JP2023110773A - Die cast manufacturing method and device and compression means - Google Patents

Abstract

To provide a die cast method and device which effectively prevent backflow of molten metal when performing compression of a runner after molten metal injection by a plunger, and thereby activate additional compression to a product injected into a cavity.SOLUTION: There is provided an injection part which includes: first compression means that injects molten metal to a die-casting die; second compression means that compresses a runner communicating with a cavity; and an orifice that is formed on a surface corresponding to a standing runner part directly connected to the cavity in the runner. When performing the second compression through the runner directly connected to the cavity by the second compression means after injecting the molten metal by the first compression means, the compression is performed by the second compression means while preventing the backflow of the molten metal by the orifice to a compression path of the second compression means.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a die-cast manufacturing method, apparatus and pressurizing means, and more particularly to a die-casting manufacturing method, apparatus and pressurizing means capable of simultaneously eliminating shrinkage cavities and entanglement cavities.

The method of casting a die-cast product involves pushing molten metal such as aluminum into a cavity made in a metal mold with a plunger and taking out a product that follows the shape of the cavity. The occurrence of shrinkage cavities and entrapment cavities during molding as a product constitutes a product defect, and therefore this occurrence must be suppressed.

A runner pressurization method has been proposed as a measure against shrinkage cavities in die cast products, and a PF method (Pore Free: non-porous die casting method) has been proposed as a measure against entrapment cavities.
As a countermeasure for the former, a method has been proposed in which the runner is further pressurized in accordance with the pressurizing operation of the plunger. As a countermeasure for the latter, the inside of the mold cavity is preliminarily replaced with oxygen, and the chemical reaction with the molten metal filling the cavity produces a dense product.

In the runner pressurization method, the molten metal pressurized and supplied to the cavity through the sleeve is further pressurized by a pressurizing pin on the runner portion directly connected to the cavity to perform further pressurization (Patent Document 1). . However, in this method, the molten metal pushed in by the pressurization of the runner flows back and is pushed back to the plunger side, and the desired cavity pushing effect cannot be obtained. From such a point of view, there has been developed a technique of reducing the gap between the pressurizing pin and the pressurizing passage so as to obtain a pushing effect (Patent Document 2), but it was not possible to take measures against entrapment cavities.

Also, the PF method has been proposed as a countermeasure for preventing the occurrence of entanglement cavities of defective products. As described in Patent Document 3, the inside of the mold cavity is replaced with oxygen, and the molten metal filled in the cavity is locally pressurized by a means such as a squeeze pin to produce a pressure cast product. I am trying to. However, it was not possible to take measures against shrinkage cavities.

Furthermore, Patent Document 4 discloses a combination of the conventional PF method in which oxygen is supplied from the sleeve opening and the local pressurization method within the product. Oxygen is released from the pouring port of the sleeve, and there was a problem that the oxygen concentration decreased because it was supplied from the sleeve, runner and cavity. In addition, the local pressurization method, which is used as a countermeasure against shrinkage cavities, leaves dents on the product, possibly interfering with the product's ejector pin or cooling passage.

JP 2000-117411 JP 2011-224650 JP 2019-188459 JP 2004-223610

The present invention focuses on the above problems, and can realize the PF method by supplying oxygen to the cavity without reducing the concentration, and the runner pressurization suppresses the occurrence of shrinkage cavities in the entire product. With the goal.

In order to solve the above problems, the present invention is configured as follows. When clamping the mold, the inside of the cavity is replaced with oxygen before the molten metal is injected by the plunger to prepare for the PF method, and then after the molten metal is injected by the plunger, the runner is secondarily pressurized to the molten metal at a high pressure. To provide a die-casting method and apparatus capable of producing a dense die-casting product in which entrainment cavities and shrinkage cavities are suppressed at the same time by continuously adding and solidifying.

Specifically, the method of manufacturing a die cast according to the present invention is a method of injecting molten metal from a sleeve by a first pressurizing means and then pressurizing a runner by a second pressurizing means. Oxygen can be supplied through the tip valve from the oxygen supply channel provided inside the pressurizing pin using a pin, and after the pressurizing pin of the second pressurizing means is protruded into the runner in advance, the oxygen is supplied through the tip valve. Oxygen fills and draws in the cavity, and then the runner and sleeve are also filled with oxygen. After that, the liquid is injected through the sleeve by the first pressurizing means, and then the runner pressurization is performed by the second pressurizing means. An orifice may be provided in the middle of the runner pressurizing path of the pressurizing pin of the second pressurizing means to prevent backflow of gas and molten metal.

