Die-casting machine injection filling method and die-casting machine

Abstract

To provide an injection and filling method of a die cast machine which correctly detects feeding completion to an injection sleeve and starts an advancement operation of a plunger.SOLUTION: In an injection and filling method of a die cast machine for injecting and filling molten metal fed into an injection sleeve into a mold cavity with an advancement operation of a plunger, the die cast machine comprises: a molten metal feeding unit which feeds molten metal to the injection sleeve via a molten metal feeding pipe; and a determination unit which determines feeding completion of the injection sleeve. The advancement operation of the plunger is started on the basis of a determination signal of the determination unit. The determination unit includes imaging means for imaging the inside from an observation window provided in the molten metal feeding pipe or measurement means, and determines the feeding completion to the injection sleeve on the basis of the image data of the imaging means or measurement data of the measurement means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an injection filling method for a die casting machine, in which molten metal supplied into an injection sleeve is injected and filled into a mold cavity by the forward movement of a plunger. [Background technology]

[0002] Casting using a die-casting machine with molten metal such as an aluminum alloy is performed as follows: First, a predetermined amount of molten metal is supplied from a molten metal holding furnace into the injection sleeve using a molten metal supply device (called molten metal supply). After molten metal supply is complete, the plunger is moved forward to inject and fill the molten metal in the injection sleeve into the mold cavity. After a pressure-boosting process to increase the filling density of the molten metal, a pressure-holding process to compensate for solidification shrinkage of the molten metal, and a molten metal cooling process, the cast product is removed from the mold cavity. This casting process is repeated until the planned number of cast products is obtained.

[0003] The following types of melt supply devices are used. For example, a pressurized melt supply device pressurizes the molten metal in a sealed melt holding furnace, discharging a predetermined amount of molten metal into a melt supply pipe, which then supplies the molten metal to the injection sleeve. The molten metal is pressed using pressurized gas or a piston cylinder. The amount of molten metal supplied to the injection sleeve (called the melt supply rate) is controlled by adjusting the pressure and supply time of the pressurized gas or the molten metal surface height, but because this is an indirect adjustment, the melt supply rate is prone to fluctuation. In addition, with a piston cylinder, the melt supply rate is said to fluctuate depending on the fluctuation in the molten metal surface height before and after the pressurization operation. Furthermore, because the molten metal is supplied to the injection sleeve via the melt supply pipe, there is a time lag between the completion of the discharge of the pressurized melt supply device and the actual completion of the supply of molten metal to the injection sleeve. This time lag between the fluctuation in the amount of molten metal supplied and the completion of the supply of molten metal causes fluctuations in the forward movement of the plunger, which is thought to result in variations in casting quality.

[0004] Another example is a ladle-type melt supply system that uses a heat-resistant container called a ladle to draw molten metal from a molten metal holding furnace, operates the ladle to transport the drawn molten metal to an injection sleeve, and tilts the ladle to supply molten metal to the injection sleeve. While the amount of molten metal supplied is adjusted by adjusting the ladle's operating position, it cannot be ruled out that molten metal may leak during ladle operation, resulting in a high probability of fluctuations in the amount of molten metal supplied and inducing fluctuations in casting quality. While molten metal leakage can be prevented by slowing down the ladle's operating speed, this is undesirable because it increases the ladle's operating time and causes fluctuations in the molten metal temperature.

[0005] Therefore, as shown in Patent Document 1, for example, a pressurized molten metal supply device has been proposed in which a piston cylinder is placed inside a molten metal holding furnace, the piston cylinder is operated to discharge the molten metal into a molten metal supply pipe, and an opening / closing valve placed at the outlet of the molten metal supply pipe facing the injection sleeve is operated to supply the molten metal. This is said to make it possible to stabilize the amount of molten metal supplied and accurately adjust the completion of molten metal supply. Furthermore, as shown in Patent Document 2, in a ladle-type melt supply device, it is proposed to supply molten metal from a ladle to an injection sleeve, measure the height of the molten metal surface in the injection sleeve with a melt surface detection sensor, calculate the amount of molten metal to be supplied, and correct the injection conditions based on the calculation results. This is said to be able to stabilize the casting quality regardless of fluctuations in the amount of molten metal to be supplied. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-188589 [Patent Document 2] Japanese Patent Publication No. 2020-49503 Summary of the Invention [Problem to be solved by the invention]

