Non-rigid casing and its constrained machining method

Abstract

The application discloses a non-rigid casing and a constraint machining method thereof, and belongs to the technical field of machining, comprising a technological process and constraint conditions. The application is used to solve the problem that the machining method of the non-rigid casing in the prior art is prone to deformation in the machining process, causes the coaxiality or position degree of the part to be out of tolerance, affects the assembly precision, and increases the assembly stress. The application clearly distinguishes the technical requirements of the constraint state and the free state, and strengthens the control of the deformation amount. The flatness error of the control reference surface in the free state reduces the compression deformation of the casing; the roundness error of the control reference circle in the free state reduces the positioning deformation of the casing; the technical requirements of the free state strengthen the control of the cutting parameters, i.e. the cutting force; the reasonable constraint conditions limit the shape error of the casing machining state, so that the casing machining state is consistent with the assembly state, the assembly precision of the casing on the engine is improved, and the assembly stress is reduced.

Description

Technical Field

[0001] This invention belongs to the field of machining technology, specifically relating to a constraint machining method for a non-rigid casing. Background Technology

[0002] Aero engines have extremely strict weight control requirements. They utilize material stiffness and structural stiffness to ensure the overall rigidity of the engine. That is, while meeting the overall rigidity requirements of the engine, the weight of the components is controlled as much as possible. Therefore, aero engines use a large number of thin-walled parts, which are relatively weak and are collectively referred to as non-rigid components. During the manufacturing process, as the blank allowance is continuously removed and the structural dimensions of the parts are gradually refined, the internal stress of the parts changes continuously. The changes in internal stress cause deformation of the parts, affecting the manufacturing accuracy.

[0003] During manufacturing, deformation of non-rigid components poses significant challenges to the inspection and acceptance of parts. Currently, the industry commonly employs a method of performing limit checks during the manufacturing process and reviewing process records upon delivery. While this approach avoids the impact of machining deformation on inspection results, it masks flaws in process design and loopholes in quality control during manufacturing, often resulting in defective products being delivered as "qualified."

[0004] Some have suggested performing limit checks on non-rigid parts during finished product delivery and acceptance. However, verification revealed that while limit checks do improve the pass rate of the measured elements, the pass rate is not high and is unstable. Further research showed that the results of limit checks are not only related to the limit method and limit size, but also to the process control methods and the magnitude of part deformation during manufacturing. Only by implementing reasonable process methods and strictly controlling the amount of deformation can the limit check results be stable and meet design requirements.

[0005] The compressor casing of a certain new type of aero-engine is a typical non-rigid component, such as... Figure 1 As shown, its structure is a split type consisting of upper and lower halves. To ensure coaxiality with the front and rear casings and radial clearance between rotating and stationary components, strict requirements for circular runout, coaxiality, or positional accuracy are specified between the front and rear positioning elements of the casing, such as... Figures 2-4 As shown. Due to machining deformation, improper process design can cause the coaxiality or positional accuracy of parts to exceed tolerances, affecting assembly accuracy and increasing assembly stress.

[0006] In summary, the existing processing methods for non-rigid housings are prone to deformation during processing, causing deviations in the coaxiality or position of parts, affecting assembly accuracy, and increasing assembly stress. Summary of the Invention

[0007] The purpose of this invention is to provide a non-rigid housing and its constrained machining method, including the process flow and constraint conditions. This addresses the problem that existing machining methods for non-rigid housings are prone to deformation during processing, causing deviations in the coaxiality or position of parts, affecting assembly accuracy, and increasing assembly stress. This method reduces machining deformation and ensures that the finished state of the housing matches the assembly state, effectively improving the manufacturing accuracy of the housing, guaranteeing assembly accuracy, and reducing assembly stress.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A constraint machining method for a non-rigid housing includes: during finishing, axially clamping the part, and then precision machining the front reference surface to provide a reference surface for the next process;

[0010] Using the front datum surface as a reference, the part is axially clamped; the rear datum surface and the rear datum hole are precision machined.

