Sheet metal processing

Abstract

A shaped sheet metal structure is made of a sheet metal workpiece (1, 101). A primary anvil tool (10, 110) constrains a first surface (3, 103) of a sheet metal workpiece. The workpiece is bent to form a first substrate region (50, 150) and a second substrate region (60, 160) with a bend (56, 156) between the first substrate region (50, 150) and the second substrate region (60, 160). A first auxiliary forming tool (30) deforms the first and second side wall portions (51, 61, 151, 161) relative to the first and second base regions (50, 60, 150, 160) to form a first folded region (55, 165) in the sheet metal workpiece (1, 101) between the first side wall portion (51, 151) and the second side wall portion (61, 161). Stepwise sliding of the first auxiliary forming tool (30) along the first folding region (55, 165) causes a shear material transfer in the first folding region (55, 165) to further deform the first folding region (55, 165).

Description

Technical Field

[0001] The present invention relates to a method for processing metal sheets, and a metal sheet structure obtained by such a metal sheet processing method. The present invention also relates to a metal sheet processing apparatus. Background Art

[0002] Up to half of the metal sheets produced globally each year are not used in the final product but are cut out during the manufacturing process. Two main reasons for this loss are blanking (cutting planar shapes from the coiled long flat sheets produced by the rolling mill) and trimming after deep drawing, with the latter being the more significant reason. These losses are inevitable by-products of these processes. Further discussion and quantitative analysis of these losses can be found in the study by Horton and Allwood (2017).

[0003] Although the current blanking and deep drawing processes are considered the most effective methods for manufacturing shaped sheet metal parts such as automotive body components, the financial and carbon emission costs associated with these losses are high. A key consideration during blanking and deep drawing is to avoid wrinkling and tearing during the forming process.

[0004] WO 2020 / 043832A1 discloses a folding and shearing process by which a metal shell is made from a metal sheet. The metal shell has curved side walls that stand up from a base region, and a shrink flange and a stretch flange can be formed in the base region while minimizing thinning or unnecessary deformation as much as possible. During the formation of the stretch flange, the material located in the curved portion needs to be stretched, but in a manner that can limit thinning and edge cracking of the sheet in the curved portion. During the formation of the shrink flange, the material located in the curved portion needs to be compressed, but in a manner that can limit thickening and buckling / wrinkling of the sheet in the curved portion. In WO2020 / 043832, this is achieved by shear material transfer during the processing.

[0005] In WO2020 / 043832, the base of the shell is planar, and the side walls stand up from the base. Therefore, a shrink flange and a stretch flange are formed and shearing is required only when the curved side walls stand up from the base.

[0006] However, the present inventors have realized that there is also a need to form a metal housing having a non-planar base. The difficulty in forming such a metal housing is that, even when there are no curved sidewalls and thus no shrink flanges or stretch flanges as in WO2020 / 043832, the act of bending the sidewalls to rise up from the non-planar base creates potential shrinkage and stretch regions in adjacent areas of the sidewalls, which extend from non-coplanar adjacent base regions. When using known metal sheet processing devices, the shrinkage and stretch regions on the sidewalls are prone to buckling / wrinkling and tearing respectively.

[0007] The present invention is designed based on the above considerations. Summary of the Invention

[0008] In a first aspect, a method of manufacturing a formed metal sheet structure is provided. The method includes the following steps: providing a metal sheet workpiece having opposite first and second surfaces and at least one edge; providing a main anvil tool having a tool surface for contacting and constraining at least a portion of the first surface of the metal sheet workpiece; bending the workpiece to form at least a first base region and a second base region with a bend therebetween, and constraining at least a portion of the base regions between the main anvil tool and a main forming tool to fix the base regions relative to the main anvil tool, with a first sidewall portion extending between the first base region and the edge and a second sidewall portion extending between the second base region and the edge; providing a first auxiliary forming tool having a tool surface for contacting and constraining at least a portion of the second surface of the metal sheet workpiece; bringing the metal sheet workpiece into contact with the first auxiliary forming tool to deform the first sidewall portion and the second sidewall portion relative to the first base region and the second base region, thereby forming a first folding region in the metal sheet workpiece between the first sidewall portion and the second sidewall portion; and gradually sliding the first auxiliary forming tool along the first folding region to cause shear material transfer in the first folding region, thereby further deforming the first folding region.

[0009] The method of manufacturing a formed metal sheet structure according to the first aspect allows the formation of sidewalls extending from a non-planar base within the metal sheet structure while reducing the risk of material buckling, wrinkling, or tearing in the folding regions of the sidewalls. The folding region can be formed near the bend, with the first surface of the workpiece being concave at the first bend. The steps of the method according to the first aspect can be performed in the order listed above.

[0010] The method may further include the following steps: providing a first auxiliary anvil tool having a tool surface for contacting and constraining at least a portion of the first surface of the sheet metal workpiece at the first folding region. Providing the first auxiliary anvil tool allows for better control of the shear material transfer of the material outward from the folding region in the step of gradually sliding the first auxiliary forming tool along the first folding region. Constraining the first surface of the workpiece in the first folding region with the first auxiliary anvil tool also reduces the possibility of buckling / wrinkling in the folding region.

[0011] The step of bringing the sheet metal workpiece into contact with the main anvil tool and the first auxiliary forming tool may be performed such that a clamping pressure greater than or equal to 100 kPa is applied to the portion of the sheet metal workpiece between the corresponding tool surfaces of the first auxiliary forming tool and the first auxiliary anvil tool. Applying sufficient pressure to the portion of the workpiece clamped between the first auxiliary forming tool and the first auxiliary anvil tool facilitates improving the shear material transfer in the step of sliding the first auxiliary forming tool along the first folding region. The clamping pressure may be appropriately adjusted according to the material and thickness of the workpiece.

[0012] The method may further include the following steps: gradually sliding the first auxiliary anvil tool along the first folding region. In this case, the step of gradually sliding the first auxiliary anvil tool along the first folding region may be performed simultaneously with the step of sliding the first auxiliary forming tool along the first folding region to control the deformation of the first folding region. Advantageously, simultaneously sliding the first auxiliary forming tool and the first auxiliary anvil tool along the first folding region improves the shear material transfer of the material outward from the folding region and reduces the possibility of buckling / wrinkling in the folding region. In fact, the first auxiliary anvil tool and the first auxiliary forming tool together provide a moving constraint to constrain the material of the workpiece in the folding region to reduce buckling / wrinkling. As understood, it is intended that the first auxiliary forming tool slides along the second surface of the workpiece and the first auxiliary anvil tool slides along the first surface of the workpiece.

[0013] The step of gradually sliding the first auxiliary anvil tool along the first folding region may be achieved by gradually sliding the first auxiliary forming tool along the first folding region. This provides a simple way in which it is ensured that the first auxiliary forming tool and the first auxiliary anvil tool move in cooperation, for example, at the same speed (same rate and direction), improving the shear material transfer of the material outward from the folding region and reducing the possibility of buckling / wrinkling in the folding region.

[0014] The main anvil tool and the first auxiliary anvil tool may be respectively connected to a first pressure plate. In this case, at least one of the main anvil tool and the first auxiliary anvil tool may be movably connected to the first pressure plate. Advantageously, this configuration allows the main anvil tool and the first auxiliary anvil tool to move together like a single tool or independently of each other.

