JPH04123857A - Method for controlling movement of gas vent device in die - Google Patents

Abstract

PURPOSE:To prevent intrusion of molten metal into a valve at the time of casting in low speed and also intrusion of molten metal caused by remained casting flash by driving a gas vent valve arranged in gas vent passage to closing at the same time of starting the low speed injection and driving the valve to opening with a casting flash removal signal at the time of opening the die. CONSTITUTION:The die gas vent device of an injection forming machine 1 is controlled by arranging a process selecting the low speed casting and the high speed casting with a casting machine control circuit A, a process for outputting the low velocity injection signal from the casting machine control circuit A to the control circuit B, a process for outputting injection starting signal from the casting machine control circuit A to the control circuit B, a process for forcedly close the gas vent valve by outputting closing signal of the gas vent valve 9 from the control circuit B with the low velocity injection signal and the injection starting signal and a process to open the gas vent valve 9 with casting flash removal signal from the casting machine control circuit A.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for controlling the operation of a degassing device in a molding machine such as a die casting machine, and more specifically,
The present invention relates to a method for controlling the drive of a gas vent valve used in a gas venting device in an injection molding machine.

[Prior Art] In an injection molding machine such as a die-casting machine, it is necessary to remove gas from the cavity during high-speed injection in order to prevent gas from being drawn into the product and to prevent the formation of cavities. The degassing device for this purpose is provided with a degassing passage communicating from the inside of the mold cavity to the outside of the mold, and further provided with a degassing valve that can be opened and closed freely in the degassing passage. The degassing passage is connected to a suction means such as a vacuum pump or is opened to the outside air in order to efficiently degas the gas.

The gas vent valve is used to prevent the molten metal from flowing into suction means such as a vacuum pump located downstream of the valve, or to prevent the molten metal from blowing out of the mold due to inertia caused by injection. It remains open until it reaches a certain position just before the gas vent in the gas vent passage, and then it needs to close quickly.

However, during high-speed casting, if this valve-closing operation occurs too quickly, gas in the cavity will not be sufficiently vented, and gas entrainment in the product will result in the formation of cavities.

Therefore, during high-speed injection, it is necessary to control the opening/closing operation of the gas vent valve extremely accurately and promptly at the timing described above.

On the other hand, in the die casting method, casting is usually performed at a low speed until the mold temperature reaches a predetermined temperature, and then at a high speed after the mold temperature reaches the predetermined temperature.

Further, when casting is interrupted due to some abnormality and restarted, casting is similarly performed at a low speed.

There is no need for degassing during low-speed injection in such cases. For this reason, during low-speed injection, if the gas vent valve is opened and closed at the same time as the injection of molten metal starts, the molten metal can be shut off by the gas vent valve extremely reliably.

In addition, regardless of whether high-speed casting or low-speed casting is selected, when the mold is opened, it is necessary to open the gas vent valve in order to remove cast waste adhering to the periphery of the gas vent valve.

Conventional techniques for controlling the opening/closing operation of the gas vent valve as described above include Japanese Patent Application Laid-Open No. 34-5652 and Japanese Patent Application Laid-Open No.
-49852, JP-A-60-11591, JP-A-8
There were some disclosed in No. 0-29583 and the like.

[Problem to be solved by the invention] However, JP-A-64-! The control mechanism disclosed in No. 56152 is a mechanism in which an injection rod strikes a limit switch, and the signal generated there causes the valve to close. Therefore, even in the case of low-speed injection, if the limit switch is incorrectly set, when the molten metal reaches the gas vent valve, the valve closing operation is not completed, and there is a risk that the molten metal will enter the valve.

Further, in this mechanism, since the injection rod strikes the limit switch, there is a problem in that the limit switch is damaged and the switch no longer sends a signal.

JP-A-60-49852 outputs a valve closing command according to set injection conditions (mold temperature), and JP-A-60-49852 outputs a valve closing command according to set injection conditions (mold temperature).
)-11591 is the set injection speed (high speed injection range)
It outputs a valve closing command in response to the However, with either control mechanism, it takes time to issue the closing command, and the valve closing operation is not completed by the time the molten metal reaches the gas vent valve.Especially when vacuuming, the molten metal scatters violently, and the inside of the valve is There was a problem with molten metal infiltrating.

Furthermore, in JP-A No. 60-29583, a valve closing signal is output from the solenoid operation command circuit (switch switch) before the start of injection, but since the valve closing command is still being output, the switch does not switch. There is a problem in that the valve cannot be opened unless the valve is opened, and it is difficult to remove cast residue around the valve when the mold is opened.

