JP2012125831A - Casting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a decompression type casting apparatus that prevents the air on the back side of a plunger tip in a sleeve from leaking in a cavity by passing through a space between the plunger tip and the sleeve by a simpler configuration than before.SOLUTION: The casting apparatus 2 includes: a mold 10; a vacuum pump 84; the sleeve 20; the plunger tip 32; a rod 34; and a closing mechanism 60 for closing a molten metal feeding port 22 of the sleeve 20. A rear end of the sleeve 20 is closed by a lid 40. The lid 40 has a rod insertion hole 44 through which the rod 34 can be inserted. A packing 42 is installed around the rod insertion hole 44 to seal the hole.

Description

  The present invention relates to a casting apparatus. In particular, the present invention relates to a so-called reduced pressure casting apparatus that decompresses the inside of a mold cavity and injects molten metal (molten metal) into the mold to cast a product. The “casting apparatus” referred to in this specification is sometimes called a “die casting machine”.

  A casting apparatus that performs casting by depressurizing the inside of a mold cavity and injecting a molten metal into the cavity is typically a mold, a pump for decompressing the inside of the mold cavity, and the cavity A sleeve for temporarily storing the molten metal to be poured into the plunger; a plunger tip for reciprocating in the sleeve to inject the molten metal into the mold; and a rod connected to the rear end portion of the plunger tip. The sleeve has a cylindrical shape, the front end communicates with the mold cavity, and the rear end is open. The rod is advanced / retracted by the actuator. That is, the plunger tip moves forward / backward through the rod. In such a casting apparatus, as the inside of the mold cavity is depressurized during casting, the space in the sleeve on the front side of the plunger tip becomes negative. On the other hand, since the rear end of the sleeve is open, the rear side of the plunger tip is always at atmospheric pressure. Therefore, the pressure difference between the front side and the rear side of the plunger tip during casting becomes large, and the air on the rear side of the plunger tip leaks into the cavity through a slight gap between the plunger tip and the sleeve, or There is a possibility that lubricant applied to the outer peripheral surface of the plunger tip, dust on the rear side of the plunger tip, etc. may enter the front side (that is, the cavity side) of the plunger tip.

  Therefore, for example, Patent Document 1 proposes a casting apparatus that is devised so that air on the rear side of the plunger tip does not easily leak to the front side (that is, the cavity side) of the plunger tip. The casting apparatus includes a closing member that surrounds the molten metal supply port and the open portion of the rear end of the sleeve to form a decompression chamber. The pump depressurizes the decompression chamber and the cavity of the mold, so that both pressures are the same. Since the decompression chamber and the cavity are decompressed equally during casting, there is no pressure difference between the rear side and the front side of the plunger tip in the sleeve. As a result, the air or the like on the rear side of the plunger tip is prevented from leaking to the front side (ie, the cavity side) of the plunger tip.

JP 2008-93712 A

  The casting apparatus of Patent Document 1 requires a closing member that closes the open portion of the rear end of the sleeve and the molten metal supply port of the sleeve. In addition, the pump requires a large power to decompress the decompression chamber together with the cavity. For this reason, the structure of the casting apparatus of Patent Document 1 tends to be complicated. As a result, the entire apparatus may become large. There is a demand for a casting apparatus that can suppress leakage of air or the like on the back surface side of the plunger tip in the sleeve to the front surface side (that is, the cavity side) of the plunger tip with a simpler configuration than the conventional one.

  The casting apparatus disclosed in this specification includes a mold, a pump for decompressing the inside of the mold cavity, a sleeve for temporarily storing a molten metal to be injected into the mold cavity, And a plunger tip connected to the rear end of the plunger tip and moving back and forth by an actuator, and a closing mechanism for closing the molten metal supply port of the sleeve. The rear end of the sleeve is closed by a lid, and a rod insertion hole through which the rod can be inserted is opened in the lid, and the periphery of the rod insertion hole is sealed.

  The pump, actuator and closing mechanism are controlled by the controller of the casting apparatus. After the molten metal is supplied into the sleeve, the controller controls the closing mechanism to close the molten metal supply port, drives the pump to depressurize the cavity, and advances the plunger tip to inject the molten metal into the cavity. The actuator is controlled to make it happen.

