JP5657355B2 - Die-casting machine and abnormality detection method for die-casting machine - Google Patents

Description

  The present invention relates to a die casting machine for injecting and filling a molten metal supplied into an injection sleeve into a mold by advancing an injection plunger, and particularly when a sliding resistance of a predetermined value or more occurs in the operation of an injection blanker. TECHNICAL FIELD The present invention relates to a die casting machine that detects a defect as an abnormality and a method for detecting an abnormality in a die casting machine.

  In a conventional die casting machine that has been used in the past, a metal material melted in a melting furnace is weighed and pumped by a ladle for each shot, and the molten metal is pumped into a hot water inlet of an injection sleeve and injected. The molten metal is injected and filled into the cavity of the mold at high speed and high pressure by the forward movement of the injection plunger provided in the sleeve so as to be able to advance and retreat, thereby forming the cast molded body.

  The injection process of a die-casting machine that injects molten metal into the mold cavity consists of a low-speed injection process followed by a high-speed injection process. It is necessary to inject and fill the molten metal into the mold at a high injection speed that is one digit faster than the speed. Therefore, as a drive source in the injection process, an electric servo motor is adopted as a drive source in the low-speed injection process, while a larger driving force is required in the high-speed injection process. By adding the driving force of the motor, high-speed injection filling is performed in the mold.

  By the way, a general die-casting machine repeatedly manufactures a cast molded body with its operation. When the operation is continued, when the injection plunger is advanced and retracted, the injection plunger that is advanced and retracted has a predetermined value or more. Sliding resistance may occur. The cause is that the remaining metal melt (melted residue such as Al) adheres to the inner wall surface of the injection sleeve and the outer peripheral surface of the injection plunger chip slidably disposed on the inner wall surface of the injection sleeve, Or, it is generated by so-called sag, seizure, burr, foreign object biting, thermal deformation, or the like of the injection plunger tip with respect to the injection sleeve.

  As related to the above prior art, in Patent Document 1, as a low-speed injection process, the molten metal supplied into the injection sleeve by driving the electric servo motor is filled up to the runner portion of the mold, and immediately after that, high-speed injection is performed. As the process, the electric servo motor is operated in the same manner as the low-speed injection process, while using the pressure oil stored in the accumulator (ACC), the injection plunger is driven forward at high speed, and the molten metal is placed in the mold cavity. A die casting machine that performs injection filling at a high speed is disclosed, and Patent Documents 2 and 3 disclose the sliding resistance of the injection sleeve for the purpose of detecting an abnormal sliding resistance between the injection sleeve and the injection plunger tip. There is disclosed a die casting machine that detects an abnormality based on hydraulic pressure data during a retraction process of an injection plunger tip.

JP 2006-31505 A JP-A-4-279268 JP-A-3-32460

  However, in the prior art disclosed in Patent Documents 2 and 3, since the sliding resistance when the injection plunger tip is retracted is detected, when the injection plunger tip is moving forward, That is, it is not suitable for accurately detecting an abnormality in sliding resistance when the molten metal is injected and filled. Furthermore, in the injection process of the die casting machine, there are a low-speed injection process and a high-speed injection process in which the injection plunger is advanced at a higher speed and higher pressure than that, and it is based on the pressure of the injection plunger when the high-speed injection process is executed. When the change in the sliding resistance of the injection plunger tip is detected as abnormal, the injection plunger is advanced at high speed and high pressure, so the change at the time of abnormal sliding resistance is small and it is difficult to read the change. It will be a thing. In addition, when a residual body, a burr, or a foreign substance adhering to the inner wall surface of the injection sleeve comes into contact with the injection plunger tip at an acute angle (a state of being caught), the sliding resistance increases. In contrast, when the contact is made obtusely, the sliding resistance becomes small. Therefore, it is possible to accurately detect an abnormality in the sliding resistance when the molten metal is injected and filled into the mold and to mold a good product. Therefore, it is indispensable that the sliding resistance when the injection plunger tip is moved forward, not when it is moved backward is accurately read with high accuracy and the abnormality of the sliding resistance is eliminated at an early stage.

