A machining method of a high-precision complex aero-engine fuel nozzle rod

Abstract

The application discloses a kind of high-precision complex aero-engine fuel nozzle rod processing methods, comprising the following steps: S1, with the reference C of part middle rod part as transverse reference, reference A and end surface reference B as axial reference;S2, clamping part;S3, design the processing sequence of part feature;S4, prepare different feature numerical control processing procedure, the same feature of different parts is programmed and processed once;S5, the program prepared is simulated, and processing parameter is optimized;S6, start machine tool and process part;The nozzle rod processing method proposed in the application reduces clamping error and alignment error in processing process, improves part processing precision and processing efficiency.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine fuel nozzle rod processing, and in particular, relates to a method for processing high-precision complex aero-engine fuel nozzle rods. Background Technology

[0002] Fuel nozzles are a crucial component of the high-precision, complex engine combustion chamber. Their function is to deliver high-pressure fuel from the fuel header to the combustion chamber for combustion. A single aero-engine requires 14 to 18 nozzles, and they directly influence the temperature field of the combustion chamber, thus affecting the overall engine performance and lifespan. Key components of high-precision engine fuel nozzles include the nozzle rod, nozzle orifice, and swirler. The nozzle rod, made of cast high-temperature alloy, is particularly challenging to machine. Figure 1 As shown, its structure is complex, irregular, and asymmetrical, and it has high machining precision, with dimensional tolerances of 0.008 to 0.03 mm and form and position tolerances of 0.008 to 0.02 mm.

[0003] The existing processing method is relatively complex, requiring five CNC vertical machining processes to complete all feature machining, and four machining datum conversions are required. The datum conversion error is large, which can easily lead to problems such as long machining cycle of nozzle rod, low machining efficiency and low precision dimension qualification rate.

[0004] Existing patent publication number CN104097008A discloses a method for processing a fuel nozzle, including the following steps: Step S20: connecting the nozzle seat and the second pin, the nozzle seat and the first pin, the nozzle seat and the sleeve, the nozzle seat and the fuel pipe, the housing and the fuel pipe, and the housing and the nozzle outlet by spot welding; Step S30: the weld seam between the nozzle seat and the second pin, the weld seam between the nozzle seat and the first pin, and the weld seam between the nozzle seat and the sleeve. The process involves adding solder to the weld seam between the nozzle seat and the fuel pipe, the weld seam between the housing and the fuel pipe, and the weld seam between the housing and the nozzle; step S40: fixing the fuel nozzle with the added solder using a fixing fixture; step S50: heating the fuel nozzle in a vacuum furnace to melt the solder and weld the nozzle seat, the sleeve, the fuel pipe, the housing, the nozzle, the first pin, and the second pin together; step S60: cooling the heated fuel nozzle. The drawback of this patent is its complex process, requiring multiple clamping and reference conversions, resulting in a large reference conversion error and low processing accuracy and efficiency. Summary of the Invention

[0005] This invention discloses a high-precision machining method for complex aero-engine fuel nozzle rods. By combining the structural characteristics of the part and designing a reasonable part fixture, a CNC five-axis machining center is used to optimize and merge the original five scattered and long machining processes into one machining process, thereby reducing clamping and alignment errors during the machining process and improving the machining accuracy and efficiency of the parts.

[0006] To address the aforementioned technical problems, the technical solution of the present invention is as follows:

[0007] A method for machining a high-precision, complex aero-engine fuel nozzle rod includes the following steps:

[0008] S1. Blank datum conversion: The datum A on the blank is converted to the three holes on the end face through CNC process. The datum C of the middle rod is used as the transverse datum, and the datum A and the end face datum B are used as the axial datum.

[0009] S2. Clamping parts: Design a fixture based on the positions of the reference A, the intermediate rod reference C and the end face reference B, position and fix the end face reference B and reference A, and press down the intermediate rod reference C;

[0010] S3. Design the machining path of the part features: The main machining features of the part include the first oil inlet hole, the second oil inlet hole, the mounting hole and the internal nozzle structure. According to the characteristics of the part clamping, the first oil inlet hole, the second oil inlet hole, the mounting hole and the internal nozzle structure on the two parts are machined in sequence, and the same features on the two parts are machined at once.

[0011] S4. Compile CNC machining programs: Based on the fixture dimensions, establish machining coordinates for the different features of the two parts; according to the machining sequence of the part features, compile CNC machining programs for different features, with the same features of the two parts programmed and machined one at a time; the specific programming can use existing programming methods and programs.

