JPH07112474A - Control of movable member in molding machine - Google Patents

Abstract

PURPOSE:To avoid the collision of the movable member and fixed member in an injection molding machine or to relax the impact force at the time of collision. CONSTITUTION:The moving speed of a movable member 8 moved by the drive means 9 of an injection molding machine 1 is detected and, on the basis of this moving speed and a speed reducing time required to stop the movable member 8 during movement or to decelerate the movable member to speed rnear to stop, the overrun distance of the movable member 8 is calculated from a braking start position and the braking start position of the movable member is set on this side separated by the overrun distance from the moving limit position of the movable member 8 and, when the movable member 8 reaches the braking start position, the drive means 9 is changed over to braking control.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a movable member in a molding machine, and more particularly to a movement control of a movable member having a movement limit position set with respect to a fixed member provided in an injection molding machine. The present invention relates to a method of controlling a movable member that is suitable for use.

[0002]

2. Description of the Related Art Generally, a molding machine such as an injection molding machine is provided with an injection screw for injecting a molten material into a mold cavity and a movable member such as a movable plate on which a movable mold is mounted. These movable members are fixed members (for example, in the case of an injection screw, a heating cylinder into which this injection screw is inserted, by a fluid pressure actuator such as a hydraulic cylinder, or a mechanical driving means such as a ball screw mechanism. In addition, the movable mold attached to the movable plate is moved relative to the fixed mold attached to the fixed plate opposite to the movable plate).

By the way, in such an injection molding machine, in order to avoid damage due to collision between the movable member and the fixed member, the injection screw is stopped at a short distance from the inner surface of the heating cylinder. The forward stroke is set, and in the movable plate, the movable mold is decelerated so as to reach a predetermined speed at the time when the movable mold comes close to the fixed mold. It is regulated by the abutment of the mold.

More specifically, in the above-mentioned injection screw, first, by the speed control of advancing at a predetermined speed,
The molten resin is advanced to the vicinity of the foremost end of the forward stroke to inject the molten resin into the mold cavity, and the deceleration process is performed at the time of injecting the molten material in an amount that fills the mold cavity, and under a predetermined pressure. By shifting to the pressure control for advancing to the most advanced position, holding pressure is maintained for the material injected into the mold cavity through the material remaining between the tip of the injection screw and the inner surface of the tip of the heating cylinder. It is designed to give.

The injection screw is normally stopped by the balance between the set holding pressure and the pressure of the material injected into the mold cavity, and further exceeds the set forwardmost end. In such a case, the position is detected and the brake is stopped by forcible braking control.

In the former movable platen, the movable platen is moved forward with a predetermined speed toward a fixed mold attached to the fixed platen, and the interval between the movable platen and the fixed mold is predetermined. When the distance reaches the distance, that is, when the front end of the forward stroke is reached, deceleration processing is performed.Then, by further advancing in the low speed state after deceleration, the movable die gently contacts the fixed die. Contacted,
After that, both molds are clamped with a predetermined pressure.

[0007]

However, in such a conventional injection molding machine, the following problems to be solved remain. Hereinafter, this problem will be described in detail.

When the above-mentioned movable member is an injection screw, the deceleration processing and the stopping processing at the most advanced position are
This is performed based on the position information of the injection screw set when the drive conditions of the injection molding machine are set.

However, for example, if the material is weighed less than the set value, the injection screw is advanced under speed control for injection, and then decelerated at the set position. However, since the amount of measurement is small and the injection amount into the mold cavity is less than the set value, the pressure in the mold cavity where the molten material is injected is also low, and the pressure control is performed. The balance between the pressure acting on the injection screw and the pressure given by the material is upset, and the injection screw is advanced to the most advanced position while the deceleration process is incomplete.

Then, the injection screw is advanced to the most advanced position in the state where the deceleration processing is thus incomplete, the information is detected based on the position detection of the injection screw, and the compulsory braking control is performed. However, as described above, the deceleration process of the injection screw is incomplete, the deceleration is not sufficiently performed, and the deceleration rate during braking control is a fixed value. Depending on the initial speed of the injection screw, the inertial force delays the stop of the injection screw,
The tip of the injection screw collides with the tip inside the heating cylinder, the tip surface of the injection ram advancing the injection screw collides with the rear end surface of the heating cylinder, or the front end surface of the piston portion of the injection ram and the tip inside the injection cylinder. The injection screw is stopped by the collision with.

On the other hand, such a problem as the collision of the respective parts occurs due to the setting error of the stop position by the operator in addition to the above-mentioned causes. In recent years, the injection speed has been significantly increased to 800 to 1000 mm / sec, as compared to the conventional 100 to 300 mm / sec. Therefore, the above-mentioned problems occur due to an increase in the initial speed at the start of braking control. Not only is the degree increased, but the scale of damage to the equipment in the event of a failure also increases.

Further, when the movable member is a movable plate,
The cause of the problem of collision is that the start position of the deceleration process is set incorrectly and the deceleration rate is fixed, and it is almost impossible to deal with the change in the initial speed of the movable member at the start of the deceleration process. If such a problem occurs, the expensive mold will be damaged.

The present invention has been made in view of the above-mentioned conventional problems, and an object thereof is an injection molding machine capable of surely preventing a collision with a fixed member when the movable member advances. To provide a method of controlling a movable member in.

