Numerical control milling and detecting device for arc-shaped metal structural member

Abstract

The utility model discloses arc metal structural member numerical control milling and detection device belongs to mechanical processing technical field, include: frock base body, frock base body is rectangular block structure, frock base body side surface processing has with arc metal structural member outer arc surface complete adaptation arc reverse cutting external shape surface, still being provided with three circular precision holes of penetration in frock base body, positioning device, positioning device includes three with precision hole cooperation's positioning pin, pressing device, pressing device includes special pressing plate and bolt, and the through -hole is seted up in the middle part of special pressing plate, and the arc shape of special pressing plate side wall processing has with arc metal structural member surface adaptation's arc shape and is pasted surface, and the through -hole of special pressing plate is set up in order after the threaded connection of bolt rod body with frock base body on the preset threaded hole of screwing. Solveed because of lacking the uniform clamping reference of with workpiece outer arc surface adaptation, positioning structure is unstable and workpiece and frock are not close, lead to clamping positioning deviation, cause workpiece wall thickness to be out of tolerance, and the technical problem such as low one time of exchange and check qualified rate.

Description

Technical Field

[0001] This utility model belongs to the field of mechanical processing technology, specifically relating to a CNC milling and inspection device for arc-shaped metal structural parts. Background Technology

[0002] In the field of aircraft manufacturing, the arc-shaped metal structural components used in the flap area are key components to ensure the aerodynamic performance of the aircraft. These parts are usually made of 40CrNiMoA molded parts, with large dimensions of 1400mm in length, 300mm in width, and 70mm in height. They also have strict requirements for machining accuracy. Not only must the wall thickness of the arc-shaped part be controlled within the tolerance range of 7±0.03mm, and the surface finish of the working surface must reach Ra1.6, but it must also meet the design condition that "when the theoretical outline profile is ≤0.05mm relative to the reference when the free state after machining is completed or when a single force of 2.28kg is applied at intervals of at least 305mm".

[0003] Currently, these types of curved metal structural parts are mainly produced using traditional CNC machining equipment. However, in actual manufacturing processes, existing equipment has many technical defects, resulting in a first-pass yield rate of only about 60%, which seriously restricts production efficiency and product quality. First, the existing machining equipment has an unreasonable selection of clamping and positioning references. It does not use the critical arc surface of the workpiece as a unified reference and lacks the function to check the deformation of the arc part of the workpiece after clamping. The positioning accuracy can only be maintained at about 0.05mm. After the workpiece is clamped, the positioning deviation is prone to cause the wall thickness to exceed the tolerance after milling according to the CNC program, and some workpieces are directly scrapped. Second, during the machining of the arc part of the workpiece, the existing equipment cannot achieve complete contact between the workpiece and the tooling surface, resulting in insufficient machining rigidity and easy generation of chirping marks during milling. In order to meet the surface finish requirements, manual polishing by a fitter is required. However, manual polishing is difficult to control the wall thickness accurately. Often, due to over-polishing or uneven polishing, the wall thickness dimension exceeds the tolerance by 7±0.03mm. Third, given the characteristics of high internal stress in workpiece materials and the tendency to produce slight deformations after processing, existing testing methods cannot meet the force application conditions required by the design. Conventional use of coordinate measuring machines to measure points on the workpiece in a free state cannot simulate the testing environment of "applying a force of 2.28 kg every ≥305 mm", resulting in some points having out-of-tolerance profiles, which in turn leads to the workpiece being misjudged and scrapped. At the same time, coordinate measuring machine point measurement is cumbersome and has low testing efficiency, further extending the workpiece manufacturing cycle.

[0004] In summary, existing CNC machining and inspection technologies for curved metal structural parts suffer from problems such as poor clamping and positioning accuracy, poor machining surface quality, low inspection efficiency, and low pass rate. There is an urgent need for an integrated device that can balance precise positioning, stable machining, and convenient inspection to solve the above-mentioned technical pain points. Utility Model Content

[0005] The purpose of this utility model is to provide a CNC milling and inspection device for arc-shaped metal structural parts, which solves the technical problems of existing milling and inspection devices, such as the lack of a unified clamping datum adapted to the outer arc surface of the workpiece, unstable positioning structure, and poor fit between the workpiece and the tooling, resulting in large clamping and positioning deviations, which in turn cause the workpiece wall thickness to exceed the tolerance and the first-pass inspection rate to be low.

