Casting molding device and casting manufacturing method

Abstract

To perform evaluation of a quality of a casting, with high accuracy, and simplify work for eliminating a cause of influencing the quality.SOLUTION: A casting molding device, which is provided with a fixed die, a movable die and a cavity formed by the fixed die and the movable die and obtains a casting through an injecting step of injecting molten metal into the cavity, is further provided with an injection control part that controls injection speed of the molten metal and a speed analyzing part that analyzes the injection speed in the injecting step. In the injection step, a low-speed area where the injection speed is controlled to follow up a set value and a high-speed area where the injection speed follows up a set value larger than the set value in the low-speed area are set. The speed analyzing part determines maximum values and minimum values of the injection speed, in each of a plurality of divided areas obtained by diving the low-speed area arbitrarily.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present disclosure relates to a casting molding apparatus and a method for producing a casting. [Background technology]

[0002] Patent Document 1 discloses a die-casting machine that has a fixed mold and a movable mold, and that forms a casting product by injecting molten metal into a cavity formed by the fixed mold and the movable mold using the extrusion force of a plunger that slides inside a sleeve. After the molten metal fills the cavity, the control device included in this die-casting machine predicts the occurrence of defects in the casting product based on the rise time of the pressure that the plunger applies to the molten metal and the stable value of the pressure. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-157641 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a casting molding apparatus and a casting manufacturing method that can perform high-precision quality evaluation of castings and simplify the work of eliminating factors that affect quality. [Means for solving the problem]

[0005] [1] A casting molding apparatus having a fixed mold, a movable mold, and a cavity formed by the fixed mold and the movable mold, which obtains a cast product through an injection process in which molten metal is injected into the cavity, the casting molding apparatus comprising: an injection control unit which controls the injection speed of the molten metal in the injection process; and a speed analysis unit which analyzes the injection speed in the injection process, wherein the injection process has a low speed region in which the injection speed is controlled to follow a set value, and a high speed region in which the injection speed is controlled to follow a set value that is greater than the set value in the low speed region, and the speed analysis unit determines the maximum and minimum values ​​of the injection speed in each of a plurality of divided areas obtained by arbitrarily dividing the low speed region.

[0006] [2] The casting molding apparatus described in [1] above further comprises a judgment unit for judging the quality of the casting, wherein the judgment unit judges the quality of the casting based on the results of comparing the maximum and minimum values ​​of the injection speed with target values ​​in each of a plurality of divided areas obtained by arbitrarily dividing the low speed range.

[0007] [3] In the casting molding apparatus described in [1] or [2] above, the high-speed area is provided after the low-speed area, the speed analysis unit analyzes the injection speed in each of a plurality of divided areas obtained by arbitrarily dividing the high-speed area, and the number N1 of the plurality of divided areas in the low-speed area is greater than the number N2 of the plurality of divided areas in the high-speed area.

[0008] [4] In the casting molding apparatus described in any one of [1] to [3] above, the speed analysis unit further calculates the average value of the injection speed in each of a plurality of divided areas obtained by arbitrarily dividing the low speed region.

[0009] [5] A method for producing a casting using a casting molding device provided with a fixed mold, a movable mold, and a cavity formed by the fixed mold and the movable mold, comprising: an injection process for injecting molten metal into the cavity; an injection control process for controlling the injection speed of the molten metal in the injection process; and a speed analysis process for analyzing the injection speed in the injection process, wherein the injection process has a low speed range in which the injection speed is controlled to follow a set value, and a high speed range in which the injection speed is controlled to follow a set value that is higher than the set value in the low speed range, and wherein the speed analysis process determines the maximum and minimum values ​​of the injection speed in each of a plurality of divided areas obtained by arbitrarily dividing the low speed range. [Effects of the Invention]

[0010] According to the present disclosure, a casting molding apparatus and a casting manufacturing method are provided that can perform high-precision quality evaluation of castings and simplify the work of eliminating factors that affect quality. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of a casting apparatus. [Figure 2] FIG. 2 is a block diagram illustrating an example of a functional configuration of the control device. [Figure 3] FIG. 3 is a block diagram illustrating an example of a hardware configuration of the control device. [Figure 4] FIG. 4 is a flowchart showing an example of a process flow relating to a process for obtaining a casting. [Figure 5] FIG. 5 is a flowchart showing an example of a processing flow relating to quality evaluation of a casting. [Figure 6] FIG. 6 is a graph showing an example of the change in injection speed over time in the low speed range of the injection process. [Figure 7] FIG. 7 is a graph showing an example of the change in injection speed over time in the high-speed range of the injection process. [Figure 8]FIG. 8 is a schematic diagram showing an example of a monitor on which the quality evaluation results of a casting are displayed. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment will be described below with reference to the drawings. In the description, the same elements or elements having the same functions are designated by the same reference numerals, and redundant description will be omitted.

[0013] [Casting molding equipment] FIG. 1 schematically shows a casting molding apparatus 1 according to one embodiment. The casting molding apparatus 1 is an apparatus for producing a casting by filling a mold with molten metal (hereinafter referred to as "molten metal") and molding it. The molten metal is, for example, an aluminum alloy. The casting molding apparatus 1 is also referred to as a die-casting machine or die-casting apparatus. The casting molding apparatus 1 includes, for example, a casting section 10, an injection section 20, an injection cylinder 30, a hydraulic drive section 40, a position sensor 48, and a control device 50. Each element included in the casting molding apparatus 1 will be described below.

