JPS62161449A - Casting method for vertical casting type die casting machine - Google Patents

Abstract

PURPOSE:To prevent generation of blow holes or pin holes in casting products by executing a casting under vacuum sucking from air intrusion part situated lower part than molten metal upper surface of a cavity at the specified time before starting vacuum sucking in the cavity. CONSTITUTION:By generating a negative pressure in a suction hole of a plunger rod at opening a solenoid valve 116, air in an annular groove 59c of the plunger chip 59a is sucked up through an air passage 80. And by generating a negative pressure in an air passage 30b at opening a solenoid valve 120 at the same time of opening the solenoid valve 116, air in annular grooves 30a, 32a are sucked up through the air passage 30b. Further, by opening a solenoid valve 117 after about 0.1sec later than the opening time for the above-mentioned valves, gas in the cavity 35 is exhausted by sucking up from an exhausting hole. As a vacuum degree in the plunger 59 side is higher than a vacuum degree in the gas sucking apparatus side by sucking up air in the plunger 59 side at slight early time, the air intrusion from gap between an injection sleeve and the plunger chip 59a is shut out.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is a vertical casting type die casting machine, in which an injection sleeve, which is a movable sleeve, is inserted into an injection hole of a mold, and the molten metal in the injection sleeve is poured into a mold. This relates to a casting method that involves injection into the cavity of a mold.

[Prior art] Casting using a die-casting machine has been widely used as a method for manufacturing precision products using a large amount of liquid.This type of casting involves casting molten metal into a mold cavity at high speed and under high pressure. The gas in the cavity may not be sufficiently removed during filling, and may mix with molten metal and remain in the product as cavities, so it may not be suitable for products where integrity without cavities is important. there were.

In order to eliminate such inconveniences, the present applicant proposed a method for removing gas from the mold cavity during casting using Utility Model Publication No. H-19807 etc., which eliminates gas entrainment and provides a sound die-cast product. We developed and proposed a degassing device.

This device is equipped with a gas vent valve in the gas exhaust path leading from the mold cavity to the outside of the mold, and when the valve is open, the molten metal is injected into the cavity, allowing the small mass of gas in the cavity to be exhausted. When the gas has finished being discharged through the gas passage, the inertial force of the large mass of the molten metal that has entered the gas exhaust passage from inside the cavity is applied to the front valve to close it, thereby blocking the outflow of the molten metal. This allows gas to be removed from the mold reliably and easily.

The applicant has also developed a reduced-pressure or vacuum-type die-casting method and its apparatus, in which the gas in the mold cavity is inoculatedly discharged by connecting the gas discharge path to a vacuum generator. This reduced pressure die-casting method reduces the pressure by suctioning an amount of gas from the outside that is greater than the amount of gas that flows into the cavity from outside the mold through the gap, thereby ensuring more reliable degassing within the mold. It can be done.

[Problems to be solved by the invention] However, in such a conventional injection device,
If the inside of the mold cavity is evacuated only from above, injection may cause damage to the joint between the fixed sleeve and the injection sleeve at the bottom of the mold, between the injection sleeve and the plunger tip,
Since outside air is sucked in from the mating surface, which is the t-split part of the fixed sleeve at the bottom of the mold, the plunger is closed at the start of injection.

When the solidified layer that forms at the tip of the sleeve breaks during injection, air entering from the joints of the injection sleeve enters the molten metal and enters the mold cavity together with the molten metal. Namely.

As shown in FIG. 12, which is a cross-sectional view of the injection sleeve insertion part,
A half-shaped fixed sleeve 5, 5a is fitted into the injection hole 4 of the mold 3.3a having a cavity 1 and a constriction 2, and an injection hole into which molten metal 6 is supplied for injection. Sleeve 7 is loaded and injection sleeve 7
A plunger tip 8 is slidably inserted into the inner hole. Then, at the start of injection, the plunger tip 8
A solidified layer 9 is generated by the solidification of the molten metal 6 on the molten metal contacting end surface and the inner surface of the injection sleeve 7 which is continuous therewith. The fixing sleeve 5.5a is compressed and crushed between the front plane lO and the end face of the plunger tip 8, without entering the gap l.
It remains inside together with the biscuit which is the solidified product of the molten metal 6.
When the product is taken out, it is separated from the constriction 2 together with the biscuit.

