A process for incremental forming

Abstract

The application relates to a kind of progressive forming process methods, comprising the following steps: S1, each clamping unit is adjusted to uniform vertical height, and the rotation angle of lower clamping head and upper clamping head is adjusted to set reference posture, and the clamping surface is relatively flat;S2, metal sheet is placed and clamped and fixed between the lower clamping head and the upper clamping head of each clamping unit;S3, according to the three-dimensional surface topography of target workpiece, the height and clamping head angle of each clamping unit are gradually adjusted, and the metal sheet is preliminarily fitted to the target topography;S4, the position and posture of all clamping units are locked, and a stable curved surface support structure is constructed;S5, the sheet is progressively formed using a progressive forming tool head;S6, after forming, the clamping force is released and the workpiece is removed.Compared with the prior art, the application has the advantages of improving forming quality and material utilization, improving processing efficiency and trajectory accuracy, high flexibility and versatility, reducing production cost and the like.

Description

Technical Field

[0001] This invention relates to the field of sheet metal processing and manufacturing technology, and in particular to a progressive forming process method. Background Technology

[0002] With the rapid growth in demand for complex curved metal components in aerospace, automotive lightweighting, and personalized medicine, traditional rigid forming methods such as stamping and molding are unable to meet the needs of small-batch, multi-variety customized production due to their high mold costs, long cycles, and poor flexibility. Incremental forming technology, as a highly flexible digital manufacturing method that does not require dedicated molds, is gradually becoming an effective means of manufacturing complex curved thin-walled parts. Although this technology has significant advantages in improving the freedom of part design and reducing mold dependence, it still faces a series of key technical challenges in the actual forming process, especially in the adaptability and reliability of sheet metal support and clamping systems. Currently widely used sheet metal clamping systems typically employ planar fixed clamps to press the metal sheet around its perimeter or edges to restrict its displacement. However, this type of clamping method has the following shortcomings: limited spatial constraint capability, increased redundancy in the forming path, limited processing quality, and poor clamping flexibility. Chinese patent CN116833293A proposes a closed-loop stretching method for a flexible stretching machine with electromagnetic clamps, using electromagnetic clamps to reduce springback during multi-point die stretching and simplifying the springback control process. Chinese patent CN114247811A proposes an externally adjustable CNC rapid reconfigurable surface mold and its forming method. This method adjusts the height of the basic unit by moving the adjusting rod assembly, thereby adjusting the mold surface of the multi-point forming module. These two technologies mainly focus on flexible design for stretch forming and multi-point mold control, but lack a systematic solution for flexible clamping and dynamic support adjustment of sheet metal in the progressive forming process. Therefore, developing a flexible clamping device for progressive forming that is height-adjustable, posture-controllable, structurally modular, and highly adaptable is of great significance for improving the forming efficiency and quality of complex curved surface parts. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a solution that improves forming quality and material utilization, increases processing efficiency and trajectory accuracy, offers high flexibility and versatility, and reduces production costs.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] The present invention provides a flexible curved surface clamping device for metal sheet in a progressive forming process, comprising a rigid base and a plurality of structurally modular clamping units distributed on the rigid base;

[0006] Each of the clamping units includes:

[0007] A height adjustment component is used to adjust the vertical height of the clamping unit;

[0008] A hinge assembly is connected to the height adjustment assembly;

[0009] The lower clamping head and the upper clamping head are mounted on the hinge assembly, which enables spatial attitude adjustment of the lower and upper clamping heads, thereby creating a flexible support surface that can adapt to complex curved contours. For sheet metal flanges with ruled surfaces, the height and angle of each unit are gradually adjusted to obtain an envelope surface consistent with the ruled surface of the flange. Then, the sheet metal is naturally fitted along the envelope surface and a fixed clamping state is applied. For flanges that are flat but have very large or even negative angles, the envelope surface is adjusted to a plane with a certain slope, and then the initial flat plate is fixedly constrained on the slope.