[0014] (Casting Department) The casting section 10 is a section where a cavity having a shape corresponding to the cast product is formed by a pair of molds. The casting section 10 has a fixed mold 11 and a movable mold 12. The fixed mold 11 and the movable mold 12 are attached to a mold clamping device, and the fixed mold 11 and the movable mold 12 are clamped together by driving the movable mold 12 with a drive unit connected to the movable mold 12. Clamping the fixed mold 11 and the movable mold 12 forms a cavity 13 having a shape corresponding to the cast product and a runner 14 communicating with the cavity 13.

[0015] Cavity 13 is connected to injection section 20 via runner 14 (runner 14 and gate), and molten metal is filled into cavity 13. Thus, casting molding apparatus 1 is provided with stationary mold 11, movable mold 12, and cavity 13. Casting molding apparatus 1 obtains a cast product through an injection process in which molten metal is injected into cavity 13.

[0016] (Injection part) The injection part 20 is a part that injects the molten metal into the cavity 13. The molten metal is injected by the injection part 20, thereby filling the cavity 13 with the molten metal. The injection part 20 has an injection sleeve 21, a plunger 22, and a plunger rod 23.

[0017] The injection sleeve 21 is a member that forms a space for temporarily storing molten metal. The injection sleeve 21 is formed, for example, in a cylindrical shape that extends horizontally in one direction. The injection sleeve 21 is provided with a pouring port 24. The casting molding apparatus 1 supplies the molten metal from the pouring port 24 into the injection sleeve 21 using a molten metal supply device or the like.

[0018] The plunger 22 is a member that moves the molten metal supplied inside the injection sleeve 21 toward the cavity 13. The plunger 22 is also referred to as a plunger tip. The plunger 22 is provided inside the injection sleeve 21 so as to be able to advance and retreat (move). In the present disclosure, with regard to the movement of the plunger 22, the direction in which the plunger 22 approaches the cavity 13 is referred to as "forward" or "forward," and the movement of the plunger 22 moving forward is referred to as "advancing." Furthermore, the direction in which the plunger 22 moves away from the cavity 13 is referred to as "rear" or "rearward," and the movement of the plunger 22 moving backward is referred to as "retreating," and the forward and rearward movements are collectively referred to as "advancing and retreating." In FIG. 1 , the front (forward) direction is represented by an arrow marked with "F," and the rear (rear) direction is represented by an arrow marked with "B."

[0019] As the plunger 22 moves forward, the molten metal in the injection sleeve 21 is injected (injected and filled) into the cavity 13 via the runner 14. As the plunger 22 moves backward, the molten metal is supplied from the pouring port 24 into the injection sleeve 21, with the plunger 22 positioned behind the pouring port 24.

[0020] (injection cylinder) The injection cylinder 30 is a member that operates the plunger 22 of the injection unit 20. The injection cylinder 30 is a hydraulically driven cylinder. The injection cylinder 30 has a cylinder container 31, a cylinder rod 32, a connecting portion 33, and a cylinder head 34.

[0021] The cylinder container 31 forms a space for some of the members included in the injection cylinder 30 to move forward and backward. The cylinder container 31 is formed, for example, in a cylindrical shape so as to extend along the front-to-rear direction in which the plunger 22 operates. The front end (tip) of the cylinder rod 32 is detachably connected to the plunger rod 23 of the injection unit 20 via a connecting part 33. A cylinder head 34 is connected to the rear end of the cylinder rod 32, and the cylinder rod 32 and the cylinder head 34 are integrated.

[0022] A space is formed inside the cylinder container 31 behind the cylinder head 34, and this space is referred to as the "head-side hydraulic chamber 34a." A space is formed inside the cylinder container 31 forward of the cylinder head 34, and this space is referred to as the "rod-side hydraulic chamber 32a." By controlling the flow of hydraulic oil to each of the rod-side hydraulic chamber 32a and the head-side hydraulic chamber 34a, the speed (injection speed) of the plunger 22 during its forward movement and the speed during its backward movement may be controlled.

[0023] The injection cylinder 30 may have a speed adjustment valve 35. The speed adjustment valve 35 is a valve for controlling the speed of the plunger 22. The speed adjustment valve 35 adjusts the amount of hydraulic oil discharged from the rod-side hydraulic chamber 32a by adjusting its opening degree. The speed of the plunger 22 is controlled by adjusting the amount of hydraulic oil discharged from the rod-side hydraulic chamber 32a (i.e., meter-out control is performed). Instead of or in addition to meter-out control, the speed of the plunger 22 may be adjusted by adjusting the amount of hydraulic oil supplied to the head-side hydraulic chamber 34a (i.e., meter-in control may be performed).

[0024] (Hydraulic drive unit) The hydraulic drive unit 40 is a part that supplies hydraulic oil for operating the plunger 22 and hydraulic oil for increasing the pressure of the molten metal in the cavity 13 to the injection cylinder 30. The hydraulic drive unit 40 has, for example, an accumulator 41, an accumulator 42, and a switching valve 43.

[0025] The accumulator 41 is a device that delivers hydraulic oil to the injection cylinder 30 in the injection process to operate the plunger 22. The accumulator 41 includes, for example, a sealed container 41a, a hydraulic oil chamber 41b, a gas chamber 41c, and an airtight member 41d. The sealed container 41a forms spaces that become the hydraulic oil chamber 41b and the gas chamber 41c, and houses the airtight member 41d. The hydraulic oil chamber 41b stores hydraulic oil. The gas chamber 41c stores pressurized gas. The airtight member 41d is movably disposed within the sealed container 41a and airtightly separates the hydraulic oil chamber 41b and the gas chamber 41c.

