JP2956488B2 - Die casting apparatus and die casting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die casting apparatus and a die casting method in which molten metal supplied into an injection sleeve is filled by pressing an injection plunger into a mold cavity.

[0002]

2. Description of the Related Art As shown in FIG. 8, for example, a die casting apparatus for manufacturing aluminum parts for automobiles comprises a fixed die 1 and a movable die 2, and a cavity 3 therein.
And an injection device 5 for filling the cavity 3 with a metal (aluminum) molten metal M. The injection device 5 communicates with the cavity 3 via a runner 6 so as to move an injection plunger 9 forward and backward in an injection sleeve 8 having a hot water supply port 7.

[0003] The mold clamping process of the mold 4, the hot water supply process of supplying the molten metal M from the hot water supply port 7 into the injection sleeve 8 by the ladle 10, and the injection plunger 9
Are advanced to press the molten metal M of the injection sleeve 8 to fill the cavity 3 with the injection, and after the metal M in the cavity 3 is solidified, the mold 4 is opened and the product is opened. An extraction step is performed. At this time, before performing the next mold clamping step, a step of spraying and applying a release agent to the inner surface of the cavity 3 and further spraying and applying a tip lubricant T to the inner surface of the injection sleeve 8 is executed. It has become.

[0004]

As described above, in the injection device 5, the tip lubricant T is sprayed on the inner surface of the injection sleeve 8 to smoothly slide the injection plunger 9 (chip). Although it is applied, it is desirable to use an oil-based chip lubricant, an oil-based lubricant containing graphite powder, or the like as the chip lubricant T in order to obtain sufficient lubricity. However, since the oil-based lubricant T is flammable, when the molten metal M is supplied,
There was a problem that a fire F was generated by being ignited by the high heat and rising from the hot water supply port 7. This flame F
When large, it may rise to about 70 cm.

Therefore, in order to prevent the generation of such a flame F, a water-soluble tip lubricant T which is relatively inflammable has been used. However,
Since the water-soluble lubricant T is inferior in lubricity to the oil-based lubricant, abrasion of the injection sleeve 8 and the injection plunger 9 (tip) increases, causing a problem of shortening the service life.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to effectively prevent the generation of a flame by a lubricant while obtaining sufficient lubrication of an injection plunger by the lubricant. It is an object of the present invention to provide a die casting apparatus and a die casting method which can be performed.

[0007]

According to the present invention, there is provided a die casting apparatus, comprising: a mold forming a cavity; an injection sleeve communicating with the cavity via a runner; and an injection plunger moving forward and backward in the injection sleeve. Wherein the molten metal is supplied from the hot water supply port into the injection sleeve, and the molten metal is pressurized by advance of the injection plunger to fill the cavity with the molten metal. Inert gas blowing means for blowing an inert gas from the outside to the hot water supply port during hot water supply, and suction means for sucking the inert gas blown by the inert gas blowing means through the injection sleeve. (The invention of claim 1).

[0008] In this case, the inert gas blowing means is configured to guide an inert gas from a gas supply source to a blowing port body arranged near the hot water supply port by a pipe, and the blowing port body is provided with the inert gas blowing means. It is more preferable that the opening is configured to expand toward the hot water supply port (the invention of claim 2). Further, the suction means includes a suction path provided in the mold, one end of which is connected to the cavity, a suction pump connected to the other end of the suction path, and an opening / closing mechanism for opening and closing the suction path. It can also be configured to include (the invention of claim 3).

Then, the die casting method of the present invention comprises:
A mold closing step of forming a cavity, a hot water supply step of supplying a molten metal from a hot water supply port into an injection sleeve that is connected to the cavity via a runner, and an injection plunger being fed forward through the injection sleeve. And an injection step of filling the cavity with the molten metal that has been performed, wherein the hot water supply portion is blown with an inert gas from the outside during the hot water supply step, and It is characterized in that the inert gas is sucked through the injection sleeve (the invention of claim 4).

[0010] At this time, it is more effective if the inert gas is blown continuously until the injection plunger advances and closes the hot water supply port in the injection step after the hot water supply step is completed. (The invention of claim 5).