[0012] S5. Simulate the compiled program to check for problems in the machining program and optimize the machining parameters;

[0013] S6. Start the machine tool to process the parts.

[0014] Furthermore, in step S1, the reference A, the intermediate rod reference C, and the end face reference B are all machined references.

[0015] Furthermore, in step S2, the fixture includes a fixture base plate and a mounting base, with two mounting bases symmetrically arranged above the fixture base plate.

[0016] Furthermore, the height of the mounting base is the minimum height required for the machine tool spindle to process the parts.

[0017] Furthermore, the parts are symmetrically fixed on the mounting base.

[0018] Furthermore, the distance between the two parts is greater than 180mm.

[0019] Furthermore, in step S3, the inner hole, inner cone, inner groove, outer circle and external thread at the first oil inlet hole of part one are first machined. When the first oil inlet hole of part one is completed, the machine tool table is rotated 180° and the same features at the first oil inlet hole of part two are machined.

[0020] Furthermore, in step S3, the inner hole, inner cone, inner groove, outer circle and external thread of the second oil inlet hole of part one are first machined. When the second oil inlet hole of part one is machined, the machine tool table is rotated 180° and the same features of the second oil inlet hole of part two are machined.

[0021] Furthermore, in step S3, the outer circle, inner hole and chamfer of the mounting hole of part one are first machined. When the mounting hole of part one is completed, the machine tool table is rotated 180° and the same features of the mounting hole of part two are machined.

[0022] Furthermore, in step S3, the inner hole, inner cone, inner thread and chamfer of the internal nozzle structure of part one are processed first. When the internal nozzle structure of part one is completed, the machine tool table is rotated 180° and the same features of the internal nozzle structure of part two are processed.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] 1. This invention designs a clamping method for the part, using the middle rod reference C as the transverse reference, and reference A and end face reference B as the axial reference. These three references are positioned and fixed, and other features of the part are processed in a single clamping state. This reduces reference conversion errors and helps improve the machining accuracy of the part.

[0025] 2. The design allows for the simultaneous mounting of two parts using a CNC five-axis machining center. This optimizes and merges the original five scattered and lengthy machining processes into one machining process, shortening the machining process flow by half and improving the machining efficiency of the parts.

[0026] 3. The designed fixture can clamp two parts at the same time, and the same features of the two parts can be processed in one operation. When the feature of part one is completed, the machine tool table is rotated 180° and the same features of part two are processed. The processing sequence of the feature of the parts is designed according to the characteristics of the clamping of the parts. This reduces the number of clamping operations of the parts, reduces the clamping intensity of the operator, and improves the processing efficiency of the parts. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the part reference design for the present invention;

[0028] Figure 2 This is a schematic diagram of the overall structure of the clamp of the present invention;

[0029] Figure 3 This is a top view of the overall structure of the clamp of the present invention;

[0030] Figure 4 This is a schematic diagram of the machining process sequence for the part features of the present invention;

[0031] In the above figure, 1. Fixture base plate; 2. Locating pin; 3. Screw one; 4. Mounting base; 5. Locating screw; 6. Washer; 7. Screw two; 8. Pressure plate; 9. Lifting ear; 10. Part one; 11. Part two; 12. First oil inlet hole; 13. Second oil inlet hole; 14. Mounting hole; 15. Internal nozzle structure. Detailed Implementation

[0032] To clearly illustrate the technical features of the present invention, the present invention will be described in detail below through specific embodiments and in conjunction with the accompanying drawings.

[0033] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0034] Furthermore, it should be understood in the description of this application that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as a limitation on this application. In addition, 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 application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0035] In this application, unless otherwise expressly 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 application according to the specific circumstances.

[0036] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0037] Example 1

[0038] like Figures 1-4 As shown, a method for machining a high-precision complex aero-engine fuel nozzle rod includes the following steps:

[0039] S1. Blank datum conversion: The datum A on the blank is converted to the three holes on the end face through CNC process. The datum C of the middle rod is used as the transverse datum, and the datum A and the end face datum B are used as the axial datum.

[0040] S2. Clamping parts: Design a fixture based on the positions of reference A, intermediate rod reference C and end face reference B, and position and fix the end face reference B and reference A, and press the intermediate rod reference C with the pressure plate 8.

[0041] S3. Design the machining path of the part features: The machining features of the part include the first oil inlet hole 12, the second oil inlet hole 13, the mounting hole 14 and the internal nozzle structure 15. According to the characteristics of the part clamping, the first oil inlet hole 12, the second oil inlet hole 13, the mounting hole 14 and the internal nozzle structure 15 of the two parts are machined in sequence, and the same features on the two parts are machined at once.

