JPH08117960A - Oxide removing method and oxide removing device for die casting - Google Patents

Abstract

PURPOSE: To decrease the amt. of the oxides to be intruded into products at the time of high-pressure casting of an aluminum alloy or magnesium alloy, etc. CONSTITUTION: A molten metal buffer plate 61 which has a lacked circle part and is provided with a weir 63 on the side opposite to this lacked circle part is held at a suitable height of an injection sleeve. The molten metal is once fed from a ladle 68 toward this molten metal buffer plate 61 and the molten metal buffer plate 61 is vised according to rising of the molten metal 64, thereby the molten metal buffer plate 61 is exposed and the oxides 66 are captured before completion of feeding. The molten metal buffer plate is simultaneously rotated half as it is and the remaining oxides 66 are removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxide removing method and an oxide removing apparatus for a die casting for obtaining a cast product having less oxide mixed therein and excellent in mechanical properties.

[0002]

2. Description of the Related Art FIG. 16 is a front view of a conventional biscuit. An injection molding device such as a die casting machine is equipped with a fixed mold mounted on a fixed plate and a movable mold mounted on a movable plate, and a cavity is formed at a joint portion between these molds that are clamped. Has been formed. In addition, a fixed sleeve, which communicates with the cavity through a gate, is fitted in the sleeve hole of the fixed mold, and the injection sleeve of the injection cylinder supported on the fixed plate side is attached to and detached from this fixed sleeve. Freely joined. With this structure, when the molten metal is supplied to the injection sleeve and joined to the fixed sleeve, the plunger tip provided in the injection cylinder is hydraulically advanced, and the molten metal in the injection cylinder is pushed, the molten metal is It is injected into the cavity through the fixed sleeve and the gate.

Since the molten metal in the cavity is solidified to form a product, the mold is opened to take out the product. At this time, the surplus casting material is separated from the product in the injection sleeve and the gate. Be done. That is, when the molten metal solidifies, a large-diameter, thin-cylindrical molten solidified material, commonly called a biscuit, remains in the mold cavity, and a small diameter that also protrudes from the center of the molten molten metal solidified in the gate. A columnar molten metal solidified substance remains (hereinafter, the entire cast surplus material composed of the molten metal solidified substance in the sleeve and the molten metal solidified substance in the gate is called a biscuit. Further, the molten metal solidified substance in the sleeve is the large-diameter member 82. The solidified material in the gate is referred to as a small diameter member 83). When casting, non-metallic inclusions such as oxides of the molten metal enter the cavity, so that the quality of the product deteriorates. Therefore, in general, the wire mesh indicated by reference numeral 84 in FIG. 10 is loaded in the gate every shot. Sometimes. Then, this wire net is left embedded in the small diameter member. The biscuit 81 is separated from the cast product thus produced.

[0004]

However, when the metal net is loaded into the gate from below as in the prior art, and the aluminum alloy poured into the injection sleeve is pushed up by the plunger tip to fill the mold cavity, The oxides and non-metallic inclusions on the surface of the molten metal prevent part of the mixture inside the product by the metal net 84, but the remaining oxides and non-metallic inclusions are finely crushed by the metal net 84 and filled in the cavity together with the molten metal. It Therefore, good mechanical properties were obtained. However, the conventional biscuit 81 is integrally formed with the large-diameter member 82 and the small-diameter member 83 as described above, and the wire net 8 is attached to the small-diameter member 83 that is solidified in the gate.
Since 4 was left buried, there was a problem that the yield of the material was poor because it could not be recovered and reused as it was.

In view of the above conventional problems, the present invention has an object to provide a hot water supply method and an oxide removing apparatus in which the amount of oxides mixed into the product during high pressure casting of aluminum alloys or magnesium alloys is small. It is a thing.