[0011]

According to the die casting apparatus of the first aspect of the present invention, when the molten metal is supplied into the injection sleeve, the inert gas is supplied from the outside to the hot water supply port by the inert gas blowing means. The inert gas is sprayed through the injection sleeve by the suction means. As a result, the hot water inlet and the injection sleeve are filled with the inert gas, and the lubricant and the molten metal in the injection sleeve are cut off from the outside air (oxygen).

[0012] Therefore, even if a highly flammable lubricant is present in the injection sleeve and the high heat of the molten metal is received, the lubricant does not ignite, and the injection plunger can be sufficiently lubricated by the lubricant. While obtaining, it is possible to prevent the occurrence of flame due to the lubricant. In addition, since the molten metal can be prevented from coming into contact with oxygen, an effect of preventing oxidation of the molten metal can also be obtained.

[0013] In this case, the inert gas blowing means is configured to guide an inert gas from a gas supply source to a blowing port disposed near the hot water supply port by a pipe, and the inert gas blowing means is provided with a pipe. Is configured so as to expand toward the hot water supply port (the die casting apparatus of claim 2), the entire hot water supply port portion can be covered with the inert gas blown from the blowing port body. And good barrier properties against oxygen.

The suction means may include a suction path provided in the mold, one end of which is communicated with the cavity, a suction pump connected to the other end of the suction path, and an opening and closing mechanism for opening and closing the suction path. And a mechanism (claim 3).
In this case, not only the inside of the injection sleeve but also the inside of the cavity can be filled with the inert gas, and the oxidation of the molten metal in the cavity can be prevented. Further, by closing the suction path by the opening / closing mechanism, it is possible to prevent a problem that the molten metal enters the suction path.

According to the die casting method of the present invention, an inert gas is blown from the outside to the hot water supply port during the hot water supply step, and the blown inert gas is passed through the injection sleeve. Since the suction is performed, the hot water inlet and the injection sleeve are filled with the inert gas, and the lubricant and the molten metal in the injection sleeve are cut off from the outside air (oxygen).

Accordingly, even if a flammable lubricant is present in the injection sleeve and the high heat of the molten metal is received, the lubricant does not ignite, and thus the injection plunger can be sufficiently lubricated by the lubricant. While obtaining, it is possible to prevent the occurrence of flame due to the lubricant. In addition, since the molten metal can be prevented from coming into contact with oxygen, an effect of preventing oxidation of the molten metal can also be obtained.

At this time, the blowing of the inert gas is continued until the injection plunger advances and closes the hot water supply port in the injection step after the hot water supply step is completed. Die casting method), even after the hot water supply in the injection sleeve is completed, it is possible to reliably prevent the molten metal in the injection sleeve from coming into contact with oxygen at the hot water supply port, further improving the antioxidant effect of the molten metal. Can be enhanced.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. First, referring to FIG.
The overall configuration of the die casting apparatus 11 according to the present embodiment will be described. The die casting apparatus 11 is roughly divided into a mold apparatus 12 for performing casting, an injection apparatus 13 for filling the molten metal M, a gas blowing apparatus 14 as an inert gas blowing means, and a gas suction apparatus 15 as a suction means. It is configured.

The mold apparatus 12 includes a mold 19 including a fixed mold 17 fixed to a platen 16 and a movable mold 18 movable toward and away from the fixed mold 17. The apparatus is provided with a mold driving device (not shown) which moves in the direction of contact and separation with the fixed mold 17 to clamp and open the mold. In the mold clamping state, the cavity 2 corresponding to the shape of the cast product is formed in the mold 19.
0 is formed.

In the mold 19, the cavity 2 is provided.
An overflow portion 21 for releasing excess molten metal M is provided through a flat overflow gate, which is located at an upper portion in FIG. Further, although not shown in detail, the mold 19 is provided with a product take-out mechanism including an extrusion pin 22 and the like. Note that the mold 19 is provided with an unillustrated gas vent. Further, as described later, a release agent is sprayed and applied to the inner surface of the cavity 20.

