A method for processing a blade body after welding deformation of a hollow web plate of an aero-engine fan

Abstract

The application discloses an aero-engine fan hollow support plate welding deformation after blade machining method, including sequentially implemented S1 component pre-positioning and centering clamping, S2 blade profile rough milling, S3 blade profile and wall thickness measurement, S4 reference offset calculation and reference correction and S5 blade profile finishing. The application aims at the reference failure, profile profile degree and wall thickness size out-of-control problem caused by hollow support plate diffusion welding deformation, designs a method of re-reference, closed-loop compensation processing, realizes the reference reconstruction of the assembly after welding, and ensures the consistent coordination accuracy of the profile and the wall thickness.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine manufacturing technology, specifically relating to a processing method for deformation compensation and benchmark correction of a hollow fan support plate assembly after welding. Background Technology

[0002] The hollow fan support plate is a core load-bearing component of the aero-engine flow channel. It mostly adopts a thin-walled welded structure of titanium alloy. The inner cavity of two pairs of half blanks is first processed, welded, and then the components are processed and formed.

[0003] like Figure 1 As shown, the hollow fan support plate assembly is welded. The hollow fan support plate assembly includes a blade located in the middle part. There is a mounting plate at each of the left and right ends of the blade. One mounting plate has two positioning pin holes, and the other mounting plate has one positioning pin hole. The axes of the three positioning pin holes are parallel, and the upper and lower end faces of each mounting plate serve as clamping surfaces.

[0004] Hollow fan support plates are characterized by poor rigidity, thin walls, and complex structures. Uneven heat and pressure input during diffusion welding can easily lead to irregular warping and torsional deformation of the welded components. This causes a shift in the relative position between the pre-set machining datum and the blade's inner cavity, resulting in the complete loss of the original datum. In subsequent five-axis milling of the blade, using this failed datum for positioning will lead to out-of-tolerance blade profile and uneven wall thickness distribution, exceeding the lower limit of design requirements and resulting in an extremely high scrap rate. To address these industry pain points, this invention proposes a welding component processing method based on physical datum correction. Summary of the Invention

[0005] The purpose of this invention is to address the problems of datum failure, surface profile and wall thickness loss caused by diffusion welding deformation of hollow support plates, and to provide a method for datum reconstruction and closed-loop compensation processing, so as to realize the reconstruction of the datum of the component after welding and ensure the consistency of the surface profile and wall thickness coordination accuracy.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for machining the blade of an aero-engine fan after welding deformation of the hollow support plate includes: S1, Component pre-positioning and sub-center clamping: After removing surface oil from the welded hollow fan support plate assembly, it is installed on the rotary center of a four-axis linkage machining center. Two sets of symmetrically arranged self-centering vises are used to clamp the clamping surfaces of the mounting plates at both ends of the hollow fan support plate assembly. The self-centering vises are controlled to perform synchronous centering to determine the Y coordinate of the hollow fan support plate assembly. The X and Z coordinates are then determined by the three reserved positioning pin holes on the mounting plates at both ends of the hollow fan support plate assembly. The initial machining coordinate system is established with the common rotary center of the two sets of self-centering vises as the origin. S2, rough milling of blade profile: Using the initial machining coordinate system established in S1 as the positioning reference, the blade surface is rough milled through four-axis linkage machining, leaving a fine milling allowance; S3, Blade profile and wall thickness measurement: A three-coordinate contact probe is used to perform a full-surface scanning measurement of the blade profile to obtain the blade profile contour. An ultrasonic thickness gauge was used to measure the wall thickness of the blade in the basin and back directions at each measurement section of the blade. S4, Base offset calculation and base correction: Based on the blade profile contour results measured by the coordinate measuring machine in S3, determine the tool compensation value h; Based on the wall thickness measurements in S3, compare the wall thickness dimensions of the same cross section on the blade in the basin direction and the back direction. The wall thickness dimension of the thicker side is denoted as C. 大 The wall thickness on the thinner side is denoted as C. 小 Calculate the wall thickness deviation value a1=C for each section. 大1 -C 小1 a2=C 大2 -C 小2 ...a n =C 大n -C 小n n is a natural number, corresponding to the section number; The wall thickness deviation is analyzed and calculated to obtain the trimming amount of the clamping surface. The trimming amount is then used to correct the clamping surfaces of the mounting plates at both ends of the fan hollow support plate assembly, which serves as the machining reference surface. S5, blade profile precision machining: The hollow fan support plate assembly, after the machining reference surface has been corrected, is installed on the rotary center of a five-axis linkage machining center. Two sets of symmetrically arranged self-centering vises are used to clamp the mounting plate clamping surfaces at both ends of the hollow fan support plate assembly. The self-centering vises are controlled to center synchronously, thereby determining the Y coordinate by centering the hollow fan support plate assembly left and right. The X and Z coordinates are then determined by the three reserved positioning pin holes on the mounting plates at both ends of the hollow fan support plate assembly. The finishing coordinate system is established with the common rotary center of the two sets of self-centering vises as the origin, and then the blade profile is finished.

