CN-116295196-B - Automatic measurement method for twisted and deformed blade

CN116295196BCN 116295196 BCN116295196 BCN 116295196BCN-116295196-B

Abstract

The invention relates to the technical field of blade measurement, and discloses an automatic measurement method of a twisted and deformed blade, which aims to solve the problems of high labor cost, large measurement error, low measurement efficiency and scratch generation in the prior art, and mainly comprises the steps of positioning and clamping a blade to be measured on a corresponding clamp; the method comprises the steps of obtaining theoretical coordinate values of a plurality of theoretical measuring points in the vector direction of a blade to be measured, establishing a coordinate system based on a six-point iteration method, detecting the plurality of measuring points on each section of the blade to be measured by using a three-coordinate measuring machine, carrying out best fit calculation according to corresponding real measuring points and theoretical contours for each section, detecting the blade to be measured according to the actual measuring points corresponding to the theoretical measuring points in the coordinate system after best fit of each section to obtain actual measurement coordinate values, and determining the size of the blade to be measured according to the actual measurement coordinate values. The invention realizes rapid traceless automatic measurement, reduces labor cost and improves the reliability of size measurement, and is particularly suitable for aero-engine blades.

Inventors

ZHANG YOU
LIU ZHIMING
ZHOU QUN
HU YONGJUN
LUO KUILIN
REN DENGYI
ZHANG YUE
HUANG TING
YANG XUEYING

Assignees

国营川西机器厂

Dates

Publication Date: 20260505
Application Date: 20230117

Claims (8)

1. An automatic measurement method of a twisted blade, the method comprising: Step 1, placing a blade to be tested on a corresponding clamp for positioning and clamping; Step 2, acquiring a CAD model of the blade to be tested, and acquiring theoretical coordinate values of a plurality of theoretical measuring points in the vector direction of the blade to be tested according to the CAD model; The plurality of theoretical measuring points of the blade to be measured in the vector direction comprise a first measuring point and a second measuring point which correspond to the wall thickness of the front edge, a third measuring point and a fourth measuring point which correspond to the maximum wall thickness, a fifth measuring point and a sixth measuring point which correspond to the wall thickness of the rear edge, and a seventh measuring point and an eighth measuring point which correspond to the chord length; Step 3, detecting at least six measuring points of the blade to be detected by using a three-coordinate measuring machine or a comparator, and establishing a coordinate system based on a six-point iteration method; Step 4, detecting a plurality of measuring points on each section of the blade to be detected by using a three-coordinate measuring machine or a comparator to obtain real measuring points of each section, and carrying out best fit calculation according to the corresponding real measuring points and theoretical contours for each section to obtain a coordinate system after best fit of each section; Step 5, determining the position of an actual measuring point corresponding to each theoretical measuring point under a coordinate system after the best fitting of each cross section, detecting the blade to be detected according to the position of the actual measuring point, obtaining the actual measuring coordinate value of each actual measuring point, and determining the size of the blade to be detected according to the actual measuring coordinate value; The determining the position of the actual measuring point corresponding to each theoretical measuring point specifically comprises the following steps: For the third measuring point, the fourth measuring point, the seventh measuring point and the eighth measuring point, determining the positions of the corresponding actual measuring points in the best-fit measured profile according to the vector directions; For the first measuring point, the second measuring point, the fifth measuring point and the sixth measuring point, the position of the corresponding actual measuring point is determined in the best-fit actual measuring profile according to the distance between the first measuring point and the seventh measuring point and the offset of the seventh measuring point in the chord line direction, or the position of the corresponding actual measuring point is determined in the best-fit actual measuring profile according to the distance between the first measuring point and the eighth measuring point and the offset of the eighth measuring point in the chord line direction.
2. The method for automatically measuring a twisted blade according to claim 1, wherein in the step 3, at least six measuring points of the blade to be measured are thirteen, and the measuring points comprise three measuring points on a blade basin, three measuring points on a blade back, three measuring points on an air inlet side, three measuring points on an air outlet side and one measuring point on a blade top.
3. The method for automatically measuring a twisted blade according to claim 1, wherein in the step 4, the number of the plurality of measuring points on each section of the blade to be measured is six, and the plurality of measuring points includes two measuring points on a blade basin, two measuring points on a blade back, one measuring point on an air inlet side and one measuring point on an air outlet side.
4. The method for automatically measuring a twisted blade according to claim 1, wherein in step 5, the dimension of the blade to be measured is determined according to the measured coordinate values, specifically comprising: According to the actual measurement coordinate values of the corresponding actual measurement points of the first measurement point and the second measurement point in the best-fit actual measurement profile, calculating a first distance between the actual measurement point corresponding to the first measurement point and the actual measurement point corresponding to the second measurement point, wherein the first distance is the actual front edge wall thickness of the blade to be measured; Calculating a second distance between the actual measuring point corresponding to the third measuring point and the actual measuring point corresponding to the fourth measuring point according to the actual measuring coordinate values of the actual measuring point corresponding to the third measuring point and the actual measuring point corresponding to the fourth measuring point in the best-fit actual measuring profile, wherein the second distance is the actual maximum wall thickness of the blade to be measured; According to the actual measurement coordinate values of the actual measurement points corresponding to the fifth measurement point and the sixth measurement point in the best-fit actual measurement profile, calculating a third distance between the actual measurement point corresponding to the fifth measurement point and the actual measurement point corresponding to the sixth measurement point, wherein the third distance is the actual trailing edge wall thickness of the blade to be measured; According to the actual measurement coordinate values of the actual measurement points corresponding to the seventh measurement point and the eighth measurement point in the best-fit actual measurement profile, calculating a fourth distance between the actual measurement point corresponding to the seventh measurement point and the actual measurement point corresponding to the eighth measurement point, wherein the fourth distance is the actual chord length of the blade to be measured.
5. The method for automatically measuring a twisted blade according to claim 4, further comprising: And obtaining the standard front edge wall thickness, the standard maximum wall thickness, the standard rear edge wall thickness and the standard chord length of the blade to be measured through three-coordinate scanning, comparing the measured actual front edge wall thickness, the measured actual maximum wall thickness, the measured actual rear edge wall thickness and the measured actual chord length with the standard front edge wall thickness, the standard maximum wall thickness, the measured standard rear edge wall thickness and the measured standard chord length respectively, judging whether the measurement precision meets the condition, and if not, correcting the position of the theoretical measuring point until the measurement precision meets the condition.
6. The method for automatically measuring a twisted blade according to claim 4, further comprising generating a corresponding measurement report according to the lot number, the serial number, and the measurement data of the blade to be measured.
7. The method of automatically measuring a twisted blade of claim 6, further comprising: and extracting measurement data in the measurement report, judging whether the blade to be measured is qualified or not according to the measurement data, and uploading the measurement report and a judgment result to an enterprise data management system.
8. The automatic measurement method of a twisted blade according to any one of claims 1 to 7, wherein the three-coordinate measuring machine is a contact three-coordinate measuring machine or a non-contact three-coordinate measuring machine.

