Method for manufacturing composite heat dissipation plate through interference fit and copper-aluminum composite heat dissipation plate

Abstract

The invention relates to a method for manufacturing a composite heat dissipation plate through interference fit and a copper-aluminum composite heat dissipation plate. The process comprises the steps of copper needle plate forming, aluminum needle plate forming, interference fit and diffusion welding. 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 and the aluminum needle plate with the heat dissipation columns are obtained through machining firstly, then the copper needle plate and the aluminum needle plate are in interference fit 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, and the heat dissipation efficiency is improved. And meanwhile, the aluminum material is used for improving the corrosion resistance of the heat dissipation plate, and the advantages of the two materials are compatible.

Description

Technical Field

[0001] The invention relates to the technical field of radiator manufacturing, and in particular to a method for manufacturing a composite radiator plate by interference fitting. 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 CN110849190A discloses a copper-aluminum composite heat sink and its processing method. The heat sink comprises an aluminum alloy heat sink body and a copper base plate embedded in the heat-conducting surface of the aluminum alloy heat sink body in a slot-like configuration. The copper base plate has an opening above the slot, and a capillary plate is placed within the slot. The direct contact surface between the copper base plate and the aluminum alloy heat sink body is minimal, so heat transfer primarily occurs through the capillary plate. If this contact is unreliable, the heat dissipation effect will be compromised.

[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 composite heat sink by interference fit, which can obtain a copper-aluminum composite heat sink by interference fit followed by diffusion welding. It not only combines the high thermal conductivity of copper and the corrosion resistance of aluminum, but also provides 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 composite heat dissipation plate by interference fit, comprising the following steps: S1. Copper needle board forming: manufacturing a copper needle board, wherein the copper needle board comprises a first bottom plate and a plurality of heat dissipation needles, wherein all the heat dissipation needles are located on the front side of the first bottom plate; S2. Aluminum needle plate forming: manufacturing an aluminum needle plate, the aluminum needle plate having a second bottom plate and a plurality of heat dissipation posts. All heat dissipation posts are located on the front of the second bottom plate and have the same layout as the heat dissipation pins. Each heat dissipation post has a cavity inside that is interference-fitted with the corresponding heat dissipation pin. S3, interference fit: press the front of the copper needle plate into the back of the aluminum needle plate, so that each heat dissipation needle has an interference fit with its corresponding cavity, with an interference amount of 0.05-0.1mm, to form a composite plate; S4, diffusion welding: the composite plate is maintained at a temperature of 500-630°C, a pressure of 100-1000 tons, and a time of 10-15 seconds to form a diffusion layer at the copper-aluminum interface, and finally cooled to form a copper-aluminum composite heat sink.

[0007] Specifically, the copper needle plate is provided with an exhaust hole extending from the top of the heat dissipation needle to the back of the first bottom plate, and the exhaust hole is processed by a drill bit with a diameter not exceeding 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] Specifically, the aluminum needle plate is cast from aluminum or aluminum alloy.

[0011] Furthermore, the wall thickness of the heat dissipation column is 0.5~2mm.

[0012] Specifically, the top end of the heat dissipation pin has a tapered surface.

[0013] Specifically, the cross-sectional shape of the heat dissipation pin is circular, square, diamond, elliptical, teardrop-shaped or plum blossom-shaped.

[0014] 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.

[0015] The present invention achieves the above-mentioned purpose through the following technical solutions: A copper-aluminum composite heat sink is made by the above-mentioned method for manufacturing a composite heat sink by interference fit.

[0016] 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

[0017] Figure 1 This is a cross-sectional view of the material of the copper-aluminum composite heat sink manufacturing method in Example 1; Figure 2 This is a cross-sectional view of the copper-aluminum composite heat sink at the heat sink pin of Example 1; Figure 3 This is a cross-sectional view of the copper-aluminum composite heat sink at the heat sink pin of Example 2; Figure 4This is a partial axial cross-sectional view of the copper-aluminum composite heat dissipation plate of Example 2 at the heat dissipation pin.