[0014]

According to a first aspect of the present invention, there is provided a method for controlling a movable member in a molding machine, which detects a moving speed of a movable member which is moved by a driving means of the molding machine. The overrun distance from the braking start position of the movable member is obtained by the deceleration time required for the moving movable member to stop or to decelerate to a speed close to the stop, and the overrun distance from the movement limit position of the movable member. Only before this, the braking start position of the movable member is set, and when the movable member reaches the braking start position, the drive means is switched to the braking control.

According to a second aspect of the present invention, there is provided a method for controlling a movable member in a molding machine, wherein in the control method according to the first aspect, the moving speed is detected and the overrun distance and the braking start position are calculated. It is characterized in that it is continuously repeated during the movement of.

Further, the control method of the movable member in the molding machine according to claim 3 of the present invention is the control method according to claim 1, wherein the overrun distance of the movable member is X, the moving speed is Vf, and the speed after deceleration. Is Vf0, the deceleration time required to change the moving speed from Vf to Vf0 is T, the maximum moving speed of the movable member is Vfmax, and the moving speed V is calculated from the maximum moving speed.
When the minimum deceleration time required to reach f0 is Tmin, the overrun distance X is obtained by the following equations (1) and (2). X = (Vf × T) / 2 ... (Equation 1) T = Tmin × (Vf-Vf0) ÷ (Vfmax-Vf0) ... (Equation 2)

[0017]

In the method of controlling the movable member in the molding machine according to the first aspect of the present invention, when the moving speed of the movable member is detected, it is necessary to reduce the moving speed and the moving speed to a predetermined speed. The deceleration time is used to determine the overrun distance that the movable member moves from the position where the braking control is started to the predetermined speed. Further, the most advanced position of the movable member with respect to the fixed member is set as a movement limit position, and the braking start position is set from this movement limit position to the front by the overrun distance. Then, when the movable member reaches the braking start position, braking control is started, the movable member advances from the braking start position by the overrun distance, and then is decelerated to a predetermined speed. Here, the movement limit position of the movable member is uniquely determined in the molding machine, and since the overrun distance is obtained based on the moving speed of the movable member, the overrun distance according to the moving speed is determined. Thus, the braking start position is set, whereby the movable member is surely decelerated to a predetermined speed before reaching the movement limit position.

Further, when the movable member is an injection screw, the movement limit position is set slightly frontward from the contact position with the heating cylinder through which the injection screw is inserted, and the movable member is movable. In the case of a board, it is set slightly closer to the front side than the contact position between the movable mold attached to the movable board and the fixed mold attached to the fixed board.

Further, the speed after the deceleration is set to, for example, zero or a speed at which the movable member can be stopped immediately when the movable member is the injection screw, and when the movable member is the movable platen. The speed is set so that the impact force at the time of contact between the movable mold and the fixed mold is within the allowable range.

According to a second aspect of the present invention, there is provided a method for controlling a movable member in a molding machine, wherein the calculation of the overrun distance in the first aspect is continuously performed during the movement of the movable member so that braking is performed according to a change in speed. The start position is set, whereby the braking start position is set accurately, and unnecessary braking control is prevented.

Further, in the method for controlling a movable member in a molding machine according to a third aspect of the invention, the minimum deceleration time from the maximum speed of the movable member in the molding machine to a predetermined speed is used as a reference.
The deceleration time from the arbitrary moving speed is calculated, and the deceleration time at the arbitrary moving speed is calculated based on this deceleration time. Since the calculation of the deceleration time is performed on the basis of a value (minimum deceleration time) which is almost uniquely determined by the capacity of the molding machine, the deceleration time is calculated with high accuracy. The overrun distance calculated based on this deceleration time is also calculated with high accuracy.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, prior to the description of the control method of the present invention, an outline of an apparatus in which this control is preferably implemented will be described.

In FIG. 1, reference numeral 1 indicates an in-line screw type injection molding machine (hereinafter abbreviated as an injection molding machine) to which the present embodiment is applied. The injection molding machine 1 has a product cavity (cavity). ) A fixed mold 2 and a movable mold 3 that form C, and an injection device 4 that is provided so as to be able to come into contact with and separate from the fixed mold 2 and that injects and fills the molten material into the cavity C.
And a control unit 5 for controlling the operation of the injection device 4.

More specifically, the injection device 4 is provided with a nozzle 6a, which serves as an injection hole for the molten material into the fixed mold 2, at the tip thereof, and a heating cylinder 6 for heating and melting the injection material, and this heating cylinder 6 A hopper 7 that is provided in communication with the rear end of the heating cylinder 6 for supplying the injection material into the heating cylinder 6, and the injection material that is inserted into the heating cylinder 6 from the rear side and melted in the heating cylinder 5. An injection screw 8 that injects toward the nozzle 6a and an injection ram 9a that is connected to the injection screw 8, and a hydraulic cylinder 9 that reciprocates the injection screw 8 in its longitudinal direction, and a hydraulic cylinder 9 of this hydraulic cylinder 9. The injection ram 9a is attached to the rear part
And a servomotor 1 for controlling the supply of hydraulic oil supplied to the hydraulic cylinder 9.
1 and.

The rotary shaft 10 of the hydraulic motor 10
A spline is formed on the outer periphery of a, and the rotary shaft 10a is fitted to the injection ram 9a through the spline to allow the injection ram 9a to move in the longitudinal direction. While rotating around the axis.