[0010] By independently adjusting the height of each clamping unit and the angle of the clamping head, a flexible support surface that adapts to the curved shape of the target workpiece can be constructed for fixing and clamping metal sheets.

[0011] The height of each clamping unit and the angle of the clamping head can be adjusted independently or synchronously, thereby achieving precise positioning and dynamic support control of the sheet metal before forming.

[0012] Furthermore, the hinge assembly can control the rotation angle of the lower clamping head and the upper clamping head around a set axis within a range of -40° to 40° to meet the clamping requirements of curved panel materials with different curvatures.

[0013] Furthermore, multiple clamping units are distributed along a preset array on the rigid base, and the array structure can be adjusted according to the geometry of the target sheet to adapt to forming workpieces of different shapes and sizes.

[0014] Furthermore, both the upper and lower clamping heads are equipped with replaceable contact surface modules to adapt to sheet materials of different materials or surface conditions, thereby improving clamping adaptability and forming quality.

[0015] Furthermore, the clamping unit is mounted on the rigid base via a quick-release connection structure. This facilitates rapid arrangement, disassembly, and maintenance of the device, improving the flexibility and efficiency of the clamping system.

[0016] The present invention also provides a progressive forming process method, comprising the following steps:

[0017] S1. Adjust each clamping unit to a uniform vertical height, and adjust the rotation angle of the lower clamping head and the upper clamping head to the set reference posture to form a relatively flat clamping surface.

[0018] S2. Place and clamp the metal sheet between the lower clamping head and the upper clamping head of each clamping unit; the lower clamping head and the upper clamping head are fixed together by fastening bolts;

[0019] S3. Based on the three-dimensional curved surface morphology of the target workpiece, gradually adjust the height of each clamping unit and the angle of the clamping head to guide the metal sheet to initially conform to the target morphology.

[0020] S4. Lock the position and orientation of all clamping units to construct a stable curved surface support structure;

[0021] S5. Use the progressive forming tool head to progressively form the sheet metal;

[0022] S6. After forming is complete, release the clamping force and remove the workpiece.

[0023] Furthermore, the progressive forming tool path of the progressive forming tool head is planned based on the target surface morphology and optimized in combination with the spatial distribution characteristics of the clamping unit to avoid redundant paths caused by the clamping surface limitation.

[0024] Furthermore, by adjusting the height and angle of each clamping unit, an envelope surface consistent with the flange's grain surface is obtained, and the sheet metal is naturally attached to the envelope surface and fixedly clamped.

[0025] Furthermore, the envelope surface is adjusted to a plane with a certain slope, so that the initial plate is subject to a fixed constraint on the slope.

[0026] Furthermore, the setting parameters used to adjust the clamping unit in S3 are derived from the output data of the forming simulation system of the target workpiece.

[0027] Compared with the prior art, the present invention has the following advantages:

[0028] (1) Improved forming quality and material utilization. This device can construct a three-dimensional flexible support surface that highly matches the surface morphology of the target workpiece. In traditional planar clamping, only a portion of the sheet metal participates in effective deformation when forming complex curved surfaces. However, this device pre-forms a matching support surface, allowing the initial sheet metal to conform to the target shape in a more natural and efficient manner. This increases the area of ​​the initial sheet metal participating in deformation, alleviates the sheet metal thinning caused by overall bulging, and makes the material deformation more uniform. It effectively reduces the risk of breakage caused by excessive local stretching, thereby improving the yield and material utilization. Throughout the progressive forming process, the clamping device provides stable and continuous curved surface support for the sheet metal. This support can significantly suppress elastic recovery (springback) during and after forming, ensuring forming accuracy. At the same time, it can also effectively prevent irregular local wrinkles from forming on the sheet metal under pressure, thereby obtaining higher surface quality and dimensional accuracy.

