Die-casting manufacturing method and apparatus

Abstract

Provided are a die cast manufacturing method and apparatus, with which it is possible to shorten a manufacturing cycle by allowing a die cast product to be extracted upon completion of cooling the product without having to wait until a biscuit part cools down. In the die cast manufacturing method and apparatus, after molten metal is injected into clamped molds by a first pressure application means, second pressure application is conducted by a second pressure application means via a runner that is directly connected to a cavity. In a state where filling of the cavity by the molten metal is completed by the first pressure application means, a passageway between a die cast product part and the biscuit part is disconnected so as to allow the second pressure application means to apply pressure to the die cast product part, thereby enabling the die cast product part and the biscuit part to be cut apart and to be extracted upon opening the molds.

Description

Technical Field

[0001] The present invention relates to a die casting manufacturing method and apparatus, and particularly to a die casting manufacturing method and apparatus stage capable of shortening a product manufacturing cycle.

Background Art

[0002] A die casting product casting method is carried out by forcing molten metal such as aluminum into a cavity formed by a mold using a plunger, and taking out a product having a shape conforming to the cavity. In order to suppress the occurrence of shrinkage cavities and improve product density when the product is cooled and molded, a method of further pressurizing a runner in conjunction with the pressurizing operation of a plunger of a die casting machine has been proposed. In this method, a pressurization pin that moves into and out of an ascending runner directly connected to the cavity is provided, and after the pressurization of the plunger by the primary pressurization means is completed, the pressurization pin of the runner is actuated to perform further pressurization (Patent Document 1). In this case, for product removal, the biscuit portion connected to the product portion is gripped, and the entire as-cast product consisting of the biscuit portion, the runner portion, the product portion, and the air vent portion is automatically taken out by a robot. In the pressurization from the runner of Patent Document 1, the pressurized portion and the front end biscuit surface of the plunger are in a connected state, which causes the molten metal to flow backward to the plunger side, resulting in a disadvantage that the feeding effect cannot be achieved.

[0003] From this perspective, the technology described in Patent Document 2 has been proposed, which maintains the strength of the runner portion connecting the product portion and the biscuit portion, while setting the gap between the inner diameter of the member forming the rising runner portion and the outer diameter of the pressure pin to 0.5 to 3.0 mm to provide a backflow prevention function and obtain a pushing effect (Patent Document 2). However, although the gap Δ between the inner diameter of the member forming the rising runner portion and the outer diameter of the pressure pin is set to 0.5 to 3.0 mm, in practice it is difficult to form such a cylindrical gap, and the gap becomes larger, requiring a certain gap length L. As a result, even when the pressure pin is inserted under pressure, molten metal flows back through the gap Δ, pushing the plunger back, and the intended backflow prevention effect cannot be obtained.

[0004] Furthermore, the die-cast product is removed after casting by gripping the biscuit portion with a robot chuck. The product portion and biscuit portion of the solidified casting, which is made by pushing a pressure pin into a cylinder where the runner portion has been machined and installed, are connected by a thin-walled cylindrical shape formed by the gap between the inner diameter of the cylinder and the outer diameter of the pressure pin. Therefore, if the gap between the rising runner portion cylinder and the moving runner portion pressure pin becomes too thin, the strength of the part connecting the biscuit portion and the product portion decreases, causing breakage during product removal and resulting in failure to remove the product, disrupting continuous production. Conversely, if this gap is made too large, the pressure effect of the second pressurization by the runner portion pressure pin will be diminished as molten metal will flow back through the gap. Furthermore, the manufacturing cycle time for die-cast products consists of mold clamping, molten metal filling, injection into the mold, cooling, mold opening, removal of as-cast product, injection of release agent, and mold clamping. However, the cooling time accounts for a large proportion of the cycle time, and is determined by the cooling time of the thick biscuit section, which takes the longest to cool. Therefore, there were limits to how much the product manufacturing cycle time could be shortened. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2000-117411 [Patent Document 2] Japanese Patent Publication No. 2011-224650 [Overview of the project] [Problems that the invention aims to solve]