[0011] Using the rear datum surface and rear datum hole as references, a fixture is used to constrain and support the rear datum surface of the part, locate the rear datum hole, and clamp the back side of the mounting edge; the front section of the housing is precision machined, and the machining is performed without clamping deformation or positioning deformation. The amount of deformation after machining is controlled by adjusting the cutting parameters.

[0012] Using the front reference surface as a reference, a fixture is used to constrain and support the front face of the part, locate the front reference hole, and press the back of the front mounting edge; the rear section of the housing is precision machined, and the machining is performed under the condition of controlling the pressing deformation and positioning deformation. The amount of deformation after machining is controlled by adjusting the cutting parameters.

[0013] Using the rear datum surface and rear datum hole as references, a fixture is used to constrain and support the rear datum surface of the part, position the rear datum hole, and clamp it to the back side of the mounting edge; at the same time, the front datum hole is rounded and constrained; holes on the mounting edge are drilled and bored before drilling and boring; holes are drilled and bored with the front and rear datum holes rounded to ensure the positional accuracy of the holes and control the distance difference between each precision hole drilled and bored and the wall of the datum hole;

[0014] The part is constrained by a fixture, the front end face of the part is supported, the front reference hole is positioned, the precision hole on the front mounting edge is positioned, and the back side of the front mounting edge is pressed; at the same time, the rear reference hole is rounded and constrained; the hole on the rear mounting edge is drilled and bored; the holes are drilled and bored while the reference holes at both ends are rounded to ensure the positional accuracy of the holes and control the distance difference between each precision hole drilled and bored and the wall of the reference hole.

[0015] Preferably, before finishing the part, the blank is rough-machined and semi-finished to remove large excess material; and heat treatment is performed to eliminate residual stress in the blank and residual stress from rough machining.

[0016] Preferably, when precision machining the front reference surface, align the front inner hole, and the runout at the point should not exceed 0.2mm; use a four-jaw chuck to gently press against the outer circle of the rear mounting edge to prevent the part from moving during machining; use a pressure plate to press down the back of the rear mounting edge, and the gap under the reference surface corresponding to the position of the front pressure plate should not exceed 0.02mm, otherwise add a feeler gauge for adjustment.

[0017] Preferably, when precision machining the rear end reference surface and the rear end reference hole, align the rear end inner hole, and the runout at the point should not exceed 0.02mm; use a four-jaw chuck to gently press against the outer circle of the front mounting edge to prevent the part from moving during machining; use a pressure plate to press down on the back of the front mounting edge, and the gap under the reference surface corresponding to the position of the front pressure plate should not exceed 0.02mm, otherwise add a feeler gauge for adjustment.

[0018] Preferably, when machining the front section of the housing, the total runout of the positioning end face of the alignment fixture is no more than 0.01mm, and the circumferential runout of the positioning outer circle of the alignment fixture is no more than 0.005mm; before clamping, use a feeler gauge to check the gap between the rear end face and the positioning end face of the fixture to confirm that the housing is clamped in place; after clamping, use a feeler gauge to check the gap of the reference surface, and the local gap is no more than 0.02mm.

[0019] Preferably, when machining the rear section of the housing, the total runout of the positioning end face of the alignment fixture is no more than 0.01mm, and the circumferential runout of the positioning outer circle of the alignment fixture is no more than 0.005mm; before clamping, use a feeler gauge to check the gap between the front end face and the positioning end face of the fixture to confirm that the housing is clamped in place; after clamping, use a feeler gauge to check the gap of the reference surface, and the local gap is no more than 0.02mm.

[0020] Preferably, when drilling and boring the holes on the mounting edge, the total runout of the positioning end face of the aligning fixture should not exceed 0.01mm, and the runout of the outer circle of the positioning fixture should not exceed 0.005mm; before clamping, use a feeler gauge to check the gap between the rear end face of the housing and the positioning end face of the fixture to confirm that the housing is clamped in place; after clamping, use a feeler gauge to check the gap of the reference surface, and the local gap should not exceed 0.02mm.