[0006]

In order to solve such a problem, according to the first aspect of the present invention, a molten metal buffer plate having a circular cut portion between vertical injection sleeves, and a portion facing the circular cut portion. Using an oxide removing device that can move up and down coaxially with the injection sleeve by disposing a weir having an appropriate arc on the same molten metal buffer plate, and in a state of being positioned at an appropriate height inside the injection sleeve. The hot water is supplied from above, and the molten metal buffer plate is moved up at the same time as the molten metal surface rising speed so that the molten metal surface is above the buffer plate before the completion of hot water supply. At the same time, the oxide is captured in the part exposed from the surface of the molten metal, and at the same time, the buffer plate is rotated halfway to replace the part where the oxide is not captured, and then it is pulled up to oxidize the residual oxide on the buffer plate. The product is taken together with the molten metal buffer plate. To Suyo, in the second invention, the molten metal buffer plate having the arcuate shape of the gap between the vertical injection sleeve,
A molten metal buffer plate provided with a weir having an appropriate circular arc on the opposite side of the gap having a circular shape was fixed to the tip of a moving shaft that moves up and down coaxially with the injection sleeve. Further, in the third aspect of the invention, the molten metal buffer plate having the cutout portion is provided in a multi-stage manner on the moving shaft that moves up and down coaxially with the injection sleeve.

[0007]

Operation: The molten metal buffer plate having the cutout portion is inserted into the injection sleeve in a state in which the plate is downward, and is positioned at a predetermined height.
Next, when the molten metal is supplied from the ladle to the injection sleeve,
The molten metal accompanied by oxides during hot water supply falls onto the molten metal buffer plate or passes through the cutout portion to flow down the inner wall surface of the injection sleeve in a straightening manner and is stored in the injection sleeve.

Therefore, the molten metal supplied into the injection sleeve is prevented from scattering with turbulence, and the molten metal is less likely to be newly oxidized in the injection sleeve. When the molten metal buffer plate is positioned so as to cross the molten metal surface when the hot water supply is completed, the molten metal buffer plate is rotated halfway to capture oxides on the molten metal buffer plate, and when the molten metal buffer plate is pulled up further, the molten metal buffer plate Is oscillated horizontally or vertically so that only the molten metal mixed between the oxides is returned into the injection sleeve. Therefore, a cast product can be obtained in which oxide removal is easy and the amount of oxide inclusion is small.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a method for removing oxides from a die cast and an apparatus for removing oxides according to the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a sectional view of an oxide removing apparatus according to an embodiment of the present invention, FIG. 2 is a plan view seen from AA of FIG. 1, and FIG.
4 is an oxide removing apparatus showing another embodiment of the present invention, FIG.
Is a plan view seen from BB of FIG. 3, FIGS. 5 and 6 are plan views of still another oxide removing apparatus, FIG. 7 is a development view of various weirs attached to the molten metal buffer plate, and FIGS. Figure 11
Is an explanatory view of a method for removing oxides mixed when hot water is supplied to the injection sleeve according to the embodiment of the present invention, and FIG. 12 is a cross-sectional view of a molten metal buffer plate having a cutout portion provided in multiple stages in the same direction,
FIG. 13 is a cross-sectional view when a molten metal buffer plate having a cutout portion is provided in multiple stages in the opposite direction, FIG. 14 is a front view of a vertical casting die casting machine, and FIG. 15 is a vertical cross-sectional view of a vertical injection device. Is.

14 and 15, a pit 1 having a rectangular shape in plan view is provided below the floor surface, and a pair of machine bases framed by steel plates or shaped steels are provided at both ends of the pit 1. 2 is extended upright on the floor surface, and a stationary platen 3 formed in a substantially square shape is placed on one end of these machine bases 2 and its legs 3a are bolted. It is fixed.

An end platen 4 is erected and fixed to the other end of the machine base 2 so as to be movable and adjustable. The fixed platen 3 and the end platen 4 are formed by four tie rods 5 at four corners. After being connected and adjusted for movement, they are fixed with a nut 6. Numeral 7 is a movable platen which is fitted into the tie rods 5 at the four corner holes so as to be able to move forward and backward with respect to the fixed platen 3. The movable platen 7 is provided between the piston rod 9 of the mold clamping cylinder 8 and the toggle mechanism 10. The piston plate 9 is moved forward and backward by hydraulic pressure to move forward and backward with respect to the fixed platen 3.