[0007] The method described in Patent Document 1 claims to adjust the timing and amount of molten metal supplied to the injection sleeve by adjusting the piston movement in the most upstream molten metal holding furnace and the valve movement in the most downstream. However, there are restrictions on the order in which these two operations can be adjusted. For example, if the valve movement in the most downstream position closes first while the piston movement in the most upstream position is discharging molten metal into the molten metal supply pipe, the molten metal pressure in the intermediate molten metal supply pipe may rise, potentially damaging the molten metal supply pipe. Therefore, the piston movement must be stopped first, and the valve movement must be confirmed before closing. Furthermore, to prevent air from entering the molten metal supply pipe, the molten metal supply pipe and valve movement are installed below the surface of the molten metal in the molten metal holding furnace. Therefore, due to the influence of gravity, the molten metal in the molten metal supply pipe flows out uncontrollably while the valve movement is open, regardless of the piston movement, resulting in fluctuations in the amount of molten metal supplied. Furthermore, although the temperature is controlled from the molten metal supply pipe to the opening and closing valve to prevent the molten metal from solidifying, it is structurally difficult to maintain the same temperature as the molten metal in the molten metal holding furnace. It is believed that fluctuations in the amount of molten metal supplied and fluctuations in the molten metal temperature will affect the casting quality.

[0008] The method described in Patent Document 2 aims to stabilize casting quality by measuring the actual amount of molten metal fed, assuming fluctuations in the amount of molten metal fed, and adjusting the injection conditions based on the measurement results. However, the molten metal in the injection sleeve immediately after feeding is wavy, and the molten metal surface height is unstable. Therefore, the molten metal surface height cannot be accurately measured until the molten metal surface stabilizes, and a time lag inevitably occurs between the completion of feeding and the start of injection. Furthermore, fluctuations in the amount of molten metal fed also cause fluctuations in the wavy state of the molten metal, resulting in fluctuations in both the time lag and the molten metal temperature. Furthermore, measuring the molten metal surface height does not measure the molten metal temperature. Therefore, complex measurement methods are required, such as using multiple measuring devices to simultaneously measure the molten metal surface height and molten metal temperature, which may increase the risk of malfunction and reduce operability and maintainability.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an injection filling method for a die casting machine that accurately detects the completion of supplying molten metal to the injection sleeve and starts the forward movement of the plunger. [Means for solving the problem]

[0010] The injection filling method for the die casting machine of the present invention comprises: In an injection filling method for a die casting machine, in which molten metal supplied into an injection sleeve is injected and filled into a mold cavity by the forward movement of a plunger, the method comprises a molten metal supply unit that supplies molten metal to the injection sleeve, and a discrimination unit that determines when molten metal supply to the injection sleeve has been completed, and the forward movement of the plunger is started based on a discrimination signal from the discrimination unit.

[0011] In the injection filling method for a die casting machine of the present invention, The molten metal supply section preferably discharges a predetermined amount of molten metal from a molten metal holding furnace using a pressurizing means, and supplies the discharged molten metal to the injection sleeve via a molten metal supply pipe.

[0012] In addition, in the injection filling method for a die casting machine of the present invention, The molten metal supply section preferably draws up a predetermined amount of molten metal from a molten metal holding furnace using a ladle, and supplies the drawn-up molten metal to the injection sleeve via a molten metal supply pipe.

[0013] Furthermore, in the injection filling method for the die casting machine of the present invention, It is preferable that the determination unit includes a photographing means for photographing the inside of the hot water supply pipe through an observation window provided in the hot water supply pipe, and determines whether hot water supply by the injection sleeve has been completed based on image data from the photographing means.

[0014] In addition, in the injection filling control method for a die casting machine of the present invention, It is preferable that the determination unit includes a measuring means for measuring the inside of the hot water supply pipe through an observation window provided in the hot water supply pipe, and determines whether hot water supply to the injection sleeve has been completed based on measurement data from the measuring means. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide an injection filling method for a die casting machine that accurately detects the completion of supplying molten metal to the injection sleeve and starts the forward movement of the plunger. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a conceptual diagram of a die-casting machine according to a first embodiment. FIG. [Figure 2] FIG. 2 is a flow diagram showing an injection filling method using the die casting machine of FIG. 1. [Figure 3] FIG. 10 is a conceptual diagram of a die-casting machine according to a second embodiment. [Figure 4] FIG. 3 is a flow diagram showing an injection filling method using the die casting machine of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0017] 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.

