Manufacturing method of copper-aluminum composite heat dissipation plate and copper-aluminum composite heat dissipation plate

Abstract

The invention relates to a manufacturing method of a copper-aluminum composite heat dissipation plate and the copper-aluminum composite heat dissipation plate. The manufacturing method comprises the steps of copper needle plate forming, copper needle plate mold entering and liquid aluminum coating forming. The copper-aluminum composite heat dissipation plate is manufactured through the process. According to the method, the copper needle plate with the heat dissipation needles is firstly machined, then the heat dissipation needles are wrapped with the liquid aluminum in the mold to obtain the aluminum-clad copper structure, then the copper-aluminum composite heat dissipation plate is obtained through diffusion welding, connection at the copper-aluminum interface is reliable, the heat conductivity of the heat dissipation plate is improved through a copper material, meanwhile, the corrosion resistance of the heat dissipation plate is improved through an aluminum material, and the service life of the heat dissipation plate is prolonged. And the advantages of the two materials are compatible.

Description

Technical Field

[0001] The present invention relates to the technical field of radiator manufacturing, and in particular to a method for manufacturing a copper-aluminum composite radiator plate. Background Art

[0002] A heat sink is a device that dissipates heat from heat-sensitive electronic components in electrical appliances. Pure copper has high thermal conductivity and can be directly soldered to power devices. However, when used in water-cooling applications, it is not corrosion-resistant and requires electroplating. It also has a high density and a high unit price. Aluminum has a low density and relatively low thermal conductivity, but when used in water-cooling applications, simple passivation can achieve good corrosion resistance without electroplating. Using a copper-aluminum composite can reduce the unit weight of the product while improving thermal conductivity compared to aluminum alloys.

[0003] Chinese patent CN201243012Y discloses a copper-aluminum composite heat sink for integrated circuit chips, comprising a copper layer, an aluminum layer, and a copper-aluminum bonding layer. The copper and aluminum layers are bonded face-to-face in a flat plate structure, resulting in a simple structure that cannot form an aluminum-clad copper structure.

[0004] Therefore, it is necessary to design a new molding method to solve the above problems. Summary of the Invention

[0005] The main purpose of the present invention is to provide a method for manufacturing a copper-aluminum composite heat sink, which can be obtained by a relatively simple manufacturing method. The copper-aluminum composite heat sink not only combines the high thermal conductivity of copper and the corrosion resistance of aluminum, but also ensures reliable connection at the copper-aluminum interface.

[0006] The present invention achieves the above-mentioned object through the following technical solution: A method for manufacturing a copper-aluminum composite heat sink, comprising the following steps: S1. Copper needle board forming: manufacturing the copper plate into a copper needle board, wherein the copper needle board has a structure of a bottom plate and a plurality of heat dissipation pins, and all the heat dissipation pins are located on the front side of the bottom plate; S2. Inserting the copper needle plate into the mold: placing the copper needle plate with its front side facing downward into the mold. The mold is provided with a forming cavity. The forming cavity has forming holes corresponding to the positions of the heat dissipation pins. The size of the forming holes is larger than the size of the heat dissipation pins. A gap is formed between the front structure of the copper needle plate and the forming cavity. S3. Liquid aluminum overmolding: Liquid aluminum is injected into the gap to form an aluminum-clad copper structure at the heat dissipation needle. The temperature is maintained at 500-630°C, the pressure is 100-3000 tons, and the time is 10-20 seconds. A diffusion layer is formed at the copper-aluminum interface, and finally cooled to form a copper-aluminum composite heat dissipation plate.

[0007] Specifically, the thickness of the aluminum material at the aluminum-clad copper structure is 0.5-2 mm.

[0008] Furthermore, the heat dissipation pins are formed by forging the upper surface of the copper plate.

[0009] Furthermore, the heat dissipation pins are formed by CNC machining the upper surface of the copper plate.

[0010] Furthermore, a plurality of protrusions are provided on the surface of the heat dissipation pin, and the height of the protrusions is no greater than the thickness of the aluminum material.

[0011] Furthermore, the surface of the heat dissipation pin is provided with a plurality of ridges extending in the horizontal direction, and the height of the ridges is not greater than the thickness of the aluminum material.

[0012] Specifically, the inner surface of the forming cavity has a plurality of guide grooves for guiding the aluminum material into each forming hole.

[0013] Another main purpose of the present invention is to provide a copper-aluminum composite heat sink, which can be used to manufacture heat sink pins with an aluminum-clad copper structure through the above process.

[0014] The present invention achieves the above-mentioned purpose through the following technical solution: a copper-aluminum composite heat sink is made by the manufacturing method of the copper-aluminum composite heat sink.

