Die cast facility and method for manufacturing casting

Abstract

To provide a die cast facility which enables reduction in verification of product quality.SOLUTION: This die cast facility comprises: a control device that switches the moving speed of a piston from a predetermined low speed to a predetermined high speed at the predetermined stroke position of the piston; and a measurement device that measures the weight of a ladle in a state where a molten metal is scooped up from a molten metal furnace and the weight of the ladle after the molten metal is poured from the ladle to an injection sleeve. The control device includes: a calculation unit that calculates the weight of the molten metal poured to the injection sleeve by subtracting the weight of the ladle after the molten metal is poured from the weight of the ladle in the state where the molten metal is scooped up; and a correction unit that corrects the stroke position of the piston on the basis of the weight of the molten metal poured to the injection sleeve.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Patent Document 1 discloses a die casting facility consisting of a mold, a vacuum device for creating a vacuum in the cavity inside the mold, a sleeve facing the gate portion of the cavity, a ladle for injecting molten metal into the sleeve, a plunger for pushing out the molten metal, and a holding furnace for storing the molten metal while keeping it warm.

[0003] Patent Document 2 discloses that the temperature of the molten aluminum material is set to 700°C to 740°C, and when the bath molten metal is poured into a mold, the pouring speed at the gate is set to 0.3 to 0.6 m / s (low speed) for about half of the initial amount poured, and then the inside of the mold is evacuated to 200 Torr or less, while the remaining 40% or more of the bath molten metal is poured at a pouring speed of 10 m / sec (high speed), and the final small amount of molten metal is poured at a reduced speed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2000-52015 A [Patent Document 2] Japanese Patent Application Publication No. 4-172166 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional die casting equipment shown in Patent Document 1, the molten metal remaining inside the ladle solidifies or solidifies, changing the internal volume of the ladle and causing variations in the volume of the molten metal pumped up by the ladle. Also, in the conventional die casting equipment shown in Patent Document 2, the injection speed is switched from low to high at a predetermined stroke position of the piston (injection speed switching position), so when the amount of poured molten metal is small, the molten metal is injected into the cavity together with air, and when the amount of poured molten metal is large, the molten metal is injected into the cavity at a low speed, causing variations in product quality.

[0006] In view of the above circumstances, an object of at least one embodiment of the present invention is to provide a die casting apparatus and a manufacturing method for a casting that can reduce variation in product quality. [Means for solving the problem]

[0007] (1) A die casting facility according to at least one embodiment of the present invention is a die casting facility for injecting a molten metal pumped up from a molten metal furnace into a cavity provided in a mold, the die casting facility including a pouring device having a ladle for pumping up the molten metal from the molten metal furnace, an injection sleeve communicating with the cavity and into which the molten metal is poured from the ladle, and a piston movable within the injection sleeve and moving toward the cavity; and an injection device for changing the moving speed of the piston from a predetermined low speed to a predetermined high speed at a predetermined stroke position of the piston. the control device has a calculation unit that calculates the weight of the ladle after the molten metal has been poured from the ladle when it has been pumped up from the molten metal furnace, and a measurement unit that measures the weight of the ladle after the molten metal has been poured from the ladle into the injection sleeve, and the control device has a calculation unit that calculates the weight of the molten metal poured into the injection sleeve by subtracting the weight of the ladle after the molten metal has been poured from the weight of the ladle when it has pumped up the molten metal, and a correction unit that corrects the stroke position of the piston based on the weight of the molten metal poured into the injection sleeve.

[0008] According to the above configuration (1), the weight of the ladle after the molten metal has been poured is subtracted from the weight of the ladle in a state in which the molten metal has been pumped up to calculate the weight of the molten metal poured into the injection sleeve, and the predetermined stroke position of the piston, at which the piston moving speed is switched from a predetermined low speed to a high speed, is corrected based on this weight. In this way, the predetermined stroke position of the piston is corrected based on the weight of the molten metal poured into the injection sleeve, so that variation in product quality can be reduced.

[0009] (2) In some embodiments, in the configuration of (1) above, the measuring device is a load cell provided on a shaft that suspends the ladle.