  The present invention has been made in view of the above-described problems. When the injection plunger is advanced and the molten metal is injected and filled, the sliding resistance of the injection plunger with respect to the injection sleeve is detected with high accuracy and high quality. An object of the present invention is to provide a die casting machine capable of obtaining a cast product and a method for detecting an abnormality of the die casting machine.

Invention of da squid strike machine,
A mold cavity having a cylindrical injection sleeve to which a molten metal is supplied and an injection plunger tip provided on an injection plunger that is advanced and retracted in the injection sleeve, and the molten metal is closed by the advance of the injection plunger A die casting machine that uses an electric servo motor as a drive source in a low-speed injection process and uses a hydraulic drive source as a drive source in a high-speed injection process performed in the next process of the low-speed injection process when injecting and filling inside. ,
Torque detection means for detecting the torque of the electric servo motor that advances the injection plunger in a low speed injection process performed at a lower speed than the high speed injection process, and a threshold value in which an actual value detected by the torque detection means is set in advance when a value exceeding, and a failure detecting means for determining as there is abnormality in the forward movement of the injection plunger,
The torque detection means detects the torque of the electric servo motor only during execution of the low-speed injection process .

Invention of the method for detecting abnormality da squid strike machine,
When the molten metal supplied to the cylindrical injection sleeve is injected and filled into the cavity of the mold closed by advancing the injection plunger tip constituted by the injection plunger provided in the injection sleeve. In the low-speed injection process, an electric servo motor is used as the drive source, and in the high-speed injection process performed in the next process of the low-speed injection process, a hydraulic drive source is used as the drive source.
Only during the low-speed injection step, the torque of the electric servo motor is detected by the torque detecting means,
Can the measured values detected by said torque detecting means is a value exceeding the threshold value stored in the pre-Me storage unit, the advancement of the injection plunger tip configured to the injection plunger abnormality detection means on the basis thereof and wherein the determine another to Rukoto as there is an abnormality in the operation.

  According to the present invention, when the die casting machine is in operation, the molten metal remains on the inner wall surface of the injection sleeve and the outer peripheral surface of the injection plunger chip slidably disposed on the inner wall surface of the injection sleeve ( Slipping of the injection plunger tip during the forward movement of the injection plunger tip, or the so-called sag, seizure, burr, foreign object biting, thermal deformation, etc. of the injection plunger tip against the injection sleeve When an abnormality occurs in the resistance, the measured value of the torque of the electric servo motor detected by the torque detection means exceeds the threshold value stored in advance in the storage unit. Then, based on that, the abnormality detection means determines that an abnormality has occurred in the die casting machine. Therefore, based on this determination, the user takes measures to eliminate the abnormality, or when it is determined that there is an abnormality, the control means stops the die casting machine or displays a warning message on the display means. Thus, the user can be alerted. Furthermore, when the abnormality detection means determines that an abnormality has occurred in the sliding resistance of the injection plunger tip, it is executed during the low-speed injection process in which the torque change of the electric servo motor is noticeable. Thus, it is possible to detect accurately, and an abnormality can be detected at an early stage before the change in sliding resistance increases.

It is a perspective view which shows the injection system unit as a principal part of the die-casting machine of this invention. It is explanatory drawing which shows the structure of the injection system unit of a die-casting machine. Part of the operation process in the injection system unit is shown. (A) shows the position of the injection plunger tip on the horizontal axis, the injection speed and the injection pressure on the vertical axis, the solid line is the injection speed, and the one-dot chain line is the injection (B) to (d) show the position of the injection plunger tip on the horizontal axis, the vertical axis of (b) shows the speed of the electric servo motor (only), and the vertical axis of (c) shows the pressure. It shows the torque of the electric servo motor (only), (d) shows the case where an abnormality occurred in the sliding resistance of the injection plunger tip, the solid line shows the torque of the electric servo motor (only), and the alternate long and short dash line Indicates the injection pressure.

