Aluminum temperature balancing plate and manufacturing method thereof

Abstract

The present invention provides a method for making an aluminum temperature equalizing plate, firstly stamping out an upper cover and a lower cover through a mold, comprising the following steps: step 1, cleaning and removing oil stains on the surface; step 2, placing the lower cover into the base graphite, filling aluminum powder through a powder filling fixture, and covering the upper and lower covers with sintered graphite; step 3, processing a mesh capillary on the upper cover; step 4, evenly sprinkling aluminum powder in the groove of the lower cover of the powder ring sintered graphite, placing it in a hot press furnace for sintering, and taking out the powder ring; step 5, placing an aluminum column in the hole of the aluminum powder of the lower cover, and sleeve the powder ring on the aluminum column, and after the upper and lower covers are assembled, placing them in a hot press furnace for sintering to form a semi-finished product; step 6, welding the injection pipe to the semi-finished product, evacuating, injecting working medium, and sealing the injection pipe. The beneficial effects of the present invention are: its internal capillary structure is sintered aluminum powder, has strong capillary capacity, high heat dissipation power, and can provide a good heat dissipation effect under reverse gravity conditions.

Description

Technical Field

[0001] The invention belongs to the technical field of heat conduction, and mainly relates to an aluminum temperature equalizing plate and a manufacturing method thereof. Background Art

[0002] The development trend of electronic components is lightweight and high power. In this context, more powerful heat dissipation components are needed to support their development. As a highly efficient phase change heat transfer component, aluminum heat spreader can quickly transfer the heat gathered on the surface of the heat source to the large area of ​​condensation surface. Through the internal gas-liquid two-phase change, the heat is quickly transferred and dissipated. Compared with copper and copper alloys, aluminum and aluminum alloys have advantages such as small specific gravity, low price and abundant resources. Therefore, aluminum heat spreader will inevitably have a place in the mainstream heat dissipation market in the future.

[0003] At present, the internal capillary structure of the mass-produced aluminum heat spreaders on the market is mostly a groove structure, which has poor comprehensive capillary performance, low heat dissipation power, and cannot meet the heat dissipation requirements under reverse gravity conditions. With the continuous advancement of 5G technology, the emergence of more and more high-power devices has made traditional aluminum heat spreaders unable to meet the requirements, and the liquid working fluid has a slow reflux speed in the reverse gravity working environment, which reduces the heat transfer efficiency of the aluminum heat spreader and cannot meet the heat dissipation requirements under reverse gravity conditions. Summary of the invention

[0004] In view of the defects of the traditional aluminum heat sink with low heat dissipation power and inability to meet the requirements of counter-gravity work, the present invention provides an aluminum heat sink with an internal capillary structure of sintered aluminum powder, strong capillary capacity, high heat dissipation power, and good heat dissipation effect under counter-gravity conditions. This is achieved through the following scheme.

[0005] A method for manufacturing an aluminum temperature-averaging plate includes first punching out an upper cover and a lower cover through a mold, and comprising the following steps:

[0006] Step 1: Use alcohol or acetone to ultrasonically clean the upper and lower covers for 3-10 minutes to remove surface oil stains;

[0007] Step 2: Install the lower cover into the base graphite, and install the powder filling jig into the lower cover. There is a certain gap between the powder filling jig and the lower cover. Fill the gap evenly with aluminum powder through the powder filling port on the powder filling jig. After the powder filling is completed, remove the powder filling jig and cover the upper and lower covers with sintered graphite.

[0008] Step 3: Use a laser engraving machine to process mesh capillaries on the upper cover;

[0009] Step 4, evenly sprinkle aluminum powder in the groove of the powder ring sintered graphite lower cover, and cover the powder ring sintered graphite upper cover on the powder ring sintered graphite lower cover through four positioning pillars, put it into the hot pressing furnace for sintering, remove the powder ring sintered graphite upper cover, and take out the powder ring located in the groove of the powder ring sintered graphite lower cover;

[0010] Step 5: Place the aluminum column in the hole of the aluminum powder in the lower cover, and put the powder ring on the aluminum column. After the upper cover and the lower cover are assembled, put them into the base graphite, and sinter them in a hot press furnace to form a semi-finished product;

[0011] Step 6: Use high-frequency welding to weld the liquid injection pipe to the semi-finished product. After welding, evacuate the liquid injection pipe, inject the working medium, clamp the liquid injection pipe, and then use argon arc welding to seal the liquid injection pipe.

