KR101760508B1 - Centrifugal casting machine - Google Patents

Abstract

The present invention relates to a centrifugal casting apparatus, and more particularly, to a centrifugal casting apparatus having a main frame (10) having a frame structure with front, rear, left and right side openings; A main shaft 20 installed through the center of the main frame 10 and rotated by a motor M; A lower mold (30) installed on the upper surface of the main frame (10) and rotated by the main shaft (20); A lower plate 40 installed on the inner side of the main frame 10 and operated to move up and down; An upper plate 50 mounted on the upper mold 30 and operated to move up and down by the lower plate 40; An upper mold 60 rotatably installed on a bottom surface of the upper plate 50 and closely contacting the lower mold 30 by a lowering operation of the upper plate 50; And an ejector 70 positioned below the lower mold 30 and discharging the product cast by the elevating operation from the lower mold 30. According to the present invention, So that the defective product can be prevented.

Description

Centrifugal casting machine equipped with rotary mold heating /

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal casting apparatus, and more particularly, to a centrifugal casting apparatus having a rotary mold heating and cooling means for casting a product using a centrifugal casting method after injecting a hot molten metal into the upper and lower molds .

Generally, when making castings, molten metal is injected into a mold by the action of gravity. This method has a limitation in manufacturing a casting of a dense structure. In order to solve this problem, there has been proposed a centrifugal casting method in which casting of a dense texture is obtained by pouring a casting material into a casting mold while rotating. Such a centrifugal casting method is a casting method in which a casting requiring a good pressure resistance such as a tube, a cylinder liner, It is very advantageous to manufacture such a semiconductor device.

A centrifugal casting machine generally used in the centrifugal casting process is composed of a disk-shaped face plate rotated by a motor, a mold held and rotated on the face plate, and a pouring mechanism for pouring molten metal into the mold. When the molten metal is injected through the mechanism, the molten metal is pressed against the inner surface of the mold by the centrifugal force, and the molten metal is hardened in this state, so that the fine structure of the structure can be obtained.

In the centrifugal casting method as described above, the temperature of the molten metal injected into the mold, the injection capacity, the rotational speed of the mold, and the cooling rate greatly affect the quality of the final casting.

Among them, the cooling rate of the casting is a very important factor directly related to the compactness of the casting structure and the occurrence frequency of defects. Conventionally, a natural cooling method has been mainly used in which a mold placed on a face plate after casting using a centrifuge is left in the atmosphere.

However, in the case of the natural cooling by the atmospheric deposition using the centrifugal casting machine of the prior art, even cooling over the entire casting mold can not be expected.

This is because the lower part of the casting mold is in surface contact with the face plate and the atmosphere contact is obstructed. Therefore, the atmospheric cooling method by the conventional centrifugal casting machine can not maintain the uniform atmospheric contact throughout the casting, A shrinkage phenomenon toward the casting center occurs, and cracks are generated, which is a disadvantage in that the defective rate during casting is very high.

In addition, since the upper and lower plates of the casting mold are locally melted during casting due to the high molten metal temperature, it is not easy to separate the casting from the casting mold after centrifugal casting in the past, and the upper and lower molds are tightly adhered to each other, However, there is a problem that the slip occurs due to the rotation speed and the product is defective.

KR 10-1121779 B1 KR 10-1566706 B1 KR 10-1494553 B1 KR 10-1138486 B1

Accordingly, it is an object of the present invention to solve the problems of the conventional centrifugal casting apparatus as described above, and the upper and lower molds of the centrifugal casting apparatus can be tightly contacted with each other and rotated together, And it is an object of the present invention to provide a centrifugal casting apparatus capable of rapidly cooling a molten metal when necessary without being easily cooled.

According to an aspect of the present invention, there is provided a centrifugal casting apparatus including: a main frame having a frame structure having front, rear, left and right sides opened; A main shaft installed through the center of the main frame and rotated by the motor; A lower mold installed on an upper surface of the main frame and rotated by a main shaft; A lower plate installed inside the main frame and operated to move up and down; An upper plate installed on an upper portion of the lower mold and operated to move up and down by the lower plate; An upper mold which is rotatably installed on a bottom surface of the upper plate and is brought into close contact with the lower mold by a lowering operation of the upper plate; And an ejector which is located at a lower portion of the lower mold and discharges the product cast by the lifting operation from the lower mold.