Further, the present invention relates to a method of injecting molten metal from a sleeve by means of a first pressure means after mold clamping, and applying pressure to a runner part directly connected to a cavity by means of a second pressure means, wherein the pressure pin of the second pressure means An orifice is provided in the runner pressurizing path to prevent backflow of gas and molten metal, and the pressurizing pin of the second pressurizing means is moved to the runner side from the start of mold clamping to before injection by the first pressurizing means. While preventing backflow of gas by the orifice, oxygen is supplied back to the cavity by the oxygen supply valve provided on the pressurizing pin, and the molten metal is injected by the first pressurizing means, and then the second pressurizing means. It is characterized in that runner pressurization is performed while preventing backflow of the molten metal at the orifice.

Further, the die casting manufacturing method according to the present invention is a method in which, after clamping the mold, the molten metal is injected from the sleeve by the first pressurizing means, and the runner portion directly connected to the cavity is pressurized by the second pressurizing means, wherein the mold clamping operation, Oxygen supply operation to the cavity from the oxygen supply valve provided on the pressurizing pin of the second pressurizing means while preventing gas backflow by the orifice, retraction of the pressurizing pin, melt by the first pressurizing means through the sleeve It is characterized by performing a step of performing an injection operation and a runner pressurizing operation by a second pressurizing means such as a pressurizing pin while preventing backflow of the molten metal by the orifice.

In these cases, the pressurizing pin of the second pressurizing means has a poppet-type valve formed at the tip thereof, and this opening and closing operation opens and closes the oxygen supply passage formed in the central portion to cut off the supply of oxygen. and The orifice is formed on a surface of the runner corresponding to the runner portion directly connected to the cavity to prevent backflow of gas or molten metal.

Injection into the cavity is via a plurality of branched runners, and the orifice is formed on a surface corresponding to the rising runner portions of selected branched runners or the vicinity thereof to prevent backflow of gas or molten metal. I try to prevent it.

The moving direction of the pressing pin of the second pressing means is set to a direction crossing the plunger operating direction of the first pressing means, or a direction parallel to the plunger operating direction of the first pressing means. You can do it.
A second pressurization may be applied to the cavity via a new branch runner connected to the portion where the density improvement is desired.

In the die casting manufacturing method according to the present invention, after injecting the molten metal into the clamped mold by the first pressurizing means, when performing the second pressurization through the runner directly connected to the cavity by the second pressurizing means, the runner is an auxiliary runner provided at a place where the molten metal filled in the cavity by the first pressurizing means overflows, and after mold clamping, before injection by the first pressurizing means, the pressurizing pin of the second pressurizing means is operated to prevent backflow of gas at the orifice, oxygen is supplied back to the cavity by the oxygen supply valve provided on the pressurizing pin, and after the pressurization of the first pressurizing means is completed, the second pressurizing means is operated. The auxiliary runner pressurizes the cavity.

A die casting manufacturing apparatus according to the present invention comprises a first pressurizing means for injecting molten metal into a die casting mold, a second pressurizing means for pressurizing a runner communicating with a cavity, and a pressurizing pin of the second pressurizing means. It is composed of an oxygen supply passage formed as a hollow tube structure and the valve provided at the tip of a pressurizing pin that opens and closes the oxygen supply passage. An orifice may be provided on the surface corresponding to the runner directly connected to the cavity and through which the pressure pin is inserted.

Further, the die casting manufacturing apparatus according to the present invention corresponds to a first pressurizing means for injecting molten metal into the die casting mold, a second pressurizing means for pressurizing a runner communicating with a cavity, and a runner directly connected to the cavity. An orifice formed on the surface and through which the pressurizing pin of the second pressurizing means is inserted; and a valve for opening and closing the oxygen supply path.

In this case, the orifice is formed in the vicinity of the boundary between the diverter runner section and the rising runner section, which guides the injection of molten metal from the second pressurizing means to the cavity.

The runner consists of a plurality of branched runners, and orifices are formed on the surface corresponding to the selected branched runners, and the orifices are adapted to allow the pressurizing pin with a valve of the second pressurizing means to be inserted.
The movement direction of the pressure pin with valve of the second pressure means may be a direction crossing the direction of the plunger of the first pressure means or a direction parallel to the direction of the plunger of the first pressure means. can.
The first pressurizing means is provided with a new branch runner connected to the portion where the density is to be improved, and the second pressurizing means having a pressurizing pin with a valve that moves in the same direction as the flow of the molten metal in the new branch runner. You may make it provide.

A die casting manufacturing apparatus according to the present invention comprises first pressurizing means for injecting molten metal into a die casting mold, second pressurizing means for pressurizing a runner communicating with a cavity, and the runner being pushed into the cavity by the first pressurizing means. an auxiliary runner provided at a portion where the filled molten metal overflows, an orifice formed in the auxiliary runner on a surface corresponding to the runner directly connected to the cavity and through which the pressurizing pin of the second pressurizing means is inserted; An oxygen supply path formed inside the pressurizing pin having a hollow tube structure, a valve provided at the tip of the pressurizing pin for opening and closing the oxygen supply path, and injection by the first pressurizing means after mold clamping. The pressurizing pin of the second pressurizing means is operated before the orifice to prevent backflow of gas, and oxygen is supplied to the cavity by the oxygen supply valve provided on the pressurizing pin and returned to the first pressurizing means. and control means for controlling a series of operations for activating the second pressurizing means to pressurize the cavity from the auxiliary runner after the pressurization of (1) is completed.

