Fabricating heat sink

Abstract

The invention relates to a method for producing a heat sink (1). In the method, a main body (3) is first produced which has at least one main cooling channel (5, 7) which extends from a first outer surface (9) of the main body (3) to a second outer surface (11) of the main body (3) opposite the first outer surface (9). Then, at least one auxiliary cooling channel (17, 19) is produced in the body (3) by friction stir grooving, which auxiliary cooling channel is connected to the at least one main cooling channel (5, 7), and the at least one main cooling channel (5, 7) is closed on at least one outer surface (9, 11) of the body (3).

Description

Technical Field

[0001] The invention relates to a method for manufacturing a heat sink. Background Art

[0002] Heat sinks are primarily used to cool electronic components. In the case of such components, heat is generated during operation and must be dissipated to prevent the component from overheating. Such heat sinks usually have an internal channel structure, wherein a cooling fluid flows through the cooling channels to dissipate the heat. Such heat sinks are expensive to manufacture and usually require several different manufacturing steps.

[0003] For example, to produce the heat sink, the channel structure is first milled out in the body, which is then closed with a cover which is then connected to the body in a sealed and mechanically stable manner by vacuum brazing. Alternatively, for example, the channel structure is first milled out and the cooling pipe is then inserted into the channel structure.

[0004] In another method for producing a heat sink, for example, a body with mutually parallel cooling channels is first produced by extrusion. These parallel cooling channels are then connected by means of transversely extending holes. These holes are usually produced by a complex process for precisely drilling holes with a very large hole length to hole diameter ratio. Subsequently, the parallel cooling channels and the holes are closed from the outside by means of plugs. The plugs are therefore screwed in, for example, by means of threads, and the threads are additionally sealed with thread glue.

[0005] DE 10 2020 005 113 A1 discloses a component arrangement for a motor vehicle, the component arrangement having a first component and a second component, the first component and the second component being connected to each other in a material connection manner by a material connection device, so that a space through which a fluid can flow is formed between the components, and the space is sealed from the surrounding fluid of the component arrangement by the components and the material connection device. The material connection device comprises a first material connection element manufactured by a first connection method, and a second material connection element manufactured by a second connection method different from the first connection method.

[0006] Kush P. Mehta et al.: “A Review of Friction Stir-Based Channeling”, Solid State and Materials Science Reviews, Vol. 47, No. 1, pp. 1-45, DOI: 10.1080 / 10408436.2021.1886042, is a review article on the so-called friction stir groove forming.

[0007] WO 2017 / 220863 A1 discloses a rotatable and freely movable tool for producing a channel and a welded connection in a single working step. The tool comprises a shoulder and a probe, wherein the shoulder has a surface facing the material or materials of the component to be processed. The shoulder and the probe are arranged to act simultaneously and synchronously in the material of at least two components to be processed.

[0008] JP H11 47961 A discloses a tool in which a probe with a circumferential thread is provided which protrudes at the tip of a rotor. The tool moves over a metal plate, wherein a cavity is formed in the plate.

[0009] EP 3 723 463 A1 discloses a heat exchanger comprising a base plate having a first side and a second side opposite to the first side. The first side is designed to be coupled to a thermosyphon, and the base plate comprises a two-phase heat distribution structure.

[0010] CN 107 452 699 A discloses a liquid cooling plate for an IGBT module and a manufacturing method thereof. The liquid cooling plate comprises a base plate in which a plurality of liquid flow grooves parallel to each other are formed, and a cooling liquid for cooling the IGBT module flows through the liquid flow grooves. Summary of the invention

[0011] The object of the present invention is to provide an improved, in particular simplified, method for producing a heat sink having a cooling channel structure.

[0012] According to the invention, this object is achieved by a method having the features of claim 1 , a heat sink having the features of claim 9 , and an electronic component having the features of claim 10 .

[0013] Advantageous embodiments of the invention are the subject matter of the dependent claims.

[0014] In the method for manufacturing a heat sink according to the present invention, a body having at least one main cooling channel is first manufactured, the main cooling channel extending from a first outer surface of the body to a second outer surface of the body opposite to the first outer surface. In particular, a body having a plurality of mutually parallel main cooling channels can be manufactured, each main cooling channel extending from the first outer surface to the second outer surface. Then, at least one auxiliary cooling channel is generated in the body by friction stir grooving, the auxiliary cooling channel is connected to the at least one main cooling channel, and the at least one main cooling channel is closed at at least one outer surface of the body.