[0029] (2) Improved machining efficiency and trajectory accuracy. By actively adapting the clamping surface, the machining process is optimized, the machining path is shortened, and efficiency is improved. The machining trajectory can be significantly shortened, thereby improving the efficiency of progressive forming. Traditional planar fixtures restrict the movement space of the tool head, resulting in lengthy path planning. However, the curved support surface formed by this device is closer to the target part, and the tool head does not need to perform a lot of "idle running" or avoidance actions. The movement path is optimized and shortened, directly improving machining efficiency. The tool path can be planned based on the spatial distribution of the target curved surface and the clamping unit, avoiding interference and redundant paths caused by clamping restrictions, further improving trajectory accuracy and machining process stability.

[0030] (3) High flexibility and versatility, reducing production costs. The modular design is highly adaptable. The device consists of multiple independent units, and the array arrangement can be flexibly adjusted according to the geometry of the workpiece. By simply reconfiguring the height and angle of each unit, the same device can be used to clamp workpieces of different shapes and sizes, realizing the sharing of the same device for multiple specifications of workpieces. It reduces the dependence on special molds and saves the high cost and time of mold manufacturing, making it particularly suitable for customized product manufacturing in aerospace, personalized medicine and other fields. The device can not only form simple inclined planes or horizontal planes, but also accurately enclose ruled surfaces with convex and concave features, to meet the forming requirements of two typical complex situations - ruled surface flanges and flanges with large wall angles (even negative angles). Attached Figure Description

[0031] Figure 1 A schematic diagram of the initial clamping posture of a flexible curved surface clamping device for metal sheet in a progressive forming process.

[0032] Figure 2 A schematic diagram of the expected curved surface clamping posture of a flexible curved surface clamping device for metal sheet in a progressive forming process.

[0033] Figure 3 This is a schematic diagram of the progressive forming process of a flexible curved surface clamping device for metal sheets using a progressive forming process.

[0034] Reference numerals: 1. Height adjustment assembly, 2. Hinge assembly, 3. Lower clamping head, 4. Upper clamping head, 5. Metal sheet, 6. Fastening bolt, 7. Rigid base, 8. Progressive forming tool head. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Component models, material names, connection structures, control methods, algorithms, and other features not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0036] Example 1

[0037] This embodiment provides a flexible curved surface clamping device for metal sheet in a progressive forming process, such as... Figure 1-3 As shown, it includes a rigid base 7 and multiple modular clamping units distributed on the rigid base 7;

[0038] Each of the clamping units includes:

[0039] Height adjustment component 1 is used to realize the vertical height adjustment of the clamping unit;

[0040] Hinge assembly 2 is connected to the height adjustment assembly 1;

[0041] The lower clamping head 3 and the upper clamping head 4 are mounted on the hinge assembly 2. The hinge assembly 2 enables spatial orientation adjustment of the lower clamping head 3 and the upper clamping head 4, thereby constructing a flexible support surface that can adapt to complex curved contours. For sheet metal flanges with ruled surfaces, the height and angle of each unit are gradually adjusted to obtain an envelope surface consistent with the ruled surface of the flange. Then, the sheet metal is naturally fitted along the envelope surface and a fixed clamping state is applied. For flanges with flat surfaces but very large or even negative angles, the envelope surface is adjusted to a plane with a certain slope, and then the initial flat plate is fixedly constrained on the slope.

[0042] By independently adjusting the height of each clamping unit and the angle of the clamping head, a flexible support surface that adapts to the curved shape of the target workpiece can be constructed for fixing and clamping the metal sheet 5.

[0043] The height of each clamping unit and the angle of the clamping head can be adjusted independently or synchronously, thereby achieving precise positioning and dynamic support control of the sheet metal before forming.

[0044] This embodiment also provides a progressive forming process method, including the following steps:

[0045] S1. Adjust each clamping unit to a uniform vertical height, and adjust the rotation angle of the lower clamping head 3 and the upper clamping head 4 to the set reference posture to form a relatively flat clamping surface.

