Monitoring device and monitoring method

Abstract

A monitoring device is provided with: an acquisition unit that acquires acceleration information of a plunger during injection operation; a determination unit that determines that there is an abnormality in a drive mechanism that drives the plunger when the fluctuation range of the acceleration of the plunger in the advancing direction exceeds a predetermined value and when the fluctuation frequency of the acceleration of the plunger in the advancing direction includes a component of a predetermined frequency; and an output unit that outputs the determination result of the determination unit.

Description

Technical Field

[0001] This invention relates to a monitoring device and a monitoring method. Background Technology

[0002] To produce high-quality molded products, die-casting machines, also known as die-casting apparatuses, require the inspection and rapid repair of various abnormalities affecting the plunger injection of molten metal. Technology concerning die-casting apparatuses is disclosed, for example, in Japanese Patent Application Publication No. 2020-138209.

[0003] Regarding the die-casting apparatus disclosed in Japanese Patent Application Publication No. 2020-138209, at least one of the injection sleeve, plunger head, and plunger rod is equipped with an accelerometer capable of detecting acceleration in three axial directions. The chatter (vibration) caused by seizing (wear) of the injection sleeve or plunger head is detected by the vertical acceleration detected by the accelerometer. Summary of the Invention

[0004] Abnormalities affecting plunger injection molten metal include not only seizure but also abnormalities in the drive mechanism that drives the plunger. However, Japanese Patent Application Publication No. 2020-138209 addresses the issue of being unable to detect abnormalities other than seizure among those affecting plunger injection molten metal.

[0005] The present invention was made in view of the above background, and provides a monitoring device and monitoring method capable of determining the location of abnormalities affecting plunger injection molten molten material.

[0006] The monitoring device involved in this invention comprises:

[0007] The acquisition unit acquires the acceleration information of the plunger during the injection action;

[0008] The determination unit determines that the drive mechanism driving the plunger is malfunctioning if the amplitude of the acceleration variation of the plunger in the thrust direction exceeds a predetermined value, and if the frequency of the acceleration variation of the plunger in the thrust direction includes a predetermined frequency component.

[0009] The output unit outputs the determination result of the determination unit. The monitoring device according to the present invention can detect abnormalities in the drive mechanism of the driving plunger with high precision. That is, the monitoring device according to the present invention can detect abnormalities other than sticking among those affecting the plunger injection molten metal. Based on the monitoring results of the monitoring device according to the present invention, the die-casting machine can repair the abnormal parts as needed, thus forming high-quality molded products.

[0010] The monitoring method involved in this invention includes the following steps:

[0011] Obtain the acceleration information of the plunger during the injection process;

[0012] If the amplitude of the acceleration of the plunger in the thrust direction exceeds a predetermined value, and if the frequency of the acceleration variation of the plunger in the thrust direction includes a predetermined frequency component, it is determined that the drive mechanism driving the plunger is malfunctioning; and

[0013] The result of the determination is output. The monitoring method involved in this invention can detect abnormalities in the drive mechanism of the driving plunger with high precision. That is, the monitoring method involved in this invention can detect abnormalities other than sticking among those affecting the plunger injection molten metal. Based on the monitoring results of the monitoring method involved in this invention, the die-casting machine can repair the abnormal parts as needed, thus forming high-quality molded products.

[0014] This invention provides a monitoring device and method for determining the location of abnormalities affecting plunger injection molten metal. Attached Figure Description

[0015] Hereinafter, with reference to the accompanying drawings, the features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described, in which the same reference numerals denote the same elements, and wherein:

[0016] Figure 1 This is a cross-sectional schematic diagram of a die-casting machine to which the monitoring device involved in this invention is applied.

[0017] Figure 2 This is a cross-sectional schematic diagram of a die-casting machine to which the monitoring device involved in this invention is applied.

[0018] Figure 3 This is a block diagram illustrating an example of the structure of the monitoring device involved in this invention.

[0019] Figure 4 It is a waveform diagram showing the acceleration of the plunger when there is an abnormality in the drive mechanism.

[0020] Figure 5 It is a waveform diagram showing the acceleration of the plunger when there is no abnormality in the drive mechanism.

[0021] Figure 6 It is a waveform diagram that magnifies a portion of the piston's acceleration when there is an abnormality in the drive mechanism.