[0007] As one solution: In S3, when using an ultrasonic thickness gauge to measure the wall thickness of the blade in the basin direction and the back direction at each measurement section of the blade, a measurement point is taken on each side of the basin direction and the back direction, and the measurement points are symmetrical about the arc in the blade section. The wall thickness of the measurement point in the basin direction is taken as the wall thickness of the basin direction, and the wall thickness of the measurement point in the back direction is taken as the wall thickness of the back direction. Alternatively, when using an ultrasonic thickness gauge to measure the wall thickness of the blade in the basin and back directions at each measurement section, take an equal number of measurement points on both the basin and back sides, and group the basin and back measurement points together in pairs. The two measurement points in each group are symmetrical about the arc in the blade section. Take the average wall thickness of the multiple measurement points in the basin direction as the basin wall thickness, and take the average wall thickness of the multiple measurement points in the back direction as the back wall thickness.

[0008] As one approach: In S3, when using an ultrasonic thickness gauge to measure the wall thickness of the blade in the basin and back directions at each measurement section, the actual wall thickness at each position on the measurement section of the blade is obtained by measuring along the normal direction of the blade profile.

[0009] As one approach: In S4, for the wall thickness deviation values ​​of each blade measurement section, when the wall thickness results of all measurement sections are either thicker in the basin direction than in the back direction or thinner in the basin direction than in the back direction, and the maximum deviation value a max -Minimum deviation value a min When ≤0.05mm, a max and a min These are the sequence of wall thickness dimensions of the measured cross-section (a1, a2, ..., a...). n The maximum and minimum values ​​in the range are taken as the average deviation a = (a1 + a2 + ... + a) / ( ... n ) / 2 is used as the trimming amount to correct the clamping surfaces of the mounting plates at both ends, which are the machining reference surfaces and correspond to the side with thicker blade wall, to obtain the machining reference plane.

[0010] As one approach: In S4, regarding the wall thickness deviation values ​​of each blade measurement section, when the wall thickness results of each measurement section differ significantly (the thicker side is not entirely basin-oriented, or in other words, there are measurement sections where the basin-oriented side is thicker than the back-oriented side, and also measurement sections where the back-oriented side is thicker than the basin-oriented side), the intermediate measurement sections other than the first and last sections are ignored, and only the first and last measurement sections are used as references, with a = (C 大1 -C 小1 ) / 2 is used as the adjustment amount to correct the clamping surface on the mounting plate closest to the first measurement section, corresponding to the side with the thicker blade wall. Take a = (C 大n -C 小n The amount of 1 / 2 is used to correct the clamping surface on the mounting plate closest to the tail measurement section, corresponding to the side with the thicker blade wall.

[0011] As one possible solution: In S1, the positioning accuracy of the self-centering vise is 0.01mm.

