Sheet metal processing

Abstract

A formed sheet metal structure is produced from a sheet metal workpiece (1, 101). A primary anvil tool (10, 110) restrains a first surface (3, 103) of the sheet metal workpiece. The workpiece is bent to form a first base region (50, 150) and a second base region (60, 160) with a bend (56, 156) therebetween. A first auxiliary forming tool (30) deforms first and second sidewall portions (51, 61, 151, 161) relative to the first and second base regions (50, 60, 150, 160), thereby forming a first bend region (55, 165) in the sheet metal workpiece (1, 101) between the first sidewall portion (51, 151) and the second sidewall portion (61, 161). By gradually sliding the first auxiliary forming tool (30) along the first folding region (55, 165), shear material movement occurs in the first folding region (55, 165) and further deforms the first folding region (55, 165).

Description

[Technical Field]

[0001] The present invention relates to a sheet metal processing method and a sheet metal structure obtainable by said sheet metal processing method.The present invention also relates to a sheet metal processing device. [Background technology]

[0002] Half of the sheet metal produced worldwide each year is not used in the final product but is cut off during manufacturing. The two main sources of this loss are blanking (cutting flat shapes from the coiled long sheets produced by the rolling mill) and trimming after deep drawing, with the latter accounting for the majority of the loss. Such losses are an unavoidable by-product of these processes. Further discussion and quantification of these losses is provided in Horton and Allwood (2017).

[0003] Currently, the process of blanking followed by deep drawing is considered the most efficient way to manufacture formed sheet metal parts, such as car body parts, but the costs, both monetary and carbon dioxide emissions, associated with these losses are high. In blanking and deep drawing, avoiding wrinkling and tearing during forming is an important consideration.

[0004] WO 2020 / 043832 discloses a folding shear process that can form metal shells from sheet metal with minimal thinning or unwanted deformation, with curved sidewalls rising from a base region where shrink flanges and stretch flanges are formed. In the process of forming stretch flanges, the material at the bends must be stretched, but this must be done in a way that limits thinning of the sheet at the bends and edge cracking. In the process of forming shrink flanges, the material at the bends must be compressed, but this must be done in a way that limits thickness and buckling / wrinkling of the sheet at the bends. In WO 2020 / 043832, this is achieved by shear material movement during the process.

[0005] In WO 2020 / 043832, the base of the shell from which the side walls rise is flat, so only when there are curved side walls rising from the base do shrinkage and stretch flanges form and need to be sheared. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 043832 [Non-patent literature]

[0007] [Non-Patent Document 1] Horton, PM and Allwood, JM (2017): “Yield improvement opportunities for manufacturing automotive sheet metal components”, Journal of Materials Processing Technology, 249 78-88 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the inventors have recognized that it is also desirable to form metal shells having non-planar bases. A difficulty in forming such metal shells is that even in the absence of curved sidewalls, i.e., shrinkage flanges or stretch flanges as referred to in WO 2020 / 043832, the act of bending the sidewalls to rise from the non-planar base creates potential shrinkage and stretch zones in adjacent regions of the sidewall that extend from adjacent base regions that are not coplanar. The shrinkage and stretch zones in the sidewall are prone to buckling / wrinkling and tearing, respectively, when using known sheet metal processing equipment.

[0009] The present invention has been made in view of the above points. [Means for solving the problem]

[0010] In a first aspect, a method for manufacturing a formed sheet metal structure is provided, the method including the steps of providing a sheet metal workpiece having opposing 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 sheet metal workpiece; bending the workpiece to form at least a first base region and a second base region having a bend therebetween, and constraining at least a portion of the base regions between the main anvil tool and the main forming tool so that the base regions are fixed relative to the main anvil tool and have a first sidewall extending between the first base region and the edge and a second sidewall extending between the second base region and the edge. providing a first auxiliary forming tool having a tool surface for contacting and restraining at least a portion of the second surface of the sheet metal workpiece; contacting the sheet metal workpiece with the first auxiliary forming tool to deform the first and second sidewall portions relative to the first and second base regions, thereby forming a first bend region in the sheet metal workpiece between the first and second sidewall portions; and incrementally sliding the first auxiliary forming tool along the first bend region to cause displacement of shear material in the first bend region to further deform the first bend region.

[0011] The method of manufacturing a shaped sheet metal structure according to the first aspect allows for forming sidewalls extending from a non-planar base in the sheet metal structure with reduced risk of buckling, wrinkling, or tearing of the material in the bend region of the sidewall. The bend region may be formed adjacent to a bend formed such that the first surface of the workpiece is concave at the first bend. The steps of the method according to the first aspect may be performed in the order listed above.

[0012] The method can further include 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 in the first bending region. By providing the first auxiliary anvil tool, greater control of shear transfer of material from the bending region can be achieved during the step of progressively sliding the first auxiliary forming tool along the first bending region. Constraining the first surface of the workpiece in the first bending region with the first auxiliary anvil tool also reduces the likelihood of buckling / wrinkling in the bending region.

[0013] The step of contacting the sheet metal workpiece with the main anvil tool and the first auxiliary forming tool can be performed so that a clamping pressure of 100 kPa or more is applied to the portion of the sheet metal workpiece between the 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 is beneficial for promoting the movement of sheared material during the step of sliding the first auxiliary forming tool along the first bending region. The clamping pressure can be appropriately adjusted depending on the material and thickness of the workpiece.

[0014] The method can further include progressively sliding the first auxiliary anvil tool along the first folding region. In such cases, the progressively sliding the first auxiliary anvil tool along the first folding region can be performed simultaneously with the sliding of the first auxiliary forming tool along the first folding region to control deformation of the first folding region. Advantageously, sliding the first auxiliary anvil tool along the first folding region simultaneously with the first auxiliary forming tool promotes shear material transfer from the folding region and reduces the likelihood of buckling / wrinkling in the folding region. In effect, the first auxiliary anvil tool provides a movement constraint together with the first auxiliary forming tool, constraining the workpiece material in the folding region and reducing buckling / wrinkling. As will be appreciated, it is contemplated 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.

[0015] The gradual sliding of the first auxiliary anvil tool along the first folding region can be effected by gradual sliding of the first auxiliary forming tool along the first folding region, which provides a simple way of ensuring that the first auxiliary forming tool and the first auxiliary anvil tool move in cooperation, for example at the same speed (same velocity and direction), enhancing shear material transfer of material from the folding region and reducing the likelihood of buckling / wrinkling in the folding region.

[0016] The main anvil tool and the first auxiliary anvil tool may each be connected to the first press plate. In such a case, at least one of the main anvil tool and the first auxiliary anvil tool may be movably connected to the first press plate. Advantageously, this configuration allows the main anvil tool and the first auxiliary anvil tool to move together as if they were a single tool, or to move independently of each other.