[0022] Figure 7 It is a waveform diagram that magnifies a portion of the piston's acceleration when there is no abnormality in the drive mechanism.

[0023] Figure 8 It is a graph showing the spectrum of acceleration measurements during various acceleration measurements when there is an abnormality in the drive mechanism.

[0024] Figure 9 It is a graph showing the spectrum of each acceleration measurement period under the condition that there is no abnormality in the drive mechanism.

[0025] Figure 10 This is a flowchart illustrating the operation of the monitoring device involved in this invention. Detailed Implementation

[0026] Hereinafter, embodiments will be described with reference to the accompanying drawings. However, since the drawings are simplified, the technical scope of the embodiments should not be narrowly interpreted based on the description in the drawings. Furthermore, the same symbols are used to denote the same elements, and repeated descriptions are omitted.

[0027] Structure of Die Casting Machine 1

[0028] First, use Figure 1 and Figure 2 The structure of the die-casting machine using the monitoring device involved in this invention will be described. Figure 1 and Figure 2 This is a cross-sectional schematic diagram showing a die-casting machine 1 using the monitoring device according to the present invention. The die-casting machine 1 is a casting apparatus (so-called die-casting apparatus) that performs casting by injecting molten metal into a mold. Figure 1 The image shows die-casting machine 1 before the injection begins. Figure 2 The image shows the die-casting machine 1 after the injection process has just begun.

[0029] in addition, Figure 1 and Figure 2 The right-handed XYZ orthogonal coordinate system shown is for ease of illustrating the positional relationships of the constituent elements. The Z direction is the vertical direction, the XY plane is the horizontal plane, and the X, Y, and Z directions are common to each other in the attached figures.

[0030] like Figure 1 and Figure 2 As shown, the die-casting machine 1 includes a mold 11, an injection sleeve 12, and a plunger 13.

[0031] The mold 11 includes a moving mold 111 and a fixed mold 112. The moving mold 111 and the fixed mold 112 form a hollow space, i.e., a cavity C, by closing the mold. An opening communicating with the cavity C is provided in the fixed mold 112. The opening of the fixed mold 112 forms the inlet, i.e., the gate, of the cavity C and the flow path, i.e., the runner, for the molten metal M from the outside of the mold 11 to the gate. The molten metal M is, for example, molten aluminum.

[0032] The injection sleeve 12 is a cylindrical component. Figure 1 and Figure 2In this example, the injection sleeve 12 is configured to extend along the X direction. An opening 12a for supplying molten metal M from the outside to the inside of the injection sleeve 12 is provided on its upper surface. Furthermore, an injection port 12b for injecting molten metal M from the inside to the outside of the injection sleeve 12 is provided at its front end. The injection sleeve 12 and the fixed mold 112 are connected such that the injection port 12b of the injection sleeve 12 communicates with the opening of the fixed mold 112. Moreover, an insertion port for inserting a plunger 13 is provided at the rear end of the injection sleeve 12.

[0033] The plunger 13 is a rod-shaped component that is inserted into the interior of the injection sleeve 12 through an insertion port located at the rear end of the injection sleeve 12. The plunger 13 is configured to slide within the injection sleeve 12. Figure 1 and Figure 2 In this example, the plunger 13 is configured to slide in the X direction within the injection sleeve 12. For example, from Figure 1 The state of die-casting machine 1 before injection begins is shown in the image. Figure 2 As shown, the plunger 13 moves (advances) along the negative side of the X direction within the injection sleeve 12. As a result, the molten molten material M within the injection sleeve 12 is injected from the injection port 12b into the cavity C.

[0034] Specifically, the plunger 13 includes a plunger head 131 and a plunger rod 132. The plunger head 131 is a cylindrical component with a cross-sectional shape along the inner surface of the injection sleeve 12, and is inserted into the interior of the injection sleeve 12 through an insertion port provided at the rear end of the injection sleeve 12. One end face of the plunger head 131 is the surface that contacts the molten metal M supplied into the injection sleeve 12. The other end face of the plunger head 131 is connected to the front end of the rod-shaped plunger rod 132. The rear end of the plunger rod 132 is connected to a drive mechanism (not shown).