[0021] Preferably, when installing the side hole after drilling and boring, the total runout of the positioning end face of the alignment fixture is no more than 0.01mm, and the runout of the outer circle of the positioning fixture is no more than 0.005mm; before clamping, use a feeler gauge to check the gap between the front end face of the housing and the positioning end face of the fixture to confirm that the housing is clamped in place; after clamping, use a feeler gauge to check the gap of the reference surface, and the local gap is no more than 0.02mm.

[0022] Preferably, when drilling and boring the holes on the mounting edge, the front reference hole is rounded and constrained while positioning the rear reference hole; the holes are drilled and bored while the reference holes at both ends are rounded to ensure the positional accuracy of the holes and control the distance difference between each precision hole drilled and bored and the wall of the reference hole.

[0023] When drilling and boring the holes on the mounting side, while positioning the front reference hole, the rear reference hole is rounded and constrained; the holes are drilled and bored while the reference holes at both ends are rounded to ensure the positional accuracy of the holes and control the distance difference between each precision hole drilled and bored and the wall of the reference hole.

[0024] A non-rigid housing is manufactured using the constraint machining method for a non-rigid housing described in any one of the above-mentioned methods.

[0025] Compared with the prior art, the present invention has the following beneficial technical effects:

[0026] This invention provides a constrained machining method for non-rigid casings, clearly distinguishing the technical requirements of constrained and free states, and strengthening the control of deformation. Controlling the flatness error of the reference surface in the free state reduces the clamping deformation of the casing; controlling the roundness error of the reference circle in the free state reduces the positioning deformation of the casing; controlling the technical requirements of the free state strengthens the control of cutting parameters, i.e., cutting forces; and employing reasonable constraint conditions limits the shape error of the casing's machining state, ensuring consistency between the machined and assembled states, improving the assembly accuracy of the casing on the engine, and reducing assembly stress. This invention can be extended to the machining of other non-rigid parts, as well as to other manufacturing fields such as aerospace and gas turbines, improving the manufacturing accuracy of parts and better meeting assembly requirements.

[0027] Furthermore, the present invention controls the flatness of the front reference end face and the rear reference end face in the free state, reduces compression deformation, and improves manufacturing accuracy.

[0028] Furthermore, the present invention controls the roundness of the front and rear reference holes in the free state, reduces positioning deformation, and improves manufacturing accuracy.

[0029] Furthermore, the present invention drills and bores holes on the mounting edge under the constraint of the reference hole's circularity, thereby limiting the roundness error of the reference hole, thus controlling the distance error between the precision hole on the mounting edge and its adjacent reference hole wall surface, improving assembly accuracy and reducing assembly stress.

[0030] Furthermore, the present invention simulates the assembly state of the casing on the engine, with the front reference hole and the precision hole on the front mounting edge being positioned simultaneously, while the rear reference hole is constrained to a round shape. Under this state, the precision hole on the rear mounting edge is drilled and bored, which effectively ensures the overall positional accuracy of the precision hole on the rear mounting edge relative to the precision hole on the front mounting edge, thereby improving the assembly accuracy of the engine. Attached Figure Description

[0031] Figure 1 For a certain type of aero-engine, it is a split compressor casing;

[0032] Figure 2This is a front view of the compressor casing;

[0033] Figure 3 for Figure 2 The A-direction view of the main view;

[0034] Figure 4 for Figure 2 View B of the main view;

[0035] Figure 5 This is a sketch of process 1;

[0036] Figure 6 This is a sketch of process 2;

[0037] Figure 7 This is a sketch of process 3;

[0038] Figure 8 This is a sketch of process 4;

[0039] Figure 9 This is a sketch of process 5;

