Die-casting manufacturing method and device

Abstract

To arbitrarily arrange runner compression means when compressing a runner after molten metal injection by a plunger in a die cast manufacturing method.SOLUTION: After injecting a molten metal by first compression means to a mold clamped in a die cast manufacturing method, when second compression is performed through a runner directly connected to a cavity by the second compression means, the runner is bent and formed, second compression means is provided in a runner part directly connected to the cavity in the bent part and an orifice is arranged, and the compression is performed by the second compression means while preventing the backflow of the molten metal by a metal seal with a compression pin of the second compression means in the orifice portion.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a die-casting manufacturing method and apparatus, and more particularly to a die-casting manufacturing method and apparatus that eliminates obstacles when pressurizing the runner portion, which is the inlet for molten metal in the die, from below. [Background technology]

[0002] Conventionally, two known methods for casting die-cast products are the "normal die-casting method" shown in FIG. 13 and the "center gate method" shown in FIG.

[0003] The most common "normal die-casting method" involves forcing molten aluminum or other metal into a cavity made in a mold with a plunger, and then removing a product that cools and solidifies to match the shape of the cavity.In order to reduce the occurrence of voids when the product is cooled and molded, and to improve product density, a method has been proposed in which the runner is further pressurized in conjunction with the pressurizing operation of the plunger of the die-casting machine.

[0004] The runner consists of a branch runner section that runs along the extrusion direction of the plunger and a rising runner section that runs perpendicular to this and faces upward. In order to perform secondary pressurization through the runner, a pressure pin that moves in and out of the rising runner that is directly connected to the cavity is provided, and after the plunger pressurization is completed, the pressure pin of the runner is activated to perform further pressurization (Patent Document 1).

[0005] In Patent Document 1, when pressure is applied from the runner, the pressure applying portion and the plunger tip surface are connected, and the pressure that can be applied must not exceed the mold clamping force, calculated by multiplying the casting pressure by the mold projected area. With a typical casting machine, this limit pressure is about 70 MPa, and pressures beyond this cannot be applied. From this perspective, Patent Document 2 proposes a technology in which the gap between the inner diameter of the member forming the rising runner and the outer diameter of the pressure pin is set to 0.5 to 3.0 mm, thereby preventing backflow and achieving a pushing effect (Patent Document 2).

[0006] This method, which focuses solely on the gap, is impractical due to the following drawbacks. Normally, the product is removed by grasping the biscuit portion after casting. However, when a pressure pin is inserted into a cylinder with a machined runner section, the product and biscuit portions of the solidified casting are connected by a thin cylindrical gap formed between the cylinder's inner diameter and the pressure pin's outer diameter. Therefore, as the travel length L of the runner pressure pin moving through the rising runner cylinder increases, the strength of the portion connecting the biscuit portion and the product decreases, resulting in breakage during product removal and failure, hindering continuous production. Generally, the flow rate Q of the annular gap is proportional to the cube of the annular gap Δ and inversely proportional to its length L. Therefore, reducing the gap Δ is effective in preventing backflow, and the limit at which the pressure pin can apply pressure to the product from the runner section is determined by this gap Δ and its length L. Meanwhile, the travel distance of the pressure pin is determined by the predicted volume of porosity in the product. The shrinkage rate of molten aluminum is approximately 6%, and to prevent the occurrence of shrinkage cavities, it is necessary to move the pressure pin so that it compresses the molten metal by approximately 2% of the product volume. To enable continuous casting by applying pressure from the runner section, it is necessary to set optimal values for three elements: the value of the gap Δ between the rising runner section and the pressure pin, the amount of movement L of the pressure pin, and the strength required to connect the biscuit and the product, which is necessary to remove the product after casting. However, continuous casting is difficult with only the element of setting the gap Δ between the inner diameter of the rising runner and the outer diameter of the pressure pin to 0.5 to 3.0 mm, and the expected effect cannot be obtained, which is an issue.