[0006] The technical solution adopted in this utility model is a CNC milling and inspection device for arc-shaped metal structural parts, comprising: The tooling base is a rectangular block structure. The side of the tooling base is machined with an arc-shaped reverse tangent surface that is perfectly adapted to the outer arc surface of the arc-shaped metal structure. Three circular precision holes are also opened through the tooling base. The positioning device includes three positioning pins that mate with precision holes; The clamping device includes a special pressure plate and bolts. The special pressure plate has a through hole in the middle and an arc-shaped contact surface that is adapted to the surface of the arc-shaped metal structure on its side wall. The bolt shank passes through the through hole of the special pressure plate and is threaded into the threaded hole on the tooling base.

[0007] The features of this utility model also include: Along the edge area of ​​its arc-shaped reverse tangential surface, the tooling base is provided with a U-shaped auxiliary notch for measuring workpiece wall thickness. The depth and width of the auxiliary notch are adapted to allow the measuring end of a micrometer to extend into it, and the opening of the auxiliary notch faces the outside of the arc-shaped reverse tangential surface.

[0008] The diameter of the locating pin is consistent with the diameter of the precision hole in the tooling base. The locating pin is interference-fitted with the corresponding precision hole in the tooling base. The length of the locating pin is greater than the thickness of the tooling base. The top of the locating pin extends out of the arc-shaped reverse tangent surface of the tooling base.

[0009] The bolt head diameter is larger than the diameter of the circular through hole on the special pressure plate. When the bolt is tightened, the lower surface of its head fits tightly against the upper surface of the special pressure plate, thereby driving the arc-shaped contact surface of the special pressure plate to press tightly against the surface of the arc-shaped metal structure.

[0010] The clamping device also includes a feeler gauge and a torque wrench; the feeler gauge is a thin rectangular structure with a thickness of 0.02mm, and the feeler gauge is adapted to be inserted into the gap between the theoretical outer surface of the arc-shaped metal structure and the arc-shaped reverse tangent outer surface of the tooling base; the torque wrench is a sleeve-type structure, and the inner hole size of the torque wrench sleeve is adapted to the outer size of the bolt head.

[0011] Along the length of the arc-shaped reverse tangent outer surface of the tooling base, the pre-set threaded holes on the tooling base are linearly distributed.

[0012] The locating pins include locating pin a, locating pin b, and locating pin c, which are arranged in a triangular pattern on the tooling base. Locating pin a and locating pin b are symmetrically positioned on the left and right sides of one end of the tooling base along its length, while locating pin c is positioned in the middle of the other end of the tooling base along its length. The distribution structure of locating pins a, b, and c is adapted to fit the locating holes of the arc-shaped metal structure after it is rotated 180°, so that the locating holes of the arc-shaped metal structure correspond to and engage with locating pins a, b, and c one by one.

[0013] The length of the locating pin extending beyond the arc-shaped reverse tangent surface of the tooling base is adapted to the depth dimension of the locating hole of the arc-shaped metal structural component.

[0014] The beneficial effects of this utility model are: This invention uses the arc-shaped reverse tangent surface of the tooling base as a unified reference, and employs triangularly distributed locating pins a, b, and c that are interference-fitted with the base, improving the positioning accuracy from the traditional 0.05mm to 0.01mm. Combined with the uniform clamping of bolts and a special pressure plate, this ensures a tight fit between the workpiece and the base, allowing the workpiece wall thickness to be precisely controlled within a tolerance of 7±0.03mm. The first-pass yield rate increases from 60% to 100%, completely avoiding scrap due to clamping deviations. Simultaneously, the fully fitted structure of the workpiece and tooling significantly enhances machining rigidity, eliminates milling chatter marks, and achieves a surface finish of Ra1.6 on the working surface, reducing the amount of manual grinding by 70% and avoiding wall thickness deviations caused by manual grinding. The U-shaped workpiece wall thickness at the edge of the tooling base... The measuring auxiliary notch can be directly inserted into the micrometer for inspection. Combined with a constant force wrench that can simulate "applying a single force of 2.28 kg every >305 mm" and a 0.02 mm feeler gauge, it replaces the cumbersome three-coordinate measuring machine for point measurement, improving inspection efficiency by more than 50% and avoiding misjudgments and scrapping due to free state measurement. Moreover, the triangular distribution of the locating pins supports secondary positioning after the workpiece is rotated 180°. The device integrates milling clamping and arc surface inspection functions, eliminating the need for frequent tooling changes and shortening the workpiece manufacturing cycle by about 15%. In addition, the core components use conventional metal materials and mature processing technology, with a simple and reliable structure. Long-term use can significantly reduce the overall manufacturing cost by reducing the scrap rate and labor costs. It has outstanding practicality and economy in the field of production of arc-shaped metal structural parts for aircraft flaps. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the CNC milling and inspection device for arc-shaped metal structural parts of this utility model; Figure 2 This is a schematic diagram illustrating the use of the CNC milling and inspection device for arc-shaped metal structural parts according to this utility model.

