JPH0623504A - Method and device for detecting gas venting condition in die - Google Patents

Abstract

PURPOSE:To obtain stable detecting output and to facilitate the handling of a device. CONSTITUTION:At the time of executing no injection, passages 16, 17 for detecting pressure and the differential pressure detecting means 30 are cut off and also, by always spouting the air to the passages 16, 17 for detecting pressure by air purge means 20, this passages are cleaned. At the time of executing the injection, the air spouting into the passages 16, 17 for detecting pressure is interrupted, and also by communicating the passages 16, 17 for detecting pressure with the differential pressure detecting means 30, the differential pressure between the pressure P1 at the inlet part 14 of a venturi flow passage 13 and the pressure P2 at a stroke part 15, is detected and this flowing is grasped to detect the gas venting condition in the die 73.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for detecting a state of degassing in a mold, and shows a state of degassing in a mold which is an index of a casting state in a die casting machine or a molding state in a plastic injection molding machine. It can be used when detecting.

[0002]

2. Description of the Related Art As a method and an apparatus for detecting a degassing state in a mold during injection, the applicant of the present application has proposed a method using a wind speed sensor (Japanese Patent Publication No. 2-38306).
(See Japanese Patent Publication). In FIG. 7, the in-mold degassing state detection device 90 is arranged on a mold 83 including a moving mold 81 and a fixed mold 82. Between the movable die 81 and the fixed die 82, a gas vent vent 84 communicating with a cavity of a die 83 (not shown) is provided, and this gas vent vent 84 has a zigzag shape in part. The gas discharge port 85 is formed on the side opposite to the cavity.

The device for detecting the state of degassing in the mold 90 is composed of a mold 83
It has a diffuser block 91 arranged above and an air cleaning device 92. The diffuser block 91 includes a first block 91A fixed to a fixed mold 82 and a second block 91A on the left side in FIG. 7 of the first block 91A.
91B and these blocks 91A, 91
B is joined to each other at a joint end surface 93.

A diffuser portion 94 communicating with the gas discharge port 85 is formed at the joint portion of the blocks 91A and 91B.
In the blocks 91A and 91B, secondary flow passages 95 and 96 communicating with the inlet of the diffuser portion 94 are formed, respectively. Among these, in the secondary flow path 95, a wind speed sensor 97 for measuring the wind speed of the secondary flow flowing therein is provided, and this wind speed sensor 97 is used for decreasing the temperature of the platinum thin wire heater due to the cooling action of the air flow. This is a method of detecting the accompanying resistance change with a bridge circuit. The air purifying device 92 is provided to supply clean air with little dust or the like to the secondary flow path 95 and prevent dust or the like from adhering to the platinum thin wire heater of the wind velocity sensor 97 and deteriorating its measurement accuracy. Has been.

In such a conventional example, when the gas in the cavity of the mold 83 is ejected from the gas discharge port 85 through the gas vent vent 84, it is ejected from each of the secondary flow paths 95, 96. Air flows into the diffuser portion 94. Then, by detecting the wind speed of the secondary flow in the secondary flow path 95 at this time by the wind speed sensor 97, the degassing state in the mold 83 is detected.

According to such a conventional example, the wind speed sensor 97
Therefore, it is possible to perform detection with a high response speed, and since the secondary flow passing through the wind speed sensor 97 by the air cleaning device 92 is clean air with little dust and the like, It is possible to prevent a decrease in measurement accuracy.

[0007]

However, in the conventional example using the wind speed sensor 97 as described above, although the response speed can be detected quickly, the output is unstable and the reliability is high. There was a problem of chipping. Further, the air purifier 92 is required to completely clean the air by using a micro filter or the like in order to prevent a decrease in measurement accuracy due to adhesion of dust or the like to the platinum fine wire heater of the wind speed sensor 97. There is a problem in that maintenance is time-consuming because the filter effect is always maintained good.

An object of the present invention is to provide a method and apparatus for detecting a degassing state in a mold that can obtain a stable detection output and can be easily handled.

