Incremental forming tool head for internal and external synchronous reaming of plate pipe fitting and implementation method

Abstract

The invention provides an incremental forming tool head for internal and external synchronous chambering of plate and pipe fittings and an implementation method, the tool head comprises an internal chambering area, a transition shoulder, an external chambering area and a clamping area, and the internal chambering area and the external chambering area are used for internal and external synchronous chambering incremental forming of parts. The length of the lower portion of the inner reaming area ranges from 15 mm to 20 mm, the inner reaming area and the outer reaming area are connected through a transition shoulder, the reaming fillet radiuses of the inner reaming area and the outer reaming area range from 2 mm to 5 mm, and the radius of the clamping area ranges from 7.5 mm to 10 mm. Compared with the prior art, the tool head has the advantages that rapid internal and external synchronous reaming forming of sheet metal parts, pipe fittings and curved surfaces can be achieved through an incremental forming flexible manufacturing method, and the tool head is simple in structure, convenient to machine and operate, high in practicability and good in economic benefit; due to the fact that the forming process is mainly affected by pressure stress, the thickness distribution of a reaming area is more uniform through the pressure stress, the forming precision and the surface quality of a final workpiece are remarkably improved, and the cracking risk is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hole expanding tools for sheet metal parts, tube parts and curved surfaces, and in particular to a progressive forming tool head for synchronous hole expansion inside and outside a plate tube part and an implementation method. BACKGROUND

[0002] Progressive forming is a flexible forming technology without die that has been developed in recent years. It has been widely used in the fields of automobiles, aerospace, medical treatment and the like due to its flexible forming method, good performance, low cost and flexible forming for various materials. At present, many parts have the characteristics of hole expansion inside and outside, but stamping forming needs multi-station die to cooperate with processing, the die is expensive, it is difficult to avoid forming cracking and hole expansion interference, and it cannot be used for various complex part forming. When the traditional progressive forming tool head is used for synchronous hole expansion inside and outside sheet metal parts and tube parts, it is difficult to avoid severe thinning, and stress concentration is easily generated at the hole expansion corner to cause cracking, such as the ventilation port of an automobile transmission case, the fuel interface flange of a spacecraft and the joint shell of a bionic robot.

[0003] Chinese patent application CN119259834A proposes a stainless steel pipe forming device that uses three stamping heads with decreasing sizes to realize gradient stamping and hole expansion of the stainless steel pipe, adopts intermittent hole expansion to realize hole expansion of the stainless steel pipe with a thick wall, and improves the stamping and hole expansion qualification rate. Chinese patent CN203140666U discloses a press for stamping a ring part, which uses upper and lower anvil seats and an arc-shaped clamping plate to position a workpiece blank, and uses upper and lower perforated piston type oil cylinders to realize stamping and hole expansion of the ring part. Chinese patent CN218817627U proposes a self-lubricating bushing with inner and outer flanging, which is made by blanking, coiling, shaping, inner flanging and outer flanging of a corresponding composite material plate, and can form a sliding bearing with the characteristics of inner and outer flanging. Chinese patent CN214563068U discloses a one-time inner and outer flanging combined assembly die for a sealing ring for an aero-engine seal, which uses a flanging upper and lower die to complete the flanging forming of the inner and outer edges of the outer ring at one time, and ensures the assembly quality. However, the above many dies and methods can complete the inner and outer flanging forming of parts, but the die design is complex, only a single part can be formed, and the manufacturing cost is relatively high. SUMMARY

[0004] The present application is to overcome the defects of the prior art, and provides a progressive forming tool head for synchronous hole expansion inside and outside a plate tube part and an implementation method. The tool head applies pressure stress to the material by using hole expansion fillets and transition shoulders, and performs progressive forming by using contact instead of point contact, so that excessive thinning and stress concentration can be avoided, and the hole expansion thickness is relatively uniform.

[0005] The object of the present application can be achieved by the following technical solutions. The first object of the present application is to provide a progressive forming tool head for synchronous internal and external expanding of plate tube, comprising an internal expanding area, a transition shoulder, an external expanding area and a clamping area; the internal expanding area, the transition shoulder, the external expanding area and the clamping area are connected in sequence; the internal expanding area and the external expanding area are used for synchronous internal and external expanding of plate tube.