[0015] Therefore, the method according to the present invention provides that the cooling channel structure of the radiator is partially produced by so-called friction stir slotting. So-called friction stir slotting is a variant of the well-known so-called friction stir welding (Friction Stir Welding), also known as stir friction welding (Rührreibschweißen) or friction stir welding (Reibrührschweißen) in German. In friction stir welding, the gap is welded or closed by pressing a rotating tool into the gap. Due to the rotation, the material around the tool heats up and softens, but does not melt. The tool then moves along the gap so that the gap is closed with the softened material. In friction stir slotting, the rotating tool is designed and moved so that a channel or cavity is generated in the workpiece. Therefore, friction stir slotting can also be called stir friction channelization or friction stir channelization. In friction stir slotting, the channel generated in the workpiece or the cavity generated in the workpiece can also be closed at the same time, so that a channel closed to the outside is generated inside the workpiece. Friction stir slotting can therefore produce cooling channels in the radiator simply and cost-effectively, in particular without the need for costly cutting or vacuum brazing processes.

[0016] In an embodiment of the method according to the invention, at least one main cooling channel is closed at at least one outer surface of the body by friction stir welding. To this end, at least one further closing component can be used, which is connected to the body by friction stir welding. This embodiment of the invention uses friction stir welding to close the main cooling channel, thereby advantageously combining friction stir grooving and friction stir welding for the manufacture of the cooling channel structure.

[0017] In a further embodiment of the method according to the invention, the main body is formed by extrusion or compression molding. This further reduces the costs of manufacturing the heat sink, because the main body and its main cooling channels can be manufactured particularly cost-effectively by extrusion or compression molding.

[0018] The body is made of a thermoplastic resin such as acrylonitrile butadiene styrene (ABS), polyamide (PA), polylactic acid (PLA), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyetheretherketone (PEEK), or polyvinyl chloride (PVC).

[0019] The above materials are particularly suitable for friction stir grooving and are therefore suitable for manufacturing heat sinks according to the method of the present invention.

[0020] In another embodiment of the method according to the invention, at least two main cooling channels have cross sections that are different from each other and / or at least two auxiliary cooling channels have cross sections that are different from each other. By selecting suitable, mutually coordinated cooling channel cross sections, the cooling effect of the channel structure can be advantageously optimized.

[0021] In another embodiment of the method according to the present invention, at least a portion of the auxiliary cooling channel and the main cooling channel form a channel of a pulsating heat pipe. A pulsating heat pipe (English: Pulsating Heat Pipe, abbreviated: PHP), also known as an oscillating heat pipe (English: Oscillating Heat Pipe), usually has an elongated channel with multiple bends, which is partially filled with liquid. Since the liquid does not completely fill the volume of the channel, in the channel, due to the surface tension of the liquid, a liquid area filled with liquid is formed on the wall of the channel, and the liquid areas are separated from each other by steam areas formed by steam. Due to the temperature difference between different parts of the heat pipe, the liquid area will pulsate or oscillate, thereby achieving heat transfer and temperature compensation between these parts. The method according to the present invention is particularly suitable for manufacturing a radiator with a pulsating heat pipe.

[0022] The heat sink according to the invention is manufactured by the method according to the invention.

[0023] The electronic component according to the present invention has the heat sink according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The above characteristics, features and advantages of the present invention and the methods for achieving these will be more clearly understood and easily understood through the following description of the embodiments, which will be further described in conjunction with the accompanying drawings.

[0025] Figure 1 shows a flow chart of an embodiment of a method according to the present invention,

[0026] Figure 2 shows a cross-sectional view of an embodiment of a heat sink,

[0027] Figure 3 shows a side view of an embodiment of an electronic assembly,

[0028] Figure 4 Shown in Figure 3 A cross-sectional view of the electronic assembly shown in FIG.

[0029] Corresponding parts are provided with the same reference numerals in the figures. DETAILED DESCRIPTION

[0030] Figure 1A flow chart of an exemplary embodiment of a method according to the invention is shown, the method having method steps 101 , 102 , 103 for producing a heat sink 1 .

[0031] Method steps 101, 102, 103 are also referred to below. Figure 2 describe.

[0032] Figure 2 An embodiment of a heat sink 1 produced by the method according to the invention is shown.

[0033] In a first method step 101, a body 3 is produced with mutually parallel main cooling channels 5, 7, which extend from a first outer surface 9 of the body 3 to a second outer surface 11 of the body 3 opposite the first outer surface 9. Figure 2 In the embodiment shown, the body 3 has five main cooling channels 5, 7, wherein the two first main cooling channels 5 have the same cross section and the three second main cooling channels 7 also have the same cross section, but the cross section of the second main cooling channels is smaller than the cross section of the first main cooling channels 5. The first main cooling channel 5 is connected to the inlet 13 of the radiator 1 for introducing the coolant. The second main cooling channel 7 is connected to the outlet 15 of the radiator 1 for discharging the coolant.

[0034] The main body 3 is formed, for example, by extrusion or pressing.

[0035] The body 3 is made of a thermoplastic resin, for example, acrylonitrile butadiene styrene, polyamide, polylactic acid (polylactate), polymethyl methacrylate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyetheretherketone, or polyvinyl chloride.

