A method for preparing gradient groove wick heat sink based on laser

Abstract

The present invention relates to the technical field of heat spreader processing, and specifically discloses a method for preparing a heat spreader with a gradient groove liquid wick based on laser, comprising: 1) placing a metal substrate on a rotating platform and setting a constant rotation direction and rotation rate; 2) while the rotating platform drives the metal substrate to rotate, using a pulsed laser to move toward the geometric center of the metal substrate at a certain rate, generating a vortex gradient groove through etching processing, and leaving a support column in the center to form a liquid reflux groove and a heat dissipation support column; 3) using a welding machine to weld two metal substrates with a gradient groove liquid wick structure so that the central support columns overlap with each other to form a heat spreader; this method for preparing a heat spreader with a gradient groove liquid wick based on laser not only shortens the preparation time and improves the preparation efficiency, but also has the convenience of product serialization production, providing strong support for achieving large-scale batch production.

Description

Technical Field

[0001] The present invention relates to the technical field of vapor chamber processing, and in particular to a method for preparing a vapor chamber with a gradient groove based on laser. Background Art

[0002] With the advancement of technology, efficient heat dissipation and heat distribution technologies are becoming increasingly important in electronics, optical equipment, and other fields. The gradient groove wick structure, an innovative design that integrates a rotating platform and pulsed laser fabrication technology to create vortex-shaped gradient grooves, provides a new solution for efficient heat dissipation and liquid recirculation.

[0003] The traditional method for preparing grooved liquid-absorbing cores has problems such as long time and low efficiency. Therefore, the present invention aims to provide a method for preparing gradient grooved liquid-absorbing core heat sinks by high-efficiency laser, which shortens the preparation time and improves the preparation efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for preparing a gradient groove liquid-absorbing core heat sink based on laser, which not only shortens the preparation time and improves the preparation efficiency, but also has the convenience of product serialization production, providing strong support for large-scale batch production.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions:

[0006] In a first aspect, an embodiment provides a method for preparing a gradient grooved vapor chamber based on laser, comprising the following steps:

[0007] 1) Place the metal substrate on a rotating platform and set a constant rotation direction and rotation speed;

[0008] 2) While the rotating platform drives the metal substrate to rotate, a pulsed laser is used to move toward the geometric center of the metal substrate at a certain rate, generating a vortex gradient groove through etching, and leaving a support column in the center to form a liquid reflux groove and a heat dissipation support column;

[0009] 3) Using a welding machine, weld the two metal substrates with gradient groove wick structures so that the central support columns overlap with each other to form a heat spreader.

[0010] In the laser-based method for preparing a gradient grooved vapor chamber provided in at least one embodiment of the present disclosure, an air channel is designed between the contact surface of the rotating platform and the metal substrate to promote air circulation and exchange.

[0011] The rotation direction of the rotating platform is always kept clockwise or counterclockwise.

[0012] The rotation rate of the rotating platform is kept constant, and the rotation rate is ≥1000 rpm and ≤3000 rpm.

[0013] In the method for preparing a gradient groove wick heat sink based on laser provided in at least one embodiment of the present disclosure, the speed at which the pulsed laser translates toward the geometric center of the metal substrate is ≥100 μm / s, and the speed at which the pulsed laser translates toward the geometric center of the metal substrate is ≤200 μm / s.

[0014] The pulse half-width of the pulse laser is ≤200ns, and the power of the pulse laser is ≤100W.

[0015] The frequency of the pulse laser is ≥1 kHz.

[0016] The spot diameter of the pulse laser is ≥1 μm, and the spot diameter of the pulse laser is ≤100 μm. The scanning speed of the pulse laser is ≥10 mm / s, and the number of scanning times of the pulse laser is ≥10 times.

[0017] The energy distribution of the pulse laser is Gaussian distribution or flat-top distribution.

[0018] In the laser-based method for preparing a gradient grooved vapor chamber provided in at least one embodiment of the present disclosure, the welding method is one of cold welding, resistance welding or laser welding.