On the other hand, the injection device 13 is shown in FIGS.
As shown in the figure, the injection sleeve 23 extends continuously from the lower part to the right in the drawing of the mold 19 (fixed die 18), and the injection plunger 2 moves forward and backward in the injection sleeve 23.
4 and a drive unit (not shown) for reciprocating the injection plunger 24. The distal end (the left end in the figure) of the injection sleeve 23 communicates with the cavity 20 via a runner 25. The tip 24a of the tip of the injection plunger 24 slides on the inner surface of the injection sleeve 23. In order to smoothly perform the sliding at this time, the inner surface of the injection sleeve 23 is lubricated. A good oil-based chip lubricant T is applied by spraying. In this embodiment, the moving speed of the injection plunger 24 is variable.

A water inlet 26 is provided on the upper surface of the injection sleeve 23. Further, although not shown in detail, a supply mechanism for supplying a molten metal (for example, molten aluminum) M from the hot water supply port 26 into the injection sleeve 23 is provided. The supply mechanism includes a furnace for holding the molten metal M, a ladle 27 for pouring the molten metal M from the hot water supply port 26, and the like.

As will be described later in detail, the mold clamping step of the mold 19, the hot water supply step of supplying the molten metal M from the hot water supply port 26 into the injection sleeve 23 by the ladle 27, and the injection plunger 24 are shown in FIG. An injection step of moving forward to the left to pressurize the metal melt M in the injection sleeve 23 to fill the cavity 20 is sequentially performed. After that, the metal M in the cavity 20 solidifies, Is opened to take out the product. At this time, before performing the next mold clamping step, a step of spraying and applying a release agent to the inner surface of the cavity 20 and further spraying and applying the tip lubricant T to the inner surface of the injection sleeve 23 is executed. It has become.

Now, the gas blowing device 14 and the gas suction device 15 will be described. First, the gas blowing device 14
An inert gas such as nitrogen gas is blown from the outside to the hot water supply port 26 portion. A nitrogen gas cylinder 28 serving as a gas supply source and a blowing port body 29 arranged in the vicinity of the hot water supply port 26 are connected by piping. 30.

At this time, as shown in FIGS. 2 and 3, the blowing port body 29 is made of, for example, a thin metal plate or plastic, and expands from the back side to the front side. It has a thin box shape with a horizontally long opening 29a corresponding to the mouth 26. The blowing port body 29 is located just above the hot water supply port 26 of the injection sleeve 23 at the back and is attached to the platen 16 by a mounting stay 31 and a mounting rod 32. Further, the pipe 30 is connected to a deep portion of the blowing port body 29 by a connector 33.

Then, as shown in FIG.
Is provided with a regulator 34 for adjusting pressure and an electromagnetic valve 35 for opening and closing the pipe 30.
Is provided. When the electromagnetic valve 35 is opened, the nitrogen gas from the nitrogen gas cylinder 28 is blown toward the front side, that is, toward the hot water supply port 26 from the opening 29 a of the blowing port body 29 at a pressure adjusted by the regulator 34. It can be attached. At this time,
The opening 29a of the blowing port body 29 has a horizontally elongated flat shape corresponding to the width of the hot water supply port 26, so that the upper surface of the hot water supply port 26 is covered with a gas curtain of nitrogen gas.

On the other hand, the gas suction device 15 is for sucking gas (air or nitrogen gas) in the cavity 20 and the injection sleeve 23 communicating with the cavity 20. ), A suction pump 37 serving as a suction source connected to the base end side of the suction path 36, a vacuum gauge 38 for detecting the pressure in the suction path 36, and an opening and closing for opening and closing the suction path 36. Mechanism 3
9 and so on. The suction path 36 has a base end opening at the outer surface of the mold 19 and a tip end opening at the overflow section 21, thereby communicating with the upper portion of the cavity 20 via the overflow section 21. Have been. Then, the base end side of the suction path 36 is connected to the suction pump 37 via a pipe 40 outside the mold 19.

The opening / closing mechanism 39 comprises a cut-off pin 42 which is reciprocally moved in the left-right direction by a hydraulic cylinder 41 and an electromagnetic valve 43 for turning the hydraulic cylinder 41 on and off. As a result, in the forward state (normal state) of the cutoff pin 42, the distal end of the cutoff pin 42 blocks the distal end opening of the suction path 36, and the hydraulic cylinder 41 is operated by the electromagnetic valve 43. Then, as shown in the figure, the cut-off pin 4
2 retracts (to the left in the figure) to open the suction path 36.

