Integrated cold plate with embedded heat pipes and forming process method of integrated cold plate

Abstract

The invention discloses an integrated cold plate with embedded heat pipes and a forming process method of the integrated cold plate, and belongs to the technical field of antenna manufacturing, the forming method comprises the steps that a shell is machined to form a plurality of linear deep cavities, and the heat pipes and the deep cavities of the shell are assembled in a glue joint mode, and the specific steps are as follows: the heat pipes matched with the deep cavities in diameter are selected; coating the heat conduction paste on the outer wall of the heat pipe; and the heat pipe is screwed into the deep cavity, and curing is carried out after heat pipe gluing is completed. The integrated cold plate is mounted on the base, and the active device is mounted on the integrated cold plate to dissipate heat of the active device. The heat pipe is low in cost, high in reliability and easy to maintain and assemble, mass application of air cooling heat dissipation is accelerated, the heat dissipation requirement for high heat flux of a new-generation phased array radar core assembly is met, and it is guaranteed that the power performance of a new-generation weapon equipment is maximized.

Description

Technical Field

[0001] This invention patent relates to the field of antenna manufacturing technology, and in particular to a process method for forming heat pipes embedded in the housing of an active subarray. Background Technology

[0002] As a key component of radar, the antenna array is crucial for ensuring radar early warning and detection capabilities. Active subarrays are the basic units of the antenna array, responsible for amplifying, converting, transmitting, and distributing radar signals; their performance directly impacts the radar's effectiveness.

[0003] When antenna aperture is severely limited, increasing component power density can enhance radar power. However, excessively high power density can cause devices to overheat, leading to a sharp drop in radar transmit power and receive gain, thus hindering the full potential and performance of the radar.

[0004] Active components in electronic devices typically dissipate heat through conduction while attached to a metal casing. The main heat dissipation methods include liquid cooling and air cooling. Liquid cooling involves machining deep channels inside the metal casing and then circulating coolant through these channels to carry away heat. However, liquid cooling is costly, complex, and lacks flexibility due to the need for an additional liquid cooling source; furthermore, it requires high cleanliness of the channels and is difficult to manufacture.

[0005] Air cooling also involves machining deep holes inside the metal casing and then installing heat pipes inside the holes to carry away the heat. Traditional heat pipes are formed by induction brazing, which is a complex process with difficulty in detecting the solder penetration rate, poor manufacturability, and inability to effectively monitor and guarantee thermal conductivity. This has become a bottleneck restricting the large-scale application of air cooling. At the same time, air cooling also carries the risk of poor heat dissipation performance of active devices and failure to meet radar performance standards.

[0006] Based on the above problems, there is an urgent need to develop a new type of active subarray integrated cold plate forming process to achieve low-cost, high-reliability, and easy-to-maintain assembly of heat pipes, accelerate the mass application of air cooling, meet the heat dissipation requirements of high heat flux density of core components of the new generation of phased array radar, and ensure the maximum power performance of the new generation of weapons and equipment. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a simple process flow, low processing cost, and high reliability for embedding heat pipes in an active subarray shell and its forming process.

[0008] A method for forming an integrated cold plate with an embedded heat pipe includes the following steps: (1) Housing processing: Fins are provided on one side of the housing, and an active device fixing plate is provided on the other side. Several straight deep cavities are processed inside the housing, and the deep cavities are along the direction from the fins to the fixing plate. (2) Heat pipe bonding assembly: The heat pipe is assembled with the deep cavity of the shell by bonding. The specific steps are as follows: Select a heat pipe that matches the diameter of the deep cavity, apply thermal paste to the outer wall of the heat pipe; screw the heat pipe into the deep cavity, and cure the thermal paste after completing the heat pipe bonding. (3) Seal the heat pipe holes and then perform anti-corrosion treatment on the shell. (4) The active device is pressed and fixed on the active device mounting plate by the pressing device, and the housing is embedded in the base by the pressing device.

[0009] Furthermore, the shell after deep cavity machining is surface treated, and the shell after sealing the heat pipe holes is treated with anti-corrosion treatment.

[0010] Furthermore, the heat pipe is made of CU1020.

[0011] Furthermore, the diameter of the heat pipe is 0.1 mm smaller than the diameter of the deep cavity.

[0012] Furthermore, the housing material is selected from aluminum alloy, stainless steel, and titanium alloy.

[0013] Furthermore, the shell processing method is selected from CNC machining, die casting, and powder metallurgy.

[0014] Furthermore, the deep cavity machining method for the shell is selected from deep hole drilling and electrical discharge machining.

[0015] Furthermore, the surface treatment is selected from conductive oxidation, passivation, and anodic oxidation, and the anti-corrosion treatment is spray painting.

