JPS6228221A - Controlling device in injection molder - Google Patents

Abstract

PURPOSE:To perform precise resin molding by a method wherein digital control valves which control flow rate and pressure by pulse signals are provided in a circuit for controlling the mold closing, mold opening, injection, back pressure, ejector, advancement of an nozzle and the like of a molder by means of oil hydraulic force. CONSTITUTION:Signals which determine the mold closing, mold opening, injection, back pressure, ejector, advancement of an nozzle and the like are successively sent from a sequence controlling part 33 to the respective setting circuits in a speed. Here digital control valves 3, 7 and 22 are controlled in response to the process signals of the respective parts of a molder and the respective command signals which are obtained by comparing the position signals sent from the acting position detectors of the respective parts of the molder with the values set at a position setter. As a result, the more carefully thought-out and precise controlling of speeds and pressures in the respective processes of the molder is done as compared with the controlling performed with electromagnetic proportional control valves.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention is an injection molding machine that uses hydraulic pressure to control mold closing, nozzle advancement, injection, supply, nozzle retraction, mold opening, ejector forward and backward movement processes, etc. This invention relates to a control gIJ device.

"Conventional technology" Conventionally, hydraulic circuits have been used to control the mold opening/closing speed during the mold opening/closing process,
When controlling mold clamping pressure, injection speed, injection pressure, etc. during the injection process, each control valve is controlled using a proportional solenoid flow control valve and a proportional solenoid pressure control valve built into the hydraulic circuit. By changing the amount of electricity (ft) applied to each step, the speed and pressure in each process are changed stepwise.

"Problems to be Solved by the Invention" However, in the conventional proportional electromagnetic flow control valve or pressure control valve described above, the position of the spool of each control valve must be moved in accordance with the applied electricity flK. However, since the speed and pressure in each process are controlled, the speed, pressure rise, and fall characteristics when changing the speed or pressure are changed individually for each process. The problem is that it is difficult to

In addition, each of the conventional control valves described above has a power ratio of 1! The structure determines the flow rate or pressure by balancing the output with the spring force of the spring installed in the valve.
It is affected by disturbance factors such as fluctuations in oil temperature, room temperature, and power supply voltage.
There are problems with poor control performance, such as speed and pressure fluctuations.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to improve the repeatability during continuous molding under the influence and sensitivity of disturbance factors such as fluctuations in oil temperature, room temperature, and power supply voltage. In addition, the characteristics (rise and fall) can be changed arbitrarily when changing each process and when changing speed or pressure in each process, and fine-grained injection molding control is possible. An object of the present invention is to provide a control device for use in a computer.

"Means for Solving the Problems" In order to achieve the above object, the present invention provides a hydraulic circuit that controls mold closing, mold opening, injection process, etc., by using a pulse signal to control the hydraulic circuit. The RTH machine is equipped with a digital control valve to control the flow rate or pressure.

"Function" In the control device of the present invention, the digital
By changing the number of pulses applied to the control motor of the digital control valve and the pulse sending speed, the flow rate or pressure of oil flowing through the digital control valve can be manipulated to control the speed or pressure of each process during injection molding. control.

"Embodiment" Hereinafter, a first embodiment of invention X will be described based on FIGS. 1 to 6.

1 in the figure is a motor 42, which is a hydraulic pump that is driven;
The suction end of this hydraulic pump l has 4 tanks of oil OT, and the discharge end has a digital flow control valve 3 and a
The valves 4 are connected to each other.