[0040] Figure 10 This is a sketch of process 6. Detailed Implementation

[0041] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0042] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0045] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0046] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0047] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0048] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0049] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0050] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0051] Example 1

[0052] This invention discloses a constrained machining method for a compressor casing, comprising a process flow and constraint conditions. This method reduces machining deformation and ensures that the finished machining state of the casing matches its assembly state, effectively improving the manufacturing accuracy of the casing, guaranteeing the assembly accuracy of the casing, and reducing assembly stress. The specific details are as follows:

[0053] 1) Process Flow

[0054] 0: Rough machining + stress relief + semi-finishing (completed before finishing) → 1: Finish turning the front datum surface → 2: Finish turning the rear datum surface and datum hole → 3: Finish turning the front section of the housing → 4: Finish turning the rear section of the housing → 5: Drilling and boring the mounting side holes before mounting → 6: Drilling and boring the mounting side holes after mounting.

[0055] 2) Constraints and main technical requirements

[0056] Process 0:

[0057] (1) Purpose of the process: to remove large excess material; heat treatment to eliminate residual stress in the blank and residual stress in the roughing process; semi-finishing.

[0058] Process 1:

[0059] (1) Purpose of the process: to provide a reference plane close to the theoretical plane for the next process and to control the compression deformation.

[0060] (2) Constraints: Axial compression, to keep the parts free as much as possible.

[0061] (3) Main technical requirements: Flatness of the front end face in a free state, such as... Figure 5 As shown.

[0062] Process 2:

[0063] (1) Purpose of the process: to provide a reference surface close to the theoretical plane for the next process and control the compression deformation; to provide a positioning circle close to the theoretical shape for the next process and control the elastic deformation caused by positioning.

[0064] (2) Constraints: Axial compression, to keep the parts free as much as possible.

[0065] (3) Main technical requirements: Flatness of the rear end face in the free state; Roundness of the rear end reference hole in the free state, such as... Figure 6 As shown.

[0066] Process 3:

[0067] (1) Purpose of the process: to perform finishing without clamping deformation and positioning deformation, and to control the amount of deformation after machining; at the same time, to control the machining deformation of this process by reducing the cutting force through cutting parameters.

[0068] (2) Constraints: The part is constrained by a fixture, supported by the rear end face, positioned by the rear datum hole (constrained by the maximum material size of the positioning hole), and then mounted on the back side after clamping.

[0069] (3) Main technical requirements: flatness of the front end face in the free state; roundness of the front end reference hole in the free state, such as... Figure 7 As shown.

[0070] Step 4:

[0071] (1) Purpose of the process: to perform finishing under controlled pressure deformation and positioning deformation, thereby reducing the amount of deformation after machining; at the same time, to reduce the cutting force by cutting parameters and control the machining deformation of this process.

[0072] (2) Constraints: The part is constrained by a fixture, supported by the front end face, positioned by the front reference hole (constrained by the maximum material size of the positioning hole), and the back of the front mounting edge is pressed.

[0073] (3) Main technical requirements: Parallelism of the rear end face to the front end face under constrained conditions; Circular runout of the rear end reference hole relative to the front end reference hole under constrained conditions; Flatness of the rear end face under free conditions; Roundness of the rear end reference hole under free conditions, such as... Figure 8 As shown.

[0074] Step 5:

[0075] (1) Purpose of the process: Drilling and boring holes in the rounded state of the front and rear reference holes to ensure the positional accuracy of the holes. Its deeper purpose is to control the distance difference between each precision hole drilled and bored and the wall of the reference hole.

[0076] (2) Constraint conditions: The fixture is used for constraint, the rear end face is supported, the rear end reference hole is positioned (constrained by the maximum material size of the positioning hole), and the back side of the mounting edge is pressed; at the same time, the front end reference hole is constrained by rounding (constrained by the maximum material size of the rounded hole).