[0009]

The method for detecting the degassing state in a die according to the present invention is a degassing state in a die when the gas in the die is released from a gas release port through a degassing vent during injection. A detection method, wherein a flow detection means for detecting a flow associated with gas emission from the gas emission port is provided, and the flow detection means and the flow from the gas emission port are communicated with each other by a flow detection passage, When the injection is not performed, the flow detecting passage and the flow detecting means are shut off,
When the flow detection passage is constantly jetted with air to clean it and ejected, the air jetting to the flow detection passage is interrupted, and the flow detection passage and the flow detection means are communicated with each other. It is characterized by detecting a flow.

Further, the apparatus for detecting the degassing state in the die according to the present invention detects the degassing state in the die when the molten material is filled in the die to form a predetermined shape. A state detection device, which detects a flow path provided on an extension line of a gas discharge port for discharging gas in the mold through a gas vent, and a flow accompanying gas discharge from the gas discharge port. The present invention is characterized by including a flow detection unit, a flow detection passage that connects the flow detection unit and the flow path, and an air purge unit that ejects air to clean the flow detection passage.

[0011]

According to the present invention as described above, when the injection is not performed, the flow detecting passage is always blown with air to clean the flow detecting passage, so that the flow detecting means obtains a stable and accurate detection output. Will be able to. Further, since the air purging means of the present invention cleans the flow detecting passage by ejecting high-pressure air, air for preventing adhesion of dust and the like to the platinum thin wire heater of the conventional example using the wind speed sensor described above. It is possible to easily perform maintenance without the need for regular cleaning such as a cleaning device. Further, since the flow detecting passage and the flow detecting means are shut off while the flow detecting passage is being cleaned by the air purging means, it is possible to prevent inconveniences such as breakage of the flow detecting means due to ejection of high pressure air. It becomes possible to achieve the above-mentioned object.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a device 10 for detecting the state of degassing in the mold
Is a mold 73 composed of a moving mold 71 and a fixed mold 72.
It is placed on top. Between the movable mold 71 and the fixed mold 72, a gas vent 75 that communicates with the cavity 74 of the mold 73.
This gas vent vent 75 is formed so that a part thereof is zigzag, and the outlet on the side opposite to the cavity 74 is a gas discharge port 76.

The degassing state detection device 10 in the mold is composed of a mold 73
The venturi member 11 arranged above and the differential pressure detecting means which is a flow detecting means for grasping the state of the flow by detecting the pressure of each part of the flow path in the venturi member 11
30 and the pressure detecting passage 1 which is a flow detecting passage for connecting the differential pressure detecting means 30 and the passage in the venturi member 11 to each other.
6 and 17 and air purge means 20 for cleaning the pressure detecting passages 16 and 17 by jetting air.

The venturi member 11 is composed of a first venturi member 11A fixedly installed in the movable mold 71 and a second venturi member 11B fixedly installed in the fixed mold 72. 11A and 11B are
They are joined to each other at the joining end face 12. Venturi parts
A venturi flow path 13 that communicates with the gas discharge port 76 is formed at the junction of 11A and 11B.

The differential pressure detecting means 30 detects the differential pressure between the pressure P1 at the inlet portion 14 of the venturi passage 13 and the pressure P2 at the throat portion 15 and ejects the venturi passage 13 from the gas discharge port 76.
It is configured to grasp the state of gas flow inside. Venturi channel 13 inlet 14 and throat 15
The differential pressure detecting means 30 and the differential pressure detecting means 30 are communicated with each other via the air purging means 20 by the pressure detecting passages 16 and 17, respectively.

The air purging means 20 includes an air source 21 which is a supply source of air for air purging, a micro filter 22 for cleaning the air supplied from the air source 21, and a pressure adjustment for adjusting the pressure of the air. It has a valve 23, switching valves 24 and 25 for switching between air purge and differential pressure detection, and open / close valves 26 and 27 for opening the air circuit to the atmosphere.

