A processing method of a semi-circular reference of a thin-walled sector structure part and a bushing

Abstract

The application discloses a kind of thin-walled sector structure part semicircle reference processing method, bushing, method includes: based on the structure of part Formulation include heat control process route of shape control;Semi-finishing is carried out to part;After semi-finishing, the part is clamped using heat shape control special fixture, heat shape control processing is carried out, and preliminary control heat shape control after part is obtained;Finish machining fixture is installed on lathe and is aligned;After heat shape control, the part to be machined is clamped on the aligned finish machining fixture, and the part to be finished is fixed by aligning inner hole and applying floating support;Install machine clamp tool and select finish machining blade, set parameter;Semi-circular reference plane of part is carried out finish machining cutting, and the combined tool path of inside-out and outside-in is used to tool path, and processing is completed.The application effectively controls the deformation amount before part finish machining, enhances the clamping rigidity of semicircular weak place, makes machining semicircular reference plane positioning reliable, and improves the quality and efficiency of processing.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine manufacturing technology, specifically relating to a method for machining a semi-circular datum of a thin-walled fan-shaped structural part and a bushing. Background Technology

[0002] The front sealing bushing of the aero-engine main shaft is a core component of the aero-engine central transmission unit. It seals the front grates of the engine's three-point bearing housing, providing a runway for the grates. The bushing itself has a thin-walled fan-shaped structure, working in conjunction with the grates to seal the front bearing cavity. Simultaneously, four radially arranged boss holes connect to the bleed pipe to introduce high-pressure airflow and prevent lubricating oil leakage. Due to the component's structure and manufacturing process, this type of part has high technical requirements and is difficult to manufacture. Improving the machining level of the front bearing sealing bushing can effectively enhance the sealing effect of the front grates of the engine's three-point bearing housing, thereby reducing engine lubricating oil consumption and the safety risks caused by lubricating oil leakage, and ensuring engine quality and safety.

[0003] These types of parts are typically cast from ZTC4 titanium alloy and subjected to hot isostatic pressing and annealing. ZTC4 material boasts advantages such as high strength and good heat resistance, but it also exhibits significant resilience and susceptibility to deformation during machining. The semi-circular reference plane to be machined is particularly critical; its designed wall thickness is only 4mm, its width is 21.5mm, and it is supported by a fan-shaped thin-walled conical surface with a wall thickness of only 2mm and an angle of 45°. This weakly rigid structure means that the semi-circular reference plane is suspended during machining, and the cutting process is intermittent, making it highly susceptible to deformation due to cutting forces, clamping stress, and the release of residual stress within the material. Actual production data shows that the machining deformation in this process typically fluctuates between 0.7mm and 1mm, severely restricting the machining pass rate and production consistency, becoming a manufacturing bottleneck for improving the overall quality and reliability of the engine.

[0004] As an improvement, Chinese Patent CN103624497B discloses a machining method for large-radius thin-walled semi-circular annular parts, addressing the deformation problem during machining of thin-walled parts. This method targets planar large-radius parts and controls deformation through specific clamping and cutting strategies. However, the machining method for this part structure fails to adequately consider the unique rigidity weakness of the semi-circular plane supported by an extremely thin fan-shaped conical surface under suspended and intermittent cutting conditions, thus limiting its direct applicability. Chinese Patent CN103143885B discloses a machining method for split-type thin-walled parts, applicable to split structures, with relatively low machining difficulty and challenges. Existing technologies generally lack systematic deformation control process designs for such specific structures during machining.