In view of the above-mentioned problems, the present invention is configured to forcibly (electrically) close the valve almost simultaneously with the start of injection during low-speed injection, and further to open the valve with a casting removal signal when the mold is opened.
Operation control of a mold degassing device that reliably prevents molten metal from entering the valve, and in addition, opens the degassing valve when the mold is opened and easily removes cast waste adhering to the area around the degassing valve. The purpose is to provide a method.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a degassing valve at the opening of a degassing passage led from the cavity, and controls the opening and closing operation of the degassing valve by a casting machine. A method for controlling the operation of a mold degassing device for an injection molding machine, which is controlled by a control circuit connected to a control circuit, including the step of selectively selecting low-speed casting and high-speed casting by the casting machine control circuit. , a step of outputting a low speed injection signal from the casting machine control circuit to the control circuit when selecting the low speed casting, and a step of outputting an injection start signal from the casting machine control circuit to the control circuit when starting injection. outputting a gas vent valve closing signal from the control circuit using the low speed injection signal and the injection start signal to forcibly close the gas vent valve;
Provided is a method for controlling the operation of a mold degassing device, comprising the step of opening the degassing valve in response to the casting removal signal from the casting machine control circuit when the mold is opened after completion of low-speed casting. This is what I am trying to do.

[Operation] As described above, according to the present invention, when low-speed casting is selected, the low-speed casting signal issued from the casting machine control circuit when low-speed casting is selected and the injection signal issued from the casting machine control circuit at the start of injection. The start signal causes the gas vent valve to close, and when the mold is opened after low-speed casting, the cast-off removal signal from the casting machine control circuit causes the scum vent valve to open.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an injection molding machine 1 according to the present invention. The injection molding machine 1 consists of a fixed mold 2 and a movable mold 3.

A cavity is formed between both molds 2.3. Further, a sleeve 14 for injecting molten metal into the cavity is attached to the lower part of the fixed mold 2. Furthermore, inside the sleeve 14 is a pouring port 14a for pouring the molten metal.
have.

A plunger 16 is provided slidably within the sleeve 14 in its axial direction. An operating cylinder 15 is connected to the plunger 16 via a plunger shaft lea.

A runner 13 is provided between the cavity 5 and the sleeve 14 to introduce the molten metal into the cavity 5, and above the cavity 5 is a gas vent passage for leading the gas in the cavity 5 out of the mold 1 during injection of the molten metal. 6 is provided. Further, the gas venting path 6 includes a discharge path 11 whose one end is open to the outside of the mold and the other end is connected to the gas venting path 6.
or are connected.

The discharge passage 11 is provided with a gas vent valve 9 that can be opened and closed. The gas vent valve 9 includes a valve member 9a, a piston 9b,
It is composed of a valve shaft 9c and a guide portion 9d. A valve member 9a is connected to one end of the valve shaft 9c, and a guide portion 9d is connected to the other end via a piston 9b. The valve member 9a is the piston 9
It is movable in the axial direction of the valve shaft 9C by movement within the valve drive cylinder 25 of b, and when the valve member 9a contacts the pedestal portion 12 in a valve closing operation, the exhaust passage 11 is closed and the valve is moved into the cavity 5. It is configured to prevent the filled molten metal from entering in the direction of the exhaust path 11.

The piston 9b is slidably disposed within the valve drive cylinder 25. The valve drive cylinder 25 is formed by the piston 9 into a front chamber 25a, an intermediate chamber 25b, and a rear chamber 25c. The movement of the piston 9 is performed by taking air in and out of the front chamber 25a and the intermediate chamber 25b.

A vacuum suction device is connected to the discharge path 11. This vacuum suction device is composed of a solenoid valve 21, a vacuum pump 20, piping connecting these, and the like. When injecting molten metal, this device operates the vacuum pump 20 by a signal from the control circuit.
and the cavity 5 via the discharge passage 11 and the gas vent passage 6.
It plays the role of forcibly discharging the gas inside the mold to the outside of the mold and preventing gas from getting into the die casting/product.

Furthermore, a molten metal detection sensor 10 is disposed in the gas vent passage 6 to detect the injected molten metal. The sensing sensor 10 has an electrode rod that protrudes into the gas vent G and electrically senses the presence of the molten metal by coming into contact with the conductive molten metal.

Next, the drive mechanism of the gas vent valve 9 will be described in detail.

The drive mechanism includes a control circuit B comprising a flip-flop circuit or the like that generates a valve operating signal based on a sensing signal from the molten metal detection sensor 10 and a signal from the casting machine control circuit A.
, and first and second solenoid valves 61 and 62 that operate in response to a valve operation signal from the control circuit B; an air-operated valve 63 that is operated by air pressure from the solenoid valves and operates the gas vent valve; It consists of a compressor 60 and piping connecting these.

The first and second solenoid valves 61, 62 have the same structure, and switch the air-operated valve 63 in opposite directions by switching a small volume of compressed air.

Further, the first solenoid valve 61 has an input port IP, an output port IP2, an open boat IP8 that is open to the outside air, and a solenoid 61S1 and a return spring 61P. A valve closing signal issued from the control circuit B is input to this solenoid 131s.