[0012] Compared with the prior art, the present invention fundamentally solves the problem of reference loss caused by welding deformation, so that the machining reference is completely matched with the actual position of the cavity inside the blade. The present invention has high clamping and positioning accuracy. By correcting the positioning datum of the precision machining, subsequent clamping does not require repeated measurement and fitting, which greatly improves the processing efficiency and consistency of mass production of hollow fan support plate components, and the tooling has strong adaptability.

[0013] The processing method of the present invention has strong versatility and wide applicability.

[0014] The processing method of this invention can be adapted to the processing of welding components such as hollow support plates and guide vanes of aero engines of different models and structures. Attached Figure Description

[0015] Figure 1 This is a model diagram of the hollow fan support plate assembly after welding in this invention; Figure 2 This is a schematic diagram of the rough milling of the blade profile in this invention; Figure 3 This is a schematic diagram illustrating the use of a three-coordinate measuring machine (TCM) system to measure the profile of the blade in this invention. Figure 4 This is a schematic diagram of the measurement points used in this invention to measure the blade wall thickness using an ultrasonic thickness gauge. Figure 5 This is a schematic diagram of the physical reference correction surface of the hollow fan support plate in this invention; Figure 6 This is a schematic diagram of the precision milled blade profile in this invention. Detailed Implementation

[0016] The present invention will be further described below with reference to specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All modifications, substitutions and alterations made based on ordinary technical knowledge and common practices in the art without departing from the above-described technical concept of the present invention are included within the scope of the present invention.

[0017] like Figures 2-6 As shown, this invention provides a method for machining the blade of an aero-engine fan after welding deformation of the hollow support plate, specifically including the following steps: S1, Component pre-positioning and sub-center clamping: After removing surface oil from the welded hollow fan support plate assembly, it is installed on the rotary center of a four-axis machining center. Two sets of symmetrically arranged (because the upper and lower end faces of the mounting plates at both ends of the hollow fan support plate assembly are clamping surfaces, a set of self-centering vises is needed at each end to clamp it, ensuring that the symmetry center of the two clamping surfaces of the two sets of self-centering vises is the same plane) high-precision (positioning accuracy of the self-centering vise ≤ 0.01mm) self-centering vises are used to clamp the clamping surfaces of the mounting plates at both ends of the assembly (see...). Figure 2The initial clamping surface is used to pre-calibrate the coaxiality of the two sets of self-centering vises to within 0.01mm. The self-centering vises are controlled to perform synchronous centering, with the clamping force set to 12MPa to prevent excessive force from deforming the fan hollow support plate assembly mounting plate. This achieves left-right centering of the fan hollow support plate assembly, determining the Y-coordinate (left-right centering refers to: such as...). Figure 5 As shown, if the thickness between the upper and lower clamping surfaces of the mounting plates at both ends of the hollow fan support plate assembly is H, then H / 2 is half of the thickness, which is the middle position. At this time, H / 2 is taken as the zero point of the Y-axis of the Y coordinate. The X and Z coordinates are determined by the three reserved positioning pin holes on the mounting plate (the center of the three positioning pin holes, together with the zero point of the Y-axis, determines the XZ plane, and the direction perpendicular to the XZ plane is the Y-axis direction. The three positioning pin holes correspond to three points in the XZ plane. Among them, the two points corresponding to the two positioning pin holes on the same mounting plate form a straight line as the X-axis, and the perpendicular line from the point corresponding to the positioning pin hole on the other mounting plate to the X-axis is the Z-axis). The initial machining coordinate system is established with the common rotation center of the two sets of self-centering vises as the origin. S2, rough milling of blade profile: Using the initial machining coordinate system as the positioning reference, a Ø12R1.5 carbide end mill is used to rough mill the blade profile of the hollow support plate of the fan through a four-axis linkage machining method. A fine milling allowance of 0.4mm is reserved on each side to ensure that the uniformity deviation of the blade profile allowance after rough milling does not exceed 0.1mm. S3, Blade profile and wall thickness measurement: After machining, the hollow fan support plate is removed from the milling machine, and the blade profile and blade wall thickness are measured respectively: Blade profile measurement: A three-coordinate contact probe is used to perform a full-surface scan measurement of the blade's outer profile to obtain the blade profile values. (See attached image.) Figure 3 The measurement objects were 28 sections numbered I to XXVIII on the blade. Figure 3 The numbers inside the rectangular boxes represent the cross-sectional distances of each section of the blade, in mm. The solid black dots in the ellipses represent the starting positions of the cross-sections or coordinates. Blade wall thickness measurement: Using an ultrasonic thickness gauge, three measurement points are selected on each measurement section of the blade in both the basin and back directions (the number can be adjusted appropriately according to the complexity of the fan hollow support plate profile, with at least one measurement point in each direction). The measurement points on both sides of the basin and back directions should be as symmetrical as possible (symmetric about the mid-arc of the blade section). The actual wall thickness data at each location on the blade is obtained by measuring along the normal direction of the blade profile. Figure 4N1 to N5 represent five measurement sections for the blade wall thickness. The numbers within the rectangles represent the distance between the measurement sections, and the solid black circles represent the locations where the wall thickness is measured. Numbers 1 to 15 represent 15 measurement points on the five measurement sections, with 15 measurement points each in the basin and back directions. For example, when measuring the wall thickness at measurement section N1, if the measurement points are 1, 2, and 3, first measure the wall thickness at the three measurement points in the basin direction of N1, and take the average of these three measurements as the basin-direction wall thickness. Then measure the wall thickness at the three locations in the back direction that are symmetrical to measurement points 1, 2, and 3, and take the average of these three measurements as the back-direction wall thickness.