[0077] (3) Main technical requirements: Position accuracy of the precision hole on the front mounting edge under constrained conditions, such as... Figure 9 As shown.

[0078] Step 6:

[0079] (1) Purpose of the process: Drilling and boring holes while the reference holes at both ends are simultaneously rounded to ensure the position of the holes. Its deeper purpose is to control the distance difference between each precision hole drilled and bored and the wall of the reference hole.

[0080] (2) Constraints: The fixture is used for constraint, the front end face is supported, the front end reference hole is positioned (constrained by the maximum material size of the positioning hole), and the 18 precision holes on the front mounting edge are positioned (constrained by the maximum material size of the precision hole minus the hole position value), pressing the back of the front mounting edge; at the same time, the rear end reference hole is rounded and constrained (constrained by the maximum material size of the rounded hole).

[0081] (3) Main technical requirements: Positional accuracy of the precision holes on the rear mounting edge relative to their adjacent reference holes under constrained conditions; overall positional accuracy of the precision holes on the rear mounting edge relative to the precision holes on the front mounting edge under constrained conditions, such as... Figure 10 As shown.

[0082] This invention applies the GB / T 16892-1997 "Form and Position Tolerances for Non-rigid Parts" standard to the annotation of process drawings, clearly distinguishing the inspection requirements for constrained and free states, breaking the habit of inspecting process technical requirements entirely at the upper limit of the fixture, and strengthening the control requirements for process deformation.

[0083] This invention controls the flatness of the front and rear reference end faces in a free state, reduces compression deformation, and improves manufacturing precision.

[0084] This invention controls the roundness of the front and rear reference holes in a free state, reduces positioning deformation, and improves manufacturing accuracy.

[0085] This invention drills and bores holes on the mounting edge under the constraint of a rounded reference hole, which limits the roundness error of the reference hole, thereby controlling the distance error between the precision hole on the mounting edge and its adjacent reference hole wall, improving assembly accuracy and reducing assembly stress.

[0086] This invention simulates the assembly state of the casing on the engine, using the front reference hole and the precision hole on the front mounting edge for simultaneous positioning, while simultaneously constraining the rear reference hole to a round shape. Under this state, the precision hole on the rear mounting edge is drilled and bored, which effectively ensures the overall positional accuracy of the precision hole on the rear mounting edge relative to the precision hole on the front mounting edge, thereby improving the assembly accuracy of the engine.

[0087] Example 2

[0088] Process 0:

[0089] The roughing, stress relief, and semi-finishing processes preceding the finishing are not related to the technical points of this invention and will not be elaborated here.

[0090] Process 1: Precision machining of the front reference surface

[0091] 1) Equipment requirements: CNC vertical lathe or ordinary vertical lathe.

[0092] 2) Fixture alignment requirements: No fixtures are used.

[0093] 3) Part alignment requirements: Align the front inner hole, with a runout of no more than 0.2mm; use a four-jaw chuck to gently press against the outer circle of the rear mounting edge to prevent the part from moving during machining.

[0094] 4) Part clamping requirements: After clamping with 6 clamping plates, the back of the mounting edge should be clamped. The gap under the reference surface corresponding to the position of the clamping plate before clamping should not be greater than 0.02mm. If necessary, add copper shims or feeler gauges.

[0095] 5) Machining and inspection points: Control the cutting force to ensure the flatness of the front end face in the free state.

[0096] Step 2: Finish machining of the rear datum surface and datum hole

[0097] 1) Equipment requirements: CNC vertical lathe or ordinary vertical lathe.

[0098] 2) Fixture alignment requirements: No fixtures are used.

[0099] 3) Part alignment requirements: Align the inner hole at the rear end, with a runout of no more than 0.02mm; use a four-jaw chuck to gently press against the outer circle of the rear mounting edge to prevent the part from moving during machining.

[0100] 4) Part clamping requirements: After clamping with 6 clamping plates, the back of the mounting edge should be clamped. The gap between the clamping plates and the reference surface should not be greater than 0.02mm. If necessary, add a feeler gauge.

