Method for finishing a stretch-bent profile frame

Abstract

The application discloses a kind of drawing bending section bar frame finishing methods, comprising the following steps: S1, adjusting drawing bending type height, S2, drawing bending correction;S3, manual finishing bus perpendicularity;S4, manual finishing radian.The drawing bending type height step of the application can inhibit the warping of assembly end surface caused by the uneven elongation of section bar;Drawing bending correction step is conducive to ensuring the radian of section bar;Manual finishing bus perpendicularity step is more labor-saving and efficient, and has minimal impact on remaining dimensions and geometric tolerance;Manual finishing radian step uses "put" to make the final finishing of radian, which makes it easier to fit the template;Overall finishing workload is minimal, and has little impact on section bar surface quality;Side bending edge is more convenient to polish than vertical bending edge, and is more labor-saving and efficient.

Description

Technical Field

[0001] This invention belongs to the field of profile bending and trimming technology, specifically relating to a method for trimming bent profile frames. Background Technology

[0002] Aerospace-grade aluminum alloy profile frames can be categorized into inner-bend frames and outer-bend frames based on the bending direction of their side bends. Outer-bend frames have their side bends on the outer side of the bend. The most commonly used profile type is the right-angle profile, used for producing end frames at both ends of shell sections. Typical characteristics include: a longer profile, forming a 180° semi-circle; thicker side bends at the mating surfaces and thinner vertical bends with a slight angle, becoming thinner towards the outer edge. Inner-bend frames, during bending, it is easier to confine the side bend within the groove of the bending die. The vertical bend adheres tightly to the die surface as the bending process unfolds, resulting in better forming and less trimming required.

[0003] When the outer bending frame is bent, its side bending edge is in a relatively free state except for the two ends that are clamped by clamps. When the profile is unloaded and placed on the platform to check various technical indicators, it will be found that the shape of each cross section of the profile is qualified, that is, the right angle of the profile has not been deformed, and the flatness of the assembly end face is very good, with a small gap with the platform. However, when the perpendicularity of the generatrix to the assembly end face is checked on the platform with a right-angle ruler, a gap of 1~2mm will be detected, and the gap is larger closer to the outer edge of the vertical bending edge.

[0004] The profiles are typically 7A09 ultra-hard aluminum profiles, which are hardened through quenching and bending deformation. The usual method for adjusting the perpendicularity of the generatrix is ​​as follows: one hand holds a shim block on the outside of the vertical bend of the profile, while the other hand uses a hammer to tap the inside of the vertical bend point by point. After the perpendicularity of the generatrix is ​​corrected, the 90° angle of the profile section will increase. However, this method relies on the deformation of the thin-walled portion of the vertical bend to affect the deformation of the thick-walled portion of the side bend. The conversion efficiency of the adjustment amount to the adjustment effect is low, and the amount of hammering required for manual adjustment is large, resulting in poor profile surface quality. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical problems and to control the shape accuracy of the profile by bending and straightening and manual hammering, thereby reducing the amount of trimming. A method for trimming a bent profile frame is proposed.

[0006] A method for trimming a bent profile frame includes the following steps: S1. Adjust the height of the bending tire: Adjust the height of the bending tire to be lower than the normal height to the preset value; S2, Bending and Shaping: Clamp the profile with clamps and bend it according to the preset trajectory to increase the elongation of the fibers at the root of the bottom surface of the side bend of the profile. Unload after the trajectory loading is completed. S3. Manual adjustment of busbar verticality: Turn the profile over and place it on the platform. Use a hammer to tap the bottom root of the side bend of the profile at the first tapping point to make the fibers stretch evenly. After tapping, turn the profile over so that the vertical bend is facing up and check the busbar verticality. S4. Manually adjust the curvature: Referring to the curvature template, use a hammer to tap the outer edge of the profile side bend point by point at the second set of tapping points, so that the curvature of the profile and the curvature template are deformed segment by segment until they are consistent with the curvature template.

[0007] As a preferred embodiment, the normal height in S1 is when the bottom surface of the side bend of the profile is in contact with the bottom plate of the bending jig at the beginning of the bending process.

[0008] As a preferred embodiment, the bending die includes a die body and a cover plate disposed above the die body; in step S1, when the height of the bending die is lower than the normal height, the two sides of the profile will bend upward at a small angle during the bending process. As the bending process proceeds, the profile will smoothly slide into the bending die along the guide surface of the cover plate, and the vertical bending edge of the profile will gradually and tightly fit with the die body to form a shape. The preset value needs to be set according to the material and cross-sectional shape of the profile.

