Forming method and die for reducing edge damage of elongated curved-surface flanging part

Abstract

The invention provides a forming method for reducing edge damage of an extension type curved-surface flanged part, which comprises the steps of bending deformation and flanging deformation, and aims to provide the forming method for reducing edge damage of the extension type curved-surface flanged part, and guide a material in a non-extension deformation area to preferentially generate flanging deformation through an innovative die design, so that the production efficiency of the extension type curved-surface flanged part is improved. According to the method and the mold, tangential pressure stress is overlaid on the two sides of an elongation deformation area to improve the local stress state and induce instability to promote material aggregation in the area, so that the damage risk is remarkably reduced, the cracking phenomenon is effectively restrained, and high-quality and high-reliability forming manufacturing is achieved. The damage value of an elongation deformation area is reduced to 0.231, and the damage reduction amplitude reaches 41.9%.

Description

Technical Field

[0001] The invention relates to the technical field of edge bending processing of belt conveyor body parts, in particular to an edge bending process for belt conveyor body parts. Background Art

[0002] The present invention mainly addresses the problem of cracking at the edges of belt conveyor body parts during bending, develops a new process for forming edge-crack-free support parts, and develops corresponding new molds to effectively reduce the edge cracking rate; to address the problems of multiple molds and low production efficiency caused by parts with multiple specifications, a flexible composite mold is developed, and key module design criteria for different material properties, cutting methods and bending angles are developed to achieve mold sharing for edge support parts of multiple specifications, reduce mold redundancy, and improve production efficiency.

[0003] Flanging is an important processing method in stamping production. According to the shape of the bottom surface of the flanging blank, the flanging process can be divided into flat flanging and curved flanging: when flanging is performed on a flat blank or the flat area of ​​a blank, it is called flat flanging; when flanging is performed on a curved blank or the curved area of ​​a blank, it is called curved flanging; according to the deformation characteristics, the flanging process can be divided into elongation flanging and compression flanging: the maximum principal stress of the elongation flanging is manifested as a tensile stress acting in the tangential direction, and the macroscopic manifestation is an elongation deformation in this direction; the maximum principal stress of the compression flanging is manifested as a compressive stress acting in the tangential direction, and the macroscopic manifestation is a compression deformation in this direction. During the elongation curved flanging process, under the action of the tangential tensile stress, the boundary of the deformation zone is easily affected by stress concentration, thereby increasing the risk of cracking.

[0004] At present, there are two main methods for the forming process of elongated curved surface flanging parts: one is bending-flanging forming, that is, first using a forming mold to form the curved surface, and then flanging processing, such as Figure 1 As shown; the other is flanging-bending forming, that is, first flanging the plane, and then through the forming process to make it reach the desired curved surface shape as shown Figure 2 However, both methods fail to solve the problem of cracking caused by tensile stress at the boundary of the elongation deformation zone.

[0005] Patent CN201110373157.5 reports a forming method for 90° web reverse flanging. This method bends the sheet material to 90° while simultaneously pressing the edges of the bent portion into a wavy shape, allocating material for the subsequent flanging process and, to a certain extent, reducing edge damage to the formed part. However, this method requires the use of two sets of molds for step-by-step forming, increasing the complexity and time cost of the production process. Furthermore, the wavy design is somewhat difficult. If not designed properly, it may lead to uneven material flow during flanging, affecting the forming quality. Furthermore, the wavy line forming process inevitably applies deformation forces to the sheet material, which is already subject to significant stress and deformation, greatly increasing the risk of cracking after forming. Summary of the Invention

[0006] In view of the above defects, the present invention proposes a forming method for reducing edge damage of elongated curved surface flanging parts, comprising the following steps: Bending deformation: bending the sheet metal into a curved surface with a preset curvature; Flanging deformation: The upper and lower molds are used to bend the sheet metal that already has a curvature to form a flanging. The bending process is to first form a non-elongation deformation zone, then form an elongation deformation zone, and at the same time superimpose tangential compressive stress on the elongation deformation zone, and it is a continuous action.

