JP2000246417A - Low speed filling die casting method and apparatus thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low speed filling die casting and an apparatus thereof, with which a runner having the sufficient cross sectional area to make the directional solidification without entrapping the air in the injecting process, is provided and the oxidizing film of molten metal is not mixed into a cavity. SOLUTION: In the die casting method, with which the molten metal 7 is pushed up in the vertical direction and filled into the cavity 2 in a die 5 from the inlet 4 of the runner in the orthogonal direction to the vertical direction through the runner 3 at the low speed, a process for filling the molten metal 7 into the cavity 2 at least in the state interposing a weir 6 in the runner inlet 4, is provided. The oxidizing film 7a on the upper surface of the molten metal 7 does not flow into the cavity 2 with the existence of the weir 6, and the rising-up of the molten metal 7 at the runner inlet 4 becomes remarkably high with the weir 6 in comparison with no weir 6, and the molten metal 7 flows out from the lower end part of the rising-up of the molten metal 7 and gradually flows in the cavity 2 through the runner 3 from the runner inlet 4 and the filling of the molten metal 7 is completed before the oxidized film 7a flows into the cavity 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-speed filling die-casting method and apparatus, and more particularly to a low-speed filling die-casting method and apparatus such as molten forging and laminar flow die casting.

[0002]

2. Description of the Related Art In a vertical injection casting method (hereinafter, collectively referred to as a low-speed filling die casting method) such as a low-speed laminar flow die casting and a vertical injection molten forging, an upper pouring ladle is used as a pouring method currently used for mass production. A method, a bottom pouring method using a long nose ladle, and a pouring method using an electromagnetic pump or air pressurization are known. In any molten metal injection method, it is indispensable to apply a lubricant to the inner surface of the injection sleeve on which the injection piston that pushes up the molten metal slides. For this reason, the moisture and the organic binder contained in the lubricant react with the molten metal or Hydrolyzes together with the gas to form a thin oxide film on the upper surface or surface layer of the molten metal in the injection sleeve and collects. When this oxide film enters a cast product, the mechanical performance of the cast product is significantly reduced, and this causes a leak particularly when the cast product is an airtight component.

In a low-speed filling die-casting method having a multi-cavity mold, a mold 52 is generally formed by an upper mold 50 and a lower mold 51, as shown in FIG.
The molten metal 56 in the injection sleeve 55 is injected into the injection piston 57 through the runner 54 into one or more cavities 53 of the injection piston 57.
In order to remove the oxide film of the molten metal 56 at the time of pouring and pouring, a filter 5 such as a wire mesh is inserted into the runner inlet 58.
9 has been installed. In FIG. 6, reference numeral 60 denotes a division surface of the mold 52, and reference numeral 61 denotes an extrusion pin inserted into an insertion hole for extruding a cast product.

When the injection piston 57 is actuated to push up the molten metal 56 in the injection sleeve 55 and pour it into the cavity 53, the oxide film is filtered or cut into small pieces by a filter 59 installed at the runner inlet 58. The molten metal 5 in the cavity 53 via the runner 54
6, and the adverse effect of the oxide film is prevented. However, when the filter 59 is installed at the runner inlet 58, the filter material is separately required, and the production cost of the cast product as a whole is reduced, such as a decrease in the casting cycle and an increase in the material cost due to the contamination of the filter material as impurities. Will increase.

A basin 63 is provided on the shunt 62 above the injection sleeve 55, and the oxidized film of the molten metal 56 is captured by the basin 63. Although a method of preventing the molten metal 56 from entering the inside 53 is also performed, in this method as well, when the height of the runner inlet 58 exceeds 15 mm, the swelling height of the molten metal 56 at the runner inlet 58 is insufficient. Because of this, the oxide film of the molten metal 56
3 cannot be kept inside, and the oxide film
Through the cavity 53.

