodiment has been described as a mold clamping device for an injection compression molding machine, it goes without saying that it can be used for a mold clamping device such as a compression molding machine, an injection molding machine, or a press machine. Further, in the above-described embodiment, the example in which the mold clamping is performed using the tie bar has been described, but when the movable die plate is directly moved by using the mold clamping cylinder, the control is performed using the above invention. Is also good.

[0039]

As described above, according to the present invention,
When speed control and parallel control are performed simultaneously by multiple actuators of the mold clamping means, a delay occurs in the actual position with respect to the target movement position, and the value of this delay exceeds a predetermined threshold value. Occasionally, an acceleration / deceleration command is issued, so parallel movement control is reliably performed, and the electromagnetic servo valve controls meter-in / meter-out, and the pressure reducing valve controls pressure. In contrast, since the high pressure operates quickly, the pressing force increases and the parallel movement is surely performed. Furthermore, since the movements of the mold clamping cylinders arranged on the tie bars are individually controlled, the movable mold can be moved parallel to the fixed mold even if the mold clamping reaction force varies, and uniform wall thickness accuracy can be achieved. A large molded product with a uniform density and good surface quality can be obtained. For example, a molded product (length 1000 mm, width 150 mm, thickness 2.0 m
As a result of molding m), the variation in thickness is within 10 μm. Further, the parallelism during movement is within 50 μm during movement. Since the plastic material is compressed and spread in a wide cavity and flows, it is possible to supplement the fluidity and perform molding without deteriorating the physical properties of the material, and the movement of the movable mold can be adjusted variably. Since the pressure becomes uniform and the density becomes uniform, it is possible to perform molding with less distortion and warpage. Furthermore, since the accuracy of the parallel movement is improved, the shear edge clearance between the movable mold and the fixed mold can be reduced, and the excellent effect that the damage and wear of the guide pin can be reduced can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a mold clamping device and an electromagnetic servo valve portion for explaining the present invention.

FIG. 2 is a schematic view of a mold clamping portion of the present invention.

FIG. 3 is a block diagram of a control device according to an example of the present invention.

FIG. 4 is a block diagram of the overall control of the present invention.

FIG. 5 is a block diagram of control of each cylinder of the present invention.

FIG. 6 is a side view of an injection compression molding device.

FIG. 7 is a hydraulic circuit diagram of the injection compression molding device.

FIG. 8 is a hydraulic circuit diagram of the injection compression molding device.

FIG. 9 is a time chart of injection compression molding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection compression molding device 2 Compression molding device 3 Injection device 4 Control device 10 Fixed die plate part 11 Fixed mold 12 Fixed die plate 14 Cavity part 20 Movable die plate part 21 Movable mold 22 Movable die plate 30 Mold advancing / retracting device 31 Boost Cylinder 60 Mold Clamping Device 65 Mold Clamping Cylinder 66 Electro-hydraulic Servo Valve 68 Variable Type Flow Control Valve 71 Electromagnetic Bylot Pressure Reduction Valve 72 Accumulator 90 Injection Cylinder 100 Position Sensor 101 Pressure Sensor 210 Locking Device

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B29C 45/76 7365-4F B30B 15/24 C 7819-4E // B30B 15/22 C 7819-4E

Claims (5)

[Claims] 1. A mold clamping apparatus for accommodating a molding material between a fixed mold and a movable mold, and molding a molded product by clamping a plurality of mold clamping cylinders, wherein at least the movable mold is a fixed mold. When the mold clamping cylinder lags behind the command and the difference in the amount of delay between the mold clamping cylinders becomes larger than the specified value while moving in parallel and moving toward the fixed mold at a predetermined variable speed. Further, a method of controlling a mold clamping device, characterized in that the mold clamping cylinder is accelerated and decelerated so as to be within a predetermined value to perform parallel movement. 2. When the movable mold is moving in parallel to the fixed mold, either the difference between the target position and the actual position or the difference between the target speed and the actual speed has a predetermined threshold value. The method for controlling a mold clamping device according to claim 1, wherein the command speed is increased or decreased when the speed exceeds the limit. 3. The parallel movement of the movable mold with respect to the fixed mold is corrected, and either the difference between the target position and the actual position or the difference between the target speed and the actual speed becomes smaller than a predetermined threshold value. The method for controlling a mold clamping device according to claim 1 or 2, wherein deceleration of the command speed is stopped or command speed is accelerated. 4. A fixed die plate for holding a fixed die, a movable die plate for holding a movable die, and a plurality of die clamping cylinders for moving the movable die plate with respect to the fixed die plate to perform die clamping. In a mold clamping device consisting of an accumulator that supplies pressure oil to the mold clamping cylinders and a pressure reducing valve that reduces the pressure oil of the accumulator, measure the length of each mold clamping cylinder by installing it in the mold clamping means or by disposing it in the vicinity. When the difference between the actual length of each mold clamping cylinder and the target length obtained by the measuring device is larger than the predetermined value, A mold clamping device comprising a control device for issuing an acceleration / deceleration command and an electromagnetic servo valve connected to each mold clamping cylinder that opens and closes according to a command from the control device. 5. The pressure to be supplied to the mold clamping cylinder is set by a pressure reducing valve, and is metered in by an electromagnetic servo valve.
The mold clamping device according to claim 1, wherein the meter-out is controlled.