Research On Geometry Error Compensation For Mutil-Function CNC Milling Machine

The machining accuracy is one of the most important performance indexes for machine tools. This topic details the geometric accuracy problems of the four-axis CNC milling machine based on the error analysis theory of kinematics for multi-body system (MBS) systemically and lays the strong emphases on the error modeling ,the studying of the error identifying, machining accuracy predicting and software error compensating and so on. With the error model of the multi-axis CNC machine tools, their error transferability rules from the machine body to the machined work pieces are opened out and their errors compensated based on software is also opened to increase their machining accuracy.The MBS kinematics theories are applied to study the accuracy of error kinematics develops a new usage field. Though these researches began to be think much till the last few years, they have already displayed their mighty vitality. The kernels of MBS theories are that the number arrays of low-order body are used to describe the topological structures and the characteristic matrixes are employed to represent the relative positions and gestures between any two bodies in MBS. This topic has carries many part on the theory of MBS. After that, a kind of universal precision model for four multi-axis CNC machine tool according to the proposed MBS kinematics theory are raised and the topic has given the concrete expressions of volumetric error model for a four-axis machine tool.According to the established precision model of machine tools, the examination of their error parameters have been done. There are many kinds of error parameters in a machine tool to influence its machining accuracy. For example, geometric errors, heat deformation errors and force deformation errors etc. And there are also many kinds of the examination to measure the error parameters .After introducing some measures, this topic has introduced nine-line method and used the light-sensor and million meter to measure and evaluate 21 geometric errors for a four-movement-axis system milling machine. In order to identify 6-freedom errors of turning-axis, this paper has detailed the identification mechanism of these errors according to radial errors, axis errors and turning errors. Based on these researches, the problems of the error examination of machine tools in the application process of MBS theories are resolved perfectly. After error modeling and error examination completed, machining accuracy predicting and error compensating can been carried through with that. We can get the detail dater by the two dimensions calculation of volumetric point and get justly error dater of those points on the flat surface and inclined planes. This paper has put a great emphasis on the deep study of software error compensation based on direct calculation methods modifying ideal numerical control instructions. At last, we get the better machining accuracy without making the alternation of the component part of the four-axis CNC machine tool and that is our ultimate aim.