General process for machining a mounting clamp of an aero-engine and a base in cooperation

Abstract

This invention relates to the field of milling processes, specifically a general process for machining aircraft engine mounting clamps and bases. It includes the following steps: S1, blanking; S2, cubic milling; S3, drilling and reaming process holes and clamping holes; S4, CNC roughing: roughing is performed using an indexable milling cutter, with a cutting allowance reserved and proper datum surface positioning; S5, CNC finishing: during finishing, except for necessary machining allowances reserved on the web surface, spherical surface, and lug hole surface, all other structural features are machined in one pass; S6, blanking by milling; S7, heat treatment; S8, semi-finish grinding; S9, boring; S10, fitting by fitter; S11, finish grinding; S12, turning; S13, measurement and inspection of parts; S14, disassembly of parts; S15, heat treatment; S16, mechanical inspection. This invention can shorten the manufacturing cycle and reduce production costs.

Description

Technical Field

[0001] This invention relates to the field of milling processes, and in particular to a general process for machining mounting clamps and bases for aircraft engines. Background Technology

[0002] 30CrMnSiA(D)-Ⅲ is a very important high-strength structural steel. Its unique forging process gives it higher strength and vibration resistance, and it is commonly used in the production of core components for aircraft.

[0003] Aircraft engine mounting clamps and base parts are key core components of the aircraft engine structure, used for mounting and fixing the engine, and belong to a category of general-purpose machined parts. While the overall design of engine mounting clamps and bases is generally not complex, the manufacturing process is extremely demanding. The quality of the process directly determines the reliability and stability of the aero-engine mounting. On one hand, the two components themselves have extremely high dimensional accuracy and geometric tolerance requirements, making the manufacturing process complex and difficult to guarantee, necessitating high-precision machining such as grinding and turning. On the other hand, to ensure the uniformity of engine mounting hole positions and mounting spherical datum, the mounting clamps and bases also require a combination of processes to complete the final finishing, ensuring that the mounting surfaces and other positioning dimensions are formed in one operation, thereby meeting high-standard mounting requirements and surface precision. Finally, in the actual process, using 30CrMnSiA(D)-Ⅲ steel, it is also necessary to fully consider issues such as stress deformation after heat treatment, actual tool wear, and the selection of appropriate cutting parameters. Therefore, for the machining of aero-engine mounting clamps and bases, it is urgent to propose a reasonable, feasible, stable, and efficient general machining process to shorten the manufacturing cycle and reduce production costs. Summary of the Invention

[0004] The purpose of this invention is to address the problems existing in the background technology by proposing a universal process for the matching processing of aircraft engine mounting clamps and bases, which can shorten the manufacturing cycle and reduce production costs.

[0005] The technical solution of this invention, a general process for machining aircraft engine mounting clamps and bases, includes the following steps:

[0006] S1. Material cutting: Determine the material grade, certificate of conformity, and furnace batch number of the parts, and verify the dimensions of the incoming materials to ensure that the dimensions are within the reasonable range of use.

[0007] S2. Milling the cube: Ensure that the cube dimensions meet the requirements, and at the same time, ensure that the upper and lower planes of the milled cube have the required flatness, which will serve as a rough reference for subsequent machining.

[0008] S3. Drilling, reaming process holes and clamping holes: For 30CrMnSiA steel, the drill bit should be moved forward and backward multiple times during drilling, and coolant should be added in time and the drill bit should be changed frequently.

[0009] S4. CNC roughing: Use indexable milling cutters for roughing. During roughing, allowance should be reserved and reference surfaces should be properly positioned.

[0010] S5. CNC finishing: During finishing, except for the necessary machining allowance on the web surface, spherical surface and ear hole surface, all other structural features are machined in one go. The reserved machining allowance is to prepare for the subsequent process combination and matching work, so as to ensure that the relevant reference dimensions have a margin to be machined when matching and forming, and that the parts are formed in one go.