[0010] According to the above configuration (2), a load cell provided on the shaft that suspends the ladle measures the weight of the ladle when it has pumped up the molten metal from the molten metal furnace and the weight of the ladle after the molten metal has been poured from the ladle into the injection sleeve. This makes it possible to accurately measure the weight of the ladle when it has pumped up the molten metal and the weight of the ladle after the molten metal has been poured.

[0011] (3) In some embodiments, in the configuration of (1) or (2) above, the correction unit calculates a stroke to correct the stroke position of the piston from the weight of the molten metal poured into the injection sleeve, the specific gravity of the molten metal, and the cross-sectional area of ​​the injection sleeve.

[0012] According to the above configuration (3), the stroke position of the piston can be corrected based on the weight of the molten metal poured into the injection sleeve, the specific gravity of the molten metal, and the cross-sectional area of ​​the injection sleeve.

[0013] (4) A manufacturing method for a casting according to at least one embodiment of the present invention is a manufacturing method for a casting, in which the moving speed of a piston that injects molten metal poured into an injection sleeve into a cavity formed in a mold is switched from a predetermined low speed to a predetermined high speed at a predetermined stroke position of the piston, and includes the steps of measuring the weight of the ladle after drawing up the molten metal, pouring the molten metal into an injection sleeve communicating with the cavity, measuring the weight of the ladle after the molten metal has been poured, calculating the weight of the molten metal poured into the injection sleeve by subtracting the weight of the ladle after the molten metal has been poured from the weight of the ladle in the state in which the molten metal has been drawn up, and correcting the predetermined stroke position of the piston based on the weight of the molten metal poured into the injection sleeve.

[0014] According to the manufacturing method of (4) above, the weight of the ladle after the molten metal has been poured is subtracted from the weight of the ladle when the molten metal has been pumped up to calculate the weight of the molten metal poured into the injection sleeve, and the predetermined stroke position of the piston is corrected based on this weight. In this way, the predetermined stroke position of the piston is corrected based on the weight of the molten metal poured into the injection sleeve, so that the variation in product quality can be reduced. Effect of the Invention

[0015] According to at least one embodiment of the present invention, it is possible to reduce variation in product quality. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a schematic diagram of a pouring device. [Diagram 2] FIG. 2 is a schematic diagram of the load cell shown in FIG. 1; [Figure 3-1] FIG. 2 is a schematic diagram of the injection device showing a state in which pouring of molten metal into the injection sleeve is completed; [Figure 3-2]FIG. 2 is a schematic diagram of a pouring device showing a state in which the molten metal has been filled up to a predetermined stroke position of the piston. [Figure 3-3] FIG. 2 is a schematic diagram of a pouring device showing a state in which molten metal has been injected into a cavity. [Figure 4] FIG. 2 is a block diagram showing a control configuration of the die casting equipment. [Diagram 5] 1 is a flowchart illustrating a manufacturing method of a casting. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of components described as the embodiments or shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0018] [Die casting equipment] The die casting equipment 1 according to the embodiment is a die casting equipment that injects a molten metal (e.g., an aluminum alloy) pumped up from a molten metal furnace into a cavity 61 provided in a die 6. The die casting equipment 1 includes a pouring device 2, an injection device 3, a control device 4, and a measurement device 5.

[0019] As shown in Fig. 1, the pouring device 2 is a device that draws up molten metal from a molten metal furnace and pours the molten metal into the injection device 3, and is composed of, for example, a six-axis robot. The pouring device 2 is equipped with a ladle 21 that draws up molten metal from the molten metal furnace. The ladle 21 is tiltable, and the tilt angle is controllable. By tilting the ladle 21 that has drawn up the molten metal, excess molten metal exceeding a predetermined amount can be returned to the molten metal furnace.

[0020] As shown in Figures 3-1 to 3-3, the injection device 3 is a device that injects the molten metal pumped up by the pouring device 2 into a cavity 61 provided in a mold 6, and includes an injection sleeve 31 that communicates with the cavity 61 and into which the molten metal is poured from a ladle 21, and a piston 32 that is movable within the injection sleeve 31 and moves toward the cavity 61. A pouring port 31a is provided in the injection sleeve 31, and the molten metal is poured from here (see Figure 3-1). A plunger tip 321 is provided at the tip of the piston 32 on the cavity 61 side.

