Fluid detection device and fluid detection method

Abstract

To detect fluids inside a mold without modifying the mold itself. [Solution] The fluid detection device according to the present disclosure comprises a mold that forms a cavity corresponding to the shape of a product, an opposing component positioned at a predetermined location opposite to the fluid flowing through the cavity, an ultrasonic sensor provided on the side of the opposing component opposite to the side facing the fluid, and a measuring device that determines when the molten metal has reached a predetermined position based on the change in the ultrasonic waveform of the ultrasonic sensor. The opposing component is at least one of a replaceable insert of the mold, an ejector pin that protrudes toward the cavity when removing the product from the cavity, and a cast-out pin that is inserted into the cavity from the opening of the cavity.

Description

Technical Field

[0001] The present disclosure relates to a fluid detection device and a fluid detection method.

Background Art

[0002] Patent Document 1 discloses a molten metal detection device that detects molten metal flowing in a die-casting mold using a short-circuit type molten metal detection sensor. The molten metal detection sensor has a configuration in which conduction between a core and a case is insulated by an insulator and is embedded in the mold. When moisture in the molten metal or mold release agent contacts the molten metal detection sensor, the core and the case are short-circuited and an electric current flows through the molten metal detection sensor.

[0003] The molten metal detection device of Patent Document 1 includes a photocoupler that detects the point when a predetermined reference value that is higher than the current value that flows when moisture in the mold release agent contacts the molten metal detection sensor and lower than the current value that flows when molten metal contacts the sensor is first reached. Thereby, it is possible to detect the tip of the molten metal flowing in the die-casting mold, distinguishing it from the case where the molten metal detection sensor is in a short-circuited state due to contact with moisture in the mold release agent.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In Patent Document 1, in order to embed the molten metal detection sensor in the mold, it is necessary to process the mold itself and attach the molten metal detection sensor.

[0006] The present disclosure has been made in view of such problems, and an object thereof is to provide a fluid detection device capable of detecting a fluid in a mold without modifying the mold. [Means for solving the problem]

[0007] The fluid detection device according to this disclosure comprises a mold that forms a cavity corresponding to the shape of a product; a counter component positioned at a predetermined location opposite to the fluid flowing through the cavity; an ultrasonic sensor provided on the surface of the counter component opposite to the surface facing the fluid; and a measuring device that determines that the fluid has reached a predetermined position based on changes in the ultrasonic waveform of the ultrasonic sensor.

[0008] In the fluid detection device described above, the cavity is formed by a replaceable insert of the mold, and the opposing component is the insert.

[0009] In the fluid detection device described above, the opposing component is an ejection pin that protrudes toward the cavity when removing the product from the cavity.

[0010] In the fluid detection device described above, the opposing component is a cast pin that is inserted into the cavity from the opening of the cavity.

[0011] The fluid detection method according to this disclosure involves forming a cavity corresponding to the shape of a product using a mold, introducing a fluid into the cavity, acquiring an ultrasonic waveform from an ultrasonic sensor provided on the side of an opposing component, which is positioned at a predetermined location opposite to the fluid flowing through the cavity, and determining, based on the change in the ultrasonic waveform, that the fluid has reached the predetermined position using a measuring device. [Effects of the Invention]

[0012] According to this disclosure, it is possible to detect fluids inside a mold without modifying the mold. [Brief explanation of the drawing]

[0013] [Figure 1]This figure shows a partial configuration of a die-casting apparatus to which the fluid detection device according to the embodiment is applied. [Figure 2] This figure shows a partial configuration of the die-casting apparatus 1 to which the fluid detection device 10 according to the embodiment is applied. [Figure 3] This graph shows the ultrasonic waveform before the molten metal reaches the detection position of the ultrasonic sensor. [Figure 4] This graph shows the ultrasonic waveform when the molten metal reaches the detection position of the ultrasonic sensor. [Figure 5] This is a flowchart illustrating the fluid detection method according to the embodiment. [Figure 6] This figure shows a partial configuration of a die-casting apparatus to which the fluid detection device according to the embodiment is applied. [Modes for carrying out the invention]

[0014] Embodiments of this disclosure will be described below with reference to the drawings. For clarity of explanation, the following descriptions and drawings have been omitted and simplified as appropriate. In addition, the same elements are denoted by the same reference numerals in each drawing, and redundant explanations have been omitted where necessary.

