JP3967573B2 - Degassing device for mold and method of using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for extracting gas from a cavity in mold casting and a method for using the apparatus.
[0002]
[Prior art]
Japanese Patent Application No. 2000-337686 discloses a gas venting device for this type of mold. As shown in FIG. 8, a passage 102 communicating with the cavity is formed between the fixed mold 100 and the movable mold 101, a closing valve 103 is arranged on the outlet side of the passage, and a lever 104 for opening and closing the closing valve is provided. A pressure receiving pin 105 is provided so as to be able to swing, and is slidably provided on the inlet side of the passage so as to push the lever when the molten metal pressure in the passage rises. Further, an open spring 106 that constantly presses the lever is provided.
[0003]
However, this is because the valve body 107 of the closing valve is pushed out by the force of the opening spring when the mold is opened, so that a large spring load is used for the opening spring. Therefore, due to the load, it was difficult to push the valve body with fingers during maintenance. As a result, it was troublesome to check the opening / closing state of the closing valve, that is, to check whether the valve body moves normally against the opening spring. In the above-described closing valve, the distal end surface of the valve body, that is, the molten metal contact surface is formed to be a smooth surface so that mold release resistance cannot be obtained. It was necessary to extrude into.
[0004]
[Problems to be solved by the invention]
The problem to be solved by the invention of claim 1 developed in view of the above circumstances is to enable the closing valve to be opened and closed with a light force during maintenance, regardless of whether or not the valve main body has a release resistance.
[0005]
Further, the problem to be solved by the invention of claim 2 is to enable the closing valve to be opened with a light force when the mold is opened even when there is no mold release resistance.
[0006]
By the way, some closing valves, such as poppet valves, are kept in close contact with the valve seat, but the above-described closing valve is provided so that the tip of the valve body can be retracted into the bush 108, and the tip is By immersing in the bush, the passage is closed so that the molten metal is not discharged. For this reason, the dimension of the clearance between the bush and the tip of the valve body cannot be designed wider than a certain value. Then, when the heat of the molten metal is received, a phenomenon occurs in which the valve body and the bush are thermally expanded and the clearance is lost. Also, when the mold is opened, the force of the opening spring is indirectly applied from the lever to the valve body, but the clearance is lost due to the thermal expansion of the valve body and the bush, so the closing valve is closed. Is maintained. Then, after a certain period of time, for example, a few seconds, immediately after the mold is opened, the heat escapes and the clearance is formed again, the valve body is pushed out by the force of the opening spring, and the closing valve is opened.
[0007]
However, as described above, the force of the opening spring is not applied to the valve body after the clearance is sufficiently opened, but is applied when there is no clearance, so the clearance when the valve body starts to move in the opening direction is It can be said that it is narrower than the ideal interval for smooth movement. Therefore, since the valve body is pushed in and moved, the wear is severe and the durability is shortened.
[0008]
In addition, the clearance between the tip of the valve body and the cylinder cannot be increased beyond a certain value even if the diameter of the valve body is increased for the reasons described above, so that the thermal expansion has occurred as the diameter of the valve body increases. Rather than saying that there is no clearance between the valve body and the cylinder sometimes, the valve body is pressed firmly. For this reason, the time until the clearance is made becomes long, and the force of the opening spring takes a long time, and the durability is further adversely affected.
[0009]
The problem to be solved by the inventions of claims 3 and 4 is that, in addition to the problem to be solved by the invention of claim 2, the timing at which the closing valve is opened can be waited until the clearance is sufficiently formed.
[0010]
[Means for Solving the Problems]
The solution of the invention according to claim 1 is provided with an open cylinder that opens the closing valve in a fixed mold, and the fixed mold is attached to the main block incorporating the closing valve on the opposite side of the mating surface with the movable mold, The closing cover of the closing valve is equipped with an auxiliary block with a built-in open cylinder . The open cylinder is a single-action air cylinder that moves backward with a spring, and an open cylinder chamber is formed in the auxiliary block in the direction of extension of the valve body. In the state where the open cylinder chamber has an open piston, the tip of the piston rod penetrates the cover lid and enters and exits the bush, and the piston rod tip protrudes out of the bush due to the restoring force of the spring. If the tip of the rod is separated and the tip of the piston rod enters the bush by compressed air, the piston rod It is intended to push the top of the valve body at the end.