[0006] The present invention aims to address the above-mentioned problems and provide a die-casting manufacturing method and apparatus that can shorten the manufacturing cycle by enabling the product to be removed as soon as the cooling of the die-cast product is complete, without waiting for the biscuit portion to cool. [Means for solving the problem]

[0007] The present invention is configured as follows to solve the above problems. This is a die-casting manufacturing method in which molten metal is injected into a clamped mold by a first pressurizing means, and then a second pressurizing means is applied through a runner directly connected to the cavity by a second pressurizing means, characterized in that, with the cavity completely filled with molten metal by the first pressurizing means, the passage between the die-cast product part and the biscuit part is separated, and the die-cast product part is pressurized by the second pressurizing means.

[0008] Furthermore, in this case, the first pressurizing means fills the mold with molten metal, and then the second pressurizing means separates the passage between the die-cast product portion and the biscuit portion using a pressure pin, while simultaneously pressurizing the die-cast product portion with the pressing force of the pressure pin. After pressurizing the product portion by the second pressurizing means, the die-cast product portion solidifies and the biscuit portion remains semi-solid when the mold is opened. The product or the removal projection connected to the product is then grasped by a product removal device, and the semi-solid biscuit portion is separated by the machine's mold extrusion or injection forward movement. Furthermore, the quality of the product is confirmed during casting by monitoring the stroke of the pressure pin.

[0009] The structure is such that the pressure exerted on the molten metal, including the die-cast product, by the pressure pin of the second pressure means is greater than the pressure exerted on the molten metal by the first pressure means.

[0010] In the center gate manufacturing method, after injecting molten metal into the clamped mold using a first pressurizing means, the spool portion installed in the fixed mold is pressurized using a second pressurizing means, characterized in that the pressurizing pin of the second pressurizing means is used to pressurize in such a way that it separates the die-cast product portion and the biscuit portion at the runner portion.

[0011] The die-casting apparatus according to the present invention is characterized by comprising: a first pressurizing means for injecting molten metal into a clamped mold; a second pressurizing means equipped with a pressurizing pin that operates after the completion of operation of the first pressurizing means and pressurizes a runner directly connected to the cavity; and a separating means provided at a position that separates and shields the die-cast product portion and the biscuit portion, wherein the separating means is provided with a control unit that, after the completion of operation of the first pressurizing means, enables the die-cast product portion and the biscuit portion to be separated and detached, and then enables the die-cast product portion to be pressurized by the second pressurizing means.

[0012] Furthermore, the device is characterized by comprising a first pressurizing means for injecting molten metal into a clamped mold, a second pressurizing means equipped with a pressurizing pin that operates after the first pressurizing means has completed its operation and pressurizes a runner directly connected to the cavity, and a pressurizing path for the pressurizing pin provided at a position that separates the die-cast product part and the biscuit part, wherein the pressurizing path can separate the die-cast product part and the biscuit part by the operation of the pressurizing pin, thereby separating the product part and the biscuit part, and thereafter a control unit is provided that allows the die-cast product part to be pressurized by the second pressurizing means.

[0013] In such a device, after the product portion is pressurized by the second pressurizing means, the control unit opens the mold while the die-cast product portion is solidified and the biscuit portion is still semi-solid. The product or the runner connected to the product is then grasped by the product removal device, and the semi-solid biscuit portion is separated by the machine's mold extrusion or injection forward movement.

[0014] Furthermore, the invention provides an injection unit having a first pressurizing means for injecting molten metal into a die-casting mold, and a second pressurizing means provided on the runner portion directly connected to the cavity at the bent portion of the runner that communicates with the cavity and applies pressure in the direction of the cavity, and after injection by the first pressurizing means is completed, a control unit is provided in the pressurizing path by the pressurizing pin of the second pressurizing means that separates and shields the die-cast product portion and the biscuit portion between itself and the pressurizing pin, and then enables the product portion to be pressurized by the pressurizing pin.