[0016] In the figure, 1. Tooling base, 2. Locating pin a, 3. Locating pin b, 4. Locating pin c, 5. Special pressure plate, 6. Bolt, 7. Auxiliary notch for measuring workpiece wall thickness, 8. Workpiece. Detailed Implementation

[0017] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] Example 1 like Figure 1 and Figure 2 As shown, the CNC milling and inspection device for arc-shaped metal structural parts disclosed in this embodiment includes: Tooling base 1 is a rectangular block structure. The side of tooling base 1 is machined with an arc-shaped reverse tangent surface that is completely adapted to the outer arc surface of the arc-shaped metal structure (workpiece 8). Three circular precision holes are also opened through the tooling base 1. The positioning device includes three positioning pins that mate with precision holes; The clamping device includes a special pressure plate 5 and a bolt 6. The special pressure plate 5 has a through hole in the middle and an arc-shaped contact surface that is adapted to the surface of the arc-shaped metal structure on the side wall. The bolt 6 passes through the through hole of the special pressure plate 5 and is threaded into the threaded hole on the tooling base 1.

[0019] The CNC milling and inspection device for arc-shaped metal structural parts disclosed in this embodiment uses a rectangular block structure made of 45# steel as its tooling base 1. The dimensions can be determined according to the specifications of the workpiece 8 to be processed (e.g., when the length of workpiece 8 is 1400mm, the base length is set to 1500mm, the width to 350mm, and the thickness to 50mm). The side of the base along its length direction is machined with an arc-shaped reverse tangent outer surface that is completely consistent with the radius of curvature and arc length of the outer arc surface of workpiece 8 (after machining, it is calibrated with a coordinate measuring machine, and the arc surface error is ≤0.01mm). Three through-holes with diameters adapted to the positioning pins are also provided on the base. The three precision holes (e.g., when the locating pin diameter is 8mm, the hole diameter is 8mm, tolerance grade H7) are arranged in a triangle (two are located at one end along the length of the base body, 200mm apart, and the third is located in the middle of the other end, 1000mm away from the first two holes). The three locating pins of the positioning device are made of 40Cr cylindrical rods (8mm diameter, 60mm length), which are press-fitted into the three precision holes of the base body using an H7 / u6 interference fit. (After assembly, the perpendicularity is checked with a dial indicator, and the error is ≤0.02mm / m). The locating pin extends 10mm beyond the arc-shaped reverse tangent surface of the base body, and the extension length matches the depth of the locating hole of workpiece 8 (e.g., 8mm). The special pressure plate 5 of the clamping device is made of 65Mn spring steel and is a long strip structure of 250mm×50mm×8mm. A circular through hole with a diameter of 10mm (slightly larger than the bolt shank diameter) is opened in the middle. The inner side wall facing workpiece 8 is machined with an arc-shaped contact surface that matches the curvature of the outer arc surface of workpiece 8. The bolt 6 is an M8×30, 8.8 grade cylindrical head hexagonal bolt. During assembly, the outer arc surface of workpiece 8 is first placed against the base body. The workpiece 8 has an arc-shaped reverse-cut outer surface. The positioning holes of the workpiece 8 are fitted onto the three positioning pins. Then, the arc-shaped contact surface of the special pressure plate 5 is attached to the surface of the workpiece 8, so that the through hole of the pressure plate is aligned with the preset threaded hole of the base. Finally, the bolt 6 is threaded through the through hole of the pressure plate and tightened into the threaded hole of the base (tightening torque 20 N•m). The device can then be fixed on the CNC milling machine table to mill the inner arc surface or groove of the workpiece 8. After processing, there is no need to disassemble the workpiece 8. The accuracy can be directly tested based on the arc-shaped reverse-cut outer surface of the base. Those skilled in the art can implement this solution based on the above-mentioned materials, dimensions, and assembly parameters.

[0020] Example 2 Based on Example 1, a U-shaped auxiliary notch 7 for measuring the wall thickness of workpiece 8 is also provided on the edge area of ​​the tooling base 1 along its arc-shaped reverse tangent outer surface. The depth and width of the auxiliary notch 7 for measuring the wall thickness of workpiece 8 are adapted to the insertion of the measuring end of a micrometer, and the opening of the auxiliary notch 7 for measuring the wall thickness of workpiece 8 faces the outside of the arc-shaped reverse tangent outer surface.