[0011]
Moreover, as a premise of the gas venting device for the mold, a closed valve is provided with a fixed mold and a movable mold, a passage leading to the cavity is formed by the fixed mold and the movable mold, and the valve body slides in the cylindrical bush. Is provided on the outlet side of the passage, and a pressure receiving pin is slidably provided on the inlet side of the passage, and an intermediate portion of the lever supported to be swingable is provided so that it can be pushed in by the pressure receiving pin. Is engaged with the head of the valve main body, and the pushing movement of the pressure receiving pin due to the rise of the molten metal pressure in the passage is changed to the forward movement of the valve main body via the lever to close the closing valve.
[0012]
The fixed mold and the movable mold can be mounted not only when the fixed mold is mounted on the fixed mold and the movable mold is mounted on the movable mold, but also when the fixed mold is mounted on the movable mold and the movable mold is mounted on the fixed mold. is there. The passage is not limited to a single flow path leading to the cavity, but may be a plurality of passages. Therefore, the entrance side of the passage here means a position before the molten metal reaches the closing valve.
[0013]
As the gas venting device for a mold, a valve body provided with unevenness for releasing resistance may be used on the tip surface of the valve main body that contacts the molten metal. In this case, the open cylinder is activated at the beginning of casting. Also, in the gas venting device for the mold, the tip surface that contacts the molten metal of the valve body is formed to be a smooth surface, and the degree of smoothness is such that the bubble body is separated by the moment of removing the surplus member when the mold is opened, and the closed state is maintained. You may use the thing of the grade maintained. In the latter case, the open cylinder is operated even when the mold is opened.
[0014]
Furthermore, the closing valve of the gas venting device for the mold is provided so that the tip of the valve body can be protruded and retracted in the bush, and a clearance for protrusion and removal is provided between the tip of the valve body and the bush. When the tip of the valve body protrudes from the bush , the passage opens, and when the tip of the valve body is immersed in the bush due to the pressing movement of the pressure receiving pin, there is a clearance between the tip of the valve body and the bush. However, after that, the bush and the tip of the valve main body are thermally expanded by the heat of the molten metal that has reached the closing valve, and the clearance is lost and the passage becomes inaccessible in a close state .
[0015]
The method of using the degassing apparatus for a mold according to the present invention is such that the degassing apparatus for a mold includes a fixed mold and a movable mold, a passage leading to the cavity is formed by the fixed mold and the movable mold, and a cylindrical bush There is a closing valve on the outlet side of the passage, and a pressure receiving pin is slidably provided on the inlet side of the passage. In addition to being provided so that it can be pushed in, the tip of the lever is engaged with the head of the valve body, and the push-in movement of the pressure receiving pin due to the rise in the molten metal pressure in the passage is changed to the forward movement of the valve body via the lever to An open cylinder that closes and opens the closed valve is provided in a fixed mold, and the open cylinder is provided so that the top of the valve body can be pushed in directly, and the tip surface of the valve body that contacts the molten metal is formed into a smooth surface. The degree of mold opening The bubble main body is separated and maintained in the closed state by the moment of removing the surplus member, and the closing valve is provided in the bush so that the front end of the valve main body can be projected and retracted, and between the front end of the valve main body and the bush. Has a clearance for intrusion, the passage opens when the tip of the valve body protrudes, and the passage becomes inaccessible when the tip of the valve body is recessed. Is attached to the fixed mold and movable mold, the molten metal is filled into the cavity, the molten metal overflowing from the cavity flows into the passage of the degassing device for the mold, pushes the pressure receiving pin, and indirectly connects the valve body through the lever. The closed valve is moved forward to close the closed valve, the bush that is thermally expanded by the heat of the molten metal and the tip of the valve body are in close contact, and after the molten metal has solidified, the mold is opened and the surplus member is taken out. Wait until the clearance between the tip portion of the bush and the valve body is formed by a by cooling teeth, the open cylinder is actuated, characterized in that opening the closing valve is pushed directly to the valve body. Further, the closing valve of the gas venting device for the mold used in this method is provided so that the tip of the valve body can be moved in and out in the bush, and a clearance for protrusion and removal is provided between the tip of the valve body and the bush, It is assumed that the passage is opened with the tip of the valve body protruding, and the passage is blocked with the tip of the valve body immersed.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 4 shows an outline of the mold, where 1 is a fixed mold, 2 is a movable mold, 3 is a cavity fixed mold, 4 is a cavity movable mold, and 5 is a cavity. The molten metal injected into the injection sleeve 6 is press-fitted into the cavity 5 by the injection piston 7, the passage 8 provided continuously to the cavity 5 is extended into the gas venting device 9, and the suction device ( (Not shown) are continuous.
