JPH0794132B2 - Injection control method and injection control device for press molding machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection control method and an injection control device for a press molding machine.

[0002]

2. Description of the Related Art As a conventional injection control device for a press molding machine, for example, when a mold having a plurality of injection gates that can be opened and closed by valves is used, the opening / closing timing of the injection gates is controlled by a signal from a timer. There is something to control. The opening / closing timing of each injection gate is set in advance by a timer, and each injection gate is opened or closed at the time set by the timer. At this time, the timer is set so that any one of the plurality of injection gates is always opened.

[0003]

However, in the injection control method and apparatus of the above-mentioned conventional press molding machine, the opening / closing timing of each injection gate is controlled by the timer, so that variations in the timer, malfunction, setting error, etc. If so, all the injection gates may be temporarily closed during the injection process. In this case, abnormal injection pressure may act on each component such as the valve of each injection gate and damage them. The present invention is for solving such a problem.

[0004]

The present invention solves the above problems by controlling the injection of molten resin from an injection device depending on the position of a valve. That is, the injection control method of the press molding machine of the present invention is such that the molten resin is injected from the injection device through the plurality of openable / closable injection gates into the cavity of the mold in the half-open state, or the mold is clamped during the injection. This is intended for molding, and detects the open / closed state of each injection gate during injection, and when all injection gates are closed at the same time, stops the injection of molten resin from the injection device. It is characterized by Further, the injection control device of the press molding machine of the present invention, the molten resin from the injection device capable of injecting the molten resin by the axial movement of the screw,
It is intended for those who perform molding after injecting into the cavity of a half-opened mold through an injection gate that can be opened and closed by a valve driven by a drive cylinder, or by clamping the mold during injection. It has a closed state detection device capable of detecting that the gate is in a closed state, and a controller to which a signal from the closed state detection device is input, and the controller has all signals from the closed state detection device. Is configured to output a signal for stopping the injection of the injection device when indicates the closed state of the injection gate. The closed state detection device can be configured by a limit switch that detects the movement of the valve, and can also use an electric signal that commands the operation of the valve.

[0005]

Operation: The injection can be stopped by detecting that the valve is in the closed position by the closed state detection device, and if it is detected that all the injection gates are in the closed state at the same time, it is judged as abnormal. .

[0006]

EXAMPLE FIG. 1 shows an example of the present invention. The mold 10 is composed of a lower mold 12 and an upper mold 14. Lower mold 1
Two injection gates 16 and 18 are provided in 2. A valve 20 is provided at each of the injection gates 16 and 18.
And 22 are provided. Valves 20 and 22 have
Drive cylinders 24 and 26 capable of driving these are respectively provided. As the valves 20 and 22 are axially driven by the drive cylinders 24 and 26,
The injection gates 16 and 18 are opened and closed. An injection device 32 for injecting the molten resin into the cavities 28 and 30 is connected to the lower mold 12. A screw 34 is provided in the injection device 32, and the molten resin is injected into the lower mold 12 by moving the screw 34 in the axial direction. Molten resin is injected into the cavity 28 from the injection gate 16 and into the cavity 30 from the injection gate 18. On the side surfaces of the drive cylinders 36 and 38, open state detection limit switches 40 and 42 are attached to the positions where the valves 20 and 22 are most retracted, and closed states are detected when the valves 20 and 22 are most advanced. Limit switches 44 and 46 (closed state detection device) are attached, respectively. The open state detection limit switches 40 and 42 are turned on when the valves 20 and 22 are most retracted in the drive cylinders 36 and 38, that is, when the injection gates 16 and 18 are opened. The closed state detection limit switches 44 and 46 are turned on when the valves 20 and 22 are moved most forward in the drive cylinders 36 and 28, that is, when the injection gates 16 and 18 are closed. Drive cylinders 36 and 38
Electromagnetic valves 48 and 50 are connected to the forward and backward oil chambers, respectively. The solenoid valves 48 and 50 are connected to a hydraulic pressure source 52 and can be switched so as to supply or discharge the hydraulic pressure from the hydraulic pressure source 52 to or from the oil chambers of the drive cylinders 36 and 38. A controller 54 is provided which can control the switching operation of the solenoid valves 48 and 50. The controller 54 includes an open state detection limit switch 4
The signals from 0 and 42 and the closed state detection limit switches 44 and 46 are input. The controller 54 is the injection device 3
It is possible to output a signal to the second control device 33 to permit or stop the injection operation of the signal.