This digital flow control valve 3 has a stepping motor 45.
The number of pulses applied to and the feed rate of the pulses control the flow rate of the oil flowing into the valve and the speed at which the value reaches the value at the crotch of the flow rate. In the meantime, as the number of pulses increases from 50 pulses: fl' to 250 pulses, as shown in FIG.
There is a relationship in which k (t/m1n) increases along the M line. In addition, at the suction end of the digital flow control valve 3,
A first digital pressure control valve 7, a relief valve 8, and one end of a throttle valve 9 are each connected via a pilot pipe 6. This first digital pressure control valve 7 controls the oil pressure in the circuit and the speed until the pressure reaches the set value by applying Luhalus a to the stepping motor 10 and the feed rate of its pulses. As shown in Figure 3, there is a relationship between the above pulse number and pressure, in which the pressure (kLj/crn2) increases linearly as the pulse number cools from 50 pulses to 250 pulses. There is. Furthermore, the discharge end of the digital flow control valve 3 is connected to the other end of the throttle valve 9, and the drain and leakage of the digital flow control valve 3 is connected to the oil tank O.
T is connected. Furthermore, at the discharge end of the digital 2R,i starvation valve 3, a solenoid valve 11 for switching mold opening/closing, a solenoid valve 12 for switching forward and backward movement of the ejector, and a solenoid valve 1 for self-returning.
3, an injection/supply switching solenoid valve 14, a nozzle forward/backward switching solenoid valve 15, and other actuators 41AI are connected, respectively. These X outlet valves 11, 12,
Reference numeral 14.15 denotes an ABR recessed four-boat three-position solenoid valve, and A and B on the load side of each solenoid valve 11.12 are the piston-side ends and rods of the clamping cylinder 16 and ejector cylinder 17, respectively. Side edges (left and right edges in Figure 1)
and a solenoid valve 1 for switching forward and backward movement of the nozzle.
5, load side boats A and B, nozzle forward and backward movement cylinder 18
rod side end and piston side end (left and right 1 in Figure 1)
) are connected to each other. The load side boats A and B of the injection and supply switching solenoid valve 14 are respectively connected to the rotary hydraulic motor 419 of the valve 11 and the piston side end of the injection cylinder 20 (the right end marked with ^ in Figure 1). At the same time, a second digital pressure control valve 22 operated by a stepping motor 21 is connected to the return port RK of the solenoid valve 14 .

This second digital pressure control valve 22 has the same structure and characteristics as the first digital pressure control valve 7 described above. Furthermore, the selfless retraction solenoid valve 3 is connected to the rod side end (the left end in FIG. 1) of the injection cylinder 17 and the cylinder 20.

The mold clamping cylinder 16 is fixed to one end side (the left end side in FIG. 1) of an end plate 24 that stands up on the base 23, and the tip of the piston rod 16a of the mold clamping cylinder 16 is The end plate 24 is completely penetrated and connected to the center of the toggle mechanism 25. The left and right ends of the toggle mechanism 25, which are branched upward and downward, are connected to an end plate 24 and a movable plate 26, respectively, and are toggled by moving the piston rod 16a of the mold clamping cylinder 16 back and forth (extending and contracting). A movable platen 26 is supported by a guide shaft (not shown) via a mechanism 25, and is configured to reciprocate in the horizontal direction. In addition, the movable plate 2
A fixed platen 27 is erected on the base 23 on the opposite side of the end plate 24, facing the movable platen 2.
6 is a toggle mechanism 25 due to the advancement of the mold clamping cylinder 11 cylinder 16.
The movable mold 26a and the fixed platen 27& are sandwiched together to generate mold clamping force, and a cavity (gap) 28 is formed inside by both molds 26a and 27a. The ejector cylinder 17 is mounted on the surface of the movable platen 26 opposite to the surface on which the movable mold 26a is attached.
is fixed, and by advancing the piston rod 17a of the ejector cylinder 17, the tip of the piston rod 17a penetrates the movable platen 26 and the movable mold 26a and pushes the molded product inside the movable mold 26a outward. It is designed to stick out. , the upper part of the injection cylinder 29 has the injection cylinder 2
A hopper 30 for supplying resin is disposed inside the housing 9 . A screw 31 is filled with oil inside the injection cylinder 29, and the base end of the screw 31 is connected to the rotation @19a of the screw rotation hydraulic pressure 7-da iris 9. Furthermore, the piston rod 20a of the injection cylinder 20 is connected to the end of the rotating hydraulic motor 19 opposite to the rotating shaft 19a, and the piston rod 20a of the injection cylinder 20 is moved back and forth. By progressing,
The screw 31 is configured to reciprocate horizontally through the screw rotation hydraulic motor 19. The injection cylinder 29 and the injection cylinder 20 are connected to a connecting member 32.
The base end of the injection cylinder 2o is connected to the tip of the piston rod 19a of the nozzle forward/backward cylinder 18 fixed to the base 23, and the piston rod is connected to the base end of the injection cylinder 2o. By moving forward and backward 18a, the injection cylinder 20 and the screw +7 rotation hydraulic motor I9 are
At the same time, the injection m29 moves back and forth in the horizontal direction.