[0007] Preferably, the method further includes the following steps: the flanging deformation first forms a non-elongation deformation zone and then forms an elongation deformation zone, which is achieved by controlling the speed at which the upper mold moves downward.

[0008] Preferably, the method further comprises the following steps: the continuous action of flanging deformation is achieved by controlling the speed at which the upper mold moves downward.

[0009] The purpose of the present invention is to provide a forming method for reducing edge damage of elongated curved flanged parts, and through innovative mold design, guide the material in the non-elongation deformation zone to undergo flange deformation first, and superimpose tangential compressive stress on both sides of the elongation deformation zone to improve the local stress state and induce instability to promote material aggregation in this area, thereby significantly reducing the risk of damage and effectively inhibiting cracking, and achieving high-quality and high-reliability forming and manufacturing.

[0010] Compared with the traditional method, the method and mold of the present invention reduce the damage value of the elongation deformation zone to 0.231, and the damage reduction rate reaches 41.9%. Figure 10 . BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a schematic diagram of a bending-flanging forming method in the prior art.

[0012] Figure 2 It is a schematic diagram of another bending-flanging forming method in the prior art.

[0013] Figure 3 This is a schematic diagram of a conventional flanging deformation forming method in the prior art. It shows that the position of the elongated deformation zone remains unchanged, and the force applied to it remains unchanged.

[0014] Figure 4 This is a schematic diagram of the flange deformation forming method of the present invention, in which it is shown that the position of the elongated deformation zone gradually moves from both sides to the center, and does not remain unchanged.

[0015] Figure 5 for Figure 3 Another angle diagram.

[0016] Figure 6 for Figure 4 Another angle diagram.

[0017] Figure 7 Schematic diagram of the mold of the present invention.

[0018] Figure 8 Schematic diagram of the die.

[0019] Figure 9 This is a schematic diagram of the die from another angle.

[0020] Figure 10 This is an analysis and detection diagram of the sheet material obtained by the method and mold processing of the present invention.

[0021] In the figure: the die 10, the shaping surface 11, the blade surface 12, the inner concave shape 121, the outer convex area 122, and the punch 20. DETAILED DESCRIPTION

[0022] See also Figure 3-6 The present invention proposes a forming method for reducing edge damage of elongated curved surface flanging parts, comprising the following steps: Bending deformation: bending the sheet metal into a curved surface with a preset curvature; Flanging deformation: The upper and lower molds are used to bend the sheet metal that already has a curvature to form a flanging. The bending process is to first form a non-elongation deformation zone, then form an elongation deformation zone, and at the same time superimpose tangential compressive stress on the elongation deformation zone, and it is a continuous action.

[0023] Furthermore, the method further comprises the following steps: the flanging deformation first forms a non-elongation deformation zone and then forms an elongation deformation zone, which is achieved by controlling the speed at which the upper die moves downward.

[0024] Furthermore, the method further comprises the following steps: the continuous action of flanging deformation is achieved by controlling the speed at which the upper mold moves downward.

[0025] The continuous action of the flanging deformation is to reduce the damage to the edges of the elongated curved surface flanging parts by delaying the flanging time of the elongation deformation zone and superimposing the tangential compressive stress. The delaying of the flanging time of the elongation deformation zone is to adjust the contact sequence between the flanging blade and the sheet material during the flanging deformation, and preferentially guide the non-elongation deformation zone material to undergo flanging deformation, so as to avoid the elongation deformation zone material from entering the flanging stage too early, and store enough material for the elongation deformation zone before flanging. The superimposed tangential compressive stress is to superimpose the tangential compressive stress toward the center of the elongation deformation zone on both sides of the elongation deformation zone during the flanging deformation to adjust the tangential stress state there and induce local instability, thereby prompting the material to gather in this area, and alleviating the damage and rupture of the edge of this area due to excessive tangential tensile stress. Figure 4 、6 The position of the elongation deformation zone in the figure moves. Figure 3 、 5 ,In the traditional design method, the position of the elongation deformation zone remains unchanged during ,the flanging deformation.