[0017] The main anvil tool may include a sidewall. In such a case, the sidewall of the main anvil tool may restrain at least a portion of a first surface of the first sidewall portion of the workpiece and at least a portion of a first surface of the second sidewall portion of the workpiece during the step of contacting the sheet metal workpiece with the first auxiliary forming tool. Furthermore, the sidewall of the main anvil tool may restrain at least a portion of a first surface of the first folding region during the step of sliding the first auxiliary forming tool along the first folding region. Thus, the sidewall of the main anvil tool acts to restrain deformation of the workpiece and may reduce the possibility of tearing and / or buckling of the workpiece during deformation of the workpiece. The sidewall of the main anvil tool may be substantially planar.

[0018] Bending the workpiece to form the first and second base regions can be performed by clamping the sheet metal workpiece between the tool surfaces of the primary anvil tool and the primary forming tool. Performing the bending in this manner is beneficial in that the bends formed in the workpiece precisely conform to the shape of the tool surfaces of the primary anvil tool and the primary forming tool.

[0019] The step of clamping the sheet metal workpiece between the primary anvil tool and the primary forming tool can be performed such that a clamping pressure of 100 kPa or more is exerted on the portion of the sheet metal workpiece between the tool surfaces of the primary anvil tool and the primary forming tool. Advantageously, applying sufficient pressure to the portion of the workpiece clamped between the primary anvil tool and the primary forming tool promotes plastic deformation of the workpiece during the bending process. The clamping pressure can be set to balance the elastic recovery of the workpiece against the thinning of the workpiece caused by clamping and subsequent deformation.

[0020] The sheet metal workpiece may remain clamped between the main anvil tool and the main forming tool during the following steps: contacting the sheet metal workpiece with the main anvil tool and the first auxiliary forming tool to deform the first and second sidewall portions; and progressively 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 movement of the base region during subsequent deformation steps.

[0021] The main forming tool and the first auxiliary forming tool may each be connected to a second press plate, and at least one of the main forming tool and the first auxiliary forming tool may be movably connected to the second press plate. Advantageously, this arrangement allows the main forming tool and the first auxiliary forming tool to move together as if they were a single tool, or to move independently of each other.

[0022] The method can further include bending the workpiece to form a third base region having a second bend between the second base region and the third base region, after which there is a third sidewall portion extending between the third base region and the edge. Next, contacting the sheet metal workpiece with the first auxiliary forming tool can also deform the third sidewall portion relative to the third base region to form a second bend region in the sheet metal workpiece between the second sidewall portion and the third sidewall portion. Next, the method can further include incrementally sliding the first auxiliary forming tool along the second bend region to further deform the second bend region.

[0023] The first and second sidewall portions may be provided on a first side of the base region. Then, a fourth sidewall portion may extend between the first base region and an edge of the sheet metal workpiece on another side of the base region, and a fifth sidewall portion may extend between the second base region and the edge. In such a case, the method may further include the steps of: providing a second auxiliary forming tool having a tool surface for contacting and restraining at least a portion of a second surface of the sheet metal workpiece; contacting the sheet metal workpiece with the second auxiliary forming tool to deform the fourth and fifth sidewall portions relative to the first and second base regions, thereby forming a third bend region in the sheet metal workpiece between the fourth and fifth sidewall portions; and incrementally sliding the second auxiliary forming tool along the third bend region to displace shear material in the third bend region and further deform the third bend region. Advantageously, this allows angular or channel shaped sheet metal structures to be formed using the method.

[0024] The second auxiliary forming tool can be integrally formed with the first auxiliary forming tool, thus reducing the number of forming tools that require independent control during the method and allowing for more accurate tool deformation since the distance between the forming tools is more tightly constrained by the forming tools being integrally formed with one another.

[0025] In a second aspect, there is provided a workpiece obtained or obtainable using a method according to the first aspect.

[0026] In a third aspect, there is provided a sheet metal processing apparatus suitable for carrying out the method for manufacturing a shaped sheet metal structure according to the first aspect.

[0027] In a fourth aspect, a sheet metal processing apparatus is provided for producing a shaped sheet metal structure from a sheet metal workpiece. The sheet metal workpiece has opposing first and second surfaces and at least one edge. The shaped sheet metal structure to be produced has at least a first base region and a second base region with a bend therebetween, 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 processing apparatus includes a primary anvil tool having a tool surface for contacting and constraining at least a portion of the first surface of the sheet metal workpiece, a primary forming tool configured to constrain at least a portion of the base region together with the primary anvil tool, and 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 configured to contact the sheet metal workpiece to deform the first and second sidewall portions relative to the first and second base regions, thereby forming a first bend region in the sheet metal workpiece between the first and second sidewall portions, and is further configured to slide along the first bend region to displace shear material in the first bend region and further deform the first bend region.

[0028] The above method (referred to herein as the "fold-shear" method) can enable the production of formed sheet metal structures that require minimal or no post-forming trimming compared to producing the same part using a deep drawing process. Additionally, the above method can enable the reduction of metal scrap while maintaining satisfactory sheet quality (e.g., reducing or avoiding undesirable material deformations such as wrinkles or tears).

[0029] The exact shape of the curved base and one or more sidewalls extending therefrom is not particularly limited and can take many different forms depending on the particular molding process and the desired final shape of the product. In some embodiments, the one or more sidewalls can be substantially planar, while in other embodiments, both the base and the sidewalls can be curved. In some embodiments, the one or more sidewalls extend generally perpendicular from the base, while in other embodiments, the one or more sidewalls can be at a different angle relative to the base.

[0030] Here, the term "base region" is used to define a planar, base-like region of a sheet metal workpiece. The base region may experience little or no bending and / or deformation during the forming process. In other words, the base region may be a region of the workpiece that does not change from its original size and shape during the forming operation. In other forming processes, the base region may also experience shear deformation. The size and shape of the base region are not particularly limited and can be selected appropriately taking into account the intended shape of the formed sheet metal structure.

[0031] The exact nature of further deformation of the fold region during the step of gradually sliding the forming tool along the fold region is not particularly limited and depends on the particular forming process and the desired final shape of the product. Shear material movement in the fold region can occur via material movement from the fold region to at least one sidewall portion and / or material movement from at least one sidewall portion to the fold region. However, in some embodiments, shear material movement in the fold region can also or instead occur via shear material movement to or from a base region of the sheet.

[0032] Material transfer from the bend region to at least one sidewall portion can improve sidewall formation when the first surface of the sheet metal is recessed between adjacent base regions. Enabling such material transfer may enable the production of formed sheet metal structures having non-planar bases of various shapes with little or no thinning or thickening of sidewall material, thereby helping to reduce the occurrence of wrinkling and / or tearing during the forming process.

[0033] The anvil tool and / or the forming tool can have a rounded tool surface. The rounded tool surface of the anvil tool may be complementary to that of the forming tool. For example, the curvature of the rounded tool surface of the anvil tool may be opposite to the curvature of the rounded tool surface of the forming tool.

[0034] As used herein, the terms "sidewall" and "sidewall portion" are generally used with respect to a workpiece to define a portion of the workpiece that forms a sidewall relative to a base region of the sheet metal. In other words, a portion of the sheet that is inclined relative to the base region of the sheet to form a sidewall, or that is intended to be inclined during the manufacturing process, relative to the base region of the sheet. The bending / folding performed to form such a sidewall portion may be partially elastic or fully plastic. In some cases, a fold may be formed along a fold line adjacent to the base region of the sheet. Such a fold line may define an edge of the base region. The number of sidewall portions can be appropriately selected taking into account the desired final shape of the formed sheet metal structure. As described above, there may be at least a first sidewall portion and a second sidewall portion. Preferably, each sidewall portion extends from the base region (e.g., from a fold line defining the edge of the base region) to the edge of the sheet metal workpiece.

