Micro-channel structure manufacturing process

Abstract

The invention belongs to the technical field of metal forming machining, and provides a micro-channel structure manufacturing process which comprises the steps that channels are machined in the surface of a raw material plate, and a bottom plate is obtained; diffusing and welding a cover plate on the surface of the bottom plate to cover the bottom plate to obtain a first prefabricated plate; forming a groove in the surface of the first precast slab to obtain a second precast slab; pressing and forming the second precast slab by using a mold to obtain a third precast slab; and the groove in the surface of the third prefabricated plate is subjected to filling welding to obtain the micro-channel structure with the curved surface. Before compression molding, the grooves are formed in the surface of the first prefabricated plate on the outer side of the bending direction of the designed micro-channel structure, and the grooves can increase the extension degree of ribs between adjacent micro-channels, reduce the extension degree of the outer side walls of the micro-channels and even eliminate extension of the outer side walls of the micro-channels, so that the outer side walls of the micro-channels are prevented from being thinned; therefore, the wall thickness of the micro-channel is consistent, and the structural integrity and strength performance of the micro-channel are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of metal pressing and forming, and in particular relates to a microchannel structure manufacturing process. Background Art

[0002] Microchannel structure is a precision structure with tiny channels. It is widely used in heat exchangers, microreactors, etc. due to its high surface area to volume ratio, efficient heat and mass transfer capabilities and precise fluid control performance.

[0003] In the process of using a flat plate of a microchannel structure to press-form a curved microchannel structure with a certain curvature, since the microchannel is a hollow structure and the ribs between adjacent microchannels are solid structures, the arc extension of the outer side wall of the microchannel is much greater than the arc extension of the outer side of the rib, which in turn causes the outer side wall of the microchannel to become thinner or even crack, seriously affecting the strength performance of the microchannel.

[0004] Prior art CN119259790A discloses a manufacturing process for a variable curvature thin-wall microchannel structure, which compensates the length of the microchannel bottom, i.e., the outer side wall of the microchannel, so that it has sufficient stretchable distance during the pressing process to avoid thinning or cracking of the microchannel bottom.

[0005] However, the effect of this process in manufacturing continuously curved microchannel structures with larger curvature is still not ideal. Summary of the invention

[0006] The present invention provides a microchannel structure manufacturing process, aiming to solve the above technical problems.

[0007] The present invention is achieved in that a microchannel structure manufacturing process comprises the following steps:

[0008] Processing grooves on the surface of the raw material plate according to the number of microchannels of the designed microchannel structure to obtain a bottom plate;

[0009] A cover plate is diffusion welded on the surface of the bottom plate to cover the bottom plate, so as to obtain a first prefabricated plate, wherein the first prefabricated plate has microchannels, and ribs are provided between adjacent microchannels;

[0010] A groove is formed on the surface of the first prefabricated plate at the outer side of the bending direction of the designed microchannel structure to obtain a second prefabricated plate, wherein the length and position of the groove correspond to the ribs one by one;

[0011] Using a mold to press-form the second prefabricated board to obtain a third prefabricated board;

[0012] The groove on the surface of the third prefabricated plate is filled and welded flat to obtain a microchannel structure with a curved surface.

[0013] Furthermore, after the groove is formed, the thickness of the ribs of the second prefabricated plate is less than or equal to twice the wall thickness of the microchannel on the outer side of the bending direction of the designed microchannel structure.

[0014] Furthermore, the wall thickness of the inner side and the outer side of the microchannel are equal.

[0015] Furthermore, after the groove is formed, the width of the ribs between each microchannel and the groove is equal.

[0016] Furthermore, after the groove is formed, the width of the rib between the microchannel and the groove is equal to the wall thickness of the microchannel.

[0017] Furthermore, the groove bottom and the groove opening both have rounded corner structures.

[0018] Furthermore, the fillet radius of the fillet structure is 0.3 to 0.5 times the wall thickness of the microchannel.

