How to set up the casting machine

Abstract

To provide an initialization method for a die cast machine, which enables an injection filling operation to be performed at a high-accuracy injection speed and casting pressure from a first shot of cast forming, and which enables quality of a casting to be stabilized by a stable operation of the die cast machine.SOLUTION: An initialization method for a die cast machine of the present invention includes a normal operation mode and an initialization mode. In the initialization mode, correlation data on a detection signal of a position detection part and a travel speed of a forward / backward travel operation of a plunger is created; correction processing of control data preset in an injection control part is performed on the basis of the correlation data; and subsequently, the normal operation mode is enabled.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for initializing a die-casting machine that produces a casting by injecting molten metal into a die cavity. [Background technology]

[0002] In die-casting machines, molten metal such as aluminum alloy is supplied into the injection sleeve, and the plunger is advanced to inject and fill the mold cavity. Next, a holding pressure is applied to the molten metal in the mold cavity to compensate for the solidification shrinkage of the molten metal as it cools and solidifies. After the molten metal cools and solidifies in the mold cavity, it is removed from the mold cavity as a cast. At the same time, the plunger is retracted to supply molten metal back into the injection sleeve, and the process moves on to the preparation step for the next casting. This series of casting processes is repeated until the planned number of cast products is obtained.

[0003] The injection and packing of the molten metal into the mold cavity and the pressure holding process are the most important molding processes that significantly affect the quality of the casting. For example, if the forward movement of the plunger (called the injection speed) during the injection and packing process is unstable, the molten metal in the injection sleeve will ripple and become violent, resulting in casting defects caused by the injection speed, such as air entrapment (void defects), poor molten metal wrinkles, poor molten metal flow, and the inclusion of molten metal oxides (foreign matter). Furthermore, if the pressure applied to the molten metal inside the injection sleeve and mold cavity during the pressure holding process (both called the casting pressure) is unstable, casting defects caused by the casting pressure, such as casting burrs, poor molten metal flow, sink marks, poor transfer, and casting defects, will occur.

[0004] To achieve this, a die-casting machine that can control the injection speed and casting pressure with high precision is required. For example, Patent Document 1 proposes a die-casting machine equipped with an injection unit that uses a spool-type control valve driven by a servomotor via a ball screw to control the hydraulic flow rate to the injection cylinder. Utilizing the highly accurate rotation control of the servomotor, highly accurate hydraulic flow rate control is achieved, enabling highly accurate control of the injection speed and casting pressure, resulting in stable casting quality.

[0005] Furthermore, Patent Document 2 proposes an injection control method for a die casting machine with a hydraulically driven injection unit equipped with a servo valve, in which initial command data, including mold characteristics, is created based on injection position feedback, and an appropriate injection speed and automatic adjustment are performed based on this data. Target speed data for the injection filling operation is set in advance, and the command data and measured speed data are recorded during the actual injection filling operation. A correction value is calculated by comparing the target speed data with the measured speed data, and the command data is corrected using this correction value. The corrected command data is then used to perform the next injection filling operation. By performing the injection filling operation using the latest corrected command data in this way, it is claimed that stable casting quality can be achieved. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-58114 [Patent Document 2] JP 2001-314954 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the method disclosed in Patent Document 1 does not take into consideration changes or errors in the control accuracy of injection speed and casting pressure due to changes in the operating environment. For example, the viscosity of hydraulic oil changes with temperature changes, and the operating state of the hydraulic oil, which affects the control accuracy of injection speed and casting pressure, also changes. In addition, hydraulic oil deteriorates with the length of use, and the operating state of the hydraulic oil also changes in the same way as temperature changes. Furthermore, mechanical parts such as servo motors, ball screws, and spools inevitably change over time with the length of use, and the operating state of these mechanical parts, which strongly affects the control accuracy of injection speed and casting pressure, also changes.

[0008] In contrast, the method described in Patent Document 2 is said to be able to eliminate changes and errors in the control accuracy of injection speed and casting pressure due to changes in the operating environment, such as changes in oil temperature and aging, through correction processing. However, the measurement data used as the basis for calculating the correction amount is measured during injection and filling operations in an unadjusted state, so there remains the issue that the calculated correction amount itself is not very reliable. Furthermore, even if a highly accurate correction result is ultimately obtained by repeated correction, there remains the issue that the number of shots required to reach the final result may contain casting defects.