Further, the inner side of the lower mold and the upper mold of the present invention may further include a heating device for heating each of the lower mold and the upper mold by applying power and generating heat.

The power supply unit supplies electric power to the power supply plate. The lower mold and the upper mold are provided with an outer side surface and a lower side surface, respectively. A contact plate may be provided so as to face each other so that power is supplied to the heating device even during a rotation operation of the lower mold and the upper mold.

Further, the present invention may further include a blowing fan installed in the main frame to supply cooling air along the outer circumferential surfaces of the lower mold and the upper mold.

In addition, the present invention can be configured such that a plurality of air holes are radially formed on the lower side of the lower mold and the upper side of the upper mold, and the air holes are supplied to the air holes of the lower mold from the blowing fan.

According to another aspect of the present invention, there is provided a plasma display panel comprising: a main plate having a lower plate disposed between a bottom plate and an upper plate of a main frame; A first elevating device for vertically moving the main lifting plate while the cylinder is fixed to the bottom plate and the rod is fixedly installed through the bottom surface of the main lifting steel plate; And a second lifting device for lifting and lowering the upper plate by lifting and lowering the main lifting steel plate while one end is fixed to the upper surface of the main lifting steel plate and the other end is fixed to the bottom surface of the upper plate through the upper plate .

Further, the lower plate of the present invention includes an auxiliary lifting plate installed at a predetermined distance from the bottom of the main lifting steel plate; Further comprising a lifting unit for lifting and lowering the auxiliary lifting plate by a rod being pulled in and out by fixing the cylinder to the bottom surface of the auxiliary lifting steel plate and fixing the rod to the bottom surface of the main lifting steel plate through the auxiliary lifting steel plate, The upper surface of the auxiliary lifting plate is provided with a lifting rod whose one end is fixed to the auxiliary lifting plate and the other end is protruding upward through the second lifting device. The upper end of the lifting rod is spaced apart from the upper surface of the upper plate by a predetermined distance, And a lifting plate having a casting mold for injecting the molten metal into the inside of the upper mold.

According to the present invention, when the pressing springs are provided on the lifting rods between the upper plate and the lifting plate and the upper mold is lowered and brought into close contact with the lower mold by the lowering operation of the upper plate, And can be configured to rotate while being strongly adhered to each other.

In addition, a bearing unit may be installed between the upper plate and the upper mold.

In this case, the bearing unit of the present invention includes: an upper bearing portion having a flange protruding along an upper periphery thereof and hooked on the upper plate; A lower bearing portion having a ring shape and positioned at a predetermined distance from the bottom surface of the upper bearing portion and having an upper mold fixed to the lower surface thereof; And a cylindrical roller-type rolling bearing including a plurality of rollers having a cylindrical shape provided between the upper and lower bearing portions.

The present invention relates to a centrifugal casting apparatus for casting a product using a centrifugal casting method, in which a state in which the upper and lower metal molds are tightly adhered to each other is maintained as it is and is rotated together with the casting mold. .

In the present invention, power can be supplied to the upper and lower molds through the main spindle to be rotated. In this way, the upper and lower molds are heated so that the molten metal can sufficiently flow into the molds, So that the shape thereof can be maintained at a high speed, whereby a compact product is cast.

1 is a perspective view showing an example of a centrifugal casting apparatus of the present invention,
Fig. 2 is a front view of Fig. 1,
3 is a partial enlarged view showing an example of the upper and lower molds of the present invention,
4 is a partial perspective view showing an example of upper and lower dies of the present invention,
5 is a partially enlarged view showing a structure in which a lifting rod is provided on a top plate of the present invention by a pressure spring,
Fig. 6 is a partial perspective view showing an example of a conductive part and a conductive plate of the present invention,
FIG. 7 is a use state view showing an example in which the upper mold of the present invention is operated to be lowered,
8 to 10 are use state diagrams showing operation examples of the centrifugal casting apparatus of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention relates to a centrifugal casting apparatus capable of rapidly rotating the upper and lower molds of a centrifugal casting apparatus so that the upper and lower molds can be rotated together and the upper and lower molds are heated at a high temperature, The present invention relates to a main frame 10 having a frame structure having front, rear, left and right sides opened as shown in FIGS. 1 and 2; A main shaft 20 installed through the center of the main frame 10 and rotated by a motor M; A lower mold (30) installed on the upper surface of the main frame (10) and rotated by the main shaft (20); A lower plate 40 installed on the inner side of the main frame 10 and operated to move up and down; An upper plate 50 installed at an upper portion of the lower mold 30 and being operated to move up and down by the lower plate 40; An upper mold 60 rotatably installed on a bottom surface of the upper plate 50 and closely contacting the lower mold 30 by a lowering operation of the upper plate 50; And an ejector 70 which is positioned below the lower mold 30 and discharges the product cast by the elevating operation from the lower mold 30. [