[0005] In summary, the current process for manufacturing the front sealing bushing of the main shaft of aero-engines lacks an effective step for actively eliminating internal stress and actively correcting the shape of the part after semi-finishing, resulting in significant deformation risks before finishing. Traditional fixture designs fail to address the extremely weak circumferential rigidity of the semi-circular reference plane, and the clamping points and supports are unreasonable, failing to provide sufficient local rigidity support for the part during cutting. In the finishing stage, the combined effects of springback of ZTC4 material and intermittent cutting are not effectively offset, making it difficult to simultaneously ensure processing efficiency and final forming accuracy. Summary of the Invention

[0006] This invention provides a machining method and bushing for a semi-circular datum of a thin-walled fan-shaped structural part. The purpose is to solve the problems in the current machining of the front sealing bushing of the spindle, which lacks active elimination of internal stress and active shape correction, resulting in potential deformation of the part; unreasonable clamping points and supports, which cannot provide sufficient local rigid support; and the failure to effectively counteract the effects of material springback and intermittent cutting, making it difficult to guarantee machining efficiency and product accuracy.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a method for machining a semi-circular datum for a thin-walled fan-shaped structural part, comprising the following steps:

[0009] S1. Perform process analysis on the parts to be processed, and formulate a process route that includes thermal correction control based on the structural rigidity and material resilience of the parts to be processed.

[0010] S2. Perform semi-finishing on the parts to be processed according to the process route including thermal calibration control, and then obtain the semi-finished parts to be processed.

[0011] S3. Use a special hot-calibration fixture to clamp the semi-finished parts and perform hot-calibration treatment to obtain the deformation amount and obtain the preliminarily controlled hot-calibrated parts to be processed.

[0012] S4. Install the finishing fixture on the lathe and align it. The finishing fixture has an auxiliary support structure that enhances the clamping rigidity at the thin-walled semi-circular reference plane. After heat correction, clamp the part to be machined on the aligned finishing fixture. Fix the part to be machined by aligning the inner hole and applying floating support.

[0013] S5. Install the clamped cutting tool and select the finishing insert. Set the parameters of spindle speed, feed rate and depth of cut. Perform finishing cutting on the thin-walled semi-circular reference plane of the part to be finished, using a combination of inside-out and outside-in tool paths to complete the machining of the semi-circular reference of the thin-walled fan-shaped structure part.

[0014] In some implementations, in S1, the part to be processed includes a thin-walled fan-shaped structural part, which is a front sealing bushing of the main shaft of an aero-engine, made of ZTC4, and subjected to hot isostatic pressing and annealing treatment.

[0015] Furthermore, in S1, the thin-walled semicircular reference plane of the thin-walled fan-shaped structural part is supported by a fan-shaped conical surface.

[0016] In some implementations, in S3, the material of the heat-calibrating special fixture is 1Cr18Ni9T.

[0017] In some implementations, step S4, mounting the finishing fixture on the lathe and aligning it, specifically includes:

[0018] Use bolts to install the finishing fixture on the lathe faceplate, align the reference circle of the finishing fixture so that the runout is no more than 0.02mm, and then tighten it.

[0019] In some implementations, in step S3, clamping the heat-calibrated part to be processed onto the aligned finishing fixture specifically includes:

[0020] Position the part on the small end face after heat calibration, install it on the positioning surface of the precision machining fixture, align the inner hole of the part after heat calibration so that the runout is no more than 0.02mm, press the mounting edge with a pressure plate; set up floating support, control the oscillation value of the gauge to be within 0.005mm, and then tighten the stop nut.

[0021] Furthermore, in S3, the body material of the finishing fixture is 45 steel, and the floating support is carried out using the pressure gauge method.

[0022] In some implementations, in S5, the spindle speed is set to 40 r / min, the feed rate is set to 0.04 mm / r, and the depth of cut is set to 0.03 to 0.15 mm.

[0023] In some implementations, in S5, the tool holder of the indexable lathe tool is SVLBL 2525-M16, and the finishing insert is VBMT160402 F1 CP500.

[0024] The present invention also provides a bushing, wherein the thin-walled semi-circular reference plane of the bushing is formed by the above-mentioned machining method of the semi-circular reference of the thin-walled fan-shaped structural part.