[0009] Therefore, an object of the present invention is to provide an initial setting method for a die casting machine that can perform injection filling operations with highly accurate injection speed and casting pressure from the first shot of casting, thereby achieving stable operation of the die casting machine and stabilizing the quality of the cast product. [Means for solving the problem]

[0010] The initial setting method for a die-casting machine of the present invention is a die-casting machine in which molten metal is supplied inside an injection sleeve and the molten metal is injected and filled into a mold cavity by the forward and backward movement of a plunger, and the die-casting machine is equipped with an injection cylinder that moves the plunger forward and backward, a servo valve that adjusts the amount of hydraulic pressure supplied to the injection cylinder, and an injection control unit that controls the servo valve to control the forward and backward movement of the plunger. The servo valve includes a servo motor, a ball screw mechanism that converts the rotational motion of the servo motor into linear motion, a spool that is connected to the ball screw mechanism and adjusts the hydraulic flow rate by forward and backward motion, and a position detection unit that detects the position of the spool. The injection control section has a normal operation mode and an initial setting mode. The initial setting mode is characterized by creating correlation data between the detection signal of the position detection unit and the movement speed of the plunger's forward and backward movement, correcting the control data preset in the injection control unit based on the correlation data, and then enabling the normal operation mode.

[0011] In the method for initializing a die casting machine of the present invention, it is preferable that the position detection unit be substituted by an encoder that detects the rotational movement of a servo motor.

[0012] In the method for initializing a die casting machine of the present invention, it is preferable that the correlation data is collected within a range from the measurement start point to the measurement end point set at the spool position.

[0013] In the initial setting method for a die casting machine of the present invention, it is preferable that the correction process sets the control data as the control command value for the normal operation mode when the difference between the correlation data and the control data falls within a predetermined allowable range value.

[0014] Furthermore, in the initial setting method for a die-casting machine of the present invention, if the difference between the correlation data and the control data exceeds a preset tolerance range, the correction process preferably corrects the control data so that it falls within the tolerance range, creates new corrected control data, and sets the corrected control data as the control command value for the normal operation mode.

[0015] Furthermore, in the initial setting method for a die casting machine of the present invention, it is preferable that the correction process uses the correlation data as a control command value for the normal operation mode. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an initial setting method for a die casting machine that can perform injection filling operations with highly accurate injection speed and casting pressure from the first shot of casting, thereby achieving stable operation of the die casting machine and stabilizing the quality of the cast product. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a conceptual diagram of an injection device of a die casting machine according to an embodiment. [Figure 2] FIG. 2 is a detailed view of the hydraulic drive unit and servo valve of FIG. 1. [Figure 3] FIG. 2 is a detailed view of the injection control unit in FIG. 1. [Figure 4] FIG. 1 is a flow diagram of an initial setting method according to an embodiment. [Figure 5] 5 shows an example of the initial setting method in FIG. 4, where (a) is a waveform showing the spool position and plunger movement speed from the measurement start point to the measurement end point, (b) is a waveform in which the control data and the allowable range value are overwritten, and (c) is a waveform in which the correction data are overwritten. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments for carrying out the present invention will be described below with reference to the drawings. Note that the following embodiments do not limit the inventions according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solutions of the inventions according to the claims. Furthermore, in the present embodiments, the scales and dimensions of each component may be exaggerated, and some components may be omitted.

[0019] [Die casting machine] First, the die-casting machine according to this embodiment will be described with reference to Fig. 1. In the following description, the die-casting machine according to this embodiment will be based on a horizontal die-casting machine, but the present invention is not limited to this.

[0020] The die-casting machine 100 shown in Fig. 1 includes a fixed mold 1 supported by a fixed platen (not shown), a movable mold 3 supported by a movable platen (not shown) and movable toward and away from the fixed platen 1, an injection device 10 that injects molten metal, and an injection control unit 40 that controls the operation of the injection device 10. A casting is formed by injecting and filling molten metal such as an aluminum alloy into a mold cavity 5 formed by the fixed mold 1 and the movable mold 3 using the injection device 10.

