Mold-release agent spray mechanism, metal mold, and mold-release agent applying method

Abstract

To provide a die-cast device, a metal mold, and a mold-release agent spray mechanism provided in the device, which can appropriately apply a mold-release agent to a surface of a metal mold even if the metal mold is formed in a complicated shape having an inner metal mold.SOLUTION: A mold-release agent spray mechanism 23, which is provided in a die-cast device provided with a pair of metal molds 20 that mold an outer shape of a molded article and an inner metal mold 20c, positioned inside the metal mold, which molds an inner shape of the molded article, can apply a mold-release agent to a hidden surface O of the inner metal mold that is hidden from respective mold-opened surfaces P of the pair of metal molds which appear when mold-opening the pair of metal molds and comprises a mold-release agent suction port 24, a mold-release agent blow-out port 26 and a mold-release agent passage 25 through which the ports communicate with each other. The mold-release agent passage has a Venturi tube structure and is formed so that the mold-release agent blow-out port is shorter than the mold-release agent suction port across a position E where a length of the mold-release agent passage becomes an extremal value. The mold-release agent suction port opens to a surface other than the hidden surface of the mold-opened surface of the mold-release agent suction port, and the mold-release agent blow-out port opens to oppose to the hidden surface.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a technique relating to a die casting apparatus and a method for applying a release agent to a die of the die casting apparatus. [Background technology]

[0002] Die casting is a casting technique that allows for the mass production of castings in a short time by forcing molten metal such as aluminum alloy, zinc alloy, magnesium alloy, or copper alloy into a die. The resulting die-cast molded products (hereinafter referred to as "molded products") have excellent dimensional accuracy, beautiful and smooth casting surfaces, and can be formed into complex shapes and thinned, so they are primarily used to manufacture products in the automotive, electrical, electronic, and optical fields.

[0003] In the production process of plastic products, techniques using molds such as injection molding are also known, and the process of "melting" the raw material → "pouring" → "solidifying" → "removing" is the same for both die casting and plastic molding. However, there are two major differences between the two technologies: "melting" and "pouring". In the "melting" process, die casting melts the metal to a temperature where it does not easily solidify, so the melting temperature is about twice as high as melting plastic. In the "pouring" process, due to the difference in viscosity of the material, the raw material is poured in a "syrup-like" state in plastic molding, whereas it is poured in a "water-like" state in die casting. In addition, considering that metal has high thermal conductivity and is easily solidified, the "pouring" speed must be measured in mm / sec in plastic molding, whereas it must be measured in m / sec in die casting.

[0004] Therefore, die casting machines are different from plastic molded product manufacturing machines in many ways. The applicant has been continuing technological development for die casting machines for a long time, and has developed technologies related to die casting machines, for example, as described in JP 61-259864 A (Patent Document 1), JP 59-102250 A (Patent Document 2), JP 2021-007965 A (Patent Document 3), etc. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 61-259864 [Patent Document 2] Japanese Utility Model Application Publication No. 59-102250 [Patent Document 3] Patent Publication No. 2021-007965 Summary of the Invention [Problem to be solved by the invention]

[0006] In the manufacturing of products using die casting technology, when various molten metals flow into a molding die, the heat of the molten metal is absorbed by the die, and it is rapidly cooled and solidified to form the molded shape. Therefore, since the molding die is easily damaged by the sudden change in temperature, it is necessary to avoid as much as possible the failure to eject the molded product, which can easily damage the molding die.

[0007] In order to solve these problems and ensure that the molded product can be stably removed from the mold, a mold release agent is generally applied to the mold surface. The release agent plays the role of ensuring lubrication for stably extracting the molded product from the die, preventing seizure on the die, and cooling the die. By adhering a certain amount to the die surface, the lubrication, protection, and cooling properties are ensured. The adhesion of the release agent to the die surface means that the oil in the release agent remains on the die surface as a lubricating oil film. Since most of the general release agents are water-soluble release agents, it is necessary for the water, which is the solvent, to evaporate and for the oil to remain. Therefore, if the die temperature is low, the water, which is the solvent, does not evaporate sufficiently, and the lubricating oil flows down and the release agent does not exert its effect. On the other hand, if the die temperature is too high, the release agent itself floats due to the riding frost effect caused by the evaporation of water, and the release agent components do not adhere. Therefore, although the application of the release agent is a seemingly simple technique, it is not easy to adhere the required amount of the release agent to the die surface. The temperature range at which the release agent particles can reach the die surface is called the wetting temperature or the release agent adhesion temperature.

[0008] There are various types of release agent spray devices for applying the release agent to the mold surface, and articulated robot spray devices and electrostatic spray devices have been developed, but they are all expensive and have not become established, so general spray devices are often used. However, when the molded product has a complex shape, the mold parts overlap each other, creating blind spots, which makes it difficult to apply the release agent. This will be explained in detail below.

[0009] Fig. 16 shows a simple mold K1 for manufacturing a solid molded product, for example, the cylindrical product 1 shown in Fig. 16(C). The mold K1 is composed of a pair of molds, a fixed mold K1a and a movable mold K1b, as shown in the side end view of Fig. 16(A), and in the state shown in Fig. 16(B) where the movable mold K1b is aligned with the fixed mold K1a, i.e., in the mold clamped state, the cylindrical product 1 is formed as a molded product conforming to the shape of the cavity V.

[0010] Fig. 17 shows a simple mold K2 for manufacturing a hollow molded product, for example, a cylindrical product 2 shown in Fig. 17(C). As shown in the side end view of Fig. 17(A), the mold K2 has a pair of molds, a fixed mold K2a and a movable mold K2b, like the mold K1, but also has an inner mold K2c that models the internal shape of a cylinder. In the mold clamping state shown in Fig. 17(B) where the fixed mold K2a and the movable mold K2b are fitted together with the inner mold K2c sandwiched between them, a cavity V that represents the product shape is formed between the fixed mold K2a, the movable mold K2b, and the inner mold K2c, and a cylindrical product 2 is formed as a molded product.

[0011] For ease of explanation, only the arrangement of the inner mold K2c is shown in the mold K2 shown in Figure 17, but in practice, it is preferable that the inner mold is arranged in a fixed mold and configured to be movable over the fixed mold.

[0012] Thus, the mold K3 shown in Fig. 18 is a mold for manufacturing a cylindrical product 3 like the mold K2 shown in Fig. 17, but the inner mold is configured to be movable on the fixed mold. That is, in the fixed mold K3a, as shown in Fig. 18(A), a pin holding part 5 is formed that allows a slide pin 4, which becomes the inner mold K3c, to move in and out of the cavity V. On the other hand, in the movable mold K3b, a groove 6 for accommodating the pin holding part 5 and the slide pin 4 is formed.

[0013] The pin holding portion 5 can move from above the fixed mold K3a as shown in Fig. 18(A) to below the fixed mold K3a as shown in Fig. 18(B), and when the mold is clamped, the slide pin 4 is placed inside the cavity V. Then, in the clamped state shown in Fig. 18(C), the cavity V that bears the product shape is formed between the fixed mold K3a, the movable mold K3b, and the slide pin 4 that is the inner mold K3c, and a cylindrical product 3 shown in Fig. 18(D) is formed as a molded product.

[0014] Fig. 19 shows a state in which a release agent is applied to the surface of the cavity V that appears at the mold opening surface P when the mold K3 shown in Fig. 18 is opened. A tube pipe 31 extends from the mold release agent spray device 30, and the release agent L is sprayed from the tip of this tube pipe 31 onto the surface of the cavity V. After the release agent L has been sprayed, the tube pipe 31 rises so as not to interfere with the movement of the movable mold K3b when it is clamped.