[0007] In response to this issue, the present inventors have invented a convex groove orifice structure, as shown in Figure 13. This structure involves injecting molten metal into the clamped fixed mold 1 and movable mold 2 using a first pressurizing device 3. Then, a cylindrical portion is machined and installed in a runner 6 directly connected to a cavity 5 by a second pressurizing device 4, and a pressurizing pin 7 moves along the runner. The second pressurizing device 4 then applies second pressurization to the cavity using a moving pressurizing pin 7. The cylinder of the second pressurizing device 4 is provided with a convex groove orifice 8, and a metal seal at the orifice 8 prevents backflow of molten metal while the second pressurizing device 4 pressurizes the cavity. This convex groove orifice 8 prevents backflow and minimizes the length of the thin section connecting the biscuit and product after solidification, thereby improving strength. The required stroke of the pressurizing pin 7 in the runner is correlated with the expected shrinkage cavity generation capacity and is determined by the volume of the product. However, in the past, the required stroke required a long section connecting the biscuit and product, which resulted in insufficient strength. By installing a convex groove orifice, both backflow prevention and breakage prevention strength during product removal can be achieved by determining only the gap Δ and the convex groove orifice width, without being affected by the required pressure pin stroke length. Furthermore, in conventional technology, the gap length where the pressure pin 7 is inserted into the cylinder varies depending on the movement of the pressure pin 7. The flow rate Q of the annular gap is proportional to the cube of the annular gap Δ and inversely proportional to its length L, so the backflow prevention effect increases with the pressure pin stroke length. On the other hand, when a convex groove orifice 8 is installed, assuming that the pressure pin at least passes through the orifice portion, the backflow prevention effect is determined solely by the gap Δ and is not affected by the pressure pin stroke length. In other words, the backflow prevention effect is determined by the orifice gap length L and gap Δ, which are variable values that change with the stroke movement, but are fixed values. This indicates that it is easier to design an optimal runner pressure pin cylinder to achieve stable backflow prevention.

[0008] In the "normal die-casting method," the runner 6 is located at the bottom of the product, and molten aluminum is injected upward from below toward the cavity 5, but the second pressurizing means 4 applies second pressure to the rising runner section that connects the diverter runner section formed by the first pressurizing means 3 to the cavity beyond, so the second pressurizing means 4 has a diverter formed by the first pressurizing means. The diverter is equipped with a cooling means, but this interferes with the second pressurizing means 4, making it difficult to position the second pressurizing means 4, and it was necessary to manufacture a new diverter when applying runner pressure.

[0009] Furthermore, the "center gate manufacturing method" shown in Figure 14 is applied to conical shaped parts and point-symmetric parts, and is used to fill the molten metal from the center of the cavity 5 to improve filling balance. In Patent Document 3, a second movable mold 9 is provided between the fixed mold 1 and the movable mold 2, and a spool 10 is provided here to connect the cavity 5 and the runner 6, so that the molten metal spreads throughout the cavity 5. Then, when injection is completed and the product solidifies and is to be removed, the runner portion is cut away with a gate cutting cutter 11, and then the movable molds 2 and 9 are separated from each other, and the product holding the spool 10 is removed, as shown in Figure 15.

[0010] In this way, the "center gate method" can achieve a certain degree of effect in improving the product density of die-cast products by applying runner pressurization, a second pressurizing means, from below, just like the "normal die casting method." However, while the gate, which is the entrance for molten metal, is located at the bottom of the cavity in the "normal die casting method," the "center gate method" moves the gate upward and positions it in the center of the cavity, meaning that the second pressurizing means 4 located at the bottom is cut and removed by the gate-cutting cutter 11 when removing the gate. In addition, there are issues with the pressurizing pin 7 of the second pressurizing means being positioned away from the cavity gate, making it difficult to transmit high pressure, so the effect is not as great as with the "normal die casting method." There is also the issue of interference between the cooling means for the shunt and the second pressurizing means, just like the "normal die casting method." [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Patent Publication No. 2000-117411 [Patent Document 2] Patent Publication No. 2011-224650 [Patent Document 3] Patent No. 6134776 Summary of the Invention [Problem to be solved by the invention]