[0018] S4, Base offset calculation and base correction: Based on the coordinate measuring machine (CMM) measurement results, the tool compensation value h is determined (the blade profile of the first fan hollow support plate assembly can be fixed after the adjustment is qualified, without the need for secondary adjustment); the tool compensation value h refers to the compensation for the length of the CMM tool. For example, when the blade profile dimension is too large, a deeper milling is required. In this case, the adjusted tool compensation value h should be negative, so that the theoretical tool length is less than the actual length, allowing for a deeper cut during machining in the equipment.

[0019] Based on the wall thickness measurements, compare the wall thickness dimensions of the same cross section on the leaf blade in the pot-side and back-side directions. The wall thickness dimension of the thicker side is denoted as C. 大 The wall thickness on the thinner side is denoted as C. 小 For each of the five measurement sections N1 to N5, calculate the wall thickness deviation value a1=C. 大1 -C 小1 a2=C 大2 -C 小2 a3=C 大3 -C 小3 a4=C 大4 -C 小4 a5=C 大5 -C 小5 For example, after measuring the N1 section in S3, two wall thickness dimensions were obtained: the basin-direction and the back-direction. Comparing the two dimensions, assuming the basin-direction is thicker than the back-direction, then the basin-direction thickness is C. 大1 The back is C 小1 The thickness deviation value of the N1 measured section is a1=C 大1 -C 小1 .

[0020] When the wall thickness measurements of the five cross-sections all show either a thicker or thinner profile in the basin direction compared to the back direction, and a max -a min When ≤0.05mm, a max =max{ a1,a2,a3,a4,a5}, a min=min{ a1,a2,a3,a4,a5}, the average deviation a = (a1+a2+a3+a4+a5) / 2 can be taken as the adjustment amount. The clamping reference planes at both ends of the thicker side of the fan hollow support plate assembly blade are then corrected. The reference plane (e.g.) Figure 5 The two red clamping surfaces (which are on the same side as the thicker blade wall surface) are removed by milling to a depth of a.