[0015] The main anvil tool may include a sidewall. In this case, in the step of bringing the sheet metal workpiece into contact with the first auxiliary forming tool, the sidewall of the main anvil tool may restrain at least a portion of the first surface of the first sidewall portion of the workpiece and at least a portion of the first surface of the second sidewall portion of the workpiece. Further, in the step of sliding the first auxiliary forming tool along the first folding region, the sidewall of the main anvil tool may restrain at least a portion of the first surface of the first folding region. Thus, the sidewall of the main anvil tool can be used to restrain the deformation of the workpiece and reduce the likelihood of tearing and / or buckling the workpiece during workpiece deformation. The sidewall of the main anvil tool may be substantially planar.

[0016] The step of bending the workpiece to form the first base region and the second base region may be performed by the step of clamping the sheet metal workpiece between the corresponding tool surfaces of the main anvil tool and the main forming tool. The advantage of performing the bending step in this manner is that the bend formed in the workpiece will exactly conform to the shape of the corresponding tool surfaces of the main anvil tool and the main forming tool.

[0017] The step of clamping the sheet metal workpiece between the main anvil tool and the main forming tool may be performed such that a clamping pressure greater than or equal to 100 kPa is applied to the portion of the sheet metal workpiece between the corresponding tool surfaces of the main anvil tool and the main forming tool. Advantageously, applying sufficient pressure to the portion of the workpiece clamped between the main anvil tool and the main forming tool enhances the plastic deformation of the workpiece during the bending step. The clamping pressure may be set to balance the elastic recovery of the workpiece with the thinning of the workpiece caused by clamping and subsequent deformation.

[0018] In the following steps, the sheet metal workpiece may remain clamped between the main anvil tool and the main forming tool: bringing the sheet metal workpiece into contact with the main anvil tool and the first auxiliary forming tool to deform the first sidewall portion and the second sidewall portion; and gradually sliding the first auxiliary forming tool along the first folding region. Advantageously, clamping the workpiece between the main anvil tool and the main forming tool prevents the base region from moving during subsequent deformation steps.

[0019] The main forming tool and the first auxiliary forming tool may be respectively connected to a second platen, and at least one of the main forming tool and the first auxiliary forming tool may be movably connected to the second platen. Advantageously, this configuration allows the main forming tool and the first auxiliary forming tool to move together as a single tool or independently of each other.

[0020] The method further comprises the following steps: bending the workpiece to form a third base region, with a second bending portion between the second base region and the third base region, and a third sidewall portion extending between the third base region and the edge. Then, the step of bringing the sheet metal workpiece into contact with the first auxiliary forming tool can also cause the third sidewall portion to deform relative to the third base region, thereby forming a second folding region in the sheet metal workpiece between the second sidewall portion and the third sidewall portion. Then, the method can further comprise the step of gradually sliding the first auxiliary forming tool along the second folding region to further deform the second folding region.

[0021] The first sidewall portion and the second sidewall portion can be provided on the first side of the base region. Then, a fourth sidewall portion can extend between the first base region and the edge of the sheet metal workpiece on the other side of the base region, and a fifth sidewall portion can extend between the second base region and the edge. In this case, the method can subsequently further comprise the following steps: providing a second auxiliary forming tool having a tool surface for contacting and constraining at least a portion of the second surface of the sheet metal workpiece; bringing the sheet metal workpiece into contact with the second auxiliary forming tool to cause the fourth sidewall portion and the fifth sidewall portion to deform relative to the first base region and the second base region, thereby forming a third folding region in the sheet metal workpiece between the fourth sidewall portion and the fifth sidewall portion; and gradually sliding the second auxiliary forming tool along the third folding region to cause shear material transfer in the third folding region, thereby further deforming the third folding region. Advantageously, the method can be used to form an angular sheet metal structure or a channel-shaped sheet metal structure.

[0022] The second auxiliary forming tool is integrally formed with the first auxiliary forming tool. Therefore, during the execution of the method, fewer forming tools need to be independently controlled, and since the forming tools are tightly combined by integral forming, the distance between the tools can be more strictly controlled, thereby making the deformation caused by the tools more precise.

[0023] In a second aspect, there is provided a workpiece obtained or obtainable using the method according to the first aspect.

[0024] In a third aspect, there is provided a sheet metal processing apparatus suitable for performing the method of manufacturing a formed sheet metal structure according to the first aspect.

[0025] In a fourth aspect, there is provided a sheet metal working apparatus for manufacturing a formed sheet metal structure from a sheet metal workpiece. The sheet metal workpiece has opposite first and second surfaces and at least one edge. The formed sheet metal structure to be manufactured has at least a first base region and a second base region, with a bend between the first base region and the second base region, a first sidewall portion extending between the first base region and the edge, and a second sidewall portion extending between the second base region and the edge. The sheet metal working apparatus includes: a main anvil tool having a tool surface for contacting and constraining at least a portion of the first surface of the sheet metal workpiece; a main forming tool, the main forming tool and the main anvil tool for constraining at least a portion of the base region; a first auxiliary forming tool having a tool surface for contacting and constraining at least a portion of the second surface of the sheet metal workpiece. The first auxiliary forming tool is for contacting the sheet metal workpiece to deform the first sidewall portion and the second sidewall portion relative to the first base region and the second base region, so as to form a first folding region in the sheet metal workpiece between the first sidewall portion and the second sidewall portion. The first auxiliary forming tool is further for sliding along the first folding region to cause shear material transfer in the first folding region, thereby further deforming the first folding region.

[0026] The above method (also referred to herein as the "Folding-Shearing" method) can produce a formed sheet metal structure which, compared to producing the same part by, for example, a drawing process, requires minimal or no trimming after forming. Additionally, the above method can not only reduce metal waste but also maintain a satisfactory sheet quality (e.g., reducing or avoiding unnecessary material deformation such as wrinkling or tearing).

[0027] The exact shape of the bent base and the one or more sidewalls extending therefrom is not particularly limited and can take many different forms depending on the specific forming process and the desired final shape of the product. In some embodiments, the sidewalls can be substantially planar, while in other embodiments, both the base and the sidewalls can be curved. In some embodiments, the sidewalls extend substantially perpendicularly from the base, while in other embodiments, the sidewalls can be at different angles to the base.

[0028] The term "base region" is used herein to define a region of the sheet metal workpiece that is a planar, base-like region. During the forming process, the base region may undergo little or no bending and / or deformation. In other words, the base region can be the region where the original dimensions and shape of the workpiece remain unchanged during the forming operation. In some alternative forming processes, the base region may undergo some shear deformation. The dimensions and shape of the base region are not particularly limited and can be appropriately selected given the expected form of the formed sheet metal structure.

[0029] In the step of gradually sliding the forming tool along the folding region, the exact nature of the further deformation of the folding region is not particularly limited and will depend on the specific forming process and the desired final shape of the product. Shear material transfer in the folding region can occur via material transfer from the folding region to at least one sidewall portion and / or material transfer from at least one sidewall portion to the folding region. However, in some embodiments, shear material transfer in the folding region can additionally or alternatively occur by shear material transfer to or from the base region of the sheet.

[0030] Material transfer from the folding region to at least one sidewall portion can improve the formation of the sidewall, wherein the first surface of the sheet is concave between adjacent base regions. By allowing such material transfer, a formed sheet metal structure with a non-planar base of various shapes can be produced, with little or no material thinning or thickening of the sidewalls, thereby helping to reduce the occurrence of wrinkling and / or tearing during the forming process.

[0031] The anvil tool and / or the forming tool can include a circular tool surface. The circular tool surface of the anvil tool can be complementary to the circular tool surface of the forming tool. For example, the curvature of the circular tool surface of the anvil tool can be opposite to the curvature of the circular tool surface of the forming tool.