[0021] The control device 4 is a device that switches the moving speed of the piston 32 from a predetermined low speed to a predetermined high speed at a predetermined stroke position SP (see FIG. 3-2) of the piston 32. The predetermined stroke position SP (switching position) is, for example, a position where the molten metal reaches a gate position provided immediately after (on the cavity 61 side) the mold parting surface (parting line) 62.

[0022] As shown in FIG. 3-1, in the injection device 3, the piston 32 is in a position where the pouring port 31a is opened (hereinafter referred to as the "pouring position"), and the movement speed of the piston 32 is set to a predetermined low speed from the pouring position to the switching position shown in FIG. 3-2. The process in which the piston 32 moves from the pouring position to the switching position, that is, the process in which the movement speed of the piston 32 is set to a predetermined low speed, is called the low-speed injection process. In the low-speed injection process, a vacuum valve (not shown) provided in the mold 6 is opened and the piston 32 moves at a low speed inside the injection sleeve 31, thereby pushing the air inside the injection sleeve 31 out of the cavity 61 and filling the passage from the injection sleeve 31 to the gate position with the molten metal. In the low-speed injection process, if the movement speed of the piston 32 is too fast, the molten metal will ripple and will draw in air, and if the movement speed is too slow, the temperature of the molten metal will drop and the fluidity of the molten metal will decrease. Furthermore, if the switching position is too close, air will be drawn into the molten metal, and if the switching position is too far back, the molten metal will flow into the cavity 61 at a low speed, resulting in a decrease in the quality of the die-cast item (product).

[0023] 3-2 to a position where the molten metal is filled into the cavity 61 (hereinafter referred to as the "filling position"), the movement speed of the piston 32 is set to a predetermined high speed. The process in which the piston 32 moves from the switching position to the filling position, i.e., the process in which the movement speed of the piston 32 is set to a predetermined high speed, is referred to as the high-speed injection process. In the high-speed injection process, the piston 32 moves at high speed inside the injection sleeve 31, so that the molten metal that has passed through the gate position becomes mist-like and enters every corner of the cavity 61 to form a casting.

[0024] As shown in Figure 3-3, when the high-speed injection process is completed and the cavity 61 is filled with the molten metal, the driving pressure of the piston 32 is increased to apply pressure to the molten metal. This process is called the filling completion / pressure increase process. In the filling completion / pressure increase process, the driving pressure of the piston 32 is increased to apply pressure to the molten metal, replenishing the molten metal to make up for the volumetric shrinkage caused by the solidification of the molten metal and creating a crushing effect on the air (air bubbles) entrained during the high-speed injection process.

[0025] The measuring device 5 is a device that measures the weight of the ladle 21 in a state where the molten metal is pumped from the molten metal furnace and the weight of the ladle 21 after the molten metal is poured from the ladle 21 into the injection sleeve 31. The measuring device 5 is, for example, a load cell 51 provided on the shaft 22 that suspends the ladle 21. As shown in FIG. 2, the load cell 51 is, for example, a compression direction load cell in which gravity acts in the compression direction, and is provided, for example, between the shaft 22 that suspends the ladle 21 and the ladle holding bracket 23 that holds the ladle 21. In the example shown in FIG. 2, the load cell 51 is provided between a hole 23a provided in the holding bracket 23 and a sliding part 24 that fits into a hole 234a and supports the shaft 22.

[0026] 4, the control device 4 according to this embodiment has a calculation unit 41 that calculates the weight of the molten metal poured into the injection sleeve 31, and a correction unit 42 that corrects the stroke position of the piston 32. The calculation unit 41 calculates the weight of the molten metal poured into the injection sleeve 31 by subtracting the weight of the ladle 21 after the molten metal has been poured from the weight of the ladle 21 in a state in which the molten metal has been pumped up. The correction unit 42 corrects a predetermined stroke position SP of the piston 32 based on the weight of the molten metal poured into the injection sleeve 31.

[0027] The correction unit 42 calculates a stroke for correcting a predetermined stroke position SP of the piston 32 from the weight of the molten metal poured into the injection sleeve 31 , the specific gravity of the molten metal, and the cross-sectional area of ​​the injection sleeve 31 .

[0028] [Manufacturing method for castings] The manufacturing method of the casting according to the embodiment is a manufacturing method of the casting in which the moving speed of the piston 32, which injects the molten metal poured into the injection sleeve 31 into the cavity 61 provided in the mold 6, is switched from a predetermined low speed to a predetermined high speed at a predetermined stroke position SP of the piston 32.

