JPH03189060A - Monitoring instrument for gas venting condition in die casting machine - Google Patents

Abstract

PURPOSE:To surely supervise gas venting condition with high accuracy by dividing flow velocity curve for gas discharged from cavity in a die at the high velocity switching point of injection velocity and comparing the sum of gas velocity curve areas at low velocity part and high velocity part with the set value. CONSTITUTION:Molten metal 15 injected from an injection device 8 is filled up into the cavity 3 in the dies 1, 2. In the above die casting machine, the flow velocity for gas discharged from the cavity 3 through the gas venting flow passage 5 according to filling-up of the molten metal 15, is detected with a blast velocity sensor 21 in a diffuser block 17. This detected value is outputted to a control unit 24 through an A/D converter 23 to obtain the gas flow velocity curve. Further, the injection velocity of molten metal 15 is detected with a magnetic sensor 16 and outputted to the control unit 24 to obtain the high velocity switching point. The areas before and after high velocity switching point in the gas flow velocity curve are obtd. with this control unit 24, and each correcting factor is multiplied to those and the obtd. these values are added. In the case the obtd. sum exceeds the preset permissible range in a setter 30, the alarming signal is outputted to the alarming device 32, etc.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a degassing state monitoring device for a die-casting machine, and is used to monitor whether the degassing state in a mold cavity during an injection process is appropriate. It is suitably used for carrying out.

[Conventional technology]

2. Description of the Related Art Conventionally, die casting machines have taken measures to release gas within a mold cavity when injecting molten metal into a mold. This is because the gas present in the mold cavity causes insufficient pressure to act on the molten metal, resulting in a large number of defective products.

Therefore, we need to understand the gas release state inside the mold cavity.
Due to the need to maintain this with high precision, monitor devices for monitoring the degassing state have been developed.

[Problem to be solved by the invention]

However, the conventional degassing state monitoring device of a die-casting machine has a maximum output value (H
), which determines whether the degassing state is normal or abnormal depending on whether or not it exceeds a preset allowable range, has the following drawbacks.

That is, the maximum value is not necessarily obtained stably, and in reality, the maximum value is often detected with variations from casting cycle to casting cycle.

Therefore, even when the casting condition is a normal degassing state, the maximum value may sometimes exceed the allowable range.

In such a case, a predetermined alarm is generated indicating that an abnormality or the like has occurred in the gas vent flow path, and unnecessary maintenance, inspection work, etc. are forced to be performed. In order to avoid such work, it is conceivable to set the above-mentioned tolerance range widely, but in this case, it is inevitable that abnormal states are also judged as normal, which poses a problem in terms of accuracy.

Therefore, the present invention was made by focusing on the fact that the problem with conventional devices is that the maximum value of the gas flow velocity detection value compared with the allowable range cannot be adopted as a stable value.
The purpose is to provide a device for monitoring the degassing state of a die-casting machine that can monitor the degassing state with high accuracy by making the value to be compared with the allowable range a stable value, and that has fewer false alarms. It is in.

[Means to solve the problem]

In order to achieve the above object, the degassing state monitoring device for a die casting machine according to the present invention monitors the degassing state by detecting the flow rate of gas discharged from the mold cavity as molten metal is filled. The monitoring device includes a gas flow rate detector that detects the gas flow rate and outputs the detected value as flow rate data, and an injection rate detector that detects the injection rate of the molten metal and outputs the detected value as injection rate data. , and a control device that inputs the outputs of these detectors and performs predetermined calculation processing, and the control device determines a high-speed switching point from the injection speed data and performs high-speed switching from the injection start point based on the gas flow rate data. The area (a1) of the gas flow velocity curve up to the point,
The area (a2) of the gas flow velocity curve after the high-speed switching point is determined, and a correction constant (C1) is applied to these areas (al+a2).
, C2), and is configured to output an alarm signal when this sum (A) exceeds a preset tolerance range. It is characterized by:

In the above configuration of the present invention, with the start of the injection process, the gas flow rate detector sequentially detects the gas flow rate and outputs this as flow rate data to the next-stage control device. On the other hand, the injection speed detector preferably detects the moving speed of the injection plunger or the like using a magnetic sensor or the like, and outputs this as injection speed data to the control device.

The control device stores the input flow velocity data and injection velocity data, and determines the point at which the injection plunger starts moving at high speed, that is, the high speed switching point, based on the injection velocity data. After the high-speed switching point is defined, the area of the gas flow velocity curve from the injection start point to the high-speed switching point and the area of the gas flow velocity curve after the high-speed switching point are determined based on the flow velocity data, and a predetermined value is applied to these area values. Find the sum of the values obtained by multiplying by the correction constant. The sum obtained in this way is compared with a preset tolerance range, and if the sum deviates from the tolerance range, preferably an audible alarm or a warning light is turned on.

