Vacuum die casting apparatus

Abstract

To eliminate clogging more quickly than before when clogging occurs in vacuum piping provided with a filter.SOLUTION: The vacuum pipe 20 communicates with the cavity 57. A cavity 57 is formed by closing the movable mold 60 and the fixed mold 50. The vacuum pump 29 is connected to the vacuum pipe 20. Filters 21,23,25 are arranged in multiple stages in the vacuum pipe 20. A vacuum pump 29 is connected to the distal end of the vacuum line 20. The purge pipe 28 is connected to the distal end. A compressor 30 is connected to the purge pipe 28. Further, a flow rate sensor 22,24,26 or a pressure sensor 122,124,126 is disposed in the vacuum pipe 20. The flow sensor 222426 or the pressure sensor 122124126 is arranged for each of the sections 20A, 20B, and 20C partitioned by the multistage filters 212325.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] Disclosed herein is a vacuum die casting apparatus.

[0002] Patent Documents 1 and 2 disclose vacuum die casting machines. In Patent Document 1, a filter is provided in the vacuum pipe. In Patent Document 2, an auxiliary path branches off from the vacuum pipe. An air blow device is connected to the auxiliary path. In the preparation stage between shots, the vacuum pipe is air-blow cleaned. The air-blow cleaning discharges the molten metal from inside the vacuum pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] China Utility Model Registration No. 215392378 [Patent Document 2] Japanese Patent Publication No. 2022-141115 Summary of the Invention [Problem to be solved by the invention]

[0004] This specification discloses a vacuum die casting apparatus that, when a blockage occurs in a vacuum pipe equipped with a filter, can clear the blockage more quickly than conventional methods. [Means for solving the problem]

[0005] This specification discloses a vacuum die casting apparatus. The apparatus includes a vacuum pipe and a vacuum pump. The vacuum pipe is in communication with a cavity. The movable mold and the fixed mold are closed to form the cavity. The vacuum pump is connected to the vacuum pipe. Multiple stages of filters are arranged within the vacuum pipe. The vacuum pump is connected to the distal end of the vacuum pipe. A purge pipe is connected to the distal end. A compressor is connected to the purge pipe. Furthermore, a flow sensor or a pressure sensor is arranged in the vacuum pipe. The flow sensor or pressure sensor is arranged in each section separated by the multiple stages of filters.

[0006] According to the above configuration, it is possible to detect in which section a blockage has occurred, and the blockage in the vacuum pipe can be quickly cleared.

[0007] In the above configuration, a drain pipe may be connected to a section of the vacuum pipe between the filter closest to the cavity among the multi-stage filters and the cavity.

[0008] According to the above configuration, when the vacuum pipe is purged with the vacuum source, residue in the vacuum pipe is discharged through the drain pipe, which prevents the residue from entering the cavity.

[0009] In the above configuration, a vacuum valve may be provided in the vacuum pipe closer to the drain pipe. The closer the vacuum valve is to the cavity, the closer the vacuum pipe is to the cavity. After the vacuum valve is closed, the vacuum pipe is purged by the compressor.

[0010] According to the above configuration, the vacuum valve blocks the flow path between the vacuum pipe and the cavity, thereby preventing residue from flowing into the cavity.

[0011] In the above configuration, the vacuum die casting machine may include a controller. The controller acquires flow rate values ​​from the plurality of flow rate sensors. The controller includes a processor. The processor acquires flow rate values ​​during a purge period of the vacuum pipe. The processor determines a section during the purge period in which the decrease in the flow rate value exceeds a threshold value as a blocked section.

[0012] According to the above configuration, the pressure loss of the filter during the purging period is calculated, and the clogged state of the filter can be accurately determined.

[0013] In the above configuration, the multi-stage filters may have different mesh sizes. When the blocked section spans multiple sections, the processor determines that the distal filter in the blocked section closest to the compressor is the blocked filter.