[0025] Compared with the prior art, the present invention provides a machining method for a semi-circular datum of a thin-walled fan-shaped structural part and a bushing, which has the following advantages:

[0026] This invention discloses a machining method for a semi-circular datum of a thin-walled fan-shaped structural part. Based on the part's structural characteristics and material properties, a reasonable process route is formulated, suitable fixtures and cutting tools are manufactured, and appropriate cutting parameters are selected. This method improves upon problems such as deformation, tool deflection, tool vibration, and low machining efficiency encountered in machining the thin-walled semi-circular datum plane of the engine spindle front sealing bushing, thus meeting the machining requirements of the engine spindle front sealing bushing. This invention effectively controls the amount of deformation during semi-finishing by controlling the hot-calibration process and designing a dedicated hot-calibration fixture. A dedicated fixture consisting of auxiliary supports, a fixture base, and a pressure plate is designed and manufactured. By increasing the number of auxiliary support points, the clamping rigidity of the weak points of the semi-circle is enhanced, ensuring reliable positioning of the semi-circular datum plane. Using 30° rhomboid inserts, with separate roughing and finishing operations, and selecting reasonable machining paths and cutting parameters, the finishing quality and efficiency of the thin-walled semi-circular datum plane are improved. Attached Figure Description

[0027] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0028] Figure 1 This is a schematic diagram of the structure of the thin-walled semi-circular reference plane B of the spindle front sealing bushing in the machining method of the semi-circular reference of a thin-walled fan-shaped structural part according to the present invention.

[0029] Figure 2 This is a schematic diagram of the thermal calibration fixture used in the machining method of a semi-circular datum for a thin-walled fan-shaped structural part according to the present invention.

[0030] Figure 3 This is a schematic diagram of the finishing lathe fixture used in the machining method of a semi-circular datum for a thin-walled fan-shaped structural part according to the present invention.

[0031] Figure 4 This is a schematic diagram of the tool holder structure in the machining method of a semi-circular datum for a thin-walled fan-shaped structural part according to the present invention;

[0032] Figure 5 This is a schematic diagram of the blade structure in the machining method of a semi-circular datum for a thin-walled fan-shaped structural part according to the present invention;

[0033] Figure 6 This is a schematic diagram of the tool path in the machining method of a semi-circular datum for a thin-walled fan-shaped structural part according to the present invention;

[0034] Figure 7 This is a schematic diagram of another angle of the tool path in the machining method of a semi-circular datum for a thin-walled fan-shaped structural part according to the present invention.

[0035] Among them, 1. thin-walled semi-circular reference plane, 2. tool holder, 3. cutting tool. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0037] The theories or mechanisms described and disclosed in this invention, whether right or wrong, should not limit the scope of the invention in any way; that is, the contents of this invention can be implemented without being limited by any particular theory or mechanism.

[0038] In this invention, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be regarded as covering and specifically disclosing all possible secondary ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0039] In this invention, unless otherwise specified, the terms “comprising,” “including,” “containing,” “having,” or similar terms cover the meanings of “composed of” and “mainly composed of”. For example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a”.

[0040] In this invention, for the sake of brevity, not all possible combinations of the technical features in each embodiment or example are described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0041] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0042] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0043] How to provide a comprehensive method specifically for machining the semi-circular datum of such thin-walled fan-shaped structural parts, and systematically solve the machining deformation problem from multiple levels such as process route planning, special tooling design, and cutting process optimization, so as to meet the stringent manufacturing requirements of aero-engines for high-performance and high-reliability parts.

[0044] like Figures 1-7 As shown, the present invention provides a method for machining a semi-circular datum for a thin-walled fan-shaped structural part, comprising the following steps:

[0045] S1. Perform process analysis on the parts to be processed, and formulate a process route that includes thermal correction control based on the structural rigidity and material resilience of the parts to be processed.

[0046] S2. Perform semi-finishing on the parts to be processed according to the process route including thermal calibration control, and then obtain the semi-finished parts to be processed.

[0047] S3. Use a special hot-calibration fixture to clamp the semi-finished parts and perform hot-calibration treatment to obtain the deformation amount and obtain the preliminarily controlled hot-calibrated parts to be processed.

