A manufacturing process for a variable curvature thin-wall microchannel structure

Abstract

The present invention belongs to the technical field of metal forming and processing, and provides a manufacturing process for a variable curvature thin-walled microchannel structure, including processing a groove on the front of a raw material plate to obtain a bottom plate, wherein the groove has an arc-shaped raised groove bottom; diffusion welding a cover plate on the front of the bottom plate to cover the bottom plate to obtain a first prefabricated plate; processing the back of the first prefabricated plate so that the bottom of the groove has a groove with the same shape as the arc-shaped raised groove bottom to obtain a second prefabricated plate; and die-pressing the second prefabricated plate to obtain a variable curvature thin-walled microchannel structure. The present invention splits the thin-walled microchannel structure into a combined structure of a cover plate and a bottom plate, and after the cover plate and the bottom plate are combined, a variable curvature thin-walled microchannel structure is obtained by die pressing. There is a groove on the bottom plate, and arc compensation is performed on the groove of the bottom plate by setting an arc-shaped raised groove bottom according to the different curvatures of the bottoms of each microchannel of the variable curvature thin-walled microchannel structure. The present invention can ensure that the wall thickness of the bottom of the microchannel is consistent and avoid cracking during the pressing process.

Description

Technical Field

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

[0002] The variable curvature thin-walled microchannel structure can theoretically be manufactured by pressing and molding a flat plate part after processing the microchannel. However, in actual production, the surface of the structure after pressing and molding often leads to inconsistent wall thickness at the bottom of the microchannel due to inconsistent elongation on both sides of the structure. Especially for a variable curvature thin-walled microchannel structure with a large length perpendicular to the bottom of the microchannel, after large curvature extension, the bottom of the microchannel may even be thinned or cracked, which seriously affects the strength performance of the microchannel.

[0003] Therefore, how to ensure that the wall thickness of the bottom of the microchannel of the variable curvature thin-walled microchannel structure remains consistent after press forming and ensure the structural strength of the microchannel is a technical problem to be solved in this field. Summary of the invention

[0004] The present invention provides a manufacturing process for a thin-wall microchannel structure with variable curvature, aiming to solve the above technical problems.

[0005] The present invention is achieved by a variable curvature thin-wall microchannel structure manufacturing process, comprising the following steps:

[0006] A groove is processed on the front side of the raw material plate according to the number of microchannels of the designed variable curvature thin-wall microchannel structure to obtain a bottom plate, wherein the groove has an arc-shaped convex groove bottom;

[0007] Diffusion welding a cover plate on the front side of the bottom plate to cover the bottom plate, so as to obtain a first prefabricated plate;

[0008] Processing the back side of the first prefabricated plate so that the bottom of the channel has a groove having the same shape as the bottom of the arc-shaped raised groove, thereby obtaining a second prefabricated plate;

[0009] Using a mold to press-form the second prefabricated plate to obtain a variable curvature thin-wall microchannel structure;

[0010] The arc length of the arc-shaped raised groove bottom of the groove is equal to the arc length of the outer side of the microchannel of the variable curvature thin-wall microchannel structure designed at the corresponding position.

[0011] Furthermore, the arc length of the arc-shaped raised groove bottom is positively correlated with the arc length of the outer side of the microchannel of the designed variable curvature thin-walled microchannel structure.

[0012] Furthermore, the number of the arc-shaped protrusions at the bottom of the arc-shaped protrusion groove is positively correlated with the curvature of the profile of the outer side of the microchannel of the designed variable curvature thin-wall microchannel structure.

[0013] Furthermore, adjacent arc-shaped protrusions transition smoothly in an arc shape.

[0014] Furthermore, the wall thickness of each part of the bottom of the arc-shaped raised groove on the second prefabricated plate is equal.

[0015] Furthermore, the width of the channel is equal to the distance between the midpoints of the two side walls of the designed microchannel as the curvature changes.

[0016] The manufacturing process of the variable curvature thin-walled microchannel structure provided by the present invention splits the thin-walled microchannel structure into a combined structure of a cover plate and a bottom plate, and the cover plate and the bottom plate are combined and then pressed into shape by a mold to obtain the variable curvature thin-walled microchannel structure. A groove is provided on the bottom plate, and arc compensation is performed on the groove of the bottom plate by setting an arc-shaped raised groove bottom according to the different curvatures of the bottoms of the microchannels of the variable curvature thin-walled microchannel structure. The present invention can ensure that the metal extension degree at the bottom of the microchannel is consistent, thereby making the wall thickness consistent and avoiding cracking during the pressing and forming process. In addition, the present invention can greatly reduce the situation of bottom thinning or cracking for large curvature pressing and forming of a variable curvature thin-walled microchannel structure with a large length in a direction perpendicular to the bottom of the microchannel. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of a variable curvature thin-walled microchannel part.