[0029] As shown in Figure 5, the manufacturing method for a casting according to the embodiment includes step S11 of measuring the weight of the ladle 21 when it has pumped up the molten metal, step S12 of pouring the molten metal into the injection sleeve 31 communicating with the cavity 61, step S13 of measuring the weight of the ladle 21 after the molten metal has been poured, step S14 of calculating the weight of the molten metal poured into the injection sleeve 31 by subtracting the weight of the ladle 21 after the molten metal has been poured from the weight of the ladle 21 when it has pumped up the molten metal, and step S15 of correcting a predetermined stroke position SP of the piston 32 based on the weight of the molten metal poured into the injection sleeve 31.

[0030] In step S15 of correcting the stroke position SP, a predetermined stroke position SP of the piston 32 is corrected based on the weight of the molten metal poured into the injection sleeve 31, the specific gravity of the molten metal, and the cross-sectional area of ​​the injection sleeve 31.

[0031] According to the manufacturing method for a casting according to the embodiment, the weight of the ladle 21 after the molten metal has been poured is subtracted from the weight of the ladle 21 in a state in which the molten metal has been pumped up to calculate the weight of the molten metal poured into the injection sleeve 31, and the predetermined stroke position SP of the piston 32 is corrected based on this weight. In this way, since the predetermined stroke position SP of the piston 32 is corrected based on the weight of the molten metal poured into the injection sleeve 31, it is possible to reduce variation in product quality.

[0032] The present invention is not limited to the above-described embodiment, and includes modifications to the above-described embodiment and appropriate combinations of these modifications. [Explanation of symbols]

[0033] 1. Die casting equipment 2 Pouring device 21 Raddle 22 Axis 23 Ladle Retaining Bracket 23a hole 24 Sliding parts 3 Injection device 31 Injection sleeve 31a Pouring spout 32 Piston 321 Plunger Tip 4. Control device 41 Arithmetic section 42 Correction section 5. Measurement equipment 51 Load Cell 6. Mold 61 Cavity 62 Mold parting surface (parting line) SP Predefined stroke position of the piston

Claims

1. A die casting facility that injects molten metal pumped from a molten metal furnace into a cavity provided in a die, A pouring device including a ladle for pumping the molten metal from the molten metal furnace; an injection device including an injection sleeve communicating with the cavity and into which the molten metal is poured from the ladle, and a piston movable within the injection sleeve and moving toward the cavity; a control device that switches a moving speed of the piston from a predetermined low speed to a predetermined high speed at a predetermined stroke position of the piston; A measuring device that measures the weight of the ladle when the molten metal is pumped up from the molten metal furnace and the weight of the ladle after the molten metal is poured from the ladle into the injection sleeve; Equipped with The control device includes: a calculation unit that calculates a weight of the molten metal poured into the injection sleeve by subtracting a weight of the ladle after the molten metal has been poured from a weight of the ladle in a state in which the molten metal has been pumped up; a correction unit that corrects a stroke position of the piston based on a weight of the molten metal poured into the injection sleeve; Die casting equipment with:

2. The die casting facility according to claim 1 , wherein the measuring device is a load cell provided on a shaft that suspends the ladle.

3. 3. The die casting equipment according to claim 1, wherein the correction unit calculates a stroke for correcting a stroke position of the piston from a weight of the molten metal poured into the injection sleeve, a specific gravity of the molten metal, and a cross-sectional area of ​​the injection sleeve.

4. A manufacturing method for a casting, comprising the steps of: switching a moving speed of a piston, which injects a molten metal poured into an injection sleeve into a cavity formed in a mold, from a predetermined low speed to a predetermined high speed at a predetermined stroke position of the piston, Measuring the weight of the ladle after pumping up the molten metal; pouring the molten metal into an injection sleeve communicating with the cavity; measuring the weight of the ladle after the molten metal has been poured; Calculating the weight of the molten metal poured into the injection sleeve by subtracting the weight of the ladle after the molten metal has been poured from the weight of the ladle when the molten metal has been pumped up; compensating a predetermined stroke position of the piston based on a weight of the molten metal poured into the injection sleeve; A method for producing a casting having the above structure.

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