The present invention is a pressurizing means for pressurizing a runner of a die casting mold, comprising a main actuator, a pressurizing pin moved in and out by the main actuator, an annular passage provided inside the pressurizing pin, and the annular passage. Consists of a poppet valve attached to the top surface of a pressurizing pin that opens and closes a passage and having a smaller diameter than the top surface, a stem shaft that operates the poppet valve and forms the annular passage, and a sub-actuator that drives the stem shaft. It is a pressurizing means characterized by being.

According to the above configuration, the inside of the cavity is replaced with oxygen by the operation of the pressure pin, and then the molten metal is secondarily pressurized while preventing the backflow of the molten metal by the pressure pin after the molten metal is injected by the plunger. The former action enables the PH method to be carried out, and the latter secondary pressurization enables the production of high-pressure, dense die-cast products. In this case, backflow of oxygen gas and molten metal can be prevented by providing an orifice formed on the surface corresponding to the runner directly connected to the cavity and through which the pressure pin is inserted. In this way, the PF method and runner secondary pressurization can be achieved simultaneously with one part, and a die-cast product that prevents the occurrence of entanglement cavities and shrinkage cavities is completed.

1 is a cross-sectional view of a main part of a die-cast manufacturing apparatus according to an embodiment; FIG. FIG. 4A is a cross-sectional view and a side view of a pressure pin used in the die-cast manufacturing apparatus; It is a hydraulic system diagram to a pressure pin. FIG. 4 is a cross-sectional view of the main part of the die casting apparatus showing the operation mode of the pressure pin; FIG. 10 is an operation mode diagram showing another modification for supplying oxygen gas. FIG. 11 is a cross-sectional view of the arrangement of a second pressurizing means according to a second embodiment; FIG. 11 is a cross-sectional view of the arrangement of a second pressurizing means according to a third embodiment; FIG. 11 is a cross-sectional view of the arrangement of a second pressurizing means according to a fourth embodiment; FIG. 11 is a cross-sectional view of the arrangement of a second pressurizing means according to a fifth embodiment;

DETAILED DESCRIPTION OF THE INVENTION A die casting manufacturing method and manufacturing apparatus according to embodiments of the present invention will be described in detail below with reference to the drawings. It should be noted that the following description is merely one example, and the present invention may include various modifications as long as the gist of the present invention is not changed.

FIG. 1 shows a cross-sectional view of a main part of a die-cast manufacturing apparatus according to the first embodiment. A die casting manufacturing apparatus 10 includes a movable mold 12 attached to a movable platen and a fixed mold 14 attached to a stationary platen, and a cavity 16 formed by bringing the two molds 12 and 14 into contact is filled with molten metal. After injection, a product having a shape that follows the cavity 16 is completed. The product can be removed from the cavity 16 by separating the molds 12 and 14 and actuating the ejector pins provided on the back of the movable mold 12 .

A hot water supply means is positioned below the cavity 16 as an injection section for supplying molten metal to the cavity 16 of the die casting manufacturing apparatus 10 . It is mounted horizontally through the fixed mold 14 and reaches the cavity 16, the plunger 20 disposed in the injection sleeve 18, and the plunger 20 behind the plunger 20. It is composed of a first pressurizing means 22 consisting of a pressurizing device (not shown) capable of pushing and pulling.

A runner 24 is formed in the front end direction of the injection sleeve 18 to serve as a passage for the molten metal to reach the cavity 16 . The molten metal pushed out by the plunger 20 of the first pressurizing means 22 passes through the flow splitter runner part 26, and the rising runner part 28 is formed so as to directly connect to the lower part. It is configured to turn upward by 28 and inject into the cavity 16 .

The rising runner portion 28 of the runner 24 is provided with a second pressurizing means 30 for secondarily pressurizing the molten metal in the cavity 16 . The second pressurizing means 30 consists of a main actuator (hydraulic cylinder) 32 provided at the bottom of the molds 12 and 14 and a pressurizing device attached so as to move in and out from the bottom to the top of the rising runner portion 28 by the main actuator (hydraulic cylinder) 32 . It is composed of a pin (actuating piston) 34 . The diameter d of the pressure pin 34 is made smaller than the inner diameter D of the rising runner portion 28 so that the pressure pin 34 can slide vertically in the rising runner portion 28 . Therefore, the amount of press fit of the pressure pin 34 into the rising runner portion 28 improves the density of the product by the cavity 16 .