[0035] The term "curved" is considered synonymous with "rounded" and is generally used to refer to a region having some degree of curvature. The curvature may vary from region to region. Thus, the terms curved or rounded are not used herein to refer exclusively to regions having a constant curvature (i.e., they are not intended to be limited to only cylindrical or spherical regions).

[0036] Preferably, the sheet metal working equipment can be retrofitted to existing press lines, for example the bending step can be performed with existing tooling currently used in some deep drawing processes.

[0037] Preferably, the main anvil tool and the first auxiliary anvil tool, and the main forming tool and the first auxiliary forming tool are replaceable with additional anvil tools and additional forming tools, respectively.

[0038] In a fifth preferred aspect, the present invention provides a kit comprising the sheet metal working apparatus of the third or fourth aspect, one or more further anvil tools, and one or more further forming tools.

[0039] The present invention includes the described embodiments and any combination of features except where such combination is expressly not permitted or explicitly avoided.

[0040] Examples illustrating the principles of the present invention will now be described with reference to the accompanying drawings. [Brief explanation of the drawings]

[0041] [Figure 1A] 1A-1C illustrate successive process steps in a method for manufacturing a formed sheet metal structure having a non-planar base and sidewalls extending therefrom. [Figure 1B] 1A-1C illustrate successive process steps in a method for manufacturing a formed sheet metal structure having a non-planar base and sidewalls extending therefrom. [Figure 1C] 1A-1C illustrate successive process steps in a method for manufacturing a formed sheet metal structure having a non-planar base and sidewalls extending therefrom. [Figure 1D] 1A-1C illustrate successive process steps in a method for manufacturing a formed sheet metal structure having a non-planar base and sidewalls extending therefrom. [Figure 1E] 1A-1C illustrate successive process steps in a method for manufacturing a formed sheet metal structure having a non-planar base and sidewalls extending therefrom. [Figure 1F] 1A-1C illustrate successive process steps in a method for manufacturing a formed sheet metal structure having a non-planar base and sidewalls extending therefrom. [Figure 2A] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 2B] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 2C] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 2D] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 2E] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 2F] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 3A] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and sheet metal processing equipment used in the method. [Figure 3B] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and sheet metal processing equipment used in the method. [Figure 3C] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and sheet metal processing equipment used in the method. [Figure 3D] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and sheet metal processing equipment used in the method. [Figure 3E] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and sheet metal processing equipment used in the method. [Figure 3F] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and sheet metal processing equipment used in the method. [Figure 4A] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 4B] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 4C] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 4D] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 4E] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. [Figure 4F] 1 illustrates successive process steps in a method for manufacturing a shaped sheet metal structure having a non-planar base and sidewalls extending therefrom, and a portion of a sheet metal processing apparatus used in the method. DETAILED DESCRIPTION OF THE INVENTION

[0042] Aspects and embodiments of the present invention will now be described with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned herein are incorporated by reference.

[0043] The process described herein can be understood as "folding-shearing" and can be used to transform sheet metal blanks into shell shapes (such as cans, boxes, and car body parts) that are currently produced by deep drawing, reducing the need for post-forming trimming.

[0044] This process will now be described with reference to Figures 1 to 4. Each figure includes several partial views showing the shape of the sheet metal structure, and in some cases the shape and position of the sheet metal processing equipment, at different stages in the process of producing a "fold-shear" formed sheet metal structure.

[0045] 1A to 1F show the shape of a sheet metal structure 1 at successive stages in the "folding-shearing" process specified in the present application, in the order from FIG. 1A to FIG. 1F.

[0046] The process begins with an initially flat metal sheet, as shown in FIG. 1A, and the final formed sheet metal structure has planar sidewalls that descend at approximately 90° from the non-planar base of the workpiece, as shown in FIG. 1F.

[0047] The first stage of the manufacturing process involves providing a flat sheet metal workpiece 1, as shown in FIG. 1A. The sheet metal workpiece has a first surface 3 and a second surface 5 opposite each other, where the first and second surfaces are the bottom surface (not visible) and top surface of the sheet metal, respectively. The sheet metal has a peripheral edge 7. The shape of the sheet metal workpiece 1 and the one or more peripheral edges 7 it has are not required and can be selected based on the shape of the formed sheet metal structure desired to be manufactured. The sheet metal workpiece 1 is placed in a sheet metal processing apparatus (not shown in FIGS. 1A-1F).

[0048] FIG. 1B illustrates bending workpiece 1 to form first and second base regions 50 and 60, which together form the base of workpiece 1. First and second base regions 50 and 60 are individually generally planar but are separated by a bend 56 located therebetween. In FIG. 1B, workpiece 1 is bent such that first surface 3 of workpiece 1 is recessed between first and second base regions 50 and 60, i.e., the angle between base regions 50, 60 perpendicular to first surface 3 is less than 180°. A first sidewall portion 51 extends from first base region 50 to periphery 7 of workpiece 1. Similarly, a second sidewall portion 61 extends from second base region 60, and this sidewall portion 61 also extends to periphery 7 of workpiece 1. At the stage shown in FIG. 1B, the first sidewall portion 51 and the second sidewall portion 61 remain flush with their respective base regions 50, 60, but are not flush with each other because they were bent as part of the process of forming the first base region 50 and the second base region 60.

[0049] 1C , the first and second sidewall portions 51, 61 are deformed relative to the first and second base regions 50, 60 such that they are no longer coplanar with the respective base regions 50, 60. In FIG. 1C , the sidewall portions 51, 61 are deformed downward such that the first surface 3 of the workpiece 1 is recessed between the base and the sidewall portions (i.e., the angle between the first surface 3 of the first base region 50 and the first surface 3 of the first sidewall portion 51 is less than 180°, and the angle between the first surface 3 of the second base region and the first surface 3 of the second sidewall portion 61 is less than 180°). Sidewall bends 57 are formed between the base regions 50, 60 and the corresponding sidewall portions. The process of deforming the first and second sidewall portions 51, 61 forms fold regions 55 that generally correspond to bends 56. 1A-1F, bend 56 is recessed relative to first surface 3, so fold region 55 is where excess material exists within the workpiece when sidewall portions 51, 61 deform. fold region 55 in FIGS. 1C-1F is where buckling / wrinkling would occur without the present methodology.