[0032] The terms "sidewall" and "sidewall portion" are used herein with respect to the workpiece to generally define the portions of the workpiece that form the sidewalls relative to the base region of the sheet. In other words, it is a part of the sheet that is inclined relative to the base region of the sheet or is intended to be inclined relative to the base region of the sheet during manufacturing to form the sidewalls. The bending / folding performed to form such sidewall portions can be partially elastic or fully plastic. In some cases, the folding can occur along a folding line near the base region of the sheet. Such a folding line can define the edge of the base region. The number of sidewall portions can be selected according to the desired final shape of the given formed sheet metal structure. As described above, there can be at least a first sidewall portion and a second sidewall portion. Preferably, the sidewall portions extend from the base region (e.g., from the folding line defining the edge of the base region) to the edge of the sheet metal workpiece.

[0033] The term "curved" is considered synonymous with "circular" and is generally used to refer to a region having a certain degree of curvature. The curvature can vary throughout the region. Thus, the terms curved or circular are not used herein to refer only to regions of constant curvature (i.e., they should not be limited to cylindrical or spherical regions).

[0034] Preferably, the metal sheet processing apparatus can be retrofitted to an existing stamping production line. For example, the bending stage can be performed by existing tools that are currently partially used in the drawing process.

[0035] Preferably, the main anvil tool and the first auxiliary anvil tool, as well as the main forming tool and the first auxiliary forming tool, can be interchanged with other anvil tools and other forming tools respectively.

[0036] In a fifth preferred aspect, the present invention provides a kit including the metal sheet processing apparatus of the third or fourth aspect, and one or more other anvil tools and one or more other forming tools.

[0037] The present invention includes combinations of the described aspects and optional features, unless such combinations are clearly infeasible or explicitly excluded. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Examples illustrating the principles of the present invention will now be discussed with reference to the accompanying drawings, in which:

[0039] Figures 1A to 1F Shows consecutive process steps in a method of manufacturing a formed metal sheet structure having a non-planar base and side walls extending therefrom;

[0040] Figures 2A to 2F Shows consecutive process steps in a method of manufacturing a formed metal sheet structure having a non-planar base and side walls extending therefrom, and some of the metal sheet processing apparatuses used in the method;

[0041] Figures 3A to 3F Shows consecutive process steps in a method of manufacturing a formed metal sheet structure having a non-planar base and side walls extending therefrom, and the metal sheet processing apparatuses used in the method;

[0042] Figures 4A to 4E Shows consecutive process steps in a method of manufacturing a formed metal sheet structure having a non-planar base and side walls extending therefrom, and some of the metal sheet processing apparatuses used in the method. DETAILED DESCRIPTION

[0043] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying drawings. Other aspects and embodiments will be apparent to those skilled in the art. All documents mentioned herein are incorporated herein by reference.

[0044] The process described herein can be understood as "fold shear". This process can be used to deform a metal sheet blank into a shell shape (such as a can body, a box body, or a vehicle body part) currently manufactured by drawing, and reduce the need for trimming after forming.

[0045] The process will now be described with reference to FIGS. 1 to 4, each of which includes a plurality of sub - figures showing the shape of the sheet metal structure at different stages of the process of forming a sheet metal structure by "fold - shear", and in some cases the shape and position of the sheet metal processing apparatus.

[0046] Figures 1A to 1F The shape of the sheet metal structure 1 at successive stages in this "fold - shear" process is shown in sequence.

[0047] As Figure 1A shown, the process initially starts with a planar sheet metal, and as Figure 1F shown, the final formed sheet metal structure includes planar side walls extending downwardly from the non - planar base of the workpiece at approximately 90°.

[0048] In the first stage of the manufacturing process, a planar sheet metal workpiece 1 as Figure 1A shown is provided. The sheet metal workpiece has opposite first surface 3 and second surface 5, where the first surface is the lower surface (not shown) of the sheet metal and the second surface is the upper surface of the sheet metal. The sheet has an outer peripheral edge 7. The shape of the sheet metal workpiece 1 and the one or more outer peripheral edges 7 it has are not essential and can be appropriately selected based on the shape of the formed sheet metal structure desired to be produced. The sheet metal workpiece 1 is located in a sheet metal processing apparatus ( Figures 1A to 1F not shown in the figure).

[0049] Figure 1B shows the step of bending the workpiece 1 to form a first base region 50 and a second base region 60, the first base region 50 and the second base region 60 together forming the base of the workpiece 1. The first base region 50 and the second base region 60 are each substantially planar, but are separated by a bend 56 therebetween. In Figure 1B the figure, the bending of the workpiece 1 is such that the first surface 3 of the workpiece 1 is concave between the first base region 50 and the second base region 60, that is, the angle perpendicular to the first surface 3 between the base regions 50, 60 is less than 180°. Extending from the first base region 50 is a first side wall portion 51, and the first side wall portion 51 extends to the outer peripheral edge 7 of the workpiece 1. Similarly, extending from the second base region 60 is a second side wall portion 61, and the second side wall portion 61 also extends to the outer peripheral edge 7 of the workpiece 1. At the stage shown in Figure 1B the figure, the first side wall portion 51 and the second side wall portion 61 remain coplanar with their respective base regions 50, 60, but the first side wall portion 51 and the second side wall portion 61 are not coplanar and have been bent as part of the step of forming the first base region 50 and the second base region 60.

[0050] As Figure 1CAs shown, in subsequent steps of the process, the first sidewall portion 51 and the second sidewall portion 61 are deformed relative to the first base region and the second base region such that the first sidewall portion 51 and the second sidewall portion 61 are no longer coplanar with the respective base regions 50, 60. In Figure 1C the case of, the sidewall portions 51, 61 are deformed downward such that the first surface 3 of the workpiece 1 is concave between the base and the sidewalls (i.e., the angle between the first surface 3 in the first base region 50 and the first surface 3 in the first sidewall portion 51 is less than 180°, and the angle between the first surface 3 in the second base region and the first surface 3 in the second sidewall portion 61 is less than 180°). A sidewall bend 57 is formed between the base regions 50, 60 and the sidewall portions corresponding to the base regions 50, 60. During the process of deforming the first sidewall portion 51 and the second sidewall portion 61, a folding region 55 corresponding approximately to the bend 56 is formed. In Figures 1A to 1F the workpiece 1 in, the bend 56 is concave with respect to the first surface 3, and thus the folding region 55 is a region in the workpiece where there will be excess material when the sidewall portions 51, 61 are deformed. Figures 1C to 1F The folding region 55 in is a region where buckling / wrinkling is likely to occur without adopting this method.

[0051] Figure 1D shows a stage of the process in which most of each of the sidewall portions 51, 61 has been deformed and is now at the desired angle relative to the base regions 50, 60, which is approximately 90° when measured from the first surface 3 of the workpiece 1 in Figure 1D . These regions of the sidewall portions 51, 61 can be referred to as "developable regions". However, the folding region 55 contains non-developable regions of the sidewall portions 51, 61, forming a raised "beak" shape, where the sidewalls are not developed because the surface area required for the shape changes when transitioning from the undeformed sidewall state shown in Figure 1B to the deformed sidewall state shown in Figure 1F . In the workpiece at the stage shown in Figure 1D , the formation of the folding region 55 causes the metal in the folding region 55 to undergo a minimal amount of stretching and / or compression. Deforming the sidewall portions 51, 61 to the stage shown in Figure 1D does not cause a change in the thickness of the workpiece 1, or only causes a minimal change, such as not exceeding approximately ±10%. To provide the final formed metal sheet structure shown in Figure 1F , further deformation of the folding region 55 is required to eliminate the raised portion of the folding region 55 and to make the folding region 55 conform to the deformed sidewall portions 51, 61; however, this further deformation is likely to cause buckling / wrinkling of the metal sheet workpiece 1 in the folding region 55 due to the reduction in the required surface area.