[0018] Figure 2 It is a schematic diagram of a manufacturing process of a variable curvature thin-wall microchannel structure provided by an embodiment of the present invention.

[0019] Figure 3 It is a marked diagram of the arc surface length of the arc-shaped raised groove bottom.

[0020] Figure 4 It is a marked diagram of the arc length on the outside of the microchannel of the designed variable curvature thin-wall microchannel structure.

[0021] Figure 5 It is a schematic diagram of the wall thickness of the bottom of an arc-shaped raised groove on the second prefabricated plate.

[0022] Figure 6 It is a schematic diagram of the wall thickness of the bottom of an arc-shaped raised groove on another second prefabricated plate.

[0023] Figure 7 4 is a diffusion welding parameter diagram of the base plate and the cover plate in the embodiment of the present invention.

[0024] The numbers in the figure respectively represent: 01-microchannel, 1-raw material plate, 2-bottom plate, 3-arc-shaped raised groove bottom, 4-cover plate, 5-first prefabricated plate, 6-groove, 7-second prefabricated plate, 8-mold; l1, l2, l3, l4, l5, l6, l7, l8, l9, l10, l11, l12-arc length of the arc-shaped raised groove bottom of each groove; L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12-arc length of the outer side of the microchannel of the designed variable curvature thin-walled microchannel structure. DETAILED DESCRIPTION

[0025] 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.

[0026] like Figure 1 As shown, the variable curvature thin-walled microchannel structure has multiple microchannels 01. For the problems existing in the actual production of this structure, see Figures 2 to 7 The embodiment of the present invention provides a manufacturing process of a variable curvature thin-wall microchannel structure, the process comprising the following steps:

[0027] S1: According to the designed number of microchannels of the variable curvature thin-wall microchannel structure, grooves are processed on the front side of the raw material plate 1 to obtain a bottom plate 2, wherein the grooves have an arc-shaped raised groove bottom 3.

[0028] Before manufacturing a variable curvature thin-walled microchannel structure, a model of the variable curvature thin-walled microchannel structure with dimensional parameters is pre-designed, the size of the raw material plate 1 is determined according to the length, width and thickness of the model, and grooves with the same number as the microchannels are processed on the raw material plate 1, and the width of the groove is equal to the distance between the midpoints of the two side walls of the designed microchannel as the curvature changes.

[0029] The groove has an arc-shaped raised groove bottom 3, which has a greater thickness than the flat groove bottom. When pressed with a certain curvature, the arc-shaped raised groove bottom 3 with increased thickness is stretched to compensate for the bottom wall thickness of the microchannel in the variable curvature thin-walled microchannel structure.

[0030] The microchannel of the variable curvature thin-walled microchannel structure changes from a rectangular shape to a fan shape when it is a flat plate part, and the arc length of the inner side is smaller than the arc length of the outer side. The curvature of the microchannel bottom at different positions of the variable curvature thin-walled microchannel structure is different, and the arc length is also different. The arc length of the arc-shaped raised groove bottom 3 is positively correlated with the arc length of the designed microchannel outer side of the variable curvature thin-walled microchannel structure to ensure that the wall thickness of the bottom of all microchannels is consistent after profiling. In the embodiment of the present invention, if Figure 3 , 4As shown, the arc length of the arc-shaped raised groove bottom 3 of the groove is equal to the arc length of the outer side of the microchannel of the variable curvature thin-wall microchannel structure designed at the corresponding position.

[0031] The number of arc-shaped protrusions on the arc-shaped protrusion groove bottom 3 can be one, two or more, so as to be suitable for the case where the curvature of the variable curvature thin-walled microchannel structure is large. The number of arc-shaped protrusions on the arc-shaped protrusion groove bottom 3 is positively correlated with the curvature of the profile outside the microchannel of the designed variable curvature thin-walled microchannel structure. Figure 6 As shown, when the number of arc-shaped protrusions is two, adjacent arc-shaped protrusions have a smooth transition in an arc shape, thereby avoiding cracks between the two arc-shaped protrusions during the mold pressing process.

[0032] S2: diffusion welding a cover plate 4 on the front side of the bottom plate 2 to cover the bottom plate 2 to obtain a first prefabricated plate 5.

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

[0034] S3: Processing the back side of the first prefabricated plate 5 so that the bottom of the channel has a groove 6 with the same shape as the arc-shaped raised groove bottom 3, thereby obtaining a second prefabricated plate 7.

[0035] A portion of the back side of the first prefabricated plate 5 is removed to form a groove 6 at the bottom of the channel, and the shape of the groove 6 is the same as that of the arc-shaped raised groove bottom 3, and the groove 6 corresponds to the outer side of the strain curvature thin-wall microchannel structure. During mold pressing, the arc-shaped raised groove bottom 3 and the groove 6 are stretched outward and extended to both sides, and finally a smooth arc-shaped structure is formed.

