JPH04123860A - Method and device for controlling degassing device in injection molding machine - Google Patents

Abstract

PURPOSE:To rapidly execute the required treatment against the occurrence of defectivity by detecting an injection molten substance at two points of the cavity or the degassing route of the injection molding machine, calculating the flowing time, thereof comparing it with the set time and judging whether the defective products exist or not. CONSTITUTION:The injection molten material is detected at two different points by 1st and the 2nd injection molten material detecting means 69, 101. Then based on the detected signal of each detecting means 69, 101, by calculating the flow time of the injection molten material with the controlling means 102, comparing the flow time with the set time preliminarily set, it is judged whether the defective products occurs or not.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method and device for controlling a degassing device of an injection molding machine such as a die-gast, and particularly to a method and a control device for controlling a degassing device for an injection molding machine such as a die-gast, and particularly for detecting the flow time of a molten material to be injected and detecting the flow time of a molten material to be injected. This invention relates to a device that determines whether or not a defective product has occurred.

(Prior art) As an injection molding machine, for example, Japanese Patent Application Laid-Open No. 62-21485
There are examples such as those shown in Japanese Patent Application Laid-open No. 9, Japanese Patent Application Laid-Open No. 1983-303672, Japanese Utility Model Application Publication No. 83-25244, and Japanese Patent Application Laid-Open No. 1255176.

This will be explained with reference to FIG.

FIG. 4 is a sectional view showing the configuration of an injection molding machine.
A fixed mold 1 and a movable mold 3 are arranged.

A runner 5 is formed between the fixed mold 1 and the movable mold 3, and above the runner 5 in the figure,
A cavity 9 is formed through the gate 7.

A casting sleeve 11 is inserted into the lower part of the fixed mold 1 in the figure and communicates with the runner 5.

A pouring port 13 is formed on the side surface of the right end of the casting sleeve 11 in the figure, and the molten material to be injected is poured through the pouring port 13.

A plunger 15 is housed within the casting sleeve 11 so as to be slidable in the left and right directions in the figure.

This plunger 15 is connected to an injection cylinder 19 via a plunger rod 17.
By appropriately driving 9, it slides within the casting sleeve 11.

A striker 21 is attached to the end of the injection cylinder 19 on the plunger 15 side, and a vacuum start limit switch 23 and a high speed limit switch 25 are arranged at predetermined positions along the path of movement of the striker 21. ing.

The upper end of the cavity 9 in the drawing is a dividing surface portion 27, and a gas vent passage 29 is formed above the dividing surface portion 27 in the drawing. A vacuum suction device 33 is connected to the gas vent passage 29 via a pipe 31. This vacuum suction device 33 includes an electromagnetic switching valve 35, a tank 37, a vacuum pump 39, and a drive motor 41.

The electromagnetic switching valve 35 has switching positions 35a and 35b, and when switched to the switching position 35a, the gas vent passage 29 and the vacuum suction device 33 are communicated with each other.

An on-off valve 43 is inserted into the gas vent passage 29 . This on-off valve 43 is opened and closed by a valve drive mechanism 45. That is, the on-off valve 43
7 and a shaft 49, and the shaft 49 is connected to a piston 53 that is slidably housed in a cylinder 51.

On the other hand, a compressor 55 is installed, and the compressed air from this compressor 55 is transferred to an electromagnetic switching valve 57, a pipe 5
9.61 into the front chamber 63 or rear chamber 65 of the cylinder 51, respectively. Thereby, the piston 53 is slid to either the left or right in the drawing, and the valve body 47 is moved toward and away from the seat portion 67, thereby opening and closing the valve. The electromagnetic switching valve 57 has switching positions 57a and 57b, and compressed air is supplied to the front chamber 63 or the rear chamber 65 by switching to either position.

Further, a detection rod 69 is installed in the gas vent passage 29.

The detection rod 69 detects the molten material to be injected and sends it to the electromagnetic switching valve 5 through an electric circuit (not shown).
7 and, in turn, the opening and closing of the on-off valve 43.