[0015] Fig. 20 is a view of the mold K3 from the mold opening surface P when the mold K3 shown in Fig. 18 is opened. Fig. 21 is a cross-sectional view of the line XXI-XXI in Fig. 20. As can be seen from these figures, when the release agent L is applied in a state where the movable mold K3b is opened relative to the fixed mold K3a, the release agent can be applied to the surfaces of the cavity V of the fixed mold K3a and the movable mold K3b. However, for the slide pin 4, which is the inner mold K3c, the release agent L is applied to the surface F facing the pipe 31, but the back surface H, i.e., the shadow surface O relative to the mold opening surface P, is a blind spot, so the release agent L cannot be applied sufficiently. Note that in Fig. 20, the part that represents the shape of the molded product is indicated by a cross-hatched line.

[0016] Therefore, an object of the present invention is to provide a die casting machine that can suitably apply a release agent even when constructing a complex die for producing a hollow molded product, and a release agent spraying mechanism and die that are provided in the die casting machine. [Means for solving the problem]

[0017] In order to solve the above problems, the present disclosure has the following configuration.

[0018] That is, the present disclosure relates to a release agent spraying mechanism provided in a die casting apparatus which has a pair of dies which represent the external shape of a molded product, and an inner die which is located inside the dies and which represents the internal shape of the molded product, and which is capable of applying a release agent to a shadow surface of the inner die which is in the shadow of each of the die opening faces which appear when the pair of dies are opened, and which has a release agent suction inlet, a release agent outlet, and a release agent passage which communicates between the two, the release agent passage having a Venturi tube structure and which is formed such that the release agent outlet side is shorter than the release agent suction inlet side across a position where the length of the release agent passage is at its extreme value, the release agent suction inlet opening on a surface other than the shadow surface such as the die opening face, and the release agent outlet opening opposite the shadow surface.

[0019] The present disclosure relates to a release agent spraying mechanism provided in a die casting machine having a pair of dies which represent the external shape of a molded product, and an internal die which is located inside the dies and represents the internal shape of the molded product, the mechanism being capable of applying a release agent to a shadow surface of the internal die which is shaded from each of the opening surfaces of the pair of dies which appears when the pair of dies are opened, the mechanism having a release agent suction port, a release agent outlet, and a release agent passage which communicates between the two, the release agent passage having a Venturi tube structure, and a position where the length of the release agent passage is an extreme value of the release agent passage, The release agent passage is formed so that the release agent outlet side is shorter than the release agent suction inlet side, the release agent suction inlet opens on a surface other than the negative surface such as the mold opening surface, and the release agent outlet opens opposite the negative surface, so that even in a die casting machine equipped with a complex mold having an internal mold, it is possible to suitably apply the release agent to the negative surface of the internal mold (rear surface, etc.) by simply applying the release agent from the mold opening surfaces of both the fixed mold and the movable mold using a normal release agent application device (release agent spray device). Therefore, it is possible to sufficiently apply the release agent to the mold, not only to prevent omissions in the application of the release agent, but also to reduce damage to the mold and the production of defective products.

[0020] The present disclosure relates to a release agent spraying mechanism, in which at least one of the pair of molds has a recess for accommodating the inner mold, and the recess is provided with the release agent outlet. The present disclosure provides a release agent spraying mechanism in which at least one of the pair of dies has a recess for accommodating the inner die, and the recess is provided with the release agent outlet. This makes it possible to sufficiently apply the release agent to the negative side of the die, which is normally difficult for the release agent to reach. To explain in more detail, even when a mold is used in which the inner mold does not enter the fixed mold or the movable mold when the release agent is released, the release agent is difficult to reach and adhere to the shadow surface of the inner mold. However, when the inner mold enters the inside of the fixed mold or the movable mold, the release agent is even more difficult to adhere to the shadow surface of the inner mold. Even in such a case, the release agent can be suitably adhered to the shadow surface of the inner mold because the release agent spraying mechanism is provided. Moreover, because a release agent outlet is provided in the recess, it is easy to design the length of the duct on the outlet side of the release agent passageway to be shorter than the length on the inlet side of the release agent.

[0021] The present disclosure relates to a release agent spraying mechanism having a recess for accommodating the inner mold in at least one of the pair of molds, the recess having a shape that conforms to the surface shape of the inner mold, and the recess having the release agent outlet. The present disclosure provides a release agent spray mechanism in which at least one of the pair of dies has a recess for accommodating the inner die, the shape of the recess conforms to the surface shape of the inner die, and the recess is provided with the release agent outlet, so that the release agent can be sufficiently applied to the negative side of the release agent that is usually difficult for the release agent to reach. In addition, when air is released from the release agent outlet, the spread of the air is suppressed so that the air can easily flow along the negative side of the inner die, so that the moisture from the release agent can be suitably evaporated.

[0022] The present disclosure relates to a release agent spraying mechanism, which has a recess in at least one of the pair of dies for accommodating the inner die, and which has a diffusion chamber that is a portion formed by further recessing the surface of the recess, and which is provided with the release agent outlet in the diffusion chamber. The present disclosure provides a release agent spray mechanism in which at least one of the pair of dies has a recess for accommodating the inner die, the recess has a diffusion chamber which is a portion formed by further recessing the surface of the recess, and the diffusion chamber is provided with the release agent outlet. This makes it possible to provide a required distance from the release agent outlet to the rear surface of the inner die, and therefore a sufficient distance can be secured for the dispersion of the release agent.

[0023] The present disclosure relates to a release agent spraying mechanism in which the release agent outlet and the release agent suction inlet are open in the same direction, and the release agent outlet is opened on the farther side than the release agent suction inlet when viewed from the front of the mold opening surface. In the present disclosure, the release agent spray mechanism has a release agent outlet and a release agent suction port that open in the same direction and that open further back than the release agent suction port when viewed from the front of the mold open surface. This makes it possible to make the length of the conduit on the outlet side of the release agent passage shorter than the inlet side, and makes it possible to discharge the release agent without impairing the blowing strength of the release agent from the release agent outlet.

[0024] The present disclosure relates to a release agent spraying mechanism, in which the release agent outlet is formed by a replaceable spray nozzle at an end of a release agent passage. In the present disclosure, the release agent outlet is a release agent spray mechanism formed by a replaceable spray nozzle at the end of the release agent passage, so that the spread of the release agent discharged from the release agent outlet and the amount of the release agent that hits per unit area of ​​the inner mold surface can be adjusted, and the release agent can be made to adhere appropriately according to the surface shape of the inner mold. Moreover, by simply changing the release agent outlet, the spread of the release agent and the amount of the release agent that hits can be adjusted without changing the other parts of the release agent passage.

[0025] The present disclosure relates to a release agent spraying mechanism, in which the release agent outlet is formed by a replaceable spray nozzle at an end of a release agent passage, and the spray nozzle is provided with a wide-angle nozzle having a plurality of openings at positions equally spaced apart from the center, or a flat spray nozzle having a flat opening. In the present disclosure, the release agent outlet is formed by a replaceable spray nozzle at the end of the release agent passage, and the spray nozzle is provided with a wide-angle nozzle having a plurality of openings at equal intervals from the center or a flat nozzle having a flat opening. Therefore, compared with the typical circular shape of the outlet of the release agent from a release agent spray device, a wide-angle nozzle can release the release agent over a wide area, and a flat nozzle can release the release agent over a flat area. This makes it possible to prevent the release agent from leaking even when the internal shape and structure of the mold are special.

[0026] The present disclosure is a release agent spraying mechanism formed as a block part that can be incorporated into either of the pair of molds. The present disclosure provides a release agent spraying mechanism that is formed as a block part that can be incorporated into either of the pair of dies. This allows the release agent spraying mechanism to be easily manufactured. It is possible to mount only the release agent spraying mechanism on the die, while leaving the precise die surface that forms the cavity surface of the product intact. It is therefore possible to mount various release agent spraying mechanisms on dies having the same cavity surface in an interchangeable manner.