However, in the conventional injection device described above, when the gas in the cavity 1 is vacuum-suctioned, the injection hole 4 of the mold 3
Air is sucked from the gap between the injection sleeve 7 and the injection sleeve 7 inserted therein, the sliding surface between the injection sleeve 7 and the plunger tip 8, the mating surface of the fixed sleeve 4.5, etc. as shown by the arrow in the figure. , this air enters between the inner surface of the fixed sleeves 5, 5a and the coagulated layer 9, while the coagulated layer 9 is compressed by the plunger tip 8 and hits the plane lO, so that the coagulated layer 9 is solidified as shown by reference numeral 9A in the figure. When M9 breaks one after another,
The air that has entered enters the molten metal between the broken solidified layer pieces 9A, passes through the molten metal, and enters the cavity 1 from the constriction 2. The fact that the air and the molten metal alternately pass through the constricted portion 2 has the disadvantage that the flow of the molten metal is more disturbed, making it impossible to obtain a high-quality cast product.

[Means for Solving the Problems] In order to solve these problems, in the present invention, from the air intrusion portion located below the upper surface of the molten metal in the cavity, at least 0.1 seconds after the start of vacuum suction into the cavity. A method was adopted in which molten metal was poured using vacuum suction beforehand.

[Function] With the above-mentioned structure, during casting, immediately before starting the vacuum suction in the cavity, the air inlet part below the top surface of the molten metal can be vacuum-suctioned, and the air in the joints of the mold and the cast parts can be vacuum-sucked. This prevents air from being drawn in from areas where air can easily enter.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

First, the overall structure of the horizontal clamping vertical casting injection molding apparatus will be explained with reference to FIGS. 2 and 3.

In Fig. 2.3, the die casting machine 21 is equipped with a horizontal mold clamping unit 22 and a vertical casting unit 23, and the entire horizontal mold clamping unit 22 is fixed on a machine base 24 fixed to a floor surface. This machine base 24
are a pair of left and right support members 24a extending in the length direction of the machine base.
and a connecting member 24b (the one at one end is not shown) that connects both ends thereof, and the upper ends of the left and right supporting members 24a are formed with a flat rectangular cross section. A pair of left and right slide plates 24c as long slide members are integrally formed in parallel with each other. The fixed platen 25 of the horizontal mold clamping unit 22 is integrally made up of a substantially square vertical member 25a having sufficient rigidity and a horizontal member 25b extending horizontally from the lower end of the vertical member 25a excluding the parts on the left and right slide plates 24c. The lower end of the vertical member 25a is fixed to the machine base 24 by fixing it to the slide plate 24c with a plurality of bolts. And fixed! The horizontal member 25b of 125 has a width indicated by the symbol W in FIG. 3 that is slightly smaller than the interval between the slide plates 24c indicated by the symbol 2 W1, and is not fixed to the machine base 24. It is configured to bend downward, albeit slightly, when an external force is applied.

A cylinder platen (not shown) is fixed to the other end of the machine base 24 so as to be freely movable and adjustable, facing the fixed platen a25.
The four spaces are connected by a column 27 fixed at 6. 28 is a movable plate on which a column 27 is fitted facing the fixed plate 25, and the fixed plate 2 is mounted on the sliding plate 24c.
5, and is connected to a cylinder platen (not shown) by a toggle mechanism 29. Reference numeral 30 denotes a key 3 whose movement in the vertical direction is regulated by a key 31 provided horizontally in the fixed @ 25 and provided vertically in the center of the fixed plate 25.
1a is a fixed mold that is positioned perpendicular to the paper surface, and 32 is a movable mold that is mounted on the movable platen 28 with its movement in the vertical direction restricted by a key 33. The molds 30 and 32 are joined horizontally with a mating surface 34 as a boundary so as to be openable and closable. Here, the reason why the vertical key 31a is provided between the fixed platen 25 and the fixed mold 30 on the center line of the machine is that the key 31a is provided on the mating surface of the fixed mold 30 and the movable mold 32 on the center line of the machine. This is to easily align the horizontal center of the fixed mold 30 with a casting sleeve 58 (described later) of the vertical casting unit 23 provided below the mold 34.

39 is a product extrusion device that extrudes the cast product from inside the cavity 35.