On the other hand, the second solenoid valve 62 includes an input port 2P, an output port 2P2, an open port 2P3 open to the outside air, and a solenoid e2. s, f''iJ return spring 62P. A valve opening signal issued from the control circuit B is input to this solenoid 62S.

Return springs 61P and 62P are solenoid EtlS
, E12S is demagnetized, each solenoid valve 61, 62 is returned to its original position.

The air operated valve 63 is input port 3P, output port 3
P2.3P5, open port 3P4.3P5, and first and second pilot members 63a, (33b) for operating the valve are provided at both ends of the valve.

The first and second solenoid valves 61 and 62 and the air operated valve 63
A compressor 60 is connected to supply compressed air. That is, the compressor 60
G to the input port IP of the first electromagnetic valve 61, a pipe 67 to the input port 2P2 of the second electromagnetic valve 62, and a pipe 68 to the input port 3P1 of the air-operated valve 63, respectively.

Further, the output port IP2 of the first solenoid valve 61 is connected to the piping 7.
The output port 2P2 of the second electromagnetic valve 62 is connected to the second pilot member 63b of the air-operated valve 63 by a pipe 72. As a result, the air-operated valve 63 is operated by compressed air from the compressor 60 via the first and second electromagnetic valves 61 and 62.

Furthermore, the output port h3P3 of the air-operated valve 63 is connected to the pipe 6.
9 to the front chamber 25a of the valve driving cylinder 25, and the output port 3P2 is connected to the intermediate chamber 25b2 of the valve cylinder 25 via a pipe 70. As a result, the piston 9b provided in the valve cylinder 25 to operate the gas vent valve 9 is moved to the air-operated valve 63.
The compressed air supplied from the compressor 60 through the valve cylinder slides back and forth in the axial direction, and accordingly, the valve member θa connected to the piston 9b can open and close the discharge passage 11. That will happen.

A pressure control valve 64 is provided in the piping 70, and the pressure adjustment of this pressure control valve 64 is further indicated by a meter 65. The pressure control valve 64 is connected to the intermediate chamber 25b of the valve drive cylinder 25 from the compressor 60 via the air-operated valve 63.
This prevents the gas vent valve 9 from closing prematurely.

Next, the configuration of control circuit B will be explained in detail according to FIG. Control circuit B has a flip-flop circuit 34.

The D terminal of the flip-flop circuit 34 is connected to the casting machine control circuit A, and an injection start signal issued from the casting machine control circuit A at the time of injection start is input. That is, the flip-flop circuit 34 enters a standby state when this injection start signal is input from the casting machine control circuit A.

As shown in FIG.
An OR circuit 31a is connected to the P terminal. A molten metal detection sensor IO is connected to one terminal of the OR circuit 31a via a filter circuit 32, and an AN is connected to the other terminal.
A D circuit 31b is connected.

Further, one terminal of the AND circuit 31b is connected to a delay circuit 31c.
The casting machine control circuit A is connected to the casting machine control circuit A so that an injection start signal is inputted thereto. The other terminal is connected to the casting machine control circuit A so that a low speed casting signal (HIGH) or a high speed casting signal (LOW) is input.

The OR circuit 3-4a is connected to the CL terminal of the flip-flop circuit 34 via a timer 33.

When the output signal from the OR circuit 31a is input, this timer 33 outputs a reset signal d for resetting the flip-flop circuit 34 to the CL terminal of the flip-flop circuit after a predetermined time (short time) has elapsed.

Next, the operation of the degassing device for an injection molding machine according to the present invention will be explained.

First, it is selected whether to perform low-speed casting or high-speed casting. At this time, if low speed casting is selected, the low speed casting signal (HI
GH) is generated from the casting machine control circuit A and input to one terminal of the AND circuit 31b. Note that this low-speed casting signal is always output during low-speed casting.

Next, the molten metal is injected into the sleeve 14 from the sprue 14a and injection by the plunger 16 is started, and at the same time, an injection start signal is issued from the casting machine control circuit A. This injection start signal is input to the D terminal of the flip-flop circuit 34. As a result, the flip-flop circuit 34 enters a standby state. This injection start signal is input to the delay circuit 31c in the control circuit B, and shortly after the flip-flop circuit 34 enters the standby state, the AND
The signal is also input to the circuit 31b, both input terminals of the AND circuit 31b are in a HIGH state, and a signal (HIGH) is output from the AND circuit 31b.

The signal from this AND circuit 31b is input to the OR circuit 31a, and this signal causes the signal a (HI
GH) is output to the CP terminal of the flip-flop circuit 34.

