An adaptive machining method for an oil inlet three-way seat

Abstract

The present invention relates to an adaptive machining method for an oil inlet three-way seat, comprising the following steps: installing the oil inlet three-way seat part on a pre-fixed adaptive fixture; aligning the coordinate system of the part; aiming at the instability of the casting blank state, according to the planned reference group measurement scheme: transmitting the result file obtained from the first on-line measurement back to the computer and completing the model reconstruction; according to the planned verification group measurement scheme, transmitting the result file obtained from the second on-line measurement back to the computer; importing the tool path file generated according to the theoretical model into the adaptive machining software and converting it into a tool path file suitable for the actual state; using the newly generated numerical control program to perform a machining on all features of the part except the rough long end; after measuring by professional detection methods such as measuring tools and coordinate measuring machines, qualified parts are obtained. The present invention can be applied to the optimization of machining schemes for most complex structure parts, and has strong versatility and practicability.

Description

Technical Field

[0001] The present invention relates to the technical field of aerospace numerical control machining, and particularly relates to an adaptive machining method for an oil inlet three-way seat. Background Art

[0002] Parts such as oil inlet three-way seats are typical difficult-to-machine parts of aero-engines. Due to their complex structures and the fact that the blanks are castings, etc., machining deformation or cutting chatter is likely to occur during the machining process, thus affecting the machining quality of the workpiece. The problem of its machining deformation has always been one of the key technical difficulties in the manufacture of aero-engines.

[0003] In order to improve such problems, domestic and foreign research scholars often adopt some means to improve rigidity and reduce part vibration. By using fixtures to support the machining area of the part, the overall rigidity of the part is improved; by increasing the machining processes and reducing the material removal amount per process, the deformation generated during the machining of the part is reduced.

[0004] For the machining scheme of oil inlet three-way seat parts of aero-engines, it is often the case that process personnel rely on their own work experience to formulate the overall machining scheme of the parts. The existing machining scheme decomposes the machining content to be processed at each part into each process one by one, and each process requires re-clamping of the part, resulting in the continuous accumulation of clamping errors during the machining process of the part, which has a great impact on the machining quality of the part. At the same time, this machining scheme also leads to a long process route and a very large variety of fixtures to be used, which is not conducive to the economy of manufacturing. Summary of the Invention

[0005] To solve the above technical problems, the present invention provides an adaptive machining method for an oil inlet three-way seat; the specific technical solution is as follows:

[0006] An adaptive machining method for an oil inlet three-way seat, comprising the following steps:

[0007] Step 1, install the oil inlet three-way seat part on a pre-fixed adaptive fixture, and tighten the three-jaw chuck;

[0008] Step 2, use the machine tool to measure the part to align the coordinate system, and roughly align X0, Y0, Z0, A0, and C0 respectively;

[0009] Step 3, aiming at the instability of the casting blank state of the oil inlet three-way seat, use the allowance optimization module to perform adaptive machining on it, and to meet the requirements of the wall thickness size and uniformity of the part, plan and formulate a reference group measurement scheme for the part;

[0010] Step 4, according to the planned reference group measurement scheme, generate an on-line measurement numerical control program in the adaptive machining software, and perform the first on-line measurement on the part;

[0011] Step 5, after transmitting the result file obtained from the first online measurement back to the computer and completing the reconstruction of the part model, plan the measurement scheme for the verification group;

[0012] Step 6, generate an online measurement NC program in the adaptive machining software according to the planned measurement scheme for the verification group, and conduct a second online measurement on the part;

[0013] Step 7, transmit the result file obtained from the second online measurement back to the computer, verify the part model reconstructed for the first time, and obtain a model closer to the actual state of the part;

[0014] Step 8, import the tool path file generated based on the part theoretical model into the adaptive machining software and convert it into a tool path file suitable for the actual state;

[0015] Step 9, use the newly generated NC program to machine all features of the part except the rough long end once;

[0016] Step 10, after measuring with professional inspection methods such as measuring tools and coordinate measuring machines, obtain qualified parts.

[0017] In the preferred embodiment of the adaptive machining method for the oil inlet three-way seat, in step one, the adaptive fixture includes a fixture chassis, a three-jaw chuck, an auxiliary support, a tightening screw, a plastic screw, and a stop screw; the three-jaw chuck is arranged on the fixture chassis, and the rough long end of the oil inlet three-way seat is placed inside the three-jaw chuck;

[0018] The auxiliary support is L-shaped, with an installation groove on the upper end surface, a screw hole is provided in the installation groove, and the auxiliary support is arranged on the fixture chassis on one side of the three-jaw chuck; the tightening screw passes through the screw hole and abuts against the oil inlet three-way seat;

[0019] A long hole is provided on the screw rod of the tightening screw, the plastic screw passes through the screw hole at the bottom of the installation groove and extends out of the installation groove through the long hole, the slender end of the oil inlet three-way seat is placed above the auxiliary support device and is abutted by the plastic screw, and the stop screw is provided to prevent the tightening screw knob from overtraveling.