[0046] S2. Place and clamp the metal sheet 5 between the lower clamping head 3 and the upper clamping head 4 of each clamping unit; the lower clamping head 3 and the upper clamping head 4 are fixed together by fastening bolts 6;

[0047] S3. Based on the three-dimensional curved surface morphology of the target workpiece, gradually adjust the height of each clamping unit and the angle of the clamping head to guide the metal sheet 5 to initially conform to the target morphology.

[0048] S4. Lock the position and orientation of all clamping units to construct a stable curved surface support structure;

[0049] S5. Use progressive forming tool head 8 to progressively form the sheet metal;

[0050] S6. After forming is complete, release the clamping force and remove the workpiece.

[0051] Example 2

[0052] This embodiment provides a flexible curved surface clamping device for metal sheet in a progressive forming process, such as... Figure 1-3 As shown, it includes a rigid base 7 and multiple modular clamping units distributed on the rigid base 7;

[0053] Each of the clamping units includes:

[0054] Height adjustment component 1 is used to realize the vertical height adjustment of the clamping unit;

[0055] Hinge assembly 2 is connected to the height adjustment assembly 1;

[0056] The lower clamping head 3 and the upper clamping head 4 are mounted on the hinge assembly 2. The hinge assembly 2 enables spatial orientation adjustment of the lower clamping head 3 and the upper clamping head 4, thereby constructing a flexible support surface that can adapt to complex curved contours. For sheet metal flanges with ruled surfaces, the height and angle of each unit are gradually adjusted to obtain an envelope surface consistent with the ruled surface of the flange. Then, the sheet metal is naturally fitted along the envelope surface and a fixed clamping state is applied. For flanges with flat surfaces but very large or even negative angles, the envelope surface is adjusted to a plane with a certain slope, and then the initial flat plate is fixedly constrained on the slope.

[0057] By independently adjusting the height of each clamping unit and the angle of the clamping head, a flexible support surface that adapts to the curved shape of the target workpiece can be constructed for fixing and clamping the metal sheet 5.

[0058] The height of each clamping unit and the angle of the clamping head can be adjusted independently or synchronously, thereby achieving precise positioning and dynamic support control of the sheet metal before forming.

[0059] In a specific embodiment, the hinge assembly 2 can control the lower clamping head 3 and the upper clamping head 4 to rotate within a range of -40° to 40° around a set axis to meet the clamping requirements of curved panel materials with different curvatures.

[0060] In a specific embodiment, multiple clamping units are distributed along a preset array on the rigid base 7, and the array structure can be adjusted according to the geometry of the target sheet to adapt to forming workpieces of different shapes and sizes.

[0061] In a specific embodiment, both the upper clamping head 4 and the lower clamping head 3 are equipped with replaceable contact surface modules to adapt to sheet materials of different materials or surface conditions, thereby improving clamping adaptability and forming quality.

[0062] In a specific embodiment, the clamping unit is mounted on the rigid base 7 via a quick-release connection structure. This facilitates the rapid arrangement, disassembly, and maintenance of the device, improving the flexibility and efficiency of the clamping system.

[0063] The present invention also provides a progressive forming process method, comprising the following steps:

[0064] S1. Adjust each clamping unit to a uniform vertical height, and adjust the rotation angle of the lower clamping head 3 and the upper clamping head 4 to the set reference posture to form a relatively flat clamping surface.

[0065] S2. Place and clamp the metal sheet 5 between the lower clamping head 3 and the upper clamping head 4 of each clamping unit; the lower clamping head 3 and the upper clamping head 4 are fixed together by fastening bolts 6;

[0066] S3. Based on the three-dimensional curved surface morphology of the target workpiece, gradually adjust the height of each clamping unit and the angle of the clamping head to guide the metal sheet 5 to initially conform to the target morphology.

[0067] S4. Lock the position and orientation of all clamping units to construct a stable curved surface support structure;

[0068] S5. Use progressive forming tool head 8 to progressively form the sheet metal;

[0069] S6. After forming is complete, release the clamping force and remove the workpiece.