As shown in FIG. 2, the mating surfaces 34 of the fixed mold 30 and the movable mold 32 are located at different positions in the cavity 35 and the fixed sleeve 38 mounting portion, which is the lower end of the mold. That is, in the example shown in FIG. 2, the mating surface 34 at the lower end of the mold is close to the fixed platen 25, and the mating surfaces 34 at other parts including the cavity 35 are located far from the fixed platen 25. The mating surface 34 is hooked. and,
At the lower ends of the mating surfaces 34 of the molds 30 and 32, a vertical hole 37 that opens downward from the bottom and this vertical hole 37 are formed.
A halved cylindrical fixed sleeve 38 is fitted into the vertical hole 37, and a runner 36 for pouring molten metal, which is also a constriction, is provided toward the top of the vertical hole 37.
A vertical gate 36a communicating from the upper end of the cavity 35 to the lower part of the cavity 35 is provided. Therefore, the horizontal position of the gate 36a is offset from the vertical central axis of the fixed sleeve 38.

The fixed sleeve 38 is provided with a ring-shaped groove 38a on the inner peripheral surface near the top. In addition, the lunch 36 set diagonally
A concave portion 36b is provided at the upper end of the runner 36a, which is continuous with the vertical gate 36a, on the side where the runner 36 faces diagonally. These grooves 38a and recesses 36b are both formed by the injection sleeve 5, which is a fixed sleeve or a movable sleeve to be described later.
This is provided to capture shells that are solidified molten metal produced on the inner circumferential surface of the cavity 35 to prevent the shells from entering the cavity 35. When providing the groove 38a on the inner peripheral surface of the fixed sleeve 38, the distance from the top of the fixed sleeve 38 to the upper surface of the groove hIt38a is
It is preferable to set the ratio of 0.15 times the diameter of the inner circumferential surface of No. 8 to about 5:1 to 0.5:1 from the viewpoint of capturing the coagulated layer.

On the other hand, the vertical casting unit 23 is connected to the horizontal member 2 of the fixed platen 25.
It is equipped with four tie rods 40 whose upper ends are screwed into screw holes provided in 5b and hang down.

This tie rod 40 is attached to both support members 2 of the machine base 24.
4a, and is inserted into a bit 41 provided below the floor surface. 42 is a pair of supporting members 42a and a connecting member 42b connecting both ends thereof.

42c and integrally formed into a rectangular frame shape, two tie rods 40 are inserted into each support member 42a by threaded portions at their lower ends.
By screwing together and tightening a pair of upper and lower nuts 43 and 44, the frame 42 is firmly supported in a horizontal state.

The injection device 45 is supported by the frame 42 so as to be freely tiltable. That is, the injection device 45 includes a clevis-shaped injection cylinder 55 that is swingably supported by the frame 42 . That is, injection cylinder 5
A tilting shaft is provided on both sides of the rod side block 46 of No. 5, and by supporting this tilting shaft with a shaft hole of the frame 42, the entire injection device 45 is supported by the frame 42 so as to be freely tiltable. has been done. Reference numeral 52 denotes a pair of docking grams that stand upright on both sides of the rod-side block 46, and have a main portion shaped like a round bar.A cylinder hole of the sleeve frame 53 is slidably fitted into the dotting grams 52. There is.

The sleeve frame 53 has a coupling receiving portion 5 at the lower end.
3b, a cylinder portion 53c extending upward from both sides thereof, and a sleeve support portion 53d that connects the cylinder portions 53c on both sides at the upper end. It is configured to rise from a position of In Figure 3, 54a is fixed @
25 is a stopper that restricts the upper limit of the sleeve frame 53, and 54b is a stopper that is fixed to the frame 42 and restricts the lower limit of the sleeve frame 53.

The injection cylinder 55 is provided with a piston rod that moves up and down by introducing pressure oil into the cylinder tube 50, and this piston rod passes through a rod hole in the frame 46. Reference numeral 58 denotes an injection sleeve, also called a movable sleeve, which is formed into a cylindrical shape and is fixedly supported by the sleeve support portion 53d at the upper end of the sleeve frame 53. Inside the injection sleeve 58, a plunger tip, which is the tip of the plunger 59, moves up and down. The lower end of the plunger 59 is concentrically connected to the piston rod 56 of the injection cylinder 55 by a coupling 60. The outer circumferential surface of the lower end of the coupling 60 can come into contact with or rub against the inside of the upper surface of the coupling receiving portion of the sleeve frame 53. As the sleeve frame 53 rises, the injection sleeve 58 fits into the reassembly hole 37 shown in FIG. Both of the injection sleeves 58, which are ribs configured to rise along the inner bore of the fixed sleeve 38, are collectively referred to as a casting sleeve, and 62 is a fixed sleeve.
This centering ring is fixed to the horizontal member 25b of No. 25 and guides the injection sleeve 58.