1 and 2, the main frame 10 includes a bottom plate 11 and a bottom plate 11 so that the front, rear, left, and right sides of the main frame 10 are opened. The top plate 12 is firmly supported by providing a plurality of supports 13 between the bottom plate 11 and the top plate 12.

The main shaft 20 installed in the main frame 10 through the center of the upper plate 12 rotates the lower mold 30 to be described later. (Not shown) while being pierced through the base 12.

A power transmission means for transmitting power such as a sprocket or a pulley is provided at a lower portion of the main shaft 20. A motor M for transmitting rotational power to the power transmission means is connected to a bottom plate 11 ).

In the present invention, a speed reducer RB is provided between the motor M and the power transmission means for reducing the rotational force of the motor M to a constant gear ratio so as to rotate the main shaft 20 at a constant speed, Although it is also shown in the drawings attached to the present invention that the power is transmitted by the structure of the belt and the pulley, it is also possible for a person skilled in the art to make a variety of known and widely used It is preferable to transmit the power by the chain and the sprocket in order to more accurately transmit the rotational power of the motor M to the main shaft 20. [

The main shaft 20 is also provided with a cylindrical portion 21 for supplying power to the heating devices 80A and 80B to be described later so as to surround the outer circumferential surface.

3 and 4, the lower mold 30, which is installed on the upper surface of the upper plate 12 of the main frame 10 and is connected to the upper portion of the main shaft 20 and rotated by the rotation of the main shaft 20, A mold is formed in accordance with the product so that the molten metal is injected into the mold while the upper mold 60, which will be described later, is in close contact with the mold so that the product can be cast by the centrifugal casting method.

The lower mold 30 is rotated by the main shaft 20 while being supported by the upper plate 12 fixed to the main frame 10.

Inside the lower mold 30, a heating device 80A for heating the lower mold 30 to prevent the molten metal injected into the molds from being easily cooled for casting is provided. At this time, The power is continuously supplied even during the rotation operation by the conductive part 21 provided on the outer circumferential surface of the main shaft 20 even if the rotation is performed.

A contact plate PL1 for supplying power to the heating devices 80A and 80B provided inside the upper mold 60 to be described later is provided on the outer peripheral surface of the lower mold 30, When the upper mold 60 is moved downward and brought into close contact with the lower mold 30, the contact plates PL1 and PL2 are brought into contact with each other to be energized to move the upper mold 60, The power is supplied to the heating device 80B.

In addition, an ejector 70 for removing the molded product from the lower mold 30 is installed on the bottom surface of the lower mold 30. The elevator 70 is moved up and down by an elevator installed on the separate main frame 10 So that the product positioned inside the lower mold 30 is lifted and discharged to the outside.

The lower plate 40 which is installed between the bottom plate 11 and the upper plate 12 of the main frame 10 and moves up and down is provided with a plurality of A main lifting plate 41 on the upper surface of which a second lifting device 41B is lifted and lowered by the first lifting device 41A to support the bottom surface of the upper plate 50 to move up and down; The cylinder 43A is provided on the auxiliary lift plate 42 and the auxiliary lift plate 42 provided with the lift rod 42A which is installed on the bottom surface of the second lift apparatus 41B and extends through the inside of the second lift apparatus 41B The rod 43B is connected so as to pass upward through the auxiliary lifting steel plate 42. The auxiliary lifting steel plate 42 is lifted and operated in conjunction with the lifting operation of the main lifting steel plate 41, And an elevating unit (43) for elevating and lowering the auxiliary lifting plate (42) independently of the main lifting plate (41) by operation.