[0026] See also Figure 7-9 The present invention also proposes a forming die for reducing edge damage of elongated curved surface flanging parts, comprising an upper and lower matching die 10 and punch 20, wherein the lower edge of the die 10 and the upper edge of the punch 20 both have flanging blades. The die is designed to have a flanging blade shape to achieve the above-mentioned method of delaying the flanging time of the elongation deformation zone and superimposing the tangential compressive stress during the flanging process, thereby achieving the purpose of reducing edge damage of elongated curved surface flanging parts. The die 10 includes a shaping surface 11 and a blade surface 12. The shaping surface 11 is used to cooperate with the punch 20 in the final stage of flanging forming to make the part reach the required shape, size and precision; the blade surface 12 is a beveled shape that gradually compensates from both ends to the center position, and is used to contact the flanging part of the sheet during flanging forming and apply force to the sheet to cause flanging deformation. Due to the beveled shape of the blade with shorter ends and longer middle, when moving downward, the force applied to the sheet is also gradually applied from both sides to the center; the die blade surface 12 includes an inner concave shape 121 and an outer convex area 122, and the inner concave shape 121 and the outer convex area 122 are W-shaped.

[0027] The die's blade surface 12 forms a concave shape 121 in the elongated deformation zone of the elongated curved flange. This serves to delay contact between the flange's blade surface and the material in the elongated deformation zone, guiding the material in the non-elongated deformation zone to deform preferentially, thereby storing sufficient material in the elongated deformation zone before flanging. Simultaneously, two convex regions 122 are formed at the junction of the concave blade surface 12 and the non-concave blade surface. These convex regions 122 form a protrusion, which forms a W-shape with the concave shape 121. These two protrusions exert force on the sheet during flanging, restricting the lateral flow of material in the elongated deformation zone. As flanging continues, the die moves downward, and the elongated deformation zone gradually decreases. The presence of the two protrusions not only restricts the lateral flow of material, but also applies a tangential compressive stress toward the center of the material, inducing local instability and causing the material to aggregate toward the center of the region, effectively alleviating edge damage and cracking caused by excessive tangential tensile stress.

[0028] The bending deformation in the present invention is achieved by using conventional molds in the prior art, while this solution uses a professional mold for flanging deformation.

[0029] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of this patent.

Claims

1. A forming method for reducing edge damage of elongated curved surface flanged parts, characterized in that The following steps are involved: Bending deformation: bending the sheet metal into a curved surface with a preset curvature; Flanging deformation: The upper and lower molds are used to bend the sheet metal that already has a curvature to form a flanging. The bending process is to first form a non-elongation deformation zone, then form an elongation deformation zone, and at the same time superimpose tangential compressive stress on the elongation deformation zone, and it is a continuous action.

2. The forming method for reducing edge damage of elongated curved surface flanged parts according to claim 1, characterized in that The following steps are involved: The flanging deformation first forms the non-elongation deformation zone and then forms the elongation deformation zone, which is achieved by controlling the speed at which the upper die moves downward.

3. The forming method for reducing edge damage of elongated curved surface flanged parts according to claim 1, characterized in that The following steps are involved: The continuous action of flanging deformation is achieved by controlling the speed at which the upper die moves downward.

4. A forming die for reducing edge damage of elongated curved surface flanged parts, characterized in that It includes upper and lower matching concave and convex dies, the lower edge of the concave die and the upper edge of the convex die both have flanging cutting edges, the concave die includes a shaping surface and a cutting edge surface, the shaping surface is used to cooperate with the punch in the final stage of flanging forming; the cutting edge surface is a beveled shape that gradually compensates from both ends to the center position, and is used to contact the flanging part of the sheet metal during flanging forming, and exert force on the sheet metal to cause flanging deformation. Due to the beveled shape of the cutting edge with shorter ends and longer middle, when moving downward, the force applied to the sheet metal is also gradually applied from both sides to the center; the cutting edge surface of the die includes an inner concave shape and an outer convex area, and the inner concave shape and the outer convex area are W-shaped.

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