  According to the above casting apparatus, when the plunger tip is advanced and the molten metal is injected into the cavity, the space in the sleeve on the rear side of the plunger tip is decompressed by the advancement of the plunger tip. As a result, the pressure difference between the pressure in the front space of the plunger tip that leads to the cavity to be decompressed by the decompression device and the pressure in the space in the sleeve on the rear side of the plunger tip is Compared to the reduced pressure casting apparatus having the structure as described above. In this casting apparatus, the closing mechanism only needs to be able to close only the molten metal supply port of the sleeve. Therefore, the configuration of the casting apparatus is simplified compared to the configuration of the casting apparatus of Patent Document 1. Therefore, it is possible to suppress leakage of air or the like on the rear side of the plunger tip in the sleeve to the front side (that is, the cavity side) of the plunger tip with a simpler configuration than the conventional one.

  The casting apparatus further includes a dust discharge valve that opens when the pressure in the sleeve inner space on the rear side of the plunger tip becomes equal to or higher than a predetermined pressure, and communicates the space in the sleeve on the rear side of the plunger tip with the outside. It is preferable.

  The controller of the casting apparatus provided with this configuration executes the following processing. The controller controls the closing mechanism to close the melt supply port after the melt is supplied into the sleeve. The controller then controls the pump to depressurize the cavity and the actuator to advance the plunger tip to inject molten metal into the cavity. Next, the controller controls the closing mechanism to open the molten metal supply port while the plunger tip is advanced to the forward end. Next, the controller controls the closing mechanism to close the molten metal supply port again after recovering the internal pressure of the sleeve. The controller then controls the actuator to retract the plunger tip until the dust discharge valve opens.

  According to the casting apparatus, the pressure in the sleeve inner space on the rear side of the plunger tip increases as the plunger tip moves backward. The dust discharge valve opens when the space in the sleeve on the rear side of the plunger tip becomes a predetermined pressure or higher. Therefore, according to the above casting apparatus, by opening the dust discharge valve, it is possible to discharge dust such as molten metal pieces remaining in the sleeve together with high-pressure air discharged from the sleeve to the outside of the sleeve. .

A schematic sectional view of a casting device (blocking process). The figure which shows operation | movement of a casting apparatus (injection process). The figure which shows operation | movement of a casting apparatus (internal pressure recovery process). The figure which shows operation | movement of a casting apparatus (backward process). The figure which shows operation | movement of a casting apparatus (dust discharge process).

  The casting apparatus 2 of the present embodiment will be described with reference to the drawings. The casting apparatus 2 of the present embodiment is a reduced pressure casting apparatus (so-called reduced pressure die casting machine or vacuum die casting machine) that decompresses the inside of a mold cavity and injects molten metal (molten metal) into the mold to cast a product. . As shown in FIG. 1, the casting apparatus 2 includes, as main components, a mold 10, a sleeve 20 for temporarily storing molten metal supplied to the mold 10, and a plunger that reciprocates in the sleeve 20. 30, a lid 40 for closing the rear end of the sleeve 20, a dust discharge valve 50 for discharging dust in the sleeve 20, and a closing mechanism 60 for closing and opening a molten metal supply port 22 (described later) of the sleeve 20. A pressure reducing valve 70 provided in the mold 10, a pressure reducing mechanism 80 for reducing the pressure in a cavity 16 (described later) of the mold 10, and a controller 90. The casting apparatus 2 of the present embodiment is a horizontal casting apparatus in which the sleeve 20 is provided with its longitudinal direction substantially horizontal, and the plunger 30 reciprocates in the horizontal direction in the sleeve 20. Although FIGS. 1 to 5 are cross-sectional views, the plunger 30, the dust discharge valve 50, the closing mechanism 60, and the pressure reducing valve 70 are shown in a side view and a pressure reducing mechanism 80 in order to help understand the structure of the casting apparatus 2. Note that this is shown schematically.

  The mold 10 includes a fixed mold 12 and a movable mold 14. Both the fixed mold 12 and the movable mold 14 are alloy steel molds. The fixed mold 12 is fixed to a fixed plate (not shown). The movable mold 14 is fixed to a movable plate (not shown). As the movable platen moves, the movable mold 14 comes into close contact with / separates from the fixed mold 12. Note that bringing the molds into close contact with each other is referred to as “closing the mold”, and separating the molds that are in close contact with each other is referred to as “opening the mold”. FIG. 1 shows a state when the mold is closed (when the movable mold 14 is in close contact with the fixed mold 12). At this time, a cavity 16 for casting the product is formed between the two molds 12 and 14.

