| In this paper, the effect on machining accuracy of CNC machine cutting forceerror and cutting force due to geometric errors was studied. First of all，a survey andanalysis about calibration technology of NC machine error were made. Then based onthe theory of multi-body system of the machine geometric error and cutting forceerrors comprehensive error modeling was made. Through experiments and simulationwe analyze the reasons for circular interpolation motion when the machine radial errorgenerated. The main contents include the following aspects:1. Based on the theory of multi-body system for integrated error modeling ofthree axis NC machine tools. Expounds the basic theory of multi-body systemkinematics; take Cincinnati Arrow750type NC machine tool as an example, the maincomponents of machine tools (lathe bed, column, spindle, cutting tool, X, Y, Z toskateboard, workbench) geometric error and error mathematics model is set up.Comprehensive error vertical boring and milling machining center with the derivationof mathematical model in this paper has strong universality and can be transplanted,and can be easily transplanted to other types of CNC machine error in the model.2. Geometric error two-axis CNC machine state was studied. In this paper,Cincinnati Arrow750CNC machining center served as research object, and we use theorthogonal plane grating to measure the circular trajectory of NC machine tools withdifferent feed speed, under the condition of different radiuses. According to ACCOMsoftware we view all kinds of sports under the condition of circular trajectory of theradial error, through the analysis of experimental data contrast, summing up thecircular interpolation motion with the feed rate and feed radius radial error between thechanges of the trajectory. Then find the machine for circular interpolation motion whenthe radial error with the function relationship between rate and feed radius throughtheoretical analysis. The theoretical derivation was the same as experimental resultsconclusion. Finally, analyze the impact of the servo control system on the circular motion of the radial error of CNC machine tools3. Research on dynamic characteristics of machine tool and analysis the influenceof cutting force on the machining accuracy of NC machine tools. Study the dynamiccharacteristic of the finite element model of Cincinnati Arrow750type CNCmachining center by using3D drawing software CATIA and finite element analysissoftware ABAQUS, studying the stability of the machine tool under the vibration force;and dynamics analysis was made to find how the deformation of machining center isinfluenced by cutting force. Draw X direction in the manufacturing process of machinetool for cutting force sensitive direction, and the second is the Y direction, whichprovides a direction for cutting force error compensation in the future.4. Research when tools did circular interpolation motions the influence ofgeometric error on circular radial error. Built simulation system in the Matlab/simulink.Simulation was carried out on the machine tool geometric error. By adding singlegeometric errors in the simulation system we simulated the circular interpolationmotion of the machine, then look at the next round of monomial error trajectory ofcontour shape. Through the analysis of circular trajectory simulation graphics andcircular trajectory experiment graphics, find every single error’s influence on thetheory of circular interpolation motion. Simulation system can not only simulate theinfluence of geometric error on circular trajectory when the machine makes a standardcircular movement, but also the influence of the geometric error on the trajectorymotion when it makes irregular geometric, which laid a solid foundation for themachine tool error compensation later. |
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