[0019] Beneficial effects: The microchannel structure manufacturing process provided by the present invention splits the microchannel structure into a combined structure of a cover plate and a base plate, firstly processes a groove on the raw material plate to obtain the base plate, and then combines the cover plate and the base plate to obtain the microchannel structure through mold press molding. Before press molding, a groove is opened on the surface of the first prefabricated plate on the outside of the bending direction of the designed microchannel structure, that is, a groove is opened at the position of the rib, and the length and position of the groove correspond to the rib one by one, which is equivalent to a milling notch or a release groove. The groove can weaken the rib, increase the extension of the rib between adjacent microchannels, reduce the extension of the outer side wall of the microchannel, or even eliminate the extension of the outer side wall of the microchannel, and avoid the thinning of the outer side wall of the microchannel, so as to make the wall thickness of the microchannel consistent and ensure the structural integrity and strength performance of the microchannel. For curved microchannel structures with larger curvature and continuous curvature, the present invention can greatly reduce the thinning or cracking of the outer side wall of the microchannel during the press molding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of a curved microchannel structure.

[0021] Figure 2 It is a schematic diagram of the microchannel structure manufacturing process provided by an embodiment of the present invention.

[0022] Figure 3 This is an enlarged view of one end of the second precast panel.

[0023] Figure 4 It is a schematic structural diagram of a second prefabricated panel in another embodiment.

[0024] Figure 5 It is a schematic structural diagram of a third prefabricated panel in another embodiment.

[0025] Figure 6 is a schematic diagram of a microchannel structure of another embodiment.

[0026] Figure 7 It is a parameter diagram of diffusion welding of the base plate and the cover plate in the embodiment of the present invention.

[0027] The numbers in the figure respectively represent: 1-raw material plate, 2-groove, 3-bottom plate, 4-cover plate, 5-first prefabricated plate, 6-microchannel, 7-rib, 8-groove, 9-second prefabricated plate, 10-mold, 11-third prefabricated plate, 12-microchannel structure, a-wall thickness of microchannel, b-thickness of the rib of the remaining part, c-width of the rib between the microchannel and the groove. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] like Figure 1 As shown, the curved microchannel structure 12 with a large curvature has a plurality of microchannels 6. For the problems existing in the actual production of this structure, see Figure 2 , 3 The present invention provides a microchannel structure manufacturing process, which includes the following steps:

[0030] S1: machining grooves 2 on the surface of the raw material plate 1 according to the number of microchannels 6 of the designed microchannel structure 12 to obtain the bottom plate 3.

[0031] Before manufacturing the microchannel structure 12 with a curved surface, a model of the microchannel structure 12 with size parameters is pre-set, the size of the raw material plate 1 is determined according to the length, width and thickness of the model, and the grooves 2 having the same number as the microchannels are processed on the raw material plate 1.

[0032] S2: A cover plate is diffusion welded on the surface of the bottom plate 3 to cover the bottom plate 4, so as to obtain a first prefabricated plate 5, wherein the first prefabricated plate 5 has microchannels 6, and ribs 7 are arranged between adjacent microchannels 6.

[0033] The cover plate 4 covers each groove 2 on the bottom plate 2 , and the cover plate 4 is integrated with the protruding structures between adjacent grooves 2 by diffusion welding to form a first prefabricated plate 5 .

[0034] S3: A groove 8 is opened on the surface of the first prefabricated plate 5 on the outer side of the bending direction of the designed microchannel structure 12 to obtain a second prefabricated plate 9, and the length and position of the groove 8 correspond to the ribs 7 one by one.

[0035] The groove 8 is provided according to the bending direction of the microchannel structure 12 to be manufactured, so as to weaken the rib 7, increase the extension degree of the rib 7 during the pressing process, make the rib 7 more likely to extend during the pressing process, reduce the extension degree of the microchannel outer side wall or even eliminate the extension of the microchannel outer side wall, make the rib 7 and the microchannel outer side wall deformation degree tend to be consistent, so as to make the microchannel wall thickness consistent, and avoid the microchannel outer side wall from being thinned and cracked. The surface where the groove 8 is provided is selected to be the outer side of the bending direction, that is, the extension surface of the microchannel structure 12.

[0036] The size of the groove 8 is such that after the groove 8 is formed, the thickness of the rib 7 of the second prefabricated plate 9 is less than or equal to twice the wall thickness of the microchannel 6 on the outer side of the bending direction of the designed microchannel structure 12. Figure 3 As shown, if the wall thickness of the microchannel 6 is a, and the thickness of the remaining rib 7 after the groove 8 is formed is b, then b≤2a.