A fixed mold 11 having cavities 11a and 12a and a biscuit portion 15 and a movable mold 12 are mounted on the fixed platen 3 and the movable platen 7, respectively, and are driven by a mold clamping cylinder 8 to move the movable platen. As the mold 7 advances from the mold open state, mold clamping is performed as shown in FIG.

Next, the vertical casting type injection device 13 arranged in the pit 1 will be described. Reference numeral 20 denotes an injection cylinder pivotally supported by a seat 18 fixedly provided on the bottom surface of the pit 1 via a pin 19, and the injection cylinder 20, the docking frame 22, and the injection sleeve 24 are sequentially arranged from the lower side. It has a staircase configuration. A piston 26 is installed in the injection cylinder 20.
A rod 28 extending upward is connected to the.
The docking frame 22 is provided with a cylinder hole 30 extending in the vertical direction, a docking ram 32 is inserted into the cylinder hole 30, and the lower end of the docking ram 32 is a flange 34 formed on the upper surface of the injection cylinder 20.
It is stuck to.

The injection sleeve 24 is connected to the upper side of the docking frame 22 via a connecting member 36, and the upper end thereof can be inserted into the lower end of the biscuit portion 15. A plunger tip 38 is slidably installed in the injection sleeve 24, and a lower end of a plunger 40 holding the plunger tip 38 is a coupling 42.
It is connected to the upper end of the rod 28 via. A tilting cylinder 44 is pivotally supported by a side wall of the pit 1 via a seat 46 and a pin 48, and a rod 52 connected to a piston 50 of the tilting cylinder 44.
Has its tip pivotally attached to the side surface of the flange 34 of the injection cylinder 20 via a joint 54 and a pin 56.

Reference numeral 60 is an oxide removing device, which comprises a molten metal buffer plate 61, a moving shaft 62, and a weir 63.

The molten metal buffer plate 61 serves to straighten the molten metal 64 supplied from the ladle 68 without causing a turbulent flow such as a twist and to flow down the inner wall surface of the injection sleeve 24. The distal end of the moving shaft 62 is fixed in a direction orthogonal to the center of the molten metal buffer plate 61, and the other end of the moving shaft 62 is vertically moved in the axial direction of the injection sleeve 24 while being held by, for example, a robot not shown. It is possible.

Further, in this embodiment, as shown in FIG. 1, the molten metal buffer plate 61 has a cutout portion 61a on the outer peripheral portion thereof. When the molten metal 64 is supplied from the ladle 68 to the injection sleeve 24, the lacked circular portion 61a serves as a passage port for the molten metal 64. The size A1 of the lacked circular portion 61a is based on, for example, the injection sleeve cross-sectional area A0. If A1 / A0 = 3 ~
About 20% is desirable.

When A1 / A0 is 3% or less, ladle 6
The molten metal 64 supplied from 8 to the injection sleeve 24 does not flow down below the injection sleeve 24 through the cutout portion 61a and is held on the upper surface of the molten metal buffer plate 61 for a relatively long time. This is not desirable because the temperature will drop.

On the other hand, when A1 / A0 becomes 20% or more, the molten metal 64 supplied from the ladle 68 to the injection sleeve 24 smoothly passes through the missing circle portion 61a and flows down below the injection sleeve 24. A turbulent flow such as a twist is generated in the molten metal 64 during the flow, and the rectifying effect is halved, which is not desirable.

A weir 63 for efficiently trapping the oxide 66 is provided on the outer peripheral end surface of the molten metal buffer plate 61 on the opposite side of the cutout portion 61a. The height of the central portion of the weir 63 is preferably 1 to 5 mm, more preferably 2 to 4 m.
It is better to set m.

Although the shape of the weir 63 is shown in FIGS. 7 (1) to 7 (4), other weirs 63 may be used.

Further, the mounting width of the weir 63 will be described using the angle θ as shown in FIG. 2, for example, θ = 70 ° to 13 °
About 0 ° is desirable, and when θ = 70 ° or less, the oxide 66 trapped in the molten metal buffer plate 61 is again entrained in the molten metal 64 and flows out, and the trapping rate of the oxide 66 is reduced.