[0018] [First embodiment: die casting machine] First, the die-casting machine according to the first embodiment will be described with reference to Fig. 1. Fig. 1 shows a conceptual diagram of the die-casting machine according to the first embodiment. In the following description, the die-casting machine according to this embodiment is based on a horizontal die-casting machine, but the present invention is not limited to this.

[0019] The die-casting machine 100 shown in FIG. 1 includes a casting mold 10, an injection device 20, an injection control unit 40, a hot water supply unit 50, and a discrimination unit 60.

[0020] The casting mold 10 comprises a fixed mold 11 supported by a fixed platen (not shown), a movable mold 12 supported by a movable platen (not shown) and movable toward and away from the fixed mold 11, and a mold cavity 13 formed by clamping the fixed mold 11 and the movable mold 12. A casting is formed by injecting and filling molten metal such as an aluminum alloy into the mold cavity 13 using an injection device 20.

[0021] The injection device 20 includes a cylindrical injection sleeve 21 whose tip communicates with the mold cavity 13, and a plunger 22 that can advance and retreat within the injection sleeve 21. The plunger 22 and injection drive unit 30 are connected by a rod 23, and the injection drive unit 30 is operated to move the plunger 22 based on control commands from an injection control unit 40. Here, with regard to the movement of the plunger 22, the direction closer to the mold cavity 13 is defined as forward F, movement in the forward F direction is defined as forward movement, the direction away from the mold cavity 13 is defined as backward B, and movement in the backward B direction is defined as retreat movement. Furthermore, the position at which the retreat movement of the plunger 22 is completed is defined as a standby position BE, and the position at which the forward movement of the plunger 22 is completed is defined as an injection completion position FE. In other words, the plunger 22 moves forward and backward within the range between the standby position BE and the injection completion position FE.

[0022] A pouring port 24 is provided on the rear side B of the injection sleeve 21. While the plunger 22 is waiting at the waiting position BE, molten metal is supplied into the injection sleeve 21 from the molten metal supply unit 50 through the pouring port 24. The injection sleeve 21 and plunger 22 are provided with a cooling mechanism (not shown) including a flow path for a cooling medium such as cooling water, as needed. It is also preferable to apply a lubricant to the sliding surfaces of the injection sleeve 21 and plunger 22 to prevent wear and tear on the plunger 22, stabilize the sliding state, and suppress adhesion of molten metal residue.

[0023] The molten metal supply unit 50 includes a sealed molten metal storage furnace 51, a pressurized gas supply unit 52 that supplies pressurized gas, a molten metal discharge unit 54 that discharges the molten metal M from the molten metal storage furnace 51, a molten metal supply pipe 55 that causes the molten metal M to flow from the molten metal discharge unit 54 toward the pouring port 24 of the injection sleeve 21, and a pressurized gas control unit 53 that adjusts the operation of the pressurized gas supply unit 52. The pressurized gas control unit 53 and the injection control unit 40 are connected, and the injection control unit 40 adjusts the operation of the injection device 20 and the molten metal supply unit 50.

[0024] Based on a control command from the pressurized gas control unit 53, pressurized gas is supplied from the pressurized gas supply unit 52 to the pressurized chamber 52K in the molten metal storage furnace 51. The supply of pressurized gas pressurizes the pressurized chamber 52K, pressing against the surface of the molten metal M in the molten metal storage furnace 51, causing the molten metal M to be discharged from the molten metal discharge unit 54 to the molten metal supply pipe 55. The molten metal M flows through the molten metal supply pipe 55 and is supplied to the injection sleeve 21. At this time, the amount of molten metal supplied is adjusted by adjusting the supply pressure or amount of pressurized gas, the pressure in the pressurized chamber 52K, or the level of the molten metal M. Stopping the supply of pressurized gas also stops the molten metal supply. Alternatively, the pressurized gas may be actively discharged from the pressurized chamber 52K to reduce the pressure in the pressurized chamber 52K and stop the molten metal supply, or pressurized gas may be supplied to the molten metal discharge unit 54 to stop the discharge of the molten metal M and stop the molten metal supply. These methods may also be used in combination as needed. Although compressed air may be used as the pressurized gas, it is preferable to use an inert gas such as nitrogen gas from the viewpoint of preventing oxidation of the molten metal M. It is also preferable to take measures to prevent the molten metal discharge portion 54 and the molten metal supply pipe 55 from stagnating and the molten metal temperature from decreasing.