The operation will be explained based on the above configuration.

First, with the on-off valve 43 open, the molten material to be injected is poured from the pouring port 13. At the same time, the injection cylinder 19 is driven to slide the plunger 15 to the left in the figure.

The sliding of the plunger 15 closes the pouring port 13, and the striker 21 operates the vacuum start limit switch 23. In response to actuation of the start switch 23, the electromagnetic switching valve 35 is switched to the switching position 35a via an electric circuit (not shown). This electromagnetic switching valve 3
5, the gas vent passage 29 and the vacuum suction device 33 are opened.
The gas in the casting sleeve 11, the runner 5, and the cavity 9 is sucked and discharged through the gas vent passage 29 and the piping 31.

When the plunger 15 further slides to the left in the figure, the cavity 9 is filled with the molten material to be injected, and the gas vent passage 2
The molten material to be injected comes into contact with the detection rod 69 . In response to the detection signal from the detector 69, the electromagnetic switching valve 57 is switched to the switching position 57b via an electric circuit (not shown).

By the operation of the electromagnetic switching valve 57, the compressor 55
Compressed air is supplied into the front chamber 63 of the cylinder 51, and the piston 53 retreats to the right in the figure. piston 5
3 retreats to a predetermined position, the valve body 47
When the valve is seated, the valve becomes closed. By closing the on-off valve 43, the gas vent path 29 is shut off, and the evacuation by the vacuum suction device 33 is stopped.

(Problems to be Solved by the Invention) When trying to obtain a product with a desired shape using the above-mentioned conventional configuration, even if vacuum evacuation is performed, if the water temperature is poor, internal defects such as blowholes may occur in the product. This may result in quality deterioration. This is largely due to air being drawn into the molten material to be injected in the injection molding machine.

Various measures have been proposed to monitor such air entrainment. For example, improving the configuration of the gas venting device to ensure better gas venting, or improving the gas venting path 2
The system monitors the pressure inside 9 and issues an alarm if the pressure rises.

However, such measures are still insufficient because they do not directly detect the state of the flow of the molten material to be injected, and it is possible to more accurately grasp the state inside the injection molding machine and detect the occurrence of product defects with high precision. required to do so.

The present invention has been made based on the above points, and its purpose is to reliably grasp the flow state of the molten material to be injected in an injection molding machine and to detect the occurrence of product defects with high accuracy. An object of the present invention is to provide a method and a control device for controlling a gas venting device in an injection molding machine.

(Means for Solving the Problems) In order to achieve the above object, a method for controlling a gas venting device in an injection molding machine according to the present invention is such that when the on-off valve inserted in the gas venting passage is open, The molten material to be injected is injected into the cavity through the injection cylinder, and is extruded by a plunger driven by an injection cylinder.
An injection molding machine is provided, wherein after a predetermined period of time has elapsed after the pouring port is closed by the plunger, a vacuum is drawn through a gas vent passage by a vacuum suction device, and then the vacuum is stopped by closing the opening/closing valve. In the degassing device control method, the flow time of the injected melt is calculated by detecting the injected melt at two arbitrary points in the cavity or the gas vent path, and the flow time and the preset setting time are calculated. The feature is that the comparison is made and it is determined whether the product is defective or not based on the comparison result.

Further, the degassing device control device in the injection molding machine according to the present invention injects the molten material to be injected into the cavity through the pouring spout while opening the on-off valve inserted in the degassing passage. This is extruded by a plunger driven by an injection cylinder, and after a predetermined time after the pouring port is closed by the plunger, a vacuum is drawn through the gas vent passage by a vacuum suction device, and then the on-off valve is closed. In the gas venting device control device for an injection molding machine, the device for controlling a gas venting device of an injection molding machine is configured to stop evacuation by stopping evacuation. , a second injected melt detection means for detecting an injected melt at any second point in the cavity or gas vent path, and from the first injected melt detection means and the second injected melt detection means. The flow time of the injected melt is calculated based on the detection signal of
The present invention is characterized by comprising a control means that compares the flow time with a preset time and determines whether or not a product defect has occurred based on the comparison result.