[0021] When the wall thickness results of the five measurement sections differ significantly (including sections where the wall thickness is greater in the basin direction than in the back direction, and sections where the back thickness is greater than in the basin direction), measurement sections a2, a3, and a4 can be ignored. The first section a1 and the last section a5 are taken as references, and the adjustment amounts for the first section a1 and the last section a5 are calculated respectively. The adjustment amount for the first section a1 is a = (C... 大1 -C 小1 ) / 2, the trimming amount of the tail section a5 is a = (C 大n -C 小n ) / 2. For the trimming amount of the first section a1, select the mounting plate closest to the first section a1 among the two mounting plates. Based on the wall thickness measurement results of the first section a1, select the mounting plate clamping surface on the same side as the thicker side of the first section a1 (for example, if the thickness in the basin direction is greater than that in the back direction, then select the clamping surface on the same side as the basin direction). Remove a = (C) from the clamping surface using milling. 大1 -C 小1 After obtaining the reference plane by ) / 2, similarly, for the trimming amount of the tail section a5, select the mounting plate that is closest to the tail section a5 among the two mounting plates. Based on the wall thickness measurement results of the tail section a5, select the clamping surface of the mounting plate on the same side as the side with the thicker wall thickness of the tail section a5. Use milling to remove a=(C) from the clamping surface. 大5 -C 小5 The reference plane is obtained after dividing by 2.

[0022] S5, blade profile precision machining: After the reference plane (clamping surface) is corrected, the hollow fan support plate assembly is installed on the rotary center of a five-axis linkage machining center. Two sets of symmetrically arranged high-precision self-centering vises are used to clamp the clamping surfaces of the mounting plates at both ends of the hollow fan support plate assembly. The coaxiality of the two sets of self-centering vises is corrected to within 0.01mm beforehand. The self-centering vises are controlled to center synchronously, and the clamping force is set to 12Mpa to avoid excessive clamping force that could deform the mounting plates. This achieves left-right centering of the hollow fan support plate assembly and determines the Y coordinate. The X and Z coordinates are determined by the three reserved positioning pin holes on the two mounting plates. A finishing coordinate system is established with the common rotary center of the two sets of self-centering vises as the origin. Finally, the blade profile is finished.

[0023] Contents not described in detail in this specification are prior art known to those skilled in the art. Although illustrative specific embodiments of the invention have been described above to facilitate understanding by those skilled in the art, it should be understood that the invention is not limited to the scope of the specific embodiments. Various modifications are readily apparent to those skilled in the art as long as they fall within the spirit and scope of the invention as defined and determined by the appended claims, and all inventions utilizing the concept of this invention are protected.

Claims

1. A method for machining the blade of an aero-engine fan after welding deformation of the hollow support plate, characterized in that, include: S1, Component pre-positioning and sub-center clamping: After removing surface oil from the welded hollow fan support plate assembly, it is installed on the rotary center of a four-axis linkage machining center. Two sets of symmetrically arranged self-centering vises are used to clamp the clamping surfaces of the mounting plates at both ends of the hollow fan support plate assembly. The self-centering vises are controlled to perform synchronous centering to determine the Y coordinate of the hollow fan support plate assembly. The X and Z coordinates are then determined by the three reserved positioning pin holes on the mounting plates at both ends of the hollow fan support plate assembly. The initial machining coordinate system is established with the common rotary center of the two sets of self-centering vises as the origin. S2, rough milling of blade profile: Using the initial machining coordinate system established in S1 as the positioning reference, the blade surface is rough milled through four-axis linkage machining, leaving a fine milling allowance; S3, Blade profile and wall thickness measurement: A three-coordinate contact probe is used to perform a full-surface scanning measurement of the blade profile to obtain the blade profile contour. An ultrasonic thickness gauge was used to measure the wall thickness of the blade in the basin and back directions at each measurement section of the blade. S4, Base offset calculation and base correction: Based on the blade profile contour results measured by the coordinate measuring machine in S3, determine the tool compensation value h; Based on the wall thickness measurements in S3, compare the wall thickness dimensions of the same cross section on the blade in the basin direction and the back direction. The wall thickness dimension of the thicker side is denoted as C. 大 The wall thickness of the thinner side is denoted as C. 小 Calculate the wall thickness deviation value a1=C for each section. 大1 -C 小1 a2=C 大2 -C 小2 ...a n =C 大n -C 小n n is a natural number, corresponding to the section number; The wall thickness deviation is analyzed and calculated to obtain the trimming amount of the clamping surface. The trimming amount is then used to correct the clamping surfaces of the mounting plates at both ends of the fan hollow support plate assembly, which serves as the machining reference surface. S5, blade profile precision machining: The hollow fan support plate assembly, after the machining reference surface has been corrected, is installed on the rotary center of a five-axis linkage machining center. Two sets of symmetrically arranged self-centering vises are used to clamp the mounting plate clamping surfaces at both ends of the hollow fan support plate assembly. The self-centering vises are controlled to center synchronously, thereby determining the Y coordinate by centering the hollow fan support plate assembly left and right. The X and Z coordinates are then determined by the three reserved positioning pin holes on the mounting plates at both ends of the hollow fan support plate assembly. The finishing coordinate system is established with the common rotary center of the two sets of self-centering vises as the origin, and then the blade profile is finished.