[0017]
As shown in FIG. 1, the gas venting device 9 includes a fixed mold 10 attached to the fixed mold 1 and a movable mold 11 attached to the movable mold 2, and a passage 8 is formed by the fixed mold 10 and the movable mold 11. The pressure receiving pin 12 is slidably provided on the inlet side of the passage 8, the closing valve 13 is provided on the outlet side of the passage 8, and the lever 14 that changes the forward movement of the pressure receiving pin 12 to the closing movement of the closing valve 13 can be swung. And an opening cylinder 15 that directly presses and opens the closing valve 13, and an auxiliary closing cylinder 16 that presses the lever 14 and indirectly closes the closing valve 13.
[0018]
As shown in FIG. 5, the passage 8 has one flow path 17 leading to the cavity 5, one of which leads to the pressure receiving pin 12 on the inlet side, and then the bifurcated flow paths 18 and 18 on the outlet side. As shown in FIG. 6, there are one that communicates with the closing valve 13, and there are a plurality of flow paths 17 that communicate with the cavity 5, one of which communicates with the pressure receiving pin 12, and the other that communicates with the closing valve 13. In either case, before the molten metal reaches the closing valve 13, the pressure receiving pin 12 is pushed by the pressure of the molten metal, and the closing valve 13 is closed. Further, when the passage 8 is divided into a part before reaching the closing valve 13 and a part after reaching, the passage 8 is formed on the mating surface of the fixed mold 10 and the movable mold 11 before reaching, and on the other hand, after reaching, from the mating surface. The fixed mold 10 is bent in an L shape. The movable mold 11 is a block having a flat mating surface.
[0019]
In the fixed mold 10, a cover 20 is attached to the main block 19 on the opposite side of the mating surface, and main components such as a closing valve 13 are built in. An auxiliary block 21 with a built-in open cylinder 15 is provided in the extending direction of the closing valve 13. It is fixed to.
[0020]
The main block 19 includes a closing valve 13 from the outlet side of the passage 8 toward the cover lid 20, extends a pin housing chamber 22 toward the cover lid 20 on the inlet side of the passage 8, and receives a pressure receiving pin in the pin housing chamber 22. 12 is slidably accommodated. Further, a lever chamber 23 communicating with the pin accommodating chamber 22 and the head of the closing valve 13 is formed on the cover 20 side of the main block 19, and the lever 14 is swingably provided in the lever chamber 23. Is provided so that it can be pushed by the pressure receiving pin 12, the tip end of the lever 14 is engaged with the head of the closing valve 13 so as to be opened and closed, and an auxiliary closing cylinder 16 is provided between the pressure receiving pin 12 and the closing valve 13.
[0021]
In the closing valve 13, the valve housing chamber 24 is formed from the outlet side of the passage 8 toward the cover 20, and a part of the passage 8 is used as a part of the valve housing chamber 24. The valve housing chamber 24 is provided with a cylindrical bush 25, and a valve main body 26 is slidably provided in the bush 25, and a distal end portion of the valve main body 26 is provided in the bush 25 so as to be able to protrude and retract. .
[0022]
The bush 25 is formed with a passage hole 27 on the front side and a hole 28 through which the lever 14 passes on the head side. The valve body 26 has a cylindrical shape, a lateral hole 29 into which the lever 14 is inserted in the head, a thin tip and a gap for the passage between the bush 25 and a thick tip. This prevents the melt from flowing out.
[0023]
The bush 25 and the valve body 26 are thermally expanded upon receiving the heat of the molten metal. Both materials have thermal expansion coefficients of 11.56 × 10 ⁻⁶ / mm ° C., and the valve body 26 has a diameter of 10 mm. When the diameter of 29 mm is used, the clearance between the tip of the valve body 26 and the bush 25 is set to 15 microns.