[0012] The present invention focuses on the above-mentioned problems with the "normal die casting method" and the "center gate method," and aims to facilitate mold processing by enabling, when installing a second pressurizing means for the "normal die casting method" and the "center gate method" after molten metal is injected by the plunger, the pressurizing means to be positioned so that it does not interfere with the cooling means for the diverter, and by increasing the freedom of selection of the placement positions of the runner section pressurizing means and spool section pressurizing means even when there is no interference with cooling means such as biscuits.

[0013] In addition, the problem of a reduction in the pressurizing effect due to the longer distance from the pressurizing pin to the cavity gate, which is an issue when installing a second pressurizing means in the rising runner section for the "center gate manufacturing method," is addressed by applying a spool section pressurizing means that is closer to the cavity gate, thereby aiming to avoid the reduction in the pressurizing effect. [Means for solving the problem]

[0014] In order to achieve the above-mentioned object in the "normal die-casting method," if the biscuit cooling means makes it difficult to place the second pressure means, we devised a method of avoiding interference with the biscuit cooling means by bending the rising runner into a U-shape or V-shape. The second pressure means after bending is installed as shown in Figure 2 if it is U-shaped, or as shown in Figure 5 if it is V-shaped. When applying second pressure through a runner directly connected to the cavity, an orifice is installed, which makes it possible to avoid interference with the biscuit cooling means without reducing the pressure effect of the second pressure pin. In this case, the bent portion is characterized by being U-shaped or V-shaped.

[0015] The die-casting manufacturing apparatus according to the present invention for a "normal die-casting method" is characterized by having an injection section comprising a first pressurizing means for injecting molten metal into a die-casting mold, a second pressurizing means provided in the runner section directly connected to the cavity at the bent section by bending the runner communicating with the cavity and applying pressure in the direction of the cavity, and an orifice provided in the pressurizing path of the pressurizing pin of the second pressurizing means and capable of shielding the molten metal from the pressurizing pin. In this case, the bent section is characterized by being U-shaped or V-shaped.

[0016] The die-casting manufacturing apparatus of the present invention for the "center gate manufacturing method" is characterized by having an injection section consisting of a first pressurizing means for injecting molten metal into a die-casting mold, a second pressurizing means for pressurizing the portion bending from the rising runner toward the spool toward the cavity, and an orifice that is provided in the pressurizing path of the pressurizing pin of the second pressurizing means and can shield the molten metal from the pressurizing pin. In this case, the pressurizing pin of the second pressurizing means is installed in a fixed mold that is relatively easy to install in a three-piece mold, and presses toward the cavity center. [Effects of the Invention]

[0017] In the "normal die casting method," the runner section is pressurized as described above. After injection by the plunger as the first pressurizing means, the molten metal is pressurized by the pressurizing pin as the second pressurizing means. The second pressurizing means and orifice that pressurize the runner form a metal seal due to their throttling effect, blocking backflow and maintaining pressure, thereby enabling additional pressurization of the product section. The second pressurizing means and orifice are located at the runner bend, which is positioned to avoid the cooling means, allowing for flexible placement of the pressurizing direction of the second pressurizing means. This eliminates interference with the biscuit cooling device and facilitates avoidance of the mold core. Furthermore, even when there is no interference with the biscuit cooling device, bending the runner to install the second pressurizing device allows for flexible changes to the installation location of the second pressurizing device and the direction of operation of the pressurizing pin, thereby improving the design flexibility of the second pressurizing device installation.

[0018] In the "center gate manufacturing method," the second pressurizing means installed in the fixed mold pressurizes the molten metal with a pressurizing pin as the second pressurizing means after injection by the plunger as the first pressurizing means. The second pressurizing means that pressurizes the spool part and the orifice form a metal seal due to their throttling effect, blocking backflow and maintaining pressure, thereby enabling additional pressure to be applied to the product part.