[0025] While the molten metal supply unit 50 shown in FIG. 1 is configured to supply molten metal by supplying pressurized gas into a sealed molten metal storage furnace 51, the configuration is not limited thereto. For example, a cylinder with a built-in piston may be immersed in the molten metal in the molten metal storage furnace, and the molten metal may be discharged from the cylinder into a molten metal supply pipe by pressing the piston. In this case, the amount of molten metal supplied is adjusted by the pressing stroke of the piston. Alternatively, for example, the molten metal may be supplied by tilting the molten metal storage furnace to discharge the molten metal into the molten metal supply pipe. In this case, the amount of molten metal supplied is adjusted by the tilt angle and tilt time of the molten metal storage furnace. Alternatively, a separate melting furnace for producing molten metal may be provided, and the melting furnace and molten metal storage furnace may be connected by an openable connecting pipe, allowing the molten metal consumed by the supply from the melting furnace to be replenished in the molten metal storage furnace.

[0026] Here, in the molten metal supply section 50, the molten metal M passes through multiple paths, including the molten metal storage furnace 51, the molten metal discharge section 54, and the molten metal supply pipe 55, so there is a time lag between the start of the supply of pressurized gas and the start of supplying the molten metal to the injection sleeve 21. Similarly, there is a time lag between the stop of the supply of pressurized gas and the completion of supplying the molten metal to the injection sleeve 21. Therefore, when the forward movement of the plunger 22 starts to be initiated to perform injection filling after the supply of pressurized gas is stopped, a longer waiting time is provided to allow for variation in the time lag. This time lag becomes larger the longer the distance between the multiple paths, and the longer the molten metal supply pipe 55, which is located at the most downstream and to which the additional paths are added, the greater the time lag.

[0027] Therefore, the discrimination unit 60 constantly observes the inside of the molten metal supply pipe 55 through an observation window 56 provided in the molten metal supply pipe 55, determines that the cessation of the flow of the molten metal M in the molten metal supply pipe 55 means that the molten metal supply has been completed, and transfers this information to the injection control unit 40. Upon receiving the information from the discrimination unit 60, the injection control unit 40 starts the forward movement of the plunger 22 to inject and fill the molten metal M. This eliminates the time lag. Discrimination unit 60 is of a non-contact type to avoid thermal influence from the high-temperature molten metal, and is placed at a position away from injection device 20 and molten metal supply unit 50. The means for observing the inside of molten metal pipe 55 through observation window 56 is selected from the following two means as appropriate.

[0028] The first method involves providing a photographing device that photographs the inside of the hot water supply pipe 55 through the observation window 56 and determining whether hot water supply has been completed from the photographed image data. For example, a photographing device such as an infrared thermo camera that can photograph the temperature distribution as image data or a colorimeter that converts temperature differences into color differences and creates image data is used. Comparing an image of the high-temperature molten metal M flowing inside the hot water supply pipe 55 with an image of the inside of the hot water supply pipe 55, which is at a lower temperature than the molten metal M after the flow has stopped, makes it easy to determine whether hot water supply has been completed. Furthermore, known techniques can be used, such as quantifying the temperature difference between the image data to numerically manage the completion of hot water supply, or using a binarization method to set a threshold value for the image data to image-manage the completion of hot water supply. These techniques facilitate ease of operation, simplify the equipment, and provide versatility.

[0029] The second method is to provide a measuring device that measures the inside of the hot water supply pipe 55 through the observation window 56, and determine the completion of hot water supply from the measured numerical data. For example, a laser displacement meter is used that can measure the surface height of the molten metal M flowing inside the hot water supply pipe 55. The point at which the surface height of the molten metal reaches zero can be clearly determined as the completion of hot water supply. Also, a luminance meter can be used to quantify the difference in brightness between the molten metal M and the hot water supply pipe 55, making it possible to determine the completion of hot water supply numerically. In this case, well-known technology can be used.