[0006] Further, the length of the internal expanding area ranges from 15 to 20 mm, which is used to meet the internal expanding height requirement; the internal expanding area comprises an expanding fillet (internal expanding fillet), and the radius of the expanding fillet ranges from 2 to 5 mm, which is used for internal expanding of plate tube and curved surface.

[0007] Further, the external expanding area comprises an expanding fillet (external expanding fillet), and the radius of the expanding fillet ranges from 2 to 5 mm, which is used for external expanding of plate tube and curved surface.

[0008] Further, the internal expanding area and the external expanding area are connected through the transition shoulder.

[0009] Further, the transition shoulder is a stepped transition area between the internal expanding area and the external expanding area, comprising transition fillets arranged on both sides of the internal expanding area and the external expanding area, radial stepped planes between the internal and external expanding areas and the transition fillets, and an axial cylindrical straight wall between the two transition fillets; the radius of the transition fillet ranges from 0.5 to 1 mm, which is used to prevent plate tube and curved surface from being unstable and wrinkled; the radial length between the transition fillet and the internal and external expanding areas ranges from 2 to 5 mm; and the axial length between the two transition fillets ranges from 5 to 10 mm.

[0010] Further, the clamping area is used for clamping of a clamp, and the vertical rod length of the clamping area ranges from 100 to 150 mm, and the radius of the clamping area ranges from 7.5 to 10 mm.

[0011] The second object of the present application is to provide a progressive forming implementation method for synchronous internal and external expanding of plate tube and curved surface, which is implemented by using the progressive forming tool head, and comprises the following steps. S1, determining the length of the lower part of the internal expanding area, the radius of the expanding fillet of the internal expanding area, the radial length of the transition shoulder and the radius of the transition fillet according to the expanding height of the internal expanding area of the plate tube to be formed; S2, determining the radius of the expanding fillet of the external expanding area, the radial length of the transition shoulder, the radius of the transition fillet, the axial length of the transition shoulder, and the length and radius of the vertical rod of the clamping area according to the expanding height of the external expanding area of the plate tube to be formed and the performance of the formed material; S3, designing the internal expanding layer cutting track and the external expanding layer cutting track according to the internal and external expanding parameters of the plate tube to be formed. S4, after the manual operation of the numerically controlled machine tool completes the centering of the to-be-inner-holed area, the radial step plane of the transition shoulder on the side of the incremental forming tool head is aligned with the edge of the to-be-inner-holed area, the machine tool is started, and the incremental forming tool head expands along the inner-holed layer cutting track from inside to outside to perform inner-holed forming; S5, after the inner-holed forming is completed, the centering of the to-be-outer-holed area is completed, then the radial step plane of the transition shoulder on the side of the incremental forming tool head is aligned with the edge of the to-be-outer-holed area, the machine tool is started, and the incremental forming tool head expands along the outer-holed layer cutting track to perform outer-holed forming; S6, after the incremental forming local plastic deformation is completed, the incremental forming tool head is lifted, and the plate pipe piece after incremental forming is taken off, so that the plate pipe piece with inner and outer holed characteristics is finally obtained.

[0012] Further, in step S3, the inner-holed layer cutting track and the outer-holed layer cutting track each include the following settings: The tool track is spiral-shaped, travels from inside to outside, and the horizontal step distance is 0.1-0.5 mm.

[0013] Further, in step S3, the incremental forming tool head does not need to rotate, and in the curved hole forming, the inner-holed area and the outer-holed area are perpendicular to the curved surface.

[0014] Further, before step S4, the following steps are performed: The plate pipe piece is fixed on the tooling of the numerically controlled machine tool, and needs to be clamped around.

[0015] Further, the plate pipe piece is a plate material (sheet metal piece) and / or a pipe material (pipe piece).