[0035] A drive mechanism (not shown) moves the plunger rod 132 in the X direction, thereby causing the plunger head 131 to slide in the X direction within the injection sleeve 12. For example, from Figure 1 The state of die-casting machine 1 before injection begins is shown in the image. Figure 2 As shown, a drive mechanism (not illustrated) moves the plunger rod 132 along the negative side of the X direction (advances). Consequently, the plunger head 131 slides (advances) along the negative side of the X direction within the injection sleeve 12. Thus, the molten metal M within the injection sleeve 12 is injected from the injection port 12b into the cavity C.

[0036] Alternatively, the drive mechanism for driving the plunger 13 can be, for example, a hydraulic cylinder whose drive output is controlled by a servo valve. The cylinder rod of the hydraulic cylinder is connected to the base end of the plunger rod 132 via a coupling. However, the drive mechanism for driving the plunger 13 is not limited to a hydraulic cylinder and can be any mechanism, as long as it is a mechanism that has the controllability to make the plunger 13 slide in the X direction and has the driving force to use the plunger 13 to inject the molten molten M in the injection sleeve 12 into the cavity C.

[0037] After the molten metal M is injected into the injection sleeve 12 and fills the cavity C, the molten metal M in the cavity C solidifies to form a molded product P. Then, the mold 11 is opened by moving the moving mold 111 along the negative side of the X direction. Furthermore, the molded product P is demolded from the fixed mold 112 by moving the plunger 13 further along the negative side of the X direction (advancing). After the molded product P is removed from the mold 11, the plunger 13 moves along the positive side of the X direction (retracting) and returns to the position before the injection started (injection start position). Furthermore, the moving mold 111 moves along the positive side of the X direction and returns to the position before the injection started. That is, the mold 11 returns to the closed state. Then, molten metal M for forming the next molded product P is supplied into the injection sleeve 12 through the opening 12a. This process is repeated in the die casting machine 1.

[0038] Typically, injection is performed at a low speed from the moment the molten metal M is extruded from the plunger 13 into the injection sleeve 12 until the molten metal M is vented and filled into the injection sleeve 12. Preferably, injection is performed at a low speed from the moment the molten metal M is extruded from the plunger 13 into the injection sleeve 12 until the molten metal M reaches the gate of the mold 11. Then, injection is performed at a high speed until the molten metal M fills the cavity C.

[0039] Here, an acceleration sensor S is also installed in the die-casting machine 1. Figure 1 and Figure 2 In this example, the acceleration sensor S is mounted near the front end of the plunger rod 132. Therefore, compared to the case where it is mounted on the plunger head 131, the acceleration sensor S can prevent degradation caused by heat from the molten metal M. However, the acceleration sensor S can also be mounted on the plunger head 131. In this case, compared to the case where it is mounted on the plunger rod 132, the acceleration sensor S can detect acceleration with higher accuracy.

[0040] Accelerometer S is a sensor capable of detecting acceleration in three axial directions. For example, accelerometer S detects the acceleration of plunger 13 in the propulsion direction (X direction) during injection, or detects the acceleration of plunger 13 in the direction perpendicular to the propulsion direction (parallel to the YZ plane) during injection.

[0041] Acceleration measurement by the accelerometer S can be performed continuously from the start of injection to the completion of injection, or it can be performed at any time. That is, acceleration measurement by the accelerometer S can be performed continuously during the period when the plunger head 131 moves from the injection start position to the injection completion position and then back to the injection start position within the injection sleeve 12. The acceleration measurement by the accelerometer S can be performed at any time. The injection start position is the position where the plunger head 131 begins to extrude the molten metal M within the injection sleeve 12, and the injection completion position is the position where the molten metal M completes its injection into the cavity C.

[0042] In this invention, the acceleration measurement by the acceleration sensor S is performed during the low-speed injection period from the start of the extrusion of the molten M into the injection sleeve 12 by the plunger 13 until the injection sleeve 12 is vented and filled with molten M. Preferably, the acceleration measurement by the acceleration sensor S is performed during the low-speed injection period from the start of the extrusion of the molten M into the injection sleeve 12 by the plunger 13 until the injection sleeve 12 is vented and filled with molten M.

[0043] In the die-casting machine 1, other sensors capable of detecting the acceleration of the plunger 13 in the propulsion direction (X direction) during the injection action can be installed instead of the acceleration sensor S. In the die-casting machine 1, other sensors capable of detecting the acceleration of the plunger 13 in the direction perpendicular to the propulsion direction (parallel to the YZ plane) during the injection action can also be installed.