Each solenoid a of the mold opening/closing switching solenoid valve 11.

b, each solenoid a, h of the solenoid valve 12 for forward/reverse switching of Nijiev 4, solenoid b of the solenoid valve 13 for the removal of iWu, each solenoid a, b of the solenoid valve 14 for injection/supply switching, Nozzle @ for reverse switching? Each solenoid a of the tm valve 15,
b shows the general sequence of the injection molding process (hand i'i
) is inputted to each excitation signal Sl to S9 of the sequence jlilj(2) section 33.

In addition, the sequence control unit 33 outputs mold closing, mold closing speed change, nozzle advance, injection, injection first speed change, injection second speed change, supply, internal pressure removal, nozzle retreat, mold opening, mold turning speed, and Nijiev 4 forward movement. , ejector retraction, mold closing 1. Directive No. 41 810 for father pressure, mold closing second transformer pressure, injection first transformer pressure, and injection second transformer pressure
~826 are the speed and pressure control device 34 speed and pressure control device 34, respectively.
The pressure setting selection section 35 is configured to input the pressure setting selection section 35.

As shown in FIG. 4 and FIG. 5, the speed/pressure setting selection section 35 has the first speed/pressure setting selection section 35 set by overloading the 13 setting circuits 36a to 36m. 2nd mold closed, nozzle advanced, w, 1%
42, 3rd injection, supply, internal pressure removal, nozzle retreat, 1st,
The speeds (number of pulses) of the 2nd type open, Nizhiev and evening forward and backward advances and the feed speed of those pulses. Speed setting selection section 36 selected by selection circuit 36+u according to each command signal 5IO-822VC
and the pressure (number of pulses) of the 1st % section 2 type closing, 1st, 2nd, and 3rd injection circuits set in advance in the 6-even setting circuits 37a to 37f, and the feeding speed of the pulses of S. Is it IMi's Pulse i? 1 pulse feed rate and the above-mentioned command signals SI0.812°S+3. inputted via the input interface 39\i-. S16. S17.5I8j
S19. S21°522 (output signal SA in FIGS. 4 and m5) and the pressure setting selection section 37 that selects the pressure setting by the selection circuit 37g1cb in accordance with the above command signals 823 to 826 inputted via the input interface 40; It is composed of a back pressure and pulse sending speed setting circuit 38 that outputs back pressure (number of pulses) and pulse sending speed in accordance with the command signal 816 (output signal SB in Figures 4 and 5). There is. And each setting selection section 36.37
The pulse signals output by the selection circuits 36n and 37g and the back pressure and pulse transmission speed setting circuit 38 respectively drive the stepping motors 45, 10, and 21.
It is input to the drive control circuits 41, 42, 43, and these three motor drive control circuits 41, 42, 43,
A digital control valve drive control section 44 of the speed/pressure control device 34 is configured.

Next, the operation of the control device in the injection molding machine configured as described above will be explained.

First, prior to operation of the injection molding machine, each setting circuit 36a to 36m of the speed setting selection section 36 shown in FIGS.
Predetermined values are set in advance in each of the setting circuits 37a to 37f of the pressure setting selection section 37 and the back pressure and pulse feed speed setting circuit 38 (.

Next, the injection molding process is performed continuously, and one cycle of the process will be described in detail based on the operation chart shown in FIG.