[0024]
When the distal end of the valve body 26 and the bush 25 are in contact with the molten metal and thermally expand, the clearance described above disappears and comes into close contact. If the sliding is performed in close contact, the durability is lowered. Therefore, the sliding is kept on standby until a clearance necessary for smooth sliding is formed. The required clearance dimension is 2 microns or more. When the molded product is taken out from the cavity 5, the surplus member 30 in the passage 8 is also taken out at the same time, and the tip surface of the valve body 26 and the tip surface of the bush 25 are cooled by contact with air, but the clearance becomes 2 microns after taking out the molded product. It took 1 second until the diameter was 10 mm. The time until the necessary clearance is formed becomes longer as the diameter of the valve body 26 becomes thicker, and it takes 5 seconds when the diameter is 29 mm.
[0025]
Further, in the experiment, when the temperature of the tip end portion of the valve body 26 was higher than the tip end portion of the bush 25 by 45 ° C. or more, the tip end portion of the valve body 26 did not enter the bush 25. Therefore, in order to allow the tip of the valve body 26 to smoothly appear and disappear in the bush 25, the temperature of the tip of the valve body 26 needs to be in a condition of 0 ° C. or more and less than 45 ° C. than the temperature of the bush 25.
[0026]
The pressure receiving pin 12 includes a support collar 31 on the head side and a protrusion 32 that contacts the lever 14. In addition, unevenness is provided on the tip surface (melt contact surface) so as to obtain mold release resistance.
[0027]
The swing mechanism of the lever 14 is configured such that a shaft support lid 33 is fixed to the inner surface of the cover lid 21 so that a part of the lever chamber 23 is formed slightly wider than the support end of the lever 14 and the slightly wider part thereof is formed. The support end of the lever 14 is inserted.
[0028]
The auxiliary closing cylinder 16 is operated at the beginning of casting. That is, at the beginning of casting, the molten metal is filled into the cavity 5 at a lower speed than during normal operation, so that the pressure receiving pin 12 is difficult to move. Therefore, before the molten metal reaches the closing valve 13, the auxiliary closing cylinder 16 is operated to operate the lever. 14 is pushed in and the closing valve 13 is closed. Specifically, a closed cylinder chamber 34 is formed between the pin accommodating chamber 22 and the valve accommodating chamber 24 so as to communicate with the lever chamber 23, and the closed piston 35 is reciprocated in the state where the closed piston 35 is in contact with the lever 14. It is provided so as to be movable, and communicates with the outside through the communication path 36 from the closed cylinder chamber 34, and the closed piston 35 is reciprocated by a pneumatic circuit (not shown) using an air compressor.
[0029]
The open cylinder 15 can be operated not only when the mold is opened but also at the beginning of casting. The open cylinder 15 is a single-acting air cylinder that is moved back by a spring (not shown). An open cylinder chamber 37 is provided in the auxiliary block 21, and the valve body 26 is extended. The open cylinder chamber 37 is provided with an open piston 38, a spring is passed through the piston rod 39, a through hole 40 through which the tip of the piston rod 39 enters and exits into the bush 25 is opened in the cover lid 20, and the piston rod 39 The top of the valve body 26 is provided so that it can be pushed in at the tip, and the communication path 41 is provided in the open cylinder chamber 37 so as to communicate with the outside, and is operated by a pneumatic circuit using an air compressor.
[0030]
The timing for operating the open cylinder 15 is controlled by a control device (not shown). Specifically, after the mold is opened, measurement is started from the time when the molded product is taken out from the cavity, and waiting is performed until the clearance of 2 microns is opened. Then, the valve body 26 is pushed in and moved backward to open the closing valve 13.