[0019] In the laser-based method for preparing a gradient grooved vapor chamber provided in at least one embodiment of the present disclosure, the thickness of the metal substrate is ≥0.2 mm.

[0020] The material of the metal substrate is one of metal copper, metal aluminum or alloy.

[0021] In the laser-based method for preparing a gradient grooved liquid-absorbing core heat sink provided in at least one embodiment of the present disclosure, the horizontal cross-section of the vortex gradient groove is approximately a multi-stage annular circle with a low middle and high edges, and is distributed in a vortex shape.

[0022] The width of the vortex gradient groove is ≤200 μm, and the width of the vortex gradient groove is ≥100 μm.

[0023] The depth of the gradient groove structure is ≤1 mm, and the depth of the gradient groove structure is ≥0.5 mm.

[0024] The gradient angle of the gradient groove structure is ≤20°, and the gradient angle of the gradient groove structure is ≥5°, and the gradient angles of the vortex gradient grooves are smoothly connected.

[0025] The spacing between each two adjacent micro grooves in the vortex gradient groove is ≥100 μm, and the spacing between each two adjacent micro grooves in the vortex gradient groove is ≤200 μm.

[0026] In the laser-based method for preparing a gradient grooved vapor chamber provided in at least one embodiment of the present disclosure, the horizontal cross-section of the central support column is circular.

[0027] The diameter of the central support column is ≤5 mm, and the diameter of the central support column is ≥3 mm.

[0028] The thickness of the central support column is ≤2 mm, and the thickness of the central support column is ≥1.5 mm.

[0029] In a first aspect, embodiments provide a gradient groove wick comprising a metal substrate, a gradient groove structure, and a central support column. The gradient groove structure is located on the inner surface of the metal substrate and exhibits a vortex-like distribution with a low center and high edges. This design allows the liquid liquefied by hot steam to flow rapidly back from the higher edges to the lower central heating end by gravity, achieving rapid liquid reflux. Furthermore, the central support column, located at the geometric center of the metal substrate, provides support and heat conduction, thereby improving heat dissipation efficiency.

[0030] The thickness of the metal substrate is ≥0.2 mm;

[0031] The horizontal cross-section of the gradient groove structure resembles a multi-stage circular ring, with a low center and high edges, forming a vortex-like distribution. Liquid liquefied by the hot steam can flow rapidly from the higher edges back to the lower central heating end by gravity. A central support column with a circular horizontal cross-section is located at the center of the gradient groove wick, providing support and heat conduction. The gradient groove wick can be applied to heat sink microchannels, heat pipes, and vapor chambers.

[0032] The beneficial effects of the present invention are:

[0033] By using a rotating platform with a constant rotation direction and rotation rate, and by translating the pulsed laser toward the center of the metal substrate at a constant rate, the method cleverly utilizes the principle that the accumulated energy density of the pulsed laser varies at different locations on the metal substrate, successfully achieving a vortex-shaped gradient groove structure with shallower groove depths at the edges and deeper groove depths in the middle. After the hot vapor is liquefied, the liquid working fluid can use gravity to quickly flow back from the condensation end at the edge of the wick to the central evaporation end. This design cleverly utilizes gravity to accelerate the liquid return rate and improve the efficiency of heat dissipation, thereby making the heat dissipation and working fluid circulation process more efficient, helping to improve the temperature uniformity and heat dissipation efficiency of the heat spreader.

[0034] The processing utilizes a rotating platform and pulsed laser translation, which greatly shortens the processing time of the wick structure, improves the preparation efficiency of the wick and the heat spreader, and realizes large-scale batch production.

[0035] The preparation method is characterized by being easy to produce in series, thus providing convenience for production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 The present invention is a flow chart of a method for preparing a gradient grooved liquid wick heat sink based on laser.

[0038] Figure 2 Schematic diagram of the dimension marking of the gradient groove wick.