[0052] In subsequent steps of the manufacturing process, a forming tool (not shown) slides step by step along the folding region 55 to induce shear material transfer therein, thereby further deforming the folding region 55 without buckling / wrinkling the workpiece 1 in this region. Figure 1E A stage of the process with this step partially completed is shown. Figure 1D The upper part of the raised folding region 55 present in Figure 1E has been flattened to form the sidewalls and has not wrinkled / buckled due to shear material transfer in the folding region, where material is transferred from the folding region to at least one sidewall portion. In Figure 1E the lower part of the folding region 55 remains raised and further shear material transfer is required so that the folding region 55 is aligned with the unfolded sidewall portions 51, 61.

[0053] Figure 1F The formed sheet metal structure at the end of the manufacturing process is shown in Figure 1F including continuous sidewalls extending downward from the base, the base being non-planar (i.e., having two non-coplanar base regions), but the sidewalls extending from this base are substantially planar on the sidewall portions 51, 61 (at least in the case of the example shown in Figure 1F ). Although the sidewalls in Figure 1F are substantially planar on the sidewall portions 51, 61, the sidewalls formed according to the present method can be non-planar on the sidewall portions 51, 61; however, the greater the degree of deviation of the sidewall portions from the plane, the greater the amount of stretching or shrinking of the workpiece that the process needs to accommodate. Here, the plane of the sidewalls and the plane of the base regions are both offset by approximately 90°. Advantageously, compared to producing the same component via, for example, a drawing process,

[0054] Figures 2A to 2F The shapes of the sheet metal workpiece 1 at successive stages in this “fold-shear” process and the interaction of the sheet metal workpiece 1 with some of the sheet metal processing devices that can be used in this process are shown in sequence. In particular, the features of the main anvil tool and the first auxiliary anvil tool are shown in addition to the workpiece.

[0055] Figures 2A to 2F The shape of the sheet metal structure 1 in each of the figures of Figures 1A to 1F is the same as the shape of the sheet metal structure 1 in each of the figures of Figures 2A to 2F Therefore, a detailed discussion of the shape of the sheet metal structure 1 in each of the figures of

[0056] In Figure 2A , a main anvil tool 10 is provided for forming a sheet metal structure. The main anvil tool 10 has a tool surface 15 (partially obscured by the sheet metal workpiece 1 in Figure 2A ), which contacts the first (lower) surface 3 of the sheet metal workpiece 1 to constrain at least a portion of the first surface 3. In Figure 2A , the tool surface 15 of the main anvil tool 10 is the upper surface of the anvil tool 10. The main anvil tool 10 further includes side walls 16 extending from the tool surface 15, and in Figure 2A , the edges where the side walls 16 and the tool surface 15 intersect are beveled to assist in the smooth deformation of the side wall portions 51, 61 in subsequent steps of the process. Figure 2A A first auxiliary anvil tool 20 is also shown in Figures 2D to 2F , which also has a tool surface 25 for contacting and constraining at least a portion of the first (lower) surface 3 of the sheet metal workpiece 1. As described below with respect to Figures 2D to 2F , the manufacturing process can utilize the first auxiliary anvil tool 20 to exert greater control over the forming of the sheet metal workpiece 1; however, the process can also be carried out without the first auxiliary anvil tool 20.

[0057] In the presence of the main anvil tool 10 and the first auxiliary anvil tool 20, both the main anvil tool 10 and the first auxiliary anvil tool 20 can be connected to a first platen for attachment to a metal forming press. As described below with respect to Figure 2E , the first auxiliary anvil tool 20 is movable relative to the main anvil tool 10; thus, when the main anvil tool 10 and the first auxiliary anvil tool 20 are connected to the first platen, at least one of the anvil tools 10, 20 is movably connected to the first platen. The movable connection of the anvil tool to the first platen can be achieved, for example, by a hydraulic actuated punch or a mechanically actuated punch.

[0058] In Figure 2B , the sheet metal workpiece 1 has been bent to form a first base region 50 and a second base region 60 as discussed above with respect to Figure 1B . Figure 2B It is shown how the workpiece 1 is bent to form the first base region 50 and the second base region 60 such that when the first surface 3 of the bent workpiece 1 contacts the tool surface 15 of the main anvil tool 10, the first base region 50 and the second base region 60 are aligned with at least a portion of the tool surface 15, such that the tool surface 15 constrains the base regions 50, 60 against further deformation. The first auxiliary anvil tool 20 is disposed near the side wall 16 of the main anvil tool 10 and is generally in the shape of an oblique triangular pyramid, optionally truncated, where its apex is laterally aligned with the bend 56.

[0059] As Figure 2C shown, in a subsequent step of the process, the first sidewall portion 51 and the second sidewall portion 61 are deformed relative to the first base region 50 and the second base region 60 such that the first sidewall portion 51 and the second sidewall portion 61 are no longer coplanar with the respective base regions 50, 60. A sidewall bend 57 that conforms to the bevel is formed between the tool surface 15 of the main anvil tool and the sidewall 16. The first sidewall portion 51 and the second sidewall portion 61 are deformed around the edge between the tool surface 15 and the sidewall 16 of the main anvil tool 10 such that the developable regions of the sidewall portions 51, 61 of the sheet metal workpiece 1 approach the sidewall 16 of the main anvil tool 10. When the sidewall portions 51, 61 are deformed, a folded region 55 corresponding to the bend 56 is formed due to the presence of excess material in the workpiece at this location. This deformation continues until reaching Figure 2D the stage shown, in which the developable regions of the sidewall portions 51, 61 have been deformed and the first surface 3 in these regions is now in contact with and constrained by the sidewall 16 of the main anvil tool 10. In Figure 2D the main anvil tool 10 shown, the sidewall 16 is substantially perpendicular to the tool surface 15 and thus Figure 2D the developable regions of the sidewall portions 51, 61 at the stage shown are substantially perpendicular to the base regions 50, 60. However, the angle of the sidewall 16 relative to the tool surface 15 is not particularly limited and can be set to provide the desired angle between the base and the sidewall in the formed sheet metal structure. The deformation of the sidewall portions 51, 61 is achieved by bringing the sheet metal workpiece into contact with the main anvil tool 10 and a first auxiliary forming tool (not shown).

[0060] Figure 2D It is also shown that at least a portion of the first surface 3 of the sheet metal workpiece 1 has come into contact with and is constrained by the tool surface 25 of the first auxiliary anvil tool 20 in the folded region 55. The folded region 55 is supported by the first auxiliary anvil tool 20 such that when the sidewall portions 51, 61 are deformed, no deformation that causes buckling / wrinkling of the sheet metal workpiece 1 occurs in the folded region 55. Generally, the first auxiliary anvil tool 20 prevents buckling in the folded region 55 by providing the tool surface 25 that constrains the folded region 55 such that the degree of tension and / or compression of the material in the folded region 55 is minimized during the deformation of the sidewall portions 51, 61 and such that the thickness of the sheet metal workpiece 1 does not substantially change (i.e., from Figure 2B the stage shown to Figure 2D the stage shown, the thickness of the sheet metal workpiece 1 does not change or changes minimally, for example, by no more than about ±10%).