On the contrary, when θ = 130 ° or more, the oxide 6
Although the trapping rate of No. 6 increases, the molten metal 64 is also trapped at the same time, and the relative trapping rate of the oxide 66 still decreases. In addition, the oxide 66 trapped on the molten metal buffer plate 61
In the last step, it becomes difficult to remove it by blowing it away with the compressed air 67.

Further, as the shape of the molten metal buffer plate 61, the same results can be obtained by using the shapes shown in FIGS. 3, 5, and 6, but other shapes are also included in the present invention. .

In the present embodiment, the holding height H2 of the molten metal buffer plate 61 inside the injection sleeve 24 during hot water supply is set to be 3/5 to 4/5 of the height H1 of the injection sleeve 24. The drop of the molten metal 64 from the hot water supply position of the ladle 68 to the molten metal buffer plate 61 is small, and the generation of bubbles in the molten metal 64 may be small.

As the material of the oxide removing device 60, for example, a metal, a nonmetal, or a composite material thereof which does not melt against the molten metal 64 such as an aluminum alloy or a magnesium alloy is used.

Injection sleeve 24 constructed as described above
The removal of the oxide in the molten metal 64 supplied to the hot water is performed as follows. Here, the molten metal buffer plate 61 as shown in FIGS. 1 and 2 will be described as a representative.

First, the movable platen 7 is advanced by the mold clamping cylinder 8 to clamp the molds 11 and 12, and then, as shown in FIG.
As shown in (4), the rod 52 of the tilt cylinder 44 is advanced to tilt to the chain line position, and the lubricant is spray-supplied to the injection sleeve 24 from a lubricant spray position (not shown). Then, a gripping device such as a robot (not shown) is used to remove the oxide 60.
While holding the moving shaft 62 of the molten metal so as to be positioned coaxially with the injection sleeve 24, the molten metal buffer plate 61 is lowered in the axial direction of the injection sleeve 24, and the molten metal buffer plate 61 and the injection sleeve 2
4 so that there is a uniform annular gap 70 between them, and as shown in FIG. 8, the height H2 of the molten metal buffer plate 61 inside the injection sleeve 24 is set to the height H1 of the injection sleeve 24.
Position so that it becomes, for example, 3/5 (FIG. 8).

Next, for example, an aluminum alloy molten metal 64 is pumped from a molten metal holding furnace (not shown) by a ladle 68, and then the molten metal 64 is gently fed onto the molten metal buffer plate 61 having a small head while tilting on the injection sleeve 24. When you start
The molten metal 64 is rectified on the inner wall surface of the injection sleeve 24 from the cutout portion 61a, flows down, is replaced with air, and is gradually stored in the injection sleeve 24. Molten metal 64 is missing circle 61
When flowing from a into the injection sleeve 24, the molten metal 64
The swirl of the air as slow as possible to prevent the entrainment of air,
Moreover, the inclusion of the oxide 66 in the molten metal 64 is also reduced.

Subsequently, the molten metal buffer plate 6 is inserted into the injection sleeve 24.
When the molten metal 64 is supplied through the nozzle 1, the surface of the molten metal 64 gradually increases, and the residual air in the injection sleeve 24 is also replaced with the molten metal 64 and discharged from the annular gap 70 (FIG. 9). Molten metal 6 stored in the injection sleeve 24
As the molten metal surface of No. 4 gradually approaches the molten metal buffer plate 61, the moving shaft 62 is gradually pulled up while maintaining the current state so as to reduce the air pool 71 generated on the lower surface of the molten metal buffer plate 61. .

While hot water is being supplied to the injection sleeve 24, the molten metal buffer plate 61 is raised while being careful that the scene of the molten metal 64 is constantly positioned above the molten metal buffer plate 61.

When the hot water supply to the injection sleeve 24 is completed, the molten metal buffer plate 61 is slightly pulled up to
When the left half of the molten metal buffer plate 61 is exposed from the molten metal surface and the molten metal surface of the molten metal 64 in the intersecting direction, the oxide 66 floating on the molten metal surface of the molten metal 64 is captured by the molten metal buffer plate 61. .