  Embodiments of the present invention will be described below with reference to FIGS. Of course, it goes without saying that the present invention can be easily applied to configurations other than those described in the embodiments without departing from the spirit of the invention.

  An injection system unit 1 as a main part configured in the die casting machine shown in FIGS. 1 and 2 includes a machine base 2, a base member 3 mounted on the machine base 2, a fixed die plate 4, and a base member 3. The holding block 5, the support member 6 held on the fixed die plate 4 and the like, the moving body 7 provided so as to be able to move back and forth on the base member 3, and the holding block 5 and the support member 6 are spanned. It is attached to a plurality of guide bars 8 and a holding block 5 for guiding the moving body 7 to advance and retreat, and is held by an electric servo motor 9 and a holding block 5 that are used as a drive source in a low-speed injection process and a pressure increasing process described later. Then, the rotation of the corresponding electric servo motor 9 is screwed with a pair of ball screws 12 and a ball screw 12 that transmit the rotation of the corresponding electric servo motor 9 via a drive transmission mechanism including a pulley 10 and a belt 11. A pair of accumulators (hereinafter referred to as ACCs) as a driving source for a high-speed injection process that is attached to the moving body 7 and is moved to the moving body 7 and is moved along with the moving body 7. 14) An injection plunger 15 that is integrated with the moving body 7 and also serves as a piston body is attached to a hydraulic cylinder 16 and a fixed die plate 4 that can be moved forward and backward by the hydraulic pressure of the ACC 14 that is a hydraulic power source. (Injection plunger tip 15a at the tip of the injection sleeve 18) provided inside the injection sleeve 18 so as to be able to advance and retreat inside, an injection port 18a to which a molten metal provided on the upper portion of the injection sleeve 18 is supplied, the ACC 14 and the first of the hydraulic cylinder 16 The injection plunger 15 is disposed on an oil passage connecting the oil chamber 16a and has a direction switching function and a flow rate control function. The control valve 20 for cutting off the hydraulic pressure supply for advancing at high speed, the cooler 22 disposed on the oil passage connecting the control valve 20 and the tank 21, the tank 21 and the second oil chamber 16 b of the hydraulic cylinder 16 are connected. The hydraulic pump 23 disposed on the oil passage, the first check valve 25 disposed on the oil passage connecting the hydraulic pump 23 and the second oil chamber 16b of the hydraulic cylinder 16, the control valve 20 and the hydraulic cylinder 16 Pressure sensor 26 disposed on an oil passage connecting the first oil chamber 16a, and a second check valve 27 disposed on an oil passage connecting the pressure sensor 26 and the first check valve 25. Control means for controlling the entire die casting machine, which controls the opening and closing of the control valve 20 and the drive of the electric servo motor 9 based on the detection results detected by various sensors and the like, and performs calculation of a threshold value which will be described later. 28, warning messages, etc. Display means 30, and key input means 31 for setting various numerical values (thresholds described later) displayed on the display means 30, and the control means 28 detects the torque of the electric servo motor 9. When the actual value detected by the torque detecting means 32 and the torque detecting means 32 exceeds a preset threshold value, there is an abnormality in the forward movement of the injection plunger 15 (the injection plunger tip 15a of the injection plunger 15). An abnormality detecting means 33 for determining that there is a threshold and a threshold storage unit 34 for storing the threshold in advance are provided.

