A method for forming a concave thin sheet stainless steel part

Abstract

The application discloses a forming method for concave thin plate corrugated stainless steel parts, which comprises die assembling, stamping buffer layer laying, stamping preforming, stamping forming and shearing correction. By using the forming method, the existing punch is used, in the stamping preforming process, the stamping buffer layer is laid, the step-by-step pressing mode is adopted, the stamping buffer layer can control the material flow problem, so that the material uniformity is achieved; in the stamping forming, the die is replaced, and the one-time pressing forming is adopted, which can effectively solve the technical problem that the boundary of the corrugated area is prone to wrinkling, and can improve the forming efficiency, so as to improve the qualified rate of part forming, ensure the product forming quality, greatly reduce the processing cost, and be applied to the processing of the parts prone to wrinkling, and is convenient to operate and suitable for popularization and application.

Description

Technical Field

[0001] This invention relates to the field of sheet metal forming technology, specifically to a forming method for concave thin sheet corrugated stainless steel parts. Background Technology

[0002] In sheet metal forming, besides structurally regular parts, irregularly shaped parts are frequently encountered, such as concave thin-plate corrugated stainless steel parts with a thickness of only 0.5mm. These parts exhibit a certain curvature and are irregularly shaped, with numerous densely arranged reinforcing ribs designed on their surface to meet strength requirements. When using existing stamping processes for these parts, the dense internal reinforcing ribs and thin material cause the material in the reinforcing rib area to shrink drastically towards the center during stamping, while excessive material flow occurs outside the rib area. This leads to tangential strain at the junction of the rib area and the edges of the part, and wrinkling along the edges of the ribs, resulting in decreased part quality and even product scrap. Therefore, to meet the processing requirements of these parts, existing stamping methods need to be improved. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the problems existing in the background art by providing a convenient forming method. This forming method utilizes an existing punch press and adds a buffer layer to the existing mold, and adopts a multiple stamping process to avoid the shrinkage of the material in the reinforcing rib area that causes wrinkling, thereby improving processing efficiency and product quality, and reducing processing costs. Specifically, it is a forming method for concave thin plate corrugated stainless steel parts.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a forming method for concave thin plate corrugated stainless steel parts, the forming method including mold mounting, laying a stamping buffer layer, stamping pre-forming, stamping forming and shearing correction, specifically including the following steps:

[0005] (1) Mold installation: First, install the pre-forming mold on the punch press worktable. The upper mold of the pre-forming mold is a punch made of lead alloy, while the lower mold is a die made of zinc alloy. Then, place the stainless steel blank to be formed in the lower mold after the mold is opened. Finally, adjust the clearance of the punch press worktable according to the thickness of the stainless steel blank to be formed and the thickness of the multi-layer rubber to increase the closing gap between the upper and lower molds in the pre-forming mold.

[0006] (2) Lay out the stamping buffer layer. According to the thickness of the stainless steel blank to be formed, first lay multiple layers of hard rubber pads from bottom to top on the stainless steel blank in the lower mold, and then lay a soft rubber pad on the top layer of rubber pads. Use the laid hard rubber pads and soft rubber pads to stamp the buffer layer.

[0007] (3) Stamping preforming: Under the action of the punch press, the stainless steel blank is stamped and preformed multiple times using a preforming mold, with an upper mold made of lead alloy and a lower mold made of zinc alloy to obtain a semi-finished product.

[0008] (4) Stamping: Before the stamping process, the pre-forming mold installed on the press workbench is replaced with the inspection and correction mold. The upper mold made of epoxy resin is replaced with the lead alloy upper mold in the pre-forming mold, and the lower mold made of cast steel is replaced with the zinc alloy lower mold in the pre-forming mold. Then the closing gap between the upper and lower molds in the inspection and correction mold is adjusted so that when the upper and lower molds in the inspection and correction mold are closed during the stamping process, the upper and lower molds can be completely fitted without any closing gap. Finally, under the action of the press, the upper mold made of epoxy resin and the lower mold made of cast steel are used to stamp the semi-finished product to obtain the stamped finished product.