When the injection is not performed, the air purging means 20 switches the switching valves 24 and 25 to the air purging side, respectively, so that the pressure detecting passages 16 and 17 and the air source 21 are in communication with each other so that clean air is constantly supplied. The pressure detection passages 16 and 17 are supplied to the pressure detection passages 16 and 17 to be air-purged. Then, at the time of injection, the switching valves 24 and 25 are switched to the differential pressure detection side, respectively, and the pressure detection passages 16 and 17 and the differential pressure detection means 30 are made to communicate with each other, and the venturi flow from the pressure detection passages 16 and 17, respectively. Pressure P1 at inlet 14 of passage 13 and throat 15
Of the pressure P2 and the pressure difference between them is measured.

The on-off valves 26 and 27 are opened to open to the atmospheric pressure at the time of air purging when the above-mentioned injection is not performed,
Even if high-pressure air for air purging leaks from each switching valve 24, 25, the differential pressure detecting means 30 is not affected. The on-off valves 26 and 27 are adapted to close the differential pressures from the respective pressure detecting passages 16 and 17 to the differential pressure detecting means 30 when the differential pressures at the time of injection are detected. .

In FIG. 2, the switching valves 24 and 25 and the on-off valves 26 and 27 of the air purge means 20 are solenoid valves. Also, the switching valves 24 and 25 are also non-leak valves with a small air leak amount, and the normal air leak amount is 1 to 3 cc.
Although it is about / min, the atmospheric pressure is released by the on-off valves 26 and 27 as described above in order to prevent the differential pressure detection means 30 from being affected by this small amount of air leakage.

On the other hand, the differential pressure detecting means 30 is an ultrafine differential pressure sensor.
31 and its electronic circuit 50, the output of the differential pressure detection means 30 is input to the control device 60 of the die casting machine having a built-in microcomputer and the like.

In FIG. 3, the ultra-fine differential pressure sensor 31 of the differential pressure detecting means 30 includes a diaphragm 32 which is a pressure receiving portion, and cases 33 and 34 which sandwich the diaphragm 32 from both sides. The diaphragm 32 is a so-called silicon wafer formed by slicing a single crystal of silicon into a thin plate. On both side surfaces of the diaphragm 32, thin recessed portions 35, 36 are left with their outer edges.
Are formed. The cases 33 and 34 are glass discs, and pressure receiving ports 37 and 38, through which the pressure P1 of the inlet portion 14 of the Venturi flow path 13 and the pressure P2 of the throat portion 15 are introduced, are opened in the central portions thereof. There is. The pressures P1 and P2 guided to the pressure receiving ports 37 and 38 are transmitted to the recessed portions 35 and 36 closed by the cases 33 and 34, respectively.
In addition, the outer edges of both sides of the diaphragm 32 and each case 3
Bonding surfaces 39, 40 with 3, 34 are made airtight by adhesion.

Metal films 41 and 42 are vapor-deposited on the bottom surfaces of the recessed portions 35 and 36 of the diaphragm 32. The metal films 41 and 42 are deposited.
Are electrically connected to the electrodes 43 and 44 exposed to the outside, respectively. On the other hand, on the case 33, 34 side, metal films 45, 46 are vapor-deposited so as to correspond to the metal films 41, 42 with the recessed portions 35, 36 being separated, and these metal films 45, 46 are respectively exposed to the outside. It is electrically connected to the exposed electrodes 47 and 48. And diaphragm 32
Side metal films 41, 42 and cases 33, 34 side metal films 45, 46
Capacitors having electrostatic capacitances C1 and C2 are formed by the gaps A1 and A2, respectively.

Such an ultra-fine differential pressure sensor 31 is provided at each pressure receiving port.
The diaphragm 32 bends due to the pressure difference between the pressures P1 and P2 applied from 37 and 38, and the clearance gaps A1 and A2 change, which changes the electrostatic capacitances C1 and C2.
The change of C1 and C2 is sent to the electronic circuit 50, and the differential pressure P1-P2 is calculated here.

FIG. 4 shows a detailed structure of the electronic circuit 50 of the differential pressure detecting means 30. The electronic circuit 50 is a known one. In the figure, the electrodes 43 and 44 of the ultra-fine differential pressure sensor 31 described above are used as a common electrode and are connected to the ground 51, and the electrodes 47 and 48 include a primary winding N1 and secondary windings N2 and N3. It is connected so that the output of the oscillator 53 is given via the transformer 52. Therefore, the capacitance C of the ultrafine differential pressure sensor 31
The capacitors C1 and C2 are connected in the opposite directions.
Current flows according to the difference between 1 and C2.