[0030] [First embodiment: injection filling method] Next, the injection filling method for casting using the die-casting machine shown in Fig. 1 will be explained using Fig. 2. The explanation will be given assuming that casting begins when preparatory steps such as cleaning the fixed die 11, movable die 12, and plunger 22 and applying a release agent and lubricant have been completed, and the die cavity 13 has been formed by clamping the casting die 10.

[0031] First, the molten metal supply unit 50 is operated to supply molten metal to the injection sleeve 21. Specifically, based on a control command from the pressurized gas control unit 53, pressure-adjusted nitrogen gas is supplied as the pressurized gas from the pressurized gas supply unit 52 to the pressurized chamber 52K in the molten metal storage furnace 51. The supply of pressurized gas pressurizes the molten metal M in the molten metal storage furnace 51 and discharges it to the molten metal discharge unit 54. At this time, the molten metal M discharge amount is adjusted by adjusting the molten metal surface height H of the molten metal M in the molten metal storage furnace 51. When the molten metal surface height H reaches a set value HM (H = HM), the supply of pressurized gas is stopped, and the pressurized gas is discharged from the pressurized chamber 52K to reduce the pressure in the pressurized chamber 52K and stop the discharge of the molten metal M. The set value HM is the discharge amount of the molten metal M and is set as the amount of molten metal supplied to the injection sleeve 21.

[0032] Here, the molten metal M flows from the molten metal storage furnace 51 to the molten metal discharge section 54, from the molten metal discharge section 54 to the molten metal supply pipe 55, and then flows through the molten metal supply pipe 55 and is supplied from the molten metal supply pipe 55 through the pouring port 24 into the injection sleeve 21. In other words, there is a time lag between the start of the pressurized gas supply and the start of molten metal supply to the injection sleeve 21. This suggests that there is also a time lag when molten metal supply to the injection sleeve 21 is completed. Even if the supply of pressurized gas from the pressurized gas supply section 52 is stopped, the completion of molten metal supply to the injection sleeve 21 is delayed by the time lag. Furthermore, it is difficult to adjust the molten metal surface height H of the molten metal M by adjusting the supply of pressurized gas, which causes fluctuations in the discharge rate of the molten metal M and the amount of molten metal supplied. These factors make it more difficult to adjust the timing at which the plunger 22 starts moving forward. Furthermore, the temperature of the molten metal M in the injection sleeve 21 fluctuates, making it extremely difficult to stabilize casting quality.

[0033] Therefore, the time lag can be eliminated by operating the discriminator 60 to accurately determine the completion of molten metal supply to the injection sleeve 21. Eliminating the time lag stabilizes the forward movement of the plunger 22 and the temperature of the molten metal in the injection sleeve 21. As a result, stable casting quality can be achieved. Specifically, the discriminator 60 begins operation upon the start of discharge of the molten metal M by the molten metal discharge unit 54. For example, in a discriminator 60 using an infrared thermo camera capable of capturing temperature distribution images as the imaging means, the completion of molten metal supply can be determined when the image data of the high-temperature molten metal M changes to the image data of the molten metal supply pipe 55, which has a lower temperature. Furthermore, in a discriminator 60 using a laser displacement meter capable of measuring the change in distance to a measurement object as the measurement means, the completion of molten metal supply can be easily determined because the distance to the surface of the molten metal M flowing inside the molten metal supply pipe 55 is different from the distance to the inner wall of the molten metal supply pipe 55. The determination result of the determination unit 60 that the supply of molten metal has been completed is transferred to the injection control unit 40, which starts the forward movement of the plunger 22 to inject and fill the molten metal M.

[0034] In this way, the injection filling method for a die casting machine equipped with a pressurized molten metal supply unit and a discrimination unit as shown in Figures 1 and 2 can accurately detect the completion of molten metal supply to the injection sleeve and stabilize the molten metal temperature inside the injection sleeve, thereby providing stable production of high-quality castings. Furthermore, it can utilize known equipment, satisfying all of the following: simplicity, cost reduction, and ease of maintenance.

[0035] [Second embodiment: die casting machine] Next, a die-casting machine according to a second embodiment will be described with reference to Fig. 3. Descriptions of parts that overlap with those of the first embodiment will be omitted, and only the hot water supply section 70, which is different from the first embodiment, will be described in detail.