[0009] (5) Shearing and correction: The stamped product obtained after stamping is sheared according to the design requirements, and the part is locally corrected and shaped to obtain the finished part.

[0010] Furthermore, in the forming method for concave thin-plate corrugated stainless steel parts described in this invention, during the mold mounting process in step (1), the punch press worktable includes an upper worktable and a lower worktable. The upper mold of the preforming mold is installed under the upper worktable, while its lower mold is installed on the lower worktable. The specific way to adjust the gap of the punch press worktable is to adjust the upper worktable upward by 40mm according to the thickness of the stainless steel blank to be formed and the thickness of the multi-layer rubber. By adjusting the upper worktable in the punch press worktable upward, the gap between the upper mold and the lower mold in the preforming mold is increased.

[0011] Furthermore, in the forming method for concave thin plate corrugated stainless steel parts described in this invention, during the process of laying the stamping buffer layer in step (2), the hard rubber pad is made of polyurethane rubber with a thickness of 10mm, and the number of layers is four, while the soft rubber pad is made of soft rubber skin with a thickness of 5mm.

[0012] Furthermore, in the forming method for concave thin-plate corrugated stainless steel parts described in this invention, during the stamping pre-forming process in step (3), under the action of the punch press, the stainless steel blank is first pre-formed by using an upper die made of lead alloy and a lower die made of zinc alloy. Then, a layer of hard rubber pad is removed from the lower die. At the same time, the upper worktable in the punch press needs to be finely adjusted so that the downward adjustment distance of the upper worktable is consistent with the thickness of the hard rubber pad. After the adjustment is completed, the second stamping pre-forming is performed, and so on. After multiple stamping pre-formings, until there is still a layer of hard rubber pad and a soft rubber pad in the lower die. During this process, the distance of the upper worktable adjusted downwards should be less than the thickness of the hard rubber pad. After adjustment, pre-forming is performed. After pre-forming, the last layer of hard rubber pad in the lower die is removed. The upper worktable in the press is then finely adjusted again so that the downward adjustment distance of the upper worktable is consistent with the thickness of the hard rubber pad, and its gap is controlled to be the same as that of the soft rubber pad. Pre-forming is then performed again. After pre-forming, the soft rubber pad is removed from the lower die. The upper worktable in the press is then finely adjusted so that the downward adjustment distance of the upper worktable is less than the thickness of the soft rubber pad. Finally, pre-forming is performed again to obtain the semi-finished product.

[0013] Furthermore, in the forming method for concave thin plate corrugated stainless steel parts described in this invention, during the stamping process in step (4), the lower die of the inspection and correction mold is equipped with reinforcing ribs that match the stainless steel parts. Under the action of the punch press, the upper die made of epoxy resin and the lower die made of cast steel are used to stamp the semi-finished product to obtain a stamped finished product with reinforcing ribs.

[0014] Furthermore, in the forming method for concave thin-plate corrugated stainless steel parts described in this invention, the punch press is a 400-630 ton hydraulic punch press.

[0015] The forming method for concave thin-plate corrugated stainless steel parts described in this invention has the following advantages compared with existing technologies: Using existing punch presses, during the pre-forming process, a step-by-step pressing method is adopted through the laid-out stamping buffer layer. Utilizing the property of polyurethane rubber to generate a reaction force after compression under external force, pressure can be applied to the material surface, thus controlling the problem of violent material flow and achieving uniform material collection. In the stamping process, by replacing the mold with one containing reinforcing ribs for inspection and correction, a stamped product with reinforcing ribs can be obtained in a single pressing operation. This effectively avoids tangential strain at the junctions between the reinforcing rib areas and the surrounding edges, thus preventing wrinkling. Furthermore, the forming method described in this invention, compared with existing forming methods, basically eliminates the need for manual correction. Existing forming methods generally require manual correction, which takes about 40 minutes to complete for a single part. The improved forming method almost eliminates the need for manual correction. Even if there are occasional minor flaws, they are only minor local corrections, without the need for large-area manual correction. This not only greatly improves forming efficiency but also reduces labor costs.