[0015] The beneficial effects of the technical solution of the present invention are: The present invention first processes a copper needle plate with heat dissipation needles, then wraps the heat dissipation needles with liquid aluminum in a mold to obtain an aluminum-clad copper structure, and then obtains a copper-aluminum composite heat dissipation plate by diffusion welding. The copper-aluminum interface is reliably connected, the thermal conductivity of the heat dissipation plate is improved by using copper material, and the corrosion resistance of the heat dissipation plate is improved by using aluminum material, thereby combining the advantages of both materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a cross-sectional diagram of the manufacturing method of the copper-aluminum composite heat sink in Example 1; Figure 2 This is a top view of the copper needle plate of Example 1; Figure 3 A top view of the mold used in Example 1; Figure 4 This is a cross-sectional diagram of the manufacturing method of the copper-aluminum composite heat sink in Example 2; Figure 5 This is a top partial cross-sectional view of the copper-aluminum composite heat sink of Example 2; Figure 6 This is a partial enlarged view of the heat dissipation pin in Example 3; Figure 7 This is a partial enlarged view of the heat dissipation pin in Example 4.

[0017] The following are marked in the figure: 1-copper plate, 1'-copper pin plate, 11-base plate, 12-heat sink pin, 121-bump, 122-ridge; 2-Aluminum; 3-Diffusion layer; 4-mold, 41-molding cavity, 42-molding hole, 43-guide groove. DETAILED DESCRIPTION

[0018] The present invention is further described in detail below with reference to specific embodiments.

[0019] Example 1: like Figures 1 to 3 As shown, a method for manufacturing a copper-aluminum composite heat sink comprises the following steps: S1. Copper needle plate forming: The copper plate 1 is manufactured into a copper needle plate 1 ′. The copper needle plate 1 ′ has a structure of a bottom plate 11 and a plurality of heat dissipation needles 12 . All the heat dissipation needles 12 are located on the front of the bottom plate 11 . The heat dissipation needles 12 are formed by forging the upper surface of the copper plate 1 .

[0020] Heat sink pins 12 are formed by forging, resulting in a cylindrical structure with the ends no smaller than the base. Heat sink pins 12 form the foundation for the aluminum material 3. Due to the requirements of the forging process, the cross-section of heat sink pins 12 cannot be too slender. They can be circular, elliptical, teardrop-shaped, plum blossom-shaped, or various convex polygonal structures.

[0021] S2. Place the copper needle plate 1' into the mold: Place the copper needle plate 1' with its front side facing downward into the mold 4. A forming cavity 41 is provided in the mold 4. The forming cavity 41 has forming holes 42 corresponding to the positions of the heat dissipation needles 12. The size of the forming holes 42 is larger than that of the heat dissipation needles 12. A gap is formed between the front structure of the copper needle plate 1' and the forming cavity 41.

[0022] The melting point of copper is 1083.4°C, and the melting point of aluminum is 660.37°C. When aluminum is in a liquid state, copper can remain solid. Therefore, in order to obtain an aluminum-clad copper structure, this forming method first precisely processes the copper needle plate 1'. The copper needle plate 1' and the mold 4 together form a cavity for the aluminum material 2. When the aluminum material 2 is injected into the cavity, the gap between the copper needle plate 1' and the mold 4 will be filled, thereby forming a thin layer of aluminum material 2 on the outside of the heat sink needle 12. To facilitate the diffusion of the aluminum material 2, the inner surface of the forming cavity 41 has a number of guide grooves 43 that guide the aluminum material 2 into each forming hole 42. The pressure of the liquid aluminum in the cavity is automatically evenly distributed, so a uniform thin layer of aluminum will be obtained on the heat sink needle 12.

[0023] S3, Liquid Aluminum Overmolding: Liquid aluminum is injected into the gap (where aluminum material 2 is located), forming an aluminum-clad copper structure at heat sink pin 12. The temperature is maintained at 600°C, the pressure is 1000 tons, and the molding process is continued for 20 seconds. A diffusion layer 3 is formed at the copper-aluminum interface. Finally, the mold is cooled to form a copper-aluminum composite heat sink. The thickness of the aluminum material at the aluminum-clad copper structure is 1 mm.

[0024] In practice, depending on the size of the heat sink, the aluminum thickness of the aluminum-clad copper structure can range from 0.5 to 2 mm, and the pressure in step S3 can range from 100 to 3000 tons. Diffusion welding only needs to prevent the aluminum from melting, so the temperature range is 500 to 630°C.

[0025] By adopting the aluminum-clad copper method, due to its location, the copper base plate 11 can transfer heat horizontally, and the heat dissipation pins 12 can better transfer heat vertically (compared to pure aluminum pins), achieving better heat transfer, corrosion resistance, weight reduction, and cost reduction.

[0026] After the liquid aluminum is wrapped around the heat dissipation pins 12, the two metals are welded by diffusion welding, which makes the structure compact, avoids the air between the interfaces from affecting the heat dissipation efficiency, and ensures the high thermal conductivity of the heat dissipation plate.