[0036] The molten metal supply section 70 includes a molten metal storage furnace 71 with an open top, a molten metal discharge section 72 that discharges molten metal M from the molten metal storage furnace 71, and a discharge control section 73 that controls the operation of the molten metal discharge section 72. The discharge control section 73 is connected to the injection control section 40, and the operations of the injection device 20 and the molten metal supply section 70 are adjusted by the injection control section 40. The molten metal discharge section 72 is equipped with a multi-joint arm 74 that can freely rotate, tilt, rise, fall, traverse, and travel, and is equipped with a ladle 75 at the tip of the multi-joint arm 74 that can draw up a predetermined amount of molten metal M from the molten metal storage furnace 71 and transport the molten metal M in the direction of the injection sleeve 21 of the injection device 20.

[0037] Here, if there is an obstacle within the operating range of the ladle 75 and the molten metal M cannot be directly transported to the injection sleeve 21, or if the ladle 75 is located too far away for the injection sleeve 21 to reach, the following measures may be taken. For example, an intermediate vessel 76 equipped with a molten metal supply pipe 77 may be placed at an intermediate position, and the molten metal may be supplied from the molten metal storage furnace 71 to the ladle 75, from the ladle 75 to the intermediate vessel 76, and from the intermediate vessel 76 via the molten metal supply pipe 77 to the injection sleeve 21. The molten metal supply pipe 77 may also be provided with an observation window 78 through which the interior can be observed. It is preferable to take measures to prevent the molten metal from stagnating in the ladle 75, the intermediate vessel 76, and the molten metal supply pipe 77 and to prevent a drop in the molten metal temperature.

[0038] [Second embodiment: injection filling method] Next, an injection filling method for performing casting using the die-casting machine shown in Fig. 3 will be described with reference to Fig. 4. As in the first embodiment, the casting will be described assuming that the casting starts after the preparation step and the formation of the mold cavity 13 have been completed.

[0039] First, the molten metal supply unit 70 is operated to supply molten metal to the injection sleeve 21. Specifically, based on a control command from the discharge control unit 73, the molten metal discharge unit 72 is operated to pump molten metal M from the molten metal holding furnace 71 with the ladle 75. The ladle 75 is then moved and tilted at the position of the relay container 76, and the molten metal M is discharged from the ladle 75 into the relay container 76. The amount of molten metal M pumped up, i.e., the amount of molten metal supplied, is adjusted by adjusting the position of the ladle 75. The molten metal M discharged into the relay container 76 flows through the molten metal supply pipe 77 and is supplied to the injection sleeve 21 from the pouring port 24. After the molten metal M has been discharged into the relay container 76, the ladle 75 moves to its standby position.

[0040] Here, the molten metal M flows from the molten metal holding furnace 71 to the ladle 75, from the ladle 75 to the relay vessel 76, from the relay vessel 76 to the molten metal supply pipe 77, and then flows through the molten metal supply pipe 77 and passes from the molten metal supply pipe 77 through the pouring port 24 to be supplied to the injection sleeve 21. In other words, there is a time lag between when the ladle 75 draws up the molten metal M and when it starts to be supplied to the injection sleeve 21. This suggests that there is also a time lag when the molten metal supply to the injection sleeve 21 is completed. Even if the molten metal discharge part 72 is operated to tilt the ladle 75 and complete the discharge of the molten metal M, the molten metal M is still flowing through the relay vessel 76 or the molten metal supply pipe 77, and the completion of the molten metal supply to the injection sleeve 21 is delayed by the time lag. Furthermore, it is difficult to adjust the amount of molten metal M pumped up by adjusting the position of the ladle 75, and the amount of molten metal M supplied to the injection sleeve 21 fluctuates due to leakage of the molten metal M when the ladle 75 moves or tilts. These factors make it more difficult to adjust the timing at which the plunger 22 starts moving forward, and furthermore, the temperature of the molten metal M in the injection sleeve 21 fluctuates, making it very difficult to stabilize the casting quality.