[0015] In this case, the control unit, after pressurizing the product portion by the second pressurizing means, opens the mold when the die-cast product portion has solidified and the biscuit portion is still semi-solid, grasps the product or the runner connected to the product with a product removal device, and separates the semi-solid biscuit portion by the machine's mold extrusion or injection forward movement. [Effects of the Invention]

[0016] In conventional die-casting equipment, the timing for removing the "as-cast" product, which consists of the biscuit, runner, product, and air vent sections after the molten metal has been injected into the mold, was done only after the entire "as-cast" product had solidified. The solidification rate differs depending on whether it is the biscuit, runner, product, or air vent section. The solidification rate is proportional to the square of the wall thickness. For example, if the product thickness is 3 mm, the cooling time for the product section is 3 mm ⇒ approximately 0.09 seconds, and if the biscuit section is 30 mm thick, the cooling time for the product section is 30 mm ⇒ 9 seconds. In most cases, the thicker biscuit section solidifies the slowest, and the solidification rate of the biscuit section determined the cycle time, and thus the productivity, of die-cast product manufacturing.

[0017] In this invention, by using a runner pressure pin that is pressed into the runner portion to separate the product portion from the biscuit portion, the mold can be opened and the product portion removed as soon as the product portion has solidified, without waiting for the biscuit portion, which has a long solidification time, to solidify. This shortens the cycle time and improves the productivity of die-cast product manufacturing. For example, if the product portion thickness is 3 mm and the biscuit portion is 30 mm, the time to remove the "as-cast" product is reduced from 9 seconds to 0.09 seconds, significantly shortening the cycle time and improving productivity. In addition, since the product portion can be removed when it is less solidified than before, the effects of product deformation and galling during removal are also reduced.

[0018] For the runner portion to be pushed in by the runner pressure pin, separating the product portion and the biscuit portion at the runner portion, the runner portion must be cut by the weight of the biscuit portion when the mold opens, causing the biscuit portion to fall. For this reason, the gap formed by the diameter of the runner portion and the diameter of the runner pressure pin must be less than or equal to the thickness of the biscuit portion so that it falls by its own weight. This gap is also such that there is no backflow of molten metal when the runner is pressurized. Because there is no backflow, the molten metal is pushed into the product portion, which has already been filled by the first pressurizing means, at high pressure by the second pressurizing by the runner pressure pin. By starting the pushing operation of the runner pressure pin into the runner portion at a timing when the area of ​​the product portion in contact with the mold has solidified, but the center of the product has not yet solidified, the molten metal of the product portion before solidification can be pushed in, effectively increasing its density.

[0019] Furthermore, by monitoring the stroke of the pressure pin (or the cylinder stroke), the amount of molten metal pushed in can be measured, allowing for verification of product quality during casting.

[0020] In the conventional runner pressing that does not separate the product portion and the biscuit portion, the product portion ejection chucking portion after cooling becomes the biscuit portion. It is necessary to set the runner diameter and the runner pressing pin diameter such that the biscuit portion and the product portion do not separate during ejection, and it is required to adjust the gap to minimize backflow and prevent separation. However, in the runner pressing and separating method according to the present invention, there is no backflow at all, so the stroke amount equals the increased product weight amount, which facilitates management. [Brief Description of the Drawings]

[0021] [Figure 1] It is a cross-sectional view of essential parts of a die-casting manufacturing apparatus according to an embodiment. [Figure 2] They are a cross-sectional view of a pressing pin installed in a die-casting manufacturing apparatus and a cross-sectional view of a modified example. [Figure 3] It is an explanatory view illustrating taking out the die-cast product and the biscuit portion separately after opening the mold of the apparatus. [Figure 4] It is a configuration diagram of a pin stroke detection device. [Figure 5] It is a cross-sectional view of runner pressing by a center gate manufacturing method. [Mode for Carrying Out the Invention]

[0022] Hereinafter, a die-casting manufacturing method and a manufacturing apparatus according to embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description is merely one embodiment, and the present invention can include various modified examples without departing from the spirit of the present invention.

