JP2021016943A - Mold and molding apparatus - Google Patents

Abstract

To provide a mold and a molding apparatus capable of securing both heating speed and cooling speed of a molding surface.SOLUTION: Molds 20 and 21 are provided with: (A) mold bodies 31 and 34 having molding surfaces 20A and 21A comprising a magnetic metal for molding a surface of a molded article 12; (B) cooling channels 40 and 42 penetrated and formed in the mold bodies 31 and 34, for making a coolant flow therethrough; and (C) electric conductors 70 and 71 arranged along the cooling channels 40 and 42 in a state of being separated from an inner surface inside the cooling channels 40 and 42, for inducing current into the mold bodies 31 and 34 by means of a magnetic field generated by current when it is flowed to the electric conductors.SELECTED DRAWING: Figure 2

Description

The present invention relates to a molding die and to a molding apparatus including the molding die.

The molding die described in Patent Document 1 below is arranged on a magnetic metal portion having a molding surface (cavity surface) for forming a surface of a molded product and on the outside (opposite side of the molding surface) of the magnetic metal portion. It is composed of an induction coil holding portion made of an insulating resin and a non-magnetic metal portion arranged on the outside of the induction coil holding portion. Then, in the molding die described in Patent Document 1 below, an induction coil for heating the magnetic metal portion by generating an induced current in the magnetic metal portion by passing an electric current is arranged in the induction coil holding portion. At the same time, a through hole for water cooling for cooling the magnetic metal portion is formed in the magnetic metal portion.

Japanese Patent No. 6040546

In the molding die described in Patent Document 1, since an induction coil for heating the magnetic metal portion is arranged in an insulating resin arranged outside the magnetic metal portion having a molding surface, the molding surface is formed from the induction coil. There is a problem that the distance to the molded surface is relatively long and the heating rate of the molded surface becomes slow. Furthermore, since the through holes for cooling and the induction coils for heating are arranged side by side in this order from the molding surface to the outside, it is difficult to bring the induction coils closer to the molding surface. Contrary to the molding die described in Patent Document 1, the molding die may be arranged in the order of the heating induction coil and the cooling through hole from the molding surface to the outside, but also through the cooling. Since the holes move away from the molded surface, the cooling rate of the molded surface becomes slow.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a molding die and a molding apparatus capable of ensuring both a heating rate and a cooling rate of a molded surface.

In order to solve the above problems, the molding die of the present invention
A molding die body made of magnetic metal and having a molding surface for molding the surface of the molded product,
A cooling path that is formed through the molding body to allow the refrigerant to flow,
A conductor that is arranged inside the cooling path along the cooling path in a state of being separated from the inner surface and for inducing a current to the molding body by a magnetic field generated by the current flowing through the cooling path.
It is characterized by being equipped with.

The molding die having this configuration is arranged in the cooling path so that the conductor does not come into contact with the inner surface thereof, and is insulated from the forming die body made of magnetic metal, and an electric current flows through the conductor. As a result, the vicinity of the inner surface of the cooling path in the mold body is induced and heated by the induced current generated in the mold body. That is, in the molding die having this configuration, by bringing the cooling path closer to the molding surface, not only the cooled portion in the molding die main body but also the heated portion can be brought closer to the molding surface. Therefore, according to the molding die having this configuration, both the heating rate and the cooling rate of the molded surface can be secured, and the molded surface can be rapidly cooled and heated. The "cooling path" in the molding die having this configuration is specifically a through hole formed in the molding die main body, and either a liquid or a gas can be adopted as the refrigerant.

In the above configuration, the conductor may have a tubular shape so that a refrigerant can flow inside.

When an electric current is passed through the conductor, it also generates heat by induction heating. In the molding mold having this configuration, heat generation of the conductor can be suppressed by flowing a refrigerant inside the conductor. Therefore, according to the molding die having this configuration, by suppressing the heat generation of the conductor, when changing from the step of heating the molded surface to the step of cooling, the molding die main body is cooled by the refrigerant flowing outside the conductor. This can be done efficiently and the cooling rate of the molded surface can be improved. Further, by suppressing the heat generation of the conductor, the durability of the conductor can be improved.