[0018] The following are marked in the figure: 1-copper needle plate, 11-first bottom plate, 12-heat dissipation needle, 121-exhaust hole, 122-tapered surface; 2-aluminum needle plate, 21-second bottom plate, 22-heat dissipation column, 221-cavity; 3-Diffusion layer. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below with reference to specific embodiments.

[0020] Example 1: like Figure 1 and Figure 2 As shown, a method for manufacturing a composite heat sink by interference fit comprises the following steps: S1. Copper needle board forming: manufacturing a copper needle board 1 , which comprises a first bottom plate 11 and a plurality of heat dissipation needles 12 , all of which are located on the front side of the first bottom plate 11 .

[0021] The heat sink pins 12 can be formed by forging or CNC machining the upper surface of the copper plate. The heat sink pins 12 serve as the base for the aluminum wrapping. In this embodiment, the cross-section of the heat sink pins 12 is a square structure (with rounded corners).

[0022] S2. Aluminum needle plate forming: manufacture an aluminum needle plate 2, which has a second base plate 21 and a plurality of heat dissipation columns 22. All heat dissipation columns 22 are located on the front of the second base plate 21 and have the same layout as the heat dissipation needles 12. Each heat dissipation column 22 has a cavity 221 inside that is interference fit with the corresponding heat dissipation needle 12.

[0023] Because aluminum has a melting point of 660.37°C, and aluminum alloys have an even lower melting point, casting the aluminum needle plate 2 reduces energy consumption and allows for rapid production. In practical applications, the aluminum needle plate 2 can also be formed by forging or CNC machining. The heat dissipation posts 22 and heat dissipation pins 12 must be aligned to form an aluminum-clad copper structure, requiring a corresponding layout. The cavity 221 must be slightly smaller than the heat dissipation pins 12 to achieve an interference fit.

[0024] S3. Interference fit: Press the front of the copper needle plate 1 into the back of the aluminum needle plate 2 so that each heat dissipation needle 12 has an interference fit with its corresponding cavity 221 with an interference amount of 0.05-0.1 mm to form a composite plate.

[0025] The aluminum-clad copper method is adopted. Due to its location, the copper first 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, reduced weight, and reduced costs. In order to avoid the heat dissipation pins 12 being crushed due to failure to align with the cavity 221 during interference fit, the interference should not be too large. Because in this embodiment, the cross-section of the cavity 221 is a square and the cross-section of the heat dissipation pins 12 is a rounded square, after the two are matched, the cavity 221 can also form an exhaust channel, so there is no need to worry about air trapping. In actual applications, the cross-sectional shape of the heat dissipation pins 12 can also be a shape with obvious edges and corners, such as a diamond or plum blossom, so that an exhaust channel can be formed by rounding the edges and corners.

[0026] S4, diffusion welding: maintain the temperature of the composite plate at 500~630℃, the pressure at 100~1000 tons, and the time at 10~15s to form a diffusion layer 3 at the copper-aluminum interface, and finally cool it to form a copper-aluminum composite heat sink.

[0027] After the composite plate is formed, diffusion welding is used to weld the copper and aluminum metals together to form a compact structure, thereby preventing air from affecting the heat dissipation efficiency between the interfaces and ensuring the high thermal conductivity of the heat dissipation plate.

[0028] In summary, the present invention first processes a copper needle plate 1 with a heat dissipation needle 12 and an aluminum needle plate 2 with a heat dissipation column 22, and then interference fits the copper needle plate 1 and the aluminum needle plate 2 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, and the copper material is used to improve the thermal conductivity of the heat dissipation plate, while the aluminum material is used to improve the corrosion resistance of the heat dissipation plate, thereby combining the advantages of both materials.