[0019] Furthermore, by installing the orifice, it becomes possible to adjust the thickness of the cylindrical thick-walled part connecting the runner part and the spool part, and it becomes possible to set the thickness to make it easier to cut with a punch using a hydraulic cylinder. Although it is proportional to the orifice gap length L, by determining the orifice gap length L to thin the gap Δ to a strength that makes it easy to cut, it becomes possible to make cutting easy. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a cross-sectional view of a main part of a die-casting manufacturing apparatus according to an embodiment. [Figure 2] FIG. 2 is a schematic side view of FIG. [Figure 3]FIG. 4 is a cross-sectional view for explaining a runner pressurizing portion. [Figure 4] FIG. 10 is a time-series diagram showing a runner pressurization state. [Figure 5] FIG. 10 is a side view of a main part of a die-casting production apparatus according to a second embodiment of the present invention. [Figure 6] A cross-sectional view of runner pressurization using the center gate manufacturing method. [Figure 7] FIG. 1 is a cross-sectional view of a main part of an apparatus that employs a center gate manufacturing method, showing the state in which hot water is being supplied. [Figure 8] FIG. 2 is a diagram showing an injection state by the first pressurizing means. [Figure 9] FIG. 4 is a diagram showing the state of pressure applied by the second pressure applying means. [Figure 10] FIG. [Figure 11] FIG. [Figure 12] FIG. [Figure 13] FIG. 1 is a cross-sectional view of a main part of a manufacturing device that performs a "normal die-casting method." [Figure 14] FIG. 1 is a cross-sectional view of a main part of a manufacturing device that performs the "center gate manufacturing method." [Figure 15] FIG. 2 is a cross-sectional view of a main part of a manufacturing device showing a runner cut state according to the same manufacturing method. DETAILED DESCRIPTION OF THE INVENTION

[0021] A die-casting manufacturing method and apparatus according to an embodiment of the present invention will be described in detail below with reference to the drawings. Note that the following description is merely one embodiment, and various modifications may be made to the present invention as long as they do not deviate from the spirit of the present invention.

[0022] 1 and 2 show a cross-sectional view and a side view of the main parts of a die-casting production apparatus according to this embodiment. The die-casting production apparatus comprises a movable die 12 attached to a movable platen and a fixed die 14 attached to a fixed platen, and molten metal is injected into a cavity 16 formed by bringing the two dies 12, 14 into contact, thereby completing a product having a shape that conforms to the cavity 16. The product can be removed from the cavity 16 by separating the dies 12, 14 and operating an ejector pin provided on the back surface of the movable die 12.

[0023] A molten metal supply means is disposed below the cavity 16 as an injection section for supplying molten metal to the cavity 16 of such a die-casting manufacturing device. This is composed of a first pressurizing means 22 consisting of an injection sleeve 18 that is attached by penetrating horizontally through the fixed platen and reaches the fixed mold 14, a plunger 20 disposed within the injection sleeve 18, and a pressurizing device that is located behind the plunger 20 and can push and pull the plunger 20.

[0024] A runner 24 is formed at the front end of the injection sleeve 18, serving as a passageway leading to the cavity 16. This runner 24 is made up of a diverter runner 26 that extends almost horizontally from the injection sleeve 18 and gradually narrows in cross section, and a rising runner 28 that turns upward so as to connect directly to the bottom of the cavity 16. The molten metal extruded by the plunger 20 passes through the diverter runner 26, is turned upward by the rising runner 28, and is injected and sprayed into the cavity 16.

[0025] Such a rising runner 28 is provided with a second pressurizing means 30 that secondarily pressurizes the molten metal in the cavity 16. In this embodiment, a bent portion is formed in the rising runner 28, and the second pressurizing means 30 is provided on a runner portion 32 of this bent portion that is directly connected to the cavity.