[0020] In the preferred embodiment of the adaptive machining method for the oil inlet three-way seat, in step two, set the machine tool coordinate system as G54, and the reference for each axis is: (1) Z0: Set the uppermost end of the outer circle A surface of the workpiece as Z + 12; (2) X0, Y0: Align the cylindrical surface B of the workpiece or the cylindrical surface on the fixture that mates with the cylindrical surface C of the workpiece at the machine tool rotation center; (3) C0: Straighten the outer circle A surface of the workpiece along the X direction to ensure that the runout is not greater than 0.05. After straightening, the D surface is located on the positive X direction of the machine tool.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects:

[0022] The present invention first proposes an adaptive machining method for an oil inlet three-way seat, which optimizes the machining plan during the part machining process based on adaptive machining technology, and can improve the machining quality of the part while having better efficiency and economy.

[0023] Machining tests show that: according to the method of the present invention to optimize the machining plan, the number of processes of the part after optimization is reduced by more than 60%, the number of tooling is reduced by about 60%, the number of times of re-clamping the part is reduced by about 50%, the process route is greatly shortened, the manufacturing cost is greatly reduced, and the machining quality of the part is also improved to a certain extent.

[0024] The implementation of this method not only ensures the machining quality of oil inlet three-way seat parts of multiple models, but also can be applied to the optimization of machining plans for most complex structure parts, with strong versatility and practicability, creating huge economic benefits while enhancing the core innovation ability and R & D efficiency of enterprises. Description of the Drawings

[0025] Figure 1 is the flow chart of the present invention;

[0026] Figure 2 is the schematic diagram of the clamping and alignment of the coordinate system of the oil inlet three-way part;

[0027] Figure 3 is the schematic diagram of the measurement plan of the reference detection group;

[0028] Figure 4 is the simulation schematic diagram of the measurement plan of the reference detection group;

[0029] Figure 5 is the simulation schematic diagram of the measurement plan of the verification detection group;

[0030] Figure 6 is the schematic diagram of the comparison of the two online measurement results;

[0031] Figure 7 is the schematic diagram of the comparison before and after the regeneration of the tool path; where Pre-Path is the original tool path and Later-Path is the tool path after adaptive adjustment.

[0032] In the figure: 1 is the oil inlet three-way seat, 2 is the three-jaw chuck, 3 is the fixture base, 4 is the top screw, 5 is the auxiliary support, 6 is the plastic screw, and 7 is the stop screw. Detailed Embodiments

[0033] The following will describe the present invention in detail in conjunction with the attached Figure 1-7 The protection scope of the present invention is not limited by the drawings.

[0034] Embodiment 1

[0035] The present invention selects parts such as the oil inlet three-way seat in an aeroengine for adaptive machining optimization of the machining plan. Due to the characteristics of weak rigidity and casting blank of such parts, deformation or vibration is likely to occur during part machining, thus affecting the machining quality of the workpiece. The overall structure of the workpiece has multiple slender overhanging features, and there are holes of different sizes and precisions on each end face. Among them, the smallest oil injection hole has a diameter of only 1.45 mm, and the holes communicate with each other. The machining content is very complex, resulting in a total of 32 processes in the process route, 11 fixtures need to be used, and the number of times of clamping and alignment is as many as 13 times. Therefore, taking the machining content of the mounting plate end of the part as the research object, the machining plan of the part is optimized by using adaptive machining technology. The following will focus on the optimization of the machining plan for the mounting plate end of the part and further explain the present invention in combination with Attachments Figure 1-7 and embodiments

[0036] An adaptive machining method for an oil inlet three-way seat includes the following steps:

[0037] Step 1, place the adaptive fixture on the machine tool workbench, and place the slender end of the oil inlet three-way seat 1 of the adaptive fixture in the auxiliary support X-axis direction; if it is impossible to machine the oil inlet three-way seat 1 due to the limitation of the machine tool spindle stroke, a tooling element such as a square box that does not affect the machining of the oil inlet three-way seat 1 can be used to pad up the fixture, and the square box is firmly connected to the workbench and the fixture is firmly connected to the square box.