[0039] Figure 3 The figure is a comparison chart of the performance test of the heat sink of Example 1 and Comparative Example 1.

[0040] Figure 4 A comparison chart of the time required for processing the heat sinks of Preparation Example and Comparative Example 1.

[0041] Figure 5 Schematic diagram of the distribution of gradient grooves on the metal substrate.

[0042] Figure 6 Schematic diagram of the equipment layout for preparing gradient groove wicks.

[0043] In the picture:

[0044] 1. Pulsed laser;

[0045] 2. Metal substrate;

[0046] 3. Airway;

[0047] 4. Rotating platform;

[0048] 20. Gradient groove structure;

[0049] 30. Center support column. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments, rather than all the embodiments.

[0051] The embodiment provides a method for laser-based preparation of a gradient grooved liquid-absorbing core heat sink. The core idea is to use a rotating platform and a pulsed laser that translates toward the geometric center of the metal substrate to process gradient grooves with a low center and high edges and a vortex-shaped distribution on the metal substrate, and a central support column with support and heat transfer capabilities, thereby effectively increasing the speed of liquid reflux to the evaporation end and enhancing the heat dissipation efficiency.

[0052] The present invention provides a method for preparing a gradient grooved liquid wick heat sink based on laser, comprising the following steps:

[0053] 1) Place the metal substrate on a rotating platform and set a constant rotation direction and rotation speed;

[0054] 2) While the rotating platform drives the metal substrate to rotate, a pulsed laser is used to move toward the geometric center of the metal substrate at a certain rate, generating a vortex gradient groove through etching, and leaving a support column in the center to form a liquid reflux groove and a heat dissipation support column;

[0055] 3) Using a welding machine, weld the two metal substrates with gradient groove wick structures so that the central support columns overlap with each other to form a heat spreader.

[0056] In this embodiment, an air channel is designed between the contact surface of the rotating platform and the metal base to promote air circulation and exchange.

[0057] The direction of rotation of the rotating platform always remains clockwise or counterclockwise.

[0058] The rotation speed of the rotating platform is kept constant, with the rotation speed being ≥1000 rpm and the rotation speed being ≤3000 rpm.

[0059] In this embodiment, the speed at which the pulse laser translates toward the geometric center of the metal substrate is ≥100 μm / s, and the speed at which the pulse laser translates toward the geometric center of the metal substrate is ≤200 μm / s.

[0060] The pulse half-width of the pulse laser is ≤200ns, and the power of the pulse laser is ≤100W.

[0061] The frequency of the pulsed laser is ≥1kHz.

[0062] The spot diameter of the pulse laser is ≥1 μm, and the spot diameter of the pulse laser is ≤100 μm, the scanning speed of the pulse laser is ≥10 mm / s, and the number of scanning times of the pulse laser is ≥10 times.

[0063] The energy distribution of the pulsed laser is Gaussian distribution or flat-top distribution.

[0064] In this embodiment, the welding method is one of cold welding, resistance welding, or laser welding. It is understood that those skilled in the art may select different welding methods according to actual needs.

[0065] In this embodiment, the thickness of the metal substrate is ≥0.2 mm, and the material of the metal substrate is copper, aluminum, or an alloy.

[0066] Preferably, the metal base is made of copper, which has low thermal resistance, good dielectric compatibility, and excellent stability, and can be used stably for a long time. The size of the metal base is 70*70*2mm 3 of copper sheets.

[0067] In this embodiment, the diameter of the central support column of the gradient groove wick structure is as follows: Figure 2 As shown in d1; the width of the gradient groove is as Figure 2 As shown in d2; the width between each two adjacent micro grooves is as Figure 2 As shown in d3; the thickness of the central support column is as Figure 2 As shown in h1; the depth of the groove is as Figure 2 As shown in h2.

[0068] Specifically, the horizontal cross-sectional shape of the vortex gradient groove is approximately a multi-stage annular circle, which is low in the middle and high at the edges, and is distributed in a vortex shape.