[0044] Furthermore, in order to produce high-quality molded products, the die-casting machine 1 needs to detect and quickly repair various abnormalities affecting the injection molten material of the plunger 13. These abnormalities include not only seizure but also abnormalities in the drive mechanism that drives the plunger. However, in related technologies, there is a problem that abnormalities other than seizure affecting the injection molten material of the plunger 13 cannot be detected.

[0045] Therefore, the monitoring device according to the present invention utilizes the phenomenon that the drive mechanism of the drive plunger 13 continuously imparts vibrations of a predetermined frequency to the plunger 13 when an abnormality occurs. The monitoring device uses this phenomenon to monitor whether there is an abnormality in the drive mechanism based on the acceleration information of the plunger 13 in the propulsion direction. Thus, the monitoring device according to the present invention can detect abnormalities other than sticking among those affecting the injection molten metal of the plunger 13. That is, the monitoring device according to the present invention can determine the location of various abnormalities affecting the injection molten metal of the plunger. The die-casting machine 1 can repair the abnormal parts as needed based on the monitoring results of the monitoring device, thereby forming high-quality molded products. The structure of the monitoring device according to the present invention will be described below.

[0046] Structure of monitoring device 2

[0047] Figure 3 This is a block diagram illustrating a structural example of the monitoring device 2 according to the present invention. The monitoring device 2 is a device for monitoring the die-casting machine 1. In particular, the monitoring device 2 monitors whether there are any abnormalities in the drive mechanism (in this example, a hydraulic cylinder) of the drive plunger 13. In addition, the monitoring device 2 monitors whether there is any sticking (wear) or floating in the injection sleeve 12 or the plunger 13.

[0048] Additionally, "sticking" refers to the wear of the injection sleeve 12 or plunger 13. If wear progresses and molten metal enters and solidifies in the worn area, the friction of the solidified molten metal may prevent smooth movement of the plunger 13 within the injection sleeve 12. "Floating" refers to a state where smooth movement of the plunger 13 within the injection sleeve 12 is impossible due to a failure in the connection between the cylinder rod of the hydraulic cylinder and the base end of the plunger rod 132 via the coupling.

[0049] like Figure 3 As shown, the monitoring device 2 includes an acquisition unit 21, a determination unit 22, and an output unit 23.

[0050] The acquisition unit 21 acquires acceleration information of the plunger 13 during the injection action detected by the acceleration sensor S via a wired or wireless network. The acceleration information of the plunger 13 includes information related to the acceleration of the plunger 13 in the propulsion direction (X direction) during the injection action and information related to the acceleration of the plunger 13 in the direction perpendicular to the propulsion direction (parallel to the YZ plane) during the injection action.

[0051] The determination unit 22 determines whether there is any abnormality in the drive mechanism that drives the piston 13 based on the information related to the acceleration of the piston 13 in the propulsion direction (X direction) in the acquired acceleration information.

[0052] For example, if the variation in the acceleration of the plunger 13 in the thrust direction is less than or equal to a first predetermined value, the determination unit 22 determines that the drive mechanism driving the plunger 13 is not malfunctioning. The variation in the acceleration of the plunger 13 in the thrust direction is the amplitude of the waveform representing the acceleration of the plunger 13 in the thrust direction, i.e., the vibration of the plunger 13 in the thrust direction. Furthermore, the first predetermined value can be set, for example, based on the variation in acceleration obtained during normal injection. Alternatively, the first predetermined value can be set based on the average value of acceleration obtained during acceleration measurement. The first predetermined value can be fixed or can vary according to changes in the reference value.

[0053] In contrast, if the variation in the acceleration of the plunger 13 in the propulsion direction exceeds the first predetermined value, the drive mechanism driving the plunger 13 may be malfunctioning. Therefore, the determination unit 22 then performs frequency analysis on the acceleration of the plunger 13 in the propulsion direction.

[0054] For example, if a component of a predetermined frequency (e.g., approximately 40 Hz) is detected in the frequency variation of the acceleration of the plunger 13 in the thrust direction, the determination unit 22 determines that there is an abnormality in the drive mechanism driving the plunger 13. Conversely, if no component of the predetermined frequency is detected in the frequency variation of the acceleration of the plunger 13 in the thrust direction, the determination unit 22 determines that there is an abnormality other than in the drive mechanism driving the plunger 13. Furthermore, the predetermined frequency is set to a value corresponding to the injection conditions of the die-casting machine 1.