Next, a tilting device for tilting the entire injection device 45 for pouring will be described. The rod side block 46 of the injection cylinder 55 and the head cover are connected to a pair of connecting plates 63.
A pair of brackets 64 are fixed to the connecting member 42b of the frame 42 and project diagonally downward. Reference numeral 65 denotes a tilting cylinder rotatably supported by a bracket 64 via a bearing 66, the working end of the piston rod 67 is pivotally connected to the connecting plate 63 by a pin 68, and the piston rod is rotated by pressure oil. By moving 67 forward and backward, the entire injection device 45 is configured to stand upright or tilt between the solid line position and the chain line position in FIG. In addition, the injection device 45
A striker 69 is fixed at the shaft end of the tilting shaft which rotates in unison with the shaft 41 and the frame 42ζ1.
A pair of upper and lower limit switches 70 and 71 corresponding to the working end of the striker 69 are predetermined, and the structure is such that the rising and #T4 rolling operations of the injection device 45 are stopped when these limit switches come into contact.

Next, details of the vacuum suction mechanism and vacuum suction system will be explained with reference to FIG. 1 and FIGS. 4 to 11.

In each figure, the same or corresponding parts as in FIGS. 2 and 3 are denoted by the same reference numerals, and the explanation thereof will be omitted.

In the ta, etc., the fixed mold 30 and the movable mold 32 are 1
They are joined at a mating surface 34 and the mold is clamped, and inside thereof, a cavity 35, a constriction 36, and an injection hole (vertical hole) 37 are formed on both sides of the mating surface 34. The die casting machine of this embodiment is of a horizontal mold clamping type and a vertical casting type, in which a pair of half-shaped fixed sleeves 38 and 38 are respectively fitted.
Mold clamping and mold opening are performed by moving the mold in the horizontal direction, and the injection cylinder 55 is disposed directly below the mold 30° 32. The injection cylinder 55 is equipped with a piston rod 55at- which moves forward and backward by hydraulic pressure, and a fourth piston rod 55at- is provided at the working end.
Plungers 59, details of which are shown in FIGS. 7 to 7, are concentrically connected by a coupling 60. Reference numeral 58 denotes an injection sleeve which is formed to have the same diameter as the fixed sleeve 38 and is inserted into and removed from the fixed sleeve 38, and whose inner hole 5
8a includes a plunger tip 5 at the head of the plunger 59.
9a is slidably inserted into the injection cylinder 55, and the injection sleeve 58 is removed from the fixed sleeve 38, and the plunger tip 59a is inserted into the injection cylinder 55 and the tilting cylinder 65.
The molten metal is injected into the injection sleeve 58 by tilting the injection sleeve 58. After pouring the molten metal, the injection cylinder 55 is raised, the injection sleeve 58 is pressed against the fixed sleeve 38, and the piston rod 55a is advanced by hydraulic pressure, so that the plunger tip 59a injects the molten metal into the cavity 35.

Here, details of the plunger 59 will be explained.

As shown in FIG. 4, the plunger rod 72 connected to the piston rod 55a by the coupling 60 has a screw hole 72a and a pressure reducing pipe support hole 72b from above.

The air passage hole 72c is provided with an inner hole formed in a step-like manner in the order of a bottom hole (not shown), and the topmost screw hole 72a has a screw hole 72a.
The lower threaded portion 73a of the threaded pipe 73 is screwed all the way in until it stops at the stepped portion. Central unthreaded part 7 of threaded pipe 73
A pair of upper and lower adapters 74 and 75 are loosely attached to 3b, and are clamped and fixed between the plunger tip 59a screwed into the upper threaded portion 73c of the threaded pipe 73 and the plunger rod 72. Reference numeral 76 denotes a pressure reducing tube consisting of a holding cylinder (not shown) at the end and a pipe 76a welded to the holding cylinder, which is inserted from the bottom hole 72d side and the holding cylinder is inserted into the upper end of the bottom hole (not shown) at the lower end of the plunger rod. The tube 76a passes through the air passage hole 72c and its upper portion is fitted into the pressure reducing tube support hole 72b. A water-cooled tube 77 is held at the lower end of the plunger rod 72 and passes through the holding cylinder, the tube 76a, and the threaded tube 73. ) To Cao Huong Mayu Ok Mountain M
There is a t-shika. Reference numeral 78 indicates O-rings as sealing materials provided at various locations.