Next, a casting method in the die casting apparatus 11 configured as described above will be described with reference to FIGS.
Also described with reference to FIG. FIG. 4 shows the flow of the casting process in order. That is, when the mold opening process (P1) of the mold 19 is performed and the previous casting product removal process (P2) is completed,
Next, a release agent spraying step (P3) of spraying and applying a release agent to the inner surface of the cavity 20 of the mold 19, and a chip lubricant spraying step of spraying and applying the chip lubricant T to the inner surface of the injection sleeve 23 ( P4) is executed. At this time, in the present embodiment, an oil-based lubricant having excellent lubricity but relatively flammable properties is used as the tip lubricant T.

Subsequently, the mold clamping step (P5) of the mold 19 is executed, and subsequently the hot water supply step (P6) is executed. At this time, in the steps up to the mold clamping step (P5), the electromagnetic valve 35 is closed, no nitrogen gas is blown from the blowing port body 29, and the cutoff pin 42 is in the forward state. The suction path 36 is closed. The injection plunger 24 is also retracted, and the hot water supply port 26 is open.

In the hot water supply step (P6), as described above, the molten metal M is supplied by the ladle 27 to the hot water supply port 26.
Is injected into the injection sleeve 23 at the same time. At the start of the hot water supply process, the gas blowing device 14 and the gas suction device 15 are operated to execute the nitrogen gas blowing and suctioning process (P7). . The spraying of nitrogen gas
The electromagnetic valve 35 provided in the pipe 30 is opened, and the nitrogen gas from the nitrogen gas cylinder 28 is blown at a required pressure.
It is performed by leading to. Also, the suction of nitrogen gas
This is performed by retracting the cut-off pin 42 by the hydraulic cylinder 41 to open the suction path 36 and driving the suction pump 37.

Thus, while the supply of the molten metal M into the injection sleeve 23 is being performed, the opening 29
a, the nitrogen gas is sprayed toward the upper surface of the hot water supply port 26, and the nitrogen gas is injected into the injection sleeve 2.
3 and is further suctioned through the cavity 20 of the mold 19. In the initial stage of suction, air remaining in the cavity 20 and the injection sleeve 23 is sucked and gradually replaced by nitrogen gas. Is filled with nitrogen gas. At this time, since the blowing port body 29 has an expanded shape, the entire hot water supply port 26 can be covered with a curtain of nitrogen gas, and the oxygen barrier properties are extremely good.

Here, since the relatively flammable tip lubricant T on the inner surface of the injection sleeve 23 receives the high heat of the molten metal M, if oxygen (air) exists around the tip lubricant T, it ignites and the flame is generated. There is a situation that causes. However, since the steps of spraying and sucking nitrogen gas (P7) are performed simultaneously, the tip lubricant T and the molten metal M in the injection sleeve 23 are shut off from the outside air (oxygen) by the nitrogen gas. Therefore, the hot water supply step (P6) is completed without the tip lubricant T igniting. In addition, the metal melt M is prevented from being oxidized by contact with oxygen.

When the hot water supply step is completed, the injection plunger 2
4 is advanced to pressurize the molten metal M to fill the cavity 20 through the runner 25 (P8). At this time, in this embodiment, the injection plunger 24 moves forward at a low speed until the tip 24a closes the hot water supply port 26, and moves forward at a high speed from there. Has become. Then, the step of spraying and sucking the nitrogen gas (P7)
As shown in the "basic pattern" in FIG. 5, the tip 24a of the injection plunger 24 is continuously carried out throughout the hot water supply step (P6), and even when the hot water supply step ends and the injection step (P8) starts. Until the hot water supply port 26 is closed.

When the injection plunger 24 closes the hot water supply port 26 and there is no longer a risk of external air entering the injection sleeve 23, the electromagnetic valve 35 is closed, and the cut-off pin 42 is advanced to move the suction path 36. By shutting down and stopping the suction pump 37, the process of spraying and sucking nitrogen gas (P7) is completed. As described above, by continuing the process of blowing and sucking nitrogen gas until the beginning of the injection process, the molten metal M in the injection sleeve 23 comes into contact with oxygen at the hot water supply port 26 even after the hot water supply is completed. Can be reliably prevented, and the effect of preventing oxidation of the molten metal can be further enhanced. Further, at this time, since the inside of the cavity 20 has also been replaced with nitrogen gas, the molten metal M
Can also be prevented from being oxidized.