[0006] In the low-speed filling die-casting method, there is no air entrainment due to turbulence during the injection process, and the pressure of the pressurizing piston is transmitted into the cavity 53 during the solidification process.
Since so-called directional solidification must be performed, the runner inlet 58 needs to have a sufficient cross-sectional area to satisfy these two conditions, that is, a sufficient height and width. Therefore, in many cases, the height of the runner inlet 58 must be higher than the swelling height of the molten metal 56, that is, more than 15 mm.
It is difficult to keep the oxide film of the molten metal 56 in 3.

As described above, the conventional method for preventing the inflow of the oxide film of the molten metal 56 into the cavity 53 has many problems, and the filter 59 is installed at the runner inlet 58 in consideration of high cost. However, there is no choice but to allow some oxide film to enter the cavity 53, and a method has been found to prevent the oxide film from entering the cavity 53 and maintain high quality without adding cost. Did not.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems in low-speed filling die casting, and has an object to prevent air from being trapped by turbulence in an injection process. With a runner inlet with sufficient height and width to achieve directional solidification,
Another object of the present invention is to provide a low-speed filling die-casting method and apparatus capable of maintaining good casting quality by preventing the oxide film of the molten metal from entering the cavity, and achieving these without increasing the manufacturing cost. is there.

[0009]

According to the present invention, there is provided a low-speed filling die-casting method according to the present invention.
In the die casting method in which the molten metal is pushed up in the vertical direction and the molten metal is slowly filled into the cavity of the mold via the runner through the runner inlet in the direction orthogonal to the vertical direction, the weir is interposed in the runner inlet. A step of filling the cavity with the molten metal, wherein the oxide film present on the upper surface of the molten metal is prevented from flowing into the cavity by the weir.

[0010] The low-speed filling die-casting method according to claim 2 comprises:
2. The shunt according to claim 1, wherein a shunt located above the injection piston for pushing up the molten metal in a vertical direction is provided with a basin at least 3 to 20 mm higher than an upper end of the runner inlet, and when filling the cavity with the molten metal, The method further includes a step of capturing the oxide film in the water pool so that the oxide film is prevented from flowing into the cavity.

The low-speed filling die-casting method according to claim 3 is characterized in that, in claim 1 or 2, the weir exits from the runner entrance immediately before or immediately after the completion of filling the molten metal into the cavity.

[0012] A low-speed filling die-casting apparatus according to claim 4 of the present invention has a mold having runners each communicating with one or more cavities, the runners having runner inlets extending in a direction perpendicular to the vertical direction; At least a weir provided at the mold positioned at the runner inlet, and when the molten metal is filled into the cavity from the runner inlet via the runner, the weir is present on the upper surface of the molten metal by the weir. The low-speed filling die-casting apparatus according to claim 5 is characterized in that the film is prevented from flowing into the cavity. In claim 4, the weir is movable and the height of the weir can be adjusted. .

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 5 are longitudinal sectional views of an operation state of a low-speed filling die casting apparatus showing an embodiment of the present invention. The same components as those in the related art are denoted by the same reference numerals. 1 to 5, a low-speed filling die casting apparatus 1
Has a runner 3 that communicates with one or more cavities 2, and the runner 3 has a runner inlet 4 in a direction perpendicular to the vertical direction, and a die 5 positioned at the runner inlet 4. At the time of filling the molten metal 7 into the cavity 2 from the runner inlet 4 through the runner 3, the weir 6 removes the oxide film 7 a existing on the upper surface of the molten metal 7 from the cavity. 2 so as not to flow into.

The mold 5 is divided into a fixed lower mold 10 and a movable upper mold 11 at a dividing surface 60. In this embodiment, the mold 5 is shown with two cavities 2, but even if there are four cavities 2,
The present invention may be applied without limitation to the number or the number, and the number is not limited.

The lower mold 10 pushes up the molten metal 7 and
An injection piston 12 for injection into the injection sleeve 14 is slidably provided in an injection sleeve 14 facing the biscuit 13. The lower mold 10 is provided with a runner 3 for communicating between the biscuit 13 and two or more cavities 2. The lower mold 10 is set on a fixed platen 15.