  The sleeve 20 is a cylindrical member made of alloy steel. In the upper part near the rear end of the sleeve 20, a molten metal supply port 22 for supplying molten metal into the sleeve 20 from the outside is opened. The front end of the sleeve 20 is fixed to the fixed mold 12. The internal space of the sleeve 20 communicates with the cavity 16. Here, “front (backward) of the sleeve 20” means the forward (backward) direction of the reciprocating plunger 30.

  The plunger 30 includes a plunger tip 32 and a rod 34. The plunger tip 32 is a columnar member made of alloy steel for extruding the molten metal in the sleeve 20 into the cavity, and is arranged in the sleeve 20 so that the tip surface thereof faces the space in the sleeve 20. The plunger tip 32 has a diameter (strictly a slightly smaller diameter) at which the outer peripheral surface of the plunger tip 32 and the inner peripheral surface of the sleeve 20 are in contact with each other with almost no gap.

  The rod 34 is connected to the rear end of the plunger tip 32 and supports the plunger tip 32. The rear end of the rod 34 is connected to the actuator 36. The actuator 36 moves the plunger 30 forward and backward. The actuator 36 is, for example, a hydraulic device. As the rod 34 moves back and forth by the actuator 36, the plunger tip 32 reciprocates back and forth within the sleeve 20.

  The lid 40 is a member that closes the rear end of the sleeve 20. The lid 40 is formed in a bottomed cylindrical shape, and the inner diameter thereof is formed such that the outer peripheral surface of the plunger tip 32 and the inner peripheral surface of the lid 40 are in contact with each other with almost no gap. The opening end of the lid 40 is closely fixed to the rear end of the sleeve 20 by fixing means such as a bolt (not shown). A rod insertion hole 44 having a diameter through which the rod 34 can be inserted is opened at the bottom center of the lid 40. A packing 42 that seals a gap between the outer peripheral surface of the rod 34 and the inner peripheral surface of the rod insertion hole 44 is provided on the inner peripheral surface of the rod insertion hole 44.

  The dust discharge valve 50 is an on-off valve for communicating the internal space of the sleeve 20 with the outside, and is provided at the lower part of the lid 40. The dust discharge valve is an open / close valve (check valve) that opens when the pressure in the internal space of the sleeve 20 on the rear side of the plunger tip 32 becomes equal to or higher than a predetermined pressure. The dust discharge valve 50 is connected to the lid 40 and communicates with the internal space of the lid 40 (that is, the internal space of the sleeve 20), the lid portion 52 that closes the end of the cylindrical portion 51, and the lid portion 52. And a spring 54 used for opening and closing. The spring 54 is a coil spring as shown in the figure, and is a tension spring that urges both ends in a direction of pulling each other. An upper end portion of the spring 54 is fixed to a locking rod 53 provided in the cylindrical portion 51, and a lower end portion of the spring 54 is fixed to the lid portion 52. Accordingly, when the pressure in the inner space of the sleeve 20 is smaller than the predetermined pressure, the lid 52 is held in a state of closing the end of the cylindrical portion 51 by the biasing force of the spring 54. When the pressure in the inner space of the sleeve 20 becomes equal to or higher than a predetermined pressure, the lid portion 52 is pushed by the air that has become high pressure in the sleeve 20 and the cylindrical portion 51 is opened. At this time, together with the high-pressure air in the sleeve 20 from the opened end of the cylinder portion 51, dust such as molten metal pieces remaining in the sleeve 20 (hereinafter referred to as “dusts”) Is discharged to the outside.

  The closing mechanism 60 is a mechanism for closing and opening the molten metal supply port 22 of the sleeve 20, and is provided above the sleeve 20. The closing mechanism 60 includes a closing plate 62, a rod 64, and an elevating device 66. The closing plate 62 is a plate-like member having a shape capable of tightly closing the molten metal supply port 22 of the sleeve 20. When the closing plate 62 contacts the outer peripheral surface of the sleeve 20 in a range including the molten metal supply port 22, the molten metal supply port 22 is closed. A packing (not shown) for sealing a gap between the outer peripheral surface of the sleeve 20 and the surface of the closing plate 62 is provided on the surface (the lower surface in the drawing) of the closing plate 62 that is in contact with the sleeve 20. Is provided. The rod 64 is connected to a surface (upper surface in the drawing) of the closing plate 62 that does not contact the sleeve 20. The upper end of the rod 64 is connected to an elevating device 66 for moving the closing plate 62 up and down. The lifting device 66 is an actuator such as a hydraulic device, for example.