[0011] S6. Milling blanking: Mill off the connecting block and align it with the machined surface;

[0012] S7. Heat treatment: Heat treatment is performed on 30CrMnSiA steel until the material meets the required mechanical properties. After heat treatment, natural aging is carried out to fully release the internal stress during heat treatment.

[0013] S8. Semi-finish grinding: Semi-finish grinding is performed on the web surface of the part with a reserved allowance, retaining the fine grinding allowance as a reference for subsequent boring of the lug hole;

[0014] S9. Boring: Using the semi-finished flat surface as a reference, bore the ear plate hole to the design size;

[0015] S10. Fitting process matching: Use pins, bolts, and nuts in the same batch number to assemble and match the engine mounting clamps and base, and mark the same number on the parts;

[0016] S11. Fine grinding: Fine grinding is performed on the web surface of the assembly with the reserved allowance.

[0017] S12, Machining: Precision machining of the spherical surface with reserved allowance in the assembly;

[0018] S13. Metrological inspection parts: combined metrological spherical surfaces and other geometric tolerances;

[0019] S14. Disassembling parts: The fitter disassembles the parts and performs local filing and deburring.

[0020] S15. Heat treatment: Residual stress is eliminated after heat treatment of the parts.

[0021] S16. Mechanical Inspector: Inspecting semi-finished products.

[0022] Preferably, in step S2, the flatness is 0.1.

[0023] Preferably, in step S4, during rough machining, a corner radius must be added at the toolpath corner for transition.

[0024] Preferably, in step S5, the machining allowance is 0.5 mm.

[0025] Preferably, in step S7, the material is heat-treated until it meets the mechanical property σb=1175±100MPa, and then naturally aged for more than 36 hours.

[0026] Preferably, in step S8, the part has a pre-reserved allowance of 0.5 mm and a fine grinding allowance of 0.2 mm.

[0027] Preferably, in step S11, a 0.2mm allowance is reserved on the combined web surface.

[0028] Preferably, in step S12, a 0.5mm allowance is reserved for the combined spherical surface.

[0029] Compared with the prior art, the present invention has the following beneficial technical effects:

[0030] This invention can solve technical problems such as mismatched installation of aero engines, difficulty in machining matching parts, easy deformation, and difficulty in ensuring precision dimensions. It greatly improves the machining efficiency of such general-purpose parts, effectively extends the service life of cutting tools, significantly reduces tool costs, saves parts machining costs, and meets the actual production node delivery and equipment requirements. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the clamp structure;

[0033] Figure 3 This is a schematic diagram of the base structure;

[0034] Figure 4 This is a schematic diagram of the assembly structure of the clamp and the base.

[0035] Figure label:

[0036] 100. Clamp; 11. Ear slot a; 12. Ear hole a; 13. Spherical surface a; 14. Recessed groove a; 15. Oil guide hole; 101. Web surface a; 102. Web surface b; 103. Web surface c;

[0037] 200. Base; 21. Ear slot b; 22. Process hole; 23. Spherical surface b; 24. Ear hole b; 25. Recessed groove b; 26. Web groove; 27. Web hole; 201. Web surface d; 202. Web surface e; 203. Web surface f;

[0038] 31. Nut; 32. Bolt; 33. Pin a; 34. Pin b; 35. Composite web surface A; 36. Composite web surface B; 37. Composite sphere. Detailed Implementation

[0039] like Figures 1-4 As shown in this embodiment, a general processing technology for matching aircraft engine mounting clamps and bases includes the following steps:

[0040] S1. Material cutting: Determine the material grade, certificate of conformity, and furnace batch number of the parts, check the dimensions of the incoming materials, and ensure that the dimensions are within the reasonable range of use (dimensional tolerance: +3 to -1mm);

[0041] S2. Milling the cube: While ensuring the cube dimensions, the upper and lower planes of the milled cube must have a certain flatness (flatness 0.1) to serve as a rough reference for subsequent machining.