[0026] The hydraulic oil chamber 41b of the accumulator 41 is connected to the head-side hydraulic chamber 34a of the injection cylinder 30. When pressurized gas is supplied to the gas chamber 41c, the airtight member 41d is pressed and moved. As the airtight member 41d moves, hydraulic oil for injection is supplied from the hydraulic oil chamber 41b to the head-side hydraulic chamber 34a.

[0027] The accumulator 42 is a device that delivers hydraulic oil to the injection cylinder 30 during the pressure-increasing process, which applies pressure to the molten metal in the cavity 13 by driving the plunger 22. The pressure-increasing process is a process of increasing the pressure of the molten metal in the cavity 13 after the injection process. The accumulator 42 includes, for example, a sealed container 42a, a hydraulic oil chamber 42b, a gas chamber 42c, and an airtight member 42d. The sealed container 42a forms spaces that become the hydraulic oil chamber 42b and the gas chamber 42c, and houses the airtight member 42d. The hydraulic oil chamber 42b stores hydraulic oil. The gas chamber 42c stores pressurized gas. The airtight member 42d is movably disposed within the sealed container 42a and airtightly separates the hydraulic oil chamber 42b and the gas chamber 42c.

[0028] The hydraulic oil chamber 42b of the accumulator 42 is connected to the head-side hydraulic chamber 34a of the injection cylinder 30. When pressurized gas is supplied to the gas chamber 42c, the airtight member 42d is pressed and moved. As the airtight member 42d moves, hydraulic oil for boosting pressure is supplied from the hydraulic oil chamber 42b to the head-side hydraulic chamber 34a.

[0029] The switching valve 43 is a member that switches between accumulators that supply hydraulic oil to the injection cylinder 30 (head-side hydraulic chamber 34a). The switching valve 43 switches between a state in which hydraulic oil for injection is supplied from the accumulator 41 to the injection cylinder 30, and a state in which hydraulic oil for boosting is supplied from the accumulator 42 to the injection cylinder 30. The switching valve 43 may be any valve that can switch between these two states. The switching valve 43 operates based on an operation command from the control device 50.

[0030] (position sensor) The position sensor 48 is a sensor that acquires information indicating the position of the plunger 22. The position of the plunger 22 may be the position of the tip of the plunger 22 in the front-rear direction in which the plunger 22 moves. The position sensor 48 is provided, for example, in the injection cylinder 30, and acquires information indicating the position of the plunger 22 by detecting the position of the connecting portion 33, the cylinder rod 32, or the cylinder head 34. The position sensor 48 may be provided in the injection unit 20 instead of the injection cylinder 30. The position sensor 48 may directly detect the position of the plunger 22, or may acquire information indicating the position of the plunger 22 by detecting the position of the plunger rod 23. The position sensor 48 outputs the detection result to the control device 50.

[0031] The control device 50 is a device that controls at least some of the elements included in the casting molding apparatus 1. The control device 50 is configured with one or more computers. The control device 50 controls the controlled objects to execute the processes for obtaining a casting, and also performs calculations to evaluate the quality of the obtained casting.

[0032] A monitor 52 may be connected to the control device 50. The monitor 52 is a device for outputting (displaying) the results of calculations performed by the control device 50 to the operator of the casting apparatus 1. The monitor 52 may be any device capable of displaying information, and may be, for example, a liquid crystal display.

[0033] 2, the control device 50 has, for example, as functional components (hereinafter referred to as "functional blocks"), a position information acquisition unit 62, a speed calculation unit 64, an injection control unit 66, a pressure increase start unit 68, a speed analysis unit 70, a determination unit 72, and an output unit 74. The processing executed by these functional blocks corresponds to the processing executed by the control device 50.

[0034] The position information acquisition unit 62 acquires the measurement results from the position sensor 48 as information indicating the position of the plunger 22. The position information acquisition unit 62 may repeatedly acquire the measurement results from the position sensor 48 at a predetermined cycle (at each predetermined cycle). The speed calculation unit 64 calculates the speed of the plunger 22 based on the information indicating the position of the plunger 22. The speed of the plunger 22 corresponds to the injection speed of the molten metal that is the target of movement by the plunger 22. In other words, controlling the speed of the plunger 22 means controlling the injection speed of the molten metal. The speed calculation unit 64 may repeatedly calculate the speed of the plunger 22 at a predetermined cycle (at each predetermined cycle). The speed calculation unit 64 may store the calculation results of the speed for each cycle.

[0035] In the injection process, the injection control unit 66 controls the speed of the plunger 22 (the injection speed of the molten metal). For example, the injection control unit 66 controls the speed adjustment valve 35 so that the speed of the plunger 22 follows the target speed. Based on the deviation between the speed calculation result by the speed calculation unit 64 and the target speed, the injection control unit 66 may adjust the opening of the speed adjustment valve 35 so as to reduce the deviation.

[0036] The pressure increase start unit 68 outputs a start command to start the pressure increase process. The pressure increase start unit 68 outputs the start command when, for example, the position of the plunger 22 indicated by the measurement value by the position sensor 48 reaches a preset start position. In one example, the pressure increase start unit 68 outputs, as the start command, a signal to the switching valve 43 to switch from a state in which the accumulator 41 and the injection cylinder 30 are connected to a state in which the accumulator 42 and the injection cylinder 30 are connected.

[0037] The speed analysis unit 70 analyzes the speed of the plunger 22 during the injection process. Analyzing the speed of the plunger 22 means analyzing the injection speed of the molten metal. The judgment unit 72 judges whether the casting is good or bad. The judgment unit 72 judges whether the casting being judged is good or bad based on the analysis results by the speed analysis unit 70. Details of the speed analysis by the speed analysis unit 70 and the judgment of good or bad by the judgment unit 72 will be described later. The output unit 74 outputs at least one of the analysis results by the speed analysis unit 70 and the judgment results by the judgment unit 72. The output unit 74 may output both the analysis results by the speed analysis unit 70 and the judgment results by the judgment unit 72 to the monitor 52.