[0009] As a preferred method, after the trajectory loading in step S2 is completed, the clamp should be held for a certain period of time before unloading.

[0010] As a preferred embodiment, in step S3, a hammer is used to strike the first group of striking points uniformly point by point; in step S4, a hammer is used to strike the second group of striking points uniformly point by point.

[0011] The present invention has the following advantages: The invention minimizes the overall trimming workload, has little impact on the surface quality of the profile, and makes side bends easier to grind than vertical bends, resulting in greater efficiency and less effort. 1. Adjusting the height of the bending die can increase the elongation rate at the root of the vertical bend of the profile during bending, reduce the unevenness of fiber elongation in different fiber layers on the vertical bend of the profile, and make the fiber elongation at the outer edge of the vertical bend close to the bottom surface of the side bend of the profile, thus inhibiting the warping of the assembly end face caused by uneven elongation of the profile. 2. The stretching and bending process allows the profile to undergo more plastic deformation and reduce elastic recovery under continuous tensile stress, which helps to ensure the curvature of the profile. 3. The manual adjustment of the perpendicularity of the busbar further promotes the elongation of the fiber at the root of the side bend of the profile to be consistent with the outer edge of the vertical bend, eliminating the warping of the assembly end face. Compared with the adjustment method of tapping from the inside to the outside of the bend with pads, it is more labor-saving and efficient, and has the least impact on other dimensions and geometric tolerances. 4. Manually adjust the curvature step: The curvature "released" by stretching the fibers at the root of the side bend in the previous step is "contracted" to match the template by stretching the fibers at the head of the side bend. For this type of external bend frame, using "release" to make the final adjustment of the curvature makes it easier to fit the template. Attached Figure Description

[0012] Figure 1 A flowchart of the bending profile frame trimming method provided by the present invention; Figure 2 Schematic diagram of positional relationships during the bending process; Figure 3 This is a schematic diagram of the profile cross-section; Figure 4 This is a partial cross-sectional view of the main structure of the bending type tire; Figure 5 A schematic diagram of the tapping points for manually adjusting the verticality of the profile busbar; Figure 6 A diagram illustrating the tapping points for manually trimming the curvature of profiles.

[0013] Among them, 1 is the clamp, 2 is the profile, 3 is the bending jig, 4 is the platform, 5 is the first set of striking points, 6 is the arc template, 7 is the second set of striking points, 21 is the root of the bottom surface of the side bend of the profile, 22 is the bottom surface of the side bend of the profile, 23 is the side bend of the profile, 24 is the vertical bend of the profile, 25 is the straight surface of the vertical bend of the profile, 26 is the outer edge of the vertical bend of the profile, 31 is the base plate, 32 is the jig body, and 33 is the cover plate. Detailed Implementation

[0014] To make the technical means, creative features, achieved objectives, and effects of this invention readily understandable, embodiments of the invention are provided below for detailed description. It should be noted that these embodiments are only for further illustration and should not be construed as limiting the scope of protection of this invention. Those skilled in the art can make non-essential improvements and adjustments based on the content of this invention.

[0015] like Figures 1-6 As shown, a method for trimming a bent profile frame includes the following steps: S1. Adjust the height of the bending tire: Adjust the height of the bending tire 3 to be lower than the normal height to the preset value; At the beginning of the bending process, the normal height is when the bottom surface 22 of the side bend of the profile is in contact with the bottom plate 31 of the bending jig 3. When the height of the bending jig 3 is lower than the normal height, the two sides of the profile 2 will be tilted upward at a small angle during the bending process. As the bending process proceeds, the profile will slide smoothly into the bending jig 3 along the guide surface of the cover plate 33, and the straight surface 25 of the vertical bend of the profile 2 will gradually be tightly fitted with the jig body 32 to form a shape. The preset value needs to be set according to the material and cross-sectional shape of the profile 2. S2, Bending and Shaping: Clamp the profile 2 with clamp 1 and bend it according to the preset trajectory to increase the elongation rate of the fibers at the root 21 of the bottom surface of the side bend of the profile. After the trajectory loading is completed, clamp 1 should be held for a certain period of time before unloading. S3. Manually adjust the verticality of the busbar: Turn the profile 2 over and place it on the platform 4. Use a hammer to strike the root 21 of the bottom surface of the side bend of the profile 2 at the first set of striking points 5 to make its fibers stretch evenly. After the striking is finished, turn the profile 2 over so that the vertical bend 24 faces upward and check the verticality of the busbar. S4. Manually adjust the curvature: Referring to the curvature template 6, use a hammer to tap the outer edge of the side bend 23 of the profile 2 point by point at the second set of tapping points, so that the curvature of the profile 2 and the curvature template 6 are deformed segment by segment until they are consistent with the curvature template 6.