That is, the lower plate 40 includes a main lifting plate 41 which is vertically movable at a lower position of the upper plate 12 fixed to the main frame 10, A first elevating device 41A for elevating and lowering the steel plate 41 and a second elevating device 41B having both ends coupled to the main lifting steel plate 41 and the top plate 50, And a second elevating device 41B for elevating and lowering the elevating device 50.

At this time, the cylinders are fixed to the bottom plate 11 of the plurality of first elevating devices 41A and the rods 41A 'of the first elevating devices 41A are fixed to the bottom surface of the main elevating plates 41 As the rod 41A 'is moved in and out of the cylinder, the main lifting plate 41 is lifted and lowered.

With this structure, when the main lifting plate 41 is lifted and lowered, the second lifting device 41B and the lifting and lowering rod 42A are lifted and lowered while the auxiliary lifting plate 42 is lifted and lowered together, do.

At this time, when the upper plate 50 is lowered and the upper mold 60 is further lowered than the upper mold 60, the upper mold 60 and the lower mold 30 come into tight contact with each other, A pressing spring S is installed on the lifting rod 42A between the upper surface of the upper plate 50 and the lifting plate 110 to be described later in order to solve the above problems. Whereby the upper plate 50 is elastically supported by the pressure spring S so as to be downwardly pressed while being vertically movable independently of the second elevating device 41B and the elevating rod 42A.

With this structure, the main lifting steel plate 41 and the auxiliary lifting steel plate 42 are moved downward to descend further than the point where the upper mold 60 and the lower mold 30 come into close contact with each other, The upper plate 50 which is elastically supported by the pressing spring S keeps its position while the pressing spring S is relatively compressed even when the rod 42A further descends and consequently the upper plate 50 is pressed The upper mold 60 and the lower mold 30 are strongly pressed against each other while the spring S is being pressed from the upper surface and the upper mold 60 and the lower mold 30 are prevented from being damaged No slip occurs between the rotating operations.

In addition to the function of bringing the upper mold 60 into close contact with the lower mold 30 as described above, the pressurizing spring S also has an impact that occurs when the upper mold 60 is lowered to come into contact with the upper surface of the lower mold 30. [ Thereby absorbing (buffering) the upper mold 60 and preventing the upper mold 60 from being damaged due to the collision.

2 and 5, a lifting plate 110 is installed at an upper end of a lifting rod 42A installed through the inside of the second lifting device 41B, A spout 111 is installed

When the auxiliary lift plate 42 is independently lowered in a state where the upper mold 60 and the lower mold 30 are in close contact with each other, the lift plate 110 having the above structure is moved down The lower end of the sprue 111 is inserted into the upper mold 60. In this state, the molten metal is poured into the sprue 111 using another robot or the like to inject the molten metal into the molds.

The upper plate 50, which is installed at an upper portion of the lower mold 30 and is moved up and down by the second lifting device 41B of the main lifting steel plate 41, An upper mold 60 to be described later is installed, and a lift steel plate 110 for elevating and lowering the sprue 111 is installed on the upper portion.

The upper mold 60 is rotated together with the lower mold 30 while being closely held by the lower mold 30 rotated by the main shaft 20. To this end, the upper mold 50 is provided with the lower mold 30 And the bearing unit B is installed through the upper plate 50 as shown in FIG. 5 so that the upper plate 50 can be downwardly pressed while the upper plate 50 is downwardly pressed.

The bearing unit B according to the present invention includes an upper bearing portion B1 which is engaged with the upper plate 50 while a flange is protruded along the upper periphery thereof and a lower bearing portion B1 spaced apart from the lower surface of the upper bearing portion B1 A ring-shaped lower bearing portion B2 in which an upper mold 60 is fixedly installed on a bottom surface thereof and a plurality of rollers B3 having a cylindrical shape and provided between the upper and lower bearing portions B1, This structure allows the bearing unit B to smoothly move in the state in which the upper plate 50 is lowered and the upper mold 60 is pressed against the lower mold 30 so as to be in close contact with the lower mold 30. [ The upper bearing part B1 is supported by the upper plate 50 so that the upper plate 50 is supported by the upper plate 50 even if the upper plate 50 is raised and the upper mold 60 is separated from the lower mold 30. [ The jammed state is The upper mold 60 is lifted and lowered together with the upper plate 50.