[0038] 3 schematically shows the hardware configuration of the control device 50. The control device 50 includes, for example, a circuit 91. The circuit 91 includes a processor 92, a memory 93, a storage 94, an input / output port 95, and a timer 96. The storage 94 is configured with one or more non-volatile memory devices such as a flash memory or a hard disk. The storage 94 stores programs for configuring each of the above-mentioned functional blocks.

[0039] The memory 93 is composed of one or more volatile memory devices such as a random access memory. The memory 93 temporarily stores programs loaded from the storage 94. The processor 92 is composed of one or more arithmetic devices such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The processor 92 configures the above-mentioned functional blocks by executing the programs loaded into the memory 93. The results of calculations by the processor 92 are temporarily stored in the memory 93. The input / output port 95 inputs and outputs information to and from the position sensor 48, the speed adjustment valve 35, the switching valve 43, the monitor 52, etc. in response to a request from the processor 92. The timer 96 measures elapsed time by, for example, counting reference pulses at a fixed interval.

[0040] The hardware configuration of the control device 50 is not necessarily limited to configuring each functional block by a program. For example, each functional block of the control device 50 may be configured by a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) that integrates such logic circuits. The control device 50 may also be configured by multiple computers connected to each other so that they can communicate with each other.

[0041] [Casting manufacturing method] Next, as an example of a method for producing a casting, a method for obtaining (producing) a casting using the above-described casting molding apparatus 1 will be described with reference to Figures 4 to 8. This method includes at least an injection step, an injection control step, and a speed analysis step.

[0042] The injection process is a process of injecting molten metal into cavity 13. The injection control process is a process of controlling the speed of plunger 22 (the injection speed of the molten metal) during the injection process. The injection process has a low-speed region where the speed of plunger 22 is controlled to follow a set value, and a high-speed region where the speed of plunger 22 is controlled to follow a set value that is higher than the set value in the low-speed region.

[0043] The speed analysis step is a step of analyzing the speed of the plunger 22 (the injection speed of the molten metal) during the injection step. In the speed analysis step, the maximum and minimum injection speeds are determined for each of a plurality of divided areas obtained by arbitrarily dividing the low speed region.

[0044] 4 illustrates a series of processes executed by the control device 50 as a process flow for molding (manufacturing) one casting. The control device 50 executes step S11 with the plunger 22 placed in its initial position and the injection sleeve 21 being supplied with an amount of molten metal required to produce one casting. In step S11, for example, the injection control unit 66 starts a low-speed injection process. The low-speed injection process is a process in which the plunger 22 is operated at a slower speed than the high-speed injection process described below. In step S11, the injection control unit 66 controls the hydraulic drive unit 40 to start supplying hydraulic oil from the accumulator 41 to the head-side hydraulic chamber 34a of the injection cylinder 30.

[0045] After step S11 is executed, the position information acquisition unit 62 continues measurement using the position sensor 48, and the speed calculation unit 64 continues calculating the speed of the plunger 22 and storing the calculation results. By executing step S11, the plunger 22 starts moving forward. As a result, the molten metal in the injection sleeve 21 starts moving toward the runner 14 and the cavity 13. In the low-speed injection process, the injection control unit 66 may adjust the aperture of the speed adjustment valve 35 so that the moving speed of the plunger 22 follows a set value. Note that in the low-speed injection process, the injection control unit 66 may control the speed of the plunger 22 by adjusting the amount of hydraulic oil supplied from the accumulator 41 to the head-side hydraulic chamber 34a, instead of or in addition to the aperture of the speed adjustment valve 35.

[0046] Next, the control device 50 executes step S12. In step S12, for example, the injection control unit 66 waits until the plunger 22 reaches a preset first position. As a result, the low-speed injection process continues until the plunger 22 reaches the first position, and speed feedback control is executed so that the moving speed of the plunger 22 follows the set value for the low-speed injection process. As the low-speed injection process continues, most of the air that was present in the injection sleeve 21 together with the molten metal at the time step S11 was executed is discharged via the fixed mold 11 and the movable mold 12. The first position is set, for example, so that the movement of the plunger 22 to the first position prevents the molten metal from entering the cavity 13 and results in the entire area of ​​the runner 14 being filled with the molten metal.

[0047] Next, the control device 50 executes step S13. In step S13, for example, the injection control unit 66 executes a high-speed injection process. In step S13, the injection control unit 66 may control the hydraulic drive unit 40 so that a larger amount of hydraulic oil is supplied from the accumulator 41 to the head-side hydraulic chamber 34a than the amount of hydraulic oil supplied in the low-speed injection process.

[0048] By executing step S13, the plunger 22 moves forward at a faster speed. Then, the molten metal in the runner 14 and the injection sleeve 21 begins to be introduced into the cavity 13. In the high-speed injection process, the injection control unit 66 may adjust the aperture of the speed adjustment valve 35 so that the movement speed of the plunger 22 follows a set value. The set value (set range) of the movement speed of the plunger 22 in the speed control in the high-speed injection process is set to be larger than the set value (set range) of the movement speed in the speed control in the low-speed injection process. Note that in the high-speed injection process, the injection control unit 66 may control the speed of the plunger 22 by adjusting the amount of hydraulic oil supplied from the accumulator 41 to the head-side hydraulic chamber 34a instead of or in addition to the aperture of the speed adjustment valve 35.