[0021] The injection device 10 includes an injection sleeve 11 into which molten metal is supplied, a plunger 13 that can move forward and backward inside the injection sleeve 11, a plunger rod 15 connected to the plunger 13, a hydraulic drive unit 20 that is connected to the plunger rod 15 and moves the plunger 13 forward and backward, and a servo valve 30 that controls the hydraulic drive unit 20 in accordance with a control command value from an injection control unit 40. Regarding the movement of the plunger 13, the movement toward the mold cavity 5 is defined as an advance movement, and the movement away from the mold cavity 5 is defined as a retreat movement. The position at which the plunger 13 completes its retreat movement is defined as a standby position GE, and the position at which the plunger 13 completes its advance movement is defined as an injection completion position ZE. In other words, the plunger 13 moves forward and backward within the range between the standby position GE and the injection completion position ZE. The hydraulic drive unit 20 is also provided with a position sensor 21 that detects the position of the plunger 13.

[0022] The injection sleeve 11 is a cylindrical body supported horizontally in a state where it protrudes rearward from a fixed platen (not shown). The axial direction of the injection sleeve 11 corresponds to the forward and backward movement of the plunger 13. The front side of the injection sleeve 11 penetrates the fixed platen so as to communicate with the mold cavity 5, and is fastened to a predetermined position on the fixed mold 1. A pouring port 17 is provided on the rear side of the injection sleeve 11. When the plunger 13 is waiting at the waiting position GE, molten metal is supplied into the injection sleeve 11 through the pouring port 17 from a melt supply device (not shown) or the like. Furthermore, a cooling mechanism (not shown) including a flow path for a cooling medium such as cooling water is provided as needed for the injection sleeve 11 and the plunger 13. Furthermore, it is preferable to apply a lubricant to the sliding surfaces of the injection sleeve 11 and the plunger 13 in order to prevent wear and damage to the plunger 13, stabilize the sliding state, and suppress adhesion of molten metal residue.

[0023] Next, the hydraulic drive unit 20 and the servo valve 30 will be described with reference to Fig. 2. Note that Fig. 2 is simplified to the extent that this embodiment can be explained. The hydraulic drive unit 20 comprises an injection cylinder 22 and an accumulator 28. The piston rod 27 of the injection cylinder 22 is connected to the plunger 13 via the plunger rod 15. The head-side hydraulic chamber 23 on the piston head 26 side of the injection cylinder 22 is connected to the accumulator 28 via hydraulic piping. Hydraulic pressure supplied from the accumulator 28 pushes the piston head 26, causing the plunger 13 to move forward via the piston rod 27. Alternatively, the hydraulic drive unit 20 adjusts the pressing force of the plunger 13. The forward movement of the piston rod 27 is referred to as the forward movement of the injection cylinder 22, and the forward speed of the piston rod 27 is referred to as the injection speed of the injection cylinder 22. The pressing force of the plunger 13 is referred to as the casting pressure of the injection cylinder 22. Here, matching the forward and backward movement directions of the injection cylinder 22 and the plunger 13 facilitates initial setup of the die-casting machine 100, which will be described later. The gas bottle 29 is used to supply pressurized gas to the accumulator 28.

[0024] The servo valve 30 is composed of a valve body 31, a servo motor 33, and a ball screw mechanism 35. A slidable spool 313 is incorporated inside the valve body 31, and the forward and backward movement of the injection cylinder 22 can be controlled by changing the position of this spool 313. Specifically, the rod-side hydraulic chamber 25 on the piston rod 27 side of the injection cylinder 22 is connected to a hydraulic port 315 of the valve body 31 by hydraulic piping, and the injection cylinder 22 moves forward by controlling the amount of hydraulic pressure discharged from the rod-side hydraulic chamber 25 through control of the position of the spool 313 (this is called a meter-out control system). As a result, the forward movement of the plunger 13 connected to the plunger rod 27 of the injection cylinder 22 is controlled. Here, by aligning the directions of the forward and backward movements of the spool 313 and the injection cylinder 22, it is possible to align the directions of the forward and backward movements of the plunger 13, the injection cylinder 22, and the spool 313, and by precisely controlling the forward and backward movement of the spool 313, it is possible to control the injection speed and the casting pressure with high precision. In explaining this embodiment, the forward movement of the spool 313 is defined as the + direction, and the backward movement of the spool 313 is defined as the - direction.