[0023] FIG. 1 shows a cross-sectional view of essential parts of a die-casting manufacturing apparatus according to a first embodiment. The die-casting manufacturing apparatus 10 includes a movable mold 14 attached to a movable platen 12, and a fixed mold 18 attached to a fixed platen 16. Molten metal is injected into a cavity 20 formed by bringing the two molds 14 and 18 into contact with each other, and a product having a shape conforming to the cavity 20 is obtained. The die-cast product can be taken out from the cavity 20 by separating the molds 14 and 18 and actuating an ejection pin 22 provided on the back surface of the movable mold 14.

[0024] A molten metal supply means 24 is positioned below the cavity 20 as an injection unit for supplying molten metal to the cavity 20 of such a die-casting manufacturing apparatus 10. This consists of a first pressurizing means 30 comprising an injection sleeve 26 that is mounted horizontally through the fixed platen 16 and reaches the fixed mold 18, a plunger 28 disposed inside the injection sleeve 26, and a pressurizing device located behind the plunger 28 that can push and pull the plunger 28.

[0025] A runner 32 is formed at the front end of the injection sleeve 26, which serves as a passage for molten metal through the biscuit 31 to the cavity 20. This runner 32 consists of a splitter runner section 34 that extends almost horizontally from the injection sleeve 26 and a rising runner section 36 that is turned upward so as to be directly connected to the lower part of the cavity 20. The molten metal pushed out by the plunger 28 of the first pressurizing means 22 passes through the splitter runner section 34, is turned upward by the rising runner section 36, and is injected into the cavity 20.

[0026] In the rising runner portion 36 of such a runner 32, a second pressurizing means 38 is provided to secondarily pressurize the molten metal in the cavity 20. This second pressurizing means 38 consists of an actuator (hydraulic cylinder) 40 equipped at the bottom of the molds 14 and 18, and a pressurizing pin 42 that is mounted to move in and out from the bottom to the top of the rising runner portion 36 by the actuator. The diameter d of the pressurizing pin 42 is smaller than the inner diameter D of the rising runner portion 36, but is approximately the same diameter, so that the pressurizing pin 42 can slide up and down in the rising runner portion 34 while also being able to divide and shield the molten metal. Therefore, the amount of pressure the pressurizing pin 42 is pressed into the rising runner portion 36 improves the density of the product in the cavity 20.

[0027] In this embodiment, in particular, in the straight passage from the intersection of the rising runner section 36 and the flow divider runner section 34 (section AB in Figure 2(1)) to the gate of the upper rising runner section 36, the inner diameter D of the area up to the stroke end of the pressure pin 42 (section AC in Figure 2(1)) is set to D = d + 0.1 mm to d + 0.5 mm, where d is the outer diameter of the pressure pin 42. Preferably, it is set to D = d + 0.2 mm to d + 0.4 mm. This is to ensure the range of motion of the pressure pin 42 and to prevent molten metal from entering the gap.

[0028] The second pressurizing means 38, configured in this way, begins pressurizing from the position shown in Figure 2(1)A after the injection by the plunger 28 of the first pressurizing means 30 is completed. As shown in Figure B, when the pressurizing pin 42 just blocks the diverter runner section 34, it exerts a separating effect between the product section 35 and the biscuit section 31 at that point. Therefore, when the pressing operation of the pressurizing pin 42 reaches Figure 2(1)C, the amount of molten metal filling into the cavity 20 increases, the stroke of the pressurizing pin 42 lengthens, and the manufacturing process is completed. At this time, the die-cast product section 35 and the biscuit section 31 in the cavity 20 are completely separated. As shown in Figure 3, the molds 14 and 18 are opened during the solidification time of the die-cast product section 35, and even if the biscuit section 31 is still hot and has not cooled completely, the die-cast product 35 can be removed by the chuck robot 41, and the separated biscuit section 31 can fall by its own weight. These drive controls can be performed by a separate control unit.