In response to the signal a (HIGH) from this OR circuit, a closing signal for the gas vent valve 9 is output from the Q terminal of the flip-flop circuit to the solenoid f31s of the first electromagnetic valve 61, and the electromagnetic valve 61 is switched. As a result of this switching, the air-operated valve 63 is switched as described above, and the gas vent valve 9 is forcibly closed by a large volume of compressed air from the compressor 60. Subsequently, the plunger 1G is advanced, and the molten metal is degassed. The gas vent valve 9 of the gas vent device rises in the vent passage 6 and contacts the molten metal detection sensor lO, and even if the molten metal detection signal is input to the OR circuit 31a and the signal a is output, the valve closing operation is completed. maintains the valve closed.

When the casting operation is completed and the mold is opened, a casting machine control circuit A issues a casting removal signal to the control circuit B. In response to this casting removal signal, a valve opening signal is output from the control circuit B to the solenoid 62S of the second solenoid valve 62, and the solenoid valve 62
is switched. As described above, this switching causes the air-operated valve 63 to switch, and a large amount of compressed air from the compressor 60 is supplied to the intermediate chamber 25b of the drive cylinder 25. As a result, the valve member 9a of the gas vent valve 9 is separated from the base 12. Therefore, it is easy to remove cast-off material around the valve member 9a. At this time, air is blown from an air source (not shown) around the degassing valve 9, or while giving a mechanical shock to the as-cast material through continuous opening and closing of the degassing valve 9. It may also be configured to remove it.

On the other hand, when high-speed casting is selected, the casting machine control circuit A issues a high-speed casting signal (LOW) to the control circuit B. The AND circuit 31b receives a low-speed injection signal (H
IGH) is not input and the high-speed casting signal (LOW) is always input, so the injection start signal is delayed by the delay circuit 31c.
Even if the signal a is input to the AND circuit 31b through the AND circuit 31b, the signal a is not output from the AND circuit 31b through the OR circuit 31a during high-speed casting.

Here, the flip-flop circuit 34 is in a standby state by an injection start signal issued from the casting machine control circuit at the time of injection start.

As the molten metal is injected by the plunger 1G, the molten metal rises in the cavity 5 and the gas vent path B, and the molten metal detection sensor 1
0, and a molten metal sensing signal is input to the OR circuit 31a in the control circuit B. With this input signal, the OR
The circuit 31a outputs a signal a (HIGH) to the CP terminal of the flip-flop circuit 34. As a result, a closing signal for the gas vent valve 9 is output from the Q terminal of the flip-flop circuit 34 to the solenoid f31s of the first electromagnetic valve 61, and the closing operation of the gas vent valve 9 is started.

The following closing operation of the gas vent valve 9 and opening operation when the mold is opened are the same as those during low-speed casting.

Although the control method according to one embodiment of the present invention has been described above, the present invention is not limited to this.
It is also possible to implement the present invention in injection molding machines having other configurations.

"Effects" As described above, the present invention enables the gas vent valve provided in the gas vent passage to be forced (
The valve is closed electrically, and furthermore, when the mold is opened, the cast part removal signal is used to control the valve to open.

Therefore, even during low-speed casting, the degassing valve can be closed very reliably, and since the valve is opened when the mold is opened, it is possible to easily remove casting debris and the like that have adhered to the vicinity of the valve.

Therefore, even during low-speed casting, it is possible to reliably prevent molten metal from entering the valve, and also to easily remove casting debris adhering to the area around the gas vent valve, thereby reliably preventing molten metal from entering due to residual mold.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of an injection molding machine used in the operation control method of a mold degassing device according to an embodiment of the present invention, and FIG. 2 is a vicinity of the flip-flop circuit in the control circuit B of FIG. 1. FIG. 2 is an explanatory diagram showing the configuration of. In the figure, 1. e. A. B. Mold, 5. Cavity gas vent path, 9. Gas vent valve, ・Flip-flop circuit casting machine control circuit, control circuit not shown.

Claims (1)

[Claims] A gas vent valve is provided at the opening of a gas vent path led from the cavity, and the opening/closing operation of the gas vent valve is controlled by a control circuit connected to a casting machine control circuit. A method for controlling the operation of a mold degassing device for an injection molding machine, comprising: selectively selecting low-speed casting and high-speed casting by the casting machine control circuit; and when selecting the low-speed casting, the casting machine control circuit a step of outputting a low-speed injection signal from the casting machine control circuit to the control circuit; a step of outputting an injection start signal from the casting machine control circuit to the control circuit at the time of injection start; A process of forcibly closing the gas vent valve by outputting a closing signal of the gas vent valve from the casting machine, and a step of forcibly closing the gas vent valve by outputting a closing signal of the gas vent valve from the casting machine control circuit, and a step of forcibly closing the gas vent valve by outputting a closing signal of the gas vent valve from the casting machine control circuit. 1. A method for controlling the operation of a mold degassing device, comprising the step of opening a vent valve.