An annular groove 59c provided on the outer periphery of the plunger tip 59a
The annular groove 74a provided in the adapter 74 is the air passage 59.
d, and an annular groove 75a provided in the adapter 75 connects to an air passage 75 equipped with a filter 79 made entirely of mesh.
They are connected by b. An air passage 80 formed between the air passage hole 72c of the plunger rod 72 and the pipe 76a communicates with the annular groove 75a through an air passage 81, which is opened at the lower end of the air passage 80. A pipe 83 equipped with a flexible portion 82 of a pneumatic circuit (described later) shown in FIG. On the other hand, the water cooling pipe 77a has a lower end opening connected to a cold water inlet (not shown) at the lower end of the plunger rod 72 via a cold water passage, an annular groove, etc., and an upper end opening connected to the space 59.
The bait is passed through a cold water outlet (not shown) at the lower end of the plunger rod 72 via a cold water passage 84 extending downward around the tube 77a and a water channel. The cold water inlet is connected to a pump or the like by a flexible hose or the like, and the cold water supplied to the cold water inlet by the operation of the pump rises in the pipe 77a and fills the space 59b, and the plunger tip 59
After cooling the water a, it flows down the cold water passage 84 and is drained from the cold water outlet.

Next, the mold degassing device will be explained with reference to FIG. 10.11. Cavity 35 of both molds 30 and 32
As shown in FIG. 11, a gas venting path 85 and a gas venting groove 86 communicating with the outer peripheral portion are formed on both sides of the mating surface 34. .

It is located directly above this gas vent yt86 and is fixed, for example, to the movable mold 32 side. That is, as shown in FIG. 10, a cylinder 89 is attached to the upper end of a bracket 88 fixed to the movable mold 32, and a lower end flange portion, which is the working end of a piston rod 90, which moves back and forth with the fluid pressure of the cylinder 89, In this case, a cylindrical spool 91 has a lower end attached to both sides of the spool 3.
It is fixed by being removably inserted into the circular hole on the upper end surface of 0.32 mm. The cylinder 89 is then used for mold clamping and mold opening.
Due to the operation of the spool 91 via the piston rod 9o
are configured to be inserted into and removed from the molds 30 and 32. Below the spool 91 inserted into the molds 30, 32, there is a valve chamber 92, and a valve chamber 92. A bypass 93 is provided to communicate between the gas vent grooves 86, and a valve seat 94 facing the valve chamber 92 is formed on the lower end surface of the spool 91. Both rod portions 96a of a return rod 96 are slidably engaged with a pair of elongated holes 95 provided in the outer peripheral wall of the spool 91, and there is a gap between the return rod 96 and the flange portion of the piston rod 90. , members such as a tension spring 97 that urges the return rod 96 upward, a cylinder, a gravity fixture of the solenoid device 1, etc. are suspended. Below the return rod 96, a valve guide 98 integrally formed with a cylindrical portion 98a and a pair of screw hole portions 98b is fixed to the spool 91 with the screw hole portion 98b attached inside the elongated hole 95. A valve rod 101 whose upper end threaded portion is screwed into a screw hole of the return rod 96 is slidably supported on the cylindrical portion 98a. A valve body 101a is provided at the lower end of the valve stem 101 and seats on the valve seat 94 when the valve stem 101 rises, and the valve body 101a seats on the valve seat 94 when the valve stem 101 rises.
The valve body 101a, which had been opened due to the gas pressure inside, is seated due to the inertia of the molten metal advancing at high speed from inside the cavity 35, and opens into the interior of the spool 91 and the gas vent groove 86. It is configured to be cut off from the bypass 93. 102 is the groove 1 of the valve stem 101 due to the bias of the compression coil spring 103.
A pole that engages with 01b, a bolt 100, and a nut 101 form an engagement IL mechanism. The valve body 101a, once closed by the pressure of the molten metal, is configured not to open again due to the action of members such as the tension spring 97 unless an external force is applied. The valve body 101a is opened by pushing down the rod portion 96a of the return rod 96, and 104 is a stopper that restricts the upper limit of the rise of the rod portion 96a of the return rod 96, which rises together with the spool 91 by the operation of the cylinder 89. It is fixed to a bracket 88. And S-/++, OI M 'r A'
Beard 69 t=lto IL&II 1 n
Rac+tn r'l -, and this exhaust hole 105 connects to the piping 10 of the pneumatic circuit (described later) shown in FIG.
6.