By the way, in the present embodiment, the inner diameter of the rising runner portion 28 side (B portion in FIG. 2) above the intersection of the rising runner portion 28 and the shunt runner portion 26 (section AB in FIG. 2). form an orifice 36 that restricts the This is formed by forming an annular protrusion 38 having a rectangular cross section on the inner diameter portion of the rising runner portion 28. The height of the protrusion 38 (that is, the inner diameter dimension of the rising runner portion 28) is matched to the outer diameter d of the pressure pin 34 as much as possible. , so that a metal seal can be formed in those gaps. Specifically, although it depends on the size of the cavity 16, 1/2 of the difference between the inner diameter D of the rising runner portion 28 and the outer diameter d of the pressure pin 34 is the clearance dimension Δ. The height of the annular protrusion 38 is determined to be 1/2 to 1/3 or less. That is, 1/2 of the difference between the inner diameter of the annular projection 38 and the outer diameter d of the pressure pin 34 is the clearance dimension δ of the metal seal portion, and δ=Δ×1/2, preferably δ=Δ×1/3. , and the lower limit is the value when the metal seal is damaged. Further, the axial length L of the annular protrusion 38 is set to about 10 mm to ensure a metal seal.

Also, in this embodiment, as can be seen in FIG. 2, the pressure pin 34 has a stem shaft 40 axially inserted into the pin body, and an annular passage 42 is formed therein. It has a hollow tube structure that opens to the top end surface of the compression pin 34 . A poppet valve 44 having a diameter smaller than that of the pressure pin 34 is coupled to the upper end of the stem shaft 40 to open and close the annular passage 42 on the top surface of the pressure pin 34 . Along with this, the annular passage 42 is opened and closed. The poppet valve 44 is flush with the top surface of the pressure pin 34 when the valve is closed, and is pushed out by the stem shaft 40 to separate from the V-shaped valve seat 46 and protrude from the top surface of the pressure pin 34 when the valve is opened. , the annular passage 42 is open to the top surface of the pressure pin 34 . A sub-actuator (hydraulic cylinder) 48 provided inside the pressure pin 34 is connected to the lower portion of the stem shaft 40 . Therefore, the poppet valve 44 is opened and closed through the stem shaft 40 by moving the secondary actuator 48 up and down within the pressure pin 34 .

An oxygen/hydraulic system as shown in FIG. 3 is used to cause these pressurizing pins 34 to perform a series of operations. First, the annular passage 42 provided in the pressurizing pin 34 is connected to the oxygen supply port 50 so that oxygen can be supplied to the cavity 16 through the pressurizing pin 34 when the valve is opened from the cylinder 52 which is the oxygen supply source. In the middle of the path from the cylinder 52 to the oxygen supply port 50, there are a flow path 58 provided with a large flow rate adjustment valve 54 and an opening/closing valve 56, and a flow path 64 provided with a small flow rate adjustment valve 60 and an opening/closing valve 62. are provided in parallel so that the amount of oxygen supplied can be adjusted.

Next, the configuration for performing secondary pressurization by the pressurizing pin 34 and the configuration for opening and closing the poppet valve 44 attached to the pressurizing pin 34 are as follows. Hydraulic pressure is generated from a hydraulic tank 66 using a pump 68 , and the pump 68 is connected to the main actuator 32 via a direction switching valve 70 so as to vertically drive the pressure pin 34 . The hydraulic pressure of the pump 68 is also used for opening and closing valves, and is introduced to the sub-actuator 48 by a direction switching valve 72 so that the hydraulic pressure can be switched up and down. This allows the pressurizing pin 34 to be moved upward by the primary actuator 32 before the poppet valve 44 is opened by the secondary actuator 48 to introduce oxygen into the cavity 16 . In addition, the sub-actuator 48 is driven downward to close the poppet valve 44 to stop the supply of oxygen, and only the pressurizing pin 34 is raised, so that the second pressurizing means 30 can push the pressurizing pin 34 into the molten metal. It has become.