[0069] Specifically, the width of the vortex gradient groove is ≤200 μm, and the width of the vortex gradient groove is ≥100 μm.

[0070] Specifically, the depth of the gradient groove structure is ≤1 mm, and the depth of the gradient groove structure is ≥0.5 mm.

[0071] Specifically, the gradient angle of the gradient groove structure is ≤20°, and the gradient angle of the gradient groove structure is ≥5°, and the gradient angles of the vortex gradient grooves are smoothly connected.

[0072] Specifically, the distance between every two adjacent micro grooves in the vortex gradient groove is ≥100 μm, and the distance between every two adjacent micro grooves in the vortex gradient groove is ≤200 μm.

[0073] Specifically, the horizontal cross-section of the central support column is circular.

[0074] Specifically, the diameter of the central support column is ≤5 mm, and the diameter of the central support column is ≥3 mm.

[0075] Specifically, the thickness of the central support column is ≤2 mm, and the thickness of the central support column is ≥1.5 mm.

[0076] like Figure 5As shown, the present invention also provides a gradient groove wick comprising a metal substrate 2, a gradient groove structure 20, and a central support column 30. The gradient groove structure 20 is located on the inner surface of the metal substrate 2 and exhibits a vortex-like distribution with a low center and high edges. This design allows the liquid liquefied by hot steam to flow rapidly back from the higher edges to the lower central heating end by gravity, achieving rapid liquid reflux. Furthermore, the central support column 30, located at the geometric center of the metal substrate 2, provides support and heat conduction, thereby improving heat dissipation efficiency.

[0077] The following will be described with specific examples and comparative examples. It should be noted that if there are any processes not specifically described below, they can be implemented or understood by those skilled in the art with reference to the prior art.

[0078] Example

[0079] like Figure 1 and 6 As shown, the method for preparing a gradient groove vapor chamber based on laser in this embodiment specifically includes the following steps:

[0080] 1) The groove 6 is obtained by etching the surface of the metal substrate 2 by the pulse laser 1 in the air; the groove center support column 30 is obtained on the surface of the metal substrate 2 after the pulse laser 1 stops etching.

[0081] An air channel 3 is designed between the contact surface of the rotating platform and the metal base to promote the circulation and exchange of air.

[0082] The rotating platform 4 rotates in a clockwise direction at a rotation rate of 2000 rpm.

[0083] Among them, the scanning parameters of the pulse laser 1 are: the translation rate of the laser pulse 1 to the geometric center of the metal substrate 2 is 150μm / s, the half-maximum width is 10ps, the repetition frequency is 200kHz, the power is 25W, the focus spot diameter is 30μm, the scanning speed of the focus spot is 1200mm / s, and the number of scans of the focus spot is 15 times; the horizontal cross-sectional shape of the processed gradient groove wick structure is approximately a multi-stage annular circle, the groove width is 150μm, the depth is 1mm, and the shape is elliptical. The maximum gradient angle of the gradient groove structure is 18° and the minimum is 5°. The closer to the edge, the larger the gradient angle. The width between each two adjacent micro-grooves is 150μm; the horizontal cross-sectional shape of the central support column is circular, the diameter of the central support column is 5mm, and the thickness of the central support column is 1.5mm;

[0084] 3) Laser welding is used to weld two copper substrates with gradient groove structures together, a certain amount of deionized water is injected into them, and secondary evacuation and sealing are performed to form a heat spreader with a gradient groove wick structure. The cross-sectional view of the processed gradient groove wick model is shown in the figure. Figure 4 shown.

[0085] Comparative Example 1

[0086] This example was prepared by referring to the preparation method of the embodiment. The difference between this example and the embodiment is that the pulse laser continuously processes the metal substrate without leaving the metal support column. Other specific processing parameters remain unchanged. The support capacity and thermal conductivity of the liquid wick structure without a central support column are reduced, which increases the thermal resistance of the heat spreader of the comparative example 1. The thermal resistance test results of the heat spreader of the comparative example 1 and the embodiment are shown as follows: Figure 3 shown.