[0041] Therefore, the time lag can be eliminated by operating the discriminator 60 to accurately determine the completion of molten metal supply to the injection sleeve 21. Eliminating the time lag stabilizes the forward movement of the plunger 22 and the temperature of the molten metal in the injection sleeve 21. As a result, stable casting quality can be achieved. Specifically, the discriminator 60 begins operation upon receipt of the start of discharge of the molten metal M into the relay vessel 76 by the molten metal discharge unit 72. For example, the discriminator 60 employs a color difference meter as the imaging means, identifies the temperature difference between the molten metal M and the molten metal supply pipe 77 as a color difference value, and determines that the molten metal supply to the injection sleeve 21 has been completed by confirming the cessation of the flow of the molten metal M in the molten metal supply pipe 77 from a change in the color difference value. Furthermore, for example, the discriminator 60 employs a radiation thermometer as a measuring means, measures the temperature difference between the molten metal M and the molten metal supply pipe 77, and determines that the molten metal supply to the injection sleeve 21 has been completed by confirming the cessation of the flow of the molten metal M in the molten metal supply pipe 77 from a temperature change. The determination result of the determination unit 60 that the supply of molten metal has been completed is transferred to the injection control unit 40, which starts the forward movement of the plunger 22 to inject and fill the molten metal M.

[0042] In this way, the injection filling method for a die casting machine equipped with a ladle-type molten metal supply unit and a discrimination unit as shown in Figures 3 and 4 can accurately detect the completion of molten metal supply to the injection sleeve and stabilize the molten metal temperature inside the injection sleeve, thereby providing stable production of high-quality castings. Furthermore, it can utilize known equipment, and is simple, cost-effective, and easy to maintain.

[0043] 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]

[0044] 10 Casting mold 11 Fixed mold 12 Movable mold 13 Mold cavity 20 Injection device 21 Injection sleeve 22 Plunger 23 Rod 24 Pouring spout 30 Injection drive unit 40 Injection control unit 50, 70 hot water supply unit 51, 71 Molten metal holding furnace 52 Pressurized gas supply unit 52K pressure chamber 53 Pressurized gas control section 54, 72 Molten metal discharge section 55, 77 Hot water pipes 56, 78 Observation window 60 Discrimination part 73 Emission control section 74 Articulated Arm 75 Ladle 76 Relay container 100, 200 die casting machine F forward B Back BE standby position FE injection completion position M molten metal H Water level height HM setting value

Claims

1. In a die-casting machine injection filling method, molten metal supplied into an injection sleeve is injected and filled into a mold cavity by the forward movement of a plunger, a melt supply unit that supplies molten metal to the injection sleeve; and a determination unit that determines whether melt supply to the injection sleeve has been completed, the molten metal supply unit includes a molten metal supply pipe that causes the molten metal to flow toward the pouring port of the injection sleeve, and an observation window that is provided in the molten metal supply pipe; the discrimination unit includes an imaging means for imaging the inside through the observation window, or a measuring means for measuring the inside through the observation window, The determination unit determines whether the hot water supply is complete based on the image data of the photographing means or the measurement data of the measuring means, The injection filling method for a die casting machine is characterized in that the forward movement of the plunger is started based on the discrimination signal from the discrimination unit.

2. 2. The injection filling method for a die casting machine according to claim 1, wherein the molten metal supply section discharges a predetermined amount of molten metal from a molten metal holding furnace using a pressurizing means, and supplies the molten metal discharged via the molten metal supply pipe to the injection sleeve.

3. 2. The injection filling method for a die casting machine according to claim 1, wherein the molten metal supply section draws up a predetermined amount of molten metal from a molten metal holding furnace using a ladle and supplies the molten metal drawn up via the molten metal supply pipe to the injection sleeve.

4. In a die casting machine, the molten metal supplied to the injection sleeve is injected and filled into the mold cavity by the forward movement of the plunger. a melt supply unit that supplies molten metal to the injection sleeve; and a determination unit that determines whether melt supply to the injection sleeve has been completed, the molten metal supply unit includes a molten metal supply pipe that causes the molten metal to flow toward the pouring port of the injection sleeve, and an observation window that is provided in the molten metal supply pipe; the discrimination unit includes an imaging means for imaging the inside through the observation window, or a measuring means for measuring the inside through the observation window, The determination unit determines whether the hot water supply is complete based on the image data of the photographing means or the measurement data of the measuring means, The die casting machine is characterized in that the forward movement of the plunger is started based on the discrimination signal from the discrimination unit.

Images