[Effect]

〔Example〕 Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows the overall configuration of a degassing state monitoring device for a die-casting machine according to this embodiment. In this figure, a cavity 3 is formed between the fixed mold l and the movable mold 2, and a gas vent passage 5 is formed which communicates with the cavity 3 and is open to the outside via a pool 4. ing.

A molten metal filling lower which communicates with the cavity 3 is formed in the fixed mold 1, and an injection sleeve 9 of an injection device 8 is inserted into this molten metal filling lower. A plunger 11 connected to a piston rod 10 is disposed within the injection sleeve 9, and the plunger 11 is provided so as to be movable in the axial direction via the piston rod 10 by supplying and discharging hydraulic pressure to the injection cylinder 12. The molten metal supplied from the molten metal supply port 14 formed in the injection sleeve 9? M15 is injected into the cavity 3 as the injection plunger 11 moves forward. A magnetic sensor 16 as an injection speed detector is arranged on the side of the piston rod 10 to detect the moving speed of the piston rod IO, that is, the injection speed, and the output of this magnetic sensor 16 is used as injection speed data for control described later. The information is input to the device 24.

Furthermore, a diffuser block I7 is placed at the open end of the gas vent passage 5. This differential user block 17 includes a first block 17A and a second block 17B, and these blocks 17A, 1
A gas release path 19 communicating with the gas vent flow path 5 is formed on the contact surface 18 of 7B.

A secondary original flow path 20 communicating with the gas discharge path 19 is formed in the first block 17A, and within this secondary original flow path 20, a wind speed sensor 21 constituting a gas flow speed detector is installed. is located. This wind speed sensor 21 detects the secondary flow wind speed generated in the secondary flow path 2o by the ejector action when the gas in the mold cavity 3 is released into the atmosphere through the gas release path 19. This makes it possible to detect wind speed, which is an indicator of the gas release state.

The output of the wind speed sensor 21 is inputted to the next stage control device 24 via an A/D converter 23. This control device 24 includes an input section 2 that inputs gas flow rate data outputted via the A/D converter 23 and injection speed data outputted from the magnetic sensor 16, respectively.
5, a storage section 26 that stores the gas flow rate data, injection speed data, and other set values input to the input section 25, and a calculation section that reads out the data stored in the storage section 26 and performs predetermined calculation processing. 27, and an output section 2 for outputting the output of the calculation section 27 to an external device.

A setting device 30 for setting various setting values such as allowable ranges is connected to the input section 25, and the setting values given by this setting device 30 are stored in the storage section 26. The output section 28 also includes a display 31, such as a CRT, that displays a curve of changes over time in gas flow velocity and injection speed as shown in FIG. An alarm device 32 that issues an audio alarm in response to an alarm signal output from the output section 28 and an alarm light 33 consisting of a red lamp or the like are connected.

Note that the symbol S in FIG. 2 indicates the injection start point, and the symbol ■ indicates the injection completion point.

Next, the operation of this embodiment will be explained with reference to FIGS. 2 and 3.

In the initial setting work, first, as shown in the injection speed curve C of Fig. 2 (A), the low injection speed V+ is 1.5
The point of Vl is defined to be the high speed switching point U, and this condition is stored in the storage section 26 via the setting device 30.

Now, when the die casting machine is started, the moving speed of the piston rod 10 of the injection device 8, that is, the injection speed is detected by the magnetic sensor 16, and the detected value, speed data, is sequentially stored in the storage section 26 via the input section 25. At the same time as being stored, a curve C representing the detected speed change over time is displayed on the display 31 via the output section 28 in the manner shown in FIG. 2(A). On the other hand, with the start of injection, the gas in the mold cavity 3 is released from the gas release path 19.
At this time, the secondary flow generated in the secondary source flow path 20 is detected by the wind speed sensor 21, and gas flow speed data, which is the detected value, is stored in the storage section 26, and the same as the injection speed. Gas flow velocity curve B is displayed on the display 31 in a manner as shown in FIG. 2(B).

Here, the gas flow rate data and injection speed data stored in the storage unit 26 are read out by the calculation unit 27, and the calculation unit 27 defines the gas flow rate curve B up to the high speed switching point U. Area al of the region and area a2 of the region defined by the gas flow velocity curve and B after the high speed switching point U
is required.