[0016] Further, the present application provides a kind of sheet metal piece and pipe piece inner and outer synchronous hole forming incremental forming implementation method, including the following steps: S1, according to the hole expansion height of the to-be-formed inner-holed area, the length of the lower part of the inner-holed area, the hole expansion fillet radius and the radial length of the transition shoulder are determined; S2, according to the hole expansion height of the to-be-formed outer-holed area, the performance of the formed material, the hole expansion fillet radius of the outer-holed area, the radial length of the transition shoulder, the transition fillet radius, the axial length of the transition shoulder and the length and radius of the vertical rod of the clamping area are determined; S3, according to the inner and outer holed parameters to be formed, the inner-holed layer cutting track and the outer-holed layer cutting track are designed, the tool track is spiral-shaped, travels from inside to outside, the horizontal step distance is 0.1-0.5 mm, and the tool head does not need to rotate; S4, the plate material and the pipe material are fixed on the tooling of the numerically controlled machine tool, and need to be clamped around; S5, after the manual operation of the numerically controlled machine tool completes the centering of the to-be-inner-holed area, the radial step plane of the transition shoulder on the side of the tool head is aligned with the edge of the to-be-inner-holed area, the machine tool is started, and the tool head expands along the inner-holed track from inside to outside to perform inner-holed forming; S6, after the inner hole forming is finished, the numerical control machine tool is manually operated to complete the centering of the outer hole forming area, then the radial step plane of the transition shoulder on the tool head is aligned with the edge of the outer hole forming area, the machine tool is started, and the tool head expands along the outer hole forming track to perform the outer hole forming; S7, after the forming is completed, the tool head is lifted, and the part is removed, and finally a component with inner and outer hole forming features is obtained.

[0017] The application relates to a progressive forming tool head for synchronous inner and outer hole forming of plate pipes and an implementation method. In order to meet the inner hole height requirement, the lower part of the inner hole forming area has a length range of 15-20 mm, the inner and outer hole forming areas are connected through the transition shoulder, the radial step plane of the transition shoulder is connected with the axial cylindrical straight wall through a transition round corner with a radius range of 0.5-1 mm, the clamping area has a radius range of 7.5-10 mm due to the requirement of high rigidity and horizontal bearing capacity of the clamping area. Based on the above innovations of the tool head, the flexible manufacturing method of the progressive forming can realize the synchronous inner and outer hole forming of sheet metal parts, pipes and curved surfaces, the tool head has simple structure, convenient processing operation, high practicability and good economic benefits; during the forming process, the thickness distribution of the hole forming area is more uniform under the action of the compressive stress, the forming precision and surface quality of the final part are significantly improved, and the cracking risk is effectively reduced.

[0018] Compared with the prior art, the application has the following beneficial effects: 1) The progressive forming tool head for synchronous inner and outer hole forming of plate pipes and the implementation method have the advantages that, compared with traditional stamping forming, the method can realize the synchronous inner and outer hole forming of holes with different diameters, is simple and easy to implement, does not need a die, can avoid forming cracking and hole forming interference, has good forming performance and low manufacturing cost.

[0019] 2) Compared with traditional progressive forming, the progressive forming tool head for synchronous inner and outer hole forming of plate pipes and the implementation method can avoid excessive thinning and stress concentration by applying compressive stress to the material through hole forming round corners and transition shoulders and performing progressive forming through belt contact instead of point contact, and the hole forming thickness is more uniform.

[0020] 3) The progressive forming tool head for synchronous inner and outer hole forming of plate pipes and the implementation method realize innovations on the tool head, realize the synchronous inner and outer hole forming of sheet metal parts and pipes through the circular arc interface features, improve the forming quality and processing efficiency of the parts, and expand the application range of the progressive forming. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Fig. 1 is a schematic diagram of the cross-sectional structure of the tool head of the present application; Figure 2 Fig. 2 is a schematic diagram of the structure of the sheet metal part fixed on the machine tool; Figure 3 Fig. 3 is a schematic diagram of the inward hole expansion process by using the method of the present application on the sheet metal part; Figure 4 Fig. 4 is a schematic diagram of the outward hole expansion process by using the method of the present application on the sheet metal part; Figure 5 Fig. 5 is a schematic diagram of the finished sheet metal part after the forming by using the method of the present application; Figure 6 Fig. 6 is a schematic diagram of the outward hole expansion process by using the method of the present application on the pipe; Figure 7 Fig. 7 is a schematic diagram of the finished pipe after the forming by using the method of the present application; Figure 8 Fig. 8 is a schematic diagram of the enlarged size of the tool head of the present application; Reference signs: 1, inner hole expansion area, 2, transition shoulder, 3, outer hole expansion area, 4, clamping area, 5, sheet metal part, 6, tooling, 7, pipe. DETAILED DESCRIPTION