[0029] In this configuration, the product portion and the biscuit portion 31 are separated by a runner pressure pin 42 that is pressed into the runner portion. As a result, the molds 14 and 18 can be opened and the product portion removed as soon as the product portion has solidified, without waiting for the biscuit portion 31, which has a longer solidification time, to solidify. This shortens the cycle time and improves the productivity of die-cast product manufacturing. When the product portion thickness is 3 mm and the biscuit portion 31 is 30 mm, the time to remove the "as-cast" product is reduced from 9 seconds to 0.09 seconds, shortening the cycle time and improving productivity. In addition, since the product portion can be removed when it is less solidified than before, there is also the effect of reducing product deformation and galling during removal.

[0030] In order for the runner portion 31 to separate the product portion and the biscuit portion 31 at the runner portion 31 using the runner pressure pin 42 that pushes the runner portion 31, the runner portion must be cut by the weight of the biscuit portion 31 when the molds 14 and 18 open, causing the biscuit portion 31 to fall. For this reason, the gap formed by the diameter of the runner portion 31 and the diameter of the runner pressure pin 42 is made to be less than or equal to the thickness of the biscuit portion 31 so that it falls by its own weight. Also, a gap of the same size is sufficient to prevent backflow of molten metal when the runner is pressurized. Because there is no backflow, the molten metal is pushed at high pressure by the second pressurization by the runner pressure pin 42 into the product portion which has already been filled by the first pressurization means 24. By starting the pushing operation of the runner pressure pin 42 into the runner portion at a timing when the area of ​​the product portion in contact with the mold has solidified, but the center of the product has not yet solidified, the molten metal of the product portion before solidification can be pushed in, effectively increasing its density.

[0031] As a result, the die-casting time can be used as the cycle time, and it is no longer affected by the cooling time of the biscuit. In addition, since it is not necessary to hold the biscuit 31 when removing the die-cast product, product deformation and galling during product removal are eliminated.

[0032] Furthermore, by using runner pressure pins to separate the die-cast product from the biscuit portion, and by applying pressure to the product while the central part is still unsolidified, molten metal can be pressed into the die-cast product portion at a higher casting pressure (approximately 70 MPa to approximately 280 MPa) while maintaining the conventional clamping force (projected area * casting pressure), thereby significantly increasing the internal density.

[0033] Figure 2(2) shows a modified example of the pressure pin 42. In this example, an annular projection 43 with a diameter D is provided at the entrance of the rising runner portion 36. The inner diameter D of the annular projection 43 and the diameter d of the pressure pin 42 are set to D = d + 0.1 mm to d + 0.5 mm. Preferably, D is set to d = d + 0.2 mm to d + 0.4 mm. The diameter E of the rising runner 36 is larger than D, and the dimensions do not need to be precise. With this configuration, there is almost no gap between the annular projection 43 and the pressure pin 42, and molten metal does not leak out through this gap. Compared to the example in Figure 2(1), this ring-shaped design has the advantage of being easier to process.