[0025] The rotation state of the servo valve 33 is detected by an encoder 37 and sent to an injection control unit 40. The injection control unit 40 receives the detection signal from the encoder 37 and performs feedback control of the rotational movement of the servo motor 33 so that there is no error with the preset control data. The feedback-controlled rotational movement of the servo motor 33 is converted into linear movement by a ball screw mechanism 35, and the forward and backward movement of the spool 313 is controlled via a connecting rod 312.

[0026] Here, we will explain how highly accurate feedback control can be achieved using typical mechanical specifications for the servo motor 33 and encoder 37. The rotation of the servo motor 33 results in forward and backward movement of the spool 313, which is connected to the connecting rod 312 via the ball screw mechanism 35. Assume, for example, that one rotation of the servo motor 33 causes the spool 313 to move 25 mm. Also, assume that an encoder 37 that emits 20,000 pulses is used. As a result, 10 pulses of the detection signal from the encoder 37 are detected as a movement of 0.0125 mm of the spool 313. In reality, the rotation of the servo motor 33 is controlled by the single-digit number of detected pulses from the encoder 37. This principle allows for highly accurate rotation control of the servo motor 33, which ultimately enables the position of the spool 313 to be controlled with a high degree of precision on the order of 0.01 mm, thereby enabling highly accurate forward and backward movement of the plunger 13.

[0027] [Default setting mode] Next, the initial setting mode for initializing the die casting machine according to this embodiment will be described with reference to FIG. 3 . The injection control unit 40 shown in FIG. 3 has a normal operation mode 41 and an initial setting mode 43. When the die casting machine 100 is started, the initial setting mode 43 is enabled and the normal operation mode 41 is disabled. Therefore, the initial setting mode 43 is first initiated to initialize the die casting machine 100, and the normal operation mode 41 is enabled only after the initial setting. In other words, by initializing the die casting machine 100 using the initial setting mode 43 before starting casting, changes and errors in the control accuracy of the injection speed and casting pressure of the die casting machine 100 due to changes in the operating environment can be accurately corrected. As a result, casting defects due to malfunctions during casting and machine damage due to injection runaway can be reliably prevented. It is preferable to perform quality assessments of the control devices and mechanical components related to the control of the injection speed and casting pressure before starting the initial setting mode 43.

[0028] The initial setting mode 43 includes an input / output unit 431 that transmits and receives detection signals from the encoder 37 and control data for the servo motor 33, a condition setting unit 433 that sets conditions for the rotational operation of the servo motor 33, a control unit 435 that controls the rotational operation of the servo motor 33 based on the settings of the condition setting unit 433, a processing unit 437 that performs processing such as correction and conversion of the control data based on the detection signals from the encoder 37, a memory unit 438 that stores the processing results of the processing unit 437, and an alarm issuing unit 439 that issues an alarm if an abnormality is detected based on the processing results of the processing unit 437. If the processing result of the processing unit 437 is normal, the initial setting mode 43 ends, the normal operation mode 41 is enabled, and casting begins. The memory unit 438 is connected to the normal operation mode 41.

[0029] Here, the condition setting unit 433 sets a rotation direction setting value that determines the rotation direction of the servo motor 33, a rotation speed setting value that determines the rotation speed, a rotation torque setting value that determines the rotation torque, and a measurement start point S and a measurement end point E that determine the rotation range in the initial setting mode 43. These setting values are used to perform initial setting of the die casting machine.

[0030] [Initial Setup Method] Next, a method for initializing the die casting machine using the initial setting mode according to this embodiment will be described with reference to Figures 4 and 5. When the die casting machine 100 is started up, the initial setting mode 43 is enabled and the normal operation mode 41 is disabled. Therefore, the initial setting mode 43 must always be used first to perform initial settings for the die casting machine 100.