[0026] 2, the rising runner 28 is composed of a lower horizontal runner section 34 into which the molten metal flows directly from the diverter runner 26 side, a connecting runner section 36 that rises at the tip of the lower horizontal runner section 34 parallel to the rising runner 28, and an upper horizontal runner section, i.e., a cavity-direct runner section 32, that returns to the original rising runner 28 side at the tip of the connecting runner section 36 and is parallel to the lower horizontal runner section 34, which introduces the molten metal into the cavity 16. The lower horizontal runner section 34, connecting runner section 36, and cavity-direct runner section 32 form a U-shaped bend section 38. A pressurizing pin 40 of the second pressurizing means 30 moves in and out of the cavity-direct runner section 32 to pressurize the molten metal, thereby enabling secondary pressurization.

[0027] The second pressure applying means 30 is composed of an actuator (not shown) attached to the molds 12, 14, and a pressure applying pin 40 that is moved by the actuator to protrude from the end face of the connecting runner portion 36 and move horizontally in the cavity-directly connected runner portion 32. As shown in Fig. 3, the diameter d of the pressure applying pin 40 is smaller than the inner diameter D of the cavity-directly connected runner portion 32, allowing the pressure applying pin 40 to slide left and right in the cavity-directly connected runner portion 32. Therefore, the amount V (see Fig. 3) of pressure applying pin 40 into the cavity-directly connected runner portion 32 improves the density of the product formed by the cavity 16.

[0028] In this embodiment, an orifice 42 that narrows the inner diameter is formed on the cavity-direct runner portion 32 side (part B in FIG. 2) to the right of the intersection (section AB in FIG. 3) between the connecting runner portion 36 and the cavity-direct runner portion 32 at the bent portion 38. This is an annular protrusion 44 with a rectangular cross section formed on the inner diameter portion of the cavity-direct runner portion 32, and the height of the protrusion 44 (i.e., the inner diameter dimension of the cavity-direct runner portion 32) is matched as closely as possible to the outer diameter d of the pressure pin 40 so that a metal seal can be formed here. Specifically, although this depends on the size of the cavity 16, the gap dimension Δ is half the difference between the inner diameter D of the cavity-direct runner portion 32 and the outer diameter d of the pressure pin 40, and the height of the annular protrusion 44 is determined so that the gap dimension Δ is 1 / 2 to 1 / 3 or less. That is, the gap dimension δ of the metal seal portion is 1 / 2 of the difference between the inner diameter of the annular protrusion 44 and the outer diameter d of the pressure pin 40, where δ = Δ × 1 / 2, and preferably δ = Δ × 1 / 3, with the lower limit being the value at which the metal seal breaks. Also, the axial length L of the annular protrusion 44 is set to about 10 mm to ensure a reliable metal seal.

[0029] The second pressurizing means 30 configured in this manner starts pressurizing from the position shown in Figure 4(1) after injection by the plunger 20 of the first pressurizing means 22 is completed, and when the pressurizing pin 40 reaches the annular protrusion 44, the molten metal from above enters the orifice 42 portion, forming a metal seal (Figure 4(2)), which performs a shielding function at that portion. Therefore, the metal seal at this orifice 42 portion increases the amount of molten metal filled into the cavity 16, and the pushing action of the pressurizing pin 40 lengthens the stroke, completing the operation (Figure 4(3)).

[0030] The annular protrusion 44 forming the orifice 42 may have a rectangular cross section as in the embodiment, but it may also have a V-shaped or arc-shaped cross section. In this case, if the tip of the V-shaped or arc-shaped protrusion is sharp, it will be difficult to remove the metal seal, so it is desirable to have a shape with the tip cut off.

[0031] Furthermore, a cooling means can be placed on the annular protrusion 44 that forms the orifice 42. This can be a horizontal water-cooling type or an oil-cooling type, and it is advisable to cool it when injection by the first pressurizing means 22 is completed and pressure is applied to the annular protrusion 44 by the second pressurizing means 30 (Fig. 4(2)). This makes it easier to form a metal seal.