[0014] According to the above configuration, it is possible to identify the filter to be replaced from among different types of filters. [Effects of the Invention]

[0015] According to the vacuum die casting apparatus disclosed in this specification, when a blockage occurs in a vacuum pipe equipped with a filter, the blockage can be cleared more quickly than conventional methods. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram illustrating a vacuum die-casting apparatus (flow rate sensor installed type) according to an embodiment of the present invention. [Figure 2] FIG. 10 is a diagram illustrating a vacuum piping purge flow when the measured value is a flow rate value. [Figure 3] FIG. 1 is a diagram (1 / 3) illustrating the molding process. [Figure 4] FIG. 2 is a diagram (2 / 3) illustrating the molding process. [Figure 5] FIG. 3 is a diagram (3 / 3) illustrating the molding process. [Figure 6] 1 is a diagram illustrating a vacuum die-casting apparatus (pressure sensor installed type) according to an embodiment of the present invention. [Figure 7] FIG. 10 is a diagram illustrating a vacuum piping purge flow when the measured value is a pressure value. DETAILED DESCRIPTION OF THE INVENTION

[0017] 1. Equipment overview 1 illustrates a vacuum die-casting apparatus 100 according to this embodiment. The vacuum die-casting apparatus 100 includes a controller 10, a vacuum pipe 20, a vacuum pump 29, a fixed mold 50, and a movable mold 60.

[0018] As shown in Fig. 3, the fixed mold 50 and the movable mold 60 are clamped together. When the fixed mold 50 and the movable mold 60 are closed, a gate 55 and a cavity 57 are formed between the fixed mold 50 and the movable mold 60. The clamping force is, for example, 4000 tons or more. Based on this clamping force, the vacuum die casting apparatus 100 is also called a megacast machine or a gigacast machine.

[0019] 2.Vacuum piping Referring to FIG. 1 , the vacuum pipe 20 communicates with the cavity 57. For example, the vacuum pipe 20 is connected to the fixed mold 50. Hereinafter, the terms proximal side and distal side are used to describe sections of the vacuum pipe 20. The proximal side refers to the side relatively closer to the cavity 57. The distal side refers to the side relatively farther from the cavity 57. The cavity 57 is connected to the proximal end of the vacuum pipe 20. The vacuum pump 29 is connected to the distal end of the vacuum pipe 20. For example, the vacuum pump 29 is an oil rotary vacuum pump.

[0020] The vacuum pipe 20 is provided with, in order from the proximal end to the distal end, a vacuum valve V1, a drain pipe 27, a mesh filter 21, a mist separator 23, a strainer 25, a purge pipe 28, a vacuum valve V4, and a vacuum pump 29. The drain pipe 27 is also provided with a bypass valve V2. The purge pipe 28 is also provided with a bypass valve V3.

[0021] The drain pipe 27 is provided between the mesh filter 21 and the cavity 57. That is, the drain pipe 27 is connected to the first section 20A of the vacuum pipe 20. In a purging process described later, residues in the vacuum pipe 20 are discharged from the drain pipe 27. By ensuring a discharge destination for the residues, the intrusion of the residues into the cavity 57 is suppressed.

[0022] A vacuum valve V1 is provided in the vacuum pipe 20, closer to the cavity 57 than the drain pipe 27. In the purging process described below, the vacuum valve V1 is closed, and then the vacuum pipe 20 is purged by the compressor 30. By closing the vacuum valve V1 during purging, the intrusion of residue into the cavity 57 is suppressed.

[0023] The purge pipe 28 is connected to the distal end of the vacuum pipe 20. Furthermore, a compressor 30 is connected to the distal end of the purge pipe 28.

[0024] The vacuum valves V1, V4 and the bypass valves V2, V3 are, for example, solenoid valves. As will be described later, the vacuum valves V1, V4 and the bypass valves V2, V3 are controlled to open and close by a controller 10.

[0025] The vacuum pipe 20 is provided with multiple filters. Specifically, from the proximal end to the distal end, a mesh filter 21, a mist separator 23, and a strainer 25 are provided in the vacuum pipe 20. These three filters have different mesh sizes. Of the three filters, the mesh filter 21 has the coarsest mesh. Of the three filters, the strainer 25 has the finest mesh.