[0036] In a second method step 102, auxiliary cooling channels 17, 19 are produced by friction stir grooving, which auxiliary cooling channels respectively connect at least two main cooling channels 5, 7. Figure 2 In the illustrated embodiment, the auxiliary cooling channels 17, 19 extend perpendicularly to the main cooling channels 5, 7. Thus, similar first auxiliary cooling channels 17 respectively connect two first main cooling channels 5 to each other. The first auxiliary cooling channels 17 form a plurality of auxiliary cooling channel groups 21 spaced apart from each other, each auxiliary cooling channel group having a plurality of first auxiliary cooling channels 17. The second auxiliary cooling channels 19 respectively connect the first main cooling channel 5 with at least one second main cooling channel 7, or the second auxiliary cooling channel connects at least two second main cooling channels 7. The first auxiliary cooling channel 17 has a smaller cross-section than the cross-section of the second auxiliary cooling channel 19. Preferably, the auxiliary cooling channels 17, 19 produced by friction stir grooving are also closed by friction stir grooving, so that no opening is formed on the outside of the main body 3 due to friction stir grooving.

[0037] In a third method step 103, the main cooling channels 5, 7 are closed at the outer surfaces 9, 11 except for the inlet 13 and the outlet 15. For example, the main cooling channels 5, 7 are closed by friction stir welding. Figure 2 The weld seam 23 produced thereby is shown in . If openings were formed on the outside of the body 3 by friction stir grooving in the second method step 102 and these openings have not yet been closed by friction stir grooving, these openings will also be closed in the third method step 103, for example also by friction stir welding.

[0038] Figure 3 and Figure 4 An embodiment of an electronic assembly 30 having a heat sink 1 is shown, which is realized and manufactured like the heat sink 1 shown in FIG. 2 . Figure 3 A side view of an electronic assembly 30 is shown. The electronic assembly 30 has a plurality of electronic components 32, 34. For example, the first electronic component 32 is a semiconductor switch such as an IGBT (IGBT: Insulated-Gate Bipolar Transistor), and the second electronic component 34 is a capacitor. The electronic components 32, 34 are arranged on a base plate 36 adjacent to the heat sink 1. Figure 4 A cross-sectional view of an electronic component 30 is shown, wherein the cutting plane is as shown in FIG. Figure 2 It is shown passing through the heat sink 1. Figure 4 The positions of the electronic components 32, 34 relative to the main cooling channels 5, 7 and the auxiliary cooling channels 17, 19 are indicated by dashed lines. The auxiliary cooling channel groups 21 are arranged in regions corresponding to the positions of the first electronic components 32. The second main cooling channel 7 extends in a region corresponding to the position of the second electronic component 34.

[0039] Although the present invention has been described in detail through preferred embodiments, the present invention is not limited to the disclosed embodiments, and a person skilled in the art can derive other variations therefrom without exceeding the protection scope of the present invention.

Claims

1. A method for manufacturing a heat sink (1), wherein: - a body (3) made of a thermoplastic resin, the body having at least one main cooling channel (5, 7), the main cooling channel extending from a first outer surface (9) of the body (3) to a second outer surface (11) of the body (3) opposite to the first outer surface (9), - producing at least one auxiliary cooling channel (17, 19) in the body (3) by friction stir grooving, the auxiliary cooling channel being connected to at least one of the main cooling channels (5, 7), and At least one of the main cooling channels (5, 7) is closed on at least one outer surface (9, 11) of the body (3).

2. The method according to claim 1, wherein: The main body (3) is provided with a plurality of mutually parallel main cooling channels (5, 7), each of which extends from the first outer surface (9) to the second outer surface (11) of the main body (3).

3. The method according to claim 1 or 2, wherein: At least one of the main cooling channels (5, 7) is closed on at least one outer surface (9, 11) of the main body (3) by means of friction stir welding.

4. A method according to any one of the preceding claims, wherein: The body (3) is produced by means of pressing or extrusion.

5. A method according to any one of the preceding claims, wherein: The main body (3) is made of acrylonitrile butadiene styrene, polyamide, polylactic acid ester, polymethyl methacrylate, polycarbonate, polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyether ether ketone or polyvinyl chloride.

6. A method according to any one of the preceding claims, wherein: At least two of the main cooling channels (5, 7) have cross sections that are different from each other.

7. A method according to any one of the preceding claims, wherein: At least two of the auxiliary cooling channels (17, 19) have cross sections that are different from each other.

8. A method according to any one of the preceding claims, wherein: The auxiliary cooling channel (17, 19) and at least a portion of the main cooling channel (5, 7) form a channel of a pulsating heat pipe.

9. A heat sink (1) manufactured using the method according to any one of the preceding claims.

10. An electronic component (30) comprising the heat sink (1) according to claim 9.

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