[0032] In the above embodiment, the annular protrusion 44 that forms the orifice 42 may be formed as a separate part and attached by a fitting structure when forming the runner 24. This is because the runner 24 is structured to split at the parting line of the mold, making it easy to attach to the rising runner 28, which has a semicircular structure. The above embodiment can also be applied to pushing a runner in a hot chamber and when molding plastics.

[0033] As described above, according to this embodiment, injection into the cavity 16 is performed by the first pressurizing means 22, and the second pressurizing means 30 is activated when the runner 24 is filled with molten metal. The pressurizing pin 40 performs a normal extrusion action while reaching the intersection (FIGS. 3A-3B) of the connecting runner portion 36 and the cavity-directly connected runner portion 32. However, as soon as the connecting runner portion 36 ends and the runner portion 32 is reached, the annular protrusion 44 solidifies the molten metal by the metal seal in the gap δ, and the pressure is shut off (FIG. 4(2)). Therefore, the unsolidified molten metal in the runner on the cavity 16 side, located above the pressurizing pin 40, is pushed toward the cavity 16 against the backdrop of the shut-off pressure.

[0034] This allows the pressure pin to be advanced by a greater stroke than in the past (Fig. 4(3)), and a denser product can be manufactured by the second pressure means 30. The effect of this is that when molten metal is filled into a cavity 16 of the same volume, the weight increases by 1.7%, which is an astonishing value in this industry.

[0035] In particular, in this embodiment, a U-shaped bend 38 is provided in the rising runner 28, and the second pressure applying means 30 is attached to the cavity direct connection runner portion 32, which is a passage leading to the cavity 16. Therefore, the second pressure applying means 30 can be positioned to avoid the cooling means attached to the thick biscuit 46, core, etc., thereby increasing the degree of freedom in design.

[0036] Next, Figure 5 shows a second embodiment. While the bent portion of the previous embodiment was U-shaped, this embodiment uses a V-shape. The runner 24, particularly the rising runner 28, of the runner 24 connecting the first pressurizing means 22 and the cavity 16 is bent into a V-shape. The runner 24 comprises a first inclined runner section 50 whose base end leads to the first pressurizing means 22, and a second inclined runner section 52 connected to the first inclined runner section 50 and directly connected to the cavity 16. The second inclined runner section 52 is fitted with a second pressurizing means 30 equipped with a pressurizing pin 40 that can slide back and forth along its axis. An orifice 42 is provided on the second inclined runner section 52 side of the intersection of the inclined runner sections 50 and 52 to reduce its inner diameter. A metal seal is formed between the orifice 42 and the pressurizing pin 40 of the second pressurizing means 30 to prevent backflow of molten metal while the second pressurizing means 30 applies pressure. The other configurations are the same as those in the above embodiment, so the explanation will be omitted.

[0037] In this embodiment, the rising runner 28 serving as the pressurizing path is provided with a V-shaped bent portion 54, so that the pressure is applied in an oblique direction, but even with this configuration, the cooling means can be avoided, and the degree of freedom in design is increased.

[0038] Next, Figure 6 shows an example of application to the "center gate manufacturing method." The "center gate manufacturing method" is applied to circular or conical shaped parts and point-symmetric parts, and is used to fill the molten metal from the center of the cavity 5 to improve the filling balance.

[0039] As shown in FIG. 6, the center gate molding method is performed in an apparatus having a second movable mold 64 disposed 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. A spool 70 is formed in the second movable mold 64, connecting the cavity 66 to a runner 68. The spool 70 is conical, with its apex located at the center of the circular cavity 66. By supplying molten metal from the apex, the molten metal is distributed throughout the cavity 66 through the spool 70. The runner 68 is formed on the mating surface of the fixed mold 60, bends at a right angle from the apex of the spool 70, and extends downward. The runner 68 is connected to a horizontally extending plunger sleeve 72 disposed below the fixed mold 60. A plunger 74 is inserted into the plunger sleeve 72, and a primary pressure is applied by an actuator (not shown) to inject the molten metal. The pressurizing means including this plunger 74 is the first pressurizing means 76. In addition, a gate cutting hydraulic cylinder 78 that faces the runner 68 is provided on the mating surface between the fixed mold 60 and the second movable mold 64, and when the molds are opened, this gate cutting hydraulic cylinder 78 cuts and separates the runner 68 from the spool 70.