[0038] The adaptive fixture includes a fixture chassis 3, a three-jaw chuck 2, an auxiliary support 5, a top screw 4, a plastic screw 6, and a stop screw 7; the three-jaw chuck 2 is arranged on the fixture chassis 3, and the thick and long end of the oil inlet three-way seat 1 is placed in the three-jaw chuck 2;

[0039] The auxiliary support 5 is L-shaped, with a mounting groove on the upper end face, a screw hole is arranged in the mounting groove, and the auxiliary support 5 is arranged on the fixture chassis 3 on one side of the three-jaw chuck 2; the top screw 4 passes through the screw hole and abuts against the oil inlet three-way seat 1;

[0040] A long hole is arranged on the screw rod of the top screw 4, the plastic screw 6 passes through the screw hole at the bottom of the mounting groove and extends out of the mounting groove through the long hole, the slender end of the oil inlet three-way seat 1 is placed above the auxiliary support 5 and is abutted by the plastic screw 6, and the stop screw 6 is arranged to prevent the top screw 4 from over-rotating.

[0041] During assembly, the two plastic screws 6 on the adaptive fixture are removed in advance to prevent the thick and long end of the oil inlet three-way seat 1 from being misaligned with the Z-axis of the machine tool during the clamping process; use a special wrench to release the three-jaw chuck 2, place the thick and long end of the oil inlet three-way seat 1 into the three-jaw chuck 2, place the slender end above the auxiliary support 5, tighten the three-jaw chuck 2 to fix the long end of the oil inlet three-way seat 1, and use the plastic screw 6 to support the slender end of the oil inlet three-way seat 1.

[0042] 2) Set the machine tool coordinate system as G54, and the reference for each axis is as follows: (1) Z0: Set the uppermost end of the outer circle A surface of the workpiece as Z + 12; (2) X0, Y0: Align the cylindrical surface B of the workpiece or the cylindrical surface on the fixture that mates with the cylindrical surface C of the workpiece at the center of rotation of the machine tool; (3) C0: Straighten the outer circle A surface of the workpiece along the X direction, ensuring that the runout is no greater than 0.05. After straightening, the D surface is located on the positive X direction of the machine tool, as Figure 2 shown.

[0043] 3) The blank of the oil inlet three-way seat is a casting. Due to certain errors after casting, the allowance distribution is uneven. Therefore, it is necessary to optimize the analysis of the blank allowance; according to the requirements of on-line measurement and calibration, use the method of selecting points with the mouse to take points and plan the measurement scheme for the reference detection group;

[0044] When planning the measurement scheme for the reference group, on the one hand, consider the allowance distribution problem of the blank of the oil inlet three-way seat, and on the other hand, align the reference of the oil inlet three-way seat; therefore, select the large-end cylindrical surface and the cylindrical surface at the end where the oil injection hole is located as the measurement positions to quickly find the positions of the centerlines of the two cylindrical surfaces and the intersection position of the centerlines. Optimize the blank allowance of the oil inlet three-way seat based on the detection results to ensure that the blank can accommodate the entire oil inlet three-way seat and the allowance distribution is relatively uniform; the measurement point planning is as Figure 3 shown, and the measurement path simulation and interference check of the oil inlet three-way seat are as Figure 4 shown, and there is no interference in the detection path.

[0045] 4) Use the adaptive machining software to generate a numerical control program from the measurement scheme of the reference group and transfer it to the machine tool through machine tool communication. Perform the first on-line measurement of the oil inlet three-way seat at the detection speed when calibrating the probe.

[0046] 5) After the machine tool performs an on-line measurement of the oil inlet three-way seat, it will automatically generate a measurement result file, which can also be transmitted back to the computer through machine tool communication; import the measurement data into the adaptive machining software, and the software will automatically reconstruct the actual model of the part according to the measurement results and display the offset of the part in the X, Y, and Z axis directions and the angle;

[0047] To verify whether the reconstructed model of the oil inlet three-way seat is accurate and whether the deviation corrected by the reference group meets the machining accuracy requirements, it is necessary to plan a calibration group to check the detection accuracy; the detection path planning of the calibration group is basically the same as that of the reference group, and three measurement points are added on the upper cylindrical surface to verify that the part model can meet the requirement of uniform allowance distribution after being transformed according to the detection data of the reference group. The simulation of the calibration group planning scheme is as Figure 5 shown.

[0048] 6) Use adaptive machining software to generate a numerical control program from the measurement plan of the planning group and transfer it to the machine tool through machine tool communication; perform a second on-line measurement on the oil inlet three-way seat at the detection speed during probe calibration.