[0048] S4. Install the finishing fixture on the lathe and align it. The finishing fixture has the feature of an auxiliary support structure that enhances the clamping rigidity at the thin-walled semi-circular reference plane 1. Clamp the heat-corrected part to be machined on the aligned finishing fixture. Fix the part to be machined by aligning the inner hole and applying floating support.

[0049] S5. Install the clamped turning tool and select the finishing insert 3. Set the parameters of spindle speed, feed rate and depth of cut. Perform finishing cutting on the thin-walled semi-circular reference plane 1 of the part to be finished, and use a combination of inside-out and outside-in tool paths to complete the machining of the semi-circular reference of the thin-walled fan-shaped structure part.

[0050] This invention discloses a machining method for a semi-circular datum of a thin-walled fan-shaped structural part. Based on the structural rigidity and material resilience of the part, a process route incorporating thermal calibration control is established. Thermal calibration is pre-embedded into the process, providing a blank with more stable geometric dimensions and effectively controlled internal stress for subsequent machining. Semi-finishing prepares a part with suitable shape and allowance for the thermal calibration process. The thermal calibration step uses a dedicated fixture to apply correction to the semi-finished part under hot conditions, releasing and homogenizing the internal stress generated in the previous machining, actively correcting deformation caused by stress release and weakened rigidity, and obtaining a part with preliminary and effective control over deformation. This invention achieves ultra-precise positioning and enhanced local rigidity of the part by clamping the pre-stabilized thermally calibrated part in a finishing fixture and using precise alignment and floating support. The cutting parameters set in this invention balance the influence of cutting forces, employing a combination of inside-out and outside-in tool paths, which neutralizes cutting forces in opposite directions, suppressing tool deflection, vibration, and new deformations that may occur during cutting.

[0051] Furthermore, in the processing method of the present invention, the material of the thin-walled fan-shaped structural part is ZTC4 and is subjected to hot isostatic pressing and annealing treatment. It is designed for difficult-to-process materials with high resilience and easy to cause processing deformation. The thin-walled semi-circular reference plane 1 is supported by the fan-shaped conical surface.

[0052] Furthermore, the material of the special fixture for hot-calibration in this invention is 1Cr18Ni9T, which ensures that the fixture has good oxidation resistance, thermal stability, and thermal fatigue resistance under the high-temperature environment required for hot-calibration. It can maintain the stability of its shape and size for a long time, thus ensuring that the correction force applied to the part during hot-calibration is accurate and consistent, and that the correction effect is not affected by the deformation of the fixture itself, improving the reliability and repeatability of the hot-calibration process. The installation and alignment method of the finishing fixture, as well as the clamping and alignment method of the part on the fixture, ensures the installation accuracy of the finishing fixture itself on the machine tool, establishing a reliable process benchmark for the entire finishing process. It achieves accurate installation of the part on the precisely positioned fixture. Through the protection of the main positioning surface and auxiliary alignment benchmark, the positional accuracy of the part relative to the fixture and the machine tool spindle is ensured. Moreover, this invention, through a dynamically adjustable support method, can actively eliminate clamping deformation that may be caused by the part's own weight or small clamping force before final locking, achieving deformation control and enhancing the local rigidity of the part during machining. For thin-walled semi-circular areas, it suppresses tool deflection during cutting.

[0053] Furthermore, this invention features a spindle speed of 40 r / min, a feed rate of 0.04 mm / r, and a depth of cut of 0.03~0.15 mm. It provides a set of validated, optimized cutting parameters specifically for the ZTC4 material and its extremely weak rigidity structure. This allows for precise material removal and ultra-high precision surface forming, achieved based on deformation controlled by thermal straightening and fixture reinforcement. The tool holder 2 is model SVLBL 2525-M16, and the finishing insert 3 is model VBMT160402 F1 CP500. These parameters ensure stability in the cutting process and tool life while maintaining reasonable cutting parameters, thereby guaranteeing the stability and consistency of the final machining quality.