[0050] FIG. 1D illustrates a stage in the process where a substantial portion of each sidewall portion 51, 61 has deformed to form a desired angle relative to the base region 50, 60, approximately 90° as measured from the first surface 3 of the workpiece 1. These regions of the sidewall portions 51, 61 may be referred to as "developable regions." However, the fold region 55 incorporating the non-developable regions of the sidewall portions 51, 61 forms a raised, undeveloped "beak" shape due to the change in surface area required to transition from the undeformed sidewall state shown in FIG. 1B to the deformed sidewall state shown in FIG. 1F. For the workpiece at the stage illustrated in FIG. 1D, the fold region 55 is formed such that the metal within the fold region 55 has undergone minimal stretching and / or compression. Deforming the sidewall portions 51, 61 to the stage illustrated in FIG. 1D results in no or only a minimal change in the thickness of the workpiece 1, e.g., a change of no more than about ±10%. To provide the final formed metal sheet structure shown in FIG. 1F, further deformation of the folding region 55 is required to remove the raised portions of the folding region 55 and conform the folding region 55 to the deformed sidewall portions 51, 61, but such further deformation is likely to cause buckling / wrinkling of the sheet metal workpiece 1 at the folding region 55 due to the reduced surface area required there.

[0051] Later in the manufacturing process, a forming tool (not shown) is progressively slid along the fold region 55, causing shear material movement therein and permitting further deformation of the fold region 55 without buckling / wrinkling the workpiece 1 in this region. FIG. 1E shows this process partially completed. The raised top of the fold region 55 present in FIG. 1D has flattened in FIG. 1E, forming a wrinkle-free sidewall due to shear material movement in the fold region, with material movement from the fold region to at least one sidewall portion. The lower portion of the fold region 55 is still raised in FIG. 1E, requiring further shear material movement for the fold region 55 to conform to the unfolded sidewall portions 51, 61.

[0052] The resulting sheet metal structure at the end of the manufacturing process is shown in FIG. 1F and includes a continuous sidewall extending downward from a base that is non-planar (i.e., has two base regions that are not coplanar with one another), but whose sidewalls extending from the base are substantially planar across sidewall portions 51, 61 (at least in the example shown in FIG. 1F). While the sidewalls in FIG. 1F are substantially planar across sidewall portions 51, 61, sidewalls formed according to this process may be non-planar across sidewall portions 51, 61. However, the greater the deviation of the sidewall portions from planarity, the greater the amount of workpiece stretching or shrinkage that the process must accommodate. Here, the sidewalls lie in a plane that is approximately 90° offset from the plane of both base regions. Advantageously, the resulting sheet metal structure at the end of the manufacturing process, as shown in FIG. 1F, requires minimal or no trimming after forming, compared to, for example, producing the same part using a deep drawing process. Additionally, the above methods can allow for a reduction in metal debris while maintaining satisfactory sheet quality (e.g., reducing or avoiding undesirable material deformations such as wrinkling or tearing).

[0053] 2A-2F, in order from FIG. 2A to FIG. 2F, illustrate the shape of a sheet metal workpiece 1 at successive stages in the "fold-shear" process of the present invention, and its interaction with some of the sheet metal working equipment that can be used in the process. In particular, features of the workpiece, as well as the main anvil tool and the first auxiliary anvil tool, are shown.

[0054] The shape of each sheet metal structure 1 in Figures 2A to 2F is the same as the shape of each sheet metal structure 1 in Figures 1A to 1F, respectively. Therefore, detailed description of the shape of the sheet metal structure 1 in each of Figures 2A to 2F will be omitted.

[0055] In FIG. 2A , a primary anvil tool 10 for use in forming a sheet metal structure is provided. The primary anvil tool 10 has a tool surface 15 (partially obscured in FIG. 2A by the sheet metal workpiece 1) that contacts and restrains at least a portion of the first (lower) surface 3 of the sheet metal workpiece 1. The tool surface 15 of the primary anvil tool 10 is the upper surface of the anvil tool 10 in FIG. 2A . The primary anvil tool 10 further includes a sidewall 16 extending from the tool surface 15, and in FIG. 2A , the edges where the sidewall 16 and the tool surface 15 meet are chamfered to aid in smooth deformation of the sidewall portions 51, 61 later in the process. Also shown in FIG. 2A is a first auxiliary anvil tool 20, which also has a tool surface 25 for contacting and restraining at least a portion of the first (lower) surface 3 of the sheet metal workpiece 1. The manufacturing process can utilize a first auxiliary anvil tool 20 to provide greater control over the shaping of the sheet metal workpiece 1, as described below in connection with Figures 2D-2F, although the process can also be performed without the first auxiliary anvil tool 20.

[0056] When present, the main anvil tool 10 and the first auxiliary anvil tool 20 can both be connected to a first press plate for attachment to a metal forming press. As described below in connection with FIG. 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 press plate, at least one of the anvil tools 10, 20 is movably connected to the first press plate. The movably connection between the anvil tool and the first press plate can be via, for example, a hydraulically or mechanically actuated ram.

[0057] In Figure 2B, the sheet metal workpiece 1 has been bent to form first and second base regions 50, 60, as described above in connection with Figure 1B. Figure 2B shows how the workpiece 1 is bent to form the first and second base regions 50, 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 and second base regions 50, 60 conform to 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 provided adjacent the side wall 16 of the main anvil tool 10 and is optionally truncated, taking the general shape of an oblique triangular pyramid with its apex laterally aligned with the bend 56.

[0058] 2C , the first and second sidewall portions 51, 61 are deformed relative to the first and second base regions 50, 60 such that they are no longer coplanar with their respective base regions 50, 60. A sidewall bend 57 is formed between the tool surface 15 and the sidewall 16 of the main anvil tool, coinciding with the chamfered edge. The first and second sidewall portions 51, 61 are deformed about the edge between the tool surface 15 and the sidewall 16 of the main anvil tool 10 such that the deployable area of ​​the sidewall portions 51, 61 of the sheet metal workpiece 1 approaches the sidewall 16 of the main anvil tool 10. A fold region 55 corresponding to the bend 56 is formed by excess material present in the workpiece at this location as the sidewall portions 51, 61 are deformed. This deformation continues until the stage shown in FIG. 2D is reached, at which point the deployable regions of the sidewall portions 51, 61 deform and the first surfaces 3 of these regions contact and are constrained by the sidewalls 16 of the main anvil tool 10. In the case of the main anvil tool 10 shown in FIG. 2D, the sidewalls 16 are generally perpendicular to the tool surface 15, so that the deployable regions of the sidewall portions 51, 61 at the stage shown in FIG. 2D are generally perpendicular to the base regions 50, 60. However, the angle of the sidewalls 16 relative to the tool surface 15 is not particularly limited and can be set to provide any desired angle between the base and the sidewalls in the formed sheet metal structure. Deformation of the sidewall portions 51, 61 is achieved by contacting the main anvil tool 10 and a first auxiliary forming tool (not shown) with the sheet metal workpiece.

[0059] 2D also shows that at least a portion of the first surface 3 of the sheet metal workpiece 1 contacts and is restrained by the tool surface 25 of the first auxiliary anvil tool 20 in the folding region 55. The folding region 55 is supported by the first auxiliary anvil tool 20 so as to prevent the sheet metal workpiece 1 from undergoing deformation that would cause buckling / wrinkling in the folding region 55 while deforming the sidewall portions 51, 61. Typically, the first auxiliary anvil tool 20 prevents buckling in the bending region 55 by providing a tool surface 25 that restrains the bending region 55 so that stretching and / or compression of the material in the bending region 55 is minimized during deformation of the side wall portions 51, 61 and so that the thickness of the sheet metal workpiece 1 does not change substantially while deforming the expandable regions of the side wall portions 51, 61 (i.e., the thickness of the sheet metal workpiece 1 does not change, or changes only minimally, e.g., by no more than about ±10%, from the stage shown in FIG. 2B to the stage shown in FIG. 2D ).