Inside the hydraulic cylinder 9, there is formed a pair of hydraulic chambers 13 and 14 divided in the length direction by a piston 12 formed integrally with the outer periphery of the injection ram 9a. The hydraulic oil is supplied to the chambers 13 and 14 via the servo valve 11, and
The injection ram 9a and the injection screw 8 are moved back and forth by the pressure difference of the hydraulic oil.

Further, pressure sensors 15 and 16 for detecting the pressure of the hydraulic oil in the pressure chambers 13 and 14 are attached to the outer circumference of the hydraulic cylinder 9, and a hydraulic cylinder is provided at the tip of the injection ram 9a. A position detector 17 installed outside the device 9 is connected via an operating piece 18. The operating piece 18 is projected into the space in front of the hydraulic cylinder 9 through a guide hole 19 formed in the side wall of the hydraulic cylinder 9, and the injection ram 9 is also provided.
The distal end portion of a is engaged with the injection ram 9a in a state in which the relative movement in the longitudinal direction is restrained and the relative rotation about the axis is possible.

A hydraulic pressure source 20 such as a hydraulic pump and a tank 21 for collecting the hydraulic oil discharged from the hydraulic cylinder 9 are connected to the servo valve 11.

On the other hand, the control unit 5 includes a central control unit 22 in which a control program for the entire injection molding machine 1 is stored.
And a speed control system for controlling the speed of the injection screw 8 and a pressure control system for controlling the pressure of the injection screw 8.

The speed control system calculates the speed of the injection screw 8 based on a signal from the position setting unit 23 for setting the injection speed during speed control and the position detector 17, and a feedback signal of this speed information. And a speed comparison unit 26 for comparing a speed feedback signal from the speed conversion unit 24 with a speed signal from the speed setting unit 23 or a forced brake monitor 25 described later, and a speed comparison unit 26. Based on the position signal from the speed calculation unit 27, which corrects the speed based on the comparison result in the comparison unit 26, and the position signal from the position detector 17, and according to the program given from the central control unit 22, the injection is performed. The forced brake monitor 25 for controlling the braking of the screw 8 and the forced brake monitor 25 Switching that is operated based on a signal from the arithmetic unit 25a provided and switches the input signal to the speed comparison unit 26 between the speed signal from the forced brake monitor 25 and the speed signal from the speed setting unit 23. And part 28.

Further, the pressure control system includes a pressure setting unit 29 for setting the pressure at the time of pressure control, and each of the pressure sensors 1
A differential unit 30 which is connected to 5 and 16 and outputs a signal of the injection pressure of the hydraulic cylinder 9 as a feedback signal by detecting the pressure difference between the hydraulic chambers 13 and 14;
The pressure comparison unit 3 that compares the feedback signal from the difference unit 30 with the output signal from the pressure setting unit 29.
1 and a pressure calculation unit 32 that performs pressure correction based on the result of the pressure comparison unit 31.

The speed control system and the pressure control system are switched by a switching unit 33 operated by the central control unit 22. Further, the switching unit 33 includes the speed calculation unit 27.
Also, the servo valve 11 is connected via a servo amplifier 34 that amplifies the drive signal output from the pressure calculator 32.

Next, an embodiment of the control method of the present invention will be described together with the operation of the injection molding machine 1 thus constructed.

First, while setting the injection amount of the material,
After the injection speed is set by the speed setting unit 23, the injection pressure is set by the pressure setting unit 29, and other conditions such as temperature are set, the injection material is measured.

The injection material is weighed in the same manner as in the conventional case, and is performed by applying a predetermined back pressure to the injection screw 8 by the hydraulic cylinder 9 and rotating the injection screw 8 by the hydraulic motor 10. That is, as the injection screw 8 rotates, the injection material stored in the hopper 7 is drawn into the heating cylinder 6 and fed toward the front of the heating cylinder 6, and the injection material is moved to the front of the heating cylinder 6. While being fed, it is heated and melted by the heating cylinder 6, and is stored between the tip of the inner surface of the heating cylinder 6 and the tip of the injection screw 8.

When the molten material is sent to the front of the heating cylinder 6 in this way, the pressure of the molten material gradually rises, and this pressure causes the injection screw 8 to retreat against the back pressure. In a state in which the injection screw 8 is retracted to a predetermined position, a predetermined amount of molten material is stored in the heating cylinder 6 in the front part of the injection screw 8 and measurement is performed.

Thus, the injection process is started based on the program stored in the central processing unit 22. Then, at the start of the injection process, the switching unit 28
Is held to connect the speed setting unit 23 to the speed comparing unit 26, and another switching unit 33 is held to connect the speed control system to the servo valve 11.

When the injection process is started from this, first,
Based on the speed information set in the speed setting unit 23, the servo valve 1 is transmitted from the speed calculation unit 27 via the servo amplification unit 34.
1, a drive signal is output to increase the pressure on one hydraulic chamber 14 side of the hydraulic cylinder 9, and the injection screw 8 is advanced by the injection ram 9a, so that the molten material located in front of the injection screw 8 moves in the mold. Is injected into.

