Thermal Characterisation And Modelling Of Thermal Errors In A Double Oscillating Angle CNC Milling Head

As the main carrier of the machine tool spindle,the performance of the milling head has a direct impact on the surface quality and accuracy of the workpiece processed by the machine tool.With the increase in the precision of machine tool spindles,the internal components tend to be integrated,which inevitably generate a lot of heat during the working process.The heat will lead to thermal deformation of the front end of the spindle and deviations in positioning.Machining accuracy decreases and even leads to mechanical failure.The future of machine tool milling head machining systems will face challenges such as higher mechanical and thermal loads,and there is an urgent need to address the technical challenges of temperature rise due to high speed and structural integration.Thermal error compensation is an effective method.Therefore,it is necessary to conduct thermal characterization and thermal error modeling research.In this paper,the internal thermal characteristics of a double-oscillating angle CNC milling head are analyzed as a research object.The finite element method is used to simulate and analyze the milling head.The thermal deformation experimental platform to collect data is built.The thermal error model is established.The research results can provide the theoretical basis and technical support for the thermal error compensation and optimal design of the double-oscillating CNC milling head,which is expected to be effectively applied and promoted in the actual machining.Firstly,the thermal characteristics of the milling head are analyzed based on the basic structure of the head.The material property parameters provided by the company are utilized.The heat generated from the main heat sources is calculated.This includes calculations of the heat generated by the friction of the bearings and the heat generated during the operation of the motor.The main heat transfer methods inside the milling head are explored.Heat dissipation coefficients are calculated for different forms of exchange.The results can provide the basis for simulation analysis.Secondly,the milling head model is established.The finite element analysis method is utilized.Steady-state and transient simulations of the double swing angle milling head are performed based on the boundary load parameters.The temperature field distribution and thermal deformation of the milling head are obtained.Simulation results are analyzed.The heat change pattern inside the milling head is explored.The temperature-sensitive zone of the milling head is determined.The temperature measurement points of the milling head are set.Again,the principle of thermal deformation of the milling head spindle is analyzed.The effect of heat deformation principle on machining accuracy is discussed.The temperature sensor is set according to the temperature sensitive area obtained from the simulation analysis.Displacement sensor is set at the front of the spindle.The thermal deformation experiment platform is built.Experimental conditions and environmental conditions are designed.The temperature data and displacement data of the milling head are collected and analyzed.Simulation results and experiments are compared.The variation law of airframe temperature and displacement with time is explored.Finally,the KHM and GRA methods are applied to optimize the temperature measurement points of the milling head.The influence of the correlation between temperature variables on the accuracy and robustness of the prediction model is also reduced.The LSTM-CNN thermal error model of the milling head is developed.The prediction accuracy of the proposed model is verified by comparing it with the conventional thermal error model.Surface fit the temperature and displacement data by the data obtained from the experiment.The robustness of the model is verified.