FIG. 2 shows a ladder diagram of the present invention. The control is performed by the controller 54 as shown in this figure. That is, when the open state detection limit switch 40 is on and the closed state detection limit switch 44 is off, or when the open state detection limit switch 42 is on and the closed state detection limit switch 44 is off, the injection valve 20 It is determined that at least one of No. 2 and No. 22 is in the open state, and an injection permission signal is output to the control device 33 of the injection device 32. Also,
An injection permission signal is output when at least one of the solenoid valves 48 and 50 is on (a state in which hydraulic pressure is supplied to the retreating side oil chamber). Conversely, when the injection permission signal is not output, the injection stop signal is set to be output to the control device 32.

Next, the operation of this embodiment will be described.
The mold 10 is brought into a half-opened state as shown, and the screw 34 is moved in the axial direction (left direction in the drawing) to start the injection of the molten resin from the injection device 32 into the lower mold 12. At this time, when the solenoid valves 48 and 50 are both turned on and the valves 20 and 22 are both most retracted, the injection gate 16
Both and 18 are open. As a result, both the open state detection limit switches 40 and 42 are turned on, and the closed state detection limit switches 44 and 46 are both turned off. Therefore, the injection gates 16 and 18 are judged to be normal. As a result, an injection permission signal is output to the control device 33, and the injection device 32 causes the lower die 12 to
Molten resin is injected into the inside. When the solenoid valve 48 is turned on and the solenoid valve 50 is turned off so that the valve 20 is most retracted and the valve 22 is most advanced, the injection gate 16 is open and the injection gate 18 is closed. It has become. As a result, the open state detection limit switch 40 is turned on and the closed state detection limit switch 46 is turned on. In this case as well, it is determined to be normal, the injection permission signal is output to the control device 33, and the molten resin is injected from the injection device 32 into the lower mold 12. With the injection gate 16 closed,
Similarly, when the injection gate 18 is in the open state, it is determined to be normal. Solenoid valves 48 and 50 are both off and valve 2
When 0 and 22 are both most advanced, both injection gates 16 and 18 are closed. This turns off both open state detection limit switches 40 and 42, and close state detection limit switches 44 and 46.
Are both turned on. Therefore, the injection gates 16 and 1
The state of 8 is judged to be abnormal. As a result, an injection stop signal is output to the control device 33, and the injection of the molten resin from the injection device 32 to the lower mold 12 is stopped. In this embodiment, the signals of all limit switches and the solenoid valve actuation signals are used. However, only the signals of the closed state detection limit switches 44 and 46 or only the solenoid valve actuation signals are used. You can also do it.

[0009]

According to the present invention, when it is detected that the valves are in the closed position and it is detected that all the injection gates are in the closed state at the same time, the injection can be stopped as an abnormality. it can. Thereby, even if there is a setting mistake in the opening / closing timing of the injection gate, the abnormal injection pressure does not act on the parts such as the valve of each injection gate, and therefore damage can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is an implementation ladder diagram of the present invention.

[Explanation of symbols]

10 Mold 16, 18 Injection gate 20, 22 Valve 24, 26 Drive cylinder 28, 30 Cavity 32 Injection device 34 Screw 44, 46 Closed state detection limit switch (closed state detection device) 48, 50 Solenoid valve 54 Controller

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29C 45/82 7365-4F

Claims (4)

[Claims] 1. An injection of a press molding machine for performing molding after injecting a molten resin from an injection device through a plurality of openable / closable injection gates into a cavity of a half-open mold, or by clamping the mold during injection. In the control method, the open / close state of each injection gate is detected during injection, and when all the injection gates are closed at the same time, the injection of the molten resin from the injection device is stopped. Machine injection control method. 2. A valve (20, 22) driven by a drive cylinder (24, 26) to open and close the molten resin from an injection device (32) capable of injecting the molten resin by axial movement of a screw (34). Possible injection gate (1
6, 18) through and into the cavity (28, 30) of the semi-open mold (10) after or during injection.
In the injection control device of the press molding machine that clamps (0) and molds, the closed state detection device (44, 46) capable of detecting that the injection gate (16, 18) is in the closed state, and the closed state detection. Controller (54) to which signals from the devices (44, 46) are input
And the controller (54) controls that all signals from the closed state detector (4, 46) are injected by the injection gate (16,
An injection control device for a press molding machine, which is configured to output a signal for stopping the injection of the injection device (32) when the closed state of 18) is indicated. 3. The closed state detection device comprises an injection gate (16,
The injection control device for a press molding machine according to claim 2, wherein the closed state detection limit switch (44, 46) is actuated when 18) is in a closed state. 4. The closed state detecting device comprises valves (20, 2).
The injection control device for a press molding machine according to claim 2, which is a controller (54) that outputs a signal for driving 2).