[0016] Furthermore, after curing, the cover plate is screwed to the housing to seal the heat pipe hole using countersunk locking screws, thus completing the seal.

[0017] An integrated cold plate with an embedded heat pipe is prepared using any of the aforementioned process methods. The heat generated by the active device is transferred to the heat pipe through the metal cold plate. The medium inside the heat pipe transfers heat through self-convection via an evaporation-condensation cycle. The heat pipe conducts heat to the fins to achieve heat dissipation.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) By bonding the heat pipe to the deep cavity of the shell in one step, the processing cycle is shortened, the manufacturing process is simplified, and the manufacturing difficulty is reduced; (2) Apply thermal paste evenly to the surface of the heat pipe in advance to improve the coating coverage and ensure thermal conductivity; (3) A 0.05mm gap is reserved on one side between the heat pipe and the deep cavity to ensure both the continuity of heat conduction and the ease of assembly of the heat pipe; (4) By slowly rotating and pushing instead of directly pushing in axially, the space filling rate of the thermal paste is improved, ensuring thermal conductivity; (5) The heat pipe hole is sealed by locking the cover plate with countersunk screws, which is simple to process and has strong environmental adaptability. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of an integrated cold plate with embedded heat pipe structure; Figure 2 This is a schematic diagram of the casing; Figure 3 This is a schematic diagram of the heat pipe embedded in the casing; Figure 4 This is a schematic diagram of an integrated cold plate with embedded heat pipes; Figure 5 This is a flowchart of the molding process.

[0020] Among them, 1 is the shell, 2 is the heat pipe, 3 is the active device mounting plate, 4 is the deep hole, 5 is the base, 6 is the clamping device, and 7 is the integrated cold plate. Detailed Implementation

[0021] The technical solution of the present invention will be further explained below with reference to the accompanying drawings. The scope of protection of the present invention is not limited to the following description: A manufacturing process for an integrated active subarray cold plate 7 with embedded heat pipes 2 includes the following steps: Aluminum alloy casing 1 roughing: according to the attached... Figure 1 The middle shell 1 structure is made of aluminum alloy blank and is formed by CNC machining; the end face dimensions are machined to the design dimensions with a 2mm precision machining allowance. Stress-relief annealing: Stress-relief annealing is performed on the rough-machined subarray shell 1 to eliminate residual stress; the temperature is raised to 570±10℃, and the heating rate does not exceed 120℃ / h; the workpiece is held at the temperature for 3-4h after reaching the temperature and then cooled in the furnace. Strength test: The tensile strength of the subarray shell 1 after heat treatment should be ≥206MPa; Surface finishing of aluminum alloy subarray housing 1: The end face of housing 1 is machined to the design dimensions by milling; complex features such as sealing grooves are machined by electrical discharge machining; Deep cavity machining: The shell's through hole 1 was machined to the designed size using a deep hole drilling machine; the through hole diameter was designed to be φ6.1mm. Additional features were designed during the process. Figure 2 The contouring fixture shown uses a pressure block to fix the sub-array housing 1 and ensure the straightness of the deep hole 4 drilling process; Release the clamping stress by loosening the contouring tooling, and perform online measurement in the natural state of shell 1 to ensure that the key dimensions (flatness, perpendicularity, etc.) are qualified; Conductive oxidation: Conductive oxidation treatment is performed on the aluminum alloy shell 1 after the deep hole 4 is machined to improve corrosion resistance, remove oil and debris from the product surface and inside the hole, and ensure the assembly reliability of heat pipe 2. Heat pipe 2 preparation: Select CU1020 heat pipe, diameter φ6mm, wall thickness 0.3mm, power 20W; Pre-process weighing: Weigh 1 unit of the cold plate shell (M). K- 2 heat pipes, weight M G And record it; Stirring and coating: Use a brush to stir the thermal paste (thermal conductivity 8.5W / m·K, thermal resistance ≤0.05℃·cm² / W) evenly and coat it evenly on the outer wall of heat pipe 2, ensuring that the coating is complete and without any omissions; Screwing in heat pipe 2: Screw heat pipe 2 into the through hole in a crisscross pattern of forward and reverse directions, rotating slowly as you go. Do not push it in axially directly. After heat pipe 2 is screwed in, there should be no excess glue on the housing 1, the end of heat pipe 2 should be sealed flat and should not protrude and affect the assembly of other parts on the end face. There should be no residual oil, impurities or other dirt on the surface of housing 1. Post-processing weighing: Weighing the integrated cold plate (7 M) after the heat pipe 2 is glued and assembled. + The amount of adhesive filler for the heat pipe 2 joint of the cold plate shell was calculated (accurate to one decimal place) in M. J = M + -M K- -M G The self-inspection glue volume record is complete. If the glue volume is significantly less than that of other parts (fluctuation amount ≥ 5% of the average), glue needs to be reapplied in time. Curing: The integrated cold plate 7 of the active subarray after the heat pipe 2 has been glued is left to stand naturally at room temperature for 24 hours to allow the thermal paste to fully cure. Sealing: Use countersunk locking screws to screw the small cover plate to the end face of the integrated cold plate 7 to seal the heat pipe hole and complete the sealing; the purpose of sealing is to ensure that there is no contamination inside the cold pipe, and also for aesthetic purposes; Spray painting: applying paint; Packaging: The tray and foam padding are used for protective packaging to avoid bumps and knocks, resulting in an integrated active subarray cold plate 7 with embedded heat pipe 2.