[0049] Next, the control device 50 executes step S14. In step S14, for example, the injection control unit 66 waits until the plunger 22 reaches a preset second position. As a result, the high-speed injection process continues until the plunger 22 reaches the second position, and speed feedback control is executed so that the movement speed of the plunger 22 follows the set value for the high-speed injection process. The second position is set, for example, so that the entire cavity 13 is filled with the molten metal when the plunger 22 moves to the second position.

[0050] As described above, the injection process for injecting the molten metal into the cavity 13 includes a low-speed injection process (low-speed region) and a high-speed injection process (high-speed region). The high-speed region is provided after the low-speed region. The low-speed region may account for approximately two-thirds of the entire injection process.

[0051] In the low-speed range, for example, the plunger 22 operates at a low speed so as to minimize the amount of air in the injection sleeve 21 being mixed into the molten metal. If the actual speed of the plunger 22 in this low-speed range deviates significantly from the set value for the movement speed in the low-speed range, an event that affects the quality of the casting may occur. Specifically, if the actual speed of the plunger 22 becomes too much higher than the set value for the movement speed in the low-speed range, the amount of air mixed into the molten metal may increase. On the other hand, if the actual speed of the plunger 22 becomes too much lower than the set value for the movement speed in the low-speed range, a portion of the molten metal may solidify over time.

[0052] In the high-speed range, the plunger 22 operates at a high speed to avoid defects in the appearance of the casting, for example. If the actual speed of the plunger 22 in this high-speed range deviates significantly from the set value of the moving speed in the high-speed range, an event that affects the quality of the casting (e.g., the appearance quality) may occur. Specifically, if the actual speed of the plunger 22 becomes too much higher than the set value of the moving speed in the high-speed range, the resistance between the molten metal and the mold increases, which may cause seizure. If the actual speed of the plunger 22 becomes too much lower than the set value of the moving speed in the high-speed range, a portion of the molten metal may solidify at a protruding portion in the cavity 13.

[0053] From the above, by analyzing whether the actual speed of plunger 22 deviates significantly from the set value in both the low-speed and high-speed ranges, or in the low-speed range which accounts for approximately two-thirds of the injection process, it is possible to evaluate whether or not quality defects have occurred in the casting (the possibility of such occurrence).

[0054] Next, the control device 50 executes step S15. In step S15, for example, the control device 50 controls the casting apparatus 1 to execute a pressure-increasing step. The pressure-increasing start unit 68 outputs a start command to start the pressure-increasing step of step S15. The pressure-increasing start unit 68 may output a signal (start command) to the switching valve 43 to stop the supply of hydraulic oil for injection from the accumulator 41 and to supply hydraulic oil for pressure-increasing from the accumulator 42 to the head-side hydraulic chamber 34a. This causes hydraulic oil for pressure-increasing to be supplied to the head-side hydraulic chamber 34a, and the force that tends to move the plunger 22 forward applies pressure to the molten metal in the cavity 13. After the start of execution of step S15, the accumulator 42 may supply hydraulic oil for pressure-increasing to the head-side hydraulic chamber 34a so that the pressure applied to the molten metal in the cavity 13 increases.

[0055] Next, the control device 50 executes step S16. In step S16, for example, the control device 50 controls the casting apparatus 1 to execute a pressure holding process. The pressure holding process is a process for compensating for solidification shrinkage that occurs as the molten metal that has been injected and filled (injected and filled) into the cavity 13 cools and solidifies. In one example, the control device 50 applies a force to move the plunger 22 forward, thereby pressing the molten metal in the cavity 13 and applying a pressure holding pressure.

[0056] Next, the control device 50 executes step S17. In step S17, for example, the control device 50 controls the casting apparatus 1 to execute a cooling process. The cooling process is a process for cooling the casting formed in the cavity 13. The casting is obtained by executing the above series of processes. After the above series of processes are executed, the fixed mold 11 and the movable mold 12 may be opened and the casting may be removed. Then, the control device 50 may cause a molten metal supply device or the like to supply new molten metal into the injection sleeve 21, and then control the casting apparatus 1 to execute the series of processes of steps S11 to S17 again.

[0057] 5 shows a process flow for evaluating the quality of a casting, which is a series of processes executed by the control device 50 after the pressure increasing process is started. In this series of processes, the control device 50 first executes step S21. In step S21, for example, the speed analysis unit 70 analyzes the speed of the plunger 22 in the low-speed region of the injection process. The speed analysis unit 70 determines at least the maximum and minimum values ​​of the speed of the plunger 22 in each of a plurality of divided areas obtained by arbitrarily dividing the low-speed region (by arbitrarily dividing it on the time axis).

[0058] FIG. 6 shows a graph representing the change in the speed of plunger 22 over time during a period including the low-speed region of the injection process. In the graph in FIG. 6, the horizontal axis represents time and the vertical axis represents speed. The low-speed region of the injection process (low-speed injection process) begins at time t0 and ends at time t2. That is, from time t2 onward, the high-speed injection process is performed. The end point of the period of the low-speed region to be divided into multiple divided areas may be time t2. In the graph in FIG. 6, the start point of the period of the low-speed region to be divided into multiple divided areas is represented by time t1. Time t1 may coincide with time t0 or may be set at a point when a predetermined initial time has elapsed from time t0 (for example, when the rate of increase in speed becomes small). Note that, although the example shows a case where time t2 is set as the point of switching between the low-speed region and the high-speed region, time t2 may be set at any point in time within the low-speed region.