(Function) The method for controlling the position of the gas venting device in an injection molding machine according to the present invention first detects the injected molten material at two arbitrary points in the cavity or the gas venting path.

Next, the flow time of the molten material to be injected is calculated based on each of these detection signals. The calculated flow time is then compared with a preset time to determine whether or not the product is defective. In other words, by directly detecting the flow state of the molten material to be injected, the possibility of air entrainment is detected with high accuracy, and the occurrence of product defects is not detected.

Further, the degassing device control device for an injection molding machine according to the present invention is for implementing the degassing device control device for the injection molding machine described above, and the first and second injected molten material detecting means are used to detect two different types of molten material. Detect the injected melt at the point. Based on the detection signals of each of the above detection means,
The control means calculates the flow time of the molten material to be injected, and compares the flow time with a preset time to determine whether or not a product defect has occurred.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

Note that the same parts as those of the conventional device are given the same reference numerals, and the explanation thereof will be omitted.

As shown in FIG. 1, the position facing the on-off valve 43 (second
At the point), a detection rod 1 is installed as a second injection melt detection means.
01 is installed. That is, the detection rod 69 serving as a first detection means for the molten material to be injected is arranged at the lower part (first point) in the figure of the gas vent passage 29 to detect the molten material to be injected, and then the detection rod 101 detects the molten material to be injected. Detects the molten material to be injected. Based on the detection signals from both detection rods 69 and 101, the flow time of the molten material to be injected is calculated, and the flow time is compared with a preset time to determine whether or not a product defect has occurred. This is to determine the

First, the detection signal of the detection rod 69 is input to the control circuit 103 and comparison circuit 105 of the control means 102. On the other hand, the detection signal of the detection rod 101 is input to the comparison circuit 105. The comparison circuit 105 calculates the flow time of the molten material to be injected based on the rain detection signal. Then, the flow time and the set time inputted from the setting circuit 107 are compared.

If the calculated flow time exceeds the set time, the comparison circuit 105 outputs a control signal to the controller 109 and also outputs an alarm 5ill to indicate that air is being drawn into the molten material to be injected. Let me know if it's likely. Further, the controller 109 appropriately controls the casting machine based on the control signal.

As the detection rod 69.101, for example, one shown in FIG. 2 is used. The detection rod 69 (or 101) has a cylindrical metal holder 3 for holding the electrode rod 1, and a concave hole 3b is provided on the right side of the holder 3 in the figure, and a concave hole 3b is provided on the left side of the holder 3 in the figure. A recessed hole 3c is provided in the. The recessed hole 3b and the recessed hole 3c are connected by a connecting hole 3a.

A cylindrical glass 2 for electrically insulating the electrode rod 1 and the holder 3 is housed in the recessed hole 3b, and a through hole for passing the electrode rod 1 is provided in the center of the glass 2. A center hole 2a is formed as a central hole 2a, and an expanding inclined surface 2b is formed at the right end in the figure (molten metal detection side end).

The electrode rod 1 extends in the longitudinal direction at the center of the holder 3, and includes a shaft portion 1a and a head portion 1b enlarged at the tip of the shaft portion 1a. The head 1b has an expanding inclined surface IC that engages with the expanding inclined surface 2b of the glass 2, and a sensing portion 1d that contacts the molten metal. The shaft portion 1a has a threaded portion 1e at its rear end (left side in the figure).

The inner diameter of the center hole 2a in the glass 2 is set to be larger than the outer diameter d of the shaft portion of the electrode rod l by a predetermined dimension,
An annular gap 4 is formed between the electrode rod 1 and the glass 2.

The size of this gap 4 is set so that when the electrode rod 1 thermally expands due to a rise in temperature due to contact with molten metal, the expansion force will not affect the glass 2 even if the electrode rod 1 thermally expands. The dimensions are set so as not to contact the inner circumferential surface of the center hole 2a in 2.