[0022] As attached Figure 1 As shown in the figure, it is a three-dimensional schematic diagram of the metal shell 1 after precision machining. The deep hole 4 in the figure is the installation position of the heat pipe 2, and the rear side is the position for mounting the active device. like Figure 2 As shown in the figure, the metal shell 1 is a rectangular body after rough machining.

[0023] like Figure 3 As shown in the figure, it is a two-dimensional schematic diagram of the location of the heat pipe 2 in the rough-machined metal shell 1. The long strip frame is the location of the deep hole 4 in the shell, which is also the installation location of the heat pipe 2.

[0024] In use, the pre-processed integrated cold plate 7 is installed on the base 5, and then used as follows: Figure 4The active device is also pressed and attached to the active device fixing plate 3 by the pressing device 6 and the pressure plate shown in the figure, with thermal conductive paste used on the contact surface.

[0025] Heat pipe 2 is filled with a suitable liquid with a low boiling point and high volatility. One end of heat pipe 2, the active device side, is the evaporation end, and the other end, the fin side, is the condensation end. When one end of heat pipe 2 is heated, the liquid in the capillary rapidly evaporates. The vapor flows to the other end under a small pressure difference, releasing heat, and then condenses back into liquid. The liquid then flows back to the evaporation section along the inside of heat pipe 2, and this cycle continues indefinitely, transferring heat from one end of heat pipe 2 to the other. This cycle is rapid, and heat can be continuously conducted, achieving self-circulating heat dissipation.

Claims

1. A method for forming an integrated cold plate with an embedded heat pipe, characterized in that: Includes the following steps: (1) Housing processing: Fins are provided on one side of the housing, and an active device fixing plate is provided on the other side. Several straight deep cavities are processed inside the housing, and the deep cavities are along the direction from the fins to the fixing plate. (2) Heat pipe bonding assembly: Select a heat pipe that matches the diameter of the deep cavity, apply thermal paste to the outer wall of the heat pipe, screw the heat pipe into the deep cavity, and cure the thermal paste after completing the heat pipe bonding. (3) Seal the heat pipe holes, (4) The active device is pressed and fixed on the active device mounting plate by the pressing device, and the housing is embedded in the base by the pressing device.

2. The integrated cold plate forming process for embedded heat pipes according to claim 1, characterized in that: The shell after deep cavity machining is surface treated, and the shell after sealing the heat pipe holes is treated with anti-corrosion treatment.

3. The integrated cold plate forming process for embedded heat pipes according to claim 1, characterized in that: The heat pipe is made of CU1020.

4. The integrated cold plate forming process for embedded heat pipes according to claim 1, characterized in that: The diameter of the heat pipe is 0.1 mm smaller than the diameter of the deep cavity.

5. The integrated cold plate forming process method for embedded heat pipes according to claim 1, characterized in that: The shell material is selected from aluminum alloy, stainless steel, and titanium alloy.

6. The integrated cold plate forming process for embedded heat pipes according to claim 1, characterized in that: The shell processing method is selected from CNC machining, die casting, and powder metallurgy.

7. The integrated cold plate forming process for embedded heat pipes according to claim 1, characterized in that: The deep cavity machining method for the shell is selected from deep hole drilling and electrical discharge machining.

8. The integrated cold plate forming process method for embedded heat pipes according to claim 2, characterized in that: The surface treatment is selected from conductive oxidation, passivation, and anodic oxidation, and the anti-corrosion treatment is spray painting.

9. The integrated cold plate forming process for embedded heat pipes according to claim 1, characterized in that: After curing is complete, use countersunk locking screws to screw the cover plate to the housing to seal the heat pipe holes, thus completing the seal.

10. An integrated cold plate with an embedded heat pipe, characterized in that, An integrated cold plate is prepared using any one of the process methods of claims 1 to 9. The heat generated by the active device is transferred to the heat pipe through the metal cold plate. The medium inside the heat pipe transfers heat through self-convection via an evaporation-condensation cycle. The heat pipe conducts heat to the fins to achieve heat dissipation.

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