[0061] Then, Figure 2Eshows a part of a subsequent step in the manufacturing process of workpiece 1, in which a first auxiliary forming tool (not shown) slides step by step along the folding region 55, causing shear material transfer therein and bringing the folding region 55 into alignment with the unfolded regions of the side wall portions 51, 61. In order to bring the folding region 55 into alignment with the unfolded regions of the side wall portions 51, 61 - for example, as Figure 2F shown, bringing the folding region 55 into coplanar with the unfolded regions of the side wall portions 51, 61 - without buckling / wrinkling the material in the folding region 55, shear material transfer is required, where material is transferred from the folding region 55 into at least one of the side wall portions and possibly transferred to one or both of the side wall portions 51, 61 and / or to the base regions 50, 60 adjacent to the folding region 55. In Figure 2D , the folding region 55 is constrained by the tool surface 25 of the first auxiliary anvil tool 20, and thus the folding region 55 cannot be aligned with the adjacent side wall portions 51, 61. In order to deform the folding region 55, the first auxiliary anvil tool 20 must be withdrawn from below the folding region 55 so that it no longer constrains the entire folding region 55.

[0062] To achieve controlled deformation of the folding region 55, while the first auxiliary forming tool (not shown) slides along the folding region 55, the first auxiliary anvil tool 20 is withdrawn from below the folding region 55 such that at a given time, only a small portion of the folding region 55 that is not constrained by the first auxiliary anvil tool 20 can be deformed by the first auxiliary forming tool. Through shear material transfer, from the folding region 55 to the side wall portions 51, 61 (and possibly the adjacent base regions 50, 60), the portion of the folding region 55 that is not constrained by the first auxiliary anvil tool 20 is brought into alignment with the unfolded regions of the adjacent side wall portions 51, 61. In Figure 2E , the controlled deformation portion of the folding region 55 is completed, Figure 2D the upper part of the raised folding region 55 present in Figure 2E has been flattened to be aligned with the unfolded side wall portions 51, 61 without buckling / wrinkling. In Figure 2E , relative to the main anvil tool 10 and the workpiece 1, the first auxiliary anvil tool 20 is lower than its position in Figure 2D .

[0063] This sliding step continues such that the size of the raised portion of the folding region 55 gradually decreases until the material in the folding region 55 is fully stretched by the forming tool and reaches the Figure 2F shape of the formed sheet metal structure shown in Figure 2F The formed sheet metal structure inFigure 2F In the example shown). Here, the plane of the side wall and the plane of the base region are both offset by approximately 90°. Advantageously, compared to producing the same part, for example, via a deep drawing process, Figure 2F the formed sheet metal structure at the end of the manufacturing process shown in requires minimal or no trimming after forming. Additionally, the above method can not only reduce metal waste but also maintain satisfactory sheet quality (e.g., reduce or avoid unnecessary material deformation such as wrinkling or tearing).

[0064] Figures 3A to 3F The shape of the sheet metal workpiece 1 at each successive stage in this "fold and shear" process and the interaction of the sheet metal structure 1 with some of the sheet metal processing devices that can be used in this process are shown in sequence.

[0065] Figures 3A to 3F The shape of the sheet metal structure 1, the main anvil tool 10, and the first auxiliary anvil tool 20 in is the same as Figures 1A to 1F and Figures 2A to 2F The shape of the sheet metal structure 1, the main anvil tool 10, and the first auxiliary anvil tool 20 in. Therefore, a detailed discussion of the shape of the sheet metal structure 1, the main anvil tool 10, and the first auxiliary anvil tool 20 in each figure of Figures 3A to 3F is omitted here.

[0066] In Figure 3A a first auxiliary forming tool 30 is provided for forming the sheet metal structure. The first auxiliary forming tool 30 has a tool surface 35 that contacts the second (upper) surface 5 of the sheet metal workpiece 1 to constrain at least a portion of the second surface 5. In Figure 3A the tool surface 35 is the lower surface of the forming tool 30. Figure 3A The main forming tool 40 is also shown in, and the main forming tool 40 also has a tool surface 45 for contacting and constraining at least a portion of the second (upper) surface 5 of the sheet metal workpiece 1. The tool surface 15 of the main anvil tool 10 and the tool surface 45 of the main forming tool 40 are shaped to be generally consistent with each other. As described below with respect to Figure 3A and 3B the manufacturing process can utilize the main forming tool 40 to exert greater control over the forming of the sheet metal workpiece.

[0067] In the presence of the main forming tool 30 and the first auxiliary forming tool 40, both the main forming tool 30 and the first auxiliary forming tool 40 can be connected to the second platen to be attached to the metal forming press. As described below with respect to Figure 3B and Figure 3CAs described, the main forming tool 40 is movable relative to the first auxiliary forming tool 30; thus, when the main forming tool 30 and the first auxiliary forming tool 40 are connected to the second pressure plate, at least one of the forming tools 30, 40 is movably connected to the second pressure plate. The movable connection of the forming tool to the second pressure plate can be achieved, for example, by a hydraulically actuated punch or a mechanically actuated punch.

[0068] Between Figure 3A and Figure 3B the stages shown, Figure 3A the flat sheet metal workpiece 1 therein is bent to form a first base region 50 and a second base region 60, and the first base region 50 and the second base region 60 together form the base of the workpiece 1. Between Figure 3BIn this case, the base of workpiece 1 is clamped between the main anvil tool 10 and the main forming tool 40, such that the base is fixed in position relative to the main anvil tool 10 and the main forming tool 40. This ensures that the sheet metal workpiece 1 is fixed before subsequent forming steps, meaning that the base regions 50, 60 cannot move relative to the main anvil tool 10, thereby preventing incorrect deformation of the sheet metal workpiece due to movement of the base region during subsequent process steps. The step of bending workpiece 1 to form the first base region 50 and the second base region 60 can be carried out by the step of clamping workpiece 1 between the corresponding tool surfaces 15 of the main anvil tool 10 and the corresponding tool surfaces 45 of the main forming tool 40. The advantage of carrying out the bending step in this way is that the bend 56 formed in the sheet metal workpiece 1 will exactly conform to the shape of the corresponding tool surfaces 15, 45. The step of clamping the base of workpiece 1 between the main anvil tool 10 and the main forming tool 40 is achieved by moving the main anvil tool 10 and the main forming tool 40 towards each other with workpiece 1 located therebetween. The main anvil tool 10 and the main forming tool 40 come into contact with workpiece 1 and continue to move towards each other until the base regions 50, 60 come into contact with the tool surfaces 15, 45 and conform to the tool surfaces 15, 45. The main anvil tool 10 and the main forming tool 40 continue to move towards each other until the clamping pressure applied to the portion of the sheet metal workpiece 1 between the corresponding tool surfaces 15, 45 of the tools 10, 40 is greater than or equal to a first threshold clamping pressure. The first threshold clamping pressure can be set according to the Young's modulus and yield stress of the material of the sheet metal workpiece 1, and thereby determines the magnitude of the pressure to be applied to workpiece 1 during subsequent forming steps in the manufacturing process. Generally, the first threshold clamping pressure is greater than or equal to 100 kPa. Optionally, the clamping pressure should not exceed the yield stress of the material forming workpiece 1, as too large a clamping pressure may cause unnecessary thinning and tearing of parts of the workpiece. A clamping pressure exceeding the yield stress of the material forming workpiece 1 may cause unnecessary and excessive forging of the workpiece. In practice, the upper limit of the clamping pressure can be set according to the upper limit of the gas spring or hydraulic buffer applying the clamping pressure.

[0069] As Figure 3B shown, the side wall portions 51, 61 of workpiece 1 extend to one side of the portion where workpiece 1 is clamped between the main anvil tool 10 and the main forming tool 40, wherein the first auxiliary anvil tool 20 is located below the side wall portions 51, 61.