[0012] An aluminum temperature equalizing plate manufactured by the above process comprises an upper cover and a lower cover, wherein a mesh capillary is arranged on the inner side of the upper cover, and an aluminum powder sintered layer is arranged inside the lower cover, wherein a plurality of holes are evenly arranged on the aluminum powder sintered layer, and the holes are used to install an aluminum column, and a powder ring is sleeved on the aluminum column, and the mesh capillary is composed of a plurality of 45° and 135° grooves staggered, wherein the depth of the groove is 0.05-0.1mm, and the spacing between adjacent grooves is 0.05-0.1mm.

[0013] The beneficial effects of the present invention are as follows: its internal capillary structure is sintered aluminum powder, has strong capillary capacity, high heat dissipation power, and can provide good heat dissipation effect under reverse gravity conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a flow chart of manufacturing the aluminum temperature equalizing plate in an embodiment of the present invention.

[0015] Figure 2 Schematic diagram of the structure of the aluminum temperature equalizing plate in an embodiment of the present invention.

[0016] Figure 3 Schematic diagram of the capillary structure of the upper cover of the aluminum temperature equalizing plate in an embodiment of the present invention.

[0017] Figure 4 Schematic diagram of the powder ring sintered graphite structure in an embodiment of the present invention.

[0018] Figure 5 It is a schematic diagram of the powder ring sintered graphite upper cover structure in an embodiment of the present invention.

[0019] Figure 6 It is a schematic diagram of the powder ring sintered graphite lower cover structure in an embodiment of the present invention.

[0020] Figure 7 Schematic diagram of the combination of the upper and lower covers of the aluminum temperature balancing plate in an embodiment of the present invention.

[0021] Figure 8 Schematic diagram of the powder filling fixture structure of the lower cover of the aluminum temperature equalizing plate in an embodiment of the present invention.

[0022] Fig. 9 It is a schematic diagram of the sintered graphite structure of the lower cover of the aluminum temperature equalizing plate in an embodiment of the present invention.

[0023] Fig.10 It is a schematic diagram of the capillary sintering structure of the lower cover of the aluminum temperature equalizing plate in an embodiment of the present invention.

[0024] Fig.11 Schematic diagram of the finished structure of the aluminum temperature equalizing plate in an embodiment of the present invention. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the embodiments. The embodiments described are only a part of the present invention. These embodiments are only used to explain the present invention and do not constitute any limitation to the scope of the present invention.

[0026] like Figure 1-11 As shown, it is a flowchart of the production process of this application, which includes the following steps:

[0027] S1, using a mold to stamp out an upper cover and a lower cover, the upper cover and the lower cover are made of a composite aluminum alloy, specifically a composite material of grade 3003 aluminum alloy and grade 4045 aluminum alloy, wherein the thickness of the 4045 aluminum alloy accounts for 10% to 20%, and the concave surface of the middle and lower covers is made of 4045 material.

[0028] The upper cover and the lower cover may also be made of other single-component aluminum alloys or two-layer or three-layer composite aluminum alloys or copper-aluminum composite materials, such as 3003 aluminum alloy, 4045 aluminum alloy and 3003 aluminum alloy, 3003 aluminum alloy, 4343 aluminum alloy, 3003 aluminum alloy, etc.

[0029] S2. After stamping, use alcohol or acetone to ultrasonically clean it for 3-10 minutes to remove oil stains on the surface.

[0030] S3, such as Figure 7 , 10 As shown, after cleaning, the lower cover 2 is installed in the base graphite 83, and the powder filling fixture 85 is installed in the lower cover. There is a certain gap between the powder filling fixture 85 and the lower cover 2. Through the powder filling port 852 on the powder filling fixture (as shown in FIG. Figure 8 As shown), fill the gap with aluminum powder evenly. After the powder filling is completed, remove the powder filling fixture and cover the upper and lower covers with sintered graphite 81 (as shown Fig. 9As shown). The height of the limiting column 811 of the lower cover sintered graphite 81 is about 10-40% higher than the height of the limiting column 851 of the powder filling fixture. This is because aluminum is chemically active and an oxide film is easily formed on the surface, and the oxide film cannot be reduced by hydrogen. Therefore, it is necessary to apply pressure during the sintering process to achieve the effect of destroying the oxide layer, so that fresh aluminum is exposed and metallurgical bonding can be formed at a temperature not higher than the melting point.