At the start of one injection molding process, the sequence control unit 33
When the mold closing command signal SIO is output to the full speed/pressure control device 34, the mold closing command signal 810 inputted to the speed setting selection section 36 via the input interface 39 causes the selection circuit 36n to select the setting circuit. 36aK Since the number of pulses corresponding to the set writing brush closing speed is output to the motor 4 drive control circuit 41 at the set interval (pulse sending speed), the digital flow rate is controlled by this motor drive control circuit 41. The stepping motor 45, which controls the opening degree of the control valve 3, performs an angular fart based on the set number of pulses at a rotational speed corresponding to the set pulse sending speed. As a result, the digital flow control valve 3
At the opening speed of the valve corresponding to the pulse feed speed, the valve is opened to the opening degree corresponding to the number of pulses. This mold closing command signal SIO causes the selection circuit 37g to switch to the setting circuit 3.
The number of pulses corresponding to the first mold closing pressure set to 7aK,
The stepping motor lO, which controls the first digital pressure control valve 7 by the motor drive control circuit 42, outputs the output to the motor and drive unit control circuit 42 at set intervals (pulse feed speed). At a rotational speed corresponding to the set pulse feed speed, C is rotated the number of times based on the number of pulses set above. As a result, the first digital pressure control valve 7 changes at a rate corresponding to the pulse feed rate until the set pressure differs from the pressure corresponding to the number of pulses. In addition, the sequence control calm part 33
outputs the mold-closing command signal SIO, and also outputs an excitation signal S for energizing the lenoid a of the green open/close switching solenoid valve 11.
l'f! :The solenoid valve 11 is switched and the pressure oil is applied to the piston side end of the mold clamping cylinder I6 (the left side in FIG. 1), and the digital flow rate control valve 3 and the first digital pressure control are output. Wa? Piston rod 16a for Syrinta River 6
moves forward to bring the movable kh plate 26 connected to the tip of the piston rod 16a via the toggle mechanism 25 closer to the fixed plate 27 side. Therefore, until the movable mold 26a attached to the movable platen 26 reaches the first mold closing speed and pressure,
The fixed mold 2 is attached to the fixed plate 27 at an increasing rate of mold closing speed and mold closing pressure according to each of the pulse feed speeds used above.
7a, and when the first mold closing speed and pressure are reached, the mold closing speed and mold closing pressure are maintained and the mold approaches the solid eagle mold 27a at the shape 7c, -.

Next, when the sequence control section 33 outputs the mold closing shift command signal Sll instead of the mold closing command signal 310 to the speed/pressure control device 34, the corresponding input to the speed setting selection section 36 via the input interface 39 is Directive (N9t
S l l causes the selection circuit 36n to select the setting circuit 36
The number of pulses corresponding to the type 2 closing speed is output to the motor drive control circuit 41 (7) at the set rL81 interval (pulse sending speed). The @ff1l control circuit 41 controls the stepping mode <5 as described above, and the digital flow i-dissection valve 3 has a closing speed of 9 valves corresponding to the above-mentioned pulse feed rate, and corresponds to the above-mentioned number of pulses. Close to the opening degree. Therefore,
The movable type 26a changes from the Ll type closing speed to the second type closing speed,
i constant t, 9 deceleration at a rate according to the above pulse sending speed,
When the second mold closing speed is reached, it approaches the fixed mold 27a while maintaining this speed ((note that the speed can be increased depending on the settings).

Further, the sequence control section 33 transmits the mold closing first transformation command signal S23 to the speed/pressure ff11. When output to the I-sealing device 34, the command signal 823 causes the selection circuit 37g to
However, the number of pulses corresponding to the set second mold closing pressure is sent to the setting circuit 371) at the set interval (pulse sending speed).
Since the motor is outputted to the drive sterilization circuit 42, the first digital pressure control valve 7 is controlled by the motor drive control circuit 42, and the movable mold 26a is controlled from the first mold closing force to the first The mold closing pressure is reduced at a rate according to the set pulse feed speed 9 until mold 2 closing pressure is reached, and when the mold 2 closing pressure is reached, this pressure is maintained (note that the pressure can be increased depending on the setting). .

Next, the movable mold 26a comes into close contact with the fixed mold 27a, and the sequence system @N! I33 is the mold closing second transformation command signal S24
When the command signal 824 is outputted to the speed/pressure control device 34, the selection circuit 37g selects the setting circuit 37f.
Since the number of pulses corresponding to the set circuit pressure is output to the motor drive control circuit 42 at the set pulse sending speed, the first digital pressure control valve 7 is operated and the movable type 26a# 'i, from the second mold closing pressure to the circuit pressure,
The mold clamping force is increased at a rate of 9 in accordance with the pulse feed speed, and when the circuit pressure is reached, the mold clamping force is maintained at 9 in proportion to the circuit pressure, so that the movable mold 26a is in close contact with the fixed mold 27a. It is firmly fixed in the following state.