[0021] Based on the tooling base 1 structure of Embodiment 1, this embodiment further processes a U-shaped auxiliary notch 7 for measuring the wall thickness of the workpiece 8 along the edge region of the arc-shaped reverse tangent outer surface of the tooling base 1. Specific implementation details are as follows: The notch opening position needs to be 10-15mm away from the edge of the arc-shaped reverse tangent outer surface (to avoid weakening the base strength and ensure accurate alignment with the workpiece 8 wall thickness detection position); the opening width of the U-shaped structure is set to 8-10mm, and the bottom inner radius is set to 2-3mm (to adapt to the shape of common micrometer measuring ends and prevent the measuring end from getting stuck); the depth of the notch is set to 12-15mm (greater than the effective length of a conventional micrometer measuring end, ensuring that the measuring end can fully extend into and contact the inner wall of the workpiece 8); the width is set to... The diameter is set to 4-6mm (1-2mm larger than the diameter of the micrometer measuring end to allow for operating space and avoid interference between the measuring end and the side wall of the notch). The machining accuracy of the notch must meet the following requirements: width tolerance ±0.1mm, depth tolerance ±0.1mm, and surface roughness Ra3.2 (machined in one step on a CNC milling machine using an end mill to remove burrs and prevent scratching of workpiece 8 or the micrometer). The notch opening faces the outer side of the arc-shaped reverse tangent surface (i.e., the side away from the contact area of ​​workpiece 8), so that the operator can hold the micrometer from the outside of the base, insert the measuring end into the notch along the opening, and make the two measuring surfaces of the micrometer contact the inner and outer walls of workpiece 8 respectively, and directly read the wall thickness value to check whether it meets the requirement of 7±0.03mm. In this embodiment, the other structures of the tooling base 1 (such as rectangular block size, arc-shaped reverse tangent surface accuracy, and circular accuracy hole parameters) and the structure and assembly method of the positioning device and clamping device are completely consistent with those of Embodiment 1. Based on Embodiment 1, those skilled in the art can complete the processing of the tooling base 1 according to the above-mentioned notch size, processing method and position requirements, so as to realize the function of conveniently detecting the wall thickness without disassembling the workpiece 8 after processing.

[0022] Example 3 Based on Example 1, the diameter of the locating pin is consistent with the diameter of the precision hole in the tooling base 1. The locating pin is interference-fitted with the corresponding precision hole in the tooling base 1. The length of the locating pin is greater than the thickness of the tooling base 1. The top of the locating pin extends out of the arc-shaped reverse tangent surface of the tooling base 1.

[0023] This embodiment, based on embodiment 1, further clarifies the dimensional adaptation relationship, fitting method, and length parameters of the locating pin and the precision hole of the tooling base 1. Specific implementation details are as follows: The diameter of the locating pin shaft and the diameter of the precision hole in the tooling base 1 are set to the same specification (e.g., both 8mm, which can be adjusted according to the size of the locating hole in the workpiece 8 to be processed; for example, this specification is used when the diameter of the locating hole in workpiece 8 is 8mm). The tolerance grade of the locating pin shaft is h6 (ensuring outer diameter accuracy and reducing fitting clearance), and the tolerance grade of the precision hole in the tooling base 1 is H7 (the inner hole accuracy matches the pin body, providing a basis for interference fit), ensuring that the two dimensions are completely consistent and avoiding loosening or assembly difficulties due to dimensional deviations. The two adopt an interference fit tolerance of H7 / u6 (this tolerance grade is suitable for positioning scenarios requiring a firm connection and without relative displacement). During assembly, 10-15k... The manual press of N presses the locating pin vertically into the precision hole. During the pressing process, a dial indicator is used to monitor the verticality of the locating pin in real time to ensure that the verticality error between the axis of the locating pin and the top surface of the fixture base is ≤0.02mm / m after pressing (to prevent the locating pin from tilting and causing the workpiece 8 to shift during clamping). After pressing, check the fit between the locating pin and the precision hole to ensure that there is no gap or looseness. The length of the locating pin is determined according to the thickness of the fixture base. For example, when the thickness of the fixture base is 50mm, the length of the locating pin is set to 60mm. The length of the pin is 10mm longer than the thickness of the base, so that the top of the locating pin extends 10mm beyond the arc-shaped reverse tangent surface of the fixture base. The extension length must be adapted to the depth of the locating hole of the workpiece 8 (for example, when the depth of the locating hole of the workpiece 8 is 8mm, the extension length of 10mm can ensure that the locating hole is completely fitted on the locating pin, and after fitting, the bottom surface of the workpiece 8 can be tightly fitted with the arc-shaped reverse tangent surface without any gaps). In this embodiment, the structure and assembly method of other structures of the tooling base (rectangular block size, arc-shaped reverse tangent surface accuracy), clamping device (special pressure plate, bolt) are completely consistent with those of Embodiment 1. Those skilled in the art can process the positioning pin according to the above diameter specifications, fit tolerances, assembly parameters and pin length requirements and complete the assembly with the tooling base to achieve accurate positioning of workpiece 8 and avoid processing errors caused by clamping offset.