[0031] When the initial setting mode 43 is started, as shown in FIG. 4, the servo motor 33 rotates from the measurement start point S to the measurement end point E based on the setting value entered in the condition setting unit 433. Here, the measurement start point S and the measurement end point E are set by the position of the spool 313 of the servo valve 30. These settings are set within the range of the mechanical forward and backward limits of the spool 313. In other words, they are set to match the range of the injection speed and casting pressure used as molding conditions in the casting process performed after the initial setting mode 43. This allows for focused improvement in the control accuracy of the injection speed and casting pressure in accordance with the casting conditions, thereby ensuring stable casting quality. For example, moving the spool 313 forward in the positive direction from the measurement start point S to the measurement end point E reproduces the injection filling operation.

[0032] Here, the position of the spool 313 is measured using a position detection unit 39 provided in the valve body 31. The position detection unit 39 may be a commercially available contact type displacement sensor such as an eddy current loss type displacement sensor or a contact type displacement sensor, or a non-contact type displacement sensor such as a laser displacement sensor. Furthermore, the detection signal of the encoder 37, which detects the rotational movement of the servo motor 33 connected to the spool 313 via the ball screw mechanism 35, may be used as a substitute for the position detection unit 39 of the spool 313. In this case, as described above, the servo motor 33 and the encoder 37 have very high resolution, and the ball screw mechanism 35 also has high conversion accuracy, so that highly accurate position measurement is possible, making this an ideal substitute for the position detection unit of the spool 313. It is preferable to clarify in advance the relationship between the detected value of the encoder 37 for one rotation of the servo motor 33 and the movement distance of the spool 313. As a result, the rotation control of the servo motor 33 and the position detection of the spool 313 are performed simultaneously based on the detection signal of the encoder 37, thereby improving both the position control of the spool 313 and the measurement accuracy.

[0033] Returning to the explanation of Fig. 4, when the position of the spool 313 detected by the encoder 37 reaches the measurement end point E, the rotation of the servo motor 33 is stopped, and the measurement data collected by the input / output unit 431 is edited by the processing unit 437, and the edit processing result is stored in the storage unit 438. Here, the measurement data refers to the measured values of the position of the spool 313 and the movement speed of the plunger 13 in the range from the measurement start point S to the measurement end point E. The editing process involves creating correlation data DS of the movement speed of the plunger 13 corresponding to the position of the spool 313, as shown in FIG. 5. FIG. 5 also shows the correlation data DS obtained when the spool 313 is advanced in the positive direction from the measurement start point S to the measurement end point E, and the movement speed of the plunger 13 during the forward movement indicates the injection speed. Although not shown, the correlation data DS obtained when the spool 313 is advanced in the negative direction from the measurement start point S to the measurement end point E indicates the retraction speed of the retracting plunger 13. FIG. 5 is merely an approximation to the extent that it can be understood to explain this embodiment.

[0034] The movement speed of the plunger 13 is calculated from the movement amount of the plunger 13 and the elapsed time. The movement amount of the plunger 13 is measured, for example, by a position sensor 21 attached to the hydraulic drive unit 20, as shown in FIG. 1 or FIG. 2, by measuring the movement amount of the piston head 26 or the piston rod 27 of the injection cylinder 22. Note that in FIG. 1 or FIG. 2, the position sensor 21 is attached to the hydraulic drive unit 20, but this is not limited thereto. For example, a position sensor may be attached to the plunger rod 15 to directly measure the movement amount of the plunger rod 15. Note that there are restrictions on attaching a position sensor to the plunger tip 13 due to the temperature rise caused by the high-temperature molten metal and the fact that the plunger tip 13 slides within the injection sleeve 11. Furthermore, the position sensor 21 may be a commercially available contact-type displacement sensor, such as an eddy current loss type displacement sensor or a contact-type displacement sensor, or a non-contact-type displacement sensor, such as a laser displacement sensor.