  In the present embodiment, the rotational force of the electric servo motor 9 is transmitted to the ball screw 12 of the ball screw mechanism via the drive transmission mechanism to rotate the ball screw 12, thereby the nut body of the ball screw mechanism screwed to the ball screw 12. By advancing and retreating 13 in the axial direction, the hydraulic cylinder 16 is moved together with the moving body 7 to advance and retract the injection plunger 15. Further, by supplying the pressure oil accumulated in the ACC 14 to the hydraulic cylinder 16 via the control valve 20, a forward force (pressure increasing pressure) is applied to the injection plunger 15, and the injection plunger (hydraulic cylinder is installed). 15) is advanced, and two electric servo motors 9 and two ball screw mechanisms are provided, and the outputs of the two electric servo motors 9 are added together with the moving body 7 to the hydraulic cylinder 16. Since the provided injection plunger 15 is moved in the axial direction, a relatively large thrust can be obtained.

  Next, the operation of the die casting machine will be described with reference to FIG. In the die casting machine of this embodiment, a low-speed injection process, a high-speed injection process, a pressure-increasing process, a cooling process, a biscuit extrusion process, and a reverse process are sequentially performed as a series of molding processes for manufacturing a molded body. In the present embodiment, first, with the electric servo motor 9 as a drive source, the nut body 13 is advanced together with the moving body 7 via the drive transmission mechanism, the ball screw 12 and the like, and the melt supplied to the injection sleeve 18 from the injection port 18a. The metal material is injected and filled at a low speed from the tip of the injection plunger 15 into the mold cavity closed. In the state before injection, the injection plunger 15 is in the last retracted position, and the control valve 20 is in the neutral position. Therefore, a predetermined amount and a predetermined pressure of pressure oil are stored in the oil chamber of the ACC 14, and at this time, the gas in the gas chamber of the ACC 14 is compressed and boosted by the pressure of the oil. The hydraulic pump 23 is in a stopped state other than the step of feeding oil into the second oil chamber 16b of the hydraulic cylinder 16 including the state before injection. Further, in the state before injection, the nut body 13 is disposed at the most retracted position.

  In such a state, when the start timing of the low-speed injection process is reached, the electric servo motor 9 is moved in a predetermined direction and in the low-speed injection process based on a command from the control means 28 that controls the entire machine. It is rotationally driven at a set speed, whereby the moving body 7, the hydraulic cylinder 16, and the injection plunger 15 together with the nut body 13 of the ball screw mechanism are at a low speed (less than 0.5 m / sec. In this embodiment, Set to 0.25 m / sec.). That is, in the low-speed injection process, the electric servo motor 9 is driven and controlled by speed feedback control along the position axis, whereby the low-speed injection process is executed and the molten metal in the injection sleeve 18 reaches the runner portion of the mold. Filling is performed, and air is evacuated from the cavity of the mold. Then, the control means 28 detects the forward position of the injection plunger 15 based on the output from the position sensor (not shown), and at the timing when the injection plunger 15 is advanced by a predetermined distance set in the low speed injection process, the low speed injection is performed. The process is switched to the high-speed injection process (position (A) in FIG. 3).

  Next, at the start timing of the high-speed injection process, the control means 28 opens the control valve 20 while rotating the electric servo motor 9 in the low-speed injection process, whereby the pressure oil stored in the ACC 14 is The gas pressure that has been compressed and increased is rapidly fed into the first oil chamber (advance oil chamber) 16 a of the hydraulic cylinder 16 through the control valve 20, and the injection plunger 15 is moved toward the moving body 7 at a high speed (0.5 m / min). The speed is at least sec. In this embodiment, the speed is set to 2.5 m / sec.). At that time, the oil in the second oil chamber 16b of the hydraulic cylinder 16 is sent to the first oil chamber 16a of the hydraulic cylinder 16 through the second check valve 27 and the oil passage. In the high-speed injection process, as shown in FIG. 3B, the electric servo motor 9 is rotated at a lower speed than in the low-speed injection process, and the moving body 7 is driven forward at 0.2 m / sec. However, the injection plunger 15 is driven forward at a high speed of 2.5 m / sec by the pressure oil from the ACC 14, whereby the molten metal is rapidly injected and filled into the mold cavity. Then, the control means 28 detects the advance position of the injection plunger 15 based on an output from a position sensor (not shown), and controls the control valve 20 at a timing when the injection plunger 15 is advanced by a predetermined distance set in the high-speed injection process. The hydraulic pressure supply to the first oil chamber 16a of the hydraulic cylinder 16 is shut off to complete the high-speed injection process (position (B) in FIG. 3A).