[0101] 5) Machining and inspection points: Control the cutting force, ensure the flatness of the rear end face in the free state, and ensure the roundness of the rear end reference hole in the free state.

[0102] Process 3: Precision machining of the front section of the housing

[0103] 1) Equipment requirements: CNC vertical lathe or CNC horizontal lathe.

[0104] 2) Fixture alignment requirements: The total runout of the positioning end face of the alignment fixture shall not exceed 0.01mm, and the circumferential runout of the positioning outer circle of the alignment fixture shall not exceed 0.005mm.

[0105] 3) Part alignment requirements: No part alignment is required.

[0106] 4) Part clamping requirements: Before clamping, use a feeler gauge to check the gap between the front end face and the positioning end face of the fixture to confirm that the housing is clamped in place; after clamping, use a feeler gauge to check the gap of the reference surface, and the local gap should not be greater than 0.02mm.

[0107] 5) Machining and Inspection Points: Strictly control cutting parameters to control cutting force and machining deformation. With the fixture in a constrained state, inspect the diameter of the front reference hole, the total runout of the front reference surface, and the circular runout of the front reference hole. Remove the housing and, in a free state, inspect the flatness of the front face and the roundness of the front reference hole.

[0108] Process 4: Finish machining of the rear section of the housing

[0109] 1) Equipment requirements: CNC vertical lathe or CNC horizontal lathe.

[0110] 2) Fixture alignment requirements: The total runout of the positioning end face of the alignment fixture shall not exceed 0.01mm, and the circumferential runout of the positioning outer circle of the alignment fixture shall not exceed 0.005mm.

[0111] 3) Part alignment requirements: No part alignment is required.

[0112] 4) Part clamping requirements: Before clamping, use a feeler gauge to check the gap between the rear end face and the positioning end face of the fixture to confirm that the housing is clamped in place; after clamping, use a feeler gauge to check the gap of the reference surface, and the local gap should not be greater than 0.02mm.

[0113] 5) Machining and Inspection Points: Strictly control cutting parameters to control cutting force and machining deformation. With the fixture in a constrained state, inspect the diameter of the rear datum hole and the parallelism of the rear datum surface; inspect the circular runout of the rear datum hole. Remove the casing and, in a free state, inspect the flatness of the front face and the roundness of the front datum hole.

[0114] Step 5: Drilling and boring the holes on the mounting edge before installation.

[0115] 1) Equipment requirements: Vertical CNC coordinate boring machine.

[0116] 2) Fixture alignment requirements: The total runout of the positioning end face of the alignment fixture shall not exceed 0.01mm, and the circumferential runout of the positioning outer circle of the alignment fixture shall not exceed 0.005mm.

[0117] 3) Part alignment requirements: No part alignment is required.

[0118] 4) Part clamping requirements: Before clamping, use a feeler gauge to check the gap between the rear end face and the positioning end face of the fixture to confirm that the housing is clamped in place; after clamping, use a feeler gauge to check the gap of the reference surface, and the local gap should not be greater than 0.02mm.

[0119] 5) Front support ring clamping and alignment requirements: Install the front support ring and use a feeler gauge to check the gap between the lower reference surface of the front support ring and the front end face of the casing. A 0.02mm feeler gauge should not pass through. Align the inner bore of the front support ring so that the circular runout is no more than 0.005mm.

[0120] 6) Processing and inspection points: Use a special position measurement tool to inspect the position of the precision holes on the mounting edge before installation.

[0121] Step 6: Drill and bore the holes on the mounting edge.

[0122] 1) Equipment requirements: Vertical CNC coordinate boring machine.

[0123] 2) Fixture alignment requirements: The total runout of the positioning end face of the alignment fixture shall not exceed 0.01mm, and the circumferential runout of the positioning outer circle of the alignment fixture shall not exceed 0.005mm.