[0031] Put it into a hot press furnace for sintering, the sintering temperature is 500-650℃, the sintering time is 1-5h, the sintering pressure is 0.5-2kg / mm2, and pure nitrogen or nitrogen-hydrogen mixed gas is introduced for protection during sintering.

[0032] In a preferred embodiment of the present invention, the sintering temperature is 600°C, the sintering time is 3h, the sintering pressure is 1kg / mm2, the protective gas is pure nitrogen, and the lower cover sintered graphite is taken out after sintering is completed. At this time, the lower cover aluminum powder is tightly combined with the lower cover, and the porosity of the lower cover aluminum powder is 30-50%.

[0033] In other embodiments of the present invention, the hot press furnace may be replaced by resistance welding.

[0034] S4, use a laser engraving machine to process a mesh capillary 11 on the upper cover, such as Figure 3 As shown, it is composed of several 45° and 135° grooves staggered, the depth of the groove is 0.05-0.1mm, and the spacing between adjacent grooves is 0.05-0.1mm. If the upper cover material is a composite material of 3003 aluminum alloy and 4045 aluminum alloy, the processing surface is 4045 material.

[0035] S5, such as Figure 4 , Figure 5 , Figure 6 As shown, the powder ring sintered graphite 7 is used to make aluminum alloy powder rings. The aluminum powder is evenly sprinkled in the groove 75 of the powder ring sintered graphite lower cover 72. After the aluminum powder fills the groove, the excess aluminum powder is removed, and the powder ring sintered graphite upper cover 71 is covered in the positioning hole 76 of the powder ring sintered graphite lower cover through four positioning columns 73. The height of the limiting ring 74 in the powder ring sintered graphite upper cover is 60%-90% of the depth of the limiting groove 75 in the powder ring sintered graphite lower cover. The purpose is to compress the aluminum powder during the sintering process, and the aluminum powders can be squeezed against each other to remove the oxide layer, so as to achieve the metallurgical bonding of aluminum and aluminum.

[0036] Put it into a hot press furnace for sintering, the sintering temperature is 500-650℃, the sintering time is 1-5h, and the sintering pressure is 0.5-2kg / mm 2 During sintering, pure nitrogen or nitrogen-hydrogen mixed gas is introduced for protection.

[0037] The sintering temperature used in the preferred embodiment of the present invention is 600°C, the sintering time is 3h, and the sintering pressure is 1kg / mm2 The protective gas is pure nitrogen. After sintering, remove the upper cover of the powder ring sintered graphite, and take out the powder ring located in the groove of the lower cover of the powder ring sintered graphite. The porosity of the powder ring is 30%-50%.

[0038] S6, such as Figure 2 , 10 As shown, the aluminum column 5 is placed in the hole 31 of the lower cover aluminum powder sintered in S1, and the powder ring 4 removed in S3 is put on the aluminum column, and then the upper cover 1 laser-engraved in S2 is covered on the lower cover 2, and the positioning groove 13 of the upper cover is matched with the positioning column 21 of the lower cover.

[0039] After assembly, put it into the base graphite 83, such as Fig.10 As shown, it is then put into a hot press furnace for sintering, the sintering temperature is 570-630℃, the sintering time is 1-5h, and the sintering pressure is 0.5-2kg / mm 2 During sintering, pure nitrogen or nitrogen-hydrogen mixed gas is introduced for protection, and the sintering is completed to form a semi-finished product.

[0040] The preferred embodiment of the present invention uses a sintering temperature of 620° C., a sintering time of 1 h, a sintering pressure of 0.5 kg / mm ​​2 , and a protective gas of pure nitrogen.

[0041] In other embodiments of the present invention, the hot pressing furnace may be replaced by a brazing process.