[0035] Here, the explanation of the initial setting method for the die casting machine 100 using the initial setting mode 34 will focus on the injection speed and casting pressure of the injection filling process, which have the greatest impact on casting quality. That is, as shown in Figure 5, the explanation will be made on the initial setting method using correlation data DS of the moving speed (injection speed) in the forward direction of the plunger 13, which has been edited based on the measurement data obtained by moving the spool 313 forward in the positive direction from the measurement start point S to the measurement end point E. As for the initial setting methods using other correlation data, the only differences are the selection conditions, such as whether to change the moving direction or range of the spool 313, or whether to use the casting pressure instead of the injection speed, and therefore the procedures are the same, and therefore explanations will be omitted.

[0036] As shown in FIG. 5(a), within the range of the spool 313 from the measurement start point S to the measurement end point E, correlation data DS of the position of the spool 313 and the moving speed (injection speed) of the forward movement of the plunger 13 is edited by the processing unit 437. After the editing process, as shown in FIG. 4, the processing unit 437 compares the correlation data DS with control data DC pre-registered in the injection control unit 40. Here, the control data DC is control data that is initially set as machine specification values when the die casting machine 100 is designed and manufactured. By comparing the control data DC with the correlation data DS, it is possible to quantify the degree of change and error in the control accuracy of the injection speed and casting pressure due to changes in the operating environment, etc.

[0037] If the comparison judgment by processing unit 437 determines that the correlation data DS and the control data DC match (DS=DC), it is determined that there is no change or error in control accuracy, and that stable production of high-quality cast products can be ensured even if casting is performed using the control data DC registered in injection control unit 40. After this judgment, initial setting mode 43 ends and normal operation mode 41 is enabled. In normal operation mode 41, casting is started using the control data DC.

[0038] If the comparison by the processing unit 437 finds that the correlation data DS and the control data DC do not match (DS≠DC), the processing unit 437 performs an acceptability determination using an allowable range value K of the control data DC pre-registered in the injection control unit 40. The allowable range value K is calculated based on, for example, actual measurements of changes and errors in the control accuracy of the injection speed and casting pressure, determined from past casting results, and the allowable range of the casting quality at that time. Note that a value obtained by multiplying the calculated result by a safety factor may be set. Alternatively, the value may be set based on design reference values at the time of designing the die-casting machine 100 or actual values such as the machining accuracy of machine parts during manufacturing. The acceptability determination is performed by adding the allowable range value K to the correlation data DS to determine the allowable range DS±K of the correlation data DS, and determining whether the control data DC falls within this allowable range.

[0039] Here, as shown in Figure 5(b), if it is determined that the control data DC is within the allowable range DS±K (indicated by the dashed line in the figure) (DC≦DS±K), it is determined to be normal, meaning that it is possible to obtain casting quality equivalent to that of past castings. After this normal determination, the initial setting mode 43 is terminated and the normal operation mode 41 is enabled. In this case, casting is also started in the normal operation mode 41 using the control data DC.

[0040] As shown in FIG. 5(c), if it is determined that the control data DC is outside the allowable range DS±K (indicated by the dashed line in the figure) (DC>DS±K), the process proceeds to step 1 or step 2 as shown in FIG. 4.

[0041] First, step 1 will be described. In step 1, the control data DC registered in the injection control unit 40 is corrected so that it falls within the allowable range DS±K. Specifically, the control gain, etc. of the injection control unit 40 is adjusted to create corrected control data DCH, and measurement data is re-acquired within the range from the control start point S to the control end point E based on this control data DCH. Next, the comparison judgment and allowance judgment described above are performed. This correction, comparison judgment, and allowance judgment are repeated until the data falls within the allowable range DS±K. Finally, the corrected control data DCH, which falls within the allowable range DS±K (DCH≦DS±K), is stored in the memory unit 438 as corrected control data DH, as shown in FIG. 5(c). Thereafter, the initial setting mode 43 is terminated, the normal operation mode 41 is enabled, and casting begins. Here, the memory unit 438 is connected to the normal operation mode 41, and the normal operation mode 41 performs casting using the corrected control data DH stored in the memory unit 438. In other words, even if changes or errors occur in the control accuracy of the injection speed or casting pressure due to changes in the operating environment, etc., the initial setting method shown in step 1 corrects the control data to the latest state, thereby ensuring stable production of high-quality cast products from the first shot of casting.