[0124] 3) Part alignment requirements: No part alignment is required.

[0125] 4) Part clamping requirements: Before clamping, use a feeler gauge to check the gap between the front face of the housing and the positioning end face of the fixture to confirm that the housing is clamped in place; after clamping, use a feeler gauge to check the gap of the reference surface, and the local gap should not be greater than 0.02mm.

[0126] 5) Rear support ring clamping and inspection requirements: Install the rear support ring and use a feeler gauge to check the gap between the lower reference surface of the rear support ring and the rear end face of the casing. The feeler gauge should not pass through with a diameter of 0.02 mm. Check that the circular runout of the inner hole of the rear support ring is not greater than 0.03 mm. Note that this is only for inspection and the inner hole of the rear support ring should not be aligned.

[0127] 6) Processing and inspection points: Use a special position measurement tool to inspect the position of the precision holes on the mounting edge after installation, including the overall position of the precision holes on the front mounting edge.

[0128] Processing completed.

[0129] This invention applies the GB / T 16892-1997 "Standard for Geometric Tolerances of Non-rigid Parts" to the annotation of process drawings, clearly distinguishing the technical requirements of constrained and free states, and strengthening the control of deformation. Controlling the flatness error of the datum surface in the free state reduces the clamping deformation of the casing; controlling the roundness error of the datum circle in the free state reduces the positioning deformation of the casing; controlling the technical requirements of the free state strengthens the control of cutting parameters, i.e., cutting forces; and using reasonable constraint conditions limits the shape error of the casing's machining state, ensuring that the machining state of the casing is consistent with the assembly state, improving the assembly accuracy of the casing on the engine, and reducing assembly stress.

[0130] This invention can be extended to the processing of other non-rigid parts, as well as to other manufacturing fields such as aerospace and gas turbines, and can improve the manufacturing precision of parts and better meet assembly requirements.

[0131] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0132] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for constraining the machining of a non-rigid housing, characterized in that, include: During finishing, the part is axially clamped, and then the front reference surface is precision machined to provide a reference surface for the next process; Using the front datum surface as a reference, the part is axially clamped; the rear datum surface and the rear datum hole are precision machined. Using the rear datum surface and rear datum hole as references, a fixture is used to constrain and support the rear datum surface of the part, locate the rear datum hole, and clamp the back side of the mounting edge; the front section of the housing is precision machined, and the machining is performed without clamping deformation or positioning deformation. The amount of deformation after machining is controlled by adjusting the cutting parameters. Using the front reference surface as a reference, a fixture is used to constrain and support the front face of the part, locate the front reference hole, and press the back of the front mounting edge; the rear section of the housing is precision machined, and the machining is performed under the condition of controlling the pressing deformation and positioning deformation. The amount of deformation after machining is controlled by adjusting the cutting parameters. Using the rear datum surface and rear datum hole as references, a fixture is used to constrain and support the rear datum surface of the part, position the rear datum hole, and clamp it to the back side of the mounting edge; at the same time, the front datum hole is rounded and constrained; holes on the mounting edge are drilled and bored before drilling and boring; holes are drilled and bored with the front and rear datum holes rounded to ensure the positional accuracy of the holes and control the distance difference between each precision hole drilled and bored and the wall of the datum hole; The part is constrained by a fixture, the front end face of the part is supported, the front reference hole is positioned, the precision hole on the front mounting edge is positioned, and the back side of the front mounting edge is pressed; at the same time, the rear reference hole is rounded and constrained; the hole on the rear mounting edge is drilled and bored; the holes are drilled and bored while the reference holes at both ends are rounded to ensure the positional accuracy of the holes and control the distance difference between each precision hole drilled and bored and the wall of the reference hole.

2. The constraint machining method for a non-rigid casing according to claim 1, characterized in that, Before finishing the parts, the blanks are rough-machined and semi-finished to remove large excess material; and heat treatment is performed to eliminate residual stress in the blanks and residual stress from rough machining.