[0055] More preferably, if the determination unit 22 continuously detects a component of a predetermined frequency from the frequency of the acceleration variation of the plunger 13 in the propulsion direction during the acceleration measurement, it determines that there is an abnormality in the drive mechanism driving the plunger 13. In this example, the acceleration measurement period may be a low-speed injection period. The predetermined frequency may be, for example, approximately 40 Hz. Conversely, if the predetermined frequency component is not detected from the frequency of the acceleration variation of the plunger 13 in the propulsion direction during the acceleration measurement, the determination unit 22 determines that there is an abnormality other than in the drive mechanism driving the plunger 13. Alternatively, if the predetermined frequency component is detected from the frequency of the acceleration variation of the plunger 13 in the propulsion direction only for a portion of the acceleration measurement period, the determination unit 22 determines that there is an abnormality other than in the drive mechanism driving the plunger 13.

[0056] Furthermore, the determination unit 22 can also determine whether the injection sleeve 12 or the plunger 13 is stuck or floating based on the acceleration information obtained and the information related to the acceleration of the plunger 13 in the direction perpendicular to the propulsion direction. The direction perpendicular to the propulsion direction of the plunger 13 is the direction parallel to the YZ plane.

[0057] For example, if the variation in the acceleration of the plunger 13 in the direction perpendicular to the propulsion direction is less than or equal to a second predetermined value, the determination unit 22 determines that no abnormality of sticking or floating has occurred. The variation in the acceleration of the plunger 13 in the direction perpendicular to the propulsion direction is the amplitude of the waveform representing the acceleration of the plunger 13 in the direction perpendicular to the propulsion direction, that is, the vibration in the direction perpendicular to the propulsion direction of the plunger 13. Conversely, if the variation in the acceleration of the plunger 13 in the direction perpendicular to the propulsion direction exceeds the second predetermined value, the determination unit 22 determines that some kind of abnormality of sticking or floating has occurred. If some kind of abnormality of sticking or floating occurs, the die-casting machine 1 may be unable to achieve accurate injection action, and in this case, a defective molded product P may be formed.

[0058] The second specified value can be set, for example, based on the range of acceleration variation obtained during normal injection. Alternatively, the second specified value can be set based on the average value of acceleration obtained during acceleration measurement. The second specified value can be fixed or can vary according to changes in the reference value.

[0059] The determination unit 22 can consider not only the amplitude of the acceleration variation of the plunger 13 in the direction perpendicular to the propulsion direction, but also the frequency of the acceleration variation of the plunger 13 in the direction perpendicular to the propulsion direction. The determination unit 22 can consider these factors to determine whether there is seizing or floating. For example, if the amplitude of the acceleration variation of the plunger 13 in the direction perpendicular to the propulsion direction exceeds a second predetermined value, and the frequency of the acceleration variation of the plunger 13 in the direction perpendicular to the propulsion direction includes the second predetermined frequency, the following determination can be made. That is, in these cases, the determination unit 22 can determine that some kind of abnormality, such as seizing or floating, has occurred.

[0060] The second specified frequency can be set based on, for example, the frequency of acceleration variation acquired during normal injection. Alternatively, the second specified frequency can also be set based on the average value of the frequency of acceleration variation acquired during acceleration measurement.

[0061] Output unit 23 outputs the determination result of determination unit 22 as the monitoring result of monitoring device 2. The determination result of determination unit 22 is displayed, for example, on a display (not shown). Therefore, the operator of die-casting machine 1 can refer to the determination result displayed on the display and perform repairs, etc., on any abnormal drive mechanism as needed. The operator of die-casting machine 1 can refer to the determination result displayed on the display and perform repairs, etc., on any stuck injection sleeve 12 or plunger 13 as needed. The operator of die-casting machine 1 can refer to the determination result displayed on the display and perform repairs, etc., on any floating coupling as needed.