  When the high-speed injection process is completed, the pressure increasing process is subsequently performed. Upon entering the pressure increasing process, the control means 28 switches the electric servo motor 9 from speed feedback control along the position axis in the injection process (low speed injection process and high speed injection process) to pressure feedback control along the time axis. Then, the electric servo motor 9 is caused to output a pressure that matches the pressure increasing pressure set in the pressure increasing process. By the pressure increasing step, a large pressure (for example, about 50 tons at the maximum) is applied to the metal that has started to solidify in the mold from the injection plunger 15 through the biscuits 29, and the injection plunger is accompanied by the solidification / contraction of the metal. 15 is advanced slightly by a minute amount. And the control means 28 will switch a pressure increase process to a cooling process, if the completion timing of a pressure increase process is detected based on time monitoring.

  Next, in the cooling step, the control means 28 drives and controls the electric servo motor 9 in the forward direction by speed feedback control along the position axis, and advances the moving body 7. As the moving body 7 advances, the injection plunger 15 receives a force in the forward direction. However, since the biscuit 29 contacts the tip of the injection plunger tip 15a of the injection plunger 15, the injection plunger 15 cannot move forward. Retreat against oil pressure. Thereby, the pressure oil in the first oil chamber 16a of the hydraulic cylinder 16 is returned to the oil chamber of the ACC 14 through the control valve 20, and the gas in the gas chamber of the ACC 14 is compressed and boosted accordingly. When the control valve 20 is switched by the control means 28 at a timing when a predetermined amount and a predetermined pressure of pressure oil are stored in the oil chamber of the ACC 14 (pressure oil necessary for the high-speed injection process is stored), The means 28 drives and controls the hydraulic pump 23 so that an amount of oil corresponding to the oil flowing out from the second oil chamber 16b of the hydraulic cylinder 16 in the high-speed injection process is supplied from the hydraulic pump 23 to the second oil chamber of the hydraulic cylinder 16. To 16b. Then, an amount of oil corresponding to the oil flowing out from the second oil chamber 16b of the hydraulic cylinder 16 in the high-speed injection process is sent into the second oil chamber 16b of the hydraulic cylinder 16. Then, at the timing when the injection plunger 15 reaches the last retracted position in the hydraulic cylinder 16, the control means 28 stops the hydraulic pump 23, switches the control valve 20 to the neutral position, and further stops the electric servo motor 9. And wait for the end timing of the cooling process. At this time, the tip of the injection plunger tip 15 a is in contact with the biscuit 29.

  When the cooling process is completed, the control means 28 executes the mold opening process, and in synchronism with this mold opening operation, the electric servo motor 9 is driven and controlled in the forward direction by speed feedback control along the position axis. The moving body 7 is moved forward. And in connection with it, the biscuit extrusion process which extrudes the biscuit 29 by the injection plunger 15 is performed synchronizing with mold opening.

  Next, after the biscuit pushing process is completed, the control means 28 executes a retreating process for retreating the injection plunger 15 at an appropriate timing, and the electric servo motor 9 is moved in the retreating direction by speed feedback control along the position axis. The moving body 7 is moved backward by driving control. And the control means 28 stops the electric servo motor 9 at the timing which the mobile body 7 retracted | retreated to the last retracted position. And many products are manufactured by repeating such a molding cycle.