[0042] S4. Compile CNC machining programs: Based on the fixture dimensions, establish machining coordinates for different features of the two parts; according to the machining sequence of the part features, compile CNC machining programs for different features, with the same features of different parts programmed and machined one at a time; the specific programming methods and program codes can be implemented using existing ones.

[0043] S5. Simulate the compiled program to check for problems in the machining program and optimize the machining parameters;

[0044] S6. Start the machine tool to process the parts.

[0045] like Figure 1 and Figure 2 As shown, the part is a cast blank. The intermediate rod datum C is the machining datum. Through CNC machining, the blank datum A is converted to the three holes on the end face. The excess material of the blank datum B is removed, converting the blank datum to machining datum B. The intermediate rod datum C does not require machining and is therefore the machining datum. Figure 2 As shown, references A, B, and C of the part are the machining references of the part. The fixture is designed based on the references for positioning and fixing. Then, reference A and end face reference B are used for axial positioning and fixing. The end face reference C is fixed to the part for lateral positioning and fixing. Other features of the part are machined to ensure that the other features of the part are machined in one clamping.

[0046] like Figure 2 and Figure 3 The schematic diagram of the fixture structure shown uses the reference points A, B, and C of the parts to position and fix them. The fixture is designed to clamp and process two parts at the same time. The two parts are installed symmetrically with a distance of more than 180mm between them to prevent interference between the machine tool spindle, the machining tool and the fixture.

[0047] The fixture includes a fixture base plate 1 and mounting seats. The fixture has two mounting seats. The fixture base plate 1 has symmetrical lifting lugs 9. The two mounting seats are symmetrically arranged above the fixture base plate 1. The fixture base plate 1 has four slots for mounting screws. It is mainly used to fix the fixture as a whole to the machine tool table. The size of the fixture base plate 1 is designed to be φ350mm according to the size of the part and the clamping structure. The structural dimensions of the two mounting seats meet the size requirements of part clamping. Two parts can be installed on the fixture at the same time. After installation, they are centrally symmetrical and the two parts are at the same level, which improves the part clamping efficiency. The height of the mounting seats is based on the minimum height of 165mm required by the machine tool spindle to process the part, to prevent interference between the machine tool spindle and the fixture base plate. Each mounting seat is determined to be in the accurate position on the base plate by two locating pins 2 and connected to the fixture base plate 1 by screws 3.

[0048] When clamping parts, such as Figure 2 and Figure 3 As shown, the end face reference B and reference A are positioned and fixed by the positioning pin 2 with screws, and the part is fixed on the mounting base. The middle rod reference C is pressed by the pressure plate 8 and fixed by the screw 7. The positioning screw 5 passes through the mounting hole of the part and is positioned and fixed to the end face reference B, restricting the lateral movement of the part.

[0049] Example 2

[0050] like Figure 4 As shown, a method for machining a high-precision complex aero-engine nozzle rod further includes the following steps:

[0051] S1. Blank datum conversion: The datum A on the blank is converted to the three holes on the end face through CNC process. The datum C of the middle rod is used as the transverse datum, and the datum A and the end face datum B are used as the axial datum.

[0052] S2. Clamping parts: Design a fixture based on the positions of reference A, intermediate rod reference C and end face reference B, and position and fix the end face reference B and reference A, and press the intermediate rod reference C with the pressure plate 8.

[0053] S3. Design the machining path of the part features: The machining features of the part include the first oil inlet hole 12, the second oil inlet hole 13, the mounting hole 14 and the internal nozzle structure 15. According to the characteristics of the part clamping, the first oil inlet hole 12, the second oil inlet hole 13, the mounting hole 14 and the internal nozzle structure 15 of the two parts are machined in sequence, and the same features on the two parts are machined at once.

[0054] S4. Compile CNC machining programs: Based on the fixture dimensions, establish machining coordinates for different features of the two parts; according to the machining sequence of the part features, compile CNC machining programs for different features, with the same features of different parts programmed and machined one at a time; the specific programming methods and program codes can be implemented using existing ones.

[0055] S5. Simulate the compiled program to check for problems in the machining program and optimize the machining parameters;

[0056] S6. Start the machine tool to process the parts.