[0062] Alternatively, the output unit 23 may be configured to output an instruction corresponding to the determination result of the determination unit 22 to the control unit (not shown) of the die-casting machine 1. For example, if an abnormality is determined to have occurred in the die-casting machine 1, the output unit 23 outputs an instruction to stop the injection operation to the control unit of the die-casting machine 1. Thus, the control unit of the die-casting machine 1 stops the injection operation of the die-casting machine 1 according to the instruction from the monitoring device 2. After the injection operation of the die-casting machine 1 stops, the operator of the die-casting machine 1 can repair the abnormal part of the die-casting machine 1. Furthermore, the monitoring device 2 can also be used as part of the control unit of the die-casting machine 1.

[0063] Experimental results

[0064] Next, use Figures 4 to 9The experimental results of the injection action of die-casting machine 1 are explained. Furthermore, the acceleration of plunger 13 does not consider the component of gravitational acceleration.

[0065] Figure 4 This is a waveform diagram showing the acceleration of piston 13 when there is an abnormality in the drive mechanism. Figure 5 This is a waveform diagram showing the acceleration of piston 13 when there is no abnormality in the drive mechanism. Figure 4 and Figure 5 The diagram also shows the stroke of the plunger 13 (the distance of the plunger 13 from the injection start position) and the moving speed of the plunger 13.

[0066] exist Figure 4 In the example, the injection velocity changes slightly during low-speed injection. Furthermore, in Figure 4 In the example, the vibration of the plunger 13's acceleration in the propulsion direction and the vibration of the plunger 13's acceleration in the direction perpendicular to the propulsion direction are both linked to subtle changes in the injection velocity. That is, subtle changes in the injection velocity are caused by the vibration of the plunger 13's acceleration in the propulsion direction. Here, as... Figure 4 As shown, before the drive mechanism was repaired, the vibration of the plunger 13's acceleration in the thrust direction was greater than the first specified value. In contrast, as... Figure 5 As shown, after the drive mechanism is repaired, the vibration of the acceleration of the plunger 13 in the propulsion direction is suppressed to below a first predetermined value. Thus, when there is an abnormality in the drive mechanism, the variation in the acceleration of the plunger 13 in the propulsion direction is larger compared to when there is no abnormality in the drive mechanism.

[0067] Figure 6 It is a waveform diagram showing a portion of the acceleration of piston 13 under abnormal conditions of the drive mechanism. Figure 7 This is a magnified waveform showing a portion of the acceleration of piston 13 under conditions where the drive mechanism is functioning normally. Figure 6 and Figure 7 The image shows a portion of the waveform during low-speed injection.

[0068] If comparison Figure 6 and Figure 7 Regardless of whether the drive mechanism is malfunctioning, the magnitude of the acceleration variation of the plunger 13 in the direction perpendicular to the propulsion direction remains the same. However, the magnitude of the acceleration variation of the plunger 13 in the propulsion direction is greater when the drive mechanism is malfunctioning compared to when it is functioning correctly.

[0069] Figure 8 This is a graph showing the spectrum of acceleration measurements from T11 to T14 under the condition that there is an abnormality in the drive mechanism. Figure 9 This is a graph showing the spectrum of acceleration measurements from T21 to T24 under the condition that there is no abnormality in the drive mechanism. Figure 8 During the acceleration measurement period T11 to T14, and Figure 6 The acceleration measurement period corresponds to T11 to T14. Figure 9 During the acceleration measurement period from T21 to T24, and Figure 7 The acceleration measurement period corresponds to T21 to T24.

[0070] like Figure 8 As shown, in the event of an abnormality in the drive mechanism, a component of a specified frequency is continuously detected from the variation frequency of the acceleration of the plunger 13 in the thrust direction during acceleration measurement from T11 to T14. Figure 8 In the example, a specified frequency component of approximately 40 Hz with an amplitude of 0.1 mm or more was continuously detected during the acceleration measurement period T11 to T14. Furthermore, during most of the acceleration measurement period T11 to T14 (the period from T12 to T14), a specified frequency component of approximately 40 Hz with an amplitude of approximately 0.3 mm or more was detected. In contrast, as... Figure 9 As shown, assuming no abnormalities in the drive mechanism, no specified frequency component was detected in the frequency variation of the acceleration of the plunger 13 in the propulsion direction during acceleration measurement periods T21 to T24. Figure 9 In the example, a specified frequency component of approximately 40 Hz with an amplitude of 0.1 mm or more was detected only during the acceleration measurement period from T22 to T24 (T21 to T24). Furthermore, no specified frequency component of approximately 40 Hz with an amplitude of approximately 0.3 mm or more was detected during the acceleration measurement period from T21 to T24. Thus, in the case of an abnormality in the drive mechanism, compared to the case where the drive mechanism is not abnormal, a specified frequency component with a large amplitude is continuously detected from the frequency variation of the acceleration of the plunger 13 in the propulsion direction.