[0026] During the evacuation process, molten metal 59 (see FIG. 4) in cavity 57 may be drawn into vacuum pipe 20. The drawn molten metal 59 is cooled and solidified in vacuum pipe 20. Mesh filter 21 captures the solidified metal chips (residue). Due to this function, mesh filter 21 has higher strength than mist separator 23 and strainer 25.

[0027] The mist separator 23 separates the liquid from the gas-liquid mixture that has passed through the mesh filter 21. Furthermore, the strainer 25 captures fine dust that the mesh filter 21 and the mist separator 23 have been unable to capture.

[0028] The vacuum pipe 20 is divided into multiple sections by the mesh filter 21, the mist separator 23, and the strainer 25. Referring to Fig. 1, the section from the vacuum valve V1 to the mesh filter 21 is the first section 20A. The section from the mesh filter 21 to the mist separator 23 is the second section 20B. The section from the mist separator 23 to the strainer 25 is the third section 20C. Furthermore, the section from the strainer 25 to the vacuum pump 29 is the fourth section 20D.

[0029] Furthermore, a flow rate sensor is provided for each section. A flow rate sensor 22 is provided in the first section 20A. A flow rate sensor 24 is provided in the second section 20B. A flow rate sensor 26 is provided in the third section 20C. For example, the flow rate sensors 22, 24, and 26 take the flow direction during purging as positive. In other words, the flow direction from the compressor 30 toward the drain pipe 27 is taken as a positive value for the flow rate sensors 22, 24, and 26.

[0030] It is not necessary to provide a flow rate sensor in all sections separated by filters, for example, the fourth section 20D, which is the most distal section, may not be provided with a flow rate sensor.

[0031] 3. Controller 1, the controller 10 is connected to a display unit 16 and an input device 17. The display unit 16 may be a display device, and the input device 17 may be an input device such as a keyboard or a mouse.

[0032] The controller 10 is configured by, for example, a computer. That is, the controller 10 includes a CPU 11, a RAM 12, a ROM 13, a storage 14, and an input / output controller 15.

[0033] The CPU 11 is a central processing unit, also called a processor. The RAM 12 is a volatile storage device that temporarily stores data during operation. The ROM 13 is a storage device from which data can be read. The storage 14 is a storage device from which data can be written and read. The storage 14 is configured, for example, by an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0034] By executing the program stored in the storage 14 or the ROM 13, the CPU 11 can execute the vacuum piping purge flow illustrated in FIG.

[0035] When performing the vacuum piping purge flow, the CPU 11 acquires flow rate values ​​from the flow rate sensors 22, 24, and 26. The CPU 11 also controls the opening and closing of the vacuum valves V1 and V4 and the bypass valves V2 and V3. The CPU 11 also controls the driving of the vacuum pump 29 and the compressor 30.

[0036] The controller 10 may also perform overall control of the vacuum die casting apparatus 100. For example, the controller 10 controls the advancement and retreat of the movable die 60 and the piston 58. The vacuum die casting apparatus 100 is also provided with a ladle (not shown) as a device for injecting molten metal into the sprue 56A of the sleeve 56. The controller 10 controls the operation of this ladle. Furthermore, cooling channels (not shown) are formed within the fixed die 50 and the movable die 60. The controller 10 controls the flow rate of cooling water flowing through the cooling channels.

[0037] 4. Vacuum piping purge flow Figure 2 shows an example of a vacuum pipe purge flow. In the vacuum pipe purge flow, compressed air (scavenging air) is blown into the vacuum pipe 20 in the direction opposite to the direction of evacuation. The vacuum pipe purge flow is incorporated into a part of the molding process. In the following, among the molding processes, steps related to the vacuum pipe purge flow will be shown as appropriate.

[0038] 3, the movable mold 60 moves toward the fixed mold 50, and both molds are clamped together. When clamping is complete, the vacuum piping purge flow (see FIG. 2) is activated.