[0060] 2E next shows a portion of workpiece 1 at a later stage in the manufacturing process in which a first auxiliary forming tool (not shown) is progressively slid along folding region 55, causing shear material movement therein to conform folding region 55 with the unfolded regions of sidewall portions 51, 61. To conform folding region 55 to the unfolded sidewall portions 51, 61, e.g., to make folding region 55 flush with the unfolded regions of sidewall portions 51, 61 as in FIG. 2F, shear material movement is required to move material from folding region 55 to at least one, and potentially both, sidewall portions 51, 61 and / or one or both base regions 50, 60 adjacent folding region 55 without buckling / wrinkling the material in folding region 55. 2D, the folding region 55 is constrained by the tool surface 25 of the first auxiliary anvil tool 20, preventing the folding region 55 from conforming to the adjacent sidewall portions 51, 61. In order to deform the folding region 55, the first auxiliary anvil tool 20 must be withdrawn from under the folding region 55 so that it no longer constrains the entire folding region 55.

[0061] To allow for controlled deformation of the folding region 55, the first auxiliary anvil tool 20 is withdrawn from beneath the folding region 55 simultaneously with a first auxiliary forming tool (not shown) sliding along the folding region 55, allowing only the small portion of the folding region 55 not constrained by the first auxiliary anvil tool 20 to be deformed by the first auxiliary forming tool at any given time. The portion of the folding region 55 not constrained by the first auxiliary anvil tool 20 is conformed to the adjacent unfolded region of the sidewall portions 51, 61 by shear material transfer from the folding region 55 to the sidewall portions 51, 61 (and potentially the adjacent base regions 50, 60). In FIG. 2E, this controlled deformation of the folding region 55 is partially complete, with the top of the raised folding region 55 present in FIG. 2D flattening in FIG. 2E to conform to the unfolded sidewall portions 51, 61 without buckling / wrinkling. In FIG. 2E, the first auxiliary anvil tool 20 is lower relative to the main anvil tool 10 and workpiece 1 than in FIG. 2D.

[0062] This sliding process continues, gradually reducing the raised portion of the bend region 55, until the material in the bend region 55 is completely pulled through the forming tool, achieving the shape of the formed sheet metal structure shown in FIG. 2F. The formed sheet metal structure of FIG. 2F consists of a continuous sidewall extending downward from a base, which is non-planar (i.e., has two base regions that are not coplanar with each other), but whose sidewalls extending from the base are substantially planar (as in the example shown in FIG. 2F). Here, the sidewalls lie in a plane offset by approximately 90° from the plane of both base regions. Advantageously, as shown in FIG. 2F, the formed sheet metal structure at the end of the manufacturing process requires minimal or no trimming after forming, compared to, for example, producing the same part using a deep drawing process. Furthermore, the above method can reduce metal waste while maintaining satisfactory sheet quality (e.g., reducing or avoiding undesirable material deformations such as wrinkles or tears).

[0063] 3A-3F show, in order from FIG. 3A to FIG. 3F, the shape of the sheet metal structure 1 at successive stages in the "fold-shear" process of the present invention, and the interaction of the sheet metal workpiece 1 with some of the sheet metal processing equipment that can be used in the process.

[0064] The shapes of the sheet metal structure 1, the main anvil tool 10, and the first auxiliary anvil tool 20 in Figures 3A to 3F are the same as those of the sheet metal structure 1, the main anvil tool 10, and the first auxiliary anvil tool 20 in Figures 1A to 1F and 2A to 2F. Therefore, detailed descriptions of the shapes of the sheet metal structure 1, the main anvil tool 10, and the first auxiliary anvil tool 20 in Figures 3A to 3F will be omitted.

[0065] In FIG. 3A , a first auxiliary forming tool 30 for use in forming a sheet metal structure is provided. The first auxiliary forming tool 30 has a tool surface 35 that contacts and restrains at least a portion of the second (top) surface 5 of the sheet metal workpiece 1. The tool surface 35 is the lower surface of the forming tool 30 in FIG. 3A . Also shown in FIG. 3A is a primary forming tool 40, which also has a tool surface 45 for contacting and restraining at least a portion of the second (top) surface 5 of the sheet metal workpiece 1. The tool surface 15 of the primary anvil tool 10 and the tool surface 45 of the primary forming tool 40 are configured to be substantially congruent with one another. Manufacturing processes, as described below in connection with FIGS. 3A and 3B , can utilize the primary forming tool 40 to exert greater control over the shaping of the sheet metal workpiece.

[0066] When the primary forming tool 30 and the first auxiliary forming tool 40 are present, the primary forming tool 30 and the first auxiliary forming tool 40 can both be connected to a second press plate for attachment to a metal forming press. As described below in connection with Figures 3B and 3C, the primary forming tool 40 is movable relative to the first auxiliary forming tool 30. Thus, when the primary auxiliary forming tool 30 and the first auxiliary forming tool 40 are connected to the second press plate, at least one of the forming tools 30, 40 is movably connected to the second press plate. The movably connection between the forming tool and the second press plate can be via, for example, a hydraulically or mechanically operated ram.

[0067] 3A and 3B, the flat sheet metal workpiece 1 of FIG. 3A is bent to form a first base region 50 and a second base region 60, which together form the base of the workpiece 1. In FIG. 3B, the base of the workpiece 1 is clamped between the main anvil tool 10 and the main forming tool 40, fixing the base in place relative to the main anvil tool 10 and the main forming tool 40. This fixes the sheet metal workpiece 1 prior to further forming, meaning that the base regions 50, 60 cannot move relative to the main anvil tool 10, thereby preventing movement of the base regions from accidentally deforming the sheet metal workpiece later in the process. Bending the workpiece 1 to form the first base region 50 and the second base region 60 can be performed by clamping the workpiece 1 between the tool surfaces 15, 45 of the main anvil tool 10 and the main forming tool 40, respectively. Performing the bending process in this manner is beneficial in that the bend 56 formed in the sheet metal workpiece 1 precisely conforms to the shape of the respective tool surfaces 15, 45. The process of clamping the base of the workpiece 1 between the primary anvil tool 10 and the primary forming tool 40 is performed by moving the primary anvil tool 10 and the primary forming tool 40 toward each other with the workpiece 1 disposed therebetween. The primary anvil tool 10 and the primary forming tool 40 continue to move toward each other until they contact the workpiece 1 and the base regions 50, 60 contact and conform to the tool surfaces 15, 45. The primary anvil tool 10 and the primary forming tool 40 continue to move toward each other until a clamping pressure equal to or greater than a first threshold clamping pressure is applied to the portion of the sheet metal workpiece 1 sandwiched between the respective tool surfaces 15, 45 of the tools 10, 40. The first threshold clamping pressure can be set depending on the Young's modulus and yield stress of the material of the sheet metal workpiece 1, and therefore how much pressure needs to be applied to the workpiece 1 during deformation steps later in the manufacturing process. Typically, the first threshold clamping pressure is 100 kPa or greater. Optionally, the clamping pressure can be set not to exceed the yield stress of the material forming the workpiece 1, as too much clamping pressure could result in unwanted thinning or tearing of portions of the workpiece.A clamping pressure exceeding the yield stress of the material forming the workpiece 1 may result in unwanted and unnecessary 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 cushion exerting the clamping pressure.