As shown in FIG. 3, the upper mold 60 rotatably installed on the upper plate 50 is formed with a mold having various shapes according to products to be cast on its bottom surface as in the case of the lower mold 30, A through hole 61 penetrating vertically is formed at the center.

Another contact plate PL2 is provided on the outer circumferential surface of the upper mold 60 in correspondence with the position of the contact plate PL1 provided on the outer circumferential surface of the lower mold 30 and the power supplied from the power supply unit 90 The heating device 80B applied to the upper mold 60 through the contact plate PL1 of the lower mold 30 while being applied to the upper mold 60, So that the upper mold 60 is appropriately heated such that the molten metal is not cooled rapidly during the casting process, like the lower mold 30.

As described above, the heating devices 80A and 80B are installed inside the lower mold 30 and the upper mold 60. These heating devices 80A and 80B are made of various kinds of heating elements which are widely used and widely used And may be provided so as to be in close contact with the outer side or the bottom surface of the upper mold 30 and the upper surface of the upper mold 60, if necessary.

6, in order to supply necessary power to the heating devices 80A and 80B of the lower mold 30 and the upper mold 60 through the main spindle 20 rotating in the present invention, And a power supply unit 90 for supplying electric power to the power supply unit 91. The power supply unit 90 includes a power supply unit 91 and a power supply unit 90. The power supply unit 90 is disposed on a side surface of the power supply unit 21,

At this time, the conductive part 21 is formed in a structure in which grooves are repeatedly formed at regular intervals, and the conductive plate 91 is formed in a square bar shape having a predetermined width and length inserted into the grooves of the conductive part 21, The conductive plate 91 is fixedly attached to the conductive part 21 so as to be in tight contact with the conductive part 21 so that the conductive plate 91 is electrically connected to the conductive part 21, The power supply is stably supplied.

1 and 2, the bottom plate 11 of the main frame 10 is provided with a blowing fan 100 (see FIG. 1) And the air is supplied to the bottom surface of the lower mold 30 through the air blowing pipe 101 by the blowing fan 100.

At this time, a plurality of air holes H are radially formed on the bottom surface of the lower mold 30 so that the air supplied from the blowing fan 100 flows into the bottom surface of the lower mold 30 through the air holes H so as to be cooled A plurality of air holes H are formed radially around the bearing unit B located on the upper side of the upper mold 60. Air supplied from the blowing fan 100 flows into the upper mold 60, 60 are cooled.

8, when the rod 41A 'of the first elevating device 41A is drawn into the inside of the cylinder, the centrifugal casting apparatus of the present invention having the above structure, The upper plate 50 is lowered and the upper mold 60 positioned on the lower surface of the upper plate 50 is closely contacted with the lower mold 30 while the lower plate 40 is moved down together with the auxiliary lift plate 42. At the same time, (S) to be elastically pressed.

9, when the auxiliary lifting plate 42 of the lower plate 40 is independently lowered using the lifting unit 43, only the lifting rod 42A is lowered, The lower end of the sprue 111 is inserted into the through hole 61 of the upper mold 60 while the sprue 111 installed on the upper steel plate 110 is lowered.

When the lower end of the sprue 111 is inserted into the upper mold 60, the lower mold 30 and the upper mold 60 are pushed along the sprue 111 by pouring molten metal into the sprue 111 using a separately provided robot or the like, A certain amount of the molten metal is injected into the inner space between the inner and outer walls.

When the molten metal is injected as described above, only the auxiliary lifting plate 42 is lifted independently again to lift the lifting plate 110 from the upper mold 60 and power is supplied to the motor M So that the product is cast while rotating the main shaft 20 to rotate the lower mold 30 and the upper mold 60 at an appropriate speed.

At this time, the lower mold 30 and the upper mold 60 are heated to an appropriate temperature by the inner heating devices 80A and 80B, and the casting is performed while the molten metal is maintained at a high temperature. The blowing fan 100 is operated to supply the cooling air to the air holes H of the lower mold 30 and the upper mold 60 so that the shape of the molded product It is cooled rapidly while being maintained, and a fine quality product is cast.