In such an injection process, the moving position of the injection screw 8 is constantly detected by the position detector 17, and the actual speed of the injection screw 8 is calculated in the speed conversion unit 24 based on this position information. , The actual speed information of the injection screw 8 is the speed comparison unit 2
It is output to 6 as a feedback signal.

In this speed comparison unit 26, the target speed input from the speed setting unit 23 is compared with the actual speed fed back, and if there is a difference between these, the correction signal is given. The generated correction signal of the speed is output to the servo amplification unit 34 via the switching unit 33, amplified by the servo amplification unit 34, and then output to the servo valve 11 as a drive signal.

As a result, the injection screw 8 is advanced at the set speed, and the molten material is injected into the molds 2 and 3.

On the other hand, the position signal from the position detector 17 and the speed signal from the speed conversion unit 24 are input to the calculation unit 25a of the forced brake monitor 25, and the position signal is input to the central control unit 22. ing.

When the forward position of the injection screw 8 reaches a predetermined position, a drive signal is output from the central control section 22 to the switching means 33 and the speed control system connected to the servo amplifier 34. Is disconnected and the pressure control system is connected, whereby the injection screw 8 is shifted to pressure control.

When the pressure control is performed, a set pressure given according to the forward position of the injection screw 8 and
The comparison with the actual pressure applied to the injection screw 8 by the hydraulic cylinder 9 as detected by the pressure sensors 15 and 16 and the difference unit 30 is performed in the pressure comparison unit 31, and based on this comparison result. A correction value of the operation amount of the servo valve 11 is calculated by the pressure calculation unit 32, and the correction signal is calculated by the pressure calculation unit 32.
The output of the injection screw 8 is controlled by the servo amplifier 34 and the output to the servo valve 11.

On the other hand, as described above, the position information and the speed information of the injection screw 8 are also input to the calculation unit 25a of the forced brake monitor 25 from the position detector 17 and the speed conversion unit 24. In the portion 25a, the injection screw 8 is prevented from advancing excessively, or
Monitoring for performing braking control for mitigating impact force at the time of collision with other components is continuously performed.

That is, the computing unit 25a starts braking of the injection screw 8 based on the moving speed of the injection screw 8 and the deceleration time required for the moving injection screw 8 to stop or decelerate to a speed close to the stop. When the overrun distance from the position is obtained, the braking start position of the injection screw 8 is set to the front by the overrun distance from the movement limit position of the injection screw 8, and the injection screw 8 reaches the braking start position. In addition, the hydraulic cylinder 9 is switched to the braking control.

More specifically, in the present embodiment,
The overrun distance of the injection screw 8 is X, the moving speed is Vf, the speed after deceleration is Vf0, the deceleration time required to change the moving speed from Vf to Vf0 is T, the maximum moving speed of the injection screw 8 is Vfmax, and The minimum deceleration time required from the maximum moving speed Vfmax to the moving speed Vf0 is Tmi.
n, and the overrun distance X is expressed by the following equation 1 and 2
I try to find it by an expression. X = (Vf × T) / 2 ... (Equation 1) T = Tmin × (Vf-Vf0) ÷ (Vfmax-Vf0) ... (Equation 2)

Here, the maximum moving speed Vfmax is a speed obtained when the injection screw 8 is moved with the maximum capacity of the injection molding machine 1, and is a value which is unique to the injection molding machine 1 and is almost invariable. can get. The minimum deceleration time Tmin is the time required to decelerate from the maximum moving speed Vfmax with the maximum deceleration capacity of the injection molding machine 1 to a predetermined speed Vf0, for example, zero, and this value is also injected. It is a value specific to the molding machine 1 and is regarded as an almost invariable value.

Therefore, the ratio of the deceleration time T required for decelerating from a certain moving speed Vf to a predetermined speed Vf0 and the minimum deceleration time Tmin is, as shown in the above equation 2, the moving speed Vf and the maximum speed Vfmax. Will be proportional to the ratio of.

In this way, when the time T required to reach the predetermined speed Vf0 from the moving speed Vf is obtained, the overrun distance (that is, the distance required from the start of braking to the predetermined speed Vf0) X is 1 As shown in the equation, it is obtained as the product of this speed Vf0 and the deceleration time T.

The movement limit position of the injection screw 8 is stored in the calculation unit 25a of the forced brake monitor 25. This movement limit position is, for example, the tip of the injection screw 8 and the heating cylinder 6. It is set at a position where a minute gap is formed with the vicinity of the tip of the inner surface.

Therefore, in the calculation unit 25a, the moving speed Vf of the injection screw 8 obtained from the speed conversion unit 24 is calculated.
The overrun distance X corresponding to the moving speed Vf is sequentially calculated on the basis of the above information, and the braking start position is set based on the overrun distance X and the preset movement limit position.

Then, according to the position information from the position detector 17, when the injection screw 8 reaches the braking start position, the switching means 33 is operated by the central control unit 22, and the servo amplifying unit 34 and the speed are increased. The control system is connected and the switching unit 28 is operated by the arithmetic unit 25a.
Is operated to connect the speed comparison unit 26 and the calculation unit 25a.

From this, the calculation unit 25a to the speed comparison unit 2
A speed signal as a deceleration signal is output to 6 and braking control of the injection screw 8 is started. During such braking control, the moving speed of the injection screw 8 is controlled by the speed comparing unit 26 via the position detector 17 and the speed converting unit 24.
Is fed back to the braking control of the injection screw 8.