[0087] Comparative Example 2

[0088] This example was prepared by referring to the preparation method of the embodiment. The difference between this example and the embodiment is that: this example does not use a rotating platform for processing, and other specific processing parameters remain unchanged. The processing time of this liquid wick preparation method is greatly increased, which reduces the efficiency of preparing the liquid wick and the heat plate. The processing time of the comparative example 2 and the embodiment is as follows: Figure 4 shown.

[0089] Although the embodiments of the present application have been shown and described above, the scope of protection of the present invention is not limited thereto, and any changes or substitutions that are not conceivable through creative work should be included in the scope of protection of the present invention; unless expressly stated, any elements, actions or instructions used in this document should not be interpreted as critical or necessary.

Claims

1. A method for preparing a gradient groove wick heat sink based on laser, characterized in that: The following steps are involved: 1) Place the metal substrate on a rotating platform and set a constant rotation direction and rotation speed; 2) While the rotating platform drives the metal substrate to rotate, a pulsed laser is used to move toward the geometric center of the metal substrate at a certain rate, generating a vortex gradient groove through etching, and leaving a support column in the center to form a liquid reflux groove and a heat dissipation support column; 3) Use a welding machine to weld two metal substrates with gradient groove wick structures so that the central support columns overlap with each other to form a heat spreader; An air channel is designed between the contact surface of the rotating platform and the metal base to promote air circulation and exchange; The rotation direction of the rotating platform is always kept clockwise or counterclockwise; The rotation speed of the rotating platform is kept constant, the rotation speed is ≥1000 rpm and the rotation speed is ≤3000 rpm; The speed at which the pulsed laser translates toward the geometric center of the metal substrate is ≥100 μm / s, and the speed at which the pulsed laser translates toward the geometric center of the metal substrate is ≤200 μm / s; The pulse half-width of the pulse laser is ≤200ns, and the power of the pulse laser is ≤100W; The frequency of the pulsed laser is ≥1kHz; The spot diameter of the pulse laser is ≥1 μm, and the spot diameter of the pulse laser is ≤100 μm, the scanning speed of the pulse laser is ≥10 mm / s, and the number of scanning times of the pulse laser is ≥10 times; The energy distribution of the pulse laser is Gaussian distribution or flat-top distribution.

2. The method for preparing a gradient grooved liquid wick heat sink based on laser according to claim 1, characterized in that: The welding method is one of cold welding, resistance welding or laser welding.

3. The method for preparing a gradient grooved liquid wick heat sink based on laser according to claim 2, characterized in that: The thickness of the metal substrate is ≥0.2 mm; The material of the metal substrate is one of metal copper, metal aluminum or alloy.

4. The method for preparing a gradient grooved liquid wick heat sink based on laser according to claim 3, characterized in that: The horizontal cross-section of the vortex gradient groove is approximately a multi-stage annular circle, with a low center and high edges, and is distributed in a vortex shape; The width of the vortex gradient groove is ≤ 200 μm, and the width of the vortex gradient groove is ≥ 100 μm; The depth of the gradient groove structure is ≤1 mm, and the depth of the gradient groove structure is ≥0.5 mm; The gradient angle of the gradient groove structure is ≤20°, and the gradient angle of the gradient groove structure is ≥5°; The spacing between each two adjacent micro grooves in the vortex gradient groove is ≥100 μm, and the spacing between each two adjacent micro grooves in the vortex gradient groove is ≤200 μm.

5. The method for preparing a gradient grooved liquid wick heat sink based on laser according to claim 4, characterized in that: The horizontal cross-section of the central support column is circular; The diameter of the central support column is ≤5mm, and the diameter of the central support column is ≥3mm; The thickness of the central support column is ≤2 mm, and the thickness of the central support column is ≥1.5 mm.

Images