[0015] The embodiment relates to a fluid detection device capable of detecting fluids within a mold. The fluid detection device according to the embodiment can be used to detect various fluids, such as the flow of molten metal during casting, the flow of resin during injection molding, and the flow of slurry-like mixed material when molding a core to be placed inside a mold.

[0016] The following describes an example of detecting molten metal as an example of a fluid in a die-casting apparatus using a fluid detection device. A die-casting apparatus is a device that solidifies molten metal to manufacture a product having a predetermined shape. A die-casting apparatus is a device to which a casting method called vacuum die-casting or reduced-pressure die-casting is applied. That is, a die-casting apparatus manufactures a product by pouring molten metal into a cavity that has been reduced in pressure by a reduced-pressure device. The type of molten metal is not particularly limited, but for example, molten metal made of aluminum alloy is preferably used.

[0017] The die-casting device mainly comprises a mold, an injection device, a decompression device, and a fluid detection device (all not shown in the figure). The mold has a fixed mold and a movable mold. The fixed mold is a member fixed at a predetermined position. The fixed mold has a fixed-side insert and a fixed-side main mold. The fixed-side insert is a member forming the part that actually contacts the molten metal in the fixed mold. A cavity surface is formed on the mating surface of the fixed-side insert.

[0018] The movable mold is a member that moves relative to the fixed mold. The movable mold has a movable-side insert and a movable-side main mold. The movable-side insert is a member forming the part that actually contacts the molten metal in the movable mold. A cavity surface is formed on the mating surface of the movable-side insert.

[0019] In the fixed mold and the movable mold, since the insert and the main mold are separate bodies respectively, even if the insert is damaged due to contact with the molten metal, only the insert can be replaced. Thereby, compared with the case where the insert and the main mold are integrated, the cost related to the die-casting device can be reduced.

[0020] By closing the mold, that is, in a state where the mating surface of the fixed mold and the mating surface of the movable mold are in contact, a cavity corresponding to the shape of the product is formed inside the mold. The cavity surfaces of the fixed-side insert and the movable-side insert form the outer shape of the cavity. The cavity corresponds to the shape of the molded product.

[0021] The injection device is a device that supplies molten metal to the cavity of the mold. The injection device has an injection sleeve, a plunger, and an injection cylinder (not shown in the figure). The injection sleeve is provided with a pouring port (not shown) into which the molten metal is injected. The molten metal injected from the pouring port passes through the flow paths formed in the fixed-side main mold and the fixed-side insert from the injection sleeve and is introduced into the cavity.

[0022] A plunger is installed inside the injection sleeve. The plunger slides in a liquid-tight manner against the inner surface of the injection sleeve. The plunger is connected to an injection cylinder. The injection cylinder is a hydraulic cylinder that slides the plunger along the inner surface of the injection sleeve. The driving force of the injection cylinder causes the plunger to move forward or backward within the injection sleeve. As the plunger moves forward within the injection sleeve, the molten metal injected into the injection sleeve is injected into the cavity.

[0023] During casting, the fixed mold and the movable mold are first brought close together to create a clamped mold, forming a cavity between them. Next, molten metal is poured into the formed cavity and cooled to below its solidification temperature. This causes the molten metal to solidify, forming the product. After the product is formed, the fixed mold and the movable mold are separated to open the mold, and the product is removed.

[0024] An ejector pin is an example of an opposing component positioned in a predetermined location opposite to the molten metal flowing through a cavity. An ejector pin can also be described as an extraction member used to remove a product from the cavity. For example, the ejector pin is slidably housed in a housing hole provided in a movable mold. The ejector pin moves within the housing hole between a retracted position where its tip does not protrude into the cavity and an extraction position where its tip protrudes into the cavity. Moving the ejector pin to the extraction position causes the product to be pushed out of the cavity by the tip of the ejector pin. The tip of the ejector pin faces the molten metal.

[0025] Depending on the size and shape of the cavity, multiple ejection pins may be provided. Furthermore, the ejection pins may be positioned as fixed rather than movable, or as both movable and fixed.