[0042] S7, such as Fig.11 As shown, high-frequency welding is used to weld the injection pipe 6 and the sintered semi-finished product S6. After welding is completed, vacuum is evacuated and working medium is injected through the injection pipe 6. The working medium is generally acetone or R1233zd refrigerant, which needs to be carried out on a negative pressure filling device. After the working medium is injected, the injection pipe is clamped, and then argon arc welding is used to seal the injection pipe.

[0043] In the embodiment of the present invention, welding the liquid injection tube and the sintered semi-finished product can be replaced by welding using a brazing furnace.

[0044] In other embodiments of the present invention, the powder sintering process adopts hot pressing sintering process, the sintering temperature is 500-650℃, the sintering time is 1-5h, and the sintering pressure is 0.5-2kg / mm 2 During sintering, pure nitrogen or nitrogen-hydrogen mixed gas is introduced for protection.

[0045] like Figure 2 , 3As shown in Figure 11, an aluminum temperature equalizing plate 10 made by the above process includes an upper cover 1 and a lower cover 2. A mesh capillary 11 is arranged on the inner side of the upper cover, and an aluminum powder sintered layer 3 is arranged in the lower cover. The aluminum powder sintered layer has a plurality of holes 31 evenly arranged therein, and the holes are used to install an aluminum column 5. A powder ring 4 is sleeved on the aluminum column. The mesh capillary 11 is composed of a plurality of 45° and 135° grooves staggered together. The depth of the groove is 0.05-0.1mm, and the spacing between adjacent grooves is 0.05-0.1mm.

[0046] The upper cover 1 is covered on the lower cover 2, and the positioning grooves 13 of the upper cover cooperate with the positioning posts 21 of the lower cover.

[0047] The end of the upper cover is provided with a mounting groove 15 for welding the liquid injection pipe 6 .

[0048] The aluminum temperature equalizer of the present invention can provide a good heat dissipation effect under reverse gravity conditions. The temperature equalizer for burning powder on the market is generally made of copper, the upper and lower covers are pure copper, the support is pure copper, the powder column is pure copper powder, the lower cover capillary is copper powder (or copper mesh), and the upper cover capillary is copper mesh. The principle and reason are as follows: the metallic activity of copper ranks after hydrogen, so it can be reduced by passing nitrogen and hydrogen mixed gas at high temperature. The pure copper leaked out of the reduction can be combined with each other at a temperature close to the melting point of pure copper (900-980℃). The copper powder particles are tightly combined and have a certain porosity (about 40-50%). The tiny holes have a capillary effect (the same is true for the copper mesh), which can absorb water under reverse gravity conditions and diffuse to the entire area with copper powder.

[0049] The counter-gravity heat dissipation principle of the present invention is similar to that of the copper temperature-averaging plate. The difficulty lies in the bonding between the aluminum powder particles. This is because aluminum has active chemical properties, and an oxide film is easily formed on the surface. It has a high melting point (2050°C) and the oxide film cannot be reduced by hydrogen. Therefore, it is necessary to apply pressure during the sintering process to achieve the effect of destroying the oxide layer, so that fresh aluminum is exposed and a metallurgical bond can be formed at a temperature not higher than the melting point. From the internal structure of the aluminum temperature-averaging plate described in the present invention, the laser-carved mesh structure of the upper cover has a capillary effect. After absorbing the working fluid (acetone, ethanol), the capillary ability can resist gravity and climb against gravity. Similarly, the aluminum powder of the lower cover has a stronger capillary ability, and the powder ring connecting the upper and lower covers capillaries connects the upper and lower covers, so the whole has a complete capillary ability. In other words, good heat dissipation can be achieved under counter-gravity conditions. The internal capillaries of the aluminum temperature equalizing plates currently on the market are fins, grooves, etc., and their capillary ability is much worse than that of aluminum powder, and their capillary structure is discontinuous (the middle support does not have a capillary effect). They cannot work under reverse gravity conditions, but can only work under positive gravity conditions (using gravity to make the water on the condensation surface naturally drip to the evaporation surface).