[0027] The present disclosure may provide a mold including the above-described release agent spraying mechanism. Since the present disclosure provides a mold having the above-mentioned release agent spraying mechanism, it is possible to obtain a mold that can suitably apply a release agent even to the shadow surface of the inner mold.

[0028] The present disclosure relates to a die casting apparatus including a pair of dies which represent the external shape of a molded product, an internal die which is located inside the dies and represents the internal shape of the molded product, and a mechanism for spraying a release agent, the method comprising discharging a release agent from a tube of a release agent spray device to the pair of dies and the internal die and applying the release agent to the pair of dies and the internal die, the method comprising attaching a tube to the tip of the tube which is deformable when it hits a protrusion protruding from the mold opening surface when the release agent spray device is moved to a position where the release agent can be applied to each of the mold opening surfaces of the pair of dies which are revealed when the pair of dies are opened, the release agent is moved to a release agent application position, a release agent is released from a tube of the release agent spray device, and the release agent is applied to the pair of mold surfaces and the surface of the inner mold, and the release agent is also injected from the tube to which the tube, which returns to its original shape even if it is deformed, into a release agent suction port that opens onto the mold opening face, and the release agent is released through the release agent spray mechanism from a release agent outlet that opens onto a face opposite to the negative face of the inner mold, which is in the shadow of the mold opening face, thereby applying the release agent to the negative face of the inner mold.

[0029] The present disclosure relates to a method for applying a release agent to a pair of dies which represent the external shape of a molded product, an internal die which is located inside the dies and represents the internal shape of the molded product, and a mechanism for spraying a release agent, the method comprising the steps of: discharging a release agent from a tube of a release agent spray device to the pair of dies and the internal die and applying the release agent to the pair of dies and the internal die; and, when the release agent spray device is moved to a position where it can apply a release agent to each of the die opening faces which appear when the pair of dies are opened, a tube which can be deformed when it hits a protrusion protruding from the die opening faces is attached to the tip of the tube, the release agent spray device is moved to a release agent application position, and the release agent is sprayed from the tube of the release agent spray device. and applying the release agent to the pair of mold surfaces and the surface of the inner mold, and also injecting the release agent into a release agent suction port that opens onto the mold opening surface from a pipe equipped with the tube that returns to its original shape even if the deformation occurs, and discharging the release agent through the release agent spray mechanism from a release agent outlet that opens onto a surface facing the negative surface of the inner mold that is in the shadow of the mold opening surface, thereby applying the release agent to the negative surface of the inner mold. Therefore, even if the pipe of the release agent spray device collides with a protrusion from the mold opening surface, the tip of the pipe can be positioned directly in front of the release agent suction port, and a sufficient amount of release agent can be injected into the release agent spray mechanism. In addition, the following items are also disclosed in relation to the above disclosure.

[0030] That is, the present disclosure relates to a die casting apparatus equipped with a pair of dies which represent the external shape of a molded product, and an inner die which is located inside the pair of dies and which represents the internal shape of the molded product, the die casting apparatus having a release agent spraying mechanism capable of applying a release agent to a shadow surface of the inner die which is shaded from each of the opening faces of the pair of dies which appears when the pair of dies are opened, the release agent spraying mechanism having a release agent suction inlet and a release agent outlet and a release agent passage connecting the two, the release agent suction inlet opening on the opening face, and the release agent outlet opening opposite the shadow surface of the inner die.

[0031] The present disclosure relates to a die casting apparatus having a pair of dies which represent the external shape of a molded product, and an internal die which is located inside the dies and represents the internal shape of the molded product, the die casting apparatus having a release agent spray mechanism capable of applying a release agent to the shadow surface of the internal die which is in the shadow of each of the opening surfaces of the pair of dies which appears when the pair of dies are opened, the release agent spray mechanism having a release agent suction port, a release agent outlet, and a release agent passage communicating between the two, the release agent suction port opening on the opening surface, and the release agent outlet opening opposite the shadow surface of the internal die, so that even in a die casting apparatus having a complicated die having an internal die, the release agent can be applied to the shadow surface (rear surface, etc.) of the internal die which is in the shadow, simply by applying the release agent from the opening surfaces of both the fixed die and the movable die using a normal release agent application device (release agent spray device). Therefore, it is possible to reduce the occurrence of missed or insufficient application of the release agent, damage to the die due to insufficient application, and the production of defective products.

[0032] The present disclosure may also provide a die casting apparatus in which the release agent spraying mechanism is formed as a block part that can be incorporated into either of the pair of dies. The release agent spraying mechanism is a part of the die casting apparatus formed as a block part that can be incorporated into either of the pair of dies. This makes it easy to manufacture the release agent spraying mechanism and to incorporate it into the die (inside the die casting body).

[0033] The present disclosure may also provide a die casting apparatus in which the release agent passage has a Venturi tube structure. Since the die casting apparatus has a Venturi tube structure for the release agent passage, the release agent passing through the release agent passage has a low degree of deceleration, and the amount of release agent remaining in the tube can be reduced. As a result, the release agent can be suitably applied to the inner die.

[0034] The present disclosure may also provide a die casting apparatus in which the release agent outlet is formed by a replaceable spray nozzle at an end of the release agent passage. Since the die casting apparatus is configured such that the release agent outlet is formed by a replaceable spray nozzle at the end of the release agent passage, the spray angle, spray amount, etc. of the release agent can be easily adjusted by replacing the spray nozzle.

[0035] The present disclosure relates to a mold comprising a pair of dies which represent the external shape of a molded product, and an internal die which is located inside the pair of dies and which represents the internal shape of the molded product, the mold comprising a release agent spraying mechanism capable of applying a release agent to a shadow surface of the internal die which is shaded from each of the opening surfaces of the pair of dies which appears when the pair of dies are opened, the release agent spraying mechanism having a release agent suction inlet and a release agent outlet and a release agent passage connecting the two, the release agent suction inlet opening on the opening surface and the release agent outlet opening opposite the shadow surface of the internal die.

[0036] The present disclosure provides a mold comprising a pair of dies which represent the external shape of a molded product, and an internal die which is located inside the pair of dies and represents the internal shape of the molded product, the mold comprising a release agent spray mechanism capable of applying a release agent to the shadow surface of the internal die which is shaded from the respective mold opening surfaces of the pair of dies which appear when the pair of dies are opened, the release agent spray mechanism having a release agent suction port, a release agent outlet, and a release agent passageway which communicates the two, the release agent suction port opening on the mold opening surface, and the release agent outlet opening opposite the shadow surface of the internal die, so that even in a complicated mold having an internal die, the release agent can be applied to the shadow surface (rear surface, etc.) of the internal die which is shaded, simply by applying the release agent to the mold opening surface when the mold is opened using a normal release agent application device. This makes it possible to reduce the occurrence of missed or insufficient application of the release agent, damage to the mold due to insufficient application, and the production of defective products.

[0037] The present disclosure relates to a method for applying a release agent to a pair of dies that represent the external shape of a molded product, and an internal die that is located inside the pair of dies and represents the internal shape of the molded product, of a die-casting machine, the method comprising the steps of: discharging a release agent onto each of the opening faces of the pair of dies that appear when the pair of dies are opened; taking in the released release agent from a release agent suction port that opens onto the opening faces; and discharging the release agent from a release agent outlet that opens onto a face that faces the negative face of the internal die, which is in the shadow of the opening faces, to apply the release agent to the negative face of the internal die.