[0040] A second pressure means 80 is provided on the fixed mold 60 side, facing the apex of the spool 70. This means comprises a pressure cylinder 82 and a pressure pin 84 that moves in and out of the pressure cylinder 82. The pressure pin 84 moves in and out toward the apex of the spool 70 formed in the second movable mold 64. Specifically, as shown in the enlarged portion of FIG. 6 , a curved passage 86 provided at the point connecting the runner 68 and the spool 70 serves as the passage for the pressure pin 84 to enter and exit. This passage is formed inside the second movable mold 64 and connects to the cavity 66. The pressure pin 84 crosses the runner 68 and pressurizes the cavity 66 upon reaching the curved passage 86. A circular ring 88 is attached to the curved passage 86, forming an orifice 90 that narrows its inner diameter. This orifice 90 has a rectangular cross-section and is formed on the inner diameter of the curved passage 86. The height of this protrusion is adjusted as closely as possible to the outer diameter d of the pressure pin 84, allowing a metal seal to be formed here. Therefore, as shown in the enlarged view of FIG. 6 (the view at the bottom of the same figure), the amount of pressure applied by the pressure pin 84 is the amount of pressure applied to the cavity 66.

[0041] The actual process of this "center gate manufacturing method" is shown in Figures 7 to 12. First, with the mold clamped, the first pressurizing means 76, the gate-cutting hydraulic cylinder 78, and the second pressurizing means 80 are also in standby. First, molten metal is poured through the inlet of the plunger sleeve 72 (Figure 7). After pouring is complete, the first pressurizing means 76 begins operation, moving at high speed and completing the low-speed, high-pressure injection at its forward limit. The molten aluminum enters the runner 68, rises, passes through the curved passage 86, and is filled into the cavity 66 from the spool 70 (Figure 8). 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 the pressurizing pin 84 from the standby position of the second pressurizing means 80 (top view of the enlarged view in Figure 6) using the pressurizing cylinder 82. The molten aluminum then crosses the runner 68 and reaches the curved passage 86. The molten aluminum from the upper part enters the orifice 90, forming a metal seal, which provides a shielding function. Therefore, the metal seal at this orifice 90 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 process (Figure 9). Next, the first movable mold 62, including the second movable mold 64, moves back, and one side of the intermediate mold is opened. This brings the runner 68 into contact with the cavity 66 (Figure 10). In this mold-open state, the gate-cutting hydraulic cylinder 78 is operated to cut and remove the runner portion (Figure 11). Finally, the first movable mold 62 is moved back further, widening the gap between the second movable mold 64 and the first movable mold 62 of the intermediate mold, and the product is removed from the cavity 66, completing the process (Figure 12).

[0042] Thus, according to the "center gate manufacturing method," the second pressurizing means 80 and orifice 90, which pressurize the spool 70 located in the center of the cavity 66, form a metal seal due to their throttling effect, blocking backflow and maintaining pressure, thereby enabling additional pressure to be applied to the product. This eliminates the need to place the second pressurizing means 80 below the runner 68, eliminating the need for the second pressurizing means 80 to get in the way. Furthermore, the installation of the orifice 90 allows for the thickness of the cylindrical thick-walled portion connecting the runner 68 and the spool 70 to be adjusted, enabling the thickness to be set to facilitate punch cutting by the gate-cutting hydraulic cylinder 78. While the gap Δ is proportional to the gap length L of the orifice 90, determining the gap length L of the orifice 90 to thin the gap Δ to a strength that allows for easy cutting provides other benefits, such as easier cutting. [Industrial Applicability]