As shown in FIG. 4, the injection sleeve 58 into which plunger tips 59a of one or more plungers 59 are slidably inserted can be inserted into and removed from the injection hole 37 of the mold 30, 32 as described above. The upper end portion thereof is formed into a tapered shape, and the upper end surface 58b of the fitting portion is pressed against and comes into contact with the injection sleeve contact surface 38a of the lower end surface of the fixed sleeve 38. There is. In addition, this both sides 5
Between 8b and 38a, a sealing material 38b formed in a half ring shape using a heat-resistant material such as copper or asbestos may be fixed to the fixed sleeve 38 side. Further, between the injection sleeve 58 inserted into the injection hole 37 and the injection hole 37, an annular groove 30a, 3
2a is provided in half on the mold 30, 32 side, and an air passage 30b is communicated with the annular groove 30a on the fixed mold 30 side and opened to the outside of the mold. Piping 107 shown in the figure is connected.

Further, as shown in Fig. 8.9, the outer circumferential side of the half-shaped fixed sleeve 38 which is fitted into the injection hole 37 and is integrally attached to the fixed mold 30 of the movable mold 32 at which split surface part. is provided with a vertical groove 32b slightly apart from the dividing surface of the fixed sleeve 38 and parallel to the fixed sleeve 38,
A lower end portion of the vertical groove 32b communicates with the annular groove 32a.

Next, a pneumatic circuit including the plunger 59, the annular groove 32a, and the gas venting device 87 will be explained based on FIG. The pipe 109 connected to the vacuum pump 108 is branched into a pipe 11O and a pipe 111 in the middle, and the pipe 109,
On top of 110 are a vacuum tank 112 and an auxiliary vacuum tank 11.
3 are provided respectively, and piping 109,
110 is connected to the pipe 1 via filters 114 and 115.
06.83 respectively. And piping 1
10. Solenoid valves 116 and 117 are respectively arranged on Ill, and when the solenoid of the solenoid valve 118 is energized from the state shown in the figure, the air in the plunger 59 is sucked,
Furthermore, when the solenoid of the electromagnetic valve 117 is energized, air in the cavity 35 is sucked through the gas venting device 2t87. In this case, the gas venting device'g! The setting is such that the suction on the I87 side is delayed from the suction on the plunger 59 side, for example, by about 0.1 to 1 second, preferably by about 0.3 to 0.5 seconds. Further, the degree of vacuum is set to, for example, 200 to 300 Torr on the lower side of the plunger 59 and the like, and 150 to 250 Torr on the side of the gas venting device 2187, and this is achieved by providing the auxiliary vacuum tank 113.

The auxiliary vacuum tank 113 is provided as close to the plunger 59 as possible, taking into account the resistance that occurs in relatively thin piping sections and passages during vacuum suction, and the piping 83 with the flexible hose 82 is made as short as possible. The diameter of the tube is relatively large, for example, 1 inch.

Furthermore, a pipe 107 including a filter l18, a flexible part 119, and a solenoid valve 120 is connected to the air passage 30b provided in the fixed mold 30, and this pipe 107 is connected to the plunger 59 from the auxiliary vacuum tank 113. It is connected to the front of the electromagnetic valve 116 of the piping 83 going to.

Furthermore, the other boat of the solenoid valves 116, 117, 120 has a piping 124 equipped with solenoid valves 121, 122, 123.
, 125, and 126 are connected to each other, and these pipes 124, 125, and 126 are joined to a pipe 128 equipped with a variable throttle valve 127 and a pressure regulating valve, and connected to, for example, an air compressor 129 in a factory. . And solenoid valve 1
16. Close 117 and 120 and open the solenoid valves 121° and 122.
By opening 123, high-pressure air is sent to the plunger 59, the injection sleeve 58, and the gas venting device 87, and is used for spraying for internal cleaning.