[0022] The present application will be described in detail below in conjunction with the drawings and specific embodiments. In the technical solution, the component models, material names, connection structures, control implementation methods, algorithms and other features not explicitly described are considered as common technical features disclosed in the prior art.

[0023] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and other terms should be understood in a broad sense, for example, can be fixed connection, can be detachable connection, or integrated; can be mechanical connection, can be electrical connection; can be directly connected, can be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0024] It is to be noted that the terms such as first and second, etc. are used herein merely to differentiate one entity or operation from another entity or operation, and do not necessarily require or imply there is any such actual relationship or order between these entities or operations. Also, the terms "include", "contain" or any other variants thereof are intended to cover the non-exclusive inclusion, so that the process, implementation method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, implementation method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, implementation method, article or device including the element.

[0025] The content of the present application will be further described in detail below in conjunction with specific embodiments and drawings. The following embodiments and features in the embodiments can be combined with each other without conflict.

[0026] Embodiment Taking sheet metal part 5 and pipe part 7 (pipe part 7 is a round pipe part) as an example, as shown in the drawings, the present embodiment provides a progressive forming tool head for synchronous inner and outer hole expansion of plate and pipe parts, which comprises an inner hole expansion area 1, a transition shoulder 2, an outer hole expansion area 3 and a clamping area 4. The inner hole expansion area 1, the transition shoulder 2, the outer hole expansion area 3 and the clamping area 4 are connected in sequence. Figure 1 The inner hole expansion area 1 and the outer hole expansion area 3 are connected through the transition shoulder 2.

[0027] The transition shoulder 2 is a stepped transition area between the inner hole expansion area 1 and the outer hole expansion area 3, which comprises a transition fillet arranged on both sides of the inner hole expansion area 1 and the outer hole expansion area 3, a radial stepped plane between the inner and outer hole expansion areas and the transition fillet, and an axial cylindrical straight wall located between the two transition fillets.

[0028] The inner hole expansion area 1 and the outer hole expansion area 3 are used for synchronous inner and outer hole expansion progressive forming of sheet metal and pipe materials (i.e. sheet metal part 5 and pipe part 7).

[0029] The clamping area 4 is used for clamping the tool head, which is required to have high rigidity and horizontal bearing capacity.

[0030] The present embodiment further provides a progressive forming method for synchronous inner and outer hole expansion of plate and pipe parts, which takes the progressive forming of sheet metal part 5 and pipe part 7 as an independent process, comprising the following steps:

[0031] ​S1, according to the material of the sheet metal part 5 and the pipe 7 to be formed, the process parameters and the forming specifications, the length H1 of the inner hole expanding area 1, the hole expanding fillet radius R1 of the inner hole expanding area 1, the radial length L of the transition shoulder and the transition fillet radius r, and the hole expanding fillet radius R3 of the outer hole expanding area 3, the radial length L of the transition shoulder, the transition fillet radius r and the axial length H2 of the transition shoulder are determined, as shown in Figure 8 To meet the inner hole expanding height requirement, the length H1 of the inner hole expanding area 1 is 15 mm, to prevent sheet metal and pipe instability wrinkling, the radial length L of the transition shoulder of the inner hole expanding area 1 and the outer hole expanding area 3 is 3 mm, the axial length H2 of the transition shoulder is 10 mm, the transition fillet radius r is 0.5 mm, to realize the inner and outer synchronous hole expanding of sheet metal and pipe, the hole expanding fillet radius R1 of the inner hole expanding area 1 and the hole expanding fillet radius R3 of the outer hole expanding area 3 are both 5 mm; S2, according to the material properties of the sheet metal part 5 and the pipe 7 to be formed and the hole expanding height of the outer hole expanding area, the length and radius of the vertical rod of the clamping area 4 are determined. Because the area is subjected to a larger horizontal load, it is required to have higher stiffness and horizontal load capacity, the length of the vertical rod is 100 mm, and the radius is 7.5 mm; S3, according to the required inner and outer hole expanding parameters, the inner hole expanding layer cutting trajectory and the outer hole expanding layer cutting trajectory are designed by using UG software modeling, the tool head in the trajectory does not need to rotate, the tool path is spiral, and the tool path travels from inside to outside, the horizontal step is 0.1 mm, after the tool path is generated, the trajectory is determined to be correct through simulation and NcViewer software, and is imported into the numerical control machine tool; S4, the tool head of the present application is installed on the numerical control machine tool, then the sheet metal part 5 and the pipe 7 are respectively fixed on the numerical control machine tool tooling 6, and are clamped around to avoid displacement of the sheet metal part 5 and the pipe 7 due to stress during the forming process, which leads to the decline of the forming quality and the uneven hole expanding thickness, as shown in Figure 2 , Figure 2 The fixing process of the pipe 7 is the same as that of the sheet metal part 5; S5, as shown in Figure 3 , Figure 3 The inner hole expanding forming process of the pipe 7 is the same as that of the sheet metal part 5, after the centering of the area to be inner hole expanded is completed by manually operating the numerical control machine tool, the radial step plane of the transition shoulder 2 on the inner hole expanding area 1 side of the tool head is aligned with the edge of the area to be inner hole expanded, the machine tool is started, the tool head expands from inside to outside along the inner hole expanding layer cutting trajectory to form inner hole expanding, the initial feed speed percentage of the numerical control machine tool is set to 100%, when the hole expanding height is about 3 mm, the forming situation is closely observed, the feed speed percentage can be set to 50% to avoid hole cracking; S6, as shown in Figure 4 , 6 , Figure 4 The sheet metal part 5 is taken as an example, Figure 6With pipe 7 as an example, after the inner hole expansion forming is completed, the numerical control machine tool is manually operated to complete the centering of the outer hole expansion area, then the transition shoulder 2 radial step plane on the outer hole expansion area 3 side of the tool head is aligned with the edge of the outer hole expansion area, the machine tool is started, and the tool head expands along the outer hole expansion layer cutting track to form the outer hole expansion. Similarly, the initial feed speed percentage of the numerical control machine tool is set to 100%, and when the hole expansion height is about 3mm, the forming situation is closely observed, the feed speed percentage can be set to 50% to avoid hole expansion cracking; S7, after the forming is completed, the tool head is lifted, the part is taken down (the sheet metal part 5 after the forming is completed and the pipe 7 after the forming is completed), and finally a component with inner and outer hole expansion characteristics is obtained, wherein the sheet metal part 5 after the forming is completed is as shown in Figure 5 , and the pipe 7 after the forming is completed is as shown in Figure 7 .

[0032] The above description of the embodiments is to facilitate the understanding and use of the invention by ordinary skilled in the art. Those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art according to the disclosure of the present application without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. A progressive forming tool head for simultaneous internal and external reaming of plate and tube fittings, characterized in that, It includes an inner enlarged hole area (1), a transition shoulder (2), an outer enlarged hole area (3), and a clamping area (4); The inner expansion area (1), transition shoulder (2), outer expansion area (3) and clamping area (4) are connected in sequence; The inner expansion zone (1) and outer expansion zone (3) are used for the synchronous inner and outer expansion of the plate and tube fittings for progressive forming.

2. The progressive forming tool head for simultaneous internal and external reaming of plate and tube fittings according to claim 1, characterized in that, The length of the inner expansion area (1) is 15~20mm, which is used to meet the height requirements of the inner expansion. The inner expansion area (1) includes an expansion fillet with a radius of 2~5mm, which is used for inner expansion of plates, tubes and curved surfaces.