Since the distance from the braking start position to the movement limit position is set as the overrun distance X, the injection screw 8 is moved from the braking start position to the overrun distance X. It will be stopped later. Therefore, the injection screw 8 is surely stopped at the movement limit position, and when the predetermined speed Vf0 at this time is zero, the movement limit position is the same as that of the injection screw 8 as described above. Since it is set at a position where a gap is formed with the cylinder 6, the contact between the injection screw 8 and the heating cylinder 6 is avoided.

Further, in the present embodiment, the calculation of the overrun distance X is continuously performed corresponding to the speed of the injection screw 8. Therefore, the moving speed of the injection screw 8 is controlled by the deceleration control described above. When Vf decreases, the braking start position is gradually brought closer to the movement limit position accordingly. Therefore, when the movement limit position is reached, a predetermined speed Vf0 is set.

On the other hand, when the movement limit position is set to a position where the injection screw 8 and the heating cylinder 6 come into contact with each other or when the predetermined speed Vf0 is set to a value close to zero, the injection screw 8 is stopped by being brought into contact with the heating cylinder 6 at a very small speed.

Therefore, in any case, damage to the injection screw 8 and other components is suppressed.

Then, for example, when the injection material is measured normally, the movement of the injection screw 8 is decelerated by the pressure of the material existing at the inner front end of the heating cylinder 6 in the latter half of the pressure control, and Sufficient deceleration is performed before reaching the braking start position. As a result, when the injection screw 8 is operating normally, the braking control is not started and the molding conditions are not adversely affected.

Next, a second embodiment of the present invention will be described with reference to FIGS. In the following explanation,
The same parts as those in FIG. 1 are designated by the same reference numerals to simplify the description. The present embodiment is an example applied to the movement control of the movable mold 3 in the opening / closing operation of the molds 2 and 3.

More specifically, the fixed mold 2 is attached to a fixed platen 40 fixed to the base of the injection molding machine 1,
The movable mold 3 is a movable platen 4 slidably held by a tie bar or the like installed between the base and the fixed platen 40.
By being attached to the mold 1, the two molds 2 and 3 are held in a state of being opposed to each other so that they can approach and separate from each other.

A position sensor 42 for detecting the moving position of the movable platen 41 is connected to the movable platen 41, and the fixed platen 40 and the movable platen 41 open and close the movable mold 3 described later. The mold clamping device 43 is configured with the moving cylinder.

The cylinder which constitutes the mold clamping device 43 includes a mold clamping cylinder 45 to which a mold clamping ram 44 integrally mounted with the movable plate 41 is slidably mounted,
A fast-forward cylinder 46 provided inside the mold clamping cylinder 45, and an on-off valve 4 for controlling the supply of hydraulic oil to the mold clamping cylinder 45 and the fast-forward cylinder 46.
7, a servo valve 48, a mold opening / closing valve 49, and a control unit 50 that controls the operation of each of these valves 47 to 49.

More specifically, the mold clamping cylinder 45 has a first hydraulic chamber 45a and a second hydraulic chamber 45b defined by the mold clamping ram 44 formed therein. When the hydraulic oil is supplied to the first hydraulic chamber 45a, the mold clamping ram 44 is moved so as to project to move the movable plate 41 in the mold closing direction, and the hydraulic oil is supplied to the second hydraulic chamber 45b. By the supply, the mold clamping ram 44
Is moved so that the movable platen 41 is moved in the mold opening direction. Further, the mold clamping cylinder 45 is provided with a pressure sensor 51 for detecting the pressure of the first hydraulic chamber 45a.

The fast-forwarding cylinder 46 is provided integrally with the mold clamping cylinder 45, and the mold clamping ram 44 is slidably inserted from the rear in the mold clamping direction. A hydraulic chamber 46a is formed between them. And this hydraulic chamber 46
By supplying hydraulic oil to a, the mold clamping ram 4
4 is moved in the mold clamping direction. Also,
The volume of the hydraulic chamber 46a is formed smaller than that of the first hydraulic chamber 45a, whereby the mold clamping ram 44 is moved at a high speed by the supply of hydraulic oil to the hydraulic chamber 46a. It is like this.

The mold on-off valve 49 is connected to a hydraulic pump 54 for generating pressurized oil and a hydraulic oil tank 55 for collecting and storing the hydraulic oil discharged from the mold clamping device 43. While supplying and stopping the hydraulic oil supplied from the hydraulic pump 54 to the servo valve 48,
The hydraulic oil collected via the servo valve 48 is guided to the hydraulic oil tank 55.

The servo valve 48 is connected to the second hydraulic chamber 45b of the mold clamping cylinder 45 and the hydraulic chamber 46a of the fast-forward cylinder 46.
By selectively supplying hydraulic oil to b.46a, the mold clamping ram 44 can be reciprocated in the mold clamping direction and the mold opening direction, and the hydraulic chambers 45
The moving speed is adjusted by adjusting the balance of the hydraulic oil pressure supplied to b46a.