[0054] Specifically, the machining method for the semi-circular datum of the thin-walled fan-shaped structural part of the present invention is carried out by the following steps:

[0055] Process Analysis of the Thin-Walled Semicircular Reference Plane 1 of the Spindle Front Sealing Bushing: The spindle front sealing bushing is made of ZTC4, a Class II casting, hot isostatic pressing followed by annealing. The reference plane is a semicircular plane with a wall thickness of 4mm and a width of 21.5mm, supported by a fan-shaped conical surface with a wall thickness of 2mm and an angle of 45°. The part material is ZTC4, which has high elasticity. The semicircular reference plane is suspended during machining and undergoes intermittent cutting. The part itself has poor structural rigidity. By increasing thermal calibration, the deformation during semi-finishing is controlled. Simultaneously, through comparative experiments on fixtures, tools, and machining parameters in the finishing stage, a machining method suitable for the thin-walled semicircular reference plane of the aero-engine spindle front sealing bushing is developed.

[0056] Add a heat calibration process.

[0057] Specialized fixtures for making heat-calibrated models.

[0058] A lathe with a specification of Φ400×720 is selected to machine the thin-walled semi-circular reference plane 1.

[0059] A fixture for clamping a thin-walled semi-circular reference plane 1.

[0060] Select the machining tools used for machining the semi-circular reference plane.

[0061] Clamping and alignment of fixtures and parts.

[0062] Installation of clamped turning tools and replacement of inserts;

[0063] Cutting parameters and tool path for the semi-circular reference plane.

[0064] The present invention also provides a bushing, wherein the thin-walled semi-circular reference plane 1 of the bushing is formed by the above-mentioned machining method of the semi-circular reference of the thin-walled fan-shaped structural part.

[0065] The following detailed description of the machining method and bushing for a semi-circular datum of a thin-walled fan-shaped structural part according to the present invention will be provided through specific embodiments.

[0066] Machining method for the semi-circular datum of thin-walled fan-shaped structural parts:

[0067] A heat-adjusting process is added after semi-finishing;

[0068] like Figure 2 As shown, a special tooling for heat calibration is fabricated;

[0069] like Figure 3 As shown, a fixture is used in step 1 to fabricate a precision-machined thin-walled semi-circular reference plane.

[0070] like Figure 4 and Figure 5 As shown, prepare a clamped tool for finishing the thin-walled semi-circular reference plane 1;

[0071] Fixture clamping and alignment:

[0072] Install the fixture on the lathe faceplate with four bolts, align the reference circle by no more than 0.02mm, and tighten.

[0073] Part clamping and alignment:

[0074] Position the part using its small end face and install it on the lathe fixture positioning surface. Align the inner hole with a pressure plate that is no larger than 0.02mm to press the mounting edge. Use a pressure gauge to set the floating support, controlling the gauge swing value to be within 0.005mm. Then tighten the stop nut to prevent the floating support from loosening during rotation.

[0075] Cutting parameters and tool path for the semi-circular reference plane.

[0076] The finishing cutting parameters are determined as shown in Table 1 below.

[0077] Table 1 Machining cutting parameters

[0078]

[0079] like Figure 6 and Figure 7 As shown, the entry point is specified as a relatively rigid inclined surface, and the tool path is a combination of inside-out and outside-in, so that the cutting forces are canceled out in opposite directions, reducing the deformation of the part caused by the cutting forces. This completes the machining of the semi-circular datum of the thin-walled fan-shaped structure part.

[0080] Deformation of the thin-walled semi-circular reference plane 1 is checked to ensure that the machining of the part meets the preset requirements.

[0081] In summary, the present invention provides a machining method and bushing for a semi-circular datum of a thin-walled fan-shaped structural part. Through the synergistic effects of process analysis and prediction, semi-finishing preparation, active correction by thermal calibration, enhanced rigidity of special fixtures, and optimization of cutting parameters and paths, the inherent problems of deformation, vibration, and difficulty in ensuring accuracy in the machining of the semi-circular datum of a thin-walled fan-shaped structural part are improved. This invention achieves high-quality and stable machining of the semi-circular datum of a thin-walled fan-shaped structural part and has certain practical significance.