2. The method for processing the blade of an aero-engine fan after welding deformation of the hollow support plate according to claim 1, characterized in that: In S3, when using an ultrasonic thickness gauge to measure the wall thickness of the blade in the basin direction and the back direction at each measurement section of the blade, a measurement point is taken on each side of the basin direction and the back direction, and the measurement points are symmetrical about the arc in the blade section. The wall thickness of the measurement point in the basin direction is taken as the wall thickness of the basin direction, and the wall thickness of the measurement point in the back direction is taken as the wall thickness of the back direction. Alternatively, when using an ultrasonic thickness gauge to measure the wall thickness of the blade in the basin and back directions at each measurement section, take an equal number of measurement points on both the basin and back sides, and group the basin and back measurement points together in pairs. The two measurement points in each group are symmetrical about the arc in the blade section. Take the average wall thickness of the multiple measurement points in the basin direction as the basin wall thickness, and take the average wall thickness of the multiple measurement points in the back direction as the back wall thickness.

3. The method for machining the blade of an aero-engine fan after welding deformation of the hollow support plate according to claim 1, characterized in that: In S3, when the ultrasonic thickness gauge is used to measure the wall thickness of the blade in the basin direction and the back direction at each measurement section of the blade, the actual wall thickness at each position on the measurement section of the blade is obtained by measuring along the normal direction of the blade profile.

4. The method for processing the blade of an aero-engine fan after welding deformation of the hollow support plate according to claim 1, characterized in that: In step S4, for the wall thickness deviation values ​​of each blade measurement section, when the wall thickness results of all measurement sections are either thicker in the basin direction than in the back direction or thinner in the basin direction than in the back direction, and the maximum deviation value a max -Minimum deviation value a min When ≤0.05mm, a max and a min These are the sequence of wall thickness dimensions of the measured cross-section (a1, a2, ..., a...). n The maximum and minimum values ​​in the range are taken as the average deviation a = (a1 + a2 + ... + a) / ( ... n ) / 2 is used as the trimming amount to correct the clamping surfaces of the mounting plates at both ends, which are the machining reference surfaces and correspond to the side with thicker blade wall, to obtain the machining reference plane.

5. The method for machining the blade of an aero-engine fan after welding deformation of the hollow support plate according to claim 1, characterized in that: In step S4, regarding the wall thickness deviation values ​​of each blade measurement section, when the differences in the wall thickness results of each measurement section are large, the intermediate measurement sections other than the first and last sections are ignored, and only the first and last measurement sections are used as references, with a = (C 大1 -C 小1 ) / 2 is used as the adjustment amount to correct the clamping surface on the mounting plate closest to the first measurement section, corresponding to the side with the thicker blade wall. Take a = (C 大n -C 小n The amount of 1 / 2 is used to correct the clamping surface on the mounting plate closest to the tail measurement section, corresponding to the side with the thicker blade wall.

6. The method for machining the blade of an aero-engine fan after welding deformation of the hollow support plate according to claim 1, characterized in that: In S1, the positioning accuracy of the self-centering vise is 0.01 mm.

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