[0039] The CPU 11 opens the vacuum valves V1 and V4 (S10). At this time, the bypass valves V2 and V3 are closed in the vacuum piping purge flow in the previous shot.

[0040] The CPU 11 drives the vacuum pump 29 (S12). This causes the air to be drawn out from the cavity 57 (see FIG. 3). By drawing out the air from the cavity 57, the occurrence of porosity is suppressed in the molded product 70 (see FIG. 5).

[0041] For example, as the air in cavity 57 is removed, the flow rate values ​​detected by flow rate sensors 22, 24, and 26 decrease. When the flow rate value of any of flow rate sensors 22, 24, and 26 falls below a predetermined threshold, CPU 11 stops vacuum pump 29. This threshold is also called a vacuum determination value.

[0042] After the vacuum pump 29 has stopped, the CPU 11 closes the vacuum valves V1 and V4 (S14). In step S20, which will be described later, purging is performed by the compressor 30. Prior to this purging, in step S14, the vacuum valves V1 and V4 are closed. That is, when residues in the vacuum pipe 20 are discharged by purging, the discharge destination is prevented from becoming the cavity 57.

[0043] Once the evacuation of the cavity 57 is complete, molten metal is poured into the sleeve 56 through the gate 56A. Referring further to FIG. 4, the molten metal 59 is injected into the gate 55 and the cavity 57 at high speed and pressure by the piston 58. Furthermore, cooling water is supplied to a cooling channel (not shown). The molten metal 59 is cooled within the gate 55 and the cavity 57, thereby obtaining a molded product 70, as illustrated in FIG. 5.

[0044] The molded article 70 is removed from the fixed mold 50 and the movable mold 60 by a robot (not shown). When removal of the molded article 70 is completed, the CPU 11 receives a removal completion notification (S16). Next, the CPU 11 opens the bypass valves V2 and V3 (S18). With the opening of the bypass valves V2 and V3, a purge path (scavenging path) that runs from the compressor 30 through the vacuum pipe 20 to the drain pipe 27 is opened.

[0045] The CPU 11 drives the compressor 30 to send compressed air into the vacuum pipe 20. At this time, the CPU 11 sets the purge pressure Pp of the compressor 30 to a predetermined initial value P0 (S20).

[0046] Furthermore, the CPU 11 acquires flow rate values ​​of the flow rate sensors 22, 24, and 26 during the purge period (S22). When there are no impurities such as residue in the vacuum pipe 20, the end of the purge path is opened by the drain pipe 27, and the flow rate based on the purge pressure Pp is maintained. On the other hand, when residue such as aluminum chips is present in the vacuum pipe 20 and is caught in the mesh filter 21, the mist separator 23, or the strainer 25, the purge path is blocked. As the purge path is blocked, the flow rate in the vacuum pipe 20 decreases.

[0047] The CPU 11 determines whether the vacuum pipe 20 is clogged based on the change in flow rate. That is, the CPU 11 calculates the difference ΔQs between the flow rate value at the beginning of the purge period (initial flow rate value) of each of the flow rate sensors 22, 24, 26 and the flow rate value after a predetermined time has elapsed. The predetermined time is set, for example, between 5 and 60 seconds.

[0048] The difference ΔQs indicates the amount of decrease in the flow rate value from the beginning of the purge. The CPU 11 determines whether or not the difference ΔQs of each of the flow rate sensors 22, 24, 26 exceeds a threshold value Qth (S24). The threshold value Qth is also called a blockage determination value.

[0049] If both the differences ΔQs are equal to or smaller than the threshold value Qth, the CPU 11 outputs a normal completion signal to the display unit 16 (S26). In other words, the display unit 16 indicates that the vacuum pipe 20 is open. In response to this, the operator of the vacuum die casting apparatus 100 starts the next shot.

[0050] On the other hand, if any of the differences ΔQs exceeds the threshold Qth, it means that the flow rate value has decreased significantly since the beginning of the purge. The CPU 11 identifies the flow rate sensor 22, 24, 26 that measured the difference ΔQs that exceeded the threshold Qth. Furthermore, the CPU 11 determines that the section (first section 20A-third section 20C) in which the identified flow rate sensor 22, 24, 26 is installed is a blocked section.

