Research On CMM-based Measuring System Of Blisk

As a key component of an aero engine,the blisk has become the development trend of advanced aero engines because of its characteristics of small mass and large thrust-toweight ratio.Blisks are significant precision parts for aero engines,and their manufacturing accuracy has a huge impact on the performance of the engine.It is very difficult to measure blisk because of the complex structure of the blisk and the high accuracy requirements for manufacturing and measurement.Achieving the high efficiency and high-precision measurement of the blisk plays a very important role in improving the production efficiency of the blisk.However,in the current process of blisk measurement,the key measurement technology is mainly in the hands of foreign manufacturers with quite expensive price in measurement equipment.Besides,the monopoly policy is imposed on the Chinese market.Additionally,the evaluation standards of the blisk are various by different manufacturers.In view of the above problems,a cost-effective measurement system for the blisk measurement was developed,and expanded on key issues such as error compensation,measurement point sampling distribution,trajectory planning,probe angle planning,and quality evaluation and so on.The main contents of this paper are as follows:(1).According to the measurement characteristics of the blisk,the mechanical structure of the blisk measurement system is designed,and the rotation degrees of freedom are respectively distributed to the probe head and the blisk turntable support.To transform the high-precision indexing disk into a probe head to increase the degree of freedom of the probe in the direction of the B axis.The design of the vertical turntable support can complete the indexing positioning function of the blisk,and facilitate the measurement of the blisk by the probe.To carry out finite element analysis on the turntable support to verify its rigidity.To study the error mechanism of the measurement system,design the measurement method and modeling method of each error,propose the overall error compensation model of the measurement system,and perform error compensation on the system.(2).According to the measurement requirements of the blisk,it is proposed to divide the blisk into regular parts body of blisk and irregular blisk parts for measurement.For blade measurement,in order to ensure the accuracy and efficiency of the measurement,a blade measurement point sampling method based on the chord height difference method and particle swarm algorithm and a probe position and attitude calculation method are proposed,which can be adaptively distributed according to the geometric characteristics of the blade Measuring cross section and measuring sampling point.By analyzing the requirements of the blisk and combining with the measurement characteristics of the blade,the evaluation standard of the blisk will be put forward.(3).A software system dedicated to the rapid measurement and quality analysis of the blisk was developed under the VS2010 development environment.Based on the CAD model of the blisk,the system can generate the coordinates of the self-adaptive measurement sampling points and the probe pose angle of each sampling point,plan the optimal measurement path,and realize the fast and non-interference measurement of the blisk.Finally,compared with the traditional three-coordinate measuring machine for the blisk measurement experiment,the results showed the effectiveness and accuracy of the measurement system developed in this paper.