[0034] Furthermore, by monitoring the stroke of the pressure pin (or the cylinder stroke), the quality of the product can be checked during casting. The runner pressure interruption method eliminates backflow, resulting in increased stroke and increased product weight, making management easier. This can be achieved with the following configuration. Figure 4 is a diagram of the pin stroke detection device. As shown in the figure, the hydraulic discharge path 44 when the pressure pin 42 rises is configured to measure the piston drive amount of the main actuator 40 and, consequently, the stroke of the pressure pin 42, from the amount of discharged oil. This stroke detection device 46 is composed of a cylinder piston structure, which consists of a cylinder body 48 and a piston 50 that can slide inside it. One chamber of the cylinder body 48, partitioned by the piston 50, is connected to the hydraulic fluid outlet of the pressure pin 42, and the other chamber is connected to a directional control valve 52. As a result, the hydraulic fluid discharged from the main actuator 40 enters the stroke detection device 76 in the same amount, and the piston 50 is moved. A rod 54 is integrally attached to the piston 50, which protrudes from one end of the cylinder body 48 and is connected to a linear potentiometer 56. The starting point of the rod 54 is one end of the cylinder body 48 (the left end in Figure 3), which coincides with the starting point of pressurization of the pressure pin 42 (the lower end in Figure 3). The linear potentiometer 56 is positioned parallel to the rod 54 and moves together with the rod 54 to determine the distance of movement. In such a stroke detection device 46, the piston 50 is provided with a through hole that connects the chambers partitioned by the piston 50, and a check valve 58 and an orifice (throttling valve) 60 are attached to this through hole. This check valve 58 is a one-way valve that prevents the flow of hydraulic fluid from being pushed out from the chamber containing the hydraulic fluid of the pressure pin 42 to the chamber on the directional control valve 52 side, while allowing flow in the reverse direction. As a result, the total amount of hydraulic fluid when the pressure pin 42 is pressurizing is detected by the stroke detection device 46. The orifice (throttling valve) 59 regulates the flow rate of the check valve 58. Also, if the cracking pressure (spring force) of the check valve 58 is weak, the piston will stop and the fluid will flow through the check valve, so this can be solved by throttling the flow rate. Furthermore, a separate control system is provided to control the aforementioned operating system and ensure that it operates properly.

[0035] By providing such a stroke detection device 46 for the pressure pin 42, accurate monitoring of the pressure pin is possible, and the amount of secondary pressure applied to the die-cast product can be measured through this process alone.

[0036] Next, Figure 5 shows an example of application to the "center gate method." The "center gate method" is applied to circular and conical shaped parts and point-symmetrical parts, but in order to improve the filling balance, it is used by filling the molten metal from the center of the cavity 66.

[0037] As shown in Figure 5, the apparatus for implementing this center gate manufacturing method includes a second movable mold 64 between a fixed mold 60 and a movable mold 62. A circular cavity 66 is formed between the movable mold (hereinafter referred to as the first movable mold) 62 and the second movable mold 64, and a spool 70 connecting this cavity 66 and the runner 68 is formed in the second movable mold 64. The spool 70 is formed in a conical shape, with its apex located in the center of the circular cavity 66. Molten metal is supplied from its apex, allowing the molten metal to spread throughout the cavity 66 via the spool 70. The runner 68 is formed on the mold-fitting surface of the fixed mold 60, bends at a right angle from the apex of the spool 70 and extends downward, connecting to a plunger sleeve 72 located below the fixed mold 60 and extending horizontally. A plunger 74 is inserted into the plunger sleeve 72, and is subjected to primary pressure by an actuator (not shown) to inject molten metal. The pressurizing means including this plunger 74 is the first pressurizing means 76.

[0038] Opposite the apex of the spool 70, a second pressurizing means 80 is provided on the fixed mold 60 side. This consists of a pressurizing cylinder 82 and a pressurizing pin 84 that moves in and out of it, and the pressurizing pin 84 is configured to move in and out toward the apex of the spool 70 formed in the second movable mold 64. Specifically, as shown in detail in the enlarged section of Figure 5, a bent passage 86 provided at the point connecting the runner 68 and the spool 70 serves as the passage for the pressurizing pin 84 to move in and out, and this is formed inside the second movable mold 64 and serves as a passage leading to the cavity 66. The pressurizing pin 84 crosses the runner 68 and pressurizes the cavity 66 as soon as it reaches the bent passage 86.

[0039] Here, the relationship between the inner diameter D of the bent passage 86 and the outer diameter d of the pressure pin 84 is set to D = d + 0.1 mm to d + 0.5 mm. Preferably, it is set to D = d + 0.2 mm to d + 0.4 mm. This is to ensure the range of motion of the pressure pin 84 and to prevent molten metal from entering the gap. As shown in the enlarged view of Figure 5 (the lower part of the same figure), the amount of pressure applied by the pressure pin 84 becomes the amount of pressure applied to the cavity 66.