The hydraulic pressure discharge path 74 when the pressure pin 34 rises is designed to measure the piston drive amount of the main actuator 32 and the stroke of the pressure pin 34 from the amount of discharged oil. The stroke detection device 76 is composed of a cylinder-piston structure, which is composed of a cylinder body 78 and a piston 80 that can slide inside. One chamber partitioned by the piston 80 of the cylinder body 78 is connected to the hydraulic fluid outlet of the pressure cylinder 34 , and the other chamber is connected to the direction switching valve 70 . As a result, the hydraulic oil discharged from the main actuator 32 enters the stroke detection device 76 by the amount discharged, and the piston 80 is moved. A rod 82 is integrally provided with the piston 80 and projects from one end of the cylinder body 78 and is connected to a linear potentiometer 84 . The operation start point of the rod 82 is one end of the cylinder body 78 (the left end in FIG. 3), which coincides with the pressure start point of the piston of the pressure pin 34 (the lower end in FIG. 3). A linear potentiometer 84 is arranged parallel to the rod 82 and moves with the rod 82 to determine its travel distance. In such a stroke detection device 76, the piston 80 is provided with a through-hole communicating with the chambers partitioned by the piston 80, and a check valve 86 and an orifice (throttle valve) 88 are attached to the through-hole. ing. This check valve 86 is a one-way valve that blocks the flow of hydraulic fluid pushed out from the room containing the hydraulic fluid of the pressurizing pin 34 to the chamber on the side of the directional switching valve 70 and allows the flow in the opposite direction. be. As a result, the stroke detection device 76 detects the total amount of hydraulic oil when the pressure pin 34 pressurizes. An orifice (throttle valve) 88 regulates the flow rate of the check valve 86 . Also, if the cracking pressure (spring force) of the check valve 86 is weak, the piston will flow through the check valve in a stopped state.
Incidentally, a control means for controlling the operation system as described above is separately provided, and is controlled so as to operate appropriately.

FIG. 4 shows a manufacturing process using the die casting manufacturing apparatus 10 configured as described above. An orifice 36 is provided in the runner pressurizing path of the pressurizing pin 34 of the second pressurizing means 30 to prevent backflow of gas and molten metal. First, the mold is clamped. When clamping the mold, the plunger 20 is advanced to block oxygen from coming out of the sprue (Fig. 4 (1)). At this time, the pressure pin 34 is in the standby position, that is, in the retracted state from the rising runner portion 28 .

After clamping the mold and before injection by the first pressurizing means 22, the pressurizing pin 34 of the second pressurizing means 30 is moved toward the runner side (FIG. 4(2)) and passed through the orifice 36. , the poppet valve 44 is opened to prevent backflow of gas at the orifice 36, and oxygen is supplied to the cavity 16 from the open annular passage 42 provided in the pressurizing pin 34 (FIG. 4(3)). Gas remaining in the cavity 16 is pushed out by the oxygen and exhausted through the air vent.
After being filled with oxygen, the poppet valve 44 is opened to release oxygen while returning the pressurizing pin 34 to the standby position ((4) in FIG. 4), and the poppet valve 44 is closed at the standby position ((4)). Fig. 4 (5)). At this time, the plunger 20 returns to the injection position, but the internal gas is forced out of the spout by the oxygen.

After the pressurizing pin 34 is returned to the standby position, casting is performed by injecting molten metal from the plunger 20 by the first pressurizing means 22 (FIG. 4(6)). After the plunger 20 reaches the forward limit, the second pressurizing means 30 pressurizes the runner while preventing backflow of molten metal at the orifice 36 (FIG. 4(7)). At this time, the casting pressure by the cavity 16 can be four times as high as in the conventional case.

As described above, in this embodiment, the mold is first clamped, the plunger 20 is advanced and passed through the orifice 36, and the poppet valve 44 provided on the top surface of the pressure pin 34 is opened to blow out oxygen. As a result, the residual gas inside can be pushed out to the air vent, and the cavity can be filled with oxygen at a high concentration. After that, the reaction with the molten metal injected into the cavity 16 can be sufficiently carried out.

In addition, the runner portion can be pressurized by using the backflow prevention effect of the orifice 36, which is four times as much as the conventional pressurization force, which is very beneficial. That is, in the second pressurizing means 30 configured in this manner, when the pressurizing pin 34 reaches the annular projection 38 after the injection by the plunger 20 of the first pressurizing means 22 is completed, the orifice 36 portion is pushed. A metal seal is formed when the upper molten metal is inserted, and the shielding function is exhibited at that part. Therefore, the metal seal at the orifice 36 portion increases the amount of molten metal filled into the cavity 16, and the pushing operation by the pressure pin 34 lengthens the stroke to complete the work. As a result, the product produced by the normal casting method without runner pressurization was "0", and the conventional local pressurization method pressurizing the central part of the cavity 16 increased +4 g (0. 5%), and with the runner pressurization method of this embodiment, an increase of +14 g was observed (1.7%), and the effect of this embodiment was remarkable.

Next, another method for realizing the oxygen supply method for performing the PF method will be described with reference to FIG. FIG. 5(1) shows the mold open state in which the pressurizing pin 34 is retracted from the rising runner portion 28 and is in a standby state. The left and right movable molds 12 and fixed molds 14 are separated from each other, and the two-dot chain line in the center indicates the die cast product, the runner and the biscuit. When the mold clamping operation starts from such a state, as shown in FIG. 5(2), hydraulic pressure is supplied to the sub-actuator 48 of the second pressurizing means 30 during the release agent spraying operation after the product is taken out. , the pressure pin 34 is advanced to the advance limit. As shown in FIG. 3(3), mold clamping proceeds at the same time, and the poppet valve 44 is opened during this mold clamping to discharge oxygen. This oxygen enters the cavity 16 and the residual gas flows through the upper air vent to the atmosphere. Then, the machining operation is started while discharging oxygen, and as shown in FIG. Tighten the valve 44 to prevent air from entering the sleeve 18. It includes oxygen supply for carrying out such PF process.