[0037] In addition, in the embodiment of the present invention, Figure 3 As shown, the wall thickness of the inner and outer sides of the microchannel 6 is equal, both a.

[0038] In order to ensure that the second prefabricated plate 9 is uniformly extended at all locations during the pressing process, after the grooves 8 are formed, the widths of the ribs 7 between each microchannel 6 and the grooves 8 are made equal.

[0039] At the same time, after the groove 8 is formed, the width of the rib 7 between the microchannel 6 and the groove 8 is equal to the wall thickness a of the microchannel 6. Figure 3 As shown, if the width of the rib 7 between the microchannel 6 and the groove 8 is c, then c=a.

[0040] In order to avoid stress concentration during the pressing process, such as Figure 3 As shown, the groove bottom and groove opening of the groove 8 are both provided with rounded corner structures. The rounded corner radius of the rounded corner structure is 0.3 to 0.5 times the wall thickness of the microchannel, that is, 0.3a to 0.5a.

[0041] S4: using the mold 10 to press-form the second prefabricated board 9 to obtain the third prefabricated board 11.

[0042] S5: Fill and weld the groove 8 on the surface of the third prefabricated plate 11 to obtain a micro-channel structure 12 with a curved surface.

[0043] After the pressing and forming, the groove 8 on the surface of the third prefabricated plate 11 is filled and leveled by laser welding or argon arc welding to obtain a microchannel structure 12 with a flat surface and a curved surface.

[0044] The following is a detailed description through specific embodiments.

[0045] Example 1

[0046] The embodiment of the present invention provides a microchannel structure manufacturing process, comprising the following steps:

[0047] Parts and tooling preparation: prepare the raw material plate and cover plate. The raw material plate and cover plate are made of 304 stainless steel, with a length and width of 90mm. The thickness of the cover plate is 1mm. The diffusion welding surface roughness of the cover plate is better than 0.8μm and the flatness is better than 0.01mm.

[0048] The thickness of the raw material plate is 3mm. 13 grooves with a width of 2mm and a depth of 2mm are equidistantly processed on the raw material plate. The spacing between adjacent grooves (the width of the ribs) is 5mm. The roughness of the diffusion welding surface of the raw material plate is better than 0.8μm, and the flatness is better than 0.01mm to obtain the base plate.

[0049] The base plate and cover plate are first chemically degreased, cleaned with tap water, electrochemically polished, cleaned with alkaline metal cleaner, cleaned with tap water, and blown dry.

[0050] The bottom plate and the cover plate are then surface-nickel plated, rinsed with tap water, cleaned with deionized water and rinsed multiple times, and dried for later use.

[0051] Before diffusion welding of the base plate and the cover plate, solder resist is applied to the surface of each welding tooling and dried for use.

[0052] Assemble the bottom plate and the cover plate so that the cover plate overlaps with the bottom plate, fix them at the seams around the cover plate and the bottom plate by argon arc spot welding, and then transfer the whole to the diffusion welding furnace. Figure 7 Vacuum diffusion welding was performed using the diffusion welding parameters shown to obtain a first prefabricated plate, in which the wall thickness of the microchannels was 1 mm.

[0053] The first prefabricated board is taken out of the oven after being cooled. A groove with a depth of 2 mm and a width of 3 mm is processed at the bottom surface of the first prefabricated board at the position corresponding to the rib. A rounded structure with a rounded corner radius of 0.5 mm is processed at the bottom and the groove of the groove to obtain a second prefabricated board.

[0054] The second prefabricated plate was heated to 900° C. in a heating furnace with protective gas, kept warm for 1 hour, and then placed in a C-shaped pressing mold with a bending angle of 136 degrees for pressing to obtain a third prefabricated plate.

[0055] The groove on the bottom surface of the third prefabricated plate is filled by laser welding to obtain a microchannel structure with a C-shaped curved surface, see Figure 2 .