[0068] As shown in FIG. 3B, the sidewall portions 51, 61 of the workpiece 1 extend to one side of the portion of the workpiece 1 clamped between the main anvil tool 10 and the main forming tool 40, and the first auxiliary anvil tool 20 is positioned below the sidewall portions 51, 61.

[0069] 3C and 3D (which generally correspond to the shape of workpiece 1 in FIGS. 1C and 2C ), the first auxiliary forming tool 30 is brought into contact with first sidewall portion 51 and second sidewall portion 61, deforming them relative to first base region 50 and second base region 60. Specifically, FIG. 3C illustrates a point in the manufacturing process where the first auxiliary forming tool is positioned above second surface 5 of workpiece 1 and moves downward relative to workpiece 1 and main anvil tool 10 so that tool surface 35 of first auxiliary forming tool 30 contacts second surface 5 of the workpiece. FIG. 3D illustrates how forming tool 30 continues to move downward, thereby deforming sidewall portions 51, 61 and reducing the angle between the first surface 3 of each sidewall portion 51, 61 and the first surface 3 of that sidewall portion's respective base region 50, 60. A sidewall bend 57 that coincides with the chamfered edge is formed between the tool surface 15 of the main anvil tool and the sidewall 16. In the process of deforming the sidewall portions 51, 61, a bend region 55 of the workpiece 1 begins to form between the first sidewall portion 51 and the second sidewall portion 61.

[0070] 1D and 2D , the deployable regions of the sidewall portions 51, 61 are deformed by the first auxiliary forming tool 30 and contact and are restrained by the sidewall portion 16 of the main anvil tool 10 (see FIG. 2D ). The tool surface 35 of the first auxiliary forming tool 30 of FIGS. 3A-3F also includes an inverted “V” shaped portion that matches the shape of the tool surface 25 of the first auxiliary anvil tool 20, as shown in FIG. 3E . As the sidewall portions 51, 61 are deformed by the relative movement of the first auxiliary forming tool 30 and the workpiece 1, the folding region 55 is formed into a raised beak shape that contacts and is restrained by both the inverted “V” shaped portion 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 folding region 55 is interposed between and fully contacts 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 folding region 55 between the tool surfaces 35, 25 of the first auxiliary forming tool 30 and the first auxiliary anvil tool 20, respectively. The first auxiliary forming tool 30 stops moving downward when a clamping pressure equal to or greater than a second threshold is applied to the folding region 55. The second threshold clamping pressure can be set depending on the shear modulus of the material of the sheet metal workpiece 1 and, therefore, how much pressure needs to be applied to the workpiece 1 during a later shear deformation step in the manufacturing process. Typically, the second threshold clamping pressure is 100 kPa or greater. Optionally, the clamping pressure of the folding region 55 can be set so as not to exceed the yield stress of the material forming the workpiece 1. A clamping pressure exceeding the yield stress of the material forming the workpiece 1 may result in 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 cushion exerting the clamping pressure.

[0071] 3F next illustrates the process of sliding the first auxiliary forming tool 30 along the folding region 55 to cause shear material displacement therein, as described in connection with FIGS. 1E, 1F, 2E, and 2F, to further deform the folding region 55 and conform it to the unfolded regions of the sidewall portions 51, 61. Between FIGS. 3E and 3F, it is apparent that both the first auxiliary forming tool 30 and the first auxiliary anvil tool 20 slide downwardly at the same time and at the same speed relative to the main anvil tool 10, causing material at the ends of the raised folding region 55 to be pulled from the clamped portions and deformed to conform to the unfolded sidewall portions 51, 61, while the remainder of the raised portions of the folding region 55 remain 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, reducing the size of the raised portion of the folding region 55 as more material is pulled from the clamping area, until the material in the folding region 55 has been pulled completely through the forming tools and the folding region 55 conforms to the sidewall portions 51, 61. The movement of the first auxiliary forming tool 30 and the first auxiliary anvil tool 20 during the sliding process can be controlled independently of each other (but so that 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 imparting a sufficiently large pressure to the first auxiliary anvil tool 20 (either through the workpiece 1 clamped therebetween or through contact between the tools outside the periphery of the workpiece) to urge the first auxiliary anvil tool 20 to move downward with the forming tool 30.

[0072] 4A-4E, proceeding from FIG. 4A to FIG. 4E, illustrate various stages of the above manufacturing process performed to form a formed sheet metal structure having multiple bends at its base and corresponding multiple folding regions formed during the manufacturing process.

[0073] Similar to the examples described in connection with FIGS. 1A-1F, 2A-2F, and 3A-3F, workpiece 100 has opposing first and second surfaces 103 and 105, where the first and second surfaces are the lower (not visible) and upper surfaces of the sheet, respectively. The sheet metal has a peripheral edge 107. The shape of sheet metal workpiece 101 and the one or more peripheral edges 107 it has are not required and can be selected based on the shape of the formed sheet metal structure desired to be produced. At the stage of the process shown in FIG. 4A, workpiece 101 is flat, and a primary anvil tool 110 is provided having a tool surface 115 for contacting and restraining at least a portion of workpiece 101. The main anvil tool 110 further includes a sidewall 116 extending from the tool surface 115, and in FIG. 4A the edges where the sidewall 116 meets the tool surface 115 are chamfered to assist in smooth deformation of the sidewall portions 151, 161 at later stages of the process.

[0074] In the stage shown in Figure 4B, workpiece 101 is bent to form the base regions of the workpiece. In particular, workpiece 101 in Figure 4B includes first base region 150, second base region 160, third base region 170, and fourth base region 180, with bends 156, 166, and 176 present between adjacent base regions. In the examples of Figures 1A-1F, 2A-2F, and 3A-3F, bends 156 are such that first surface 3 of workpiece 1 is located at bend 156. However, in Figure 4B, there is a combination of concave and convex portions of first surface 103. Specifically, the first bend 156 is such that the first surface 103 of the workpiece 101 is convex thereat; the second bend 166 is such that the first surface 103 of the workpiece 101 is concave thereat; The third bend 176 is such that the first surface 103 of the workpiece 101 is concave thereat.