[0042] S3. Drilling, reaming process holes and clamping holes: For high-strength structural steel such as 30CrMnSiA(D)-Ⅲ, burning of the drill bit and breakage of the drill bit are very likely to occur during actual drilling. Special attention should be paid to the coolant, chip removal and drill bit rigidity. U-drills can be used, and attention should be paid to multiple feeds and retractions, timely replenishment of coolant and frequent replacement of drill bits.

[0043] S4. CNC Roughing: Considering the severe tool wear during steel machining and taking tool cost into account, indexable end mills (such as conventional indexable or high-feed indexable) are used for roughing, with the tool path proceeding from the outside in. Considering subsequent heat treatment, a certain cutting allowance should be reserved during roughing (actual Ap: 1.5mm, depending on the machine tool spindle power and part deformation), and proper datum surface positioning should be ensured. Additionally, a certain radius must be added at toolpath corners during roughing to reduce unnecessary tool impact, extend tool life, and improve economic efficiency. Recommended indexable machining parameters: Spindle speed S: 2000~2500r / min, feed F: 800~1000mm / min, depth of cut Ap conforming to tool cutting parameters, recommended maximum depth of cut 0.7mm.

[0044] S5. CNC Finishing: During finishing, in addition to reserving a 0.5mm machining allowance on the necessary web surfaces (web surface a101, web surface b102, web surface c103, web surface d201, web surface e202 and web surface f203), spherical surfaces (spherical surface a13 and spherical surface b23), and ear hole surfaces (ear hole a12 and ear hole b24), other structural features (such as ear groove a11, recessed groove a14, oil guide hole 15, ear groove b21, process hole) are also finished. 22. The recessed groove (b25), web groove (26), web hole (27), etc. are all machined in one go, and the reserved allowance is to prepare for subsequent process combination and matching work, so as to ensure that the relevant reference dimensions have a margin to be machined and formed in one go when matching. Recommended carbide end mill machining parameters: spindle speed S: 2000~2500r / min, feed F: 400~600mm / min, depth of cut Ap conforms to the tool cutting parameters, and the recommended maximum depth of cut is 0.5mm.

[0045] S6. Milling blanking: Mill off the connecting block and align it with the machined surface;

[0046] S7. Heat treatment: 30CrMnSiA(D)-Ⅲ steel needs to be heat treated until the material meets the mechanical properties σb=1175±100MPa. After heat treatment, it should be naturally aged for more than 36 hours to fully release the internal stress during heat treatment.

[0047] S8. Semi-finish grinding: The web surfaces (web surface a101, web surface b102, web surface c103, web surface d201, web surface e202 and web surface f203) with a 0.5mm allowance are semi-finish ground, leaving a 0.2mm finishing allowance, which serves as a reference for subsequent boring of lug holes (lug hole a12 and lug hole b24);

[0048] S9. Boring: Using the semi-finished flat surface as a reference, bore the ear plate hole to the design size;

[0049] S10, Fitting process matching: Use pins (pin a33 and pin b34), bolts 32, and nuts 31 to assemble and match the engine mounting clamps and base according to the same batch number, and mark the same number on the parts;

[0050] S11. Fine grinding: Fine grinding is performed on the combined web surfaces (combined web surface A35 and combined web surface B36) with a 0.2mm allowance.

[0051] S12, Machining: Perform precision machining on the combined spherical surface 37 with a 0.5mm allowance;

[0052] S13. Metrological inspection parts: combined metrological spherical surfaces and other geometric tolerances;

[0053] S14. Disassembling parts: The fitter disassembles the parts and performs local filing and deburring.

[0054] S15. Heat treatment: Residual stress is eliminated after heat treatment of the parts.

[0055] S16. Mechanical Inspector: Inspecting semi-finished products.