[0042] Next, we will explain step 2. For example, in situations where it is necessary to start casting as soon as possible due to production planning or the like, or in situations where it is difficult to repeatedly make corrections and redoes as in step 1, we propose an initial setting method for step 2. In step 2, as shown in Fig. 5(c), the control data DC registered in the injection control unit and the correlation data DS stored in the memory unit 438 are exchanged and converted. After the conversion, the initial setting mode 43 is ended, the normal molding mode 41 is enabled, and casting is started. In the normal molding mode 41, casting is performed using the correlation data DS stored in the memory unit 438. As with the initial setting method of step 1, this initial setting method of step 2 ensures stable production of high-quality cast products from the first shot of casting by correcting the control data to the latest state, even if changes or errors occur in the control accuracy of the injection speed or casting pressure due to changes in the operating environment, etc. Furthermore, it simplifies the initial setting process and can also achieve the effect of improving productivity by shortening the time from starting up the die-casting machine 100 to starting casting.

[0043] In this way, before the actual casting operation, the initial setting mode 43 is used to initialize the servo motor 33, encoder 37, ball screw mechanism 35, spool 313 of the servo valve 30, hydraulic drive unit 20, and control circuit related to the injection filling of the plunger 13. This makes it possible to quantify the degree of error and change in control accuracy of the injection filling operation due to changes in the operating environment, etc. Furthermore, by adding correction and conversion processing of the control data, it is possible to correct changes in control accuracy and error, reset changes in the state of the die casting machine due to changes in the operating environment, aging, etc., and ensure stable casting operations of the die casting machine.

[0044] Although the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above-described embodiments. Various modifications and improvements can be made to the above-described embodiments. [Explanation of symbols]

[0045] 1 Fixed mold 3 Movable mold 5 Mold Cavity 10 Injection device 11 Injection sleeve 13 Plunger 15 Plunger rod 17 Pouring spout 20 Hydraulic drive unit 21 Position Sensor 22 Injection cylinder 30 Servo valve 313 Spool 312 Connecting rod 33 Servo motor 35 Ball screw mechanism 37 Encoder 40 Injection control unit 41 Normal operation mode 43 Initial setting mode 100 die casting machines S Measurement starting point E Measurement end point DS Correlation Data DC Control Data DH correction control data

Claims

1. A die casting machine in which molten metal is supplied into an injection sleeve and the molten metal is injected and filled into a mold cavity by the forward and backward movement of a plunger, an injection cylinder that moves the plunger forward and backward; a servo valve that adjusts the amount of hydraulic pressure supplied to the injection cylinder; and an injection control unit that controls the servo valve to control the forward and backward movement of the plunger, The servo valve includes a servo motor, a ball screw mechanism that converts rotational motion of the servo motor into linear motion, a spool that is connected to the ball screw mechanism and adjusts the flow rate of hydraulic pressure by forward and backward motion, and a position detection unit that detects the position of the spool, The injection control unit has a normal operation mode and an initial setting mode, When the die casting machine is started, the initial setting mode is enabled and the normal operation mode is disabled, the initial setting mode creates correlation data between the detection signal of the position detection unit and the moving speed of the forward and backward movement of the plunger, corrects control data preset in the injection control unit based on the correlation data, and then enables the normal operation mode; The correction process includes: When the difference between the correlation data and the control data is within a preset allowable range, the control data is set as a control command value for the normal operation mode, and when a difference between the correlation data and the control data exceeds a preset tolerance, correcting the control data so that the difference falls within the tolerance to create new corrected control data, and setting the corrected control data as a control command value for the normal operation mode.

2. 2. The method for initializing a die casting machine according to claim 1, wherein the position detection unit is substituted by an encoder that detects the rotational movement of the servo motor.

3. 3. The method for initializing a die casting machine according to claim 1, wherein the correlation data is collected within a range from a measurement start point to a measurement end point set at the spool position.

Images