The annular protrusion 38 forming the orifice 36 may have a square cross section as in the embodiment, but may have a V-shaped or arc-shaped cross section. In this case, if the cutting edge of the V-shape or arc-shaped cutting edge is sharp, the metal seal cannot be obtained, so it is desirable to cut the tip.

Cooling means may also be arranged in the annular projection 38 forming the orifice 36 . This can be done by a horizontal system, a water cooling system, or an oil cooling system, and it is preferable to cool the annular projection 38 when the injection by the first pressurizing means 22 is completed and the pressurization by the second pressurizing means 30 is applied to the annular projection 38 . This facilitates the formation of a metal seal.

In the embodiment described above, the annular projection 38 forming the orifice 36 may be formed as a separate part, and attached by a fitting structure when the runner 24 is formed. This is because the runner 24 has a structure in which the runner 24 splits at the parting line of the mold, so that it can be easily attached to the rising runner portion 28 having a semicircular structure.
The above embodiment can also be applied to pushing runners in hot chambers and molding plastics.

Next, the second embodiment of the present invention will be described in the above embodiment. FIG. 6 shows an example in which the second pressurizing means 30 is arranged on the branch runner. Among these branched runners 90a to 90d, this branched runner 90a is intended because there is a problem that cavities are likely to occur when the molten metal injected from the branched runner 90a on the left side shown in FIG. 6 solidifies in the product. After the runners connected to the selected product portion are selected and the necessary amount of molten metal for the die cast product 92 is injected by the first pressurizing means 22, the second pressurizing means 30 provided on the selected branch runner 90a presses 1 The secondary pressurization is performed at an ultra-high pressure approximately four times as high as the secondary pressurization. Of course, in this case as well, the poppet valve 44 attached to the pressurizing pin 34 is used to replace the internal gas with oxygen in advance before casting. In this case, the direction of movement of the pressing pin 34 is a direction intersecting with the direction of plunger operation of the first pressing means.

Also, FIG. 7 shows a third embodiment. As shown in FIG. 6, the pressure pin 34 may be oriented parallel to the plunger operating direction of the first pressure means 22 . Therefore, the rising runner portion 28 is bent.
Furthermore, by supplying oxygen to the cavity and performing the second pressurization with a new branched runner connected to the part where the density improvement is desired, the production of die casting products that suppresses entrainment cavities and shrinkage cavities due to the PF method and runner pressurization. It can be performed.

FIG. 8 shows a device according to a fourth embodiment. The runner to be subjected to the second pressurization is the degassing runner 94 of the cavity 16 (alternatively a die-cast product) by the first pressurizing means 22, and the degassing runner 94 is formed on the surface corresponding to the runner directly connected to the cavity 16. An orifice 36 is provided through which a pressure pin 34 of the second pressure means 30 is inserted. An annular passage (oxygen supply passage) 42 formed inside the pressurizing pin 34 as a hollow tube structure, and a poppet valve 44 provided at the tip of the pressurizing pin 34 for opening and closing the annular passage (oxygen supply passage). be provided. When clamping the mold, the pressurizing pin 34 of the second pressurizing means 30 is operated before injection by the first pressurizing means 22, and the orifice 36 is provided on the pressurizing pin 34 while preventing gas backflow. Oxygen is supplied to cavity 16 by poppet valve 44 . This oxygen fills the cavity 16, and the previously filled gas is discharged through the air vent and through the branch runners 96a-96d from the molten metal filling opening in the sleeve. Thereafter, the pressurizing pin 34 is returned to the standby position, and after the molten metal is filled in the first pressurizing means 22 and pressurization is completed, the second pressurizing means 30 is operated again to pressurize the cavity 16 from the degassing runner 94 . . Control means (not shown) is provided to control this series of operations. Also in this embodiment, the PF method by supplying oxygen to the cavity 16 and secondary pressurization by the second pressurizing means 30 are realized, and a die cast product with improved entrainment cavities and shrinkage cavities can be obtained.

FIG. 9 shows a fifth embodiment. This is applied particularly to the case where secondary pressurization is performed partially in the fourth embodiment. is used to provide the second pressurizing means 30 . By providing an orifice 36 and inserting a pressure pin 34 through the orifice 36, the same effect as in the above embodiment can be exhibited.

