JP2018032729A - Method for manufacturing heat sink - Google Patents

Abstract

A heat sink manufacturing method capable of forming a thermally radiating paint film on the surface of a rough material without requiring a large amount of heat energy is provided. A heat sink manufacturing method for manufacturing a heat sink comprising a rough material W and a heat emitting paint film formed on the surface of the rough material W, wherein a core 3 is accommodated in a cavity C of a mold 10. Then, the first step of injecting the molten metal into the cavity C to cast the box-shaped rough material W containing the core 3 inside, the coating area of the box-shaped rough material W containing the core 3 inside , and a thermally emissive coating is applied to the surface of the rough material W in the coating area to form a thermally emissive coating, thereby manufacturing a heat sink. [Selection drawing] Fig. 1

Description

  The present invention relates to a heat sink manufacturing method for manufacturing a heat sink composed of a rough material and a thermal radiation coating film formed on the surface of the rough material.

  Since recent electric circuits have been downsized and the heat generation density has increased with the downsizing, improvement of the heat dissipation performance of the electric circuit is one of the important development factors.

  In general, an electric circuit having a large calorific value is manufactured by aluminum die casting, and a metal housing has a high heat conductivity but a low heat transfer rate to air. For example, while aluminum has a thermal conductivity of 100 W / mK, its heat transfer coefficient (emissivity) to air is as low as about 0.1 to 0.3.

  Therefore, attempts have been made to form a film made of carbon, nitride, resin, or the like, which is a substance having a high heat transfer coefficient to the air, on the surface of a metal casing.

  Here, Patent Document 1 includes ceramic powder having an average particle diameter of 0.1 to 50 μm and containing zinc oxide powder and / or titanium oxide powder, and a binder, and ceramic powder with respect to 100 parts by mass of the binder component. A heat sink is disclosed in which a heat-radiating paint containing 25 to 100 parts by mass of a component is applied with an average film thickness of 1 to 50 μm.

JP 2012-246365 A

  According to the heat sink described in Patent Document 1, the emissivity in the infrared region is increased by having a film made of a heat-radiating paint, and heat can be efficiently radiated.

  By the way, in the manufacture of the heat sink, after casting a rough material with a molding die, the coarse material is taken out from the molding die, the coarse material is transported to a predetermined application area, and the above-described heat radiation paint is applied to the surface of the rough material. Then, the thermal radiation coating film is formed by baking or volatilization of the solvent to produce the coating.

  However, there is a problem that the temperature of the coarse material is lowered in the process of being taken out from the mold and conveyed and lowered to a temperature lower than the temperature suitable for applying the coating material. Another problem is that the temperature of the coarse material drops to a temperature lower than the temperature suitable for applying the paint during spray coating of the coarse material.

  When the raw material whose temperature has been lowered is placed in a firing furnace and the thermal radiation paint is baked or the solvent is volatilized, the temperature of the coarse material is raised to a temperature suitable for applying the paint, and the paint is further baked or the solvent is evaporated. Therefore, a great deal of heat energy is required.

  The present invention has been made in view of the above-described problems, and relates to a method of manufacturing a heat sink by forming a rough material with a mold and forming a heat-radiating paint film on the surface of the rough material. It is an object of the present invention to provide a method of manufacturing a heat sink that can form a heat-radiating paint film on the surface of a rough material while making it unnecessary.

  In order to achieve the above object, a heat sink manufacturing method according to the present invention is a heat sink manufacturing method for manufacturing a heat sink comprising a rough material and a heat-radiating paint film formed on the surface of the rough material. A first step of housing a core in the cavity, injecting a molten metal into the cavity, and casting a box-shaped coarse material containing the core inside, a box type containing the core inside The coarse material is transported to a coating area, and a thermal radiation coating film is formed on the surface of the coarse material by applying a thermal radiation paint film to the coating area, thereby producing a heat sink. .

  In the heat sink manufacturing method of the present invention, a molten metal is poured in a state where the core is accommodated in the cavity of the molding die, and a box-shaped coarse material including the core is cast therein, and the core is included therein. By transporting the raw material in the state to the application area and applying the thermal radiation paint, the heat stored in the heat capacity of the core is transferred to the raw material, and the temperature drop of the raw material can be suppressed. Thus, it is possible to apply the heat-radiating paint to the rough material at a temperature suitable for the application of the paint while eliminating a great deal of heat energy.

  For example, since the heat of the molten aluminum melt is about 700 ° C., the core in the cavity is heated and stored at the temperature of the molten metal injected into the cavity.