A casting method using the die casting machine configured as above will be explained. The movable mold 32 is moved to the position shown in FIG. 2, the mold is clamped, and the cylinder 89 of the degassing device 87 is
91. as shown in FIG. 1O.
are inserted into the spool holes of the molds 30 and 32. At this time, since the piston rod 55a and the injection sleeve 58 of the injection cylinder 55 are lowered, the injection cylinder 55 is tilted and the plunger 58 is moved downward, as shown by the chain line in FIG.
Inject the molten metal into the injection sleeve 5B where 9 is descending,
After being erected again, as shown in solid lines in FIG. 2, the injection sleeve 58 is raised to engage the locking sleeve 38 as shown in FIG. 1.4.8. After evacuating, which will be described later, oil is supplied to the injection cylinder 55 and the piston rod 55a is raised, the plunger 59 is raised and injection of molten metal indicated by reference numeral 127 in FIG. 4 is started. At this time, cold water is being supplied to the plunger 59 from the cold water inlet 83, and this cold water rises in the pipe 77a, overflows into the space 59b, and flows down in the cold water passage 84, so that the plunger tip 59a and Plunger rod 72 is being cooled. In addition, the injection sleeve 5
8 is also cooled from the outside by a cooling device (not shown). Therefore, on the end of the plunger tip 59a and on the inner wall surface of the injection sleeve 58 that follows it, a solidified layer is formed by the solidification of the molten metal, as indicated by reference numeral 9 in FIG. 4 and FIG. 12. Since the inside of the vacuum tank 112 and the auxiliary tank 113 have been previously depressurized by suction with the vacuum pump lO8, when the solenoid valve 116 is first opened before or during injection, the suction hole of the plunger rod 72 is opened. Negative pressure acts on the plunger tip 5
The air in the annular groove 59c of 9a flows through the air passage 59d, the annular groove 74a, the filter 79, the air passage 75b, and the annular groove 75.
a, the air passage 81, and the air passage 80. Also, at the same time as the solenoid valve 116 is opened, the solenoid valve 120
When opened, negative pressure acts on the air passage 30b communicating with the annular grooves 30a, 32a and the vertical groove 32b, and the annular groove 30a
.

Air in the vertical grooves 32a and 32b is sucked through the air passage 30b. Further, when the solenoid valve 117 is opened after a delay of about 0.1 seconds to 1 second, preferably 0.3 seconds to 0.5 seconds, the gas in the cavity 35 is released from the gas vent path 85.
．． The gas inside the cavity 35 is sucked through the exhaust hole 105 through the gas vent groove 86 and the bypass 93, and is exhausted. In this way, by suctioning from both the plunger 59 side and the gas venting device 87 side, the inside of the cavity 35 and the injection sleeve 58. Plunger tip 59a
Although the vacuum level is the same in the gaps, etc., by suctioning the plunger 59 side slightly faster and making the vacuum level on the plunger 59 side larger than the vacuum level on the gas venting device 87 side, the vacuum level shown in Fig. 4 is obtained. As shown, the solidified layer 9 is strengthened by closely adhering to the end face of the plunger chip 59a and the four annular parts around it, and is also cooled to 300 to 400°C as the plunger chip 59a is cooled, so that the solidified layer 9 is strengthened. becomes thicker. As a result, the injection sleeve 58.

Intrusion of outside air through the gap with the plunger chip 59a is blocked. Further, the molten metal does not enter the cavity 35 before the molten metal is injected.

After creating a vacuum inside the cavity 35 in this way, the injection operation begins, and when the plunger tip 59a is advanced while degassing, the molten metal 127 in the casting sleeve 58 flows between the fixed sleeve 38 and the constriction 36. It is injected into the cavity 35 through the diameter. Plunger tip 59a
As the solidified layer 9 advances, it is pushed upward by the plunger tip 59a, and the upper end of the solidified layer 9 comes into contact with the flat surfaces 30c and 32c in front of the constriction 36, but the annular grooves 30a and 32
Air is sucked from the sleeve 38.a and both sleeves 38.
By providing the tapered part and the packing 38b at the joint part of the casting sleeve 58, outside air does not enter, and the cylindrical part of the solidified layer 9 is tightly attached to the inner peripheral surface of the casting sleeve 58 without separating from the plunger tip. 59a, and its tip is on the plane 30C132c in front of the constricted part 36'
! Contact with I. As the plunger tip 59a further rises, the solidified PFJ9 is crushed between the end face of the plunger tip 59a and the flat surfaces 30c and 32c of the mold 30.32, and the solidified layer 9 is broken, but the inside of the cavity 35 is Even if the vacuum is drawn from above, air does not enter from the injection sleeve as described above, so the cavity 35 is filled with the molten metal 127, with no air entering the molten metal and no turbulence in the flow of the molten metal. Then, this molten metal 127 rises in the gas vent groove 86 and comes into contact with the lower surface of the valve body 101a together with the gas.

At this time, the impact applied to the valve body 101a is larger than the impact applied to the valve body 101a because the mass of the molten metal 127 is extremely large compared to the mass of the gas and has large inertia, and the valve body 101a is compressed by the pole 102. The valve element 101a closes the valve seat 94 by rising while compressing the spring 103. Therefore, even if the molten metal 93 is blocked from flowing out from the valve seat 94 and mixes with the gas in the gas venting path 85 and the gas venting groove 86 and hits the valve element 101a discontinuously in the form of droplets, the molten metal can be removed once. Since the valve element 101a pushed up by the valve element 93 is pulled upward by the tension spring 97, the upper position is maintained and the exhaust passage is reliably closed by the valve element 101a.