[0026] The movable type has a flow path formed to reduce the pressure inside the cavity. The pressure reducing device is connected to the flow path by piping. The pressure reducing device mainly includes a pressure reducing pump and a pressure reducing valve. A pressure reducing valve is installed in the flow path. When the pressure inside the cavity is reduced, the pressure reducing valve is opened, and the air inside the cavity is discharged by the pressure reducing pump.

[0027] A die-casting apparatus is equipped with a fluid detection device to detect molten metal flowing inside the die-casting mold. Figures 1 and 2 show a partial configuration of the die-casting apparatus 1 to which the fluid detection device 10 according to the embodiment is applied. Figure 1 shows the state before the molten metal 30 reaches the detection position of the ultrasonic sensor 11, and Figure 2 shows the state when the molten metal 30 reaches the detection position of the ultrasonic sensor 11.

[0028] The molten metal 30 inside the mold 20 of the die-casting apparatus 1 is at a high temperature, and since the molten metal 30 is supplied under a reduced pressure environment, the flow of the molten metal 30 is a short-lived phenomenon. Furthermore, since the mold 20 is made of a metal such as heat-resistant alloy steel, the molten metal 30 inside the mold 20 cannot be directly observed, making it very difficult to grasp the phenomenon of the molten metal 30 flowing. In this embodiment, a technology is provided that makes it possible to easily detect the molten metal 30 inside the mold 20 without embedding a detection sensor in the mold.

[0029] As shown in Figures 1 and 2, the fluid detection device 10 mainly comprises an ultrasonic sensor 11 and a measuring device 12. The ultrasonic sensor 11 is provided on the side of the ejection pin 24 opposite to the side facing the molten metal 30. That is, the ultrasonic sensor 11 is attached to the rear end of the ejection pin 24. In this way, according to this embodiment, the ultrasonic sensor 11 can be retrofitted to the rear end of the ejection pin 24 without modifying the mold itself.

[0030] The ultrasonic sensor 11 mainly comprises a transmitting circuit and a receiving circuit. The transmitting circuit transmits ultrasonic waves (hereinafter also referred to as transmitted waves) for detecting molten metal. The transmitted waves propagate through the extrusion pins 24 and reach the cavity 23 through which the molten metal 30 flows. The receiving circuit receives ultrasonic waves reflected at the boundary between media with different acoustic impedances (hereinafter also referred to as reflected waves), as well as ultrasonic waves that have passed through the boundary (hereinafter referred to as transmitted waves).

[0031] The measuring device 12 determines that the molten metal 30 has reached a predetermined position (hereinafter referred to as the detection position) based on the change in the ultrasonic waveform of the ultrasonic sensor 11. In the example shown in Figure 1, the transmitted wave is reflected at the interface between the extrusion pin 24 and the space inside the cavity 23. In the example shown in Figure 2, the transmitted wave is reflected at the interface between the extrusion pin 24 and the molten metal 30. Since the acoustic impedance of the space inside the cavity 23 and the molten metal 30 are different, the ultrasonic waveform will be different before and when the molten metal 30 reaches the detection position of the ultrasonic sensor 11.

[0032] Figure 3 is a graph showing the ultrasonic waveform before the molten metal 30 reaches the detection position of the ultrasonic sensor 11. Figure 4 is a graph showing the ultrasonic waveform when the molten metal 30 reaches the detection position of the ultrasonic sensor 11. Comparing Figure 3 and Figure 4, it can be seen that when the molten metal 30 reaches the detection position of the ultrasonic sensor 11, the reflected echo is attenuated and the transmitted echo appears. The measuring device 12 can determine that the molten metal 30 has reached the detection position based on these changes in the ultrasonic waveform, such as the attenuation of the reflected echo and the appearance of the transmitted echo.

[0033] Here, with reference to Figure 5, a fluid detection method according to an embodiment will be described. As described above, when manufacturing a product, a cavity 23 corresponding to the shape of the product is formed by a mold 20, and molten metal 30 is introduced into the cavity 23. An ejector pin 24 is positioned at a detection location opposite to the molten metal 30 flowing through the cavity 23. An ultrasonic sensor 11 is provided on the side of the ejector pin 24 opposite to the side facing the molten metal 30.

