Error Analysis And Research On Compensation For Large Spiral Bevel Gear NC Milling

The machining precision of NC machine tool is one of the most important performance indexes. We do the comprehensively and deeply analysis and research with the CNC machine tool geometric error and thermal error which based on the theory of multi body system. We focus on the error modeling of CNC machine tools, measurement error, error identification, error compensation and other areas of research. We explain the error transfer rules trough the error modeling of CNC machine in order to make the error compensation is more simply.Based on the theory of multi-body system error modeling method which is developed in recent years, its essence is the low order body array describes the topological structure of multi body system which describe with characteristic matrix description of multi body system of relative position and attitude. In this paper we analyze the theory of multi body system and use it describe and analyze the detail, and establish a large spiral bevel gear NC machine tool error analysis model, and give its spatial error model and express it.This paper introduces 9 line identification method, and uses the closed type grating sensor and a mechanical dial indicator to test the large spiral bevel gear NC machine tool three translational axis of the 21 geometric errors. In order to test its rotary shaft 6 errors, elaborating the radial, axial and rotational error identification mechanism, so as to solve the multi body system theory in the application of geometrical error of machine tool testing problem. We analyze the thermal error variation and thermal error detection with the five point measurement method, and make error compensation. In order to find the best five points, this paper uses regression analysis method of error of NC machine tool to analysis each part to find the required five points.Based on discrete points error value of two-dimensional interpolation data to achieve the sealing treatment, getting the plane and inclining the plane processing dense point error calculation, and make NC software compensation in the large spiral bevel gear NC machine tool with the realization of the direct calculation method of correction theory instruction, thus have the more ideal processing precision without altering the original machine manufacturing precision.