Subsequently, the sequence control unit 33 sends the nozzle advance command signal S12 to the speed/pressure control device [34] and the excitation signal S8.
are output to the solenoid a of the nozzle forward/backward switching solenoid valve 15, the number of pulses corresponding to the nozzle advance speed set in the setting circuit 36cK is output to the motor drive control circuit 41 at the set pulse feed speed, and Pressure oil is supplied to the piston side end of the nozzle forward/backward moving cylinder 18 through the electromagnetic valve 15, so that the injection cylinder 20 connected to the tip of the piston rod 18a of the nozzle forward/backward moving cylinder 18 and the injection cylinder The injection cylinder 29 fixed to the injection cylinder 20 via the connecting member 32 is connected to the fixed m27 side together with the screw rotating hydraulic motor 19 connected to the tip of the piston rod 20a of the injection cylinder 20. Until the nozzle forward speed is reached, the moving speed is increased in a layout corresponding to the above-mentioned pulse feed speed while approaching. If the moving speed of the injection tube 29 is different from the nozzle advance speed corresponding to the number of pulses, the injection tube 29 approaches the fixed platen 27 while maintaining this speed.

Then, the tip nozzle 298 of the injection cylinder 29 is fixed to the fixed type 27a.
When it comes into close contact with the injection inlet of
outputs the injection command signal S13 to the speed/pressure control device 34 and the excitation signal S7 to the solenoid b of the injection/supply switching solenoid valve 14, so that each setting circuit 36.
The number of pulses corresponding to the first injection speed and first injection pressure set in i, 37C is output to each motor 4 drive restraint circuit 41, 42 at each set pulse feed speed, Pressure oil is supplied to the narrow end of the piston of the injection cylinder 20 via the electromagnetic valve 14 . Therefore, the injection sheet 11
When the piston rod 20a of the cylinder 20 moves forward, the screw 31 connected to the piston rod 20a via the screw 11 rotary hydraulic motor 419 moves the inside of the injection cylinder 29 into the first injection mode corresponding to each of the above-mentioned pulse numbers. While the speed and pressure are reached, the injection station and Ω1 output pressure are increased at a rate corresponding to the above-mentioned respective pulse feed speeds while advancing,
When the injection speed and r% pressure of the screw 31 reach the above-mentioned injection speed and pressure, the screw 31 advances inside the injection cylinder 29 while maintaining this speed and pressure. The plasticized resin inside the mold begins to be supplied to the cavity [28].

Next, the sequence control section 33 controls the speed and pressure control device 3.
4, each command signal S14°825, Si2
．． S26, those command signals S14. S2
5. Through S15 and 326, the selection circuit 36n applies the number of pulses corresponding to the second and third injection speeds set in each setting circuit 36θ and 36f to the motor and drive control circuit 41 at the set pulse feed speed. (When the 1st and 2nd speed change commands for injection No. 314.S15 are output), pulse collection corresponding to the 2nd and 3rd injection pressures set in each setting circuit 37d and 37e, and the set Motor charging gIj: J19 is output to the control circuit 42 at the bar & gas feed speed (injection 1.2nd voltage transformation command signal S 25 , 52f3
(at the time of output). Therefore, the displacement degree of the screw 31 increases from the first injection speed to the second injection speed and from the second injection speed to @3 injection speed at the rate set at each pulse sending speed.
．． When the second and third injection speeds are maintained for a predetermined period of time, the injection pressure changes from the first injection pressure to the second injection pressure @3 injection pressure at the rate set at each of the above pulse feed speeds. Since each injection pressure is maintained for a certain period of time (the pressure may be increased depending on the setting), the resin is smoothly supplied into the mold and the pressure is maintained. - Furthermore, the sequence control unit 33 controls the speed/pressure control system@
When a supply command signal S16 is outputted to each setting circuit 361. , 37 f.
, 3B, all pulse numbers corresponding to the supply speed wave, circuit pressure, and back pressure are output to each motor 47 movement control circuit 41, 42, and 43 at the set pulse feed speed, so it is a digital signal. The type flow control side valve 3 and the first and second digital type upper blade control valves 7 and 22 are manufactured. Nine, the above solenoid valve 1
4 is switched, the forward movement of the screw 31 by the injection cylinder 11 and the cylinder 20 is stopped, and the screw rotation hydraulic motor '319 is rotated, and the resin is supplied from the hopper 30 to the inside of the injection cylinder 29 for plasticization. will be started. In this case, each of the control valves 3.7 controls the flow rate according to the change rate of the flow rate and pressure corresponding to each of the pulse feed speeds while the hydraulic oil reaches the flow rate and pressure corresponding to each of the above pulse numbers. Since the flow rate and pressure are controlled to increase and maintain these values when they reach predetermined values, the screw 31 inside the injection cylinder 29 initially increases the rotational speed at a certain rate. After that, a certain [C! Rotate while maintaining the full J rotation number. Then, the screw 31 rotates, and as the resin is supplied into the injection cylinder 29 and becomes faster, the screw 31 retreats. Since the piston rod 20a of the injection cylinder 11 and the cylinder 20 are connected via the injection cylinder 11, the piston rod 20a moves back f as the screw 31 moves back.