[0036] In the embodiment of the present invention, due to the increase of wall thickness, the elongation rate will be inconsistent during the pressing process. The position with large wall thickness has high strength, and the position with small wall thickness has low strength. Therefore, in order to avoid cracking at the position with small wall thickness during the pressing process and further ensure the consistency of the wall thickness at the bottom of the microchannel, as shown in FIG. Figure 5 , 6 As shown, the back side of the second prefabricated plate 7 is processed so that the wall thickness of the arc-shaped raised groove bottom 3 on the second prefabricated plate 7 is equal at each location, and the thickness of the arc-shaped raised groove bottom 3 is much smaller than the width of the ribs between each groove.

[0037] S4: using the mold 8 to press-form the second prefabricated plate 7 to obtain a variable curvature thin-wall microchannel structure.

[0038] The following is a detailed description through specific embodiments.

[0039] Example 1

[0040] The embodiment of the present invention provides a manufacturing process of a variable curvature thin-wall microchannel structure, comprising the following steps:

[0041] 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 of 100mm and a width of 50mm. 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.

[0042] The thickness of the raw material plate is 3mm. A groove with a width of 2mm and a maximum depth of 1mm is processed on the raw material plate. 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. The bottom plate is obtained. The groove has an arc-shaped convex groove bottom, such as Figure 3 , 4 As shown, the arc surface lengths l1, l2, l3, l4, l5, l6, l7, l8, l9, l10, l11, l12 of the arc-shaped raised groove bottom of each groove are respectively equal to the arc lengths L1, L2, L3, L4, L5, L6, L7, L8, L9, L10, L11, L12 of the outer side of the microchannel of the designed variable curvature thin-walled microchannel structure, and the arc-shaped raised groove bottom is an arc-shaped raised structure.

[0043] 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.

[0044] The bottom plate and the cover plate are then subjected to surface nickel plating, rinsed with tap water, cleaned with deionized water and rinsed multiple times, and dried for later use.

[0045] Before diffusion welding of the base plate and the cover plate, the surface of each welding tool is coated with solder resist and dried for use.

[0046] 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 is performed using the diffusion welding parameters shown to obtain a first prefabricated plate.

[0047] The first prefabricated board is taken out of the oven after being cooled, and a groove is processed on the back side of the first prefabricated board at the position corresponding to the groove. The shape of the groove is the same as the shape of the bottom of the arc-shaped raised groove in the groove, so that the wall thickness of the bottom of the groove is consistent, both are 1mm, to obtain the second prefabricated board.

[0048] The second prefabricated plate is heated to 900° C. in a heating furnace with protective gas, kept warm for 1 hour, and then placed in a variable curvature profile pressing mold for pressing to obtain a variable curvature thin-wall microchannel structure.

[0049] 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 manufacturing process for a variable curvature thin-walled microchannel structure, characterized in that: The following steps are involved: A groove is processed on the front side of the raw material plate according to the number of microchannels of the designed variable curvature thin-wall microchannel structure to obtain a bottom plate, wherein the groove has an arc-shaped convex groove bottom; Diffusion welding a cover plate on the front side of the bottom plate to cover the bottom plate, so as to obtain a first prefabricated plate; Processing the back side of the first prefabricated plate so that the bottom of the channel has a groove having the same shape as the bottom of the arc-shaped raised groove, thereby obtaining a second prefabricated plate; Using a mold to press-form the second prefabricated plate to obtain a variable curvature thin-wall microchannel structure; The arc length of the arc-shaped raised groove bottom of the groove is equal to the arc length of the outer side of the microchannel of the variable curvature thin-wall microchannel structure designed at the corresponding position.

2. The manufacturing process of the variable curvature thin-wall microchannel structure according to claim 1, characterized in that: The arc length of the arc-shaped raised groove bottom is positively correlated with the arc length of the outer side of the microchannel of the designed variable curvature thin-wall microchannel structure.

3. The manufacturing process of the variable curvature thin-wall microchannel structure according to claim 1, characterized in that: The number of the arc-shaped protrusions at the bottom of the arc-shaped protrusion groove is positively correlated with the curvature of the profile of the outer side of the microchannel of the designed variable curvature thin-wall microchannel structure.

4. The manufacturing process of the variable curvature thin-wall microchannel structure according to claim 3, characterized in that: Adjacent arc-shaped protrusions transition smoothly in an arc shape.

5. The manufacturing process of the variable curvature thin-wall microchannel structure according to claim 1, characterized in that: The wall thickness of each part of the bottom of the arc-shaped raised groove on the second prefabricated plate is equal.

6. The manufacturing process of the variable curvature thin-wall microchannel structure according to claim 1, characterized in that: The width of the channel is equal to the distance between the midpoints of the two side walls of the designed microchannel as the curvature changes.

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