[0040] To explain the actual work process of this "center gate manufacturing method," first, in the clamped state, the first pressurizing means 76, the gate cutting hydraulic cylinder 78, and the second pressurizing means 80 are all in standby mode, and molten metal is first poured from the pouring port of the plunger sleeve 72. After the pouring is complete, the operation of the first pressurizing means 76 is started, and it is moved at high speed while low-speed, high-pressure injection is performed at the forward limit to complete the process. The molten aluminum enters the runner 68, rises, passes through the bent passage 86, and fills the cavity 66 from the spool 70. After the injection operation by the first pressurizing means 76 is completed, secondary pressurization is performed by the second pressurizing means 80. This is done by pushing out the pressurizing pin 84 from the standby position of the second pressurizing means 80 (upper view of enlarged view in Figure 5) by the pressurizing cylinder 82, crossing the runner 68, and reaching the bent passage 86, where the pressurizing pin 84 performs its function of dividing and shielding the molten metal. Therefore, the separation function of the pressure pin 84 increases the amount of molten metal filled into the cavity 66, and the pushing action of the pressure pin 84 lengthens the stroke, completing the operation. Next, the first movable mold 62, including the second movable mold 64, retracts, and the intermediate mold opens to one side. This leaves the runner 68 attached to the cavity 66 side. In this open state, the die-cast product part and the biscuit part 31 are separated, making it easy to remove the biscuit. Finally, the first movable mold 62 is moved further back, widening the space between the second movable mold 64 of the intermediate mold and the first movable mold 62, and the product is removed from the cavity 66 to complete the process.

[0041] Thus, with the "center gate manufacturing method," the pressure pin 84 of the second pressurizing means 80, which pressurizes the spool 70 located in the center of the cavity 66, blocks the bent passage 86 leading to the product section, completely blocking backflow of molten metal and maintaining pressure, thereby enabling additional pressurization of the product section. Consequently, it becomes unnecessary to place the second pressurizing means 80 at the bottom of the runner 68, and the second pressurizing means 80 does not get in the way.

[0042] Thus, the effects of the present invention can be fully obtained even with the center gate manufacturing method. In other words, according to this embodiment, there is no need to place a hydraulic cylinder for gate cutting. Even if one is placed, it is sufficient to simply peel the runner part from the second movable mold 64. Since the die-cast product part and the biscuit part 31 are separated, the cycle can be set up in the time it takes for the die-cast product part to cool and solidify, and the biscuit part 31 does not need to be completely cooled during heating, so the product manufacturing cycle time can be greatly reduced. [Industrial applicability]

[0043] In this invention, after injecting molten metal into a clamped mold using a first pressurizing means, a second pressurizing means is applied through a runner directly connected to the cavity. In this invention, the die-cast product part and the biscuit part can be separated and pressurized by the second pressurizing means while the molten metal has been completely filled into the cavity by the first pressurizing means, thereby shortening the product manufacturing cycle time. [Explanation of symbols]

[0044] 10... Die-casting manufacturing equipment, 12... Moving platen, 14... Movable mold, 16... Fixed platen, 18... Fixed mold, 20... Cavity, 22... Ejection pin, 24... Hot water supply means, 26... Injection sleeve, 28... Plunger, 30... First pressurizing means, 32... Runner, 34... Diverter runner section, 36... Rising runner section, 38... Second pressurizing means, 40... Actuator, 42... Pressurizing pin, 44... Hydraulic discharge path, 46... Pin stroke detection device, 48... Cylinder body, 50... Piston, 52... Directional control valve, 54... Rod, 56... Potentiometer, 58... Check valve, 59... Throttle valve, 60... Fixed mold, 62... First movable mold, 64... Second movable mold, 66... ​​Cavity, 68... Runner, 70... Spool, 72... Plunger sleeve, 74... Plunger, 76... First pressurizing means, 78... Hydraulic cylinder for gate cutting, 80... Second pressurizing means, 82... Pressurizing cylinder, 84... Pressurizing pin, 86... Bent passage.