After pressurizing and cooling for a predetermined time with the valve body 101a closed, the movable mold 32 is opened and the cylinder 89 of the gas venting device 87 is opened.
The spool 91 is raised to disengage from the movable mold 32 and the product is taken out from the cavity 35.

Note that when the spool 91 rises, only the spool 91 rises due to separation resistance between the valve body 101a and the solidified metal, and the valve stem 101 rises with a delay.
The pole 102 that had come off from the groove 101b of No. 1 is again connected to the IJ.
10 lb, and preparation for the next casting is completed. Further, at the upper limit of the rise of the spool 91, the return rod 96 contacts the stopper 104 and pushes down the valve rod 101, so that the valve body 101a is reliably opened and ready for the first casting.

In addition, in the above embodiment, the vertical groove 32b is replaced with the annular groove 30a, 3
2a so that vacuum suction can be drawn from them at the same time.
It is also possible to provide it separately without communicating with a and vacuum suction from both separately. In that case, the annular groove 30a
, 32a, the plunger tip 59a
The vacuum suction from the vertical groove 32b is preferably performed at the same time as the vacuum suction from the cavity 35. Also, the vacuum suction from the vertical groove 32b is performed immediately after the start of injection when the molten metal is drawn into the constricted portion 36. It is also good to do this immediately after starting to pass through, but in this case, vacuum suction is performed from the catty 35 after vacuum suction is performed from the vertical yI 32b.

By the way, normal aluminum products are 40~80c.
c/100g Al, but if the degassing device 2187 is used, the gas will be 5 to 10cc/100g A, and a high quality product with a pressure resistance of 100 to 150 Kg/crn' can be obtained.

In general, heat treatment becomes possible when the gas content is less than 5 cc/100g A.
When this happens, welding becomes possible, but if the inside of the cavity 35 is evacuated and the injection sleeve is also evacuated, an injection product that can be heat treated and welded can be obtained. In addition, this can be achieved not only by using new materials but also by using return materials.

Note that the position where the vacuum suction is started before the suction of the vacuum suction device starts is not limited to the above embodiment.

For example, it may be placed at any position below the level of the molten metal, such as around the fixed sleeve.

Effects of the Invention As is clear from the above description, according to the present invention, a vacuum suction port is provided in the air inlet portion located below the upper surface of the molten metal in the mold cavity, and the vacuum suction is performed at least as low as 0. .Vacuum suction is performed one second before the mold cavity, and then the molten metal is poured by vacuum suction from the mold cavity, so air is not sucked into the cavity.
Further, the solidified layer does not enter the cavity, and the product does not have cavities or pinholes, so the quality of the product can be significantly improved.

[Brief explanation of drawings]

Figures 1 to 11 show one embodiment of the apparatus for carrying out the method of the present invention, in which Figure 1 is a circuit diagram of a vacuum suction system, Figure 2 is a longitudinal sectional view, and Figure 3 is a diagram of a vacuum suction system. Fig. 1 is a view in the direction of arrow A, Fig. 4 is an enlarged sectional view of the casting sleeve and plunger,
Figure 5 is a sectional view taken along line V-V in Figure 4, and Figure 6 is a cross-sectional view of Figure 4.
- ■ line cross section 1 zo m 7
Figure 10 is a cross-sectional view of the gas venting device, Figure 11 is a cross-sectional view taken along the line XI-XI of Figure 10, and Figure 12 is a vertical cross-sectional view of a conventional casting sleeve. be. 30... Fixed mold, 32... Movable mold, 30
a, 32a... annular groove, 32b... vertical groove, 35... mold cavity. 38... Fixed sleeve, 55... Injection cylinder,
59... Injection sleeve, 59a... Plunger chip, 87... Gas venting device, 108... Pump, 112
...Vacuum tank, 127...Molten metal.

Claims (1)

[Claims] Connect the air inlet part located below the top surface of the molten metal in the mold cavity or casting sleeve to a vacuum source, and at least 0.1 seconds before the degassing device starts vacuum suction in the mold cavity. A casting method for a vertical casting type die casting machine, characterized in that vacuum suction is performed from the air entry portion, and then vacuum suction is performed from the mold cavity to cast the molten metal.