The threaded portion 1e is provided with an expanded inclined surface 1c of the head 1b of the electrode rod 1 in close contact with an expanded inclined surface 2b of the glass 2 to close the open end of the gap on the molten metal detection side and allow the molten metal to enter the holder 3. An electrode rod head holder H is attached to prevent the intrusion of the electrode rod. This holder H includes an insulating washer 5 that is in contact with the front end wall 3d of the concave hole 3c of the holder 3, a tightening nut 7 that presses the insulating washer 5 via a spring washer 6, and a rear side of the nut 7. It has a wiring fixing nut 8 which is screwed together with the tightening nut 7 for fixing the wiring 9 connected to the electrode rod 1.

The insulating washer 5 is attached to the shaft portion 1a of the electrode rod 1 and the holder 3.
The spring washer 6 always urges the electrode rod 1 to the left side in the drawing by its elastic force, and even when the electrode rod 1 thermally expands, the glass 2 and the head 1b of the electrode rod 1 are kept in contact with each other. Both expansion inclined surfaces are brought into close contact to prevent molten metal from entering into the holder 3.

In this way, the spring washer 6 covers the fact that the electrode rod 1 expands in the axial direction due to temperature rise and loosens its tightening. If this is done in the same condition, the effect of preventing loosening can be made more reliable.

The detection rods 69 and 101 are connected to the control circuit 103 or the comparison circuit 1 via wiring 9 connected to each electrode rod l.
It is connected to 05. When the molten material to be injected reaches the detection section 1d, it is detected and the control circuit 10
3 or outputs a detection signal to the comparison circuit 105.

Note that the control circuit 103 may be configured by a relay circuit or a switch circuit, or may be an electronic circuit consisting of a flip-flop circuit or a monostable multi-by-break circuit.

The operation will be explained based on the above configuration.

First, with the on-off valve 43 open, the molten material to be injected is poured from the pouring port 13. At the same time, the injection cylinder 19 is driven to slide the plunger 15 to the left in the figure.

The sliding of the plunger 15 closes the pouring port 13, and the striker 21 operates the vacuum start limit switch 23. Thereby, controller 1
09, the electromagnetic switching valve 35 is switched to the switching position 35a. By operating this electromagnetic switching valve 35, the gas vent passage 29 and the vacuum suction device 33 are communicated, and the gas in the casting sleeve 11, runner 5, and cavity 9 is sucked and exhausted through the gas vent passage 29 and the piping 31. be done.

When the plunger 15 further slides to the left in the figure, the cavity 9 is filled with the molten material to be injected, and the gas vent passage 2
Pushed out into 9. Thereby, the molten material to be injected comes into contact with the detection rod 69. Thereby, the electromagnetic switching valve 57 is switched to the switching position 57b via the control circuit 103.

By the operation of the electromagnetic switching valve 57, the compressor 55
Compressed air is supplied into the front chamber 63 of the cylinder 51, and the piston 53 retreats to the right in the figure. As a result, the valve body 47 is seated on the seat portion 67 to be in the valve closed state. By closing the on-off valve 43, the gas vent path 29 is shut off, and the evacuation by the vacuum suction device 33 is stopped.

Further, the signal from the detection rod 69 is also input to the comparison circuit 105. Thereafter, when the gas vent passage 29 is further filled with the molten material to be injected, the molten material to be injected comes into contact with the detection rod 101 . The detection signal of the detection rod 101 is sent to the comparison circuit 10.
5 is input.

The comparison circuit calculates the flow time of the molten material to be injected based on the two input detection signals, and calculates the flow time of the melt to be injected based on the flow time and the setting circuit 107.
Compare with the set time input. If the flow time exceeds the set time, a signal is output to the controller 109 and an alarm 5111 is output.

For example, as shown in FIG.
It is assumed that the on-off valve 43 closes emsec after outputting . Further, the setting time set by the setting circuit 107 is assumed to be 25 m5 e c. Therefore, the detection rod 69
If the detection rod 101 detects the molten material to be injected within 25 m5 ec after the detection rod 101 detects the molten material to be injected, it is determined that the molten material to be injected is flowing normally and there is no entrainment of air.