10, the upper plate 50 is lifted up by moving the lower plate 40 upward, thereby separating the upper mold 60 closely attached to the lower mold 30, At the same time, the ejector 70 located on the bottom surface of the lower mold 30 is raised, and the casting of the product is completed while discharging the cast product from the lower mold 30.
That is, when the lower plate 40 is lifted and lowered by the lifting device, the upper plate 50 and the upper mold 60 are integrally lifted and lowered together. When the upper mold is lowered and the upper and lower molds are engaged, The mold is rotated, the product is ejected when the upper mold is lifted, and the upper and lower molds are integrally rotated by the rotation of the main shaft 20 when the upper and lower molds are engaged to perform centrifugal casting.

As described above, the present invention is a centrifugal casting apparatus for casting a product using a centrifugal casting method, in which a state in which the upper and lower molds are tightly adhered to each other is maintained as it is, Defects are prevented.

According to the present invention, the power can be supplied to the upper and lower molds through the main spindle to be rotated. In this way, the upper and lower molds are heated so that the molten metal can sufficiently flow into the molds, So that the shape thereof can be maintained at a high speed, whereby a compact product is cast.

10: main frame 11: bottom plate
12: top plate 13: support
20: main shaft 21:
30: lower mold 40: lower plate
41: main lifting plate 41A: first lifting device
41A ': load 41B: second elevating device
42: auxiliary lift plate 42A: lift rod
43: lift unit 43A: cylinder
43B: rod 50: upper plate
60: upper mold 61: through hole
70: Ejector 80A, 80B: Heating device
90: Power supply unit 91: Energizing plate
100: blowing fan 101: blowing pipe
110: steel plate 111: sprue
B: Bearing unit B1: Upper bearing part
B2: Lower bearing part B3: Roller
H: Air hole PL1, PL2: Contact plate
M: Motor RG: Reducer
S: Pressure spring

Claims (4)

A main frame (10) having a frame structure extending vertically;
A main shaft 20 installed through the center of the main frame 10 and rotated by a motor M;
A lower mold (30) supported by the upper plate (12) fixed to the main frame (10) and rotated by the main shaft (20);
A lower plate 40 installed on the inner side of the main frame 10 and operated to move up and down;
An upper plate 50 mounted on the upper mold 30 and operated to move up and down by the lower plate 40;
An upper mold 60 rotatably installed on a bottom surface of the upper plate 50 and closely contacting the lower mold 30 by a lowering operation of the upper plate 50;
And an ejector (70) disposed below the lower mold (30) and discharging the product cast by the elevating operation from the lower mold (30)

When the lower plate 40 is lifted and lowered by the lifting device, the upper plate 50 and the upper mold 60 are integrally lifted and lowered together. When the upper mold is lowered and the upper and lower molds are engaged, When the upper and lower molds are engaged with each other, the upper and lower molds are integrally rotated by the rotation of the main shaft 20 to perform centrifugal casting,

The lower plate (40)
A main lifting plate 41 which is vertically movable at a lower position of the upper plate 12 fixed to the main frame 10;
A first elevating device (41A) supported by the main frame (10) to move the main lifting plate (41) up and down;
And a second elevating device 41B having both ends thereof coupled to the main lifting plate 41 and the upper plate 50 and for lifting and lowering the upper plate 50 by lifting and lowering the main lifting steel plate 41 ,

A heating device 80A or 80B for heating the lower mold 30 and the upper mold 60 by applying power to the inside of the lower mold 30 and the upper mold 60 is further provided And a rotary mold heating means for rotating the casting mold. The method according to claim 1,
The cylindrical main body (20) is provided with a cylindrical main body (21) so as to surround the outer peripheral surface of the main shaft (20)
A power supply unit 90 for supplying power to the power supply plate 91 and a power supply plate 91 for contacting the power supply unit 21 are provided on a side surface of the power supply unit 21,
The lower mold 30 and the upper mold 60 are provided with contact plates PL1 and PL2 so as to face each other around the outer periphery of the lower mold 30 and the upper mold 60, 80A, and 80B of the rotary mold heating unit.
The method according to claim 1,
And a blowing fan (100) installed in the main frame (10) for supplying cooling air along the outer peripheral surfaces of the lower mold (30) and the upper mold (60) Wherein
The method of claim 3,
A plurality of air holes (H) are radially formed on the lower side of the lower mold (30) and the upper side of the upper mold (60)
Wherein the cooling air is supplied from the blowing fan (100) to the air hole (H) of the lower mold (30).

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