The on-off valve 47 connected to the servo valve 48 supplies the hydraulic oil supplied from the servo valve 48 at the time of mold clamping to the first cylinder of the mold clamping cylinder 45.
Of the hydraulic oil in the first hydraulic chamber 45a through the mold clamping cylinder 45 and the mold opening / closing valve 49 while the mold is opened.
It is supposed to lead to. When hydraulic oil is supplied to the first hydraulic chamber 45a of the mold clamping cylinder 45 by the opening / closing valve 47, the first hydraulic pressure is generated in addition to the pressing force generated in the hydraulic chamber 46a of the fast-forward cylinder 46 described above. The pressurizing force generated in the chamber 45a is applied to the mold clamping ram 44, so that the high-pressure mold clamping required for injection is performed.

The control unit 50 controls the servo valve based on the comparison between the pressure signal fed back from the pressure sensor 51 provided in the first pressure chamber 45a of the mold clamping cylinder 45 and the input pressure command. A pressure controller 56 for feedback controlling the operation of the servo valve 48; a position controller 57 for feedback controlling the operation of the servo valve 48 based on a comparison between the position signal from the position sensor 42 and the input position command; A speed converter 58 for calculating the moving speed of the movable plate 41 based on the position signal.
And a speed control unit 59 for feedback-controlling the operation of the servo valve 48 based on the comparison between the speed signal from the speed conversion unit 58 and the input speed signal, and these control units 56, 57, 59. The loop switching unit 60 that switches control and the current amplification unit 61 that amplifies each control signal output from the loop switching unit 60 are configured.

Next, a method of controlling the movable plate 41 in the mold clamping device 43 having the above-described structure will be described.

First, the mold clamping operation will be described. When this mold clamping operation is started, the loop control switching unit 60
When the speed control is selected, the open / close valve 47 is held in the OFF state and the mold open / close valve 49 is operated, the hydraulic oil supplied from the hydraulic pump 54 is guided to the servo valve 48, and By operating the servo valve 48 by a control signal from the speed control unit 59, hydraulic oil is supplied to the hydraulic chamber 46a of the fast-forward cylinder 46. As a result, the mold clamping ram 44 is moved at high speed in the mold clamping direction, so that the movable platen 41 is moved together with the movable mold 3 toward the fixed mold 2.
Then, the moving speed of the movable plate 41 is determined by the position sensor 42.
By being fed back through the speed conversion unit 58, the speed control unit 59 controls the servo valve 48 so that the moving speed of the movable platen 41 becomes the predetermined speed set by the speed command. The operation is controlled (here, as shown in FIG. 3, the case of the high-speed mold clamping 1 will be described).

When the movable platen 41 reaches the deceleration start position 1, the movable platen 4 is moved to deceleration control.
Although the deceleration of 1 is started, this deceleration control is performed under the following conditions.

That is, when the distance required for deceleration is Xmc, the current speed is Vf, the speed after deceleration is Vf0, and the time required to change from the current speed Vf to the speed Vf0 after deceleration is T, Xmc = (Vf- Vf0) ÷ 2 × T ············ (Equation 3), the distance Xmc required for deceleration is calculated, and this distance Xmc
Then, the speed reduction control starts when the relationship between the current position P and the position (which is shown as the low speed mold clamping position in FIG. 3) at which the velocity Vf0 must be satisfied satisfies the following four expressions. To be done. In other words, the position P that satisfies Expression 4 is the deceleration start position 1. P ≦ Xmc + Xs (4 formulas)

By such deceleration control, the distance Xmc required for deceleration is calculated from the current speed Vf in the middle of the mold clamping operation and the speed Vf0 after deceleration, and the distance from the position Xs which should be the speed Vf0 to the front side. The deceleration control will be started at the time when it reaches Xmc. Then, it is uniquely determined by the deceleration capability of the mold clamping device 43, and the distance Xmc required for deceleration is set to the front side based on the known values of the deceleration rate and the current speed and the target speed to be decelerated. From the above, by setting the deceleration start position 1 according to the equation (4), the movable platen 41 is surely decelerated to the speed Vf0 by the time it reaches the position Xs at which the speed Vf0 must be maintained.

Moreover, when the target speed Vf0 after deceleration and its position Xs are constant, the deceleration start position 1 is set according to the current speed Vf before deceleration start.
Therefore, the larger the current speed Vf, the larger the distance Xmc required for the deceleration, the longer the deceleration start position 1, and the smaller the current speed Vf, the shorter the distance Xmc required for the deceleration. .

That is, also in this embodiment, the movable platen 4
The deceleration start position 1 corresponding to the current speed Vf of 1 is automatically set to the optimum position, and reliable deceleration is performed at the set predetermined position. For example, as shown in FIG. 3, when the movable platen 41 is moved at a speed indicated by high-speed mold clamping 2, which is slower than high-speed mold clamping 1, the deceleration start position 2 is closer to the low-speed mold clamping position Xs. After being set, deceleration control is started from this position, and in this embodiment, deceleration is performed along the linear deceleration curve (deceleration region) A in the high-speed mold clamping 1. Thus, the reason why both deceleration curves are linear is that the deceleration rate of the mold clamping device 43 is constant and the position at which the final deceleration speed Vf0 is set is constant.

In the present embodiment, the movable plate 41 is
However, after being decelerated to the deceleration speed Vf0 described above, by further moving in the mold clamping direction at that speed,
The movable mold 3 attached to the movable plate 41 is brought into contact with the fixed mold 2 at a low speed to stop the movement thereof. The low speed moving area B is set to protect the guide pins and the like provided in the mold, and the moving distance is appropriately changed according to the type of the mold.

