Method for detecting molten metal in a mold

Abstract

To provide a method for detecting molten metal in a mold that allows for a more accurate understanding of the movement of molten metal within the mold. [Solution] The method for detecting molten metal inside a mold involves attaching multiple ultrasonic sensors to the outside of the mold, measuring the ultrasonic waveform at a specific location inside the mold with each ultrasonic sensor (S11), and detecting the position of the molten metal from the changes in the waveforms of the multiple ultrasonic sensors (S12, S13, S14).

Description

Technical Field

[0001] The present invention relates to a method for detecting molten metal in a mold.

Background Art

[0002] Patent Document 1 discloses a valve that opens and closes a communication path between a cavity and a vacuum tank, a first sensor element provided outside the in-mold space that repeatedly transmits ultrasonic waves to the in-mold space side and receives the reflected ultrasonic waves, and a control device that determines whether or not the molding material has reached a first position in the in-mold space based on the ultrasonic waves received by the first sensor element when injecting the molding material into the cavity with the valve open, and closes the valve when it is determined that the molding material has reached the first position. A molding machine with a mold is described.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, depending on the internal structure of the mold, it is difficult to accurately grasp the movement of the molten metal by simply detecting whether the molten metal has reached a predetermined position with an ultrasonic sensor.

Means for Solving the Problems

[0005] A method for detecting molten metal in a mold according to an embodiment attaches a plurality of ultrasonic sensors outside the mold, and detects the position of the molten metal from changes in the waveforms of the plurality of ultrasonic sensors.

Effects of the Invention

[0006] According to the method for detecting molten metal in a mold of the present disclosure, the movement of the molten metal in the mold can be grasped more accurately. [Brief explanation of the drawing]

[0007] [Figure 1] This flowchart shows an example of a method for detecting molten metal in a mold according to Embodiment 1. [Figure 2] This is a cross-sectional view of a mold to which the molten metal detection method in the mold according to Embodiment 1 applies. [Figure 3] This graph shows the waveform of the ultrasonic waves detected by the molten metal detection method in the mold according to Embodiment 1. [Figure 4] This is a cross-sectional view of a mold to which the molten metal detection method in the mold according to Embodiment 1 applies. [Figure 5] This graph shows the waveform of the ultrasonic waves detected by the molten metal detection method in the mold according to Embodiment 1. [Figure 6] This is a cross-sectional view showing the sensor configuration attached to the mold in the molten metal detection method in the mold according to Embodiment 2. [Modes for carrying out the invention]

[0008] Embodiment 1 Embodiments of the present invention will be described below with reference to the drawings. Figure 1 is a flowchart showing an example of a detection method according to Embodiment 1.

[0009] First, in step S11, an ultrasonic sensor attached to the outside of the mold measures the ultrasonic waves inside the mold. Then, the process proceeds to step S12.

[0010] In step S12, it is determined whether or not there is a change in the measured ultrasonic waveform. If there is no change in the measured ultrasonic waveform, proceed to step S13. If there is a change in the measured ultrasonic waveform, proceed to step S14.

[0011] In step S13, it is determined that the molten metal has not reached the position where the ultrasonic sensor is attached. Figure 2 is a cross-sectional view of the mold to which the detection method according to Embodiment 1 applies. As shown in Figure 2, if the molten metal 22 has not reached the position where the ultrasonic sensor 21 is attached, the waveform detected by the ultrasonic sensor 21 will be as shown in Figure 3. Figure 3 is a graph showing the ultrasonic waveform detected by the detection method according to Embodiment 1. In Figure 3, the horizontal axis represents time, and the vertical axis represents the amplitude of the signal detected by the ultrasonic sensor 21.

[0012] Step S14 determines that the molten metal has reached the position where the ultrasonic sensor is attached. Figure 4 is a cross-sectional view of the mold to which the detection method according to Embodiment 1 applies. As shown in Figure 4, when the molten metal 22 has reached the position where the ultrasonic sensor 21 is attached, the waveform detected by the ultrasonic sensor 21 is as shown in Figure 5.

[0013] Figure 5 is a graph showing the waveform of the ultrasonic wave detected by the detection method according to Embodiment 1. In Figure 5, the horizontal axis represents time, and the vertical axis represents the amplitude of the signal detected by the ultrasonic sensor 21.

[0014] Compared to Figure 3, in Figure 5, the amplitude of the reflected echo 51 has decreased from 1 to 0.8. Also, compared to Figure 3, a transmitted echo 52 appears in Figure 5, which was not present in Figure 3.

[0015] The change in the ultrasonic waveform indicates that the molten metal 22 has reached the position where the ultrasonic sensor 21 is attached.

[0016] The above measurements may be repeated. In addition, multiple ultrasonic sensors can be attached outside the mold to measure the flow rate of the molten metal. FIG. 6 is a cross-sectional view showing the sensor form attached to the mold by the detection method according to Embodiment 2. Based on the arrival times of the molten metal 22 at the multiple ultrasonic sensors 21-1 to 21-4 and the positions of the ultrasonic sensors 21-1 to 21-4, the distance between the positions of the molten metal corresponding to the multiple ultrasonic sensors and the difference in the arrival times of the molten metal 22 at the multiple ultrasonic sensors 21-1 to 21-4 are used to obtain the flow rate of the molten metal.

[0017] Thus, according to the method for detecting the molten metal in the mold of Embodiment 1, the movement of the molten metal in the mold can be grasped more accurately.

[0018] Also, according to the method for detecting the molten metal in the mold of Embodiment 1, the flow rate of the molten metal can be grasped by installing multiple ultrasonic sensors. Moreover, it can be utilized for the actual machine identification (comparison with the actual machine phenomenon) of the flow analysis of the molten metal in CAE (Computer Aided Engineering).

[0019] Note that the present invention is not limited to the above embodiments, and can be appropriately modified without departing from the gist. For example, instead of the molten metal, it may be applied to resin molding processes or core molding using liquids.

Description of Reference Numerals

[0020] 21, 21-1 to 21-4 Ultrasonic sensors 22 Molten metal

Claims

1. Multiple ultrasonic sensors are attached to the outside of the mold. Each ultrasonic sensor measures the ultrasonic waveform at a specific location inside the mold. A method for detecting molten metal in a mold, which detects the position of molten metal from changes in the waveforms of multiple ultrasonic sensors.

2. A method for detecting molten metal in a mold according to claim 1, wherein the flow velocity of the molten metal is detected from changes in the ultrasonic waveforms of each of the multiple ultrasonic sensors.

3. The method for detecting molten metal in a mold according to claim 1, wherein the change in the waveform of the ultrasonic sensor is determined by the attenuation of reflected echoes.

4. The method for detecting molten metal in a mold according to claim 1, wherein the change in the waveform of the ultrasonic sensor is determined by the appearance of transmitted echoes.

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