The upper mold 11 is attached to the movable platen 20 and is fixed by the movable platen 20 to the lower mold 10.
Can be opened and closed between The weir 6 installed at the runner inlet 4 facing the biscuit 13 is slidably inserted into the insertion hole 21 of the upper die 11, the upper part of the weir 6 is connected to the operating cylinder 22, and further, the diversion facing the biscuit 13. Child 2
3 is provided with a pool 24 at least 3 to 20 mm higher than the runner inlet 4. Before the injection and filling of the molten metal 7, the weir 6 is advanced to the advance limit by the operating cylinder 22, and the weir 6 is interposed at the runner inlet 4 (see FIGS. 1 to 4).

When the injection piston 12 is operated and the molten metal 7 is filled in the cavity 2 by interposing the weir 6 at the runner inlet 4, the weir 6 interposed at the runner inlet 4.
As a result, the molten metal 7 rises above the height of the runner inlet 4 in front of the runner inlet 4 (see FIGS. 2 to 5), is stored in the pool 24, flows out from the lower part of the raised molten metal 7, and the runner 3 is discharged from the runner inlet 4. As a result, the oxide film 7a existing on the upper surface of the molten metal 7 continues to be trapped in the pool 24, and the oxide film 7a is not mixed into the cavity 2 while being filled in the cavity 2 (see FIG. 2). The filling of the molten metal 7 into the cavity 2 is completed.

Before and after the end of injection filling, the injection piston 1
The operating cylinder 22 is operated by a retreat signal from a position meter (not shown) in the injection mechanism including the injection mechanism 2 to move the weir 6 to the retreat limit, that is, retreat the weir 6 from the runner inlet 4 (see FIGS. 4 and 5). . As a result, a sufficient cross-sectional area that the runner 3 originally has can be secured, and the pressure holding for the directional solidification of the molten metal 7 in the cavity 2 becomes easy.
The operating cylinder 22 is provided with limit switches (not shown) at the forward and backward limits of the weir 6, respectively.
The operation range of the weir 6 is regulated by these limit switches, and when an abnormality is found in its operation, the weir 6 is immediately stopped and the casting cycle is automatically stopped. Further, as the weir 6, a rod-shaped (pin-shaped) one having a diameter of 8 to 12 mm is preferably used.
The size, shape, and number of the runners 3 are determined according to the size, that is, the height and the width, and one or more runners 3 are installed at the runner entrance 4.

The upper die 11 is provided with an insertion hole 26 for inserting an extrusion pin 25 for taking out a product. The extrusion pin 25 is vertically moved by an extrusion board 27 in the insertion hole 26. I can do it. The insertion hole 26 is in direct contact with the cavity 2, and each of the push pins 25 inserted into the insertion hole 26 has a role of removing a product cast in the mold 5.
In addition to the above role, the gap between the 6 and the pushing pin 25 inserted therein has a role of venting air. Therefore, the insertion hole 26 is opened to the outside when the molten metal 7 is filled, and discharges the air in the cavity 2.

The number of the insertion holes 26 and the number of the push pins 25 can be appropriately changed, and the gap between them can be freely changed by changing the inner diameter of the insertion holes 26 and the outer diameter of the push pins 25. Therefore, the amount of air bleeding can be adjusted, and back pressure can be applied to the molten metal 7. Therefore, in the low-speed filling die-casting apparatus 1 of the present invention, only the gravity can be applied to the lower mold 10 in the process of injecting the molten metal 7. It is possible to improve the hot water circulation at 10 locations.