The right half of the molten metal buffer plate 61 on the side having the intermittent circle portion 61a is still immersed in the molten metal 64, and the oxide 6 is placed on the molten metal buffer plate 61 of the right half.
6 remains floating on the surface of the molten metal and is not captured (Fig. 1).
0).

When the molten metal buffer plate 61 is rotated halfway in the above state and then pulled up, the oxide 66 is placed on the molten metal buffer plate 61 on the side where the weir 63 is provided, and the remaining oxide 66 is also captured. It

Thus, the oxide 6 is formed on the upper surface of the molten metal buffer plate 61.
After being pulled up integrally from the injection sleeve 24 in a state where 6 is captured, it moves to an appropriate position as it is.

Oxide 66 trapped on the molten metal buffer plate 61
After the oxide removing device 60 is moved to an appropriate position, it is removed by blowing compressed air 67 or the like.
(FIG. 11). Although the case where the compressed air 67 is used to remove the oxide 66 by spraying has been described, nitrogen gas or the like may be sprayed.

Further, the case where the oxide 66 is removed and the case where the compressed air 67 is blown has been described.
May be removed by external heating, vibration, suction or grasping.

Although the molten metal buffer plate 61 having the shape shown in FIGS. 1 and 2 is used in this embodiment, the molten metal buffer plate 6 is used as shown in FIGS. 12 and 13.
When 1 is provided in multiple stages, the capture rate of the oxide 66 is further improved.

FIG. 12 shows the case where the cutout portions 61a are provided in the same direction in multiple stages (two stages in the embodiment). With such a structure, the direction in which the molten metal 64 enters and the injection sleeve 24 are formed.
Since the direction of venting gas inside is fixed, air trap 7
1 is less likely to occur and is an excellent method.

Further, in FIG. 13, the cutouts 61a are provided in a multi-stepped shape (two steps in this embodiment) in the opposite direction. With such a structure, the molten metal buffer plate 61 in the upper step has a degassing direction. Since the entering direction of the molten metal 64 is determined, the air pool 71 is unlikely to occur, but the molten metal buffer plate 6 in the lower stage
In No. 1, the molten metal 64 flowing down from the molten metal buffer plate 61 in the upper stage
Is an annular gap 7 between the injection sleeve 24 and the molten metal buffer plate 61.
Although it is easy to prevent the smooth escape of gas in the passage of the gas escaping from 0, the capture rate of the oxide 66 is considerably improved.

On the other hand, when the pouring into the injection sleeve 24 is completed, pressure oil is introduced to the piston rod 52 side of the tilt cylinder 44 to erect the injection device 13. Next, when pressure oil is introduced into the cylinder hole 30, the docking frame 22 starts to rise at a predetermined speed to bring the injection sleeve 24 into contact with the fixed sleeve 58. Further, pressure oil is introduced to the head side of the piston 26 to raise the plunger tip 38 and raise the molten metal 64 into the injection sleeve 24. Finally, pressure oil is introduced into the injection cylinder 20 to further raise the plunger tip 38, and the molten metal 69 is introduced into the cavities 11a and 12a.
Is filled. Molten metal 64 into the cavities 11a, 12a
After the solidification is completed, the plunger tip 38 and the docking frame 22 are lowered, tilted to the chain line position shown in FIG. 15, and the molds 11 and 12 are opened to take out the cast product in the cavities 11a and 12a. Complete the cycle. The product and the biscuit 81 are cut and separated in a later process.

[0043]