[0075] 1B, 2B, and 3B in that in FIG. 4B, sidewall portions extend from the base region not only on the side adjacent the edge 107 of the workpiece 101, but also on another side of the base region. More specifically, in FIG. 4B, there is a first sidewall portion 151, a second sidewall portion 161, a third sidewall portion 171, and a fourth sidewall portion 181, all of which extend from the same side of the respective base region 150, 160, 170, 180 toward the edge 107, and there are corresponding sidewall portions on the opposite side of the base region 150, 160, 170, 180 that extend from the base region 150, 160, 170, 180 toward the first through fourth sidewall portions 151, 161, 171, 181. Thus, when the manufacturing process is complete, the resulting shaped sheet metal structure has a "U" shaped cross section with two side walls extending from a non-planar base (see FIG. 4E). It can be appreciated that the complex bend arrangement at the base of workpiece 101 does not necessarily correlate to workpiece 101 having side wall portions extending from a base region on opposite sides of the base region to form a shaped sheet metal structure with a "U" shaped cross section. The two features are separable.

[0076] 4C illustrates a stage in the manufacturing process where the sheet metal workpiece 101 begins contacting the main anvil tool 110 and a first auxiliary forming tool (not shown) to deform sidewall portions 151, 161, 171, 181. FIG. 4C illustrates how the first, second, third, and fourth sidewall portions 151, 161, 171, 181 are deformed so that they are no longer coplanar with their respective base regions 150, 160, 170, 180. In FIG. 4C, the sidewall portions 151, 161, 171, 181 are deformed downwardly such that the first surface 103 of the workpiece 101 is concave between the base and the sidewalls (i.e., the angle between the first surface 103 of the first base region 150 and the first surface 103 of the first sidewall portion 151 is less than 180°, and similarly for other corresponding pairs of base regions and sidewall portions). In the process of deforming the sidewalls 151, 161, 171, 181, a stretched region 155 and two folded regions 165, 175 corresponding to the bends 156, 166, 176 are formed. In the case of the workpiece 101 of FIG. 4A, The stretched region 155 is where there is not enough material in the workpiece and where tearing is likely to occur if the method is not applied; The first fold region 165 is where excess material is present in the workpiece and where buckling / wrinkling would occur in the absence of the present method; The second fold region 175 is where there is excess material in the workpiece and where buckling / wrinkling would occur in the absence of this method.

[0077] 4C , deformation of the sidewall portions of base regions 150, 160, 170, 180 opposite first through fourth sidewall portions 151, 161, 171, 181 has also begun. A second auxiliary forming tool (not shown) may be provided to contact and restrain at least a portion of second surface 105 of sheet metal workpiece 101, and contacting the second auxiliary forming tool with sheet metal workpiece 101 deforms these opposing sidewall portions to form stretched regions and folded regions equivalent to stretched region 155, second folded region 165, and third folded region 175 visible in FIG. 4C . In some embodiments of the present invention, it may be desirable for the second auxiliary forming tool to be movable relative to main anvil tool 115 independently of the first auxiliary forming tool, for example, when the length of the sidewall portion deformed by the first auxiliary forming tool (i.e., the distance between the base region and the workpiece edge) differs from the length of the sidewall portion deformed by the second auxiliary forming tool. However, in other embodiments, the first and second auxiliary forming tools may be integrally formed with one another, such that fewer forming tools require independent control.

[0078] It can be seen that when bends 166, 176 are such that first surface 103 is concave between adjacent base regions, fold regions 165, 175 are formed adjacent these bends 166, 176, similar to fold region 55 illustrated in Figures 1C-1F, 2C-2F, and 3D-3F described above. In these fold regions, excess material is present in the workpiece, and buckling / wrinkling would otherwise occur when deforming the raised fold regions 165, 175. Second fold region 165 and third fold region 175 can be further deformed in the same manner as described above with respect to Figures 1E, 2E, and 3F. The first auxiliary forming tool can be slid progressively along the second and third folding regions 165, 175 to create shear material movement therein, with material moving from each folding region to one or both of the sidewall portions adjacent that folding region, and potentially to one or both of the base regions adjacent that folding region. One or more additional anvil tools, similar to the first auxiliary anvil tool 20 described in connection with Figures 2A-2F and 3A-3F, can be used to support the second and third folding regions 165, 175 and to assist the first auxiliary forming tool in further deforming the second and third folding regions 165, 175 without buckling / wrinkling the workpiece 101 in these regions. Figure 4D shows a stage in the process where further deformation of second fold region 165 and third fold region 175 has been partially completed, with the upper portions of the raised fold regions 165, 175 present in Figure 4C flattened in Figure 4D to conform with the unfolded sidewall portions 161, 171, 181, and the lower portions of fold regions 165, 175 still raised in Figure 4D and requiring further shear material displacement to conform fold regions 165, 175 with the adjacent unfolded sidewall portions 161, 171, 181. Although not visible in Figure 4D, equivalent steps in the manufacturing process can be performed on fold regions equivalent to second fold region 165 and third fold region 175 on the opposite side of the base from second fold region 165 and third fold region 175.

[0079] 1A-1F, 2A-2F, and 3A-3F, the example of FIGS. 4A-4E also includes a stretched region 155 formed adjacent to the first bend 156 where the first surface 103 of the sheet metal workpiece 101 is convex rather than concave. Thus, the material in the stretched region 155 is susceptible to tearing during the process of contacting the sheet metal workpiece 101 with the main anvil tool 110 and the first auxiliary forming tool to deform the sidewall portions 151, 161, 171, 181 relative to the base regions 150, 160, 170. In the prior art, this region 155 is referred to as a "stretched region" because the material in this region requires substantial stretching and thinning to deform to fit the sidewall portions. This is due to the increased surface area of ​​the sheet metal workpiece 101 required near the stretched region 155 to transition from the undeformed sidewall state shown in FIG. 4B to the deformed sidewall state shown in FIG. 4C.

[0080] However, in this embodiment, during the step of the manufacturing process where the first auxiliary forming tool contacts the sheet metal workpiece 101, the part can be stably deformed by in-plane shear material movement within the range of deformation that the material can withstand before substantial thinning or tearing occurs. The anvil tool and forming tool can be designed with appropriate tool radii according to conventional flanging tool design methods to enhance stable deformation in the stretched region 155. Although not visible in FIG. 4C , an equivalent step of the manufacturing process can be performed on a stretched region equivalent to stretched region 155 on the opposite side of base region 150, 160 from stretched region 155.

[0081] The resulting sheet metal structure 101 at the end of the manufacturing process is shown in FIG. 4E and includes two continuous sidewalls extending downward from a base, the sidewalls being on opposite sides of the base. While the base is non-planar (e.g., in FIG. 4E, it has four base regions that are not coplanar with one another), the sidewalls extending from the base are substantially planar (at least in the example shown in FIG. 4E). Here, both sidewalls lie in a plane that is approximately 90° offset from the plane of both base regions. Advantageously, as shown in FIG. 4E, the resulting sheet metal structure at the end of the manufacturing process requires minimal or no trimming after forming, compared to, for example, producing the same part using a deep drawing process. Furthermore, the above-described method can allow for reduced metal waste while maintaining satisfactory sheet quality (e.g., reducing or avoiding undesirable material deformations such as wrinkles or tears).

[0082] The features disclosed in the above description, or in the claims or accompanying drawings, may be expressed in their specific form, or in terms of means for performing a disclosed function, or a method or process for obtaining a disclosed result, as appropriate, and may be used individually or in any combination of such features to realize the invention in various of its forms.