[0024] Example 4 Based on Example 1, the diameter of the bolt head is larger than the diameter of the circular through hole on the special pressure plate. When the bolt is tightened, the lower surface of its head is tightly fitted with the upper surface of the special pressure plate, so as to drive the arc-shaped contact surface of the special pressure plate to press and fit tightly with the surface of the arc-shaped metal structure.

[0025] This embodiment, based on Embodiment 1, further clarifies the dimensional fit between the bolt and the special pressure plate and the clamping effect. Specific implementation details are as follows: M8 cylindrical head hexagonal bolts are selected, with a head diameter of 13mm (compliant with GB / T70.1 standard). The diameter of the circular through-hole in the center of the special pressure plate is 10mm (2mm larger than the bolt shank diameter, facilitating bolt insertion and reserving assembly clearance), ensuring that the bolt head diameter (13mm) is larger than the through-hole diameter (10mm), forming a stepped clamping structure. When the bolt is tightened with a wrench, the bolt… The lower surface of the bolt head will completely fit against the upper surface of the special pressure plate (the fitting surface must be flat with a surface roughness of Ra6.3 to avoid uneven pressure due to poor contact). The axial force generated by the threaded connection drives the arc-shaped fitting surface of the special pressure plate (which has the same curvature as the surface of workpiece 8) to press against workpiece 8 until the arc-shaped fitting surface is completely fitted against the surface of the arc-shaped metal structure (fitting gap ≤0.02mm, which can be detected by feeler gauge). This firmly fixes workpiece 8 on the arc-shaped reverse tangential surface of the tooling base, preventing workpiece 8 from shifting or vibrating during processing. In this embodiment, the structure and assembly method of the tooling base and positioning device are the same as in embodiment 1. The material (65Mn spring steel), size (250mm×50mm×8mm), and accuracy of the arc-shaped fitting surface of the special pressure plate also remain unchanged. Those skilled in the art can implement the above-mentioned bolt head and through hole size difference (3mm) and assembly requirements to achieve stable pressing of workpiece 8 and ensure processing accuracy.

[0026] Example 5 Based on Example 1, the clamping device also includes a feeler gauge and a fixed-force wrench; the feeler gauge is a thin rectangular structure with a thickness of 0.02 mm, and the feeler gauge is adapted to be inserted into the gap between the theoretical outer surface of the arc-shaped metal structure and the arc-shaped reverse tangent outer surface of the tooling base; the fixed-force wrench is a sleeve-type structure, and the inner hole size of the fixed-force wrench sleeve is adapted to the outer size of the bolt head.

[0027] Based on Example 1, this embodiment adds a feeler gauge and a torque wrench to the clamping device. The specific structure and matching relationship are as follows: The feeler gauge is made of 65Mn spring steel in the form of a thin rectangular structure, with a length of 100mm, a width of 12mm, and a thickness of 0.02mm (tolerance ±0.001mm, meeting the accuracy testing requirements). Its edges are rounded (corner radius 0.1mm) to prevent scratching the surface of the workpiece 8. The feeler gauge is adapted to be inserted into the gap between the theoretical outer surface of the arc-shaped metal structure and the arc-shaped reverse tangent outer surface of the tooling base, and is used to test the tightness of the fit (if the feeler gauge cannot be inserted, it indicates that the gap is ≤0.02mm, which meets the accuracy requirements). The torque wrench has a socket-type structure with a regular hexagonal inner hole and a face-to-face dimension of 13mm (matching the face-to-face dimension of an M8 cylindrical head hexagon socket bolt). The wrench range is set to 0-50 N•m, and the tightening torque can be preset (e.g., 20 N•m). An audible alert will sound when the bolt is tightened to the preset torque, ensuring consistent tightening force on each bolt. In use, the bolt is first tightened to the preset torque using the torque wrench, causing the special pressure plate to press against the workpiece 8. Then, a feeler gauge is inserted into the arc-shaped gap between the workpiece 8 and the fixture base to determine the fit accuracy. In this embodiment, the structure and assembly method of the fixture base, positioning device, and other components of the clamping device (special pressure plate, bolts) are consistent with those in Embodiment 1. Those skilled in the art can implement this according to the feeler gauge dimensions, torque wrench specifications, and usage steps described above to achieve precise control of the clamping force on the workpiece 8 and quantitative detection of the fit gap.

[0028] Example 6 Based on Example 1, the pre-set threaded holes on the tooling base are linearly distributed along the length direction of the arc-shaped reverse tangent outer surface of the tooling base.