[0082] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Anyone skilled in the art can readily implement the present invention according to the description and above. Any modifications, alterations, or variations made based on the disclosed technical content are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A method for machining a semi-circular datum for a thin-walled fan-shaped structural part, characterized in that, Includes the following steps: S1. Perform process analysis on the parts to be processed, and formulate a process route that includes thermal correction control based on the structural rigidity and material resilience of the parts to be processed. S2. Perform semi-finishing on the parts to be processed according to the process route including thermal calibration control, and then obtain the semi-finished parts to be processed. S3. Use a special hot-calibration fixture to clamp the semi-finished parts and perform hot-calibration treatment to obtain the deformation amount and obtain the preliminarily controlled hot-calibrated parts to be processed. S4. Install the finishing fixture on the lathe and align it. The finishing fixture has an auxiliary support structure feature that enhances the clamping rigidity at the thin-walled semi-circular reference plane (1). After heat calibration, the part to be machined is clamped on the aligned finishing fixture. The part to be machined is fixed by aligning the inner hole and applying floating support. S5. Install the machine tool and select the finishing insert (3). Set the parameters of spindle speed, feed rate and depth of cut. Perform finishing cutting on the thin-walled semi-circular reference plane (1) of the part to be finished. Use a combination of inside-out and outside-in tool paths to complete the machining of the semi-circular reference of the thin-walled fan-shaped structure part.

2. The machining method for the semi-circular datum of the thin-walled fan-shaped structural part according to claim 1, characterized in that, In S1, the part to be processed includes a thin-walled fan-shaped structural part, which is a front sealing bushing of the main shaft of an aero-engine, made of ZTC4 material, and subjected to hot isostatic pressing and annealing treatment.

3. The machining method for the semi-circular datum of the thin-walled fan-shaped structural part according to claim 2, characterized in that, In S1, the thin-walled semi-circular reference plane (1) of the thin-walled fan-shaped structural part is supported by a fan-shaped conical surface.

4. The machining method for the semi-circular datum of the thin-walled fan-shaped structural part according to claim 1, characterized in that, In S3, the material of the heat-calibrated special fixture is 1Cr18Ni9T.

5. The machining method for the semi-circular datum of the thin-walled fan-shaped structural part according to claim 1, characterized in that, In step S4, mounting the finishing fixture onto the lathe and aligning it specifically includes: Use bolts to install the finishing fixture on the lathe faceplate, align the reference circle of the finishing fixture so that the runout is no more than 0.02mm, and then tighten it.

6. The machining method for the semi-circular datum of the thin-walled fan-shaped structural part according to claim 1, characterized in that, In step S3, clamping the heat-calibrated part to be processed onto the aligned finishing fixture specifically includes: Position the part on the small end face after heat calibration, install it on the positioning surface of the precision machining fixture, align the inner hole of the part after heat calibration so that the runout is no more than 0.02mm, press the mounting edge with a pressure plate; set up floating support, control the oscillation value of the gauge to be within 0.005mm, and then tighten the stop nut.

7. The machining method for the semi-circular datum of the thin-walled fan-shaped structural part according to claim 6, characterized in that, In S3, the body material of the finishing fixture is 45 steel, and the floating support is operated using a pressure gauge method.

8. The machining method for the semi-circular datum of the thin-walled fan-shaped structural part according to claim 1, characterized in that, In S5, the spindle speed is set to 40 r / min, the feed rate is set to 0.04 mm / r, and the depth of cut is set to 0.03 to 0.15 mm.

9. The machining method for the semi-circular datum of the thin-walled fan-shaped structural part according to claim 1, characterized in that, In S5, the tool holder (2) of the machine-clamped turning tool is model SVLBL 2525-M16, and the finishing insert (3) is model VBMT160402 F1CP500.

10. A bushing, characterized in that, The thin-walled semi-circular reference plane (1) of the bushing is formed by the machining method of the semi-circular reference of the thin-walled fan-shaped structural part according to any one of claims 1-9.

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