3. The constraint machining method for a non-rigid casing according to claim 1, characterized in that, When precision machining the front reference surface, align the front inner hole, ensuring the runout at the point is no more than 0.2mm; use a four-jaw chuck to gently press against the outer circle of the rear mounting edge to prevent the part from moving during machining; use a pressure plate to press down the back of the rear mounting edge, ensuring the gap under the reference surface corresponding to the position of the front pressure plate is no more than 0.02mm, otherwise add a feeler gauge for adjustment.

4. The constraint machining method for a non-rigid casing according to claim 1, characterized in that, When precision machining the rear datum surface and rear datum hole, align the rear inner hole, ensuring the runout at the point is no greater than 0.02mm; use a four-jaw chuck to gently press against the outer circle of the front mounting edge to prevent the part from moving during machining; use a pressure plate to press down on the back of the front mounting edge, ensuring the gap under the datum surface corresponding to the position of the pressure plate is no greater than 0.02mm, otherwise adjust with a feeler gauge.

5. The constraint machining method for a non-rigid casing according to claim 1, characterized in that, When machining the front section of the housing, the total runout of the positioning end face of the alignment fixture should not exceed 0.01mm, and the runout of the outer circle of the positioning fixture should not exceed 0.005mm. Before clamping, use a feeler gauge to check the gap between the rear end face and the positioning end face of the fixture to confirm that the housing is clamped in place. After clamping, use a feeler gauge to check the gap of the reference surface, and the local gap should not exceed 0.02mm.

6. The constraint machining method for a non-rigid casing according to claim 1, characterized in that, When machining the rear section of the housing, the total runout of the positioning end face of the alignment fixture should not exceed 0.01mm, and the runout of the outer circle of the positioning fixture should not exceed 0.005mm. Before clamping, use a feeler gauge to check the gap between the front end face and the positioning end face of the fixture to confirm that the housing is clamped in place. After clamping, use a feeler gauge to check the gap of the reference surface, and the local gap should not exceed 0.02mm.

7. The constraint machining method for a non-rigid casing according to claim 1, characterized in that, When drilling and boring the holes on the mounting edge, the total runout of the locating end face of the aligning fixture should not exceed 0.01mm, and the runout of the outer circle of the locating fixture should not exceed 0.005mm. Before clamping, use a feeler gauge to check the gap between the rear end face of the housing and the locating end face of the fixture to confirm that the housing is clamped in place. After clamping, use a feeler gauge to check the gap of the reference surface, and the local gap should not exceed 0.02mm. When installing the side holes after drilling and boring, the total runout of the positioning end face of the aligning fixture should not exceed 0.01mm, and the runout of the outer circle of the positioning fixture should not exceed 0.005mm. Before clamping, use a feeler gauge to check the gap between the front face of the housing and the positioning end face of the fixture to confirm that the housing is clamped in place. After clamping, use a feeler gauge to check the gap of the reference surface, and the local gap should not exceed 0.02mm.

8. The constraint machining method for a non-rigid casing according to claim 1, characterized in that, When drilling and boring the holes on the mounting edge, while positioning the rear reference hole, the front reference hole is rounded and constrained; while drilling and boring the holes with both reference holes rounded at the same time, the positional accuracy of the holes is guaranteed, and the distance difference between each precision hole drilled and bored and the reference hole wall is controlled.

9. The constraint machining method for a non-rigid casing according to claim 1, characterized in that, When drilling and boring the holes on the mounting side, while positioning the front reference hole, the rear reference hole is rounded and constrained; the holes are drilled and bored while the reference holes at both ends are rounded to ensure the positional accuracy of the holes and control the distance difference between each precision hole drilled and bored and the wall of the reference hole.

10. A non-rigid housing, characterized in that, It is manufactured using the constraint machining method described in any one of claims 1 to 9 for a non-rigid casing.

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