[0049] 7) Similar to the first on-line measurement, the result data of the second on-line measurement is also imported into the adaptive machining software, and the part reconstruction model is corrected twice; if the results of the two reconstructed models of the oil inlet three-way seat are consistent, the reconstructed model of the oil inlet three-way seat can be used for subsequent adaptive machining; otherwise, the measurement plan for the oil inlet three-way seat needs to be re-planned until the results of the two model reconstructions are consistent, as Figure 6 shown.

[0050] 8) In CAM software such as UG, generate a tool path file (.cls file) from the tool path prepared according to the original theoretical model of the part and export it; then import these tool path files into the adaptive machining software, and use the built-in adaptive function of the software to regenerate the tool path to a tool path suitable for the actual state of the part, and compensate the offset values in each direction obtained from the on-line measurement of the part into the new tool path, as Figure 7 shown.

[0051] 9) After being processed by the software-specific post-processing file, generate the numerical control machining program corresponding to the machine tool, transfer it to the machine tool through machine tool communication and machine the oil inlet three-way seat.

[0052] 10) Submit the machined oil inlet three-way seat to professional inspectors, and inspect the machined oil inlet three-way seat according to the inspection method on the process document; if all the machined features of the oil inlet three-way seat are qualified, this machining plan can be solidified; otherwise, the on-line measurement plan needs to be re-adjusted until the part machining is qualified.

Claims

1. An adaptive machining method for an oil inlet three-way seat, characterized in that: It includes the following steps: Step 1: Install the oil inlet three-way seat onto the pre-fixed adaptive fixture and tighten the three-jaw chuck; Step 2: Use the machine tool indicator to align the coordinate system of the oil inlet three-way seat, and roughly align X0, Y0, Z0, A0, and C0 respectively; Step 3: Due to the instability of the rough casting state of the oil inlet three-way seat, use the allowance optimization module to perform adaptive machining on it. To meet the requirements of the wall thickness dimension and uniformity of the oil inlet three-way seat, plan and formulate a measurement plan for the reference group of the oil inlet three-way seat; Step 4: According to the planned measurement plan for the reference group, generate an on-line measurement NC program in the adaptive machining software and perform the first on-line measurement on the oil inlet three-way seat; Step 5: Send the result file obtained from the first on-line measurement back to the computer and complete the reconstruction of the part model, showing the offset of the part in the X, Y, and Z axis directions and the angle, and plan the verification group measurement plan; The detection path planning of the verification group is basically the same as that of the reference group, and three measurement points are added on the upper end cylindrical surface to verify that the part model can meet the requirement of uniform allowance distribution after being transformed according to the detection data of the reference group; Step 6: According to the planned measurement plan for the verification group, generate an on-line measurement NC program in the adaptive machining software and perform the second on-line measurement on the oil inlet three-way seat; Step 7: Send the result file obtained from the second on-line measurement back to the computer, import the result data of the second on-line measurement into the adaptive machining software, and perform secondary correction on the reconstructed part model; verify the first reconstructed part model. If the results of the two reconstructed models of the oil inlet three-way seat are the same, the reconstructed model of the oil inlet three-way seat can be used for subsequent adaptive machining; Otherwise, it is necessary to re-plan the measurement plan of the oil inlet three-way seat until the results of the two model reconstructions are the same; Step 8: Import the tool path file generated according to the theoretical model of the oil inlet three-way seat into the adaptive machining software and convert it into a tool path file suitable for the actual state; Step 9: Use the newly generated NC program to perform a machining on all features of the oil inlet three-way seat except the rough long end; Step 10: After measurement by professional detection methods such as measuring tools and coordinate measuring machines, a qualified oil inlet three-way seat is obtained.

2. The adaptive machining method of an oil inlet three-way seat according to claim 1, characterized in that: In Step 1, the adaptive fixture includes a fixture chassis, a three-jaw chuck, an auxiliary support, a top screw, a plastic screw, and a stop screw; the three-jaw chuck is arranged on the fixture chassis, and the rough long end of the oil inlet three-way seat is placed inside the three-jaw chuck; The auxiliary support is L-shaped, with an installation groove on the upper end surface, and a screw hole is arranged in the installation groove. The auxiliary support is arranged on the fixture chassis on one side of the three-jaw chuck; the top screw passes through the screw hole and abuts against the oil inlet three-way seat; A long slot is arranged on the screw rod of the top screw, and the plastic screw passes through the screw hole at the bottom of the installation groove and extends out of the installation groove through the long slot. The slender end of the oil inlet three-way seat is placed above the auxiliary support device and is abutted by the plastic screw; the stop screw is arranged to prevent the top screw from over-rotating.

Images