[0070] In a specific implementation, the progressive forming tool path of the progressive forming tool head 8 is planned based on the target surface topography and optimized in combination with the spatial distribution characteristics of the clamping unit to avoid redundant paths caused by the clamping surface limitation.

[0071] In a specific implementation, by adjusting the height and angle of each clamping unit, an envelope surface consistent with the flange's grain surface is obtained, and the sheet metal is naturally attached to the envelope surface around its perimeter and then fixedly clamped.

[0072] In a specific embodiment, the envelope surface is adjusted to a plane with a certain slope, so that the initial plate is subject to a fixed constraint on the slope.

[0073] In a specific implementation, the setting parameters used to adjust the clamping unit in S3 are derived from the output data of the forming simulation system of the target workpiece.

[0074] Components not described in detail in this embodiment are all existing components that can be purchased through public channels.

[0075] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A progressive forming process method, characterized in that, Includes the following steps: S1. Adjust each clamping unit to a uniform vertical height, and adjust the rotation angle of the lower clamping head (3) and the upper clamping head (4) to the set reference posture to form a relatively flat clamping surface. S2. Place and clamp the metal sheet (5) between the lower clamping head (3) and the upper clamping head (4) of each clamping unit; S3. Based on the three-dimensional curved surface morphology of the target workpiece, gradually adjust the height of each clamping unit and the angle of the clamping head to guide the metal sheet (5) to initially fit the target morphology. S4. Lock the position and orientation of all clamping units to construct a stable curved surface support structure; S5. Use the progressive forming tool head (8) to progressively form the sheet metal; S6. After forming is completed, release the clamping force and remove the workpiece; Among them, a flexible curved surface clamping device for metal sheet is used. The flexible curved surface clamping device for metal sheet includes a rigid base (7) and multiple structurally modular clamping units distributed on the rigid base (7). Each of the clamping units includes: Height adjustment component (1) is used to realize vertical height adjustment of the clamping unit; The hinge assembly (2) is connected to the height adjustment assembly (1); The lower clamping head (3) and the upper clamping head (4) are mounted on the hinge assembly (2). The space posture adjustment of the lower clamping head (3) and the upper clamping head (4) can be realized through the hinge assembly (2). By independently adjusting the height of each clamping unit and the angle of the clamping head, a flexible support surface that adapts to the curved shape of the target workpiece can be constructed for fixing and clamping the metal sheet (5).

2. The progressive forming process method according to claim 1, characterized in that, The hinge assembly (2) can control the lower clamping head (3) and the upper clamping head (4) to rotate within a range of -40° to 40° around a set axis.

3. The progressive forming process method according to claim 1, characterized in that, Multiple clamping units are distributed on the rigid base (7) in a preset array pattern, and the array structure can be adjusted according to the geometry of the target sheet.

4. The progressive forming process method according to claim 1, characterized in that, Both the upper clamping head (4) and the lower clamping head (3) are equipped with replaceable contact surface modules.

5. The progressive forming process method according to claim 1, characterized in that, The clamping unit is mounted on the rigid base (7) via a quick-release connection structure.

6. The progressive forming process method according to claim 1, characterized in that, The progressive forming tool path of the progressive forming tool head (8) is planned based on the target surface topography and optimized in combination with the spatial distribution characteristics of the clamping unit to avoid redundant paths caused by the clamping surface limitation.

7. The progressive forming process method according to claim 6, characterized in that, By adjusting the height and angle of each clamping unit, an envelope surface consistent with the flange's grain surface is obtained, and the sheet metal is naturally attached to the envelope surface and fixedly clamped.

8. The progressive forming process method according to claim 7, characterized in that, The envelope surface is adjusted to a plane with a certain slope, so that the initial plate is subject to a fixed constraint on the slope.

9. The progressive forming process method according to claim 1, characterized in that, The setting parameters used to adjust the clamping unit in S3 are derived from the output data of the forming simulation system of the target workpiece.

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