[0083] While the present invention has been described in conjunction with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art upon review of this disclosure. Accordingly, the above exemplary embodiments of the invention are considered to be illustrative and not limiting. Various changes can be made to the described embodiments without departing from the spirit and scope of the invention.

[0084] For the avoidance of doubt, all theoretical explanations provided herein are provided for the purpose of enhancing the understanding of the reader, and the inventors do not wish to be bound by any of these theoretical explanations.

[0085] Any section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0086] Throughout this specification, including the claims, unless the context requires otherwise, the words "comprise" and "include," and variations such as "comprises," "comprising," and "including," will be understood to mean the inclusion of a stated integer or step or group of integers or steps, but not to the exclusion of other integers or steps or groups of integers or steps.

[0087] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, it will be understood that the particular value forms another embodiment by use of the antecedent "about." The term "about" with respect to numerical values ​​is arbitrary and means, for example, ±10%.

[0088] References In order to more fully describe and disclose the present invention and the art to which it pertains, one or more publications are cited above. Full citations for these publications are provided below. Each of these publications is incorporated herein by reference in its entirety. Horton, PM and Allwood, JM (2017): “Yield improvement opportunities for manufacturing automotive sheet metal components”, Journal of Materials Processing Technology, 249 78-88 [Explanation of symbols]

[0089] 1, 101 sheet metal workpiece 3, 103 First Surface 5, 105 Second Surface 7, 107 Periphery 10, 110 Main anvil tool 15, 115 Tool surface of main anvil tool 16 Main anvil tool sidewall 20 First auxiliary anvil tool 25 Tool surface of first auxiliary anvil tool 30 First auxiliary forming tool 35 Tool surface of first auxiliary forming tool 40 Main forming tool 45 Tool surface of main forming tool 50, 150 First base area 51, 151 first side wall portion 55, 165 First bending region 56, 156 First bend 60, 160 Second base area 61, 161 Second side wall portion 155 Stretching area 166 Second Bend 170 Third base region 171 Third side wall 175 Second bending area 176 Second Bend 180 Fourth Base Region 181 Fourth side wall

Claims

1. 1. A method for manufacturing a formed sheet metal structure, comprising the steps of: Providing a sheet metal workpiece having opposing first and second surfaces and at least one edge; providing a primary anvil tool having a tool surface for contacting and restraining at least a portion of the first surface of the sheet metal workpiece; bending the workpiece to form at least a first base region and a second base region having a bend therebetween, and restraining at least a portion of the base regions between a main anvil tool and a main forming tool to fix the base regions relative to the main anvil tool so that there is 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 restraining at least a portion of the second surface of the sheet metal workpiece; contacting the sheet metal workpiece with the first auxiliary forming tool to deform the first and second sidewall portions relative to the first and second base regions, thereby forming a first bend region in the sheet metal workpiece between the first and second sidewall portions; and Incrementally sliding the first auxiliary forming tool along the first bend region to cause displacement of shear material in the first bend region to further deform the first bend region. A method comprising:

2. 10. The method of claim 1, further comprising providing a first auxiliary anvil tool having a tool surface for contacting and restraining at least a portion of the first surface of the sheet metal workpiece in the first bend region.

3. The method further includes incrementally sliding the first auxiliary anvil tool along the first folding region; 3. The method of claim 2, wherein the step of progressively sliding the first auxiliary anvil tool along the first folding region is performed simultaneously with the step of sliding the first auxiliary forming tool along the first folding region to control deformation of the first folding region.

4. The method of claim 3 , wherein the incremental sliding of the first auxiliary anvil tool along the first folding region is performed by incremental sliding of the first auxiliary forming tool along the first folding region.

5. 5. The method of claim 2, wherein the main anvil tool and the first auxiliary anvil tool are each connected to a first press plate, and at least one of the main anvil tool and the first auxiliary anvil tool is movably connected to the first press plate.

6. the main anvil tool having a sidewall; the sidewall of the main anvil tool restrains at least a portion of the first surface of the first sidewall portion of the sheet metal workpiece and at least a portion of the first surface of the second sidewall portion of the sheet metal workpiece during the step of contacting the sheet metal workpiece with the first auxiliary forming tool; 6. The method of claim 1, wherein the sidewall of the main anvil tool restrains at least a portion of the first surface of the first folding region during the step of sliding the first auxiliary forming tool along the first folding region.

7. 7. The method according to claim 1, wherein bending the sheet metal workpiece to form the first base region and the second base region is carried out by clamping the sheet metal workpiece between respective tool surfaces of a main anvil tool and a main forming tool.

8. 8. The method according to claim 1, wherein the main forming tool and the first auxiliary forming tool are each connected to a second press plate, and at least one of the main forming tool and the first auxiliary forming tool is movably connected to the second press plate.

9. The method further includes bending the sheet metal workpiece to form a third base region having a second bend between the second base region and the third base region, a third sidewall portion extending between the third base region and the edge; contacting the sheet metal workpiece with the first auxiliary forming tool deforms the third sidewall portion relative to the third base region to form a second bend region in the sheet metal workpiece between the second sidewall portion and the third sidewall portion; The method of any preceding claim, further comprising the step of incrementally sliding the first auxiliary shaping tool along the second fold region to further deform the second fold region.

10. the first sidewall portion and the second sidewall portion are disposed on a first side of a base region; a fourth sidewall portion extending between the first base region and an edge of the sheet metal workpiece on another side of the base region, and a fifth sidewall portion extending between the second base region and the edge; The method comprises the steps of: providing a second auxiliary forming tool having a tool surface for contacting and restraining at least a portion of the second surface of the sheet metal workpiece; contacting the sheet metal workpiece with the second auxiliary forming tool to deform a fourth sidewall portion and a fifth sidewall portion relative to the first base region and the second base region, thereby forming a third bend region in the sheet metal workpiece between the fourth sidewall portion and the fifth sidewall portion; and sliding the second auxiliary forming tool progressively along the third bend region to cause displacement of shear material in the third bend region to further deform the third bend region. The method of any one of claims 1 to 9, further comprising:

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

12. A sheet metal processing apparatus for producing a shaped sheet metal structure from a sheet metal workpiece, the sheet metal workpiece having a first surface and a second surface opposed to each other and at least one edge, the shaped sheet metal structure having at least a first base region and a second base region having a bend therebetween, 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 processing apparatus comprising: a primary anvil tool having a tool surface for contacting and restraining at least a portion of the first surface of the sheet metal workpiece; a primary forming tool configured to constrain at least a portion of the base region together with the primary anvil tool; a first auxiliary forming tool having a tool surface for contacting and restraining at least a portion of the second surface of the sheet metal workpiece; Equipped with The first auxiliary forming tool comprises: contacting a sheet metal workpiece to deform the first and second sidewall portions relative to the base region 1 and the second base region, thereby forming a first bend region in the sheet metal workpiece between the first and second sidewall portions; and a sheet metal working device configured to slide along the first bend region and cause shear material movement in the first bend region to further deform the first bend region.

Images