3. The progressive forming tool head for simultaneous internal and external reaming of plate and tube fittings according to claim 1, characterized in that, The external expansion area (3) includes an expansion fillet with a radius of 2-5 mm, which is used for expanding holes in plates, tubes and curved surfaces.

4. The progressive forming tool head for simultaneous internal and external reaming of plate and tube fittings according to claim 1, characterized in that, The inner expansion area (1) and the outer expansion area (3) are connected by a transition shoulder (2).

5. The progressive forming tool head for simultaneous internal and external reaming of plate and tube fittings according to claim 4, characterized in that, The transition shoulder (2) is a step transition area between the inner expansion area (1) and the outer expansion area (3), including transition fillets on both sides of the inner expansion area (1) and the outer expansion area (3), a radial step plane between the inner and outer expansion areas and the transition fillets, and an axial cylindrical straight wall between the two transition fillets. The radius of the transition fillet is in the range of 0.5~1mm, which is used to prevent plate and tube fittings and curved surfaces from becoming unstable and wrinkling; The radial length between the transition fillet and the inner and outer expansion zones is 2~5mm. The axial length between the transition fillets ranges from 5 to 10 mm.

6. The progressive forming tool head for simultaneous internal and external reaming of plate and tube fittings according to claim 1, characterized in that, The clamping area (4) is used for clamping by the fixture. The vertical rod of the clamping area (4) has a length of 100~150mm and a radius of 7.5~10mm.

7. A method for achieving incremental forming of plate and tube fittings and curved surfaces with simultaneous internal and external reaming using the incremental forming tool head as described in any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Based on the expansion height of the inner expansion area of ​​the required plate and tube fitting, determine the length of the lower part of the inner expansion area (1), the expansion radius of the inner expansion area (1), the radial length of the transition shoulder (2), and the transition radius. S2. Based on the expansion height of the outer expansion area of ​​the required plate and tube fitting and the properties of the forming material, determine the expansion radius of the outer expansion area (3), the radial length of the transition shoulder (2), the axial length of the transition shoulder (2), the transition radius, and the length and radius of the vertical rod of the clamping area (4); S3. Based on the internal and external hole expansion parameters of the required plate and tube fittings, design the internal hole expansion layer tangent trajectory and the external hole expansion layer tangent trajectory. S4. After completing the centering of the area to be internally expanded, align the radial step plane of the transition shoulder (2) on the side of the internally expanded area (1) of the progressive forming tool head with the edge of the internally expanded hole, start the machine tool, and the progressive forming tool head expands from the inside to the outside along the internally expanded layer tangent trajectory to form the internally expanded hole. S5. After the internal hole expansion is completed, the area to be expanded is aligned. Then, the radial step plane of the transition shoulder (2) on the side of the external hole expansion area (3) of the progressive forming tool head is aligned with the edge of the external hole to be expanded. The machine tool is started and the progressive forming tool head expands along the external hole expansion layer tangent trajectory to form the external hole. S6. After the cumulative local plastic deformation of the progressive forming is completed, lift the progressive forming tool head and remove the plate and tube that has completed the progressive forming, and finally obtain the plate and tube with both internal and external hole expansion characteristics.

8. The progressive forming method for simultaneously expanding holes inside and outside curved surfaces of plate and tube fittings according to claim 7, characterized in that, In step S3, the inner hole expansion layer tangent trajectory and the outer hole expansion layer tangent trajectory both include the following settings: The toolpath is spiral-shaped and moves from the inside out, with a horizontal step distance of 0.1~0.5mm.

9. The progressive forming method for simultaneously expanding holes inside and outside curved surfaces of plate and tube fittings according to claim 7, characterized in that, In step S3, the progressive forming tool head does not need to rotate. In the surface reaming, the inner reaming area (1) and the outer reaming area (3) are perpendicular to the surface.

10. The progressive forming method for simultaneously expanding holes inside and outside curved surfaces of plate and tube fittings according to claim 7, characterized in that, Before step S4, perform the following steps: Fix the plate and pipe fittings onto the tooling (6) and clamp them tightly around the perimeter; The plate and tube fittings are one or more of plate material (5) and tube material (7).

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