Here, residual metal (melted residue such as Al) adheres to the inner wall surface of the injection sleeve 18 and the outer peripheral surface of the injection plunger tip 15a slidably disposed on the inner wall surface of the injection sleeve 18. Or when the injection plunger tip 15a is soaked, seized, flashed, entrapped, thermally deformed, etc. with respect to the injection sleeve 18, and the sliding resistance during movement of the injection plunger tip 15a is abnormal. The abnormality detection method will be described with reference to FIG. The entire operation process of the die casting machine according to the present embodiment is as described above. However, in the die casting machine according to the present embodiment, the abnormal detection of the sliding resistance of the injection plunger tip 15a with respect to the injection sleeve 18 is detected. Do it when running.

  As shown in the graphs of FIGS. 3A to 3C, the torque of the electric servo motor 9 is stable without being disturbed in a state where no abnormality has occurred in the sliding resistance of the injection plunger tip 15a. (See FIG. 3C), when the above-described abnormality of the sliding resistance occurs, the torque of the electric servo motor 9 and the injection pressure graph are displayed in the high-speed injection process as shown on the right side of FIG. In the low-speed injection process using only the electric servo motor 9 that is executed at a lower speed and lower pressure than the high-speed injection process, although the disturbance does not occur, as shown on the left side of FIG. It appears prominently in the graph as turbulence (continuous mountain folds and valley folds). Then, as shown in (e) and (f), as shown in the measurement section in the low-speed injection process, the torque based on the torque values X and Y of the electric servomotor 9 corresponding to the preset measurement section is normal. The values X ′ and Y ′ that are 10% higher than the values are calculated, and the values are stored in the threshold value storage unit 34 in advance as threshold values, so that the torque detection means 32 can detect them during the operation of the die casting machine. When the actually measured value of the torque of the electric servo motor 9 is a value exceeding the threshold value, the abnormality detection means 33 determines that the forward movement of the injection plunger 15 is abnormal, and based on this determination, the control means 28 The operation of the die casting machine is stopped and a warning message is displayed on the display means 30.

  As described above, according to the die casting machine of the present embodiment, the cylindrical injection sleeve 18 to which the molten metal is supplied, and the injection plunger tip 15a attached to the tip of the injection plunger 15 that is advanced and retracted in the injection sleeve 18 are provided. When the molten metal is injected and filled in the cavity of the mold that is closed by the advancement of the injection plunger 15, only the electric servo motor 9 is used as the drive source in the low-speed injection process. In the high-speed injection process performed in the process, the die casting machine uses the hydraulic drive source ACC14 and the electric servo motor 9 as its drive sources, and the electric plunger 15 moves forward in the low-speed injection process performed at a lower speed than the high-speed injection process. Torque detection means 32 for detecting the torque of the servo motor 9 and actual values detected by the torque detection means 32 are preset. When the value exceeds the threshold value, an abnormality detecting means 33 for determining that there is an abnormality in the forward movement of the injection plunger 15 is provided, whereby the injection sleeve 18 is operated when the die casting machine is operating. A residual metal melt (a molten metal such as Al) adheres to the outer peripheral surface of the injection plunger tip 15a slidably disposed on the inner wall surface of the injection sleeve 18 or the injection sleeve 18, or the injection sleeve When the injection plunger tip 15a is subjected to so-called sag, seizure, burr, foreign object biting, thermal deformation, etc., and the sliding resistance during the forward movement of the injection plunger tip 15a is abnormal, it is detected by the torque detecting means 32. Since the actual measured value of the torque of the electric servo motor 9 exceeds the threshold value stored in the threshold value storage unit 34 in advance, the abnormality detection method 33 it is determined that an abnormality has occurred in the sliding resistance of the injection plunger tip 15a of the die casting machine. Therefore, based on this determination, the user takes measures (maintenance or the like) for eliminating the abnormality, or when it is determined that there is an abnormality, the control means 28 stops the die casting machine, or the display means 30. By displaying a warning message on the screen, the user can be alerted. Furthermore, when the abnormality detection means 33 determines that an abnormality has occurred in the sliding resistance of the injection plunger tip 15a, the abnormality detection means 33 is executed during the low-speed injection process in which the torque change of the electric servo motor 9 appears significantly. Can be detected accurately with high accuracy, and before the change in sliding resistance becomes large, it becomes possible to detect abnormalities at an early stage and to manufacture a cast product with good quality.