[0038] The present disclosure relates to a method for applying a release agent to a pair of dies and an internal die of a die-casting machine having a pair of dies that represent the external shape of a molded product and an internal die that is located inside the dies and represents the internal shape of the molded product. The method is characterized in that a release agent is discharged onto each of the opening faces of the pair of dies that appears when the pair of dies are opened, the discharged release agent is taken in from a release agent suction port that opens onto the opening faces, and the release agent is discharged from a release agent outlet that opens onto a face that faces the dark side of the internal die, which is in the shadow of the opening faces, to apply the release agent to the dark side of the internal die. Therefore, even in a die-casting machine having a complicated die having an internal die, the release agent can be applied to the dark side of the internal die (rear face, etc.) that is in the shadow by simply applying the release agent from the opening faces of both the fixed die and the movable die using a normal release agent application device. Therefore, it is possible to reduce the occurrence of missed application of the release agent, damage to the die due to insufficient application, and the production of defective products. Effect of the Invention

[0039] According to the release agent spraying mechanism, the mold, and the die casting apparatus disclosed herein, even in the case of using a complex mold having an internal mold, leakage of the release agent can be prevented and the release agent can be applied to the entire surface of the mold that resembles the cavity surface. [Brief description of the drawings]

[0040] [Figure 1]FIG. 1 is a block diagram of a die casting apparatus according to the present invention. [Diagram 2] FIG. 2 is a front view showing the mold opening surface of the mold of the present invention. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2, showing a release agent spraying mechanism. [Figure 4] FIG. 2 is an explanatory diagram illustrating a Venturi structure. [Diagram 5] 5 is a cross-sectional view showing another embodiment of the recess of the mold, and corresponds to FIG. [Figure 6] FIG. 5 is a cross-sectional view showing another embodiment of the release agent spraying mechanism, which is equivalent to FIG. [Figure 7] FIG. [Figure 8] FIG. 2 is an explanatory diagram illustrating a spray nozzle. [Figure 9] 9A to 9C are explanatory diagrams illustrating one embodiment of a combination of a slide pin and a release agent spraying mechanism, in which FIG. 9A is a front view, FIG. 9B is a plan view, and FIG. 9C is a cross-sectional view of the slide pin. [Figure 10] 1 is a flowchart showing a molded product production process using a die casting device. [Figure 11] FIG. 13 is an explanatory diagram showing a mold according to another embodiment of the present invention, with the inner mold removed from the cavity. [Figure 12] FIG. 13 is an explanatory diagram showing a mold according to another embodiment of the present invention, with an inner mold inserted into the cavity. [Figure 13] The figures are schematic diagrams showing a release agent suction inlet and a release agent outlet as viewed from the front. Part (A) of FIG. 13 shows one release agent suction inlet and one release agent outlet, while Part (B) of FIG. 13 shows one release agent suction inlet with two release agent outlets branching out from it. [Figure 14] FIG. 5 is a cross-sectional view showing still another embodiment of the release agent spraying mechanism, which is equivalent to FIG. [Figure 15] FIG. 2 is a diagram showing the opening faces of various spray nozzles used in the examples and a diagram showing the size of the traces of the release agent discharged from those spray nozzles. [Figure 16]FIG. 1 is an explanatory diagram showing a conventional mold for forming a solid molded article and the resulting molded article. [Figure 17] FIG. 1 is an explanatory diagram showing a conventional mold for forming a hollow molded product and the resulting molded product. [Figure 18] FIG. 2 is an explanatory diagram showing another conventional mold for forming a hollow molded product and the resulting molded product. [Figure 19] FIG. 19 is an explanatory diagram for explaining how a release agent is applied, in which a release agent spray device is added to FIG. 18(A). [Figure 20] FIG. 19 is a front view showing the mold opening surface of the mold shown in FIG. 18. [Figure 21] FIG. 21 is a cross-sectional view taken along line XXI-XXI in FIG. 20, illustrating a state in which the release agent is applied to only one surface of the inner mold. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] The present invention will be described in more detail with reference to the embodiments. In each embodiment, the same reference numerals are used to designate parts that perform the same functions, and duplicated descriptions of the same materials, functions, effects, etc. will be omitted.

[0042] First embodiment: FIG. 1 is a block diagram showing the configuration of a die-casting machine 100 described as the present embodiment. The die-casting machine 100 has a die-casting machine body 10, a die 20, a release agent spray device 30, and a control device 50. Here, the die 20 is a separate component from the die-casting machine body 10, but the die 20 is attached to the die-casting machine body 10 and may be considered as a part of the die-casting machine body 10. In addition to these, the die-casting machine 100 may also be equipped with a vacuum device that reduces the pressure inside the cavity, an airflow introduction device that introduces or sucks airflow into the cavity, a cleaning device that cleans the die, etc., a product push-off device that removes the molded product from the die, a drop confirmation device that confirms that the molded product has been removed from the die, etc. Alternatively, in the narrow sense of the die-casting machine 100, the die-casting machine body 10 or the die 20 including the die 20 may be considered as the die-casting machine 100.

[0043] The die-casting machine body 10 can be exemplified by a hot chamber type die-casting machine body, and has roughly five units: a clamping unit 11, a melting and holding unit 12, an injection unit 13, a base unit 14, and a control unit 15. The die-casting machine body 10 is a device consisting of the basic components necessary for performing die-casting.

[0044] The clamping unit 11 clamps and opens the mold 20. The melting and holding unit 12 melts and holds the molten metal. The injection unit 13 pushes the molten metal into the mold 20 and returns the rod to its original position after injection. The base unit 14 is a frame base that supports each unit and acts as a foundation. The control unit 15 controls the devices that make up each unit.

[0045] Next, the mold will be described. Fig. 2 shows a mold 20 having a fixed mold 20a and a movable mold 20b as a pair of molds, and an inner mold 20c, and shows a mold opening surface P where the cavities V of the fixed mold 20a and the movable mold 20b of the mold 20 are seen from the front when the mold is opened. A pin holding part 21 is formed in the fixed mold 20a so that a slide pin 20c which becomes the inner mold 20c can be inserted and removed from the cavity V. Meanwhile, a groove 22 for receiving the pin holding part 21 is formed in the movable mold 20b.

[0046] Fig. 3 shows a cross-sectional view taken along line III-III of the fixed die 20a shown in Fig. 2. As shown in Fig. 3, the fixed die 20a is equipped with a release agent spraying mechanism (device) 23 having a release agent suction port 24, a release agent outlet 26, and a release agent passage 25 connecting these. The release agent suction port 24 is a portion which serves as an inlet for the release agent L. Moreover, the release agent outlet 26 is an outlet through which the release agent L taken in from the release agent suction port 24 passes through the release agent passage 25 and is blown out. In this way, the release agent spraying mechanism 23 is a series of components which provide a flow path for the release agent L inside the mold 20 so that the release agent L sprayed on the front surface F of the inner mold 20c is sprayed on the negative surface O such as the back surface H of the inner mold 20c.

[0047] The release agent suction port 24 is exposed to the mold opening surface P in the vicinity of the slide pin 20c. Since this release agent suction port 24 opens on the same surface as the surface F of the slide pin 20c, that is, on the mold opening surface P of the fixed mold, the release agent L discharged from the pipe 31 of the release agent spray device 30 toward the mold opening surface P is sprayed onto the surface of the cavity V of the fixed mold 20a, the surface F of the slide pin 20c, and the release agent suction port 24.

[0048] On the other hand, the back surface H of the slide pin 20c is a shadow surface O that is in the shadow of the slide pin 20c itself, and therefore the release agent L discharged toward the mold opening surface P has difficulty reaching it. However, since the release agent outlet 26 is exposed on the surface (opposing surface) R facing the shadow surface O of the slide pin 20c, the release agent L discharged toward the release agent suction port 24 enters this release agent suction port 24, passes through the release agent passage 25, and is discharged from the release agent outlet 26. Therefore, the release agent L that has traveled this route is sprayed onto the shadow surface O of the slide pin 20c.