After the aforesaid dies 2 and 3 are brought into contact with each other, in the loop switching section 60, the control loop of the mold clamping device 43 is switched to pressure control, and the on-off valve 47 is operated. And the servo valve 4
8 and the first hydraulic chamber 45a of the mold clamping cylinder 45 are communicated with each other, so that a part of the hydraulic oil supplied from the servo valve 48 is supplied to the first hydraulic chamber 45a and then to the mold clamping ram 44. Large pressure is applied. Then, the hydraulic oil pressure in the first hydraulic chamber 45a is measured by the pressure sensor 51.
The mold clamping pressure of both molds 2 and 3 is controlled by controlling the operation of the servo valve 48 based on the control signal output from the pressure control unit 56 while being fed back to the control unit 50 via. Feedback controlled.

Further, in order to make the above-mentioned transition from the deceleration area A to the low speed movement area B more smoothly, it is also possible to make an S-shaped deceleration curve as shown by the curve C in FIG. .

The control method of the present invention is also applied when the movable mold 3 shown in this embodiment is opened. The mold clamping device 43 is in the high-pressure mold clamping state as shown in FIG.
Is operated to balance the pressure in the mold closing direction and the pressure in the mold opening direction that act on the mold clamping ram 44, so that the first hydraulic chamber 45a of the mold clamping cylinder 45 can be balanced.
And the hydraulic fluid in the hydraulic chamber 46a of the fast-forward cylinder 46 is gradually discharged to the hydraulic fluid tank 55 through the mold opening / closing valve 49, so that the mold clamping pressure is removed (indicated as a pressure release region D in FIG. 4). Indicated). This pressure release operation is also the first
Based on the pressure signal from the hydraulic chamber 45a, the pressure control unit performs feedback control.

After completion of such depressurization, the servo valve 48 is actuated again to supply hydraulic oil to the second hydraulic chamber 45b of the mold clamping cylinder 34 and at the same time to the first hydraulic chamber 45a. By discharging the hydraulic oil in the hydraulic chamber 46a of the fast-forward cylinder 46 to the hydraulic oil tank 55, the mold clamping ram 44 is moved to a predetermined position at a low speed in the mold opening direction (this low speed mold opening region is shown in FIG. To E).

Furthermore, after the movable plate 41 is moved to a predetermined position at a low speed, the amount of hydraulic oil supplied to the second hydraulic chamber 45b by the servo valve 48 is increased, so that the high speed type shown in FIG. The mold is opened while being accelerated to the speed of opening 1, and at the speed of the high speed mold opening 1,
Mold opening is continued.

Then, when the movable platen 41 reaches the deceleration start position 1, deceleration is started and the movable platen 41 is stopped when the movable platen 41 reaches the movement stop position, that is, the mold opening stop position Xms. .

When the deceleration start position 1 of the movable plate 41 is Vf for the current speed in the high speed mold opening 1, Xmo is the distance required to stop from the current speed Vf, and T is the time required for stopping, It is calculated by the following (Equation 5). Xmo = Vf ÷ 2 × T (5 formulas)

Then, assuming that the current position is P and the position at which the movement of the movable plate 41 is stopped is Xms, the current position P is
When the following (6) is satisfied, the deceleration start position 1 is set. P ≧ Xms-Xmo (6 equations)

That is, deceleration is started at the time when the distance Xmo required for stopping in the mold opening direction is reached from the preset stop position. Here, since the deceleration start position 1 is determined based on the current speed Vf, the movable platen 41 is surely set to the set stop position regardless of the moving speed thereof for the same reason as the mold closing operation. To be stopped. Further, even in such a stop operation, the linear deceleration processing as shown by F in FIG. 4 and the S-shaped deceleration processing as shown by G in FIG. 4 are possible.

As described above, in this embodiment, the mold 2
Even when the opening / closing operation of 3 is performed, it is possible to reach or stop at a predetermined speed at a predetermined position, so that not only high cycle molding is possible, but also at the time of mold closing, collision of the mold and guide pin Damage and the like are prevented, and it is not necessary to manually set the deceleration start position, which improves operability. Furthermore, when opening the mold,
Since the stop position of the movable mold 3 is carried out with high accuracy, the positional relationship with the take-out machine for taking out the molded product is accurately set, and its adjustment becomes easy.
In addition, molding troubles due to poor takeout are eliminated.

The above embodiment is an example, and can be variously changed according to the type of injection molding machine or the type of movable member to be applied, or the design requirements. For example, the example in which the hydraulic cylinder 9 is used as the driving means for the injection screw 8 and the movable plate 41 has been shown, but the invention is not limited to this, and an injection molding machine using a ball screw mechanism or an electric driving means as the driving means. It is also applicable to.

[0089]

As described above, according to the first aspect of the present invention.
The method of controlling the movable member in the molding machine described above is based on the moving speed of the movable member and the time required to decelerate the moving member to a predetermined speed. The braking start position is set before the overrun distance from the movement limit position of the movable member, and the braking control is started when the movable member reaches the braking start position. It has an excellent effect.

