Research On Measuring Method Of Volumetric Error Of Machine Tool Based On Combined Double Ball Bar

The machining accuracy of CNC machine tool directly determines the quality of the machined parts.The volumetric error is one of the key factors affecting the machining accuracy of CNC machine tool.Therefore,accurate measurement of the volumetric error is the premise of improving the machining accuracy of CNC machine tool.Using the double ball bar measurement method to directly detect the volumetric error of machine tool usually requires multiple measurements in different measurement planes,which has the limitations of low measurement efficiency and limited detection and analysis accuracy.therefore,a new measurement method based on Combined Double Ball Bar(C-DBB)is proposed in this paper.This method can obtain the volumetric error of machine tool circular path in a single measurement experiment,which is of great significance for the high-precision and high-efficiency detection of the volumetric error.Besides,the appropriate machine tool processing area can be select according to the individual processing requirements(processing accuracy,processing range,etc.)of the components,to improve the machining accuracy of components and give full play to the performance of the machine tool,which has important guiding significance for actual machining.This paper focuses on the feasibility and effectiveness of the C-DBB method for machine tool volumetric error measurement by combining theoretical analysis and experimental research.The main research work is summarized as follows:Firstly,the volumetric error of machine tool and its measurement methods are described comprehensively,the limitations of existing methods in the measurement and analysis the volumetric error of machine tool are summarized and analyzed,and the optimal measurement method for volumetric error is discussed.It provides a basis for the next study of measurement of volumetric error.Secondly,the C-DBB method for measuring the volumetric error of machine tool is proposed.The error measurement principle of the C-DBB method is introduced,the measurement coordinate system and the measurement model based on the C-DBB method is established,the error measurement accuracy of the C-DBB method is analyzed,the key problems in the application of the C-DBB method is discussed,which lays the foundation for the next design of the C-DBB device.Then,based on the measurement principle of the C-DBB method,the mechanical structure design scheme of the C-DBB device is proposed.The lever principle is used to realize that two double-ball-bars can measure the errors in different directions at the same position at the same time.the structural parameters of the C-DBB device are analyzed,the allowable error range is determined,and the detailed design is completed,which lays the foundation for processing and manufacturing the C-DBB device.Finally,the prototype of the C-DBB device is constructed,and the experimental research is carried out on the CNC vertical milling machine to verify the feasibility and effectiveness of the C-DBB method for the volumetric error of machine tool.