[0016] Therefore, the forming method described in this invention can not only effectively solve the technical problem of wrinkling at the boundary of the corrugated area, but also improve its forming efficiency, thereby increasing the pass rate of part forming, ensuring product forming quality, and greatly reducing processing costs. It can be applied to the processing of easily wrinkled parts, and its operation is convenient and suitable for widespread application. Attached Figure Description

[0017] The present invention will now be described in further detail with reference to the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of the lower mold structure in an existing preforming mold;

[0019] Figure 2 for Figure 1 A schematic diagram of the structure after the middle and lower dies have been laid with the stamping buffer layer;

[0020] Figure 3 This is a schematic diagram of the lower mold structure in an existing inspection and calibration mold.

[0021] Figure 4 Product parts obtained using the method described in this invention Figure 1 ;

[0022] Figure 5 Product parts obtained using the method described in this invention Figure 2 ;

[0023] Figure 6 The product part drawing obtained using existing methods;

[0024] Figure 7 This is a physical image of the lower mold in an existing preforming mold.

[0025] Figure 8 This is a photograph of the existing inspection and calibration mold assembly.

[0026] Figure 9 This is a photograph of the existing inspection and calibration mold when it is opened. Detailed Implementation

[0027] To further illustrate the concept of the present invention, specific embodiments are described below to illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0028] It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness or purpose of the invention, should still fall within the scope of the technical content disclosed herein. Furthermore, terms such as "above," "below," "front," and "back" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection" and "provided with" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] It should be noted that the term "comprising" or any other variation is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0031] like Figures 1 to 3 As shown, this embodiment provides a forming method for a concave corrugated stainless steel part with a thickness of 0.5 mm. The forming method includes mold mounting, laying a stamping buffer layer, stamping pre-forming, stamping forming, and shearing correction, specifically including the following steps:

[0032] (1) Mold installation: The existing 630-ton hydraulic punch press is used as the power source. The punch press worktable includes an upper worktable and a lower worktable. First, a pre-forming mold is installed on the punch press worktable. The upper mold of the pre-forming mold is a punch made of lead alloy, while the lower mold is a die made of zinc alloy. The upper mold is installed on the upper worktable, and the lower mold is installed on the lower worktable. Then, the stainless steel blank to be formed is placed in the lower mold after the mold is opened. Finally, the gap of the punch press worktable is adjusted according to the thickness of the stainless steel blank to be formed and the thickness of the multi-layer rubber. The upper worktable is adjusted upward by 40mm. By adjusting the upper worktable of the punch press worktable upward, the closing gap between the upper and lower molds in the pre-forming mold is increased.

[0033] (2) Laying the stamping buffer layer: According to the thickness of the stainless steel blank to be formed, first lay four layers of hard rubber pads from bottom to top on the stainless steel blank in the lower mold, and then lay a soft rubber pad on the top layer of rubber pads. Use the laid hard rubber pads and soft rubber pads to form the stamping buffer layer; wherein, the hard rubber pad is made of polyurethane rubber with a thickness of 10mm, and the soft rubber pad is made of soft rubber skin with a thickness of 5mm.

[0034] (3) Stamping preforming: Under the action of the punch press, the stainless steel blank is stamped and preformed multiple times using a preforming die made of lead alloy upper die and zinc alloy lower die to obtain a semi-finished product. The specific operation method is as follows: Since the thickness of each layer of hard rubber pad is 10mm, and a soft rubber pad is placed on the fourth layer of hard rubber pad, the function of the soft rubber pad is to strengthen the buffering effect when the die is closed and pressed, and to prevent the punch press from overload and stalling. Under the action of the punch press, the stainless steel blank is first stamped and preformed using a lead alloy upper die and a zinc alloy lower die. After each pressing, a layer of hard rubber pad needs to be removed from the lower die. At the same time, the upper worktable in the punch press worktable needs to be finely adjusted, and the upper worktable is adjusted downward by 10mm. This distance is the same as the thickness of the hard rubber pad. The operation method for the first three times is the same. The same applies, but the order of removing the hard rubber pads is from top to bottom: the third layer, the second layer, the fourth layer, until only the last hard rubber pad and the soft rubber pad remain. At this point, the distance of the upper worktable in the punch press is different from the previous three times. Simply adjust the upper worktable downwards by 8mm. After punching, remove the last layer (i.e., the first layer) of hard rubber pad. At this point, the distance of the upper worktable in the punch press is the same as the previous three times. That is, adjust the upper worktable downwards by 10mm, leaving the last soft rubber pad. After punching, remove the soft rubber pad. Fine-tune the distance of the upper worktable in the punch press by adjusting the upper worktable downwards by 2mm. Finally, without the effect of the punching buffer layer, use a lead alloy upper die and a zinc alloy lower die to punch the stainless steel blank. Press it for the last time to obtain the semi-finished product.