By starting the braking at the time when the movable member reaches the braking start position, the movable member is moved to the predetermined limit at the time when the movable member is moved by the overrun distance from the braking start position, that is, when the moving limit position is reached. Can be decelerated to the speed of. Then, the movable limit position is set slightly before the contact position between the movable member and the fixed member, and the predetermined speed is set to zero so that the movable member is stopped before the contact with the fixed member. Alternatively, or by setting the predetermined speed to a value close to zero, the movable member can be sufficiently decelerated before the movement limit position to sufficiently reduce the speed at the time of collision with the fixed member. it can. Also, when the movement limit position of the movable member is set to the contact position with the fixed member,
If the speed after deceleration is set to zero or a speed close thereto, the contact speed between the movable member and the fixed member can be made sufficiently small.

Therefore, the contact between the movable member and the fixed member is avoided, or the impact force at the time of collision between the movable member and the fixed member is relaxed by sufficient deceleration of the movable member. It is possible to prevent damage to the members. Moreover, since the above-mentioned braking start position is set according to the moving speed of the movable member, the braking start position according to the magnitude of the moving speed is accurately set,
Regardless of the moving speed, reliable deceleration or stop can be performed before reaching the above-mentioned movement limit position. Therefore, problems such as a setting error of the braking start position will not occur.

Since the deceleration time and the overrun distance are set almost uniquely by the capability of the injection molding machine, the above-mentioned setting of the braking start position can be performed with high accuracy.

Moreover, since it is possible to extend the start of braking to the last minute position, not only is it possible to perform high cycle molding, but also when it is applied to the mold opening operation of a movable mold as a movable member, for example. By controlling the stop position of the movable mold with high accuracy, it is possible to set the positional relationship between the take-out machine and the movable mold at the time of taking out the product with high accuracy, which facilitates adjustment of the take-out machine. In addition, it is possible to eliminate the molding trouble due to the poor take-out.

According to the method for controlling a movable member in a molding machine according to a second aspect, the moving speed detection, the overrun distance calculation, and the braking start position calculation according to the first aspect are performed by moving the movable member. By performing the operation continuously during the middle, the braking control can be performed according to the operating condition of the molding machine, whereby the braking start position is set accurately and unnecessary braking control is prevented. To be done.

Further, according to the control method of the movable member in the molding machine, the deceleration from an arbitrary moving speed is performed with the minimum deceleration time from the maximum speed of the movable member in the molding machine to the predetermined speed as a reference. Since the time is obtained and the deceleration time at the arbitrary moving speed is obtained based on this deceleration time, the deceleration time of the deceleration time is determined based on a value (minimum deceleration time) almost uniquely determined by the capacity of the molding machine. By performing the calculation, it is possible to calculate the deceleration time with high accuracy. In addition, since the overrun distance and the braking start position are calculated based on this deceleration time, it is possible to similarly calculate them with high accuracy. Therefore, the control method for the movable member according to the first aspect can be preferably implemented.

[Brief description of drawings]

FIG. 1 is a control block diagram of an injection molding machine for preferably implementing one embodiment of the present invention.

FIG. 2 shows a second embodiment in which the present invention is applied to the opening / closing operation of a mold, and is a control block diagram of a mold clamping device.

FIG. 3 is a diagram showing a relationship between speed and pressure and position when a movable platen is closed in a second embodiment of the present invention.

FIG. 4 is a diagram showing the relationship between speed and pressure and position when the movable plate is opened in a mold according to the second embodiment of the present invention.

[Explanation of symbols]

 1 Injection Molding Machine 2 Fixed Mold 3 Movable Mold 4 Injection Device 5 Control Unit 6 Heating Cylinder (Fixed Member) 8 Injection Screw (Movable Member) 9 Hydraulic Cylinder (Drive Means) 11 Servo Valve 15 Pressure Sensor 16 Pressure Sensor 17 Position Detector 23 Speed setting unit 24 Speed conversion unit 25 Forced brake monitor 25a Calculation unit 26 Speed comparison unit 27 Speed calculation unit 41 Movable plate 42 Position sensor 43 Clamping device 47 Open / close valve 48 Servo valve 49 Type open / close valve 50 Control unit 56 Pressure Control unit 57 Position control unit 58 Speed conversion unit 59 Speed control unit

Claims (3)

[Claims] 1. A moving speed of a movable member moved by a driving unit of a molding machine is detected, and the moving speed and a deceleration time required for decelerating the moving movable member to a speed at which the moving member is stopped or close to the stopped speed are detected. , The overrun distance from the braking start position of the movable member is determined, and the braking start position of the movable member is set to the front side by the overrun distance from the movement limit position of the movable member. The method for controlling a movable member in a molding machine is characterized in that the drive means is switched to a braking control when the temperature reaches a predetermined value. 2. The method for controlling a movable member in a molding machine according to claim 1, wherein the detection of the moving speed and the calculation of the overrun distance and the braking start position are continuously repeated during the movement of the movable member. . 3. The overrun distance of the movable member is X, the moving speed is Vf, the speed after deceleration is Vf0, and the moving speed is from Vf to V.
When the deceleration time required to reach f0 is T, the maximum moving speed of the movable member is Vfmax, and the minimum deceleration time required to reach the moving speed Vf0 from this maximum moving speed is Tmin, the overrun distance X is The method for controlling a movable member in a molding machine according to claim 1, wherein the following equation is obtained. X = (Vf × T) / 2 ... (Equation 1) T = Tmin × (Vf-Vf0) ÷ (Vfmax-Vf0) ... (Equation 2)