[0071] The operation of monitoring device 2

[0072] Next, use Figure 10 The operation of monitoring device 2 will be explained. Figure 10 This is a flowchart illustrating the actions of monitoring device 2.

[0073] First, the monitoring device 2 acquires the acceleration information of the plunger 13 during the injection action detected by the acceleration sensor S (S101). The acceleration information of the plunger 13 includes information related to the acceleration of the plunger 13 in the propulsion direction (X direction) during the injection action and information related to the acceleration of the plunger 13 in the direction perpendicular to the propulsion direction (the direction parallel to the YZ plane) during the injection action.

[0074] Then, based on the acceleration information of the plunger 13 in the propulsion direction, the monitoring device 2 determines whether there is any abnormality in the drive mechanism that drives the plunger 13 (S102).

[0075] For example, if the variation in the acceleration of the plunger 13 in the propulsion direction is less than or equal to the first predetermined value (S102 "No"), the monitoring device 2 determines that the drive mechanism driving the plunger 13 is normal (S103). Conversely, if the variation in the acceleration of the plunger 13 in the propulsion direction exceeds the first predetermined value (S102 "Yes"), the drive mechanism driving the plunger 13 may be abnormal. Therefore, the monitoring device 2 then performs frequency analysis on the acceleration of the plunger 13 in the propulsion direction (S104).

[0076] For example, if the monitoring device 2 continuously detects a component of a predetermined frequency from the frequency of the acceleration variation of the plunger 13 in the propulsion direction during acceleration measurement (S104 "Yes"), it makes the following determination. In this example, the acceleration measurement period is during low-speed injection. The predetermined frequency is, for example, approximately 40 Hz. If the monitoring device 2 detects a component of the predetermined frequency (S104 "Yes"), it determines that there is an abnormality in the drive mechanism driving the plunger 13 (S105). Conversely, if the monitoring device 2 does not detect a component of the predetermined frequency from the frequency of the acceleration variation of the plunger 13 in the propulsion direction during acceleration measurement (S104 "No"), it makes the following determination. If the monitoring device 2 does not detect a component of the predetermined frequency (S104 "No"), it determines that there is an abnormality other than in the drive mechanism driving the plunger 13 (S106). Alternatively, if the monitoring device 2 detects a component of a predetermined frequency from the frequency of the acceleration variation of the plunger 13 in the propulsion direction only during a portion of the acceleration measurement period ("No" in S104), the following determination is made: that is, the monitoring device 2 determines that there is an abnormality other than the drive mechanism that drives the plunger 13 (S106).

[0077] Then, based on the acceleration information of the plunger 13 in the direction perpendicular to the propulsion direction, the monitoring device 2 determines whether the injection sleeve 12 or the plunger 13 is stuck or floating (S107).

[0078] For example, if the variation in acceleration of the plunger 13 in the direction perpendicular to the propulsion direction is less than the second predetermined value ("No" in S107), the monitoring device 2 determines that no abnormality of seizing or floating has occurred (S108). Conversely, if the variation in acceleration of the plunger 13 in the direction perpendicular to the propulsion direction exceeds the second predetermined value ("Yes" in S107), the monitoring device 2 determines that some abnormality of seizing or floating has occurred (S109).

[0079] Then, the monitoring device 2 outputs a judgment result (S110). The judgment result is displayed on a monitor (not shown). Thus, the manager of the die-casting machine 1 can refer to the judgment result displayed on the monitor and perform repairs on the die-casting machine 1 as needed.

[0080] Alternatively, monitoring device 2 can output an instruction corresponding to the determination result to the control unit (not shown) of die-casting machine 1. For example, if an abnormality is determined to have occurred in die-casting machine 1, monitoring device 2 will output an instruction to stop the injection operation to the control unit of die-casting machine 1. Consequently, the control unit of die-casting machine 1 will stop the injection operation of die-casting machine 1 according to the instruction from monitoring device 2. After the injection operation of die-casting machine 1 stops, the operator of die-casting machine 1 can repair the abnormal part of die-casting machine 1. Furthermore, monitoring device 2 can also be used as part of the control unit of die-casting machine 1.