The current flowing according to the difference between the electrostatic capacitances C1 and C2 flows through the diodes 56 and 57, and the average current I ₀ is converted into the output voltage E ₀ by the current / voltage converter 54. , Is sent to the control device 60 of the die casting machine. The current / voltage converter 54 is an operational amplifier.
55 and a resistor R ₀ connected to its feedback circuit, the output voltage E ₀ is given by E ₀ = I ₀ × R ₀ .

The control unit 60 of the die casting machine receives the output voltage E ₀ from the differential pressure detecting means 30, directly the output voltage E as an analog waveform as shown in FIG. 5 by the display means such as a liquid crystal display device (not shown) ₀ Is output or displayed, or the output voltage E ₀ is converted into a flow state quantity such as a wind speed and an air volume by calculation, and is output. Further, these output results are stored in a storage device of a microcomputer incorporated in the control device 60 of the die casting machine and can be output again.

In this embodiment, the degassing state in the mold is detected as follows. First, when the injection is not performed, the switching valves 24, 25 of the air purge means 20.
Is switched to the air purge side, and the pressure detection passage 16 and
Clean 17 by air purge and open / close valve
26 and 27 are opened to open the air circuit to the atmosphere to protect the differential pressure detection means 30 from leakage of high pressure air.

Next, at the time of injection, the switching valves 24 and 25 of the air purge means 20 are switched to the differential pressure detection side and the on-off valve is opened.
26 and 27 are closed, and the pressure difference between the pressure P1 at the inlet portion 14 and the pressure P2 at the throat portion 15 of the gas flow ejected from the gas discharge port 76 and flowing in the venturi flow path 13 is determined by the pressure detecting passages 16, 17 The flow state is detected by the differential pressure detection means 30 via the, and the result is output and displayed by the control device 60 of the die casting machine. Then, by comparing the output result, for example, an analog waveform as shown in FIG. 5, the degassing state in the mold 73 is managed.

According to the present embodiment as described above, when the injection is not performed, the air purging means 20 constantly blows out the pressure detecting passages 16 and 17 to clean the pressure detecting passages. A stable and stable detection output can be obtained.

Further, since the air purging means 20 cleans the pressure detecting passages 16 and 17 by ejecting high pressure air, dust and the like are prevented from adhering to the platinum thin wire heater of the conventional example using the wind speed sensor 97 described above. Air purifiers for response 92
Compared with the above case, the maintenance can be easily performed by prolonging the filter replacement period.

Further, since the pressure detecting passages 16 and 17 and the differential pressure detecting means 30 are shut off by the switching valves 24 and 25 while the pressure detecting passages 16 and 17 are being cleaned by the air purging means 20,
It is possible to prevent the inconvenience that the differential pressure detecting means 30 is damaged due to the ejection of high-pressure air. Further, at this time, since the open / close valves 26 and 27 are opened to open the air circuit to the atmosphere, the differential pressure detecting means 30 can be protected from the leakage of high pressure air of the switching valves 24 and 25, and further. It is possible to prevent the inconvenience of breakage of the differential pressure detection means 30.

Further, the ultrafine differential pressure sensor 31 of the differential pressure detecting means 30.
Is a diaphragm 32 which is a so-called silicon wafer in the pressure receiving portion.
Since this is a stable material and has a simple structure, it is less susceptible to dust and the like and stable detection is possible compared to the case of the conventional platinum thin wire heater type wind speed sensor 97. You can

Since the differential pressure detecting means 30 displaces the diaphragm 32 by the differential pressure and thereby changes the electrostatic capacitances C1 and C2 to obtain the output voltage E ₀ , the wind speed sensor 97 of the platinum thin wire heater system can be used. Compared with the case, stable detection can be performed.