[0029] This embodiment, based on Embodiment 1, further clarifies the distribution of pre-set threaded holes on the tooling base. Specific implementation details are as follows: Along the length of the arc-shaped reverse tangential outer surface of the tooling base (i.e., consistent with the extension direction of the arc surface), the threaded holes are uniformly distributed in a straight line. The distribution baseline is parallel to the centerline of the arc-shaped reverse tangential outer surface (offset distance 20mm, located outside the arc surface to avoid interference with the contact area of ​​the workpiece 8); the number of threaded holes is determined according to the length of the arc-shaped reverse tangential outer surface. For example, when the length of the arc surface is 1400mm, a total of [number missing] threaded holes are set. Five threaded holes (including both ends) are provided, with a spacing of 350mm between adjacent threaded holes (greater than 305mm to meet the requirement of uniform clamping). The threaded hole specification is M8 (compatible with the bolt in Example 1), with a hole depth of 20mm (greater than the bolt shank screw-in length by 15mm to ensure connection strength). The axis of each threaded hole is perpendicular to the top surface of the tooling base (perpendicularity error ≤0.05mm / 100mm), and the hole position tolerance is ±0.1mm (machined by CNC milling machine coordinate programming to ensure correspondence with the through hole position of the special pressure plate). This linear distribution structure allows the bolt and the special pressure plate to apply clamping force evenly along the length of the workpiece 8, avoiding excessive local force that could cause deformation of the workpiece 8 or uneven fitting gap. In this embodiment, the structure and assembly method of other structures of the tooling base 1 (rectangular block size, arc-shaped reverse tangent surface accuracy, circular accuracy hole), positioning device and other components of the clamping device (special pressure plate, bolt) are consistent with those of embodiment 1. Those skilled in the art can complete the thread hole processing according to the above hole distribution benchmark, quantity, spacing and processing accuracy requirements to achieve uniform clamping of workpiece 8.

[0030] Example 7 Based on Example 1, the positioning pins include positioning pin a, positioning pin b, and positioning pin c, which are distributed in a triangular pattern on the tooling base 1. Positioning pin a and positioning pin b are symmetrically arranged on the left and right sides of one end of the tooling base 1 along its length, and positioning pin c is arranged in the middle of the other end of the tooling base 1 along its length. The distribution structure of positioning pins a, b, and c is adapted to fit the positioning holes of the arc-shaped metal structure after it is rotated 180°, so that the positioning holes of the arc-shaped metal structure are fitted into the positioning pins a, b, and c one by one.

[0031] This embodiment, based on Embodiment 1, further clarifies the specific composition of the locating pins and their distribution on the tooling base 1. Specific implementation details are as follows: The locating pins include locating pin a, locating pin b, and locating pin c. The material (40Cr), structure (cylindrical long rod), dimensions (e.g., rod diameter 8mm, rod length 60mm), and fit with the precision holes in the tooling base 1 (H7 / u6 interference fit) of these three are consistent with Embodiment 1. The tooling base 1 still adopts a rectangular block structure (e.g., length 1500mm, width 350mm, thickness 50mm). The three locating pins are distributed in a triangular pattern on the base. Specifically, locating pin a and locating pin b are symmetrically positioned on the length of the tooling base 1. The two are symmetrically distributed along the width direction of the base body 1 at one end in the length direction (50mm from the starting point of the base body length), and are 50mm away from both sides of the base body width direction edge. Therefore, the distance between the positioning pin a and the positioning pin b is 250mm (350mm-50mm-50mm). The positioning pin c is set at the other end of the tooling base 1 in the length direction (50mm from the end point of the base body length), and is located at the center position in the width direction of the base body (175mm away from both sides of the width). At this time, the distance between the positioning pin c and the positioning pin a and positioning pin b in the length direction is 1400mm (1500mm-50mm-50mm), forming a stable triangular positioning structure. This distribution structure is adapted to the positioning requirements of curved metal structural parts after being rotated 180°: the three pre-set positioning holes on the workpiece 8 are also arranged in a triangle to match the positioning pins. When the workpiece 8 needs to be processed on the other side of the cavity and is rotated 180°, the positioning holes on the workpiece 8 that were originally close to positioning pins a and b will move to the side of positioning pin c, and the positioning holes that were originally close to positioning pin c will move to the side of positioning pins a and b. After the workpiece 8 is rotated, the position of the positioning holes can still be matched with the three positioning pins one by one, and secondary positioning can be completed without adjusting the tooling. In this embodiment, the arc-shaped reverse tangent outer surface, precision holes and clamping device structure and assembly method of the tooling base 1 are the same as those in embodiment 1. Those skilled in the art can process the precision holes and assemble the positioning pins according to the above positioning pin distribution position parameters to achieve accurate positioning of the workpiece 8 when processing the front and back sides.