The operation of the low-speed filling die-casting apparatus 1 having the above structure will be described. First, a low-speed filling die-casting apparatus 1 provided with a weir 6 corresponding to the material and purpose of a casting product is selected, and a release agent is applied to the surface of the mold. After preparation for injection of molten metal such as coating, the movable platen 2 is operated to close the mold 5.
Next, the weir 6 is advanced to the forward limit by the operating cylinder 22, and the weir 6 is interposed at the runner inlet 4 (see FIG. 1).

Next, when the injection piston 12 is actuated to push up the molten metal 7 in the injection sleeve 14 to perform low-speed filling, the molten metal 7 tries to enter each cavity 2 from the biscuit 13 via each runner 3. However, before that, the molten metal 7 rises at the runner inlet 4 by the weir 6, and the oxide film 7 a on the upper surface thereof is captured by the pool 24, and while maintaining this state, the molten metal 7 is separated from the lower part of the molten metal 7. Filling the cavity 2 (see FIGS. 2 and 3), the oxide film 7a
Are completed without mixing into each cavity 2 (see FIG. 4).

Before and after the filling of the molten metal 7 is completed, the operating cylinder 22 is operated to retract the weir 6 to the retreat limit in accordance with the withdrawal signal from the position meter, the weir 6 is retracted from the runner inlet 4, and the injection piston 12 And pressurized to solidify the molten metal 7 in the cavity 2 in a directional manner (FIG. 5).
reference). After completion of the casting, the mold 5 is opened by operating the movable platen 20 after cooling, the extrusion board 27 is lowered, the extrusion pin 25 is lowered in the insertion hole 26, and the casting product is removed from the mold 5.

An embodiment for confirming the effect of the present invention will be described below. Example Using a JIS A390 aluminum alloy, using talc as a mold release agent, using a low-speed filling die-casting device as shown in FIGS. More than 300 car air conditioner compressor cylinder castings were cast.

Comparative Example Using a conventional low-speed filling die-casting apparatus shown in FIG. More than one piece was cast. Table 1 shows the leak rates caused by the inclusion of the oxide film in the cast products produced in the examples and comparative examples.

[0026]

[Table 1]

As shown in Table 1, the casting conditions of the car air conditioner compressor cylinder castings cast by the method of the present invention show that the height of the molten metal at the runner inlet reaches 35 mm and the runner inlet height is 15 mm.
In this case, the height of the molten metal increased by 20 mm, and the height of the raised molten metal did not become lower than the height of the runner inlet until the filling of the molten metal into the cavity was completed.

Therefore, there is almost no leak occurring in the cast airtight product due to the entrapment of the oxide film of the molten metal.
The leak rate was at most 0.3%. On the contrary,
In the conventional examples, the swell height of the molten metal at the runner inlet is 20 mm or less, and the runner inlet height is 15 mm or less.
In the case of mm, the maximum height was about 5 mm, but before the filling of the cavity was completed, the height of the swelling of the molten metal became lower than the height of the runner inlet, and the oxide film flowed into the cavity. As a result, the leak rate of the cast product resulting from the incorporation of the oxide film into the product increases, and the leak rate is at least 1.
5%, up to 2.0%.

Although the preferred embodiment of the present invention has been described above, the specific configuration is not limited to this, and changes and additions without departing from the gist of the present invention are within the scope of the present invention.

[0030]

As described above in detail, according to the first aspect of the present invention, the rise of the molten metal at the entrance of the runner becomes significantly higher than that without the weir due to the presence of the weir, and the molten metal rises from the lower end of the rise of the molten metal. Flows out and the molten metal gradually flows into the cavity from the runner inlet via the runner,
The height of the molten metal gradually rises, but before reaching the upper surface of the molten metal with the oxide film, the cavity is filled with the molten metal,
No oxide film is mixed with the molten metal in the cavity. Therefore, even if the cross-sectional area of the runner having a height and width sufficient to enable directional solidification while preventing air entrainment due to turbulence during the injection process is maintained, the oxide film of the molten metal does not enter the cavity. Therefore, good casting quality can be maintained, and there is almost no increase in production cost by this method.