[0059] The period from time t1 to time t2 (the target period) is divided on the time axis to set multiple divided areas. The number (N1) of multiple divided areas in the low-speed region may be two or more, three or more, four or more, or five or more. The period from time t1 to time t2 may be equally divided to set multiple divided areas. In the example shown in FIG. 6, the low-speed region is divided into five divided areas. In FIG. 6, the five divided areas are labeled "A," "B," "C," "D," and "E," in that order. Note that in the example shown in FIG. 6, the time axis is divided into multiple areas, but it may also be divided into multiple areas according to the position (movement distance) of the plunger 22. In the graph shown in FIG. 6, the horizontal axis may be the position (movement distance) of the plunger 22. Time t0, time t1, and time t2 may correspond to distance s0, distance s1, and distance s2, respectively, and the time axis may be divided into multiple areas.

[0060] The speed analysis unit 70 may determine, for each divided area, the maximum, minimum, and average values ​​of the speed of the plunger 22. In one example, the speed analysis unit 70 determines, for divided area A, the maximum, minimum, and average values ​​of the speed in that area. Then, for divided area B, divided area C, divided area D, and divided area E, the speed analysis unit 70 determines, in the same manner as for divided area A, the maximum, minimum, and average values ​​of the speed in that area.

[0061] Next, the control device 50 executes step S22. In step S22, for example, the speed analysis unit 70 analyzes the speed of the plunger 22 in the high-speed region of the injection process. The speed analysis unit 70 may analyze the speed of the plunger 22 in each of a plurality of divided areas obtained by arbitrarily dividing the high-speed region (by arbitrarily dividing it on the time axis). In one example, the speed analysis unit 70 determines at least the maximum and minimum values ​​of the speed of the plunger 22 for each divided area in the high-speed region.

[0062] FIG. 7 shows a graph representing the change in the speed of plunger 22 over time during a period including the high-speed region of the injection process. In the graph in FIG. 7, as in FIG. 6, the horizontal axis represents time and the vertical axis represents speed, but the scale of each axis is different from the corresponding scale in FIG. 6. At time t2, the low-speed region (low-speed injection process) switches to the high-speed region (high-speed injection process), and at time t3, the high-speed region ends. In other words, from time t3 onwards, the pressure boosting process is carried out. The start point of a period within the high-speed region that is to be divided into multiple areas may be time t2, and the end point of the period may be time t3.

[0063] The period from time t2 to time t3 (the target period) is divided on a time axis to set multiple divided areas. The number (N2) of multiple divided areas in the high speed range may be 2 or more, 3 or more, 4 or more, or 5 or more. The number (N2) of multiple divided areas in the high speed range may be less than the number (N1) of multiple divided areas in the low speed range. That is, multiple divided areas may be set in each of the low speed range and the high speed range so that N1 > N2. Multiple divided areas may be set by equally dividing the period from time t2 to time t3. In the example shown in FIG. 7, the high speed range is divided into two divided areas. In FIG. 7, the two divided areas are labeled "A" and "B" in that order. In the high speed range, divided areas may also be obtained by arbitrarily dividing the high speed range on a distance axis instead of a time axis.

[0064] The speed analysis unit 70 may determine, for each divided area in the high-speed range, the maximum value, minimum value, and average value of the speed of the plunger 22. In one example, the speed analysis unit 70 determines, for each of divided areas A and B in the high-speed range, the maximum value, minimum value, and average value of the speed in the corresponding area.

[0065] When the start point of divided area A is set at the time when the speed is switched to the high-speed range, the speed of plunger 22 increases for a while immediately after the switch due to the change in the target speed (change to the set value for the high-speed range). Therefore, if the minimum value is found by observing the entire divided area A, the minimum value will be the value at the start point of divided area A. To avoid this, the speed analysis unit 70 may specify the value at which the speed is smallest after the maximum speed in divided area A (the first divided area) in the high-speed range as the minimum value of divided area A. Note that, in the divided area A in the low-speed range, the speed analysis unit 70 may similarly determine the value at which the speed is smallest after the maximum speed as the minimum value of divided area A.

[0066] 5, next, the control device 50 executes step S23. In step S23, for example, the determination unit 72 determines whether the casting to be determined is a conforming product based on the results of the speed analysis in steps S21 and S22. In this case, when determining whether the casting to be determined is a conforming product and evaluating its quality, the determination unit 72 uses the results of the analysis of the speed (injection speed) of the plunger 22 in the injection process performed to obtain the casting.

[0067] The determination unit 72 may determine the quality of the casting based on the results of comparing the maximum and minimum values ​​of the speed of the plunger 22 with a first target value (target value) in each of the multiple divided areas in the low-speed range. The first target value may be a value based on a set value (set range) that represents the target speed of the plunger 22 in the low-speed injection process. The determination unit 72 may also determine the quality of the casting based on the results of comparing the average value of each divided area with the first target value. The determination unit 72 may determine, for each divided area, whether the maximum, minimum, and average values ​​of the speed of the plunger 22 fall outside a first target range that is determined by adding and subtracting a predetermined value to the first target value. The upper limit of the first target range is obtained by adding the predetermined value to the first target value, and the lower limit of the first target range is obtained by subtracting the predetermined value from the first target value.

[0068] The determination unit 72 may determine the quality of the casting based on the results of comparing the maximum and minimum values ​​of the speed of the plunger 22 with a second target value in each of the multiple divided areas in the high-speed range. The second target value may be a value based on a set value (set range) that represents the target speed of the plunger 22 in the high-speed injection process. The determination unit 72 may also determine the quality of the casting based on the results of comparing the average value of each divided area with the second target value. The determination unit 72 may determine, for each divided area, whether the maximum, minimum, and average values ​​of the speed of the plunger 22 fall outside a second target range that is determined by adding and subtracting a predetermined value to the second target value. The upper limit of the second target range is obtained by adding the predetermined value to the second target value, and the lower limit of the second target range is obtained by subtracting the predetermined value from the second target value.