  The pressure reducing valve 70 is an on-off valve for controlling the discharge of air in the cavity 16. The pressure reducing valve 70 is provided so as to communicate with the cavity 16 of the mold 10. When the decompression valve 70 is open, the air in the cavity 16 can be discharged by the decompression mechanism 80. When the pressure reducing valve 70 is closed, the air in the cavity 16 cannot be discharged.

  The decompression mechanism 80 is connected to the decompression valve 70 and is a mechanism for discharging the air in the cavity 16 of the mold 10 to decompress the inside of the cavity 16. The decompression mechanism 80 includes a vacuum tank 82 and a vacuum pump 84 that sucks gas (air) in the vacuum tank 82 to the outside. The inside of the vacuum tank 82 is maintained at a predetermined pressure (a predetermined degree of vacuum) by intermittent operation of the vacuum pump 84. Therefore, by operating the vacuum pump 84 with the pressure reducing valve 70 opened, the air in the cavity 16 can be discharged through the pressure reducing valve 70 and the vacuum tank 82.

  In addition to the above members, the casting apparatus 2 includes a controller 90 for controlling operations of the movable mold 14, the plunger 30 (actuator 36), the closing mechanism 60, the pressure reducing valve 70, and the pressure reducing mechanism 80 (vacuum pump 84). It has. Further, the casting apparatus 2 is provided with a molten metal supply device (not shown) for supplying an amount of molten metal necessary for casting the product into the sleeve 20.

  Processing executed by the controller 90 will be described with reference to FIGS. Below, the casting process by the casting apparatus 2 is divided into a closing process (see FIG. 1), an injection process (see FIG. 2), an internal pressure recovery process (see FIG. 3), a retreating process (see FIG. 4), and a dust discharging process (see FIG. The process is divided into five steps (see FIG. 5), and processing executed by the controller 90 in each step is described. The closing step (see FIG. 1) is a step of closing the molten metal supply port 22 after supplying the molten metal H into the sleeve 20. The injection step (see FIG. 2) is a step of casting the product by moving the plunger tip 32 forward and injecting the molten metal H in the sleeve 20 into the cavity 16. The internal pressure recovery step (see FIG. 3) is a step of opening the molten metal supply port 22 after the molten metal H is injected to recover the internal pressure in the sleeve 20. The retreat process (see FIG. 4) is a process in which the molten metal supply port 22 is closed again after the internal pressure of the sleeve 20 is recovered, and the plunger tip 32 is retreated to its original position. The dust discharge process (see FIG. 5) is a process of opening the dust discharge valve 50 and discharging the dust in the sleeve 20 in the process of retracting the plunger tip 32.

(1. Blocking process)
First, the controller 90 operates the movable platen to press the movable mold 14 against the fixed mold 12 to form the cavity 16 between the two molds 12 and 14. Further, the controller 90 controls the actuator 36 so that the plunger 30 is positioned at the retracted end (position shown in FIG. 1). At this time, the distal end surface of the plunger tip 32 is located behind the molten metal supply port 22. At this time, the controller 90 controls the closing mechanism 60 to keep the molten metal supply port 22 open. In this state, the molten metal H is supplied into the sleeve 20 by the molten metal supply device. When the molten metal H is supplied into the sleeve 20, the controller 90 operates the elevating mechanism 66 to close the molten metal supply port 22 with the closing plate 62 as shown in FIG. 1. Thereby, the space in the sleeve 20 before and after the plunger tip 32 is sealed.

(2. Injection process)
Next, the controller 90 drives the vacuum pump 84 and opens the pressure reducing valve 70. Thereby, the discharge of air in the cavity 16 and in the space 24 on the front side of the plunger tip 32 of the sleeve 20 (hereinafter referred to as the front space 24) is started (see FIG. 2). That is, pressure reduction in the cavity 16 and the front space 24 is started. Controller 90 then controls actuator 36 to advance plunger tip 32. As shown in FIG. 2, when the plunger tip 32 moves forward, the molten metal H in the sleeve 20 is pushed by the distal end surface of the plunger tip 32. At the same time, the volume of the sleeve inner space 26 (hereinafter referred to as the rear space 26) on the rear side of the plunger tip 32 is increased. As described above, since the rear space 26 is sealed, the inside of the rear space 26 has a negative pressure. That is, the pressure in the rear space 26 is reduced as the plunger tip 32 advances. The molten metal H pushed with the advancement of the plunger tip 32 is injected into the cavity 16 of the mold 10. As a result, the pressure difference between the pressure in the cavity 16 and the front space 24 and the pressure in the rear space 26 becomes smaller than that of the decompression device configured to always have the atmospheric pressure on the rear side of the plunger tip. Therefore, the air in the rear space 26, the lubricant on the outer periphery of the plunger tip 32, and the like (hereinafter referred to as air) can be prevented from leaking into the front space 24. When the plunger tip 32 advances to a predetermined advance end (position shown in FIG. 3), the molten metal H in the sleeve 20 is filled into the cavity 16 (see FIG. 3).

