| The reason of thermal error of spindle was analysed,and the error elements of spindle are classified and generalised.The thermal characteristics of CK6430 turning machine were discussed.The error compensation is executed through the communication between CNC system and external device.The main topics of the essay are as below:(1).The synthetic radial error and axial error are introduced after the analysis and classification of all the seven error elements.The measurement method for spindle error by using five displacement sensors is introduced.The calculation of thermal load and convection coefficient of spindle were implemented based on heat transfer theory.The FEA simulation was implemented to verify spindle error caused by non-uniform deformation of spindle housing and bearing.(2).The hysteresis effect between spindle error and temperature data of certain measurement points on spindle housing is analysed by using FEA simulation.The measurement points are classified into two types,hysteresis points and leading points,based on the simulation result.A mathematical model,named Multivariate Synchronous Model,is proposed to anticipate and fit spindle thermal error,by postponing the temperature data of all the leading points artificially to match the meanwhile error data.(3).A thermal error compensation system is introduced,including its architecture and communication with CNC system.The displacement sensors used in the system are introduced.The development of MFC program software for error measurement in Windows environment by using C++ is introduced.(4).An experiment is implemented to verify the existence of the hysteresis effect.The correlation between temperature data and spindle thermal error data is increased after the lag operation.(5).Compensation experiment is executed to verify the fitting precision of the multivariate synchronous model.The result shows that the spindle thermal error was limited with 5?m,over 70% of which was compensated. |
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