[0035] (4) Stamping: Before the stamping process, the pre-forming mold installed on the press workbench is replaced with the inspection and correction mold. The upper mold made of epoxy resin is replaced with the lead alloy upper mold in the pre-forming mold, and the lower mold made of cast steel is replaced with the zinc alloy lower mold in the pre-forming mold. The lower mold in the inspection and correction mold is equipped with reinforcing ribs that match the stainless steel parts. Then, the closing gap between the upper and lower molds in the inspection and correction mold is adjusted so that when the upper and lower molds in the inspection and correction mold are closed during the stamping process, the upper and lower molds can be completely fitted without any closing gap. Finally, under the action of the press, the upper mold made of epoxy resin and the lower mold made of cast steel are used to stamp the semi-finished product to obtain the stamped finished product with reinforcing ribs.

[0036] (5) Shearing and straightening: The stamped product obtained after stamping is sheared according to the design requirements, and the part is locally straightened and shaped to obtain the finished part, such as... Figure 4 and Figure 5 The image shown is of a part obtained using the method described in this invention. Figure 6 For parts obtained using existing methods, all molds used are existing molds, such as... Figures 7 to 9 As shown in the image, a comparison reveals that existing methods are prone to wrinkling.

[0037] Using the forming method described in this invention, during the stamping pre-forming process, multiple layers of hard rubber pads and one layer of soft rubber pads are laid on the stainless steel blank in the lower die. The hard rubber pads are made of polyurethane rubber with a thickness of 10mm, while the soft rubber pads are made of soft rubber skin with a thickness of 5mm. A step-by-step pressing method is adopted, and one layer of hard rubber pads is removed after each pressing. Utilizing the property of polyurethane rubber to generate a reaction force after compression under external force, pressure can be applied to the material surface, which can control the problem of violent material flow and achieve the purpose of uniform material collection. In the stamping forming, by replacing the inspection and correction die with reinforcing ribs, a stamped product with reinforcing ribs can be obtained in one pressing. This can effectively avoid tangential strain at the junction of the reinforcing rib area and the surrounding edges, thus preventing wrinkling problems.

[0038] In summary, the forming method described in this invention utilizes an existing punch press and, during the stamping process, lays a stamping buffer layer in the existing mold and adopts a multiple stamping method. By leveraging the elasticity of rubber, the flow of material during the forming process can be effectively controlled, ensuring uniform flow of the material under forming force. This achieves the goal of preventing wrinkles in the parts. It not only effectively solves the technical problem of wrinkles easily forming at the boundaries of the corrugated area but also improves forming efficiency, thereby increasing the pass rate of part forming, ensuring product forming quality, and significantly reducing processing costs. It can be applied to the processing of easily wrinkled parts, is easy to operate, and is suitable for widespread application.

