Optimum Design On Measuring Plate And X-beam Of Coordinate Measuring Machine

Coordinate Measuring Machine(CMM)is a modern,multi-functional precise measuring instrument,and the large-scale horizontal arm CMM has a wide range of applications in the aerospace industry,automotive industry and manufacturing industry,but there is a disadvantage of measuring accuracy and manufacturing costs in the localization process.In this paper,through the analysis and optimization design of some important structural parts in the existing horizontal arm CMM,to get improvements on the load capacity and measurement precision.The main work includes the following aspects:Outlining the functions and characteristics of the measuring plate of horizontal arm CMM.Analyzing and comparing the different feet layout structure of the measuring plate by finite element method,finding the best feet layout through the comprehensive comparison of various indexes.Then,introducing the common ribs layout of casting measuring plate,using the topology optimization method to optimize the ribs layout and rebuild the 3D model.Through the theoretical analysis,the weight is reduced and the load capacity is improved after the topology optimization.After that,introducing the functions and characteristics of the X-Beam of horizontal arm CMM,analyzing the deformation of the X-Beam when the temperature is changed.Then,the method of using multiple flexible supports to reduce the about-mentioned deformation is proposed,after the theoretical proof of the method is valid,the key dimensions of the flexible support are subjected to the multi-index orthogonal test,and the best structure is obtained.Finally,the theoretical analysis of the thermal deformation is carried out for the method using multiple flexible supports.Lastly,experiments are made to verify the new structure measuring plate and the X-Beam.In the experiment of the measuring plate,the flatness error is investigated in the stages after milling and after adjusting.The experiment of the X-Beam mainly includes three items,the accuracy test after the installation of the X-Beam,the accuracy test after the installation of the CMM machine and the test when there is a temperature difference inside the X-Beam.The experimental results show that the new structure of the measuring plate and X-Beam can meet the design requirements.