[0027] In summary, the present invention first processes a copper needle plate 1' with a heat dissipation needle 12, then wraps the heat dissipation needle 12 with liquid aluminum in a mold 4 to obtain an aluminum-clad copper structure, and then obtains a copper-aluminum composite heat dissipation plate by diffusion welding. The connection at the copper-aluminum interface is reliable, the copper material is used to improve the thermal conductivity of the heat dissipation plate, and the aluminum material is used to improve the corrosion resistance of the heat dissipation plate, thereby combining the advantages of the two materials.

[0028] Example 2: like Figure 4 and Figure 5 As shown, the difference from Example 1 is that the heat dissipation pins 12 are formed by CNC machining the upper surface of the copper plate 1. The cross section of the heat dissipation pins 12 is an elongated structure.

[0029] Compared to forging, CNC machining can produce a wider range of structures, such as heat sink fins with a large aspect ratio, but it is not limited to this structure. However, its disadvantage is that it removes a lot of material from the front of the base plate 11, with the thickness of the cut being equal to the height of the heat sink pins 12, resulting in a relatively wasteful amount of material.

[0030] Example 3: like Figure 6 As shown, the difference from embodiment 2 is that a plurality of protrusions 121 are provided on the surface of the heat dissipation pin 12 , and the height of the protrusions 121 is not greater than the thickness of the aluminum material 2 .

[0031] Bumps 121 cannot be manufactured using forging, as this would break the heat sink pins 12. Bumps 121 allow the heat sink pins 12 to exert a certain vertical force on the newly solidified aluminum material 2, preventing the copper and aluminum from separating during the cooling process. Bumps 121 are not exposed on the surface of the aluminum material 2, so the aluminum material 2 still has a complete corrosion protection effect.

[0032] Example 4: like Figure 7 As shown, the difference from Example 3 is that the ridges 122 are replaced with the bumps 121 on the surface of the heat dissipation pin 12. The ridges 122 extend horizontally (the surface of the bottom plate 11 is horizontal). The height of the ridges 122 is no greater than the thickness of the aluminum material 2.

[0033] The ridge 122 can also make the heat sink 12 produce a certain vertical force on the newly solidified aluminum material 2 to prevent the copper and aluminum from separating during the cooling process. The ridge 122 will not be exposed on the surface of the aluminum material 2, so the aluminum material 2 can still play a complete anti-corrosion role.

[0034] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a copper-aluminum composite heat sink, characterized in that the steps include: S1. Copper needle board forming: manufacturing the copper plate into a copper needle board, wherein the copper needle board has a structure of a bottom plate and a plurality of heat dissipation pins, and all the heat dissipation pins are located on the front side of the bottom plate; S2. Inserting the copper needle plate into the mold: placing the copper needle plate with its front side facing downward into the mold. The mold is provided with a forming cavity. The forming cavity has forming holes corresponding to the positions of the heat dissipation pins. The size of the forming holes is larger than the size of the heat dissipation pins. A gap is formed between the front structure of the copper needle plate and the forming cavity. S3. Liquid aluminum overmolding: Liquid aluminum is injected into the gap to form an aluminum-clad copper structure at the heat dissipation needle. The temperature is maintained at 500-630°C, the pressure is 100-3000 tons, and the time is 10-20 seconds. A diffusion layer is formed at the copper-aluminum interface, and finally cooled to form a copper-aluminum composite heat dissipation plate.

2. The method for manufacturing the copper-aluminum composite heat sink according to claim 1, wherein: The thickness of the aluminum material at the aluminum-clad copper structure is 0.5-2 mm.

3. The method for manufacturing the copper-aluminum composite heat sink according to claim 2, wherein: The heat dissipation pins are formed by forging the upper surface of the copper plate.

4. The method for manufacturing the copper-aluminum composite heat sink according to claim 2, wherein: The heat dissipation pins are formed by CNC machining the upper surface of the copper plate.

5. The method for manufacturing the copper-aluminum composite heat sink according to claim 4, characterized in that: The surface of the heat dissipation pin is provided with a plurality of protrusions, and the height of the protrusions is not greater than the thickness of the aluminum material.

6. The method for manufacturing the copper-aluminum composite heat sink according to claim 4, wherein: The surface of the heat dissipation pin is provided with a plurality of ridges extending in the horizontal direction, and the height of the ridges is not greater than the thickness of the aluminum material.

7. The method for manufacturing the copper-aluminum composite heat sink according to claim 1, wherein: The inner surface of the forming cavity is provided with a plurality of guide grooves for guiding the aluminum material into each forming hole.

8. A copper-aluminum composite heat sink, characterized by: The copper-aluminum composite heat sink is manufactured by the manufacturing method of any one of claims 1-6.

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