[0069] The determination unit 72 may determine that the casting to be determined is not conforming or is a defective product when at least one of the maximum value, minimum value, and average value of the speed of the plunger 22 is outside the corresponding target range in either the low speed region or the high speed region. The determination unit 72 may determine that the casting to be determined is conforming in terms of injection speed when all of the maximum value, minimum value, and average value of the speed of the plunger 22 are within the corresponding target range in all of the low speed region and the high speed region.

[0070] Next, the control device 50 executes step S24. In step S24, for example, the output unit 74 outputs information indicating the analysis results of steps S21 and S22 and the determination result of step S23 (hereinafter referred to as "result information"). The output unit 74 may output the result information to the monitor 52, thereby causing the result information to be displayed on the monitor 52. FIG. 8 schematically shows the monitor 52 in a state where the result information is displayed.

[0071] As shown in FIG. 8 , the output unit 74 may display the maximum, minimum, and average values ​​of the speed for each divided area on the monitor 52. When the determination unit 72 determines that a value such as a maximum value is outside the corresponding target range, the output unit 74 may display the value on the monitor 52 in a display mode different from normal (for example, by changing the color or background color). In this way, by changing the display mode of the value outside the target range, the determination result by the determination unit 72 that the casting is not conforming or is defective may be displayed on the monitor 52. Note that, unlike the example shown in FIG. 8 , the output unit 74 may directly display information indicating the determination result of the determination unit 72 on the monitor 52 (for example, a message or warning indicating that the casting is not conforming may be displayed on the monitor 52).

[0072] The control device 50 may execute the series of processes of steps S21 to S24 each time one casting is obtained by the series of processes shown in Fig. 4. The control device 50 may execute the series of processes of steps S21 to S24 during a period that overlaps with at least a portion of the period during which steps S15 to S17 are executed. The control device 50 may execute the series of processes of steps S21 to S24 after step S17 is completed.

[0073] [Variations] The series of processes shown in each of Figures 4 and 5 are examples and can be modified as appropriate. In the series of processes described above, the control device 50 may execute one step and the next step in parallel, or may execute the steps in an order different from that of the example described above. The control device 50 may omit any step, or may execute a process in any step that is different from that of the example described above.

[0074] In step S24, the output unit 74 may output information indicating the determination result in step S23 to a device that performs a process subsequent to the molding of the casting by the casting molding device 1, instead of or in addition to the monitor 52. For example, when the determination unit 72 determines that the casting being judged is not a conforming product, the output unit 74 may send a signal indicating that the casting is not a conforming product to a device that sorts the castings. The device that sorts the castings may then sort the castings into those that are determined to be conforming products and those that are determined to be not conforming products.

[0075] Control device 50 may execute steps S21 and S22 without executing step S23. Then, in step S24, control device 50 may display the results of the speed analysis in steps S21 and S22 on monitor 52. In this case, an operator of casting apparatus 1 may determine the quality of the cast product from the results of the speed analysis displayed on monitor 52.

[0076] The speed analysis unit 70 may analyze the speed of the plunger 22 in the low speed range, but may not analyze the speed of the plunger 22 in the high speed range. In this case, the determination unit 72 may determine whether the casting to be determined is a non-defective product based on the analysis result of the speed in the low speed range, without using the analysis result of the speed in the high speed range.

[0077] <Setting divided areas according to plunger movement distance> In the examples shown in FIGS. 6 and 7 described above, the injection speed-time graph is divided into a plurality of areas on the time axis, but it is also possible to use the moving distance of the plunger 22 instead of time and divide the graph into a plurality of areas on the axis of this moving distance, and find the maximum, minimum, and average values ​​of the speed in each area.

[0078] In the above example, the control device 50 that controls the manufacturing process for forming a casting includes the speed analysis unit 70, the determination unit 72, and the output unit 74. Alternatively, a computer for quality evaluation (quality evaluation device) separate from the control device 50 may include the speed analysis unit 70, the determination unit 72, and the output unit 74.

[0079] The casting molding apparatus 1 may be configured in any manner as long as it is provided with a fixed mold, a movable mold, and a cavity formed by the fixed mold and the movable mold, and is capable of obtaining a casting through the injection process. In one of the various examples described above, at least some of the features described in the other examples may be combined.

[0080] Summary of this disclosure The casting molding apparatus 1 described above is provided with a fixed mold 11, a movable mold 12, and a cavity 13 formed by the fixed mold 11 and the movable mold 12, and is an apparatus for obtaining a cast product through an injection process in which molten metal is injected into the cavity 13. This casting molding apparatus 1 is equipped with an injection control unit 66 that controls the injection speed of the molten metal during the injection process, and a speed analysis unit 70 that analyzes the injection speed during the injection process. The injection process has a low-speed range in which the injection speed is controlled to follow a set value, and a high-speed range in which the injection speed is controlled to follow a set value higher than the set value in the low-speed range. The speed analysis unit 70 calculates the maximum and minimum injection speeds for each of a plurality of divided areas obtained by arbitrarily dividing the low-speed range.

[0081] As described above, if the speed of the plunger 22, which corresponds to the injection speed, deviates significantly from the set value in the low-speed range, an event that affects the quality of the casting may occur. Based on this, when evaluating whether the injection speed in the low-speed range is affecting the quality of the casting, the injection speed at one or more arbitrary locations in the low-speed range is extracted and evaluated. However, this evaluation method has a problem in that it cannot determine whether the quality is affected if the injection speed at locations other than the extracted locations is outside the appropriate range.