[0016] The hammer used for striking is made of a material with higher hardness than profile 2, resulting in a more pronounced material flow effect. The hammer marks on profile 2 can be polished to a smooth transition with the surrounding surface without affecting the mechanical properties and aesthetics of profile 2. The interval and force of the hammer strikes should be selected based on the actual situation.

[0017] The warping principle is as follows: the cross-section of the vertical bend edge is thinner closer to the outer edge. When bending, the fibers at this position are more easily stretched than the inner side and the side bend edge 23 of the profile. The outer side of the vertical bend edge 24 of the profile is more easily stretched than the inner side. The uneven elongation of fibers at different height layers causes the vertical bend edge of the entire frame to deform towards the inside of the bending radius, which in turn causes the entire frame to deform perpendicular to the bending plane. The side bend edge of the frame will be driven to warp along with the side bend edge.

[0018] The reason for poor perpendicularity of the busbar is that when the warped profile 2 is placed on the platform, due to the large weight of the profile 2, the gap between the bottom surface 22 of the side bend and the platform 4 will become smaller, causing the deformation that was originally tilted inward towards the bending radius to be tilted outward towards the bending radius, resulting in poor perpendicularity of the busbar.

[0019] The principle of the impact on subsequent assembly is as follows: Due to its own weight, the profile 2 undergoes elastic deformation of the vertical assembly end face on the platform 4. Traditional finishing methods cannot eliminate this elastic deformation, and the existence of this elastic deformation has a significant impact on manual finishing. During subsequent horizontal assembly, the recovery of this elastic deformation will be manifested, resulting in a deterioration in the flatness of the end face and affecting the assembly.

[0020] It should be noted that the method of this invention is applicable to general bending processes of externally curved frame profiles and is not a limitation on the number of bending operations. Furthermore, it should be noted that in the description of this invention, the terms "release" and "retract" refer to sheet metal techniques and are common knowledge in the art. Terms such as "upper," "lower," "inner," and "outer," indicating directional or positional relationships, are based on the directional or positional relationships shown in the accompanying drawings and are used only for convenience of description, not to indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

Claims

1. A method of finishing a stretch-bent profile frame, characterized in that, Includes the following steps: S1. Adjust the height of the bending tire: Adjust the height of the bending tire to be lower than the normal height to the preset value; S2, Bending and Shaping: Clamp the profile with clamps and bend it according to the preset trajectory to increase the elongation of the fibers at the root of the bottom surface of the side bend of the profile. Unload after the trajectory loading is completed. S3. Manual adjustment of busbar verticality: Turn the profile over and place it on the platform. Use a hammer to tap the bottom root of the side bend of the profile at the first tapping point to make the fibers stretch evenly. After tapping, turn the profile over so that the vertical bend is facing up and check the busbar verticality. S4. Manually adjust the curvature: Referring to the curvature template, use a hammer to tap the outer edge of the profile side bend point by point at the second set of tapping points, so that the curvature of the profile and the curvature template are deformed segment by segment until they are consistent with the curvature template.

2. A stretch-drawing profile frame finishing method according to claim 1, characterized in that: The normal height in S1 is when the bottom surface of the profile side bend is in contact with the bottom plate of the bending jig at the beginning of the bending process.

3. The method for trimming a bent profile frame according to claim 1, characterized in that: The bending die includes a die body and a cover plate disposed above the die body; in step S1, when the height of the bending die is lower than the normal height, the two sides of the profile will bend upward at a small angle during the bending process. As the bending process proceeds, the profile will smoothly slide into the bending die along the guide surface of the cover plate, and the vertical bending edge of the profile will gradually and tightly fit with the die body to form a shape. The preset value needs to be set according to the material and cross-sectional shape of the profile.

4. The method for trimming a bent profile frame according to claim 1, characterized in that: After the trajectory loading in S2 is completed, the clamps need to be held for a certain period of time before being unloaded.

5. The method for trimming a bent profile frame according to claim 1, characterized in that: In step S3, a hammer is used to strike the first group of striking points uniformly point by point; in step S4, a hammer is used to strike the second group of striking points uniformly point by point.

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