(3. Internal pressure recovery process)
As shown in FIG. 3, the plunger tip 32 advances to the advance end, whereby the molten metal H in the sleeve 20 is filled into the cavity 16, and the product is cast in the cavity 16. When the plunger tip 32 is advanced to the advance end, the controller 90 stops the vacuum pump 84 and closes the pressure reducing valve 70. Further, as shown in FIG. 3, the controller 90 operates the elevating device 66 to raise the closing plate 62 and open the molten metal supply port 22. At this time, the plunger tip 32 remains advanced to the forward end. When the molten metal supply port 22 is opened, the internal pressure of the rear space 26 that was a negative pressure is recovered. Here, “the internal pressure of the rear space 26 recovers” means that the internal pressure of the rear space 26 returns from the negative pressure to the original atmospheric pressure. Thereafter, when the predetermined time has elapsed and the molten metal in the cavity 16 has solidified, the controller 90 operates the movable plate to separate the movable mold 14 from the fixed mold 12. Thereafter, the product is taken out from the mold 10 by a known method.

(4. Backward process)
After the product is taken out from the mold 10 and when the plunger tip 32 is still at the forward end, the controller 90 operates the lifting device 66 again to lower the closing plate 62 and supply the molten metal again. The mouth 22 is closed (see FIG. 4). Thereby, the rear space 26 is sealed again. At this time, the internal pressure of the rear space 26 is atmospheric pressure (normal pressure). Next, the controller 90 operates the actuator 36 to retract the plunger tip 32 as shown in FIG. As the plunger tip 32 moves backward, the volume of the rear space 26 is reduced. As described above, since the rear space 26 is sealed, the air in the rear space 26 is compressed. That is, the pressure in the rear space 26 increases as the plunger tip 32 moves backward.

(5. Dust discharging process)
As the plunger tip 32 moves backward, when the pressure in the rear space 26 becomes equal to or higher than a predetermined pressure, the lid 52 of the dust discharge valve 50 is pushed by the air that has become high pressure in the rear space 26, and is shown in FIG. Thus, the cylinder part 51 is opened. At this time, the dust 58 remaining in the sleeve 20 is discharged to the outside from the open end of the cylindrical portion 51 together with the air that has become high pressure in the rear space 26. When the air in the rear space 26 is discharged and the interior of the rear space 26 becomes smaller than a predetermined pressure, the lid portion 52 again closes the end portion of the cylindrical portion 51. When the plunger tip 32 is retracted to the original position (the position shown in FIG. 1), the controller 90 operates the elevating device 66 to raise the closing plate 62, open the molten metal supply port 22, and again introduce the molten metal into the sleeve 20. Make it ready for supply. It is known in advance how the pressure in the sleeve 20 changes as the plunger tip moves forward / backward. Therefore, it can be known in advance how far the plunger tip 32 is retracted to raise the pressure in the rear space 26 to a pressure sufficient to open the dust discharge valve 50. Based on such a priori information, the position to retract the plunger tip 32 is determined. Therefore, the process of the controller 90 when retracting the plunger tip 32 can be expressed as “a process of controlling the actuator 36 to retract the plunger tip 32 until the dust discharge valve is opened”.

  In the above, the casting apparatus 2 of a present Example was demonstrated. According to the casting apparatus 2 of the present embodiment, the molten metal supply port 22 is closed, and when the plunger tip 32 is advanced to inject the molten metal into the cavity 16, the rear space 26 is accompanied by the advancement of the plunger tip 32. The inside is depressurized (see FIGS. 1 and 2). As a result, the pressure difference between the pressure in the cavity 16 and the front space 24 that is decompressed by the decompression mechanism 80 and the pressure in the rear space 26 is such that the rear side of the plunger tip is always at atmospheric pressure. Smaller than the device. In the casting apparatus 2, the closing mechanism 60 only needs to be able to close only the molten metal supply port 22 of the sleeve 20. Therefore, the structure of the casting apparatus 2 is compared with the structure of a conventional casting apparatus (for example, Patent Document 1) in which a closing member capable of closing and opening the open portion of the rear end of the sleeve and the molten metal supply port is required. And simple. Therefore, air or the like in the rear space 26 in the sleeve 20 can be prevented from leaking to the front space 24 with a simpler configuration than in the past.

