Modeling And Sensitivity Analysis Of Machine Tool Geometric Error

Manufacturing industry is the core sector of the national economy, while the machine tool is one of the important equipments to to achieve modernization of manufacturing technology, whose quality and performance can reflect a country’s industrial technology and high-end CNC machine tools is an important indicator of overall national strength.The structure design of modern machine tool is very complex, each error unit participating in parts forming will have an impact on final machine precision. The precision is an important indicator to measure the performance of the machine, so the error modeling and analysis of machine tool is especially important. Among the various sources of error forming machining errors, the proportion of geometric errors reaches 25%, which is a very important source of error. Therefore, inducting and analyzing modeling process of geometry error of machine tool and establishing the appropriate model is significant for analyzing geometry errors of machine tool and improving the machining accuracy.Taking multi-body system theory as the theoretical basis combined homogeneous coordinate transformation method in this paper, a general process of geometry error modeling of machine tool was summed up. We established theerror model of machine tool and analyzed how error of machine tool components affected manufacturing error by Matlab programming so that the generalization and visualization of error analysis machine tool were realized.The research work was depicted as follows:(1)Background and significance of research were clearly elaborated in this article. The research condition of error modeling of machine tool at home and abroad was analyzed and two methods that could reduce processing errors were introduced.(2)Basic theory of machine tool error modeling,theory of multi-body system, was introduced. The topological structure of machine tool could be obtained after reasonable simplification and refinement. The positional relationship of adjacent parts could be described with low body array and the sub-coordinate system was established on them. Kinematic model of machine tool could be established through matrix operation. So the movement relationship of machine tool became clear which offered theoretical basis for subsequent study of machine geometry error modeling.(3)The ISO method for determining the coordinate axes of machine tool was introduced and machine tools were classified according to machine tool structure. Modeling process of machine tool geometry error was analyzed and the one with wide applicability and wide range of application was summed up.Taking a four-axis and five-axis machine tools as examples, their modeling process were listed to lay a solid theoretical foundation for the subsequentsoftware writing of error modeling.(4)Software for three-axis machine tool error modeling was programmed with Matlab which could reserved interface program to prepare for further complement and improvement of modeling software. Error sensitivity and error function rule were analyzed taking 5T5.2 CNC lathe as example, which offered theoretical guidance for error compensation and tolerance design. By measuring machine actual processing and machining error, comparing with software analysis results, the theory of multi-body system and correctness and practicality of software writing were verified well.