On the other hand, if the detection rod 101 does not detect the injected molten material within 25 m5 ec after the detection rod 69 detects the injected molten material, the injected molten material is not circulating normally. It is determined that air entrainment has occurred.

It should be noted that the present invention is not limited to the above embodiment,
Various changes and modifications are possible. For example, the two points at which the molten material to be injected is detected are not limited to the illustrated locations, and may be any different locations.

Detection rod 69.101 as first and second ejection detection means
Various configurations other than those shown are possible.

(Effects of the Invention) As detailed above, according to the method and device for controlling a gas venting device in an injection molding machine according to the present invention, the following effects can be achieved.

First, it is possible to easily and reliably detect whether or not a product defect has occurred. This is because the state of the flow of the molten material to be injected is directly detected, and based on this, it is determined whether or not a defective product has occurred. Therefore, necessary measures can be taken quickly even when product defects occur.

Furthermore, since the detection rod 69 for closing the on-off valve is used as the first injected melt detection means, it is only necessary to newly provide a detection rod lot as the second injection melt detection means. The configuration is also extremely simple.

[Brief explanation of the drawing]

Figures 1 to 3 are diagrams showing an embodiment of the present invention. Figure 1 is a diagram showing the configuration of an injection molding machine, Figure 2 is a cross-sectional view of the detection rod, and Figure 3 is a diagram showing the operation. , FIG. 4 is a diagram showing a conventional injection molding machine. DESCRIPTION OF SYMBOLS 1... Fixed mold, 3... Movable mold, 9... Cavity, 13... Pouring spout, 15... Plunger, 19
...Injection cylinder, 29...Gas vent passage, 33...
- Vacuum suction device, 43... Opening/closing valve, 45... Opening/closing valve drive mechanism, 69... Detection rod (first injection detection means),
101... detection rod (second ejection detection means), 102...
...control means. Agent Patent Attorney Ihiro Kitayo (and 2 others) Procedural Amendment December 3, 1991 2゜3゜4゜1990 Patent Application No. 245789 Title of Invention Gas venting device control method and control for injection molding machine Relationship with the device amendment case Patent applicant address: 762 Mezakicho, Fuchu City, Hiroshima Prefecture Name: Ryobi Corporation Representative: Hiroshi Urakami, President and CEO

Claims (2)

[Claims] (1) With the opening/closing valve inserted in the gas vent path open, the molten material to be injected is injected into the cavity through the pouring port, and is pushed out by the plunger driven by the injection cylinder. and after a predetermined period of time has elapsed after the pouring port is closed by the plunger, a vacuum is drawn through a gas vent passage by a vacuum suction device, and then the vacuum is stopped by closing the opening/closing valve. In a method for controlling a gas venting device of a machine, the flow time of the melt to be injected is calculated by detecting the melt to be injected at any two points in the cavity or the gas vent path, and the flow time and the preset time are calculated. A method for controlling a gas venting device for an injection molding machine, characterized in that the presence or absence of a product defect is determined based on the comparison result. (2) With the on-off valve inserted in the gas vent path open, the molten material to be injected is injected into the cavity through the pouring port, and is pushed out by the plunger driven by the injection cylinder. and after a predetermined period of time after the pouring port is closed by the plunger, a vacuum is drawn through a gas vent passage by a vacuum suction device, and then the vacuum is stopped by closing the opening/closing valve. In the degassing device control device, a first injected molten material detection means detects the injected molten material at an arbitrary first point in the cavity or the gas venting path, and an arbitrary second point in the cavity or the gas venting path. a second melt detection means for detecting the melt to be injected; and a flow time of the melt to be injected based on detection signals from the first melt detection means and the second melt detection means. and a control means for calculating the flow time and a preset setting time, and determining whether or not a product defect occurs based on the comparison result. Device control device.