[0031]
The above-described mold gas venting device 9 is used in the following procedure. First, the mold degassing device 9 is attached to the fixed mold 1 and the movable mold 2 and then clamped as shown in FIG. 2 to fill the cavity 5 with molten metal. The molten metal overflowing from the cavity 5 flows into the passage 8 of the degassing device 9 for the mold, pressurizes the molten metal before reaching the closing valve 13, pushes the pressure receiving pin 12, and moves the valve body 26 through the lever 14. As shown in FIG. 3, the distal end portion of the valve body 26 is immersed in the bush 25 to close the closing valve 13. When this is closed, there is a clearance between the front end of the valve body 26 and the bush 25, but then the bush 25 and the front end of the valve main body 26 are thermally expanded by the heat of the molten metal reaching the closing valve 13, and the clearance is cleared. Close and close. Then, after the molten metal in the passage 8 is solidified to form the surplus member 30, the mold is opened and the surplus member 30 is taken out. However, since the distal end surface of the valve body 26 is formed as a smooth surface, the surplus force is removed by the removed momentum. The valve body 26 is separated from the member 30, and the valve body 26 is stopped at the forwardly moved position. Further, since the pressure receiving pin 12 is provided with unevenness for releasing resistance, the pressure receiving pin 12 moves backward with the removed force. Thereafter, since the clearance between the bush 25 and the tip of the valve body 26 is formed by heat radiation, it waits until the dimension required for smooth sliding is reached, and then the open cylinder 15 is moved as shown in FIG. The valve body 26 is actuated to directly push the valve body 26 back to open the closing valve 13.
[0032]
FIG. 7 shows another example of the degassing device 9 for molds, which is the same as the previous example except that a double-acting cylinder that reciprocates with air is used for the open cylinder 15.
[0033]
The present invention is not limited to the above embodiment. For example, the tip surface of the pressure receiving pin 12 may be formed as a smooth surface. In this case, even if the surplus member 30 is taken out when the mold is opened, the pressure receiving pin 12 does not move backward, so that the opening cylinder 15 needs to have a force enough to push not only the valve body 26 but also the pressure receiving pin 12 at the same time. Become. Further, in the fixed mold 10, the cover 20 and the auxiliary block 21 are separately formed in the drawing, and the auxiliary block 21 is fixed to the cover 20. However, the cover 20 and the auxiliary block 21 may be integrally formed. .
[0034]
【The invention's effect】
According to the first aspect of the present invention, since the open cylinder directly pushes the top of the valve body, the push-in part is the place farthest from the fulcrum of the lever, and the valve body can be moved with a weak force. Further, if the opening cylinder is not operated, no force in the opening direction is applied to the valve body. Therefore, during maintenance, the valve body can be directly pushed with a finger to confirm the movement.
[0035]
In the invention of claim 2, since the tip surface of the valve body is a smooth surface, the valve body remains closed even if the surplus member is taken out. As a result, the opening cylinder is operated when the mold is opened. The closing valve can be opened.
[0036]
According to the third and fourth aspects of the present invention, the valve body whose tip end part appears and disappears in the bush is used as the closing valve. Therefore, when there is no clearance for the appearance due to the heat of the molten metal, the open cylinder is not operated. In addition, if the release cylinder is operated after the heat is released and the clearance is sufficiently formed, wear between the bush and the tip of the valve body can be suppressed, and durability can be improved.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a degassing apparatus for a mold according to the present invention, and shows a state in which an open cylinder is operated after a mold is opened.
FIG. 2 is a cross-sectional view showing a state before the molten metal is press-fitted in the mold gas venting device.
FIG. 3 is a cross-sectional view showing a state in which the closing valve of the mold degassing apparatus is closed with molten metal.
FIG. 4 is a cross-sectional view showing a state where a mold gas venting device is attached.
FIG. 5 is a drawing showing a passage of a degassing device for a mold.
FIG. 6 is a view showing a passage of another mold degassing apparatus.
FIG. 7 is a cross-sectional view showing another example of a gas venting apparatus for a mold.
FIG. 8 is a cross-sectional view showing a conventional mold gas venting device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Fixed mold 2 Movable mold 5 Cavity 8 Passage 9 Mold degassing apparatus 10 Fixed mold 11 Movable mold 12 Pressure receiving pin 13 Closing valve 14 Lever 15 Opening cylinder 25 Bush 26 Valve body 30 Surplus member

Claims (4)

A fixed mold (10) and a movable mold (11) are provided, and a passage (8) leading to the cavity (5) is formed by the fixed mold (10) and the movable mold (11), and inside the cylindrical bush (25). The valve body (26) slides on the outlet side of the passage (8) and the pressure receiving pin (12) is slidably provided on the inlet side of the passage (8). An intermediate length of the lever (14) supported so as to be able to be pushed in by the pressure receiving pin (12) is provided, and the tip end of the lever (14) is engaged with the head of the valve body (26), and the passage (8 In the degassing device for a mold, which closes the closing valve (13) by changing the pushing motion of the pressure receiving pin (12) due to the rise of the molten metal pressure into the forward movement of the valve body (26) via the lever (14),
An open cylinder (15) for opening the closing valve (13) is provided in the stationary mold (10),
The fixed mold (10) has a cover (20) attached to the main block (19) containing the closing valve (13) on the opposite side of the mating surface with the movable mold (11), and the closing direction of the closing valve (13). The side cover (20) is provided with an auxiliary block (21) containing an open cylinder (15).