[0039] Other aspects of this invention that are not detailed herein are all conventional techniques known to those skilled in the art.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A forming method for concave thin-plate corrugated stainless steel parts, characterized in that: The forming method includes mold mounting, laying a stamping buffer layer, stamping pre-forming, stamping forming, and shearing correction, specifically including the following steps: (1) Mold installation: First, install the pre-forming mold on the punch press workbench. The upper mold of the pre-forming mold is a punch, and the lower mold is a die. Then, place the stainless steel blank to be formed in the lower mold after the mold is opened. Finally, adjust the clearance of the punch press workbench according to the thickness of the stainless steel blank to be formed and the thickness of the multi-layer rubber pads, so as to increase the closing clearance between the upper and lower molds in the pre-forming mold. (2) Lay out the stamping buffer layer. According to the thickness of the stainless steel blank to be formed, first lay multiple layers of hard rubber pads from bottom to top on the stainless steel blank in the lower mold, and then lay a soft rubber pad on the top layer of rubber pads. Use the laid hard rubber pads and soft rubber pads as the stamping buffer layer. (3) Stamping preforming: Under the action of the punch press, the stainless steel blank is stamped and preformed multiple times using a preforming mold, with an upper mold made of lead alloy and a lower mold made of zinc alloy to obtain a semi-finished product. In the aforementioned stamping preforming process, under the action of the punch press, the stainless steel blank is first preformed using an upper die made of lead alloy and a lower die made of zinc alloy. Then, a layer of hard rubber pad is removed from the lower die. Simultaneously, the upper worktable in the punch press needs to be finely adjusted so that the downward adjustment distance of the upper worktable matches the thickness of the hard rubber pad. After adjustment, a second stamping preforming is performed, and so on. After multiple stamping preforming processes, until there is still a layer of hard rubber pad and a soft rubber pad in the lower die, the downward fine adjustment distance of the upper worktable should be less than [a certain value]. After adjusting the thickness of the hard rubber pad, it is pre-formed by stamping. After pre-forming by stamping, the last layer of hard rubber pad in the lower die is removed. The upper worktable in the stamping machine is then finely adjusted so that the downward adjustment distance of the upper worktable is consistent with the thickness of the hard rubber pad, and its gap is controlled to be the same as that of the soft rubber pad. Then, it is pre-formed by stamping again. After pre-forming by stamping, the soft rubber pad is removed from the lower die. Then, the upper worktable in the stamping machine is finely adjusted so that the downward adjustment distance of the upper worktable is less than the thickness of the soft rubber pad. Finally, it is pre-formed by stamping again to obtain the semi-finished product. (4) Stamping: Before the stamping process, the pre-forming mold installed on the press workbench is replaced with the inspection and correction mold. The upper mold made of epoxy resin is replaced with the lead alloy upper mold in the pre-forming mold, and the lower mold made of cast steel is replaced with the zinc alloy lower mold in the pre-forming mold. Then the closing gap between the upper and lower molds in the inspection and correction mold is adjusted so that when the upper and lower molds in the inspection and correction mold are closed during the stamping process, the upper and lower molds can be completely fitted without any closing gap. Finally, under the action of the press, the upper mold made of epoxy resin and the lower mold made of cast steel are used to stamp the semi-finished product to obtain the stamped finished product. (5) Shearing and correction: The stamped product obtained after stamping is sheared according to the design requirements, and the part is locally corrected and shaped to obtain the finished part.

2. The forming method for a concave thin-plate corrugated stainless steel part according to claim 1, characterized in that: In the mold assembly process of step (1), the punch press worktable includes an upper worktable and a lower worktable. The upper mold of the preforming mold is installed under the upper worktable, and its lower mold is installed on the lower worktable. The specific way to adjust the gap of the punch press worktable is to adjust the upper worktable upward by 40mm according to the thickness of the stainless steel blank to be formed and the thickness of the multi-layer rubber. By adjusting the upper worktable in the punch press worktable upward, the gap between the upper mold and the lower mold in the preforming mold is increased.

3. The forming method for concave thin-plate corrugated stainless steel parts according to claim 1, characterized in that: In the process of laying the stamping buffer layer in step (2), the hard rubber pad is made of polyurethane rubber with a thickness of 10mm and is laid in four layers, while the soft rubber pad is made of soft rubber skin with a thickness of 5mm.

4. The forming method for concave thin-plate corrugated stainless steel parts according to claim 1, characterized in that: In the stamping process of step (4), the lower die of the inspection and correction mold is equipped with reinforcing ribs that match the stainless steel parts. Under the action of the punch press, the upper die made of epoxy resin and the lower die made of cast steel are used to stamp the semi-finished product to obtain the stamped finished product with reinforcing ribs.

5. The forming method for a concave thin-plate corrugated stainless steel part according to claim 1, characterized in that: The punch press is a 400-630 ton hydraulic punch press.

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