FIG. 6 shows another embodiment of the present invention. In the figure, the degassing state detection device 110 in the mold
Is a mold 73 composed of a moving mold 71 and a fixed mold 72.
It is placed on top. The mold 73 is the same as that of the above-mentioned embodiment, and has a structure for ejecting the gas in the cavity 74 (not shown) from the gas discharge port 76.

The degassing state detection device 110 in the mold is
The venturi member 111 disposed on the 73, the pressure detection means 130 which is a flow detection means for grasping the state of the flow by detecting the pressure of the flow path in the venturi member 111, and the pressure detection means 130. Venturi member 11
The pressure detection passage 115 that is a flow detection passage that communicates with the flow passage in 1 and the pressure detection passage 115 that is formed by ejecting air.
And an air purge means 120 for cleaning the above.

The venturi member 111 includes a first venturi member 111 A fixedly installed on the movable mold 71 and a fixed mold 72.
And a second venturi member 111B fixedly installed in the venturi member 111A, 111B.
Are joined to each other at the joining end surface 112. A Venturi flow path 113 communicating with the gas discharge port 76 is formed at the joint between the Venturi members 111A and 111B. Further, a secondary passage 114 communicating with the inlet of the venturi passage 113 is formed in the venturi member 111B. The secondary flow path 114 and the pressure detecting means 130 are communicated with each other by the pressure detecting passage 115 via the air purging means 120.

The air purging means 120 has substantially the same structure and operation as the air purging means 20 of the above embodiment.
Air source 121, which is the supply source of air for air purging
A micro filter 122 for cleaning the air supplied from the air source 121, and a pressure adjusting valve 12 for adjusting the pressure of the air.
3, a switching valve 124 for switching between air purging and pressure detection, and an opening / closing valve 126 for opening the air circuit to the atmosphere.

In such another embodiment, the degassing state in the mold is detected as follows. First, when the injection is not performed, the switching valve 12 of the air purge means 120.
4 is switched to the air purge side, and pressure detection passage 11 is always
Keep 5 clean by air purge and open / close valve
Open 126 to open the air circuit to the atmosphere,
Protect the 130 from high pressure air leaks.

Next, at the time of injection, the air purge means 120
Switch the switching valve 124 to the pressure detection side and open / close the valve.
126 is closed, and the pressure of the secondary flow in the secondary flow path 114 generated by the ejecting action of the gas ejected from the gas discharge port 76 and flowing in the Venturi flow path 113 is adjusted to
The pressure state is detected by the pressure detection means 130 via the, and the result is output and displayed by the controller 60 of the die casting machine. Then, by comparing the output result, for example, the analog waveform as shown in FIG.

According to such another embodiment, the pressure detecting means 130 can obtain a stable and accurate detection output, or the maintenance of the air purging means 120 can be easily performed by prolonging the filter replacement period. It is possible to obtain substantially the same effect as that of the above-described embodiment.

The present invention is not limited to the above-mentioned embodiment, and the following modifications and the like are also included in the present invention. That is, the flow detection means of each of the above-described embodiments is the differential pressure detection means 30 and the pressure detection means 130, respectively.
However, the state of the flow accompanying the gas ejection from the gas discharge port 76 may be grasped by either such differential pressure detection or single part pressure detection.

Further, the opening position of each pressure detecting passage 16, 17, 115 to each flow passage is not limited to the position in each of the above-mentioned embodiments, and for example, the opening position of each pressure detecting passage 16, 17 is It is not necessary to be the inlet portion 14 and the throat portion 15 of the Venturi flow path 13 exactly, and there is no need for the opening position and opening angle that can determine the absolute value of the wind speed and the air volume, in short, the gas from the gas discharge port 76. It suffices if data that can be used as an index of the flow state associated with the jet is obtained.

Then, by using the data as an index of such a flow state, it is possible to perform the calibration to determine the absolute values of the wind speed and the air volume, and the relative comparison is performed in the form of the data as it is. It is also possible to manage the degassing state in the mold 73.

Further, each pressure detecting passage 1 of each of the above embodiments
The distances, arrangements, shapes, etc. of 6, 17, 115 are arbitrary, and in short, it is sufficient that the venturi flow path 13, the secondary flow path 114 and the differential pressure detection means 30 and the pressure detection means 130 can communicate with each other. However, it is desirable to shorten these distances in order to improve the responsiveness, and by doing so, the accuracy of detection by the differential pressure detection means 30 and the pressure detection means 130 can be increased.