[0081] Thus, the monitoring device 2 of the present invention utilizes the phenomenon that the drive mechanism of the driving plunger 13 continuously imparts vibrations of a predetermined frequency to the plunger 13 when an abnormality occurs. The monitoring device 2 uses this phenomenon to monitor whether there is any abnormality in the drive mechanism based on the acceleration information of the plunger 13 in the propulsion direction. Therefore, the monitoring device 2 of the present invention can detect abnormalities other than sticking among those affecting the injection molten material of the plunger 13. That is, the monitoring device 2 of the present invention can determine the location of various abnormalities affecting the injection molten material of the plunger 13. Based on the monitoring results of the monitoring device 2, the die-casting machine 1 can repair the abnormal parts as needed, thereby forming a high-quality molded product P.

[0082] The present invention enables part or all of the processing in the monitoring device 2 or the die-casting machine 1 equipped with the monitoring device 2 to be realized by executing a computer program through a central processing unit (CPU).

[0083] When the above-described program is read into a computer, it includes a set of commands (or software code) for causing the computer to perform one or more functions described in the embodiments. The program may be stored in a non-transitory computer-readable medium or a physical storage medium. By way of example, and not limitation, a computer-readable medium or a physical storage medium includes random-access memory (RAM), read-only memory (ROM), flash memory, solid-state drive (SSD), or other memory technologies. By way of example, and not limitation, a computer-readable medium or a physical storage medium includes CD-ROM, digital versatile disc (DVD), Blu-ray disc (registered trademark), or other optical disc storage devices. By way of example, and not limitation, a computer-readable medium or a physical storage medium includes magnetic tape, magnetic tape, disk storage, or other magnetic storage devices. The program may be transmitted on a temporary computer-readable medium or a communication medium. By way of example, and not limitation, a temporary computer-readable medium or communication medium includes electrical, optical, acoustic, or other forms of propagation signals.

[0084] The present invention has been described above with reference to the embodiments described above, but the present invention is not limited to the above embodiments. Various modifications that can be understood by those skilled in the art can be made to the structure or details of the present invention within the scope of the present invention. Furthermore, each embodiment can be appropriately combined with other embodiments.

Claims

1. A monitoring device, characterized in that, have: The acquisition unit acquires the acceleration information of the plunger during the injection action; The determination unit determines that the drive mechanism driving the plunger is malfunctioning if the amplitude of the change in the acceleration of the plunger in the thrust direction exceeds a predetermined value, and if the frequency of the change in the acceleration of the plunger in the thrust direction contains a predetermined frequency component. and The output unit outputs the determination result of the determination unit.

2. The monitoring device according to claim 1, characterized in that, If the determination unit determines that the drive mechanism driving the plunger is malfunctioning when the amplitude of the plunger's acceleration in the propulsion direction exceeds the predetermined value, and if the frequency of the plunger's acceleration in the propulsion direction continuously includes a component of the predetermined frequency during the acceleration measurement, the determination unit determines that the drive mechanism driving the plunger is malfunctioning.

3. The monitoring device according to claim 2, characterized in that, Even if the magnitude of the change in the acceleration of the plunger in the propulsion direction exceeds the predetermined value, if the predetermined frequency component is included only in the frequency of the change in the acceleration of the plunger in the propulsion direction during a portion of the acceleration measurement period, or if the predetermined frequency component is not included in the frequency of the change in the acceleration of the plunger in the propulsion direction during the acceleration measurement period, the determination unit determines that there is an abnormality other than the drive mechanism that drives the plunger.

4. The monitoring device according to claim 1, characterized in that, Based on the acceleration information and the information related to the acceleration of the plunger in the direction perpendicular to the propulsion direction, the determination unit further determines whether at least one of the injection sleeve and the plunger is stuck.

5. A monitoring method, characterized in that, Includes the following steps: Obtain the acceleration information of the plunger during the injection process; If the magnitude of the acceleration variation of the plunger in the thrust direction exceeds a predetermined value, and if the frequency of the acceleration variation of the plunger in the thrust direction contains a predetermined frequency component, it is determined that the drive mechanism driving the plunger is abnormal. and Output the result of the determination.

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