Modeling And Simulation Of The Feed Drive System Dynamic Stiffness For CNC Engraving And Milling Machine

In CNC engraving and milling machine, Feed drive system is a link betweendigital-controlled device and machine bed．It is an important part of digital-controlledsystems．When feed drive system is designed，it must satisfy the designing requirements，then it can insure the positioning precision and dynamical state characters of feed servosystem．Thus，it can insure machining precision of a machining tool．Modern CNCengraving and milling machine trends toward to high speed．high efficiency and highprecision．The designing requirement for machine tool feed drive system has been moreand more higher．Obviously，positioning precision of the CNC engraving and millingmachine is one of the important guideline to judge the performance．The influence factorof the positioning precision are multiform，dynamic rigidity of the feed drive system is theuppermost. So whether it can achieve the best comprehensive effect，will has veryimportant influence to the parts processing quality.After studying modeling and simulation of the feed drive system dynamic stiffnessfor CNC engraving and milling machine，according to the feed drive system structure ofthe relationship between each component and the inner mechanism of the obtained thetransfer function of each link, and then integrated to feed drive system of the transferfunction. Finally established the CNC engraving and milling machine acomprehensivemathematical model of all-in-one feed drive system including mechanical-drivencomponents，drive electric motor and executive components in which gap and frictionnon-linear factor was considered．Respectively at the same time the system servo stiffness,torsional rigidity and axial rigidity were analyzed, and puts forward the measures toimprove the dynamic rigidity of the feed drive system and method.Based on MATLAB7.0Simulink module to simulation analysis CNC engraving andmilling machine feed drive system model, using a fixed step algorithm in the explicitfairly RK algorithm, that is the runge-kutta algorithm, simulation curve reflects theperformance of the system are obtained.On this basis, discussed the influence of dynamic characteristics on the wholesystem of feed drive system parameters,then gives the reasonable value of feed drivesystem in CNC engraving and milling machine for study. The conclusion will betheoretical suggestion applied to engineering design．Finally put forward the non-linearfactors in the analysis system dynamic stiffness needs to be taken into consideration andvery necessary.