[0056] Example 2

[0057] The embodiment of the present invention provides a microchannel structure manufacturing process, comprising the following steps:

[0058] Parts and tooling preparation: prepare the raw material plate and cover plate. The raw material plate and cover plate are made of 304 stainless steel, with a length and width of 90mm. The thickness of the cover plate is 1mm. The diffusion welding surface roughness of the cover plate is better than 0.8μm and the flatness is better than 0.01mm.

[0059] The thickness of the raw material plate is 3mm. 13 grooves with a width of 2mm and a depth of 2mm are equidistantly processed on the raw material plate. The spacing between adjacent grooves (the width of the ribs) is 5mm. The roughness of the diffusion welding surface of the raw material plate is better than 0.8μm, and the flatness is better than 0.01mm to obtain the base plate.

[0060] The base plate and cover plate are first chemically degreased, cleaned with tap water, electrochemically polished, cleaned with alkaline metal cleaner, cleaned with tap water, and blown dry.

[0061] The bottom plate and the cover plate are then surface-nickel plated, rinsed with tap water, cleaned with deionized water and rinsed multiple times, and dried for later use.

[0062] Before diffusion welding of the base plate and the cover plate, solder resist is applied to the surface of each welding tooling and dried for use.

[0063] Assemble the bottom plate and the cover plate so that the cover plate overlaps with the bottom plate, fix them at the seams around the cover plate and the bottom plate by argon arc spot welding, and then transfer the whole to the diffusion welding furnace. Figure 7 Vacuum diffusion welding was performed using the diffusion welding parameters shown to obtain a first prefabricated plate, in which the wall thickness of the microchannels was 1 mm.

[0064] The first prefabricated board is taken out of the oven after cooling. A groove with a depth of 2.5 mm and a width of 3 mm is processed at the bottom surface of the left half of the first prefabricated board corresponding to the ribs. A groove with a depth of 2.5 mm and a width of 3 mm is processed at the top surface of the right half of the first prefabricated board corresponding to the ribs. A rounded structure with a rounded corner radius of 0.5 mm is processed at the bottom and notch of the groove to obtain the second prefabricated board. Figure 4 .

[0065] The second prefabricated plate was heated to 900°C in a heating furnace with protective gas, kept at this temperature for 1 hour, and then placed in an S-shaped pressing mold with a bending angle of 136 degrees on both sides to obtain a third prefabricated plate. Figure 5 .

[0066] The grooves on the bottom surface of the left half and the top surface of the right half of the third prefabricated plate are filled by argon arc welding to obtain a microchannel structure with an S-shaped surface, see Figure 6 .

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A microchannel structure manufacturing process, characterized in that: The following steps are involved: Processing grooves on the surface of the raw material plate according to the number of microchannels of the designed microchannel structure to obtain a bottom plate; A cover plate is diffusion welded on the surface of the bottom plate to cover the bottom plate, so as to obtain a first prefabricated plate, wherein the first prefabricated plate has microchannels, and ribs are provided between adjacent microchannels; A groove is formed on the surface of the first prefabricated plate at the outer side of the bending direction of the designed microchannel structure to obtain a second prefabricated plate, wherein the length and position of the groove correspond to the ribs one by one; Using a mold to press-form the second prefabricated board to obtain a third prefabricated board; The groove on the surface of the third prefabricated plate is filled and welded flat to obtain a microchannel structure with a curved surface.

2. The microchannel structure manufacturing process according to claim 1, characterized in that: After the groove is formed, the thickness of the ribs of the second prefabricated plate is less than or equal to twice the wall thickness of the microchannel on the outer side of the bending direction of the designed microchannel structure.

3. The microchannel structure manufacturing process according to claim 2, characterized in that: The wall thickness of the inner and outer sides of the microchannel is equal.

4. The microchannel structure manufacturing process according to claim 2, characterized in that: After the groove is formed, the width of the ribs between each microchannel and the groove is equal.

5. The microchannel structure manufacturing process according to claim 4, characterized in that: After the groove is formed, the width of the rib between the microchannel and the groove is equal to the wall thickness of the microchannel.

6. The microchannel structure manufacturing process according to claim 2, characterized in that: The groove bottom and the groove opening of the groove both have rounded corner structures.

7. The microchannel structure manufacturing process according to claim 6, characterized in that: The fillet radius of the fillet structure is 0.3 to 0.5 times the wall thickness of the microchannel.

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