[0051] Next, the CPU 11 increases the purge pressure Pp from its current value (S28). This increase ΔPp is, for example, a fixed value. By increasing the purge pressure Pp, the pressurized air (scavenging air) blows away any residue trapped in any of the filters.

[0052] The CPU 11 determines whether the increased purge pressure Pp exceeds a threshold value Pp_th (S30). Since an excessive increase in purge pressure can damage the filter, an upper limit value (threshold value Pp_th) of the purge pressure is set.

[0053] If the increased purge pressure Pp is less than the threshold value Pp_th, the flow returns to step S22. If the increased purge pressure Pp exceeds the threshold value Pp_th, the flow proceeds to error processing.

[0054] Referring to FIG. 1, in error processing, the CPU 11 determines whether any of the first section 20A to the third section 20C is a blocked section. For example, multiple sections may be determined to be blocked sections. If a specific section is blocked, air will not flow in the sections downstream from that section. For example, if the second section 20B is blocked, the first section 20A downstream (proximal side) thereof will also be blocked.

[0055] The CPU 11 identifies the most distal blocked section (S32). That is, the CPU 11 identifies the blocked section that is closest to the compressor 30. The identified blocked section is also referred to as the most distal blocked section.

[0056] Furthermore, the CPU 11 determines that the filter on the distal side in the identified blocked section is a clogged filter (S34). That is, the CPU 11 determines that the filter on the side closer to the compressor 30 in the blocked section is a clogged filter. The CPU 11 displays the determined type of clogged filter on the display unit 16 (S36). That is, the operator of the vacuum die casting apparatus 100 is notified of the filter to be replaced.

[0057] As described above, the vacuum pipe 20 is provided with the mesh filter 21, the mist separator 23, and the strainer 25. These filters are all different types. For example, the mesh size of each filter is different. By identifying the clogged filter, it is possible to narrow down the filters to be replaced.

[0058] In this way, in the vacuum die casting apparatus 100 according to this embodiment, the vacuum pipe 20 is divided into a plurality of sections by multi-stage filters. A flow rate sensor is provided for each section. This makes it possible to identify which section is clogged. In other words, it is possible to identify which filter among the multi-stage filters is the clogged filter.

[0059] 5. Pressure Sensor In the above-described embodiment, a flow rate sensor was provided in the vacuum pipe 20. However, the vacuum die casting apparatus 100 according to this embodiment is not limited to this configuration. For example, instead of a flow rate sensor, a pressure sensor may be provided in each section of the vacuum pipe 20. For example, referring to FIG. 6, a pressure sensor 122 is provided in the second section 20B. A pressure sensor 124 is provided in the third section 20C. A pressure sensor 126 is provided in the fourth section 20D. A pressure sensor need not be provided in the first section 20A.

[0060] The vacuum piping purge flow when the pressure sensors 122, 124, and 126 are disposed in the vacuum die casting apparatus 100 is illustrated in FIG. 7. In FIG. 7, step S24 in FIG. 2 is replaced with step S124. Also, step S34 is replaced with step S134. The remaining steps are the same as those in FIG. 2.

[0061] In step S124, a pressure difference ΔPs is calculated. The difference ΔPs is the difference between the pressure value at the beginning of the purge (initial pressure value) and the pressure value after a predetermined time has elapsed. The absolute value of the difference |ΔPs| is then compared with a threshold value Pth. This difference |ΔPs| indicates the amount of increase in the pressure value from the beginning of the purge.

[0062] When there are no impurities such as residues in the vacuum pipe 20, the end of the purge path is opened by the drain pipe 27, so that the purge pressure Pp is maintained at a constant pressure.

[0063] On the other hand, if residue such as aluminum chips is present in the vacuum pipe 20 and gets caught in the mesh filter 21, the mist separator 23, or the strainer 25, the purge path will be blocked. As the purge path is blocked, the pressure inside the vacuum pipe 20 increases.