[0070] In subsequent steps of the process, as Figure 3C and 3D shown (roughly corresponding to Figure 1C and 2Cthe shape of the workpiece 1 in), the first auxiliary forming tool 30 contacts the first side wall portion 51 and the second side wall portion 61, causing the first side wall portion 51 and the second side wall portion 61 to deform relative to the first base region 50 and the second base region 60. Specifically, Figure 3C shows a point in the manufacturing process: the first auxiliary forming tool is located above the second surface 5 of the workpiece 1 and moves downward relative to the workpiece 1 and the main anvil tool 10, such that the tool surface 35 of the first auxiliary forming tool 30 contacts the second surface 5 of the workpiece. Then, Figure 3D shows how the forming tool 30 continues to move downward and, in the process, deforms the side wall portions 51, 61, thereby reducing the angle between the first surface 3 in each of the side wall portions 51, 61 and the first surface 3 in the corresponding base regions 50, 60 of the side wall portions. A side wall bend 57 is formed that is consistent with the hypotenuse between the tool surface 15 and the side wall 16 of the main anvil tool. During the process of deforming the side wall portions 51, 61, a folded region 55 begins to form between the first side wall portion 51 and the second side wall 61 in the workpiece 1.

[0071] At Figure 3E the stage, which roughly corresponds to Figure 1D and Figure 2D the shape of the workpiece 1 in, the deployable regions of the side wall portions 51, 61 have been deformed by the first auxiliary forming tool 30 and contact and are constrained by the side wall 16 of the main anvil tool (see Figure 2D ). Figures 3A to 3F The tool surface 35 of the first auxiliary forming tool 30 in also includes an inverted "v" shaped portion, as Figure 3EAs shown, this part is aligned with the shape of the tool surface 25 of the first auxiliary anvil tool 20. When the side wall parts 51, 61 are deformed by the relative movement of the first auxiliary forming tool 30 and the workpiece 1, a folded area 55 forms a protruding beak shape, and this protruding beak shape contacts and is constrained by the inverted "v" shaped part of the tool surface 35 of the first auxiliary forming tool 30 and the tool surface 25 of the first auxiliary anvil tool 20. The first auxiliary forming tool 30 continues to move downward until the folded area 55 is between the first auxiliary forming tool 30 and the first auxiliary anvil tool 20 and is in full contact with the first auxiliary forming tool 30 and the first auxiliary anvil tool 20. The downward movement of the forming tool 30 relative to the workpiece 1 and the first auxiliary anvil tool 20 clamps the folded area 55 between the corresponding tool surface 35 of the first auxiliary forming tool 30 and the corresponding tool surface 25 of the first auxiliary anvil tool 20. When the clamping pressure applied to the folded area 55 is greater than or equal to the second threshold clamping pressure, the first auxiliary forming tool 30 stops moving downward. The second threshold clamping pressure can be set according to the shear modulus of the material of the sheet metal workpiece 1, and thereby determine the magnitude of the pressure that needs to be applied to the workpiece 1 in the subsequent shear deformation step of the manufacturing process. Generally, the second threshold clamping pressure is greater than or equal to 100 kPa. Optionally, the clamping pressure of the folded area 55 should not exceed the yield stress of the material forming the workpiece 1, because too large a clamping pressure may cause unnecessary thinning and tearing of parts of the workpiece. A clamping pressure exceeding the yield stress of the material forming the workpiece 1 may cause forging of the workpiece. In fact, the upper limit of the clamping pressure can be set according to the upper limit of the gas spring or hydraulic buffer applying the clamping pressure.

[0072] Then, as discussed with respect to Figure 1E , Figure 1F , Figure 2E and Figure 2F discussed, Figure 3F shows the process of sliding the first auxiliary forming tool 30 along the folded area 55, causing shear material transfer in the folded area 55 to further deform the folded area 55 and make the folded area 55 consistent with the unfolded areas of the side wall parts 51, 61. In Figure 3E and Figure 3FBetween them, it is obvious that the first auxiliary forming tool 30 and the first auxiliary anvil tool 20 slide downward simultaneously relative to the main anvil tool 10 and at the same speed, so that the material at the edge of the raised folding region 55 is discharged from the clamping portion and deformed to be consistent with the unfolded side wall portions 51, 61. At the same time, the remaining raised portions of the folding region 55 are still clamped between the two tools 20, 30. The first auxiliary forming tool 30 and the first auxiliary anvil tool 20 continue to move downward together. As more material is discharged from the clamping area, the size of the raised portion of the folding region 55 gradually decreases until the material of the folding region 55 completely passes through the forming tool, and the folding region 55 is consistent with the side wall portions 51, 61. In the sliding step, the movements of the first auxiliary forming tool 30 and the first auxiliary anvil tool 20 can be controlled independently of each other (although they move simultaneously and at the same speed), or the movement of the first auxiliary anvil tool 20 can be caused by the first auxiliary forming tool 30 transferring a sufficient amount of pressure to the first auxiliary anvil tool 20 (through the workpiece 1 clamped therebetween, or through the contact between the tools located outside the periphery of the workpiece), prompting the first auxiliary anvil tool 20 to move downward together with the forming tool 30.

[0073] Figures 4A to 4E The respective stages of the above manufacturing process for forming a formed metal sheet structure having a plurality of bends in the substrate are shown in sequence, and a plurality of folding regions will be formed correspondingly during the manufacturing process.

[0074] As in the examples discussed with respect to Figures 1A to 1F , Figures 2A to 2F , and Figures 3A to 3F , the workpiece 100 includes opposite first surface 103 and second surface 105. Here, the first surface and the second surface are respectively the lower surface (not shown) and the upper surface of the sheet. The sheet has an outer peripheral edge 107. The shape of the metal sheet workpiece 101 and the one or more outer peripheral edges 107 it has are not necessary and can be appropriately selected based on the shape of the formed metal sheet structure to be produced. At the process stage shown in Figure 4A , the workpiece 101 is planar, and a main anvil tool 110 is provided for contacting and constraining at least a part of the workpiece 101. The main anvil tool 110 has a tool surface 115. The main anvil tool 110 further includes side walls 116 extending from the tool surface 115, and in Figure 4A , the edge where the side wall 116 intersects the tool surface 115 is beveled to help the side wall portions 151, 161 deform smoothly in subsequent steps of the process.

[0075] At the stage shown in Figure 4B , the workpiece 101 has been bent to form the base region of the workpiece. Specifically, Figure 4BThe workpiece 101 therein includes a first base region 150, a second base region 160, a third base region 170, and a fourth base region 180, and there are bending portions 156, 166, 176 between adjacent base regions. In Figures 1A to 1F , Figures 2A to 2F , and Figures 3A to 3F 's example, the bending portion 156 causes the first surface 3 of the workpiece 1 to be at the bending portion 156. However, in Figure 4B , a combination of concave and convex portions of the first surface 103 is presented. Specifically: - The first bending portion 156 causes the first surface 103 of the workpiece 101 to be convex here; - The second bending portion 166 causes the first surface 103 of the workpiece 101 to be concave here; and - The third bending portion 176 causes the first surface 103 of the workpiece 101 to be concave here.

[0076] Figure 4B The workpiece 101 in Figure 1B , Figure 2B and Figure 3B also differs from the workpiece 101 in Figure 4B in that, in Figure 4B , there are first side wall portions 151, second side wall portions 161, third side wall portions 171, and fourth side wall portions 181 that all extend from the same side of the base regions 150, 160, 170, 180 to the edge 107 from their respective base regions 150, 160, 170, 180, and on the side of the base regions 150, 160, 170, 180 opposite to the first to fourth side wall portions 151, 161, 171, 181, there are also corresponding side wall portions extending from the base regions 150, 160, 170, 180. Therefore, when the manufacturing process is completed, the resulting formed metal sheet structure has a "U" - shaped cross - section, having two side walls extending from the non - planar base (see Figure 4E ). It can be understood that a more complex bending portion setting in the base of the workpiece 101 is not necessarily associated with the workpiece 101 having side wall portions extending from opposite sides of the base region to form a formed metal sheet structure with a "U" - shaped cross - section - these two features are separable.