[0032] Example 8 Based on Example 1, the length of the locating pin extending out of the arc-shaped reverse tangent outer surface of the tooling base 1 is adapted to the depth dimension of the locating hole of the arc-shaped metal structure.

[0033] Based on Example 1, this embodiment further clarifies the compatibility between the "length of the positioning pin extending out of the arc-shaped reverse tangential surface of the tooling base 1" and the "depth of the positioning hole of the arc-shaped metal structural component," ensuring the stability and fit of the workpiece 8 during positioning. Specific implementation details are as follows: First, the depth parameters of the positioning hole of the arc-shaped metal structure need to be determined. According to the design requirements of the workpiece 8 to be processed (such as the wall thickness of workpiece 8 is 7mm and the overall height is 70mm), the depth of the positioning hole of workpiece 8 is usually set to 8-10mm (in conventional design, the depth of the positioning hole needs to meet the requirement of "stable positioning and not penetrating workpiece 8" to avoid weakening the strength of workpiece 8). This embodiment takes the positioning hole depth of workpiece 8 as 8mm as an example for explanation.

[0034] Secondly, considering the thickness parameters of the tooling base 1 in Example 1 (e.g., base thickness 50mm), the total length of the locating pin needs to be calculated according to the formula "extension length = total length of locating pin - thickness of tooling base 1": In order to make the length of the locating pin extending out of the arc-shaped reverse tangential surface match the 8mm deep locating hole, the total length of the locating pin is set to 60mm (50mm base thickness + 10mm extension length), that is, the length of the locating pin extending out of the arc-shaped reverse tangential surface is 10mm - this extension length is 2mm greater than the depth of the locating hole of the workpiece 8, which can ensure that the locating hole of the workpiece 8 is completely fitted on the locating pin (fitting depth 8mm, consistent with the depth of the locating hole), and also avoid the locating pin extending too long, causing interference at the top of the workpiece 8 (the remaining 2mm extension length is outside the locating hole and does not affect other structures of the workpiece 8).

[0035] If the depth of the positioning hole of workpiece 8 is adjusted (e.g., changed to 10mm), the total length of the positioning pin needs to be adjusted simultaneously: when the thickness of the tooling base 1 is still 50mm, the total length of the positioning pin is set to 62mm, so that the extension length is 12mm (2mm larger than the 10mm positioning hole depth). The principle of "extension length is 1-2mm larger than the positioning hole depth" is maintained to ensure that there is no looseness after the positioning hole is fitted, and that the bottom surface of workpiece 8 can fit tightly with the arc-shaped reverse tangent outer surface of the tooling base 1 (fitting gap ≤0.02mm, which can be detected by a 0.02mm feeler gauge).

[0036] In this embodiment, the material of the locating pin (40Cr), the fitting method (interference fit) with the precision hole of the tooling base 1, the precision of the arc-shaped reverse tangential surface of the tooling base 1, and the structure of the clamping device are all completely consistent with those in Embodiment 1. Those skilled in the art can determine the total length of the locating pin according to the formula "extension length = locating hole depth + 1-2mm" based on the actual depth of the locating hole in the workpiece 8, thereby completing the machining and assembly of the locating pin and achieving precise positioning of the workpiece 8.

[0037] The working process and working principle of this utility model are as follows: During operation, first, the outer arc surface of the arc-shaped metal structural component is fitted onto the arc-shaped reverse tangential surface of the fixture base 1, so that the positioning holes on the workpiece 8 are correspondingly fitted onto the triangularly distributed positioning pins a, b, and c (the positioning pins are fixed to the fixture base 1 by interference fit, and their extension length matches the depth of the positioning holes on the workpiece 8, ensuring that the bottom surface of the workpiece 8 is tightly fitted to the arc-shaped reverse tangential surface); then, the arc-shaped fitting surface of the special pressure plate is fitted onto the surface of the workpiece 8, so that the through hole of the pressure plate is aligned with the threaded holes linearly distributed along the length direction of the arc-shaped reverse tangential surface on the fixture base 1, and the bolts are tightened with a fixed torque wrench to a preset torque. The clamping force is formed by the dimensional difference between the bolt head and the through hole of the pressure plate, which drives the pressure plate to firmly fix the workpiece 8 onto the fixture base 1 (through 0 (Use a 0.02mm feeler gauge to check the fit gap between workpiece 8 and the base to ensure there is no looseness); after fixing, clamp the entire device onto a CNC milling machine, and mill workpiece 8 using the arc-shaped reverse tangent outer surface of the fixture base 1 as a reference; during or after processing, the wall thickness of workpiece 8 can be measured using the auxiliary notch 7 on the edge of the U-shaped workpiece 8, and a micrometer can be inserted to check the wall thickness of workpiece 8; if it is necessary to process the other side of workpiece 8, rotate workpiece 8 180°, and its positioning holes can still be matched with the triangularly distributed positioning pins one by one. Repeat the above clamping steps to continue processing. The entire device achieves stable clamping, precise processing and convenient inspection of arc-shaped metal structural parts through the precise positioning of positioning pins, uniform clamping of bolts and pressure plates and precision control of auxiliary tools.