The correction constant C is added to the area al+a2 obtained in this way.
+, multiply by C2 and get AI-(at×Cz)
, A2 = (a, x C2), and calculate their sum A-(At + A2). Then, when this sum A is appropriate by determining the appropriate degassing state from the properties of the cast product, it is defined as a control value, and based on the sum A, an upper limit value AU and a lower limit value AL are set. is set using the setting device 30, and the initial setting work is completed.

Thereafter, for each casting cycle, the above-mentioned sum A is determined, and whether or not this sum A is within the permissible range of the upper and lower limits AU and AL is individually determined according to the above-described process.

Here, when the sum A deviates from the allowable range, an alarm signal is outputted from the output section 28 according to the output of the calculation section 27, the alarm device 32 is activated, and a warning light is simultaneously or selectively turned on. As a result, the operator can
Necessary maintenance and inspection work can be performed to eliminate blockages, etc.

According to this embodiment as described above, there are the following effects.

In other words, in the past, the determination was made based on whether the maximum value of the detected gas flow velocity was within the allowable range, but in this embodiment, the determination is made based on the gas flow velocity curves before and after the high speed switching point U. This structure calculates the area where the gas flow velocity curve B changes, calculates the sum by multiplying these by the necessary correction constant, and compares it with a preset tolerance range. This makes it possible to determine abnormalities, minimizes the number of erroneous determinations caused by variations in temporal changes in the conventional example, and has the effect of allowing highly accurate monitoring of the degassing state.

This gives high reliability to the target value compared with the allowable range, so the allowable range can be set narrowly, and from this point of view as well, it is possible to monitor the degassing state with high precision.

Further, in the embodiment, the wind speed sensor 21 is connected to the gas discharge path 1.
It does not directly measure the gas flow rate released from 9,
Since the configuration is such that an ejector action is generated in the secondary source flow path and the wind speed at this time is detected, there is no possibility that the molten metal will be ejected to the wind speed sensor 21 and adhere to the wind speed sensor 21, and the wind speed sensor The detection accuracy of 2I itself can also be maintained stably at all times.

In the above embodiment, the high-speed switching point U was explained as 1.5 times the low-speed injection speed V1, but the present invention is not necessarily limited to this. It is changed as appropriate depending on the time lag with the switching signal, etc.

Furthermore, when an abnormality is determined based on the comparison result in the calculation unit 27, an alarm is issued immediately, but the alarm is issued only when it is determined that the result is outside the allowable range several times in a row. You can.

Alternatively, there may be a second
It is also possible to set upper and lower limit values for , and to issue an alarm on condition that the determination value falls between the AU, AL and the second upper and lower limit values consecutively a plurality of times. In the case of such a configuration, it becomes possible to predict signs of abnormality before a defective product is actually manufactured, and there is an added effect that necessary inspections can be carried out at this time.

Furthermore, although it has been explained that the alarm signal is generated when the sum A of the numerical values AI and A2 deviates from the permissible range, a permissible range is set separately for each of the numerical values AI and A2, An alarm signal may be generated when these exceed the permissible range.

〔Effect of the invention〕

As explained above, according to the present invention, the degassing state can be monitored with high precision by setting the value to be compared with the allowable range to a stable value, and the degassing state of a die casting machine can be monitored with less false alarms. equipment can be provided.

3... Cavity, 5... Gas vent flow path, 8...
Injection device, 11... Injection plunger, 16... Magnetic sensor as injection speed detection means, 17... Defuser block, 19... Gas discharge path, 21... Gas flow rate detector Wind speed sensor, 24...control device,
31...Display device, 32...Alarm device.

Claims (1)

[Claims] (1) In a degassing state monitoring device that monitors the degassing state by detecting the flow rate of gas discharged from the mold cavity as molten metal is filled, the gas flow rate is detected and the detected value is converted into flow rate data. an injection speed detector that detects the injection speed of the molten metal and outputs the detected value as injection speed data, and a control device that inputs the output of each of these detectors and performs predetermined calculation processing. The control device determines a high-speed switching point from the injection speed data, and calculates an area (a_1) of a gas flow velocity curve from the injection start point to the high-speed switching point and an area (a_1) after the high-speed switching point based on the gas flow rate data. an arithmetic unit that calculates the area (a_2) of the gas flow velocity curve, respectively multiplies these areas (a_1, a_2) by correction constants (C_1, C_2), and calculates the sum (A) of the obtained values, A degassing state monitoring device for a die-casting machine, characterized in that it is configured to output an alarm signal when this sum (A) exceeds a preset allowable range.