Claims

1. A die-casting manufacturing method comprising injecting molten metal into a clamped mold using a first pressurizing means, and then applying a second pressurizing means through a runner directly connected to the cavity, A die-casting manufacturing method characterized by operating a second pressurizing means when the cavity is completely or nearly filled with molten metal by a first pressurizing means, thereby separating the passage between the die-cast product section and the biscuit section, and then pressurizing the die-cast product section with the second pressurizing means while blocking the molten metal through an annular projection provided at the runner inlet immediately after the separation.

2. The die-casting method according to claim 1, characterized in that, after pressurizing the product portion by the second pressurizing means, the die-cast product portion is solidified and the biscuit portion is left semi-liquid when the mold is opened, the product or the runner portion connected to the product is grasped by a product removal device, and the semi-liquid or solidified biscuit portion is separated by the mold extrusion or injection forward movement of the machine.

3. The die-casting method according to claim 1, characterized in that the quality of the product is confirmed during casting by monitoring the stroke of the pressure pin of the second pressurizing means, and it is determined whether the stroke has reached the position where it will be divided.

4. The die-casting method according to claim 1, characterized in that the structure is such that the pressure acting on the molten metal including the die-cast product portion by the pressure pin of the second pressure means is greater than the pressure acting on the molten metal by the first pressure means.

5. A die-casting manufacturing method characterized in that, in a center gate manufacturing method, after injecting molten metal into a clamped mold by a first pressurizing means, pressurizing the spool portion installed in the fixed mold by a second pressurizing means, the runner portion connecting the die-cast product portion and the biscuit portion is separated by a pressurizing pin of the second pressurizing means, and the product is pressurized by the pressurizing pin while blocking the molten metal through an annular projection provided at the runner entrance immediately after separation.

6. A die-casting manufacturing apparatus characterized by comprising: a first pressurizing means for injecting molten metal into a clamped mold; a second pressurizing means equipped with a pressurizing pin that operates after the completion of operation of the first pressurizing means and pressurizes a runner directly connected to the cavity; a separating means provided at a position that separates and shields the die-cast product portion and the biscuit portion; an annular projection provided at the runner inlet immediately after separation to shield the molten metal; and a control unit provided that, after the completion of operation of the first pressurizing means or nearly filling, enables the die-cast product portion to be separated from the biscuit portion, thereby enabling the die-cast product portion to be separated from the biscuit portion, and then enables the die-cast product portion to be pressurized by the second pressurizing means after the annular projection has passed.

7. A first pressurizing means for injecting molten metal into a clamped mold, A second pressurizing means, which operates after the first pressurizing means has completed operation or is nearly filled, and is equipped with a pressurizing pin that pressurizes a runner directly connected to the cavity, The pressure path of the pressure pin, which is provided at a position that separates the die-cast product part and the biscuit part, An annular projection is provided at the runner entrance immediately after the division to block the molten metal, The die-casting manufacturing apparatus is characterized by having a control unit that allows the pressurizing path to separate and detach the die-cast product portion and the biscuit portion by the operation of a pressurizing pin, and then allows the die-cast product portion to be pressurized by a second pressurizing means that has passed through the annular projection.

8. The die-casting manufacturing apparatus according to claim 6 or 7, characterized in that, after the product portion is pressurized by the second pressurizing means, the die-cast product portion is solidified and the biscuit portion is in a semi-solid or solidified state when the mold is opened, the product or the runner connected to the product is grasped by the product removal device, and the semi-solid biscuit portion is separated by the mold extrusion or injection forward movement of the machine.

9. A first pressurizing means for injecting molten metal into a die-casting mold, An injection unit is provided which has a runner that communicates with the cavity bent, and a second pressurizing means provided on the runner portion directly connected to the cavity at the bent portion that applies pressure in the direction of the cavity, An annular projection through which the pressure pin can be inserted into the runner inlet portion which serves as the pressure path, We have established A die-casting manufacturing apparatus characterized by having a control unit that, after injection by the first pressurizing means is completed, is provided in the pressurizing path by the pressurizing pin of the second pressurizing means, which separates and shields the die-cast product part and the biscuit part from the pressurizing pin, and then enables pressurizing of the product part by the pressurizing pin.

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