Research On The Control Technology Of Thermal Deformation Of Heavy CNC Hydrostatic Turntable

Hydrostatic turntable is a critical