Further, in the above configuration, in addition to the first cooling passage which is the cooling passage, a second cooling passage which is formed through the molding main body to allow the refrigerant to flow is further provided, and the second cooling passage is provided. , The configuration can be formed at a position separated from the molding surface as compared with the first cooling path.

Since the molding die having this configuration is provided with the second cooling path on the outside of the first cooling path (on the side opposite to the molding surface), the molding die main body can be efficiently cooled, and the molding surface can be cooled. The cooling rate can be improved.

Further, in order to solve the above problems, the molding apparatus of the present invention can be used.
A molding mold having the above configuration and a conductor that is tubular and allows the refrigerant to flow inside.
A current supply unit that supplies current to the conductor and
A refrigerant supply unit that supplies refrigerant to each of the cooling path and the cooling path inside the conductor, which is a cooling path formed inside the conductor.
Consists of including
The refrigerant supply unit can independently supply the refrigerant to each of the cooling path and the conductive body cooling path, and when cooling the mold main body, the cooling path and the conductive body cooling path When a refrigerant is supplied to both of them and a current is supplied to the conductor by the current supply unit to heat the mold main body, the refrigerant is not supplied to the cooling path but is supplied to the conductor cooling path. It is characterized by being configured to do so.

The molding apparatus having this configuration is premised on a molding device including a molding mold capable of flowing a refrigerant into the conductor, and the inside of the conductor is not only when the molding surface is cooled but also when it is heated. It is configured to constantly circulate the refrigerant. Therefore, the molding apparatus having this configuration can efficiently suppress heat generation of the conductor when the molded surface is heated, improve the cooling rate of the molded surface, and improve the durability of the conductor.

According to the present invention, it is possible to provide a molding die and a molding apparatus capable of ensuring both a heating rate and a cooling rate of a molded surface.

It is a top view which shows typically the injection molding apparatus which is an Example of this invention. It is a side sectional view of the injection molding apparatus which is an Example of this invention. FIG. 5 is an enlarged cross-sectional view showing a mold according to an embodiment of the present invention shown in FIG. FIG. 3 is a diagram showing a state of the molded surface when heated. FIG. 3 is a diagram showing a state when the molded surface is cooled.

Hereinafter, examples of the present invention will be described in detail as embodiments for carrying out the present invention with reference to the drawings. The present invention is not limited to the following examples, and can be carried out in various embodiments with various modifications and improvements based on the knowledge of those skilled in the art.

The injection molding apparatus 10 (hereinafter, may be simply referred to as “molding apparatus 10”) as the molding apparatus according to the embodiment of the present invention is schematically shown in FIGS. 1 and 2. The molding apparatus 10 is an apparatus for manufacturing a trim board 12 made of a synthetic resin (for example, a thermoplastic resin such as polypropylene) which is a resin molded product by injection molding. As shown in FIGS. 1 and 2, the molding apparatus 10 is mainly composed of a pair of dies 20 and 21 which are molding dies of the present embodiment arranged in a state of facing each other in the vertical direction. ..

Of the pair of molds 20 and 21, the mold 20 located above is a fixed mold provided fixedly, and the mold 21 located below is a movable mold that can be moved in the vertical direction by a driving device. is there. The fixed mold 20 is formed on the lower surface side with a molding surface 20A that imitates one of the front and back surfaces of the trim board 12, and the movable mold 21 is formed on the upper surface side of the front and back surfaces of the trim board 12. A molded surface 21A that follows the other surface is formed. In the state where the molds 20 and 21 are closed (the movable mold 21 is positioned upward), as shown in FIG. 2, the trim board 12 is formed between the molding surface 20A and the molding surface 21A. A molding space is formed.

The molding device 10 is configured to pour the molten resin into the molding space by an injection device arranged on the fixed mold 20 side. Further, the molding device 10 includes an extrusion device 22 for extruding the trim board 12, which is a molded product, from the movable mold 21. The extruder 22 is configured to include an ejector plate 23 and a plurality of ejector pins 24 so that when the movable mold 21 is lowered, the plate holding pin 25 restricts the downward movement of the ejector plate 23. It is configured. That is, the extruder 22 moves the ejector plate 23 relative to the movable mold 21 to project the ejector pin 24 from the molding surface 21A of the movable mold 21, thereby pushing the trim board 12 out of the movable mold 21. It has become.