Further, the air purging means 2 of each of the above embodiments
The arrangement of the 0, 120 switching valves 24, 25, 124 and the open / close valves 26, 27, 126, etc. is not limited to the arrangement of each of the above-described embodiments, in short, switching to air purge, opening of the air circuit to the atmosphere, etc. The arrangement may be any arrangement that satisfies each of the above actions.

Then, the switching valves 24, 25, 124 of the above respective embodiments
Is a no-leak valve with a small amount of air leakage (normal air leakage amount is about 1 to 3 cc / min), but it is not limited to this, and a valve with a small amount of air leakage can be selected as appropriate. You may Further, as long as the valve does not completely leak air, the on-off valves 26, 27, 126 for responding to the air leak may be omitted.

Further, the air purging means 2 of each of the above embodiments
Although 0 and 120 are provided with micro filters 22 and 122, respectively, any one can be used as long as it can clean the air supplied from each air source 21 and 121, and the air of each air source 21 and 121 can be sufficiently cleaned. The micro filters 22 and 122 may be omitted as long as they are processed.

In the other embodiment, the secondary flow passage 114 is formed in the venturi member 111B, but it may be formed in the venturi member 111A, or both the venturi members 111A and 111B are formed. It may be formed in.

Further, in each of the above-mentioned embodiments, the in-mold degassing state detecting device 10,110 for detecting the degassing state in the die is used as an index of the casting state in the die casting machine. It can also be applied when detecting the degassing state in the mold as an index of the molding state in a molding machine or the like.

[0050]

As described above, according to the present invention, the flow detecting means for detecting the flow associated with the gas release from the gas outlet is provided, and when the injection is not performed, the air purge means is always provided to the flow detecting means. Since the flow detection passage that conveys the flow status is cleaned by ejecting air, it is possible to obtain highly accurate and stable detection output by the flow detection means, and easy handling including maintenance of the air purge means. Can be done.

[Brief description of drawings]

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

FIG. 2 is a detailed configuration diagram showing details of the air purging means of the embodiment.

FIG. 3 is a detailed configuration diagram showing details of a flow detection unit of the embodiment.

FIG. 4 is a detailed configuration diagram showing another detail of the flow detection unit of the embodiment.

FIG. 5 is an analog waveform diagram showing an output result of the above-mentioned embodiment.

FIG. 6 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing a conventional example.

[Explanation of symbols]

 10,110 Degassing state detection device in mold 20,120 Air purge means 16,17,115 Pressure detection passage which is flow detection passage 30 Differential pressure detection means which is flow detection means 60 Die casting machine control device 73 Mold 76 Gas release port 75 Degassing vent 130 Pressure detection means that is flow detection means

Claims (2)

[Claims] 1. A method for detecting a degassing state in a mold at the time of discharging gas in the mold from a gas discharge port through a gas discharge vent at the time of injection, the flow accompanying gas discharge from the gas discharge port. A flow detecting means for detecting the flow detecting means, and the flow detecting means and the flow from the gas discharge port are communicated with each other through a flow detecting passage, and when the injection is not performed, the flow detecting passage and the flow detecting means are connected to each other. The flow detection passage is shut off, air is constantly jetted to clean the air, and when jetting is performed, air jetting to the flow detection passage is interrupted, and the flow detection passage and the flow detection means are connected to each other. A method for detecting a degassing state in a mold, characterized in that the flow is detected by communicating with each other. 2. An in-mold degassing state detection device for detecting a degassing state in a mold when a molten material is filled in the mold to form a predetermined shape. A flow path provided on an extension of the gas discharge port for discharging the gas through the gas vent, a flow detection means for detecting a flow accompanying the gas discharge from the gas discharge port, the flow detection means and the flow path. An apparatus for detecting a degassing state in a mold, comprising: a flow detection passage communicating with the flow detection passage; and air purge means for ejecting air to clean the flow detection passage.