In the present invention, the poppet valve 44 described above is set so as to be flush with the top surface of the pressurizing pin 34 . If this poppet valve 44 has the same diameter as the pressure pin 34 and has a flange, a runner pressurizing stroke is required for the height H of the flange. Oxygen gas can be supplied in the shortest stroke. Also, if there is a flange when it is removed after being cast and pressurized by the runner, it is expected that the poppet valve 44 will not come off because it will be wrapped in aluminum by the height H, but after modification, that possibility will disappear. . Furthermore, when a flanged valve is provided at the upper end of the pressurizing pin 34, when the pressurizing pin 34 is actuated, the tip valve is rubbed because there is not much difference in diameter from the orifice 36 when the pressurizing pin 34 is actuated. Since the valve 44 is formed with a smaller diameter than the end face, such a problem can be prevented.

In the present invention, the runner can be pressurized by the second pressurizing means following the plunger pressurization of the first pressurizing means in die casting, and the product can be produced by the PF method by oxygen supply in the former stage and the runner pressurization in the latter stage. To provide a method and apparatus capable of manufacturing products without causing dents and improving product density.

DESCRIPTION OF SYMBOLS 10... Die-cast manufacturing apparatus, 12... Movable mold, 14... Fixed mold, 16... Cavity, 18... Injection sleeve, 20... Plunger, 22... First pressurizing means, 24... Runner 26... Diverter runner part 28... Rising runner part 30... Second pressurizing means 32... Main actuator 34... Pressurizing pin 36... Orifice 38... Annular projection, 40...stem shaft, 42...annular passage, 44...poppet valve, 46...valve seat, 48...sub-actuator (hydraulic cylinder)...for poppet, 50...oxygen supply port, 52...cylinder ( Oxygen supply source), 54 Large flow rate adjustment valve 56 Open/close valve 58 Flow path 60 Small flow rate adjustment valve 62 Open/close valve 64 Flow path 66 Hydraulic tank , 68...pump, 70...direction switching valve, 72...direction switching valve, 74...hydraulic pressure discharge path, 76...stroke detector, 78...cylinder body, 80...piston, 82...rod, 84...Potentiometer, 86...Check valve, 88...Orifice, 90a~90d...Branch runner, 92...Die-cast product, 94...Gas release runner, 94a~94c...Branch gas release runner, 96a~ 96c……Diverting runner.

Claims (22)