Description

Automatic measurement method for twisted and deformed blade Technical Field The invention relates to the technical field of blade measurement, in particular to an automatic measurement method of a twisted and deformed blade. Background After the aeroengine fan blade or turbine blade is polished and repaired, the wall thickness and the chord length of the weak position of the blade are required to be measured so as to ensure the strength of the blade. The current method for detecting the size of the repaired aero-engine blade at least has the following defects: (1) After polishing and repairing the domestic aeroengine blade, the wall thickness and chord length size detection mainly uses special wall thickness detection tools, clamping plates, calipers and other manual detection means, and has the problems of high labor cost, large measurement error and the like. (2) The wall thickness and chord length dimensions of the repaired blade are smaller than those of the drawing, the consistency of each blade is poor, the problem of torsion and tenon positioning reference abrasion of the blade profile after service is solved, a traditional blade profile scanning mode is used, and especially automatic scanning of fan blades with the radius of the front edge and the rear edge R smaller than 0.3mm is extremely unstable, and automatic measurement of the deformed blade with the complicated twisted profile is difficult to realize. (3) The fan rotor blade with the boss has incomplete profile sections on the section where the boss is located, the virtual section of the blade root or the blade tip, and the fan rotor blade is a dead angle area for tool or traditional three-coordinate scanning measurement. (4) Whether in a traditional manual tool measurement mode or a three-coordinate scanning measurement mode, measurement scratches are formed on the surface of the blade body, the processing difficulty of the blade after measurement is increased, and the quality hidden trouble exists. Disclosure of Invention The invention aims to provide an automatic measurement method of a twisted blade so as to realize rapid traceless automatic measurement of the size of a complicated twisted blade, reduce labor cost and improve the reliability of size measurement. The technical scheme adopted by the invention for solving the technical problems is as follows: an automatic measurement method of a twisted blade, the method comprising: Step 1, placing a blade to be tested on a corresponding clamp for positioning and clamping; Step 2, acquiring a CAD model of the blade to be tested, and acquiring theoretical coordinate values of a plurality of theoretical measuring points in the vector direction of the blade to be tested according to the CAD model; Step 3, detecting at least six measuring points of the blade to be detected by using a three-coordinate measuring machine or a comparator, and establishing a coordinate system based on a six-point iteration method; Step 4, detecting a plurality of measuring points on each section of the blade to be detected by using a three-coordinate measuring machine or a comparator to obtain real measuring points of each section, and carrying out best fit calculation according to the corresponding real measuring points and theoretical contours for each section to obtain a coordinate system after best fit of each section; and 5, determining the positions of the actual measuring points corresponding to the theoretical measuring points under the coordinate system of the best fit of each cross section, detecting the blade to be detected according to the positions of the actual measuring points, obtaining the actual measuring coordinate values of each actual measuring point, and determining the size of the blade to be detected according to the actual measuring coordinate values. Further, in the step 2, the plurality of theoretical measuring points of the blade to be measured in the vector direction comprise a first measuring point and a second measuring point corresponding to the wall thickness of the front edge, a third measuring point and a fourth measuring point corresponding to the maximum wall thickness, a fifth measuring point and a sixth measuring point corresponding to the wall thickness of the rear edge, and a seventh measuring point and an eighth measuring point corresponding to the chord length. Further, in the step 3, the at least six measuring points of the blade to be measured are thirteen, wherein the at least six measuring points comprise three measuring points on a blade basin, three measuring points on a blade back, three measuring points on an air inlet side, three measuring points on an air outlet side and one measuring point on a blade top. Further, in step 4, the number of the plurality of measuring points on each section of the blade to be measured is six, including two measuring points on the blade basin, two measuring points on the blade back, one measuring point on the air inlet side and one me