When the molten metal M is filled into the cavity 20 under pressure, the injection process is completed. At this time, if the molten metal M is excessively charged, the excess escapes into the overflow section 21. At this time, since the distal end of the suction path 36 is already closed by the cutoff pin 42, This prevents the molten metal M from entering the suction path 36 before it occurs. Thereafter, a solidification step (P9) for solidifying the molten metal M pressurized and filled in the cavity 20 is performed. When the solidification is completed, the steps from the mold opening (P1) of the mold 19 are repeated again.

As described above, according to the present embodiment, the gas blowing device 14 and the gas suction device 15 are operated at the beginning of the hot water supply step and the injection step, so that the hot water supply port 2
The six portions and the injection sleeve 23 are filled with nitrogen gas, and the tip lubricant T and the molten metal M in the injection sleeve 23 are cut off from the outside air (oxygen), so that the tip lubricant T No more ignition. Therefore, unlike the conventional one in which the water-soluble tip lubricant T is used at the expense of lubrication to prevent the generation of the flame F, the tip lubricant T having sufficiently good lubricity is used. Thus, it is possible to effectively prevent the generation of flame due to the tip lubricant T while obtaining a long life of the injection sleeve 23 and the injection plunger 24. In addition, since the molten metal M can be prevented from coming into contact with oxygen, a secondary effect of preventing oxidation of the molten metal M can also be obtained.

In this case, particularly in this embodiment, the spray port 2
9 is formed so as to expand toward the hot water supply port 26, so that the entire hot water supply port 26 can be covered with a gas curtain of nitrogen gas, so that the barrier property against oxygen can be further improved. In the present embodiment, not only the inside of the injection sleeve 23 but also the inside of the cavity 20 is filled with the nitrogen gas, so that the oxidation of the molten metal M in the cavity 20 can be prevented, and furthermore, the cutting is performed. The off pin 42 can reliably prevent a problem that the molten metal M enters the suction path 36.

Further, in the present embodiment, in particular, the spraying and sucking of the nitrogen gas is performed not only during the hot water supply process, but also until the beginning of the subsequent injection process (when the injection plunger 24 is connected to the hot water supply port 26).
) Until the hot water is completely supplied into the injection sleeve 23, so that the molten metal M in the injection sleeve 23 is reliably prevented from coming into contact with oxygen at the hot water supply port 26. Thus, the effect of preventing the tip lubricant T from being ignited and the effect of preventing the molten metal M from being oxidized can be further enhanced.

Conventionally, in this type of die casting apparatus, in order to prevent oxidation of the molten metal, a method of replacing air in the cavity with an inert gas and then filling the molten metal into the cavity has been considered. (Japanese Patent Laid-Open No. 5-2
No. 93589). However, in this apparatus, since the hot water supply port portion is not covered with the nitrogen gas film at the time of hot water supply on the injection device side, the effect of preventing generation of flame cannot be obtained. On the other hand, in the present embodiment, since the nitrogen gas is always blown to the hot water supply port 26 during the hot water supply step, the tip lubricant T can be reliably prevented from coming into contact with oxygen. Thus, the generation of flame can be effectively prevented.

In the above embodiment, the blowing and sucking of the nitrogen gas is started at the same time as the start of the hot water supply step and is ended at the beginning of the injection step (basic pattern in FIG. 5). As shown in (1), other patterns (deformation patterns A to C) are also possible. In the modification pattern A, the blowing and inhalation of the nitrogen gas is started at the same time as the start of the hot water supply process and is ended at the same time as the completion, and in the modification pattern B, only the blowing of the nitrogen gas is continued until the beginning of the injection process. In the deformation pattern C, the blowing and inhaling of the nitrogen gas is started in the middle of the hot water supply process. Various modifications other than these illustrated patterns are possible.