  In the cavity, a box-shaped coarse material is cast (molded) so as to surround the core. Here, the “box shape” is not limited to a specific shape, but means an arbitrary shape that accommodates the core therein, and therefore, the coarse material depends on the shape of the cavity and the shape of the core. Is determined. As a general shape, for example, a box shape in which one wide surface is opened by a rectangular parallelepiped having two wide surfaces can be cited.

  In applying the heat-radiating paint to the surface of the box-shaped rough material in the application area, it is not necessary to apply the heat-radiating paint inside the box-shaped rough material in the conventional manufacturing method. It was necessary to apply the paint after masking the inside. On the other hand, in the manufacturing method of the present invention, the core is accommodated inside the box-shaped coarse material, and the inside of the coarse material is protected by this core. There is no need to do this.

  Further, when forming a box-shaped rough material by a conventional manufacturing method, when the mold is composed of two molds, a first mold and a second mold, a convex portion is formed on the cavity surface of one second mold. It was necessary to provide a concave portion in which the convex portion was loosely fitted on the cavity surface of the other first mold. On the other hand, in the manufacturing method of the present invention, for example, a rectangular parallelepiped core is accommodated in the cavity, so that the core plays the role of the inner mold of the box-shaped coarse material. There is no need to provide a protrusion on the surface. Therefore, since the shape of the second mold can be a simple shape that does not have a convex portion, the production cost of the mold is reduced.

  Furthermore, when applying a heat-radiating paint to the surface of a rough material by a conventional manufacturing method, the rough material whose temperature has decreased during the process of demolding and transporting is placed on a jig with a built-in heater, for example, and heated to apply the paint. It was necessary to raise the temperature of the crude material to a temperature suitable for the temperature. However, a jig with a built-in heater is expensive to manufacture, and as described above, this method requires a large amount of heat energy. In contrast, in the manufacturing method of the present invention, the heat stored in the heat capacity of the core is transferred to the coarse material and the temperature drop of the coarse material can be suppressed. It can be made unnecessary, and a great deal of heat energy for raising the temperature of the coarse material can also be made unnecessary.

  In addition, since the thermal radiation coating is applied to the coarse material heated by the core, the thermal radiation paint can be baked and the solvent can be volatilized by the heat of the coarse material. The firing furnace required in the volatilization process can be dispensed with, and the baking process and the solvent volatilization process can be dispensed with, thereby increasing the production efficiency.

  As can be understood from the above description, according to the heat sink manufacturing method of the present invention, a box-shaped coarse material in which a molten metal is injected in a state in which the core is accommodated in the cavity of the molding die and the core is contained therein. The heat accumulated in the heat capacity of the core is transferred to the rough material by transporting the rough material with the core inside to the application area and applying the thermal radiation paint. It is possible to suppress the temperature drop of the coarse material, and thus it is possible to form a heat-radiating paint film on the surface of the coarse material without requiring a great amount of heat energy.

It is the schematic diagram which showed embodiment of the manufacturing system applied with the manufacturing method of the heat sink of this invention. It is the schematic diagram explaining the 1st step of the manufacturing method of the heat sink of this invention. It is the schematic diagram explaining the 2nd step of the manufacturing method of the heat sink of this invention.

  Embodiments of a heat sink manufacturing method of the present invention will be described below together with a manufacturing system with reference to the drawings.

(Heatsink manufacturing system)
FIG. 1 is a schematic view showing an embodiment of a heat sink manufacturing system of the present invention. The manufacturing system 300 shown in the figure includes a casting apparatus 100 and a coating apparatus 200.

  The casting apparatus 100 includes a molding die 10, a molten metal holding furnace 20 that holds molten metal provided to the molding die 10, and a molten metal supply pipe 30 that provides molten metal from the molten metal holding furnace 20 to the molding die 10. .

  The molding die 10 is composed of a first die 1 and a second die 2, and a concave portion 1a is formed in the first die 1. The second die 2 is a simple rectangular parallelepiped die.

  In closing the mold 10, the core 3 is accommodated in the recess 1 a of the first mold 1 in the formed cavity. The dimension of the core 3 is smaller than the dimension of the recess 1a, and the core 3 is positioned so as to contact the second mold 2 at the center position of the recess 1a, so that the space between the core 3 and the wall surface of the recess 1a is located. The molten metal is poured.

  The molten metal holding furnace 20 contains molten metal such as molten aluminum. In the case of molten aluminum, the internal temperature is about 700 ° C.

  On the other hand, the coating apparatus 200 includes a paint container 40 that contains a heat-radiating paint, a spray nozzle 50, and a paint supply pipe 40A that provides the heat-radiating paint from the paint container 40 to the spray nozzle 50. .

  Here, examples of the heat-radiating paint include polyamideimide (PAI), epoxy paint, and phenol paint.