[0056] This embodiment provides a process solution for the general machining of aero-engine mounting clamps and base components. This solution addresses technical challenges such as mismatched aero-engine mounting components, difficult machining of matching parts, susceptibility to deformation, and difficulty in ensuring precise dimensions. It significantly improves machining efficiency for these common components, effectively extends tool life, substantially reduces tooling costs, saves on component machining costs, and meets actual production milestones and equipment requirements. More importantly, this machining process solution for aero-engine mounting clamps and base components is universal and can be referenced, promoted, and applied to the machining of similar components in other aircraft engines.

[0057] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A general processing technology for matching aircraft engine mounting clamps and bases, characterized in that, Includes the following steps: S1. Material cutting: Determine the material grade, certificate of conformity, and furnace batch number of the parts, and verify the dimensions of the incoming materials to ensure that the dimensions are within the reasonable range of use; S2. Milling the cube: Ensure that the cube dimensions meet the requirements, and at the same time, ensure that the upper and lower planes of the milled cube have the required flatness, which will serve as a rough reference for subsequent machining. S3. Drilling, reaming process holes and clamping holes: For 30CrMnSiA steel, the drill bit should be moved forward and backward multiple times during drilling, and coolant should be added in time and the drill bit should be changed frequently. S4. CNC roughing: Use indexable milling cutters for roughing. During roughing, allowance should be reserved and reference surfaces should be properly positioned. S5. CNC finishing: During finishing, except for the necessary machining allowance on the web surface, spherical surface and ear hole surface, all other structural features are machined in one go. The reserved machining allowance is to prepare for the subsequent process combination and matching work, so as to ensure that the relevant reference dimensions have a margin to be machined when matching and forming, and that the parts are formed in one go. S6. Milling blanking: Mill off the connecting block and align it with the machined surface; S7. Heat treatment: Heat treatment is performed on 30CrMnSiA steel until the material meets the required mechanical properties. After heat treatment, natural aging is carried out to fully release the internal stress during heat treatment. S8. Semi-finish grinding: Semi-finish grinding is performed on the web surface of the part with a reserved allowance, retaining the fine grinding allowance as a reference for subsequent boring of the lug hole; S9. Boring: Using the semi-finished flat surface as a reference, bore the ear plate hole to the design size; S10. Fitting process matching: Use pins, bolts, and nuts in the same batch number to assemble and match the engine mounting clamps and base, and mark the same number on the parts; S11. Fine grinding: Fine grinding is performed on the web surface of the assembly with the reserved allowance. S12, Machining: Precision machining of the spherical surface with reserved allowance in the assembly; S13. Metrological inspection parts: combined metrological spherical surfaces and other geometric tolerances; S14. Disassembling parts: The fitter disassembles the parts and performs local filing and deburring. S15. Heat treatment: Residual stress is eliminated after heat treatment of the parts. S16. Mechanical Inspector: Inspecting semi-finished products.

2. The general processing technology for matching aircraft engine mounting clamps and bases according to claim 1, characterized in that, In step S2, the flatness is 0.

1.

3. The general processing technology for matching aircraft engine mounting clamps and bases according to claim 2, characterized in that, In step S4, during rough machining, corner radius arcs must be added at toolpath corners for transition.

4. The general processing technology for matching aircraft engine mounting clamps and bases according to claim 3, characterized in that, In step S5, a machining allowance of 0.5mm is reserved.

5. The general processing technology for matching aircraft engine mounting clamps and bases according to claim 4, characterized in that, In step S7, the material is heat-treated until it meets the mechanical property requirement of σb = 1175 ± 100 MPa, and then naturally aged for more than 36 hours.

6. The general processing technology for matching aircraft engine mounting clamps and bases according to claim 5, characterized in that, In step S8, the part has a pre-reserved allowance of 0.5mm and a fine grinding allowance of 0.2mm.

7. The general processing technology for matching aircraft engine mounting clamps and bases according to claim 6, characterized in that, In step S11, a 0.2mm allowance is reserved on the combined web surface.

8. The general processing technology for matching aircraft engine mounting clamps and bases according to claim 7, characterized in that, In step S12, a 0.5mm allowance is reserved for the combined spherical surface.

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