FIG. 6 shows another embodiment of the present invention. This embodiment differs from the above-described embodiment in the structure of a gas suction device 51 serving as suction means. That is, in the gas suction device 51 of the present embodiment, the tip of the suction pipe 52 is located at a position on the front side of the hot water supply port 26 of the injection sleeve 23 and is open. An electromagnetic valve 53 and a suction pump 54 are connected to the ends.

In this case, the hot water supply 2
The nitrogen gas blown toward 6 is injected into the injection sleeve 23.
The suction pipe 52 is sucked through the inside. Even in such a configuration, the intended purpose of preventing the generation of flame by the tip lubricant T at the time of hot water supply can be achieved. Further, the opening / closing mechanism 39 such as the cutoff pin 42 as in the above embodiment is not required, and the configuration is simplified. Thus, the position where the inert gas is sucked can be variously modified.

Various modifications are also possible in the gas blowing device. For example, in place of the above-mentioned spray port body 29, FIG.
A manifold type blowing port 61 as shown in FIG. The blowing port body 61 has, for example, four blowing cylinders 62 arranged in the lateral direction corresponding to the width of the hot water supply port 26 on the front surface of the main portion 61a to which the pipe 30 is connected. Also in this configuration, the entire hot water supply port 26 can be covered with a nitrogen gas curtain.

In addition, for example, carbon dioxide, neon, argon gas or the like can be used as the inert gas.
The present invention can be practiced with appropriate modifications without departing from the gist, for example, various metals such as an aluminum alloy and a zinc alloy can be used.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a longitudinal sectional front view showing an entire configuration of a die casting apparatus.

FIG. 2 is a top view showing a hot water supply port and a spray port.

FIG. 3 is a front view showing a hot water supply port and a spray port.

FIG. 4 is a diagram showing a process of die casting.

FIG. 5 is a diagram showing a pattern of blowing and suctioning an inert gas to hot water.

FIG. 6 is a diagram corresponding to FIG. 1, showing another embodiment of the present invention.

FIG. 7 is a perspective view of a spray port showing another different embodiment.

FIG. 8 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

In the drawings, 11 is a die casting apparatus, 12 is a mold apparatus,
13 is an injection device, 14 is a gas blowing device (inert gas blowing device), 15 is a gas suction device (suction device), 19 is a mold, 20 is a cavity, 21 is an overflow portion, 23
Is an injection sleeve, 24 is an injection plunger, 25 is a runner, 26 is a hot water supply port, 27 is a ladle, 28 is a nitrogen gas cylinder (gas supply source), 29 and 51 are blowing ports, 36 is a suction path, and 37 and 54 are suction. A pump, 39 is an opening / closing mechanism (opening / closing means), 42 is a cut-off pin, M is a molten metal, and T is a tip lubricant.

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Claims (5)

(57) [Claims] 1. A mold for forming a cavity, an injection sleeve communicated with the cavity via a runner,
An injection plunger which moves forward and backward in the injection sleeve, supplies a molten metal into the injection sleeve from a hot water supply port, and fills the cavity by pressurizing the molten metal by advancing the injection plunger. An inert gas blowing means for blowing an inert gas from the outside to the hot water supply port when hot water is supplied into the injection sleeve; and an inert gas blown by the inert gas blowing means. A die casting apparatus, further comprising: suction means for suctioning through an injection sleeve. 2. The inert gas blowing means is configured to guide an inert gas from a gas supply source to a blowing port disposed near the hot water supply port by a pipe.
The die casting apparatus according to claim 1, wherein the blowing port body is formed to expand toward the hot water supply port. 3. The suction means includes: a suction path provided in the mold, one end of which is communicated with a cavity; a suction pump connected to the other end of the suction path; The die casting apparatus according to claim 1, further comprising a mechanism. 4. A mold-clamping step for forming a cavity, a hot-water supply step of supplying a molten metal from a hot-water supply port to an injection sleeve communicated with the cavity via a runner, and an injection plunger in the injection sleeve. And an injection step of filling the cavity with the supplied molten metal by moving the molten metal into the cavity in a die-casting method. A method for die-casting, wherein the blown inert gas is sucked through the injection sleeve while being blown. 5. The spraying of the inert gas is performed until the injection plunger advances and closes the hot water supply port in the injection step after the hot water supply step is completed. Die casting method.