According to the second aspect of the present invention, since the pool is 3 to 20 mm higher than the entrance of the runner, the oxide film of the molten metal can be reliably captured in the pool together with the function of the weir. Also, no oxide film is mixed with the molten metal in the cavity.

According to the third aspect of the present invention, since the weir is retreated from the runner inlet before and after the cavity is filled with the molten metal, the cross-sectional area of the runner entrance can be sufficiently secured, and the molten metal in the cavity can be directionally solidified. Can be maintained, and the quality of the casting can be further improved.

According to the fourth aspect of the present invention, the above-mentioned low-speed filling die-casting method can be realized efficiently, and a casting of good quality can be obtained. Improvements can also be achieved.

According to the fifth aspect of the present invention, when filling the cavity with the molten metal, the weir is interposed at the runner inlet so that the molten metal is raised to prevent the oxide film from being mixed into the cavity, and the cavity is filled with the molten metal. Then, the position of the weir can be adjusted as necessary, such as by removing the seki from the runner inlet and facilitating the pressure holding for directional solidification of the molten metal in the cavity, further improving the casting quality. be able to.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an operating state of a low-speed filling die casting apparatus of the present invention.

FIG. 2 is a longitudinal sectional view showing an operating state as in FIG.

FIG. 3 is a longitudinal sectional view showing the operating state as in FIG.

FIG. 4 is a longitudinal sectional view showing an operating state as in FIG.

FIG. 5 is a longitudinal sectional view showing the operating state as in FIG. 1;

FIG. 6 is a longitudinal sectional view showing an operation state of a conventional low-speed filling die casting apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Low speed filling die-casting apparatus 2, 53 Cavity 3, 54 Runner 4, 58 Runner inlet 5, 52 Die 6 Seki 7, 56 Molten 7a Oxide film 10, 51 Lower die 11, 50 Upper die 10 Upper die 11 Lower die 12, 57 injection piston 13 biscuit 14, 55 injection sleeve 15 fixed platen 20 movable platen 21 insertion hole 22 operating cylinder 23, 62 shunt 24, 63 water pool 25, 61 extrusion pin 26 insertion hole 27 extrusion board 59 filter 60 dividing surface

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Takashi Asahina, Inventor 5-11-3, Shimbashi, Minato-ku, Tokyo Sumi Light Technos Co., Ltd. (72) Inventor Sadayuki Kanayama 5-11-3, Shimbashi, Minato-ku, Tokyo Sumitomo Technos Co., Ltd.

Claims (5)

[Claims] 1. A die casting method in which a molten metal is pushed up in a vertical direction, and the molten metal is slowly filled into a cavity of a mold via a runner through a runner inlet in a direction perpendicular to the vertical direction. A low-speed filling die-casting method comprising the step of filling the cavity with the molten metal in a state where the molten metal has been made, and preventing the oxide film present on the upper surface of the molten metal from flowing into the cavity by the weir. 2. A shunt located above an injection piston for pushing up a molten metal in a vertical direction is provided with a basin at least 3 to 20 mm higher than an upper end of the runner inlet.
2. The low-speed filling die-casting method according to claim 1, further comprising the step of: trapping the oxide film in the pool when the molten metal is filled in the cavity, so as to prevent the oxide film from flowing into the cavity. . 3. The low-speed filling die-casting method according to claim 1, wherein the weir exits from the runner inlet immediately before or immediately after the completion of filling the molten metal into the cavity. 4. A mold having runners each communicating with one or more cavities, wherein the runner has a runner inlet in a direction perpendicular to the vertical direction, and the mold is located at the runner inlet and has a shape. At least when the molten metal is filled into the cavity from the runner inlet via the runner, so that an oxide film present on the upper surface of the molten metal is prevented from flowing into the cavity by the weir. A low-speed filling die-casting device. 5. The low-speed filling die casting apparatus according to claim 4, wherein the weir is movable and the height of the weir can be adjusted.