  As mentioned above, although an example of this embodiment was explained in full detail, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. In the above example, the threshold value is increased by 10% with respect to the torque value of the electric servomotor 9 when there is no abnormality in the sliding resistance. However, the threshold value is not limited to this, and is suitably in the range of 1% to 40%. It is also possible to select. Further, when the abnormality detection means 33 determines that the sliding resistance is abnormal, the operation of the die casting machine may be stopped or a warning message may be displayed on the display means 30. Also, the abnormality detection means 33 determines how much the actual measurement value of the electric servo motor 9 has increased with respect to the threshold value, and “low”, “medium” and “large” indicate warning levels corresponding to the increase value. The importance level may be changed and displayed on the display unit 30. In addition, the abnormality detection unit 33 has been described as determining that there is an abnormality in the sliding resistance when the actual measurement value of the electric servo motor 9 exceeds the threshold value. However, the average value or peak of the actual measurement value in the measurement section has the threshold value. Based on the value when exceeding, you may make it discriminate | determine that there is abnormality in the sliding resistance of the injection | pouring plunger tip 15a. Further, the sliding resistance abnormality may be detected not only when the injection plunger 15 is moved forward but also when the injection plunger 15 is moving backward.

DESCRIPTION OF SYMBOLS 1 Injection system unit 2 Machine stand 3 Base member 4 Fixed die plate 5 Holding block 6 Support member 7 Moving body 8 Guide bar 9 Electric servo motor 10 Pulley 11 Belt 12 Ball screw 13 Nut body 14 ACC (hydraulic drive source)
15 injection plunger 15a injection plunger tip 16 hydraulic cylinder 16a first oil chamber 16b second oil chamber 18 injection sleeve 18a inlet 20 control valve 21 tank 22 cooler 23 hydraulic pump 25 first check valve 26 pressure sensor 27 second sensor Check valve 28 Control means 29 Biscuit 30 Display means 31 Key input means 32 Torque detection means 33 Abnormality detection means 34 Storage part (threshold value storage part)

Claims (2)

A mold cavity having a cylindrical injection sleeve to which a molten metal is supplied and an injection plunger tip provided on an injection plunger that is advanced and retracted in the injection sleeve, and the molten metal is closed by the advance of the injection plunger A die casting machine that uses an electric servo motor as a drive source in a low-speed injection process and uses a hydraulic drive source as a drive source in a high-speed injection process performed in the next process of the low-speed injection process when injecting and filling inside. ,
Torque detection means for detecting the torque of the electric servo motor that advances the injection plunger in a low speed injection process performed at a lower speed than the high speed injection process, and a threshold value in which an actual value detected by the torque detection means is set in advance when a value exceeding, and a failure detecting means for determining as there is abnormality in the forward movement of the injection plunger,
The die-casting machine characterized in that the torque detection means detects the torque of the electric servo motor only during the low-speed injection process . When the molten metal supplied to the cylindrical injection sleeve is injected and filled into the cavity of the mold closed by advancing the injection plunger tip constituted by the injection plunger provided in the injection sleeve. In the low-speed injection process, an electric servo motor is used as the drive source, and in the high-speed injection process performed in the next process of the low-speed injection process, a hydraulic drive source is used as the drive source.
Only during the low-speed injection step, the torque of the electric servo motor is detected by the torque detecting means,
Can the measured values detected by said torque detecting means is a value exceeding the threshold value stored in the pre-Me storage unit, the advancement of the injection plunger tip configured to the injection plunger abnormality detection means on the basis thereof abnormality detection method of the die casting machine, characterized in determine specific to Rukoto as there is abnormality in the operation.

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