The fixed mold 20 includes a fixed side mounting plate 30 made of a non-magnetic material, a mold main body (molding mold main body) 31 made of a magnetic metal (for example, iron) fixed to the lower surface side of the fixed side mounting plate 30. Is configured as the main body and composition. Further, the movable mold 21 is also a mold made of a movable side mounting plate 32 made of a non-magnetic material and a magnetic metal fixed above the movable side mounting plate 32 via a spacer block 33, similarly to the fixed mold 20. It is mainly composed of a main body (molding mold main body) 34. The mold body 31 of the fixed mold 20 has the above-mentioned molding surface 20A on the lower surface side, and the mold body 34 of the movable mold 21 has the above-mentioned molding surface 21A on the upper surface side. Although the fixed side mounting plate 30 and the movable side mounting plate 32 are molded of a non-magnetic material in this embodiment, they may be molded of a magnetic material.

Then, in the mold main body 31 of the fixed mold 20, a plurality of first through holes 40 (8 in this embodiment) extending in parallel with the molding surface 20A are formed in the vicinity of the molding surface 20A, and they are formed. A plurality of second through holes 41 (in this embodiment, the same number of eight as the first through holes 40) are formed above the plurality of first through holes 40 so as to extend in parallel with the first through holes 40. Further, the mold body 34 of the movable mold 21 is formed with a plurality of first through holes 42 extending in parallel with the molding surface 20A in the vicinity of the molding surface 21A, similarly to the mold body 31 of the fixed mold 20. A plurality of second through holes 43 extending in parallel with the through holes 42 are formed above the plurality of through holes 42.

The molding device 10 includes a heating device 50 for heating the molding surface 20A and the molding surface 21A, and a cooling device 51 for cooling the molding surface 20A and the molding surface 21A. First, the cooling device 51 will be described. The cooling device 51 is configured to cool and circulate water as a refrigerant, and as schematically shown in FIG. 1, the cooling water circulation device 61 circulates cooling water in the circulation path 60 and the circulation path 60. And consists of.

The circulation path 60 includes a supply hose 62 that supplies the water cooled by the cooling water circulation device 61 to each of the pair of molds 20 and 21, and a cooling water circulation device 61 that supplies water discharged from each of the pair of molds 20 and 21. It is configured to include a discharge hose 63 for returning to. The supply hose 62 has a plurality of branches on one end side (downstream side), and the first through hole 40 and the second through hole 41 formed in the mold main body 31 of the fixed mold 20 and the movable mold 21. It is connected to the opening on one end side of the first through hole 42 and the second through hole 43 formed in the mold main body 34 of the above. On the other hand, the discharge hose 63 has a plurality of branches on one end side (upstream side), and the first through hole 40 and the second through hole 41 formed in the mold main body 31 of the fixed mold 20 and the movable mold 21. It is connected to the opening on the other end side of the first through hole 42 and the second through hole 43 formed in the mold main body 34 of the above. That is, the first through hole 40 and the second through hole 41 formed in the mold main body 31 of the fixed mold 20 and the first through hole 42 and the second through hole 43 formed in the mold main body 34 of the movable mold 21. Is a part of the circulation path 60, and functions as a cooling path through which cooling water as a refrigerant is circulated in order to cool the molded surfaces 20A and 21A.

Next, the heating device 50 will be described. The heating device 50 is configured to heat the molded surfaces 20A and 21A by heating the mold bodies 31 and 34 made of magnetic metal by using induction heating. Specifically, as shown in FIGS. 1 and 2, the heating device 50 includes copper pipes 70 and 71 as conductors and a high-frequency power source as a current supply unit that supplies high-frequency current to the copper pipes 70 and 71. 72 and. The outer diameter of each of the copper pipes 70 and 71 is smaller than the inner diameter of the first through holes 40 and 42, and one of the copper pipes 70 is inserted through the plurality of first through holes 40 of the fixed mold 20. The other copper pipe 71 is extended so as to insert a plurality of first through holes 42 of the fixed mold 20. Incidentally, as shown in FIG. 3, spacers 73 made of insulating resin are arranged between the copper pipes 70 and 71 and the first through holes 40 and 42 at predetermined intervals in the extending direction. The copper pipes 70 and 71 are separated from the inner surfaces of the first through holes 40 and 42. That is, the copper pipes 70 and 71 and the first through holes 40 and 42 are in an insulated state.