Due to this retreat of the piston rod 20&, hydraulic oil is discharged from the piston side end (right chest in Fig. 1) of the injection cylinder 20 to the injection/supply switching solenoid valve! 4 each boat B, Re
through the fx2 digital pressure control valve 22. At this time, the second digital pressure control valve 22 is controlled by the back pressure (number of pulses) and pulse feed speed set in the back pressure and pulse feed excursion setting circuit 38, so that the second digital pressure control valve 22 is set to the nine back pressures. The back pressure increases at a rate corresponding to the set value of the pulse feed rate, and when the predetermined back pressure is reached, the back pressure is maintained. As a result, the back pressure prevents the screw 31 from retreating, and the state of resin crosstalk within the f injection cylinder 29 is maintained constant.

Subsequently, the sequence control unit 33 fully outputs the internal pressure removal command signal S17 to the speed/pressure control device 34, demagnetizes the solenoid a of the magnetic valve 14 at °7 for injection/supply switching, and demagnetizes the solenoid a for self-returning. When the excitation signal S5 is output to the solenoid b of the solenoid valve 13, the number of pulses corresponding to the internal pressure removal speed set in the setting circuit 36h is set by the command signal S17, and the motor and drive are controlled at the pulse feed speed. At the same time as being output to the circuit 41, pressure oil is supplied to the mouth rad (11) of the injection cylinder 20 via the solenoid valve 13.
1Jil! (Left end in Figure 1) IC is supplied.

Therefore, the screw 31 increases its speed at a rate corresponding to the pulse feed speed until it reaches the internal pressure removal speed corresponding to the number of pulses, without rotating, and when the set internal pressure removal speed is reached. , and retreat while maintaining the internal pressure removal rate. In this case, the second digital pressure control valve 22 is not in operation because no control signal is input to it.

Next, after the internal pressure has been removed, the sequence control unit 33 sends a nozzle retreat command signal S to the speed/pressure control device 34.
18'jt output, demagnetizes the solenoid b of the heat transfer/backward solenoid valve 13, and demagnetizes the solenoid b of the nozzle forward/backward switching solenoid valve 1.
When a signal S9 is output to energize solenoid B in place of solenoid 5, the number of pulses corresponding to the nozzle retraction speed and circuit pressure set in each setting circuit 36i and 37f is changed by the command number S18. Pressure oil is outputted to each motor drive control circuit 41, 42 at a set pulse feed rate, and is also supplied to the rod end of the nozzle forward/backward movement cylinder 18 via the electromagnetic valve 15.

Therefore, the injection '? tJ29 is a screw rotation hydraulic motor 19 and an injection cylinder 20.
At the same time, the backward speed is increased by ↓9 at a predetermined rate until it reaches a constant backward speed, and when the constant backward speed is reached, that speed? i- Retreat in a maintained position and move away from the +N fixed form 27a.