[0034] In the fluid detection method according to the embodiment, first, the measuring device 12 acquires an ultrasonic waveform from the ultrasonic sensor 11 described above (step S1). Then, the measuring device 12 determines whether or not the acquired ultrasonic waveform has changed (step S2). If the ultrasonic waveform does not change (step S2NO), the measuring device 12 determines that the molten metal 30 has not reached the detection position (S3). If the ultrasonic waveform has changed (step S2YES), the measuring device 12 determines that the molten metal 30 has reached the detection position (S4).

[0035] As described above, in this embodiment, by providing an ultrasonic sensor 11 at the rear end of the ejection pin 24 facing the molten metal 30 flowing through the cavity 23, it is possible to determine the moment when the molten metal 30 reaches a detection position inside the mold 20, which is otherwise invisible, based on changes in the ultrasonic waveform. The phenomenon indicating the flow of the molten metal 30 in the actual machine, as determined in this way, can be used, for example, to compare with the results of flow analysis of the molten metal 30 using CAE (Computer-Aided Engineering).

[0036] Figure 6 shows a partial configuration of a die-casting apparatus 1 to which the fluid detection device 10 according to an embodiment is applied. Figure 6 shows an example in which a plurality of ejection pins 24 are provided. As shown in Figure 6, an ultrasonic sensor 11 may be provided at the rear end of each of the plurality of ejection pins 24. By providing a plurality of ultrasonic sensors 11 in this way, it becomes possible to grasp the flow velocity of the molten metal 30 in the cavity 23.

[0037] Although the present disclosure has been described above with reference to embodiments, the present disclosure is not limited to the embodiments described above. Various modifications to the structure and details of the present disclosure can be understood by those skilled in the art within the scope of the present disclosure.

[0038] Furthermore, the fluid detection method according to this embodiment can be applied not only to the flow of molten metal 30 during casting, but also to the visualization of various fluid flows, such as the flow of resin during injection molding and the flow of slurry-like mixed material when molding a core to be placed inside a mold.

[0039] In the above-described embodiment, an example was given in which the ultrasonic sensor 11 is provided on the ejection pin 24, but the placement of the ultrasonic sensor 11 is not limited to this example. For example, the ultrasonic sensor may be provided on a replaceable insert of the mold. The ultrasonic sensor may be provided on a punch pin that is inserted into an open cavity used when manufacturing cylindrical or bag-shaped bushings. That is, the opposing component may be a replaceable insert of the mold, an ejection pin that protrudes toward the cavity when removing the product from the cavity, a punch pin that is inserted into the cavity from the opening of the cavity, or a combination thereof. [Explanation of symbols]

[0040] 1. Die casting apparatus 10. Fluid detection device 11. Ultrasonic Sensor 12 Measuring devices 20 molds 21 Movable type 22 Fixed type 23 Cavity 24 ejection pins 30 molten metal

Claims

1. A mold that forms a cavity corresponding to the shape of the product, A counter component is positioned at a predetermined location opposite to the fluid flowing through the cavity, An ultrasonic sensor is provided on the surface of the opposing component opposite to the surface facing the fluid, A measuring device that determines when the fluid has reached a predetermined position based on the change in the ultrasonic waveform of the ultrasonic sensor, Equipped with, Fluid detection device.

2. The cavity is formed by a replaceable insert of the mold, The opposing component is the insert, The fluid detection device according to claim 1.

3. The opposing component is an ejector pin that protrudes toward the cavity when removing the product from the cavity. The fluid detection device according to claim 1.

4. The opposing component is a casting pin that is inserted into the cavity through the opening of the cavity. The fluid detection device according to claim 1.

5. A cavity corresponding to the shape of the product is formed by a mold, a fluid is introduced into the cavity, and an ultrasonic waveform is acquired from an ultrasonic sensor provided on the side of a counter component, which is positioned at a predetermined location opposite to the fluid flowing through the cavity, on the side opposite to the side facing the fluid. The measuring device determines that the fluid has reached a predetermined position based on the change in the ultrasonic waveform. A method for detecting fluids.

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