  Further, according to the casting apparatus of the present embodiment, the molten metal supply port 22 is closed after the internal pressure of the rear space 26 of the sleeve 20 is recovered once, and then the plunger tip 32 is retracted, whereby the inner space of the rear space 26 is increased. The pressure increases (see FIG. 4). When the pressure in the rear space 26 becomes equal to or higher than a predetermined pressure, the lid portion 52 of the dust discharge valve 50 is pushed by the air that has become high pressure in the rear space 26, and the cylinder portion 51 is opened (see FIG. 5). . At this time, the dust 58 remaining in the sleeve 20 can be discharged to the outside together with the air that has become high pressure in the rear space 26 from the opened end of the cylindrical portion 51. The dust in the sleeve 20 can be easily discharged to the outside.

The modifications of the above embodiment are listed below.
(1) The dust discharge valve 50 is not limited to the open / close valve having the structure shown in FIGS. 1 to 5, and may have any structure as long as it opens when the internal pressure of the rear space 26 exceeds a predetermined pressure. There may be.
(2) It is good also as a structure provided with the air ejection mechanism which can eject high pressure air in the cylinder part 51 of the dust discharge valve 50, and can open the cover part 52 by injecting high pressure air. In this case, even if the dust discharge valve 50 is opened due to a pressure increase in the rear space 26 accompanying the retraction of the plunger tip 32, even if the dust is not sufficiently discharged, the air ejection mechanism The lid 52 can be opened by ejecting high-pressure air from the container, and the dust can be sufficiently discharged.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Casting apparatus 10: Mold 12: Fixed mold 14: Movable mold 16: Cavity 20: Sleeve 22: Molten supply port 24: Front space 26: Rear space 30: Plunger 32: Plunger tip 34: Rod 36: Actuator 40: Lid 42: Packing 44: Rod insertion hole 50: Dust discharge valve 51: Tube part 52: Lid part 53: Locking rod 54: Spring 58: Dust 60: Closure mechanism 62: Closure plate 64: Rod 66: Lifting device 70: Pressure reducing valve 80: Pressure reducing mechanism 82: Vacuum tank 84: Vacuum pump 90: Controller H: Molten metal

Claims (4)

Mold,
A pump for decompressing the inside of the mold cavity;
A sleeve for temporarily storing molten metal for injection into the mold cavity;
A plunger tip disposed in a sleeve so as to be reciprocally movable;
A rod connected to the rear end of the plunger tip and moving back and forth by an actuator;
A closing mechanism for closing the molten metal supply port of the sleeve;
With
The rear end of the sleeve is closed by a lid,
The lid has a rod insertion hole through which the rod can be inserted,
A casting apparatus characterized in that the periphery of the rod insertion hole is sealed.   A dust discharge valve is provided, which opens when the pressure in the sleeve inner space on the rear side of the plunger tip becomes equal to or higher than a predetermined pressure, and makes the sleeve inner space on the rear side of the plunger tip communicate with the outside. Item 2. The casting apparatus according to Item 1. It has a controller that controls the pump, actuator and blockage mechanism,
Controlling the closing mechanism to close the melt supply port after the melt is supplied into the sleeve;
Driving the pump to depressurize the cavity and controlling the actuator to advance the plunger tip to inject molten metal into the cavity;
The casting apparatus according to claim 1, wherein the casting apparatus is executed. It has a controller that controls the pump, actuator and blockage mechanism,
Controlling the closing mechanism to close the melt supply port after the melt is supplied into the sleeve;
Driving the pump to depressurize the cavity and controlling the actuator to advance the plunger tip to inject molten metal into the cavity;
Controlling the closing mechanism to open the melt supply port with the plunger tip advanced to the forward end;
Controlling the closing mechanism to close the molten metal supply port again after the sleeve internal pressure is recovered;
Controlling the actuator to retract the plunger tip until the dust discharge valve opens;
The casting apparatus according to claim 2, wherein:

Images