A method of injecting molten metal from a sleeve by a first pressurizing means and then pressurizing a runner by a second pressurizing means,
Oxygen can be supplied through the tip valve from an oxygen supply channel provided inside the pressurizing pin by using the pressurizing pin of the second pressurizing means,
After the pressurizing pin of the second pressurizing means is protruded into the runner in advance, the inside of the cavity is filled with oxygen through the tip valve and drawn in, and then injected through the sleeve by the first pressurizing means. and then runner pressurization by said second pressurizing means. 2. A die casting manufacturing method according to claim 1, wherein an orifice is provided in the runner pressurizing path of the pressurizing pin of said second pressurizing means to prevent backflow of gas and molten metal. In the method of injecting the molten metal from the sleeve by the first pressurizing means after mold clamping and pressurizing the runner portion directly connected to the cavity by the second pressurizing means,
An orifice is provided in the runner pressurizing path of the pressurizing pin of the second pressurizing means to prevent backflow of gas and molten metal,
The pressure pin of the second pressure means is actuated to the runner advance limit from the start of mold clamping to the injection by the first pressure means, and an oxygen supply valve provided on the pressure pin while preventing gas backflow at the orifice. Oxygen is supplied back to the cavity by
After the molten metal is injected by the first pressurizing means, the runner pressurization is performed by the second pressurizing means while preventing the backflow of the molten metal at the orifice.
A die casting manufacturing method characterized by: In the method of injecting the molten metal from the sleeve by the first pressurizing means after mold clamping and pressurizing the runner portion directly connected to the cavity by the second pressurizing means,
At the same time as the mold clamping start operation, oxygen supply operation to the cavity from the oxygen supply valve provided on the pressurizing pin of the second pressurizing means while preventing gas backflow by the orifice;
molten metal injection operation by the first pressurizing means via the sleeve;
a runner pressurizing operation by a second pressurizing means using a pressurizing pin while preventing backflow of the molten metal by the orifice;
A die casting manufacturing method characterized by performing a step of 5. Any one of claims 1, 3 and 4, wherein the pressurizing pin of said second pressurizing means is provided with a poppet-type valve at its tip, and the opening and closing operation of this valve opens and closes the oxygen supply passage formed in the central portion. 2. A die casting manufacturing method according to claim 1. 6. The die casting manufacturing method according to claim 5, wherein the poppet type valve has a diameter smaller than the outer diameter of the pressure pin and is opened and closed by the top surface of the pressure pin. 5. A die casting manufacturing method according to claim 1, wherein said orifice is formed on a surface of said runner corresponding to a runner portion directly connected to said cavity to prevent backflow of gas or molten metal. Injection into the cavity is via a plurality of branched runners, and the orifice is formed on a surface corresponding to the rising runner portions of selected branched runners or the vicinity thereof to prevent backflow of gas or molten metal. 5. A die casting manufacturing method according to any one of claims 1, 3 or 4, characterized in that it is prevented. 5. The die casting according to claim 1, wherein the moving direction of the pressing pin of said second pressing means is a direction intersecting with the plunger operating direction of said first pressing means. Production method. 5. The die casting according to claim 1, wherein the moving direction of the pressing pin of said second pressing means is parallel to the plunger operating direction of said first pressing means. Production method. 5. The die casting manufacturing method according to claim 1, wherein the second pressure is applied to the cavity by means of a new branch runner connected to the portion where the density improvement is desired. After the molten metal is injected into the clamped mold by the first pressurizing means, when performing the second pressurization through the runner directly connected to the cavity by the second pressurizing means,
The runner is a runner for degassing the cavity by the first pressurizing means,
After the start of mold clamping and before injection by the first pressurizing means, the pressurizing pin of the second pressurizing means is actuated to prevent backflow of gas at the orifice, and the oxygen supply valve provided on the pressurizing pin allows the gas to flow into the cavity. supply and return oxygen,
A die casting manufacturing method, wherein the second pressurizing means is operated to pressurize the cavity from the degassing runner after the pressurization by the first pressurizing means is completed. a first pressurizing means for injecting molten metal into the die casting mold;
a second pressurizing means for pressurizing the runner communicating with the cavity;
an oxygen supply path in which the pressurizing pin of the second pressurizing means is formed as a hollow tube structure;
a valve provided at the tip of the pressurizing pin that opens and closes the oxygen supply channel;
A die casting manufacturing device consisting of: 14. A die-cast manufacturing apparatus according to claim 13, wherein an orifice formed in a surface corresponding to a runner directly connected to said cavity and through which a pressure pin is inserted is provided. a first pressurizing means for injecting molten metal into the die casting mold;
a second pressurizing means for pressurizing the runner communicating with the cavity;
an orifice formed on a surface corresponding to the runner directly connected to the cavity and through which the pressure pin of the second pressure means is inserted;
an oxygen supply channel formed inside the pressurizing pin having a hollow tubular structure; and a valve provided at the tip of the pressurizing pin for opening and closing the oxygen supply channel;
A die casting manufacturing apparatus characterized by providing a. 16. A die casting manufacturing method according to claim 13 or 15, characterized in that said orifice is formed in the vicinity of a boundary portion between a diverter runner portion for guiding molten metal injection from the second pressurizing means to the cavity and a rising runner portion. Device. Said runner comprises a plurality of branched runners, and orifices are formed on the surface corresponding to the selected branched runners, and the valved pressure pin of the second pressure means can be inserted into said orifices. 16. A die casting manufacturing apparatus according to Item 13 or 15. 16. A die casting manufacturing apparatus according to claim 13 or 15, wherein the moving direction of the pressure pin with a valve of the second pressure means is a direction intersecting with the direction of the plunger of the first pressure means. 16. A die casting manufacturing apparatus according to claim 13 or 15, wherein the moving direction of the pressure pin with valve of said second pressure means is parallel to the direction of the plunger of said first pressure means. The first pressurizing means is provided with a new branch runner connected to the portion where the density is to be improved, and the second pressurizing means having a pressurizing pin with a valve that moves in the same direction as the flow of the molten metal in the new branch runner. 16. A die casting manufacturing apparatus according to claim 13 or 15, characterized in that it is provided. a first pressurizing means for injecting molten metal into the die casting mold;
a second pressurizing means for pressurizing the runner communicating with the cavity;
The runner is an auxiliary runner provided at a portion where the molten metal filled in the cavity by the first pressurizing means overflows,
an orifice formed in the auxiliary runner on a surface corresponding to the runner directly connected to the cavity and through which the pressurizing pin of the second pressurizing means is inserted;
an oxygen supply channel formed inside the pressurizing pin having a hollow tubular structure; and a valve provided at the tip of the pressurizing pin for opening and closing the oxygen supply channel;
After the start of mold clamping and before injection by the first pressurizing means, the pressurizing pin of the second pressurizing means is actuated to prevent backflow of gas at the orifice, and the oxygen supply valve provided on the pressurizing pin allows the gas to flow into the cavity. a control means for controlling a series of operations for supplying and returning oxygen, and after pressurization by the first pressurizing means is completed, the second pressurizing means is operated to pressurize the cavity from the auxiliary runner;
A die casting manufacturing apparatus characterized by comprising: A pressurizing means for pressurizing a runner of a die casting mold, comprising a main actuator, a pressurizing pin moved in and out by the main actuator, an annular passage provided inside the pressurizing pin, and opening and closing the annular passage. A pressurizing device comprising a poppet valve attached to the top surface of a pressure pin and having a smaller diameter than the top surface, a stem shaft that operates the poppet valve and forms the annular passage, and a sub-actuator that drives the stem shaft. means.

Images