[0064] The CPU 11 determines whether the vacuum pipe 20 is blocked based on a pressure change. That is, the CPU 11 calculates the difference ΔPs between the pressure value at the start of purging (initial pressure value) and the pressure value after a predetermined time has elapsed, for each of the pressure sensors 122, 124, and 126. Furthermore, the CPU 11 determines whether the absolute value |Ps| of each difference ΔPs for the pressure sensors 122, 124, and 126 exceeds a threshold value Pth (blockage determination value) (S124).

[0065] If any of the differences |ΔPs| is equal to or less than the threshold value Pth, the CPU 11 outputs a normal completion signal to the display unit 16 (S16). On the other hand, if any of the differences ΔPs exceeds the threshold value Pth, the CPU 11 determines that the section (second section 20B-fourth section 20D) in which the pressure sensor 122, 124, 126 that measured that difference ΔPs is installed is a blocked section.

[0066] When any of the mesh filter 21, the mist separator 23, and the strainer 25 becomes clogged, the pressure in the section distal to (in other words, upstream of) the clogged filter increases.

[0067] If there are multiple blocked sections, the CPU 11 identifies the most proximal blocked section (S132). That is, the CPU 11 identifies the blocked section that is farthest from the compressor 30. The identified blocked section is also referred to as the most proximal blocked section.

[0068] Furthermore, the CPU 11 determines that the filter on the proximal side in the most proximal blocked section is the clogged filter (S134). That is, the CPU 11 determines that the filter on the side farthest from the compressor 30 (downstream side) in the blocked section is the clogged filter. The CPU 11 displays the determined type of clogged filter on the display unit 16 (S36). That is, the operator of the vacuum die casting apparatus 100 is notified of the filter to be replaced. [Explanation of symbols]

[0069] 10 Controller, 11 CPU (processor), 20 Vacuum piping, 20A First section, 20B Second section, 20C Third section, 20D Fourth section, 21 Mesh filter, 22, 24, 26 Flow sensor, 23 Mist separator, 25 Strainer, 27 Drain piping, 28 Purge piping, 29 Vacuum pump, 30 Compressor, 50 Fixed mold, 57 Cavity, 60 Movable mold, 70 Molded product, 100 Vacuum die casting device, 122, 124, 126 Pressure sensor, V1, V4 Vacuum valve, V2, V3 Bypass valve.

Claims

1. a vacuum pipe communicating with a cavity formed by closing the movable mold and the fixed mold; a vacuum pump connected to the vacuum pipe; A vacuum die casting apparatus comprising: A filter is arranged in multiple stages in the vacuum pipe, a purge pipe is connected to the vacuum pipe at a distal end to which the vacuum pump is connected; A compressor is connected to the purge pipe, Furthermore, a flow rate sensor or a pressure sensor is disposed in each section of the vacuum piping separated by the multi-stage filters. Vacuum die casting equipment.

2. 2. The vacuum die casting apparatus according to claim 1, a drain pipe is connected to a section of the vacuum pipe between the filter closest to the cavity among the multi-stage filters and the cavity; Vacuum die casting equipment.

3. 3. The vacuum die casting apparatus according to claim 2, a vacuum valve is provided in the vacuum pipe at a proximal side closer to the cavity than the drain pipe; After the vacuum valve is closed, the vacuum piping is purged by the compressor. Vacuum die casting equipment.

4. 4. The vacuum die casting apparatus according to claim 2 or 3, a controller that acquires flow values ​​from the plurality of flow sensors; the controller comprises a processor; The processor obtains the flow rate value during a purge period of the vacuum line; The processor determines the section in which the amount of decrease in the flow rate value during the purge period exceeds a threshold to be a blocked section. Vacuum die casting equipment.

5. 5. The vacuum die casting apparatus according to claim 4, The multi-stage filters have different mesh sizes. When the blocked section includes a plurality of sections, the processor determines that the filter on the distal side of the blocked section closest to the compressor is the blocked filter. Vacuum die casting equipment.

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