[0082] In contrast, the casting molding apparatus 1 divides the low-speed range into multiple areas and calculates the maximum and minimum injection speed values ​​for each area, allowing for more locations to determine whether the injection speed is within the appropriate range. This makes it possible to evaluate the quality of cast products with high accuracy. Furthermore, by dividing the area into multiple areas and evaluating each area individually, it is possible to quickly identify locations in the casting molding apparatus 1 where abnormalities have occurred, which is also useful for simplifying the process of eliminating factors that may have affected quality when an abnormality in the injection speed occurs.

[0083] The casting molding apparatus 1 described above may further include a judgment unit 72 that judges the quality of the cast product. The judgment unit 72 may judge the quality of the cast product based on the results of comparing the maximum and minimum injection speed values ​​with target values ​​in each of a plurality of divided areas obtained by arbitrarily dividing the low-speed range. In this case, the casting molding apparatus 1 itself (the apparatus itself) evaluates the quality of the cast product using the maximum and minimum values ​​for each divided area, which are the analysis results of the injection speed, so that quality evaluation can be performed with higher accuracy.

[0084] In the casting molding apparatus 1 described above, the high-speed region is provided after the low-speed region. The speed analysis unit 70 may also analyze the injection speed in each of multiple divided areas obtained by arbitrarily dividing the high-speed region. The number N1 of multiple divided areas in the low-speed region may be greater than the number N2 of multiple divided areas in the high-speed region. In the injection process, the execution period of the low-speed region tends to be longer than the execution period of the high-speed region. Therefore, by making the number N1 of divisions in the low-speed region greater than the number N2 of divisions in the high-speed region, the injection speed can be managed efficiently (e.g., identifying abnormalities, etc.).

[0085] In the casting molding apparatus 1 described above, the velocity analysis unit 70 may further calculate the average injection velocity for each of a plurality of divided areas obtained by arbitrarily dividing the low velocity range. In this case, the average value, in addition to the maximum and minimum values, can be used to evaluate the impact on the quality of the casting. This allows for more accurate quality evaluation.

[0086] The above-described casting manufacturing method is a method for obtaining a casting using a casting molding apparatus 1 equipped with a fixed mold 11, a movable mold 12, and a cavity 13 formed by the fixed mold 11 and the movable mold 12. This casting manufacturing method includes an injection process for injecting molten metal into the cavity 13, an injection control process for controlling the injection speed of the molten metal during the injection process, and a speed analysis process for analyzing the injection speed during the injection process. The injection process has a low-speed region in which the injection speed is controlled to follow a set value and a high-speed region in which the injection speed is controlled to follow a set value higher than the set value in the low-speed region. The speed analysis process determines the maximum and minimum injection speeds for each of multiple divided areas obtained by arbitrarily dividing the low-speed region. Similar to the casting molding apparatus 1, this casting manufacturing method is capable of highly accurate quality evaluation of castings. It is also useful for simplifying the process of eliminating factors affecting quality when an abnormality in the injection speed occurs. [Explanation of symbols]

[0087] 1...casting molding device, 11...fixed mold, 12...movable mold, 13...cavity, 20...injection unit, 30...injection cylinder, 40...hydraulic drive unit, 48...position sensor, 50...control device, 64...speed calculation unit, 66...injection control unit, 70...speed analysis unit, 72...judgment unit, 74...output unit.

Claims

1. A fixed mold; A movable mold; a cavity formed by the fixed mold and the movable mold; a casting molding apparatus for obtaining a casting product through an injection step of injecting a molten metal into the cavity, an injection control unit that controls an injection speed of the molten metal in the injection step; a speed analysis unit that analyzes the injection speed in the injection process; Equipped with the injection step has a low speed region in which the injection speed is controlled to follow a set value, and a high speed region in which the injection speed is controlled to follow a set value higher than the set value in the low speed region, The speed analysis unit calculates a maximum value and a minimum value of the injection speed in each of a plurality of divided areas obtained by arbitrarily dividing the low speed region. A casting molding device characterized by the above.

2. The casting molding apparatus according to claim 1, Further provided is a judgment unit for judging whether the casting is good or bad, The judgment unit judges whether the casting is good or bad based on a result of comparing the maximum and minimum values ​​of the injection speed with target values ​​in each of a plurality of divided areas obtained by arbitrarily dividing the low speed region. A casting molding device characterized by the above.

3. The casting molding apparatus according to claim 1 or 2, The high speed region is provided after the low speed region, the velocity analysis unit also analyzes the injection velocity in each of a plurality of divided areas obtained by arbitrarily dividing the high-speed region, The number N1 of the plurality of divided areas in the low speed range is greater than the number N2 of the plurality of divided areas in the high speed range. A casting molding device characterized by the above.

4. The casting molding apparatus according to claim 1 or 2, The velocity analysis unit further calculates an average value of the injection velocity in each of a plurality of divided areas obtained by arbitrarily dividing the low velocity region. A casting molding device characterized by the above.

5. A fixed mold; A movable mold; a cavity formed by the fixed mold and the movable mold; A casting manufacturing method for obtaining a casting using a casting molding apparatus provided with an injection step of injecting molten metal into the cavity; an injection control step of controlling an injection speed of the molten metal in the injection step; a speed analysis step of analyzing the injection speed in the injection step; Equipped with the injection step has a low speed region in which the injection speed is controlled to follow a set value, and a high speed region in which the injection speed is controlled to follow a set value higher than the set value in the low speed region, In the speed analysis step, the maximum value and the minimum value of the injection speed are obtained in each of a plurality of divided areas obtained by arbitrarily dividing the low speed region. A casting manufacturing method characterized by the above.

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