[0049] When the release agent spraying mechanism 23 is provided, a normal release agent spray device 30 that discharges the release agent L from a pipe 41 can be used. By simply applying the release agent L to the front surfaces of the fixed die 20a, the movable die 20b, and the inner die 20c, the release agent L can be sprayed through the release agent passage 25 having a tunnel structure to the rear surface H of the inner die 20c.

[0050] The release agent passage 25 has a J-shaped tube shape so that the release agent L can pass through the tunnel smoothly, and preferably has a Venturi structure (or a Venturi tube structure) to improve the injection performance of the release agent L.

[0051] If the release agent passage 25 has a smooth Venturi structure, there is no wall in the passage of the release agent L that the release agent L collides with, and the release agent L can smoothly reach the release agent outlet 26, and pressure loss is unlikely to occur.

[0052] A Venturi structure is a structure that creates the Venturi effect. For example, in a pipe as shown in Figure 4 through which a flow rate Q flows, if the flow velocity at the cross-sectional area B1 is v1 and the flow velocity at the cross-sectional area B2 is v2, then the equation Q=V1·B1=V2·B2 holds true. Based on this, the diameter of the pipe is narrower on the outlet side than on the inlet side so that the flow velocity of the fluid on the outlet side is faster than on the inlet side.

[0053] That is, the release agent passage 25 is gradually narrowed toward the end, so that the pressure of the release agent L passing through the passage gradually decreases, but the flow rate increases. Therefore, when the release agent L collides with the inner mold 20c, the effect of cavitation erosion increases, and the adhesion rate of the release agent L to the inner mold 20c improves. In addition, if the release agent passage 25 is formed smooth without corners inside the pipe, the release agent is less likely to accumulate.

[0054] In contrast, when a J-shaped pipe is formed by conventional cutting using a drill or end mill, the hole can only be dug at a right angle, so the release agent passage is formed in a U-shape with two walls at right angles of 90°. Therefore, the release agent L flowing in from the release agent suction port collides twice with the walls at right angles of 90°, causing pressure loss and a decrease in flow rate. In addition, the release agent L that collides with the wall generates a backflow force, so that its momentum is reduced by the time it reaches the vicinity of the release agent outlet, and there is a risk that the release agent's ability to adhere to the inner mold 20c is hindered. In addition, the release agent is likely to accumulate at the corners.

[0055] The mechanism by which the ability of the release agent to adhere to the inner mold 20c decreases will now be described in detail. Release agent particles are made by emulsifying water and oil with a surfactant, so they have oil (the original release agent) at the core, and moisture covering the oil on the outside. Therefore, unless this moisture shell is destroyed, the oil (release agent) will not adhere to the mold and will not spread. The moisture in the destroyed particles evaporates due to the heat of the mold, and by adding a process to blow away the remaining moisture that has not completely evaporated with an air blower, the release agent can be applied properly.

[0056] The release agent passage formed by the conventional cutting process is likely to cause a decrease in the flow rate of the release agent particles, which may result in a decrease in the performance of the release agent adhesion. The reason for this is that if the injection force is reduced, it is difficult to break the moisture film even when the particles collide with the inner die 20c, and there is an increased risk that the moisture covering the particles will cause them to be repelled from the inner die, which may result in a decrease in the adhesion rate of the release agent L. In addition, there is a disadvantage that a large amount of release agent L is likely to remain in the release agent passage, which increases the need to carefully perform an air blowing process after applying the release agent.

[0057] 3, in the present mold 20 and the release agent spraying mechanism 23, the release agent outlet 26 and the release agent suction port 24 are open in the same direction, and the release agent outlet 26 is open on the inner side of the release agent suction port 24 when viewed from the front. In other words, not only are the release agent outlet 26 and the release agent suction port 24 both open to the front, but the release agent passage 25 is formed so that the length of the release agent passage 25 is shorter on the release agent outlet 26 side (outlet side) than on the release agent suction port 24 side (inlet side) across the position E where the release agent passage 25 has its extreme value.

[0058] Both the release agent suction inlet 24 and the release agent outlet 26 are open in the same direction, but their opening faces are offset and not flush, and the release agent outlet 26 is provided on the rear side in the flow direction of the release agent L at the release agent suction inlet 24. This makes it possible to increase the flow rate of the release agent L at the release agent outlet 26 compared to when the release agent outlet 26 is provided on the same plane as the release agent suction inlet 24. Therefore, in combination with the Venturi effect, a sufficient flow rate of the release agent L can be ensured at the release agent outlet 26.

[0059] The fixed mold 20a has a recess 33 for accommodating the slide pin 20c, which is an inner mold. This recess 33 is created by assembling the mold 20 so that the slide pin 20c enters the fixed mold 20a below the mold opening surface P. This structure of the mold 20 makes it easier to form the shape of the release agent passage 25 described above.

[0060] The shape of the recess 33 is preferably formed in a shape that is independent of the surface shape of the slide pin 20c as shown in FIG. 3, or in a shape that follows the surface shape of the slide pin 20c, in other words, in a corresponding shape as shown in FIG. 5. Specifically, in the mold 20 of FIG. 5, the surface of the recess 33 is semicircular in cross section in comparison with the circular cross section of the slide pin 20c. The release agent passage 25 is not only used as a passage for the release agent L in the release agent spraying step S2 described later, but also as a passage for air when air is blown in the moisture removal step S3. Therefore, if the recess 33 is formed along the surface of the slide pin 20c, the air blown out from the release agent outlet 26 has a higher contact effect with the release agent L attached to the surface of the slide pin 20c when it is discharged through the gap between the recess 33 and the slide pin 20c, and is excellent in removing moisture remaining in the mold 20. Therefore, it is preferable to form the surface shape of the recess 33 in a shape that follows the shape of the slide pin 20c.

[0061] A diffusion chamber 34 can be provided on the fixed mold 20a side near the release agent outlet 26. The diffusion chamber 34 is a portion that is recessed further from the surface of the recess 33 provided in the fixed mold 20a to accommodate the slide pin 20c, and is a portion where the release agent outlet 26 opens. If the release agent outlet 26 is provided on the surface of the recess 33 without providing the diffusion chamber 34, the released release agent L may hit the slide pin 20c before it has spread sufficiently, and the release agent L may not adhere to a wide area of ​​the slide pin 20c. For this reason, it is preferable to provide the diffusion chamber 34. On the other hand, if the distance between the surface of the recess 33 where the release agent outlet 26 opens and the slide pin 20c is widened without providing the diffusion chamber 34, there is a risk that moisture may not be sufficiently removed during air blowing in the moisture removal step S3 described later. This is because the directionality of the air released toward the slide pin 20c is weakened, and the air may spread, resulting in a poor moisture removal effect.

[0062] Another embodiment of the release agent spraying mechanism 23 and the release agent passage 25 is shown in Fig. 6. Fig. 6 is a cross-sectional view of the fixed mold, similar to Fig. 3. 6 is a suitable embodiment for cases where the slide pin 20c, which is the movable mold, penetrates deeply into the fixed mold side, and the release agent L is difficult to reach not only on the back surface H of the slide pin 20c but also on its side surface G, which become shadow surfaces O, by simply spraying the release agent L from the front surface F of the slide pin 20c. In this embodiment, a release agent outlet 26 is provided at a position facing the side surface G of the slide pin 20c, and the release agent L can be sprayed through the release agent spraying mechanism 23 not only on the back surface H of the slide pin 20c but also on its side surface G.