[0029] Example 2: like Figure 3 and Figure 4 As shown, the difference from Example 1 is that the cross-section of the heat dissipation pin 12 is circular. The cavity 221 in the heat dissipation column 22 is also circular, and the inner diameter of the cavity 221 is slightly smaller than the outer diameter of the heat dissipation pin 12 (interference margin of 0.05-0.1mm). In addition, the copper pin plate 1 is provided with an exhaust hole 121 extending from the top of the heat dissipation pin 12 to the back of the first base plate 11. The exhaust hole 121 is machined with a drill bit with a diameter of no more than 2mm.

[0030] In this embodiment, the outer wall of the heat sink pin 12 is completely in contact with the inner wall of the cavity 221, so vent holes 121 are required to allow air to escape during the interference fit. The diameter of the vent holes 121 should not be too large, as this ensures the strength of the heat sink pin 12 while minimizing the impact on heat transfer. In practical applications, the cross-sectional shape of the heat sink pin 12 can also be an elliptical, teardrop-shaped, or other smooth shape. These shapes are not suitable for rounded corners, so only space inside for the vent holes 121 is required.

[0031] Figure 4 As shown in FIG, the top of the heat dissipation pin 12 has a tapered surface 122. This is because the heat dissipation pin 12 is more easily aligned with the position of the cavity 221, thereby smoothly assembling the copper pin plate 1 and the aluminum pin plate 2.

[0032] 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 composite heat sink by interference fit, characterized in that the steps include: S1. Copper needle board forming: manufacturing a copper needle board, wherein the copper needle board comprises a first bottom plate and a plurality of heat dissipation needles, wherein all the heat dissipation needles are located on the front side of the first bottom plate; S2. Aluminum needle plate forming: manufacturing an aluminum needle plate, the aluminum needle plate having a second bottom plate and a plurality of heat dissipation posts. All heat dissipation posts are located on the front of the second bottom plate and have the same layout as the heat dissipation pins. Each heat dissipation post has a cavity inside that is interference-fitted with the corresponding heat dissipation pin. S3, interference fit: press the front of the copper needle plate into the back of the aluminum needle plate, so that each heat dissipation needle has an interference fit with its corresponding cavity, with an interference amount of 0.05-0.1mm, to form a composite plate; S4, diffusion welding: the composite plate is maintained at a temperature of 500-630°C, a pressure of 100-1000 tons, and a time of 10-15 seconds to form a diffusion layer at the copper-aluminum interface, and finally cooled to form a copper-aluminum composite heat sink.

2. The method for manufacturing a composite heat dissipation plate by interference fit according to claim 1, characterized in that: The copper needle plate is provided with an exhaust hole extending from the top of the heat dissipation needle to the back of the first bottom plate, and the exhaust hole is processed by a drill bit with a diameter not exceeding 2 mm.

3. The method for manufacturing a composite heat dissipation plate by interference fit according to claim 2, characterized in that: The heat dissipation pins are formed by forging the upper surface of the copper plate.

4. The method for manufacturing a composite heat dissipation plate by interference fit according to claim 2, characterized in that: The heat dissipation pins are formed by CNC machining the upper surface of the copper plate.

5. The method for manufacturing a composite heat dissipation plate by interference fit according to claim 1, characterized in that: The aluminum needle plate is cast from aluminum or aluminum alloy.

6. The method for manufacturing a composite heat dissipation plate by interference fit according to claim 5, characterized in that: The wall thickness of the heat dissipation column is 0.5-2 mm.

7. The method for manufacturing a composite heat dissipation plate by interference fit according to claim 1, characterized in that: The top end of the heat dissipation pin has a tapered surface.

8. The method for manufacturing a composite heat dissipation plate by interference fit according to claim 1, characterized in that: The cross-sectional shape of the heat dissipation pin is circular, square, diamond, elliptical, teardrop-shaped or plum blossom-shaped.

9. A copper-aluminum composite heat sink, characterized by: The composite heat sink is manufactured by the method for manufacturing the composite heat sink by interference fit according to any one of claims 1 to 8.

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