The open cylinder (15) is a single-acting air cylinder that moves backward with a spring. An open cylinder chamber (37) is formed in the auxiliary block (21) in the direction of extension of the valve body (26), and is opened in the open cylinder chamber (37). A piston (38) is provided, the tip of the piston rod (39) passes through the cover (20) and enters and exits the bush (25), and the tip of the piston rod (39) is pushed into the bush (25 by the restoring force of the spring. ) The valve body (26) and the tip of the piston rod (39) are separated from each other in the state of protruding outward, and the piston in the state of the tip of the piston rod (39) entering the bush (25) by compressed air A degassing apparatus for a mold, wherein the top of the valve body (26) is pushed in at the tip of the rod (39) . The tip surface of the valve body (26) that contacts the molten metal is formed into a smooth surface, and the degree of smoothness is such that the bubble body (26) separates and maintains the closed state with the momentum of removing the surplus member (30) when the mold is opened. 2. The degassing apparatus for a mold according to claim 1, wherein The closing valve (13) is provided in the bush (25) so that the tip of the valve main body (26) can be projected and retracted, and a clearance for protruding and retracting is provided between the tip of the valve main body (26) and the bush (25). A passage is opened with the tip of the valve body (26) protruding from the bush (25) ,
Although there is a clearance between the tip of the valve body (26) and the bush (25) when the tip of the valve body (26) is immersed in the bush (25) by the pushing movement of the pressure receiving pin (12), Thereafter, the bush (25) and the tip of the valve main body (26) are thermally expanded by the heat of the molten metal reaching the closing valve (13), and the passage is made inaccessible in a close state with no clearance. The degassing apparatus for a mold according to claim 2. The mold degassing device (9) includes a fixed mold (10) and a movable mold (11), and a passage (8) leading to the cavity (5) is formed by the fixed mold (10) and the movable mold (11). In addition, a closing valve (13) in which the valve body (26) slides in the cylindrical bush (25) is provided on the outlet side of the passage (8), and a pressure receiving pin ( 12) is provided to be slidable, and the lever (14) supported in a swingable manner is provided such that the intermediate portion of the lever (14) can be pushed in by the pressure receiving pin (12), and the tip of the lever (14) is provided at the valve body (26). The pushing movement of the pressure receiving pin (12) due to the rise of the molten metal pressure in the passage (8) is changed to the forward movement of the valve body (26) via the lever (14), thereby closing the valve (13 )
An opening cylinder (15) for opening the closing valve (13) is provided in the stationary mold (10), and the opening cylinder (15) is provided so that the top of the valve body (26) can be pushed in directly,
The front end surface of the valve body (26) that contacts the molten metal is formed into a smooth surface, and the degree of smoothness is such that the bubble body (26) is separated and maintained in a closed state with the momentum of removing the surplus member (30) when the mold is opened. Degree,
Closing valve (13) is provided retractably the leading end of the bush (25) the valve body within (26), clearance scan for infested between the tip and the bushing of the valve body (26) (25) The passage (8) is opened with the tip of the valve body (26) protruding, and the passage (8) is not open with the tip of the valve body (26) being immersed,
The mold degassing device (9) is attached to the fixed mold (1) and the movable mold (2), the melt is filled in the cavity (5), and the molten metal overflowing from the cavity (5) is used for the mold. It flows into the passage (8) of the gas venting device (9), pushes the pressure receiving pin (12), moves the valve body (26) indirectly through the lever (14), and closes the closing valve (13). The bush (25) thermally expanded by the heat of the molten metal and the tip of the valve body (26) are in close contact with each other, and after the molten metal has solidified, the mold is opened to take out the surplus member (30). (25) and wait until the clearance between the valve body (26) and the tip of the valve body (26) is formed, and then actuate the open cylinder (15) to push the valve body (26) directly into the closing valve (13). Specially open Using molds venting device according to.

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