[0063] The release agent passage 25 shown in FIG. 6 also has a Venturi structure, and is formed so that the length of the release agent passage 25 is shorter on the release agent outlet 26 side (outlet side) than on the release agent suction inlet 24 side (inlet side) across position E, where the length of the release agent passage 25 is at its extreme value.

[0064] Since the release agent passage 25 is formed so that the side of the release agent outlet 26 is shorter than the side of the release agent suction inlet 24 across the position E, which is the extreme value of the release agent passage 25, the release agent L can be discharged without weakening the flow rate at the release agent outlet 26. Furthermore, the shape of the release agent passage 25 is not simply L-shaped from the release agent suction inlet 24 to the release agent outlet 26, but is intentionally made substantially S-shaped with a bulge, so that the release agent L can be discharged from the release agent outlet 26 without bias in the left and right directions.

[0065] It is preferable that the release agent spraying mechanism 23 is formed as a block part 27 as shown in Fig. 7. This is because it is difficult to form the precise shape of the release agent spraying mechanism 23 in the main body of the large mold 20, and it is only necessary to form an installation portion as a nesting mold in the mold 20 so that the block part 27 can be installed, and then it is only necessary to install the separately manufactured block part 27. This block part 27 can be manufactured by various methods such as metal 3D modeling, bonding, casting, etc., so that the shapes, sizes, angles, etc. of the release agent suction port 24, the release agent outlet 26, and the release agent passage 25 can be freely designed and designed, and it is also easy to process it so that another part can be attached.

[0066] The block part 27 shown in Fig. 7 has a pin housing portion 27a that houses the slide pin 20c that becomes the inner mold. This pin housing portion 27a is a portion recessed inward from the surface that defines the outer shape of the block part 27. This pin housing portion 27a is provided with a release agent outlet 26. By providing the release agent outlet 26 in the pin housing portion 27a and providing the release agent suction port 24 on the surface that defines the outer shape of the block part 27, the length of the outlet side of the release agent passage 25 is made shorter than the inlet side, and the discharge speed of the release agent L that is sprayed onto the negative surface O of the slide pin 20c can be prevented from weakening. The pin housing portion 27a may become a recess 33 of the fixed mold 20a when the block part 27 is fitted as part of the fixed mold 20a.

[0067] The block part 27 can be preferably manufactured using a metal 3D modeling printer, and plastic or metal can be used as the raw material. When manufacturing using metal, unlike plastic modeling, abrasive polishing is possible by flowing abrasive grains into the release agent passage 25, so that the block part 27 can be made into one that can vigorously spray the release agent L by polishing the rough metal surface inside the tube.

[0068] Since the release agent serves as a medium for the aqueous solution, it is necessary to prevent rust, and when assembling the block part 27 into a die, it is necessary to strictly control the dimensional accuracy of the die to be assembled and the block part 27. Since the difference in thermal expansion due to the difference in the materials of the die to be assembled and the block part 27 adversely affects the dimensional accuracy, it is necessary to select the material taking these points into consideration, and it is preferable to plate the die release agent passage 25.

[0069] As an example of a separate part that can be incorporated into the block part 27, a release agent outlet 26 can be formed as a screw-shaped spray nozzle 28, as shown in Fig. 8. If various types of spray nozzles 28 that change the application pattern of the release agent L are prepared and are structured to be attached to the release agent outlet 26, various spray patterns of the release agent L can be realized by simply replacing the spray nozzles 28, without forming several types of block parts 27.

[0070] In other words, when spraying the release agent L, the shape of the blind spot of the slide pin 20c and the positional relationship between the slide pin 20c and the release agent outlet 26 vary depending on the shape of the product to be manufactured. Therefore, even if the blind spot of the slide pin 20c has a complex shape, it is necessary to suitably apply the release agent L to the hidden surface O. By changing the spray pattern of the spray nozzle 28, it is possible to suitably apply the release agent L to the complex hidden surface O of the slide pin 20c.

[0071] The material of the spray nozzle 28 is preferably metal or plastic, and more preferably rust-resistant metal. This is because rust-resistant metal is durable and less likely to leak. More specifically, brass, copper, SUS, etc. are preferred.

[0072] Fig. 8(A) shows a perspective view of a spray nozzle 28a(28) having a circular shape of the opening 29, Fig. 8(B) shows its longitudinal cross-sectional view, and Fig. 8(C) shows a plan view of various spray nozzles 28a(28) to 28e(28) having various shapes of the opening 29. By changing the shape of the opening, it is possible to obtain a spray pattern suitable for the shape of the molded product, and also to change the flow speed of the release agent particles.

[0073] The round nozzle 28a with a circular opening 29 is a common shape and can apply the release agent L to small areas. The wide-angle nozzle 28b with multiple openings 29 can provide multiple small holes at an angle for each opening 29, and is suitable for application at a wide angle. The flat nozzle 28c with a flat opening 29 such as a rectangle is suitable for spreading and applying the release agent L in the longitudinal direction of the rectangle. The cross nozzle 28d with a cross-shaped opening 29 can apply the release agent L while taking into account the spread in the vertical and horizontal directions. And the asterisk nozzle 28e with an asterisk-shaped opening can have the characteristics of both the cross nozzle and the wide-angle nozzle.

[0074] An example of selecting a suitable spray nozzle 28 according to the shape of the slide pin 20c will be described with reference to Fig. 9. Fig. 9 shows one embodiment of a combination of the slide pin 20c and the release agent spraying mechanism 23. As shown in Fig. 9(C), the slide pin 20c described here has a U-shaped depression J in cross section, and as shown in Fig. 9(A), this U-shaped depression J continues in the longitudinal direction from the middle of the slide pin 20c to one end. Three release agent outlets 26 are provided along the longitudinal direction, and the long side of the approximately rectangular opening 29 of each flat spray nozzle 28c is arranged along the longitudinal direction of the depression J. By selecting the flat blow nozzle 28c for such a slide pin 20c and aligning the longitudinal direction of the depression J of the slide pin 20c with the longitudinal direction of the opening 29 of the flat blow nozzle 28c, the release agent L discharged through the flat blow nozzle 28c can be appropriately applied even to the inside of the depression J.

[0075] The mold release agent spray device 30 is a device for applying a mold release agent to the cavity surface of a mold as described above. A tube pipe 31 for applying a release agent to the surface extends from the mold. When the fixed mold 20a and the movable mold 20b are open, the tube pipe 31 descends from above. After the tip of the tube pipe 31 is positioned opposite the cavity V surface to release the release agent, the tube pipe 31 rises so as not to interfere with mold closing.

[0076] Such a general release agent spray device 30 can also be used when spraying the release agent L onto the mold 20 equipped with the release agent spraying mechanism 23. This is because the tip of the tube 31 of the release agent spray device 30 is directed toward the release agent suction port 24, and the release agent L is injected into the release agent suction port 24 by spraying. However, since this release agent spray device 30 basically only moves up and down, when the release agent spray device 30 is lowered and its pipe 31 is brought close to the release agent suction port 24, if the inner mold 20c protrudes from the mold opening surface P where the release agent suction port 24 is located, there is a possibility that the tip of the pipe 31 will come into contact with this protruding part. If it does come into contact, the pipe 31 will bend and it will no longer be possible to position the tip of the pipe 31 directly in front of the release agent suction port 24, and the injection of the release agent L into the release agent spray mechanism 23 will fail.

[0077] In order to solve these problems, it is preferable to attach a flexible tube made of heat-resistant silicone, polyurethane, or the like, which becomes deformable when it comes into contact with a contact object such as the inner mold 20c, to the tip of the pipe 31. By attaching such a tube, even if the tube hits a protrusion such as the inner mold 20c when the release agent spray device 30 is lowered, it will return to its original shape if it is lowered further and passes through these protrusions, making it possible to position the tip of the pipe 31 directly in front of the release agent suction port 24.