Further, in the heating device 50, copper pipes 70 and 71, which are conductors, are tubular, and water as a refrigerant can be circulated inside the tubular pipes 70 and 71. Specifically, the heating device 50 is configured to include a cooling water circulation device 74 having the same configuration as the cooling water circulation device 61 described above in order to suppress heat generation of the copper pipes 70 and 71, and the inside of the copper pipes 70 and 71. Is configured to function as a circulation path, and the cooling water circulation device 74 circulates the cooled water in the copper pipes 70 and 71. The cooling water circulation device 74 is integrally configured with the high frequency power supply 72 and unitized to form an induction heating power supply unit 75.

From the above configuration, in the molding apparatus 10 of the present embodiment, the gap between the inner peripheral surfaces of the first through holes 40 and 42 and the outer peripheral surfaces of the copper pipes 70 and 71 functions as the first cooling passage P1. The second through holes 41 and 43 function as the second cooling passages P2 formed at positions separated from the molding surfaces 20A and 21A as compared with the first cooling passages. Further, in the present embodiment, the molding apparatus 10 has a configuration in which a refrigerant can flow inside the copper pipes 70 and 71 which are conductors, and has a cooling path P3 inside the conductor. In the molding apparatus 10 of the present embodiment, the cooling water circulation device 61 that circulates the refrigerant in the first cooling passage P1 and the second cooling passage P2 and the cooling water circulation device 74 that circulates the refrigerant in the conductive body cooling passage P3. Each of them functions as a refrigerant supply unit that supplies a refrigerant to the cooling path. That is, the molding apparatus 10 of this embodiment can supply the refrigerant to the conductive body cooling passage P3 independently of the first cooling passage P1 and the second cooling passage P2.

Next, a method of heating / cooling the molding surfaces 20A and 21A in the molding apparatus 10 of the present embodiment configured as described above will be described. First, the case of heating the molded surfaces 20A and 21A will be described on behalf of the fixed mold 20 with reference to FIG. When heating the molded surface 20A, a current is supplied to the copper pipe 70 by the high frequency power supply 72. As a result, a magnetic field is formed around the copper pipe 70, and the magnetic field generates an induced current (eddy current) in the vicinity of the inner peripheral surface of the first through hole 40 in the mold body 31. Then, the mold main body 31 generates heat in the vicinity of the inner peripheral surface of the first through hole 40 due to the electric resistance to the induced current, and the heat is transmitted in the mold main body 31 to heat the molding surface 20A. When the electric current is supplied to the copper pipe 70, the cooling water circulation device 61 is stopped, and the cooling water is not supplied to the first cooling passage P1 and the second cooling passage P2. On the other hand, the cooling water circulation device 74 included in the induction heating power supply unit 75 is operated, and the cooling water is supplied to the cooling path P3 in the conductive body. The heating method of the molded surfaces 20A and 21A by this induction heating has a very high heating rate as compared with the heating using a heater, and the molded surfaces 20A and 21A can be heated rapidly.

On the other hand, the case of cooling the molded surfaces 20A and 21A will be described in detail with reference to FIG. 5 (shown on behalf of the fixed mold 20). When the heating state for heating the molding surfaces 20A and 21A is switched to the cooling state for cooling them, the high frequency power supply 72 is stopped and the cooling water circulation device 61 is operated in the present molding apparatus 10. Cooling water is supplied to the first cooling passage P1 and the second cooling passage P2. Even in the cooled state, the cooling water circulation device 74 included in the induction heating power supply unit 75 is operated, and cooling water is supplied to the cooling path P3 in the conductive body. That is, cooling water is constantly supplied to the conductive body cooling path P3 regardless of the heating state or the cooling state.

As described above, in each of the pair of dies 20 and 21 which are the molding dies of this embodiment, copper pipes 70 and 71 which are conductors are arranged in the first through holes 40 and 42 which are the first cooling paths. Therefore, the vicinity of the inner peripheral surfaces of the first through holes 40 and 42 is defined as a portion heated by the heating device 50 and also as a portion cooled by the cooling device 51. That is, in each of the molds 20 and 21, both the heating portion by the heating device 50 and the cooling portion by the cooling device 51 are set in the vicinity of the molding surfaces 20A and 21A. That is, the molds 20 and 21 can secure both the heating rate and the cooling rate of the molded surfaces 20A and 21A. That is, the molding apparatus 10 of the present embodiment is capable of rapidly heating and rapidly cooling the molding surfaces 20A and 21A.