As is apparent from the above description, in the first invention according to the present invention, a molten metal buffer plate having a cutout portion between vertical injection sleeves and the same melt facing the cutout portion. A dam having an appropriate circular arc is arranged on the buffer plate, and an oxide removing device that can move up and down coaxially with the injection sleeve is used, and hot water is supplied from above in a state of being positioned at an appropriate height in the injection sleeve. Then, the molten metal buffer plate is caused to flow down through the aforesaid circular portion, and the molten metal buffer plate is raised in accordance with the rising speed of the molten metal, so that the molten metal surface is positioned above the buffer plate before the completion of hot water supply. At the same time as capturing the oxide in the part exposed from the surface, the buffer plate is rotated halfway and replaced with the part not capturing the oxide, and then the oxide remaining on the buffer plate is removed by pulling it upward. I will take it out together with the molten metal buffer plate In the second invention, a molten metal buffer plate having a gap between the vertical injection sleeves and a dam buffer plate provided with a weir having an appropriate arc on the opposite side of the gap. It is fixed to the tip of a moving shaft that moves up and down coaxially with the injection sleeve. Further, according to the third aspect of the invention, the molten metal buffer plate having the cutout portion is provided on the moving shaft that moves up and down coaxially with the injection sleeve in a multi-stage manner, so that the inclusion of outside air and oxides in the molten metal is prevented. Because you can
A cast product with extremely excellent quality can be obtained as compared with the conventional cast product. Further, since the wire mesh is not buried in the biscuit portion, the surplus casting material (biscuit) can be effectively used, and the yield is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an oxide removing device according to an embodiment of the present invention.

FIG. 2 is a plan view as seen from AA of FIG.

FIG. 3 is an oxide removing apparatus showing another embodiment of the present invention.

FIG. 4 is a plan view seen from BB of FIG.

FIG. 5 is a plan view of another oxide removing apparatus.

FIG. 6 is a plan view of still another oxide removing apparatus.

FIG. 7 is a development view of weirs of various shapes attached to the molten metal buffer plate.

FIG. 8 is an explanatory diagram showing a state before starting hot water supply.

FIG. 9 is an explanatory diagram of a method of removing oxides mixed when hot water is supplied to the injection sleeve according to the embodiment of the present invention.

FIG. 10 is an explanatory diagram illustrating a subsequent operation illustrated in FIG.

11 is an explanatory diagram illustrating a subsequent operation illustrated in FIG.

FIG. 12 is a cross-sectional view when a molten metal buffer plate having a cutout portion is provided in multiple stages in the same direction.

FIG. 13 is a cross-sectional view of a molten metal buffer plate having a cutout portion provided in multiple stages in the opposite direction.

FIG. 14 is a front view of a vertical casting die casting machine.

FIG. 15 is a vertical sectional view of a vertical injection device.

FIG. 16 is a front view of a conventional biscuit.

[Explanation of symbols]

 3 Fixed Platen 4 End Platen 5 Tie Rod 10 Toggle Mechanism 11 Fixed Die 12 Movable Dies 11a, 12a Cavity 13 Injection Device 15 Biscuit Part 20 Injection Cylinder 22 Docking Frame 24 Injection Sleeve 32 Docking Ram 38 Plunger Chip 40 Plunger 44 Tilt Cylinder 60 Oxide removal device 61 Molten metal buffer plate 61a Missing circular portion 62 Moving shaft 63 Weir 64 Molten metal 66 Oxide 67 Compressed air 68 Ladle 70 Annular gap 71 Air pool

Claims (3)

[Claims] 1. A molten metal buffer plate having a cutout portion between vertical injection sleeves, and a dam having an appropriate arc on the same molten metal buffer plate facing the cutout portion, and coaxial with the injection sleeve. Using an oxide removing device that can move vertically in the direction, hot water is supplied from above while being positioned at an appropriate height inside the injection sleeve,
While flowing down through the cutout portion, the molten metal buffer plate is raised in accordance with the molten metal level rising speed, and the molten metal surface is positioned above the buffer plate before the completion of hot water supply. At the same time as capturing the oxide in the exposed part, the buffer plate is rotated halfway and replaced with the part not capturing the oxide, and then it is pulled upward to absorb the oxide remaining on the buffer plate into the molten metal buffer. A method for removing oxides from a die cast, characterized in that the oxide is removed integrally with the plate. 2. A molten metal buffer plate having a gap between the vertical injection sleeves, and a molten metal buffer plate provided with a weir having an appropriate arc on the opposite side of the gap. An oxide removing device characterized in that it is fixed to the tip of a moving shaft that moves up and down coaxially with a sleeve. 3. A device for removing oxides, wherein the molten metal buffer plate having the cutout portion according to claim 1 is provided in a multi-stage manner on a moving shaft that moves up and down coaxially with the injection sleeve.