Additionally, the sequence ffi'! '! ``The first part 33, for the speed/pressure control device 34, ,''! ! ! Next, the mold opening, mold-pressure transformation, ejector advance, Nijif 4 advance/retreat command signal SI9~S22 fC are output, and at the start of the mold opening process, the solenoid r of the solenoid valve 15 for switching the nozzle forward and backward movement is output.
Fully demagnetize, and fully output signal S for energizing solenoid B instead of N for mold opening/closing switching and solenoid B of solenoid valve 1,
Also, at the start of the ejector forward process, the excitation signal S2 is turned off. +: An excitation signal S3 is output to the solenoid 8 of the forward switching solenoid valve]2, and furthermore, an excitation signal S4 is output to the solenoid b of the solenoid valve I2 in place of the excitation signal S3 at the start of the ejector retraction process. Therefore, at the start of the mold opening process, the start of mold opening transformation, the start of ejector forward movement, and the start of ejector backward movement, the 1% second mold opening speed and the ejector forward and backward movement speed set in each setting circuit 313j to 36m1C are set. The digital flow Ω control valve 3 is controlled by the number of pulses and the pulse feed rate that have been set, and at the start of the mold opening process and when the ejector starts moving back and forth, pulses corresponding to the circuit pressure set in the setting circuit 37f are generated. The digital pressure control P7 is controlled by the number and pulse feed rate. As a result, at the start of the mold opening process, the piston rod 16a of the mold clamping cylinder 16 retreats, causing the movable platen 26 to reach the first mold opening speed corresponding to the pulse set above. The mold is opened at a rate corresponding to the feed speed (the total is increased), and when the first mold opening speed is reached, the fixed platen 2 is opened while maintaining that speed.
7η to get away from the car 91 again! When the opening speed is ψ, the mold opening speed is decreased at a predetermined rate from the first mold opening speed to the second mold opening speed. (Depending on the settings, the speed can also be increased). Furthermore, when the ejector starts advancing and retreating, the piston rod 17 of the ejector cylinder 17
a i Move forward and backward to project the circular molded product of the movable mold 26a to the outside. In this case, the forward and backward speeds of the piston rod 17a and the rise characteristics of the forward and backward speeds can be set individually (by the control valve 3) in the same way as each process operation, so the ejection process of the molded product is smooth and quick. It will be held in When the piston rod 17a of the ejector cylinder 17 retreats to the predetermined position 1, one cycle of the injection molding process is completed.

By continuously repeating the above-mentioned steps, a large number of molded products can be smoothly taken out. In this case, each zero constant circuit 36a to 36+n, 37a to 3
The number of pulses and pulse feed speed set in 7f and 38 are sequentially output from the sequence system 33. It is selected according to each command signal SIO to S26 generated by a combination of the process signal of each part, the operating position of each part, the coincidence signal obtained by comparing the position signal from the detector η and the position setting device, etc. , depending on the number of pulses selected and the pulse transmission speed K, each digital type ffi''1 immediate valve 3.7゜2
2, the speed and pressure rise, The falling characteristics are also f! yj
Therefore, more fine-grained and precise control is performed compared to the control of conventional proportional electromagnetic control valves. Also, each digital 2f! ! The I+ control valves 3, 7, and 22 are controlled by sending pulse signals to the stepping motors 45° and 10.21, respectively, so they are not affected by disturbance factors such as oil temperature, room temperature, and power supply fluctuations. (Even if the molding is repeated, the quality of each molded product remains constant and maintained at the local level.