[0077] Figure 4C shows a stage of the manufacturing process in which the step of bringing the metal sheet workpiece 101 into contact with the main anvil tool 110 and a first auxiliary forming tool (not shown) to deform the side wall portions 151, 161, 171, 181 has begun. Figure 4Cillustrates how the first sidewall portion 151, the second sidewall portion 161, the third sidewall portion 171, and the fourth sidewall portion 181 are deformed to no longer be coplanar with their respective base regions 150, 160, 170, 180. In Figure 4C , the sidewall portions 151, 161, 171, 181 are deformed downward such that the first surface 103 of the workpiece 101 is concave between the base and the sidewall (i.e., the angle between the first surface 103 in the first base region 150 and the first surface 103 in the first sidewall portion 151 is less than 180 degrees, and the same applies to other corresponding base region and sidewall portion pairs). During the process of deforming the sidewall portions 151, 161, 171, 181, a tensile region 155 corresponding to the bending portions 156, 166, 176 and two folding regions 165, 175 are formed. In Figure 4A the workpiece 101 in: - The tensile region 155 is an area where there is insufficient material in the workpiece and is prone to tearing without using this method; - The first folding region 165 is an area where there is excess material in the workpiece and is prone to buckling / wrinkling without using this method; and - The second folding region 175 is an area where there is excess material in the workpiece and is prone to buckling / wrinkling without using this method.

[0078] In Figure 4C , the deformation of the sidewall portions on the side of the base regions 150, 160, 170, 180 opposite to the first to fourth sidewall portions 151, 161, 171, 181 has also started. A second auxiliary forming tool (not shown) can be provided to contact and constrain at least a part of the second surface 105 of the metal sheet workpiece 101, and the contact of the second auxiliary forming tool with the metal sheet workpiece 101 causes these opposite sidewall portions to deform, thereby forming a tensile region and equivalent folding regions equivalent to the tensile region 155 and the second folding region 165 and the third folding region 175 visible in Figure 4C . In some embodiments of the present invention, it may be desirable for the second auxiliary forming tool to be movable relative to the main anvil tool 115 independently of the first auxiliary forming tool, for example, where the length of the sidewall portion to be deformed by the first auxiliary forming tool (i.e., the distance between the base region and the edge of the workpiece) is different from the length of the sidewall portion to be deformed by the second auxiliary forming tool. However, in other embodiments, the first auxiliary forming tool and the second auxiliary forming tool can be integrally formed, so that fewer forming tools requiring independent control are needed.

[0079] It is understood that when the bending portions 166, 176 cause the first surface 103 to be concave between adjacent substrate regions, folding regions 165, 175 are formed near these bending portions 166, 176. The folding regions 165, 175 are similar to the folding region 55 discussed above and shown in Figures 1C to 1F , Figures 2C to 2F , and Figures 3D to 3F : There is excess material in the workpiece in these folding regions, and when deforming the raised folding regions 165, 175, buckling / wrinkling is likely to occur without adopting this method. The second folding region 165 and the third folding region 175 can be further deformed in the same manner as discussed above regarding Figure 1E , 2E and 3F: The first auxiliary forming tool can slide step by step along the second folding region 165 and the third folding region 175 to cause shear material transfer therein, where the material is transferred from each folding region to one or two sidewall portions near the folding region and possibly to one or two substrate regions near the folding region. One or more additional anvil tools similar to the first auxiliary anvil tool 20 discussed regarding Figures 2A to 2F and Figures 3A to 3F can support the second folding region 165 and the third folding region 175 and assist the first auxiliary forming tool in further deforming the second folding region 165 and the third folding region 175 without causing buckling / wrinkling of the workpiece 101 in this region. Figure 4D shows a stage of this process, where the step of further deforming the second folding region 165 and the third folding region 175 is partially completed, where Figure 4C the upper portions of the raised folding regions 165, 175 present in Figure 4D have been flattened and are in alignment with the unfolded sidewall portions 161, 171, 181; the lower portions of the folding regions 165, 175 are still raised in Figure 4D and further shear material transfer is required to align the folding regions 165, 175 with the adjacent unfolded sidewall portions 161, 171, 181. Although not shown in Figure 4D , equivalent steps of the manufacturing process can be performed on the equivalent folding regions of the second folding region 165 and the third folding region 175 on the side of the substrate opposite to the second folding region 165 and the third folding region 175.

[0080] Contrary to the examples discussed in Figures 1A to 1F , Figures 2A to 2F , and Figures 3A to 3F , Figures 4A to 4EThe example in also includes a tensile region 155 formed near the first bending portion 156, wherein the first surface 103 of the sheet metal workpiece 101 is convex rather than concave. Thus, in the step of the sheet metal workpiece 101 contacting the main anvil tool 110 and the first auxiliary forming tool to deform the side wall portions 151, 161, 171, 181 relative to the base regions 150, 160, 170, the material in the tensile region 155 is prone to tearing. Region 155 is referred to as a "tensile region" because in the prior art, the material in this region needs to be greatly stretched and thinned in order to deform to conform to the side wall portion. This is because in order to transition from the undeformed side wall state shown in Figure 4B to the deformed side wall state shown in Figure 4C , the surface area of the sheet metal workpiece 101 needs to be increased near the tensile region 155.

[0081] However, in this embodiment, in the step of the manufacturing process where the first auxiliary forming tool contacts the sheet metal workpiece 101, the component can be stably deformed by in-plane shear material transfer within the deformation limit that the material can withstand before substantial thinning and tearing occur. According to the conventional flanging tool design method, appropriate tool radii can be designed for the anvil and the forming tool to enhance the stable deformation in the tensile region 155. Although not shown in Figure 4C , equivalent steps in the manufacturing process can also be performed for the equivalent tensile regions on the side of the base regions 150, 160 opposite to the tensile region 155.

[0082] Figure 4E shows a sheet metal structure 101 formed at the end of the manufacturing process, including two continuous side walls extending downward from the base, the side walls being located on opposite sides of the base, and the base being non-planar (e.g., Figure 4E having four non-coplanar base regions), but the side walls extending from the base are substantially planar (at least in the example shown in Figure 4E ). Here, the planes of the two side walls are offset from the planes of the two base regions by approximately 90°. Advantageously, compared to producing the same component via, for example, a drawing process, the formed sheet metal structure at the end of the manufacturing process shown in Figure 4E requires minimal or no trimming after forming. Additionally, the above method can not only reduce metal waste but also maintain a satisfactory sheet quality (e.g., reducing or avoiding unnecessary material deformation such as wrinkling or tearing). ***

[0083] Features disclosed in the foregoing description, or in the appended claims, or in the drawings, whether expressed in their specific form, or in the form of a device for performing the disclosed function, or a method or process for obtaining the disclosed result, may be used alone according to specific circumstances, or in any combination of said features, to implement various forms of the present invention.

[0084] Although the present invention has been described in connection with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art after obtaining the present disclosure. Therefore, the above exemplary embodiments of the present invention are considered illustrative rather than restrictive. Various changes can be made to the described embodiments without departing from the spirit and scope of the present invention.

[0085] To avoid any ambiguity, any theoretical explanations provided herein are only for helping the reader to understand. The inventors do not intend to be bound by these theoretical explanations.

[0086] Any chapter headings used herein are for purposes of arrangement only and should not be construed as limiting the subject matter described.