  Next, a heat sink manufacturing method using the manufacturing system 300 shown in FIG. 1 will be described below.

(Production method of heat sink)
2 and 3 are schematic views illustrating the first step and the second step of the heat sink manufacturing method of the present invention, respectively.

  First, after applying a release agent to the wall surface of the cavity C of the mold 10, the core 3 is accommodated inside the mold 10 and closed as shown in FIG. Further, the core 3 is positioned in the recess 1 a of the first mold 1.

  A molten metal is supplied from the molten metal holding furnace 20 to the cavity C of the mold 10 that is closed (X direction), and a coarse material is cast in the cavity C.

  The molten metal poured into the cavity C flows into the space between the core 3 and the wall surface of the recess 1a, and in addition to the forming of the coarse material accompanying the hardening of the molten metal, the core 3 is heated by the heat of the molten metal. (First step).

  Next, as shown in FIG. 3, when the molten metal is solidified to form the coarse material W, the molding die 10 is opened to take out the coarse material W and transport it to the application region.

  Here, the removed rough material W has a rectangular parallelepiped box shape, and the core 3 is accommodated therein.

  In the process of taking out the coarse material W from the mold 10 and transporting it to the application region, the temperature of the coarse material W is usually lowered, and in some cases, the temperature is lowered to a temperature lower than the temperature suitable for coating.

  However, in the manufacturing method shown in the figure, since the core 3 heated by the heat of the molten metal is accommodated in the box-shaped coarse material W, the coarse material W is transferred by heat transfer from the core 3 (Z direction). In this transport process, the temperature is prevented from greatly decreasing.

  At the stage where the coarse material W reaches a temperature suitable for coating, the thermal radiation paint is ejected from the spray nozzle 50 to the coarse material W (Y direction) and applied to the surface of the coarse material W (second Step).

  In this way, since the temperature of the coarse material W is suppressed from being lowered to a temperature lower than the temperature suitable for coating application by the heat from the core 3, the coarse material having been lowered to a temperature lower than the temperature suitable for coating application. The coating of the coarse material W can be realized while eliminating the great heat energy required to raise the temperature of the material.

  Further, the heat of the coarse material W can be used to bake the heat-radiating paint applied on the surface of the coarse material W and to volatilize the solvent. In this case, the baking furnace required in the conventional baking process and the solvent volatilization process becomes unnecessary, and the baking process and the solvent volatilization process become unnecessary, so the production cost of the manufacturing system can be reduced. In addition, the manufacturing efficiency of the heat sink can be significantly improved.

  In addition, in applying the heat-radiating paint on the surface of the box-shaped coarse material W in the application region, in the conventional manufacturing method, it is not necessary to apply the heat-radiating paint to the inside of the box-shaped rough material. It was necessary to apply the paint after masking the inside of the rough material. In contrast, in the illustrated manufacturing method, the core 3 is accommodated inside the box-shaped coarse material W, and the interior of the coarse material W is protected by the core 3, so that the coarse material W is applied during coating. No need to mask inside.

  Furthermore, when forming a box-shaped rough material by a conventional manufacturing method, when the mold is composed of two molds, a first mold and a second mold, a convex portion is formed on the cavity surface of one second mold. It was necessary to provide a concave portion in which the convex portion was loosely fitted on the cavity surface of the other first mold. On the other hand, in the illustrated manufacturing method, for example, the rectangular core 3 is accommodated in the cavity C so that the core 3 serves as a mold inside the box-shaped coarse material W. There is no need to provide a convex portion on the cavity surface. Therefore, since the shape of the 2nd type | mold 2 can be made into the simple shape which does not comprise a convex part, the manufacturing cost of the shaping | molding die 10 can also be reduced.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... 1st type | mold, 2 ... 2nd type | mold, 1a ... Recessed part, 3 ... Core, 10 ... Molding die, 20 ... Molten metal holding furnace, 30 ... Molten metal supply pipe | tube, 40 ... Paint container, 50 ... Spray nozzle, 100 ... Casting device, 200 ... Coating device, 300 ... (heat sink) manufacturing system, C ... Cavity, W ... Rough material

Claims (1)

A heat sink manufacturing method for manufacturing a heat sink comprising a rough material and a heat radiation coating film formed on the surface of the rough material,
A first step of housing a core in a cavity of a molding die, injecting a molten metal into the cavity, and casting a box-shaped coarse material containing the core inside;
The box-shaped rough material containing the core is transported to the coating area, and a heat-radiating paint film is formed on the surface of the rough material to form a heat-radiating paint film, thereby manufacturing a heat sink. A heat sink manufacturing method comprising a second step.

Images