[0078] The control device 50 controls the die-casting machine body 10 and the release agent spray device 30, and also controls the vacuum device, air flow introduction device, cleaning device, drop confirmation device, and product push-off device if they are provided. The control device 50 can drive the above devices in conjunction with each other, or drive each device independently. An example of a case where independent control is performed is when a problem occurs with a die-cast molded product during the production process. In this case, all devices, including the die-casting machine body 10, are stopped, and then, when production is started again, only the release agent spray device 30 is started to check the application state of the release agent. An example of an automatic control is when the automatic operation of the release agent spray device 30 is linked to the automatic operation of the die-casting machine body 10. In this case, during the automatic operation of the die-casting machine body 10, the release agent can be automatically applied to the die 20 at the timing when the release agent needs to be applied. The control device 50 also cooperates with the control unit 15 of the die casting machine main body 10 , and the control device 50 and the control unit 15 control the entire die casting apparatus 100 .

[0079] The production of die-cast molded products follows the following steps. Figure 10 shows a flowchart of the production steps. In the initial return step S1, the movable die 20b is opened relative to the fixed die 20a, and the inner die 20c is placed in the initial position where the release agent L is suitably applied. In the next release agent spray step S2, the release agent L is sprayed from the release agent spray device 30 onto the cavity V surface of the die 20. After confirming that the application of the release agent is complete, air is blown to remove any moisture remaining in the die in the moisture removal step S3, in order to blow off any moisture remaining in the release agent outside the die. After this step is completed, in the spray device return step S4, the release agent spray device 30 is returned to its original position.

[0080] In the mold clamping step S5, the inner mold 20c is moved into the cavity V, and the fixed mold 20a, the movable mold 20b, and the inner mold 20c form a cavity surface engraved with the product shape. In the injection step S6, the casting alloy melted and held in the melting and holding unit 12 is instantly poured into the mold 20 by applying pressure using the injection unit 13. In the injection return step S7, the extruded rod is returned to its original position, and the molten metal to be cast next is replenished. Meanwhile, the molten metal injected into the mold 20 solidifies in the mold 20 and becomes the product shape, and is demolded from the mold 20 by the mold opening step S8 and the product pushing out step S9. A product pushing down device can be used for this demolding. In the drop confirmation step S10, a drop confirmation device is provided to confirm the removal of the molded product, and the process returns to the initial return step S1. This series of operations constitutes one cycle, which is one shot for producing one unit of molded product.

[0081] In the production of such molded products, mass production can be performed with good dimensional accuracy and while maintaining aesthetics. In one embodiment, the mold clamping force is set to 250KN, and one shot process can be performed in about 6 seconds. In other words, in this embodiment, 10 shots per minute, 600 shots per hour, and 8 hours of operation per day, 4800 shots can be performed per day, and if two molded products are obtained per shot, the daily production volume will be 9600 pieces. In addition to the above routine processes, other processes such as a mold cleaning process can be added as necessary.

[0082] Second embodiment: The second embodiment will be described with respect to a die-casting apparatus 200 and its die 40 capable of producing two L-shaped cylindrical molded products. Fig. 11 shows the state in which the inner die 40c (40c1-40c4) has been removed from the cavity V, and Fig. 12 shows the state in which the inner die 40c (40c1-40c4) has been inserted into the cavity V, both of which are front views of the fixed die 40a in the open state. With this die 40, two molded products can be produced on either the left or right side of the center of Fig. 11.

[0083] The inner mold 40c has four slide pins 40c1 to 40c4, with the slide pins 40c1 and 40c3 being formed to be slidable from top to bottom, and the slide pins 40c2 and 40c4 being formed to be slidable from left to right or right to left, respectively. When the movable mold 40b (not shown) is combined with the fixed mold 40a, a set of slide pins 40c1 and 40c2 and another set of slide pins 40c3 and 40c4 are combined.

[0084] Four release agent suction ports 44, 44a to 44d, are formed, and the release agent L is sprayed in the state shown in FIG. 11 where the slide pins 40c1 to 40c4 are removed from the cavity V, and the mold is clamped in the state shown in FIG. 12 where the slide pins 40c1 to 40c4 are inserted into the cavity V, and the molten metal is poured into the mold.

[0085] The die casting apparatus 200 having these molds 40 can also apply the release agent from the mold opening surface, without leaking, to the shadow surface (back surface, etc.) of the inner mold 40c which is in the shadow.

[0086] Example of modified embodiment: In the above embodiment 1, the fixed mold 20a is provided with a pin holding portion 21, and the movable mold 20b is provided with a groove 22 capable of accommodating the pin holding portion 21. However, the mold 20 may be configured not to have these portions, and the slide pin 20c may be configured to be able to be inserted and removed into the mold 20 from a pin holding portion 21 provided on the die-casting machine main body 10 other than the mold 20.

[0087] In all of the above embodiments, the release agent passage 25 is formed as a single path connecting one release agent suction port 24 to one release agent outlet 26, but the release agent passage 25 may be branched in the middle so that the release agent L is discharged from a plurality of release agent outlets 26. Fig. 13 shows a schematic diagram of the release agent suction port 24 and the release agent outlet 26 viewed from the front. In the embodiment shown in Fig. 13(A), the release agent passage 25 is a single path, whereas in the embodiment shown in Fig. 13(B), the release agent passage 25 is branched and the release agent L can be discharged from two release agent outlets 26, 26. This allows the release agent L to be applied to a wide range of the slide pin 20c.

[0088] The above embodiment is one example of the present invention, and in addition to the examples shown in the modified examples of the embodiment, modifications may be made such as substituting or adding known means or methods, and modifications are possible as appropriate within the scope that does not change the spirit of the present invention.

[0089] For example, the shapes of the slide pins shown in each figure are examples and can be appropriately made to correspond to the products to be manufactured, and the recesses 33 and pin accommodating portions 27a can be formed to correspond to the various shapes of such slide pins.

[0090] In the above description, the release agent suction port 24 of the release agent spraying mechanism 23 is opened at the mold opening surface P where the fixed dies 20a, 40a and the movable dies 20b, 40b are opened. However, depending on the arrangement of the release agent spray device 30 and the pipe 31, the release agent suction port 24 can be provided at a place other than the mold opening surface P. 14 shows an example of a release agent spraying mechanism 23 in which a release agent suction port 24 is provided on a surface different from the mold opening surface P. In this type of release agent spraying mechanism 23, the release agent passage 25 also has a Venturi structure, and is formed so that the release agent passage 25 is shorter on the release agent outlet 26 side than on the release agent suction port 24 side across a position E where the length of the release agent passage 25 is at its extreme value. EXAMPLES

[0091] Testing Method: In order to investigate the spreading of the sprayed release agent depending on the shape, size, arrangement, number, etc. of the opening (blowout port) 29 of the spray nozzle 28, spray nozzles 28 were manufactured as samples 1 to 4 having the shape shown in Fig. 15, and experiments were carried out. The details of each of the manufactured spray nozzles 28, samples 1 to 4, are as follows. All of the spray nozzles 28 were made of metal, and the distance between the opposing sides of the regular hexagonal plane was 10 mm. Sample 1 (standard nozzle): Nozzle outlet diameter: 3 mm, number of holes: 1 Sample 2 (wide-angle nozzle): nozzle outlet diameter: 2 mm, number of holes: 6, distance between the centers of two diagonal holes: 6.9 mm Sample 3 (ultra-wide-angle nozzle): nozzle outlet diameter: 1 mm, number of holes: 7, distance between the centers of two diagonal holes: 7.3 mm Sample 4 (flat nozzle): Nozzle outlet diameter: Short side length 1.5 mm, longest length 7 mm, approximately rectangular shape (longitudinal ends are semicircular), number of holes: 1,