[0038] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0039] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0040] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A numerical control milling and detecting device for arc-shaped metal structural parts, characterized in that, include: Tooling base (1) is a rectangular block structure. The side of the tooling base (1) is machined with an arc-shaped reverse tangent surface that is perfectly adapted to the outer arc surface of the arc-shaped metal structure. Three circular precision holes are also opened through the tooling base (1). The positioning device includes three positioning pins that mate with precision holes; The clamping device includes a special pressure plate (5) and a bolt (6). The special pressure plate (5) has a through hole in the middle and the side wall of the special pressure plate (5) is machined with an arc-shaped contact surface that is adapted to the surface of the arc-shaped metal structure. The bolt (6) passes through the through hole of the special pressure plate (5) and is threaded to the threaded hole on the tooling base (1).

2. The device according to claim 1, wherein, Along the edge region of its arc-shaped reverse tangent outer surface, the tooling base (1) is provided with a U-shaped auxiliary notch (7) for measuring workpiece wall thickness. The depth and width of the auxiliary notch (7) are adapted to allow the measuring end of a micrometer to extend into it, and the opening of the auxiliary notch (7) faces the outside of the arc-shaped reverse tangent outer surface.

3. The CNC milling and inspection device for arc-shaped metal structural parts according to claim 1, characterized in that, The diameter of the locating pin is consistent with the diameter of the precision hole of the tooling base (1). The locating pin is interference-fitted with the corresponding precision hole of the tooling base (1). The length of the locating pin is greater than the thickness of the tooling base (1). The top of the locating pin extends out of the arc-shaped reverse tangent surface of the tooling base (1).

4. The CNC milling and inspection device for arc-shaped metal structural parts according to claim 1, characterized in that, The head diameter of the bolt (6) is larger than the diameter of the circular through hole on the special pressure plate (5). When the bolt (6) is tightened, the lower surface of its head is tightly fitted with the upper surface of the special pressure plate (5) so as to drive the arc-shaped contact surface of the special pressure plate (5) to press and fit tightly with the surface of the arc-shaped metal structure.

5. The CNC milling and inspection device for arc-shaped metal structural parts according to claim 1, characterized in that, The clamping device also includes a feeler gauge and a fixed-force wrench; the feeler gauge is a thin rectangular structure with a thickness of 0.02 mm, and the feeler gauge is adapted to be inserted into the gap between the theoretical outer surface of the arc-shaped metal structure and the arc-shaped reverse tangent outer surface of the tooling base (1); the fixed-force wrench is a sleeve-type structure, and the inner hole size of the fixed-force wrench sleeve is adapted to the outer size of the bolt (6) head.

6. The CNC milling and inspection device for arc-shaped metal structural parts according to claim 1, characterized in that, Along the length of the arc-shaped reverse tangent outer surface of the tooling base (1), the pre-set threaded holes on the tooling base (1) are linearly distributed.

7. The CNC milling and inspection device for arc-shaped metal structural parts according to claim 1, characterized in that, The positioning pins include positioning pin a (2), positioning pin b (3), and positioning pin c (4). Positioning pins a (2), positioning pin b (3), and positioning pin c (4) are distributed in a triangular pattern on the tooling base (1). Positioning pin a (2) and positioning pin b (3) are symmetrically arranged on the left and right sides of one end of the tooling base (1) along the length direction, and positioning pin c (4) is arranged in the middle of the other end of the tooling base (1) along the length direction. The distribution structure of positioning pins a (2), positioning pin b (3), and positioning pin c (4) is adapted to the arc-shaped metal structure. After the arc-shaped metal structure is rotated 180°, the positioning holes of the arc-shaped metal structure are fitted one-to-one with positioning pins a (2), positioning pin b (3), and positioning pin c (4).

8. The CNC milling and inspection device for arc-shaped metal structural parts according to claim 1, characterized in that, The length of the positioning pin extending out of the arc-shaped reverse tangent surface of the tooling base (1) is adapted to the depth dimension of the positioning hole of the arc-shaped metal structure.

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