[0057] In this embodiment, the machining path for the part features is designed as follows: the main machining features of the part are as follows: Figure 4As shown, it mainly includes the features of the first oil inlet hole 12, the second oil inlet hole 13, the mounting hole 14, and the internal nozzle structure 15. Since the fixture clamps two parts at the same time, the same features of the two parts are processed at once. According to the characteristics of the part clamping, the processing sequence of the part features is designed as follows: (1) Process the features of the first oil inlet hole 12 on part 10, such as the inner hole, inner cone, inner groove, outer circle, and external thread. In order to reduce the number of times the machine tool changes during the processing, when processing the features of the first oil inlet hole 12 on part 10, the machine tool table is rotated 180°, and then the same features of the first oil inlet hole 12 on part 21 are processed; (2) Process the features of the second oil inlet hole 13 on part 10, such as the inner hole, inner cone, inner groove, outer circle, and external thread. In order to reduce the number of times the machine tool changes, when processing the features of the first oil inlet hole 12 on part 10, the machine tool table is rotated 180°, and then the same features of the first oil inlet hole 12 on part 21 are processed; (3) Process the features of the second oil inlet hole 13 on part 10, such as the inner hole, inner cone, inner groove, outer circle, and external thread. In order to reduce the number of times the machine tool changes, when processing the features of the first oil inlet hole 12 on part 10, the machine tool table is rotated 180°, and then the same features of the first oil inlet hole 12 on part 21 are processed; (4) Process the features of the second oil inlet hole 13 on part 10, such as the inner hole, inner cone, inner groove, outer circle, and external thread. When the features of the second oil inlet hole 13 on part 10 are completed, the machine tool table is rotated 180° and the same features of the second oil inlet hole 13 on part 21 are processed; (3) The features of the mounting hole 14 on part 10, such as the outer circle, inner hole, and chamfer, are processed. In order to reduce the number of machine tool changes, when the features of the mounting hole 14 on part 10 are completed, the machine tool table is rotated 180° and the same features of the mounting hole 14 on part 21 are processed; (4) The features of the internal nozzle structure 15 on part 10, such as the inner hole, inner cone, internal thread, and chamfer, are processed. In order to reduce the number of machine tool changes during the processing, when the features of the internal nozzle structure 15 on part 10 are completed, the machine tool table is rotated 180° and the same features of the internal nozzle structure 15 on part 21 are processed. The reference conversion error is reduced, the processing efficiency of the parts is greatly improved, and the processing cycle of the parts is shortened.

[0058] Example 3

[0059] In this embodiment, dedicated simulation software is used to simulate the compiled CNC program, check whether there are problems such as interference or overcutting in the machining program, and optimize the machining parameters.

[0060] Obviously, the embodiments described above are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for machining a high-precision, complex aero-engine fuel nozzle rod, characterized in that, Includes the following steps: S1. Blank datum conversion: The datum A on the blank is converted to the three holes on the end face through CNC process. The datum C of the middle rod is used as the transverse datum, and the datum A and the end face datum B are used as the axial datum. S2. Clamping parts: Two parts are clamped using a fixture. The fixture includes a fixture base plate and two mounting seats. The two mounting seats are symmetrically arranged above the fixture base plate. The two parts are symmetrically fixed on the mounting seats, and the end face reference B and reference A are positioned and fixed, and the intermediate rod reference C is pressed down. S3. Design the machining path of the part features: The machining features of the part include the first oil inlet hole, the second oil inlet hole, the mounting hole and the internal nozzle structure. The machining path is: process the first oil inlet hole, the second oil inlet hole, the mounting hole and the internal nozzle structure on the two parts in sequence. Among them, the machining of any identical feature includes: first machining the feature on the first part, then rotating the machine tool table 180°, and then machining the identical feature on the second part. S4. Compile CNC machining programs: Based on the fixture dimensions, establish machining coordinates for the different features of the two parts; compile CNC machining programs according to the machining sequence of the part features, and program and machine the same features of the two parts one at a time. S5. Simulate the compiled program to check for problems in the machining program and optimize the machining parameters; S6. Start the machine tool to process the parts.

2. The method for machining a high-precision complex aero-engine fuel nozzle rod according to claim 1, characterized in that, In step S1, the reference A, the intermediate rod reference C, and the end face reference B are all machined references.

3. The method for machining a high-precision complex aero-engine fuel nozzle rod according to claim 1, characterized in that, The height of the mounting base is the minimum height required for the machine tool spindle to process parts.

4. The method for machining a high-precision complex aero-engine fuel nozzle rod according to claim 3, characterized in that, The distance between the two parts is greater than 180mm.

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