[0092] The spray nozzles 28 of the above samples 1 to 4 were attached to the tip of a cylindrical rubber hose with an inner diameter of 6 mm and an outer diameter of 12 mm. A spray pattern measuring board (made of stainless steel) was placed vertically at a position 100 mm away from the tip of each spray nozzle 28. The release agent was injected into this rubber hose at 0.5 mL / sec, and the spread shape of the release agent sprayed from each spray nozzle 28 and formed when it hit the measuring board was observed. As a result, a spray pattern (release agent adhesion mark) with a diameter of 35 mm was formed on each measurement board for sample 1, a spray pattern with a diameter of 70 mm was formed for sample 2, a spray pattern with a diameter of 100 mm was formed for sample 3, and a spray pattern with a height of 40 mm and a width of 100 mm was formed for sample 4. In addition, the adhesion of the release agent on each measurement board after the moisture had disappeared from the release agent was sufficient for samples 1, 2, and 4, but was slightly thin for sample 3, although it could be said to pass.

[0093] Consideration: When comparing samples 1 to 3, differences were observed in the spread of the spray pattern, even though the openings were equally spaced in the 360° direction from the center of the opening 29. The spray pattern was gradually wider in sample 2 than in sample 1, and in sample 3 than in sample 2. This shows that the spray pattern is wider when the release agent outlet 26 is formed with a plurality of openings spaced apart more widely. In addition, since the release agent discharged and attached under the above conditions was satisfactory, it was found that the diameter of each opening of the spray nozzle 28 can be narrowed to 1 to 2 mm. Therefore, in the case of the slide pin 20c having a flat surface shape in which the shadow surface O is large and the sprayed release agent does not easily wrap around, it was presumed that by using a wide-angle nozzle such as that of sample 2 or sample 3 in which multiple openings are provided at equal intervals from the center, the release agent can be applied to a wide area even if the number of release agent outlets is reduced.

[0094] Comparing sample 1 and sample 4, the vertical diameter of the opening 29 of both is 3 mm for sample 1 and 1.5 mm for sample 4, which is twice the difference, but the vertical diameter of the obtained spray pattern is 35 mm for sample 1 and 40 mm for sample 4. From this, it was found that even if the shape of the opening 29 is made flat instead of circular, the amount of release agent emitted in the narrowed direction does not decrease dramatically, and a spread similar to that of a circle of the size of sample 1 can be obtained. In addition, when comparing Sample 2 and Sample 4, it was confirmed that the spray pattern areas of both were approximately the same, and therefore the position to which the release agent was to be applied could be changed by changing the shape and size of the spray nozzle 28. [Explanation of symbols]

[0095] 100,200 Die casting equipment 10 Die casting machine body 11 Clamping unit 12 Dissolution and retention unit 13. Injection unit 14 Base Unit 15 Control Unit 20,40 Mold 20a, 40a Fixed mold 20b,40b Movable mold 20c, 40c (40c1, 40c2, 40c3, 40c4) Internal mold (slide pin) 21, 41 (41a, 41b, 41c, 41d) Pin holder 22 Groove 23 Release agent spray mechanism 24, 44 (44a, 44b, 44c, 44d) Release agent suction port 25 Release agent passage 26, 46 (46a, 46b, 46c, 46d) Release agent outlet 27 Block Parts 27a Pin receiving section 28,28a~28e Spray nozzle 29 Aperture 30 Release agent spray device 31 Pipe 33 Recess 34 Diffusion Chamber 1. Cylindrical products 2,3 Cylindrical products K1 mold (mold for forming solid products) K2 mold (mold for forming hollow products) K3 mold (mold with slide pin) V Cavity L Release Agent E Location of extreme value (extremum) F surface O Hidden side (back side, etc.) H back side P type opening R Opposite surface (opposite surface) J Depression Q flow rate B1,B2 cross-sectional area v1,v2 flow velocity K1a, K2a, K3a Fixed mold K1b,K2b,K3b Movable mold K2c, K3c internal mold 4 Slide pin 5 Pin holder 6 grooves

Claims

1. A release agent spraying mechanism provided in a die casting machine having a pair of dies that model an external shape of a molded product and an inner die that is located inside the dies and models an internal shape of the molded product, A release agent can be applied to a shadow surface of the inner mold that is shaded from each of the mold opening surfaces of the pair of molds that appears when the pair of molds are opened, A release agent suction port, a release agent outlet, and a release agent passage communicating between the two, the release agent passage has a Venturi tube structure, and the release agent passage is formed such that the length of the release agent passage is shorter on the release agent outlet side than on the release agent suction inlet side, on both sides of a position where the length of the release agent passage is an extreme value of the release agent passage; a release agent spray mechanism in which the release agent suction inlet opens on a surface other than the shaded surface such as the mold opening surface, and the release agent outlet opens opposite the shaded surface.

2. 2. The release agent spraying mechanism according to claim 1, wherein at least one of the pair of dies has a recess for accommodating the inner die, and the release agent outlet is provided in the recess.

3. 2. The release agent spraying mechanism according to claim 1, wherein at least one of the pair of dies has a recess for accommodating the inner die, the recess has a shape that conforms to a surface shape of the inner die, and the release agent outlet is provided in the recess.

4. 2. The release agent spraying mechanism according to claim 1, wherein at least one of the pair of dies has a recess for accommodating the inner die, and the recess has a diffusion chamber which is a portion formed by further recessing a surface of the recess, and the release agent outlet is provided in the diffusion chamber.

5. 2. The release agent spray mechanism according to claim 1, wherein the release agent outlet and the release agent suction port are open in the same direction, and the release agent outlet is opened on the farther side than the release agent suction port when viewed from the front of the mold opening surface.

6. 2. The mechanism for spraying a release agent according to claim 1, wherein the release agent outlet is formed by a replaceable spray nozzle at an end of the release agent passage.

7. 2. The release agent spraying mechanism according to claim 1, wherein the release agent outlet is formed by a replaceable spray nozzle at an end of the release agent passage, and the spray nozzle is provided with a wide-angle nozzle having a plurality of openings at positions equally spaced apart from the center or a flat spray nozzle having a flat opening.

8. The release agent spraying mechanism according to any one of claims 1 to 7, which is formed as a block part that can be incorporated into either one of the pair of molds.

9. A mold comprising the release agent spraying mechanism according to any one of claims 1 to 7.

10. A mold comprising the release agent spraying mechanism according to claim 8.

11. A method for applying a release agent to a pair of dies which represent an external shape of a molded product, an inner die which is located inside the pair of dies and represents an internal shape of the molded product, and the release agent spraying mechanism according to any one of claims 1 to 7, comprising the steps of: discharging a release agent from a tube of a release agent spray device to apply the release agent to the pair of dies and the inner die, When a release agent spray device is moved to a position where a release agent can be applied to each of the opening surfaces of the pair of dies that appears when the pair of dies are opened, a tube that can be deformed when it hits a protrusion protruding from the opening surfaces is attached to the tip of the pipe, The release agent spray device is moved to a release agent application position, and the release agent is discharged from the tube of the release agent spray device to apply the release agent to the pair of mold surfaces and the surface of the inner mold. At the same time, the release agent is also injected into a release agent suction port opening on the mold opening surface from the tube equipped with the tube that returns to its original shape even if the deformation occurs. a release agent spraying mechanism for spraying the release agent from a release agent outlet that is opened in a surface opposed to a negative surface of the inner mold that is in the shadow of the mold opening surface, thereby applying the release agent to the negative surface of the inner mold.

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