[0050] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for manufacturing an aluminum temperature equalizing plate, firstly stamping out an upper cover and a lower cover through a mold, characterized in that: The steps include: Step 1: Use alcohol or acetone to ultrasonically clean the upper cover and the lower cover for 3-10 minutes to remove the oil stains on the surface; Step 2: Install the lower cover into the base graphite, and install the powder filling jig into the lower cover. There is a certain gap between the powder filling jig and the lower cover. Fill the gap evenly with aluminum powder through the powder filling port on the powder filling jig. After the powder filling is completed, remove the powder filling jig and cover the upper and lower covers with sintered graphite. Step 3: Use a laser engraving machine to process mesh capillaries on the upper cover; Step 4, evenly sprinkle aluminum powder in the groove of the powder ring sintered graphite lower cover, and cover the powder ring sintered graphite upper cover on the powder ring sintered graphite lower cover through four positioning pillars, put it into the hot pressing furnace for sintering, remove the powder ring sintered graphite upper cover, and take out the powder ring located in the groove of the powder ring sintered graphite lower cover; Step 5: Place the aluminum column in the hole of the aluminum powder in the lower cover, and put the powder ring on the aluminum column. After the upper cover and the lower cover are assembled, put them into the base graphite, and put them into the hot press furnace for sintering to form a semi-finished product; Step 6: Use high-frequency welding to weld the liquid injection pipe to the semi-finished product. After welding, evacuate the liquid injection pipe, inject the working medium, clamp the liquid injection pipe, and then use argon arc welding to seal the liquid injection pipe. In step 2, the hot pressing furnace is used for sintering, the sintering temperature is 500-650°C, the sintering time is 1-5h, the sintering pressure is 0.5-2kg / mm2, and pure nitrogen or nitrogen-hydrogen mixed gas is introduced for protection during sintering. After sintering, the porosity of the lower cover aluminum powder is 30-50%; In step 4, the hot pressing furnace is used for sintering, the sintering temperature is 500-650°C, the sintering time is 1-5h, the sintering pressure is 0.5-2kg / mm2, and pure nitrogen or nitrogen-hydrogen mixed gas is introduced for protection during sintering. After sintering, the upper cover of the powder ring sintered graphite is removed, and the powder ring located in the groove of the lower cover of the powder ring sintered graphite is taken out. The porosity of the powder ring is 30%-50%; In step 5, the hot pressing furnace is used for sintering, the sintering temperature is 570-630°C, the sintering time is 1-5h, the sintering pressure is 0.5-2kg / mm2, and pure nitrogen or nitrogen-hydrogen mixed gas is introduced for protection during sintering; In step 2, the height of the limit column of the sintered graphite of the lower cover is about 10-40% higher than the height of the limit column of the powder filling fixture; In step 4, the height of the limiting ring in the upper cover of the powder ring sintered graphite is 60%-90% of the depth of the limiting groove in the lower cover of the powder ring sintered graphite.

2. The method according to claim 1, characterized in that: The mesh capillary is composed of a plurality of grooves at 45° and 135°, the depth of the grooves is 0.05-0.1 mm, and the spacing between adjacent grooves is 0.05-0.1 mm.

3. The method according to claim 1, characterized in that: The upper cover and the lower cover are made of a composite material of 3003 aluminum alloy and 4045 aluminum alloy, wherein the thickness of 4045 aluminum alloy accounts for 10-20%; or a single component aluminum alloy; or a two-layer or three-layer composite aluminum alloy or copper-aluminum composite material.

4. The method according to claim 1, characterized in that: In step 6, the injection tube is welded to the sintered semi-finished product using high frequency welding, or a brazing furnace is used for welding.

5. An aluminum temperature equalizing plate, characterized in that: The aluminum temperature equalizing plate is made by the manufacturing method of any one of claims 1 to 4, the aluminum temperature equalizing plate comprises an upper cover and a lower cover, a mesh capillary is arranged in the upper cover, an aluminum powder sintered layer is arranged on the inner side of the lower cover, a plurality of holes are evenly arranged in the aluminum powder sintered layer, the holes are used to install aluminum columns, a powder ring is sleeved on the aluminum column, the mesh capillary is composed of a plurality of 45° and 135° grooves staggered, the depth of the groove is 0.05-0.1mm, and the spacing between adjacent grooves is 0.05-0.1mm.

Images