[0087] In this specification, including the appended claims, unless the context requires otherwise, the words "comprise" and "include", and variants such as "comprises", "comprising" and "including" shall be understood to mean including the recited integer, or step, or group of integers or steps, but not excluding any other integer, or step, or group of integers or steps.

[0088] It should be noted that, unless the context clearly dictates otherwise, the singular forms "a", "an", and "the" used in the specification and the appended claims include plural referents. Ranges may be expressed herein as from "about" one particular value and / or to "about" another particular value. When expressing such a range, another embodiment includes from one particular value and / or to another particular value. Similarly, when values are expressed in an approximate form, by using the preposition "about", it should be understood that the particular value constitutes another embodiment. The word "about" associated with a numerical value is optional, for example, representing + / - 10%. References

[0089] One or more documents are cited above in order to more fully describe and disclose the present invention and the prior art to which the present invention pertains. Complete citations of these references are provided below. The entire contents of these references are incorporated herein by reference.

[0090] Horton, P.M. and Alwood, J.M. (2017): "Timing of Yield Improvement in Manufacturing Automotive Sheet Metal Components", Journal of Materials Processing Technology, 249, 78 - 88. Reference Numerals 1, 101 Sheet Metal Workpiece 3, 103 First Surface 5, 105 Second Surface 7, 107 Outer Periphery 10, 110 Main Anvil Tool 15, 115 Tool Surface of the Main Anvil Tool 16 Side Wall of the Main Anvil Tool 20 First Auxiliary Anvil Tool 25 Tool Surface of the First Auxiliary Anvil Tool 30 First Auxiliary Forming Tool 35 Tool Surface of the First Auxiliary Forming Tool 40 Main Forming Tool 45 Tool Surface of the Main Forming Tool 50, 150 First Base Region 51, 151 First Side Wall Portion 55, 165 First Folding Region 56, 156 First Bend 60, 160 Second Base Region 61, 161 Second Side Wall Portion 155 Stretching Region 166 Second Bend 170 Third Base Region 171 Third Side Wall Portion 175 Second Folding Region 176 Third Bend 180 Fourth Base Region 181 Fourth Side Wall Portion

Claims

1. A method of manufacturing a formed metal sheet structure, comprising the steps of: providing a metal sheet workpiece having opposite first and second surfaces and at least one edge; providing a main anvil tool having a tool surface for contacting and constraining at least a portion of the first surface of the metal sheet workpiece; bending the workpiece to form at least a first base region and a second base region, with a bend therebetween, and constraining at least a portion of the base regions between the main anvil tool and a main forming tool such that the base regions are fixed relative to the main anvil tool, a first sidewall portion extending between the first base region and the edge, and a second sidewall portion extending between the second base region and the edge; providing a first auxiliary forming tool having a tool surface for contacting and constraining at least a portion of the second surface of the metal sheet workpiece; bringing the metal sheet workpiece into contact with the first auxiliary forming tool such that the first sidewall portion and the second sidewall portion are deformed relative to the first base region and the second base region, thereby forming a first folded region in the metal sheet workpiece between the first sidewall portion and the second sidewall portion; and gradually sliding the first auxiliary forming tool along the first folded region to cause shear material transfer in the first folded region, thereby further deforming the first folded region.

2. The method according to claim 1, wherein: the method further comprises the step of providing a first auxiliary anvil tool having a tool surface for contacting and constraining at least a portion of the first surface of the metal sheet workpiece at the first folded region.

3. The method according to claim 2, wherein: the method further comprises the step of gradually sliding the first auxiliary anvil tool along the first folded region; and wherein the step of gradually sliding the first auxiliary anvil tool along the first folded region is performed simultaneously with the step of sliding the first auxiliary forming tool along the first folded region to control the deformation of the first folded region.

4. The method according to claim 3, wherein The step of gradually sliding the first auxiliary anvil tool along the first folded region is achieved by the step of gradually sliding the first auxiliary forming tool along the first folded region.

5. The method according to any one of claims 2 to 4, wherein The main anvil tool and the first auxiliary anvil tool are respectively connected to a first pressure plate, and at least one of the main anvil tool and the first auxiliary anvil tool is movably connected to the first pressure plate.

6. The method according to any one of claims 1 to 5, wherein: the main anvil tool includes a sidewall; in the step of bringing the metal sheet workpiece into contact with the first auxiliary forming tool, the sidewall of the main anvil tool constrains at least a portion of the first surface of the first sidewall portion of the workpiece and at least a portion of the first surface of the second sidewall portion of the workpiece; and In the step of sliding the first auxiliary forming tool along the first folding area, the side wall of the main anvil tool constrains at least a part of the first surface of the first folding area.

7. The method according to any one of claims 1 to 6, wherein, The step of bending the workpiece to form the first base area and the second base area is performed by clamping the sheet metal workpiece between the corresponding tool surfaces of the main anvil tool and the main forming tool.

8. The method according to any one of claims 1 to 7, wherein The main forming tool and the first auxiliary forming tool are respectively connected to a second pressure plate, and at least one of the main forming tool and the first auxiliary forming tool is movably connected to the second pressure plate.

9. The method according to any one of claims 1 to 8, wherein: The method further comprises the step of: bending the workpiece to form a third base area, having a second bend between the second base area and the third base area, and a third side wall portion extending between the third base area and the edge; The step of bringing the sheet metal workpiece into contact with the first auxiliary forming tool also deforms the third side wall portion relative to the third base area, thereby forming a second folding area in the sheet metal workpiece between the second side wall portion and the third side wall portion; and The method further comprises the step of: gradually sliding the first auxiliary forming tool along the second folding area to further deform the second folding area.

10. The method according to any one of claims 1 to 9, wherein: The first side wall portion and the second side wall portion are provided on a first side of the base area; A fourth side wall portion extends between the first base area and the edge of the sheet metal workpiece on the other side of the base area, and a fifth side wall portion extends between the second base area and the edge; And The method further comprises the step of: providing a second auxiliary forming tool having a tool surface for contacting and constraining at least a part of the second surface of the sheet metal workpiece; bringing the sheet metal workpiece into contact with the second auxiliary forming tool to deform the fourth side wall portion and the fifth side wall portion relative to the first base area and the second base area, thereby forming a third folding area in the sheet metal workpiece between the fourth side wall portion and the fifth side wall portion; and gradually sliding the second auxiliary forming tool along the third folding area to cause shear material transfer in the third folding area, thereby further deforming the third folding area.

11. The method according to claim 10, wherein, The second auxiliary forming tool is integrally formed with the first auxiliary forming tool.

12. A metal sheet processing device for manufacturing a formed metal sheet structure from a metal sheet workpiece, the metal sheet workpiece having opposite first and second surfaces and at least one edge, the formed metal sheet structure having at least a first base region and a second base region, there being a bend between the first base region and the second base region, a first side wall portion extending between the first base region and the edge, a second side wall portion extending between the second base region and the edge, the metal sheet processing device comprising: A main anvil tool having a tool surface for contacting and constraining at least a portion of the first surface of the metal sheet workpiece; A main forming tool, the main forming tool and the main anvil tool being for constraining at least a portion of the base region; A first auxiliary forming tool having a tool surface for contacting and constraining at least a portion of the second surface of the metal sheet workpiece; Wherein the first auxiliary forming tool is configured to: Contact the metal sheet workpiece to deform the first side wall portion and the second side wall portion relative to the first base region and the second base region, thereby forming a first folded region in the metal sheet workpiece between the first side wall portion and the second side wall portion; And Slide along the first folded region to cause shear material transfer in the first folded region, thereby further deforming the first folded region.

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