Further, when an electric current is supplied to the copper pipes 70 and 71 which are conductors, the copper pipes 70 and 71 themselves also generate heat due to induction heating. However, in the molding apparatus 10 of the present embodiment, since the copper pipes 70 and 71 are provided with cooling passages P3 inside and cooling water is supplied at the time of heating, heat generation due to induction heating can be suppressed. Therefore, the molding apparatus 10 of this embodiment can rapidly cool the molding surfaces 20A and 21A even when switching from the heating state to the cooling state. Furthermore, in the molding apparatus 10 of the present embodiment, the copper pipes 70 and 71, which are conductors, are arranged in the first through holes 40 and 42, so that the first penetration is created in the mold main bodies 31 and 34. A second cooling path P2 is provided in a space outside the holes 40 and 42 (opposite to the molding surfaces 20A and 21A). Therefore, in the molding apparatus 10 of this embodiment, the cooling rates of the molding surfaces 20A and 21A are higher due to the second cooling passage P2. Incidentally, the copper pipes 70 and 71 are improved in durability because heat generation due to induction heating is suppressed by the above-mentioned conductive body cooling passage P3.

The molding apparatus 10 of the present embodiment and the molding molds 20 and 21 of the present embodiment are the injection molding apparatus and the molding mold of the injection molding apparatus, but the molding apparatus and the molding of the present invention are not limited thereto. The mold can also be used for a press molding apparatus and a molding die of the press molding apparatus. Further, in this embodiment, the refrigerant is water, but it may be air. In this embodiment, the molded surface has a flat shape, but it may have a concave-convex shape. In that case, for example, a plurality of cooling passages (first cooling passages) may be provided along the molding surface, in other words, each cooling passage may be provided so that the distances from the molding surface are equal.

10 ... Injection molding device [molding device], 12 ... Trim board [molded product], 20 ... Mold (fixed mold) [molding mold], 21 ... Mold (movable mold) [molding mold], 31 ... Mold body [Molding mold main body], 34 ... Mold main body [Molding mold main body], 40 ... 1st through hole, 41 ... 2nd through hole, 42 ... 1st through hole, 43 ... 2nd through hole, 50 ... Heating device, 51 ... Cooling device, 61 ... Cooling water circulation device [Fluent supply unit], 70, 71 ... Copper pipe [Conductor], 72 ... High frequency power supply [Current supply unit], 73 ... Spacer, 74 ... Cooling water circulation device [Fluent supply unit] ], P1 ... 1st cooling path, P2 ... 2nd cooling path, P3 ... Conductive body cooling path

Claims (4)

A molding die body made of magnetic metal and having a molding surface for molding the surface of the molded product,
A cooling path that is formed through the molding body to allow the refrigerant to flow,
A conductor arranged inside the cooling path along the cooling path in a state of being separated from the inner surface, and for inducing a current to the molding body by a magnetic field generated when a current is passed through the cooling path.
Mold with. The molding die according to claim 1, wherein the conductor has a tubular shape, and a refrigerant can be circulated inside. In addition to the first cooling path, which is the cooling path, a second cooling path is further provided through the molding body to allow the refrigerant to flow.
The molding die according to claim 1 or 2, wherein the second cooling passage is formed at a position separated from the molding surface as compared with the first cooling passage. The molding mold according to claim 2 and
A current supply unit that supplies current to the conductor,
A refrigerant supply unit that supplies refrigerant to each of the cooling path and the cooling path inside the conductor, which is a cooling path formed inside the conductor.
Consists of including
The refrigerant supply unit can independently supply the refrigerant to each of the cooling path and the conductive body cooling path, and when cooling the mold main body, the cooling path and the conductive body cooling path When a refrigerant is supplied to both of them and a current is supplied to the conductor by the current supply unit to heat the mold main body, the refrigerant is not supplied to the cooling path but is supplied to the conductor cooling path. A molding device configured to do so.

Images