In addition, 'XO! In the hydraulic circuit shown in the example, a digital flow 1 control valve 3 is used to reduce energy consumption.
Although the above description has been made with a configuration in which the digital pressure control valve 7 is integrally connected to the discharge end of the hydraulic pump 1, the present invention is not limited to this, and for example, as shown in FIG. In the cylinder 5o and its control flJt1'+l valve 51,
A dedicated digital flow control valve 52 is connected to the dedicated digital flow control valve fP52, and a digital pressure control valve 53 is installed between the digital flow control valve 52 and the hydraulic pressure supply source 54 in a manner that is separate from the digital flow control valve 52. As a function, the digital flow control valve 52 may be one that controls only the cylinder 5o, or one that controls two valves that require simultaneous operation, as shown in FIG. Shi! Nonda 55°56 and their f! 7i control 'heart magnetic valve 57, 581C ^, pressure reducing valve 59 with digital type +111-]
A no-load circuit 61 may be arranged between the hydraulic pressure supply source 54 and each pressure reducing valve 59 with the digital type 11i7. Also, as shown in Figure 9, the accumulator 462, pressure switch 63, check valve 64, and no-load circuit 6N are assembled.
It can also be applied to hydraulic circuits to ensure high horse power and reduce power loss. Furthermore, as shown in the alO diagram, the side leg @ 66 of the variable pump 65 includes a throttle switching valve 67, a digital pressure fXn valve 68, and a 1-noleaf valve 69! l
In a pre-use hydraulic circuit 70, or in a multiple pump circuit in which a plurality of hydraulic pumps 71, 72 are fully connected as shown in FIG.
! A digital pressure control valve 73,74 is provided at each end to control the energy Il'! You can cut down on your IL expenses. Furthermore, although the electric motor 9 for control phrase attached to the digital snow control valve shown in each of the above-mentioned practical examples is explained as a stepping motor, it is also possible to use a normal 9-inch motor.
, by installing a detector such as the →-Bomeau shoulder double-pulse encoder and determining the position of the valve opening based on the detection signal of this detector, the set flow f' can be adjusted to Control using a servo motor that obtains the power is also possible.

``Effects of the Invention'' As explained above, the present invention provides a hydraulic circuit (t'C) for fully controlling the mold closing, mold opening, injection process, etc., which is operated by a pulse signal. A digital control valve that controls the pressure is installed in the case where there is a current due to movement.
An electric motor is connected to the hydraulic circuit to control the digital control valve (by changing the number of pulses applied to the bird and the pulse feed rate, the flow rate or pressure of oil flowing through the digital control valve can be controlled during injection molding). It is possible to control both the speed and pressure in each process, such as mold opening/closing speed, injection pressure, and back pressure, as well as the rise and fall characteristics of the speed and pressure. In response to the influence of disturbance elements qI ((, it is possible to improve the repeatability during continuous molding, and
It has an excellent young fruit that can be molded into precise single-fat molded products that cannot be molded using conventional stepwise speed change and variable pressure custom orders.

[Brief explanation of the drawing]

Figures 1 to 6 show all @1 practical examples of the present invention. Figure 1 is a schematic configuration diagram showing the overall configuration, and Figure 2 is a flow violet-pulse number characteristic of a digital flow control valve. Fig. 3 is a characteristic diagram showing the pressure-pulse number characteristics of the digital pressure control valve, Fig. 4 is a block diagram explaining the entire speed control section, and Fig. 5 is a block diagram explaining the pressure control section. Figure, 6th
The figure is an operation chart fully explaining the contents of one cycle of the injection molding process, Figure 7 is a hydraulic circuit diagram showing the entire second embodiment of the present invention, and Figure 8 is a hydraulic circuit diagram showing the third embodiment of the present invention. , Fig. 9 is a hydraulic circuit diagram showing a fourth embodiment of the present invention, Fig. 10 is a hydraulic circuit diagram showing a fifth embodiment of the present invention, and Fig. 11 is a hydraulic circuit diagram showing a sixth embodiment of the present invention. It is a diagram. 3...Digital flow control valve 5...Stepping motor 4 (Company J [A machine)] 7...First digital pressure control valve lO...
...Stepping motor (for control [dynamic CI)] 21.
...Stepping motor 4 (tfI2+ machine for control)
22...Second digital pressure control valve 52...
...Digital flow control valve 53...Digital pressure control valve 59...Digital +111-flat pressure reducing valve 60...Digital flow control valve 68.
...Digital pressure control valve 732...74...
...Digital pressure control valve.

Claims (1)

[Claims] In a control device for an injection molding machine that configures a hydraulic circuit and controls mold closing, mold opening, injection process supply, back pressure, ejector, nozzle forward and backward movement, etc. using hydraulic pressure, the hydraulic circuit is driven by a pulse signal. 1. A control device for an injection molding machine, comprising a digital control valve that controls flow rate or pressure using a control motor.