[0043] The present invention provides a method and apparatus for die casting production in which, following plunger pressure from a first pressure means, pressure is applied to the runner portion in "normal die casting methods" and the spool portion in "center gate methods" using a second pressure means, thereby improving product density.In addition, in "normal die casting methods," the second pressure means can be positioned so as not to interfere with cooling means such as biscuits, and in "center gate methods," it is installed in a fixed mold, which is easy to install. [Explanation of symbols]

[0044] 1...Fixed mold, 2... Movable mold, 3...first pressurizing means, 4... second pressurizing means, 5...cavity, 6...Runner, 7...Pressure pin, 8...Orifice, 9...Second movable mold, 10...spool, 11...gate cutting cutter, 12... Movable mold, 14...Fixed mold, 16...cavity, 18....Injection sleeve, 20...plunger, 22...first pressurizing means, 24...Runner, 26...Divider Runner, 28...standing runner, 30...second pressurizing means, 32... Runner section directly connected to the cavity (upper horizontal runner section), 34...Lower horizontal runner section, 36...Connecting runner section, 38...U-shaped bent part, 40...Pressure pin, 42...Orifice, 44...annular protrusion, 46...biscuits, 50...First inclined runner section, 52...Second inclined runner section, 54...V-shaped bent part, 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...pressurized cylinder, 84...Pressure pin, 86...bent passage, 88...Circular ring, 90...Orifice.

Claims

1. A die casting manufacturing method characterized in that, after molten metal is injected into a clamped mold by a first pressurizing means, a second pressurizing is performed by a second pressurizing means through a runner directly connected to the cavity, the runner is bent, the second pressurizing means is provided in the runner section directly connected to the cavity at this bent part, and an orifice is arranged, and pressurization is performed by the second pressurizing means while preventing backflow of molten metal at the orifice section by a metal seal between the pressurizing pin of the second pressurizing means and the orifice section.

2. 2. The die casting manufacturing method according to claim 1, wherein the bent portion is formed in a U-shape.

3. 2. The die casting manufacturing method according to claim 1, wherein the bent portion is formed in a V-shape.

4. a first pressurizing means for injecting molten metal into a die-casting mold; a second pressurizing means for bending the runner communicating with the cavity and for applying pressure in the direction of the cavity, the second pressurizing means being provided at the bent portion of the runner directly connected to the cavity; an orifice that is provided in a pressurizing path by a pressurizing pin of the second pressurizing means and that can shield the molten metal between the pressurizing pin and the orifice; A die-casting manufacturing device characterized by having an injection section comprising:

5. 5. The die-casting manufacturing apparatus according to claim 4, wherein the bent portion is U-shaped.

6. 5. The die-casting manufacturing apparatus according to claim 4, wherein the bent portion is V-shaped.

7. In a center gate manufacturing method, a first pressurizing means for injecting molten metal into a clamped mold cavity through a runner and a spool; a second pressurizing means provided in a fixed mold, facing the spool and pressurizing the molten metal after the first pressurizing means pressurizes the molten metal; A die casting manufacturing apparatus characterized in that an orifice is provided in a passage provided in a bent portion of the runner leading to a spool, and pressurization is performed by the second pressurizing means while preventing backflow of molten metal at the orifice portion by a metal seal between the orifice and the pressurizing pin of the second pressurizing means.

8. The die casting manufacturing apparatus according to claim 7, characterized in that in the center gate manufacturing method, the spool portion changes from solid to cylindrical by applying pressure to the runner, making it easier to cut with a punch using a hydraulic cylinder.

9. In a center gate manufacturing method, a first pressurizing means for injecting molten metal into a clamped mold cavity via a runner and a spool that communicates with the mold cavity via a bent portion at the tip of the runner; a second pressurizing means disposed in the fixed mold opposite the spool; A die casting manufacturing apparatus characterized in that the pressure pin of the second pressure means is capable of moving in and out of a bent portion installed in the spool portion, and a pressure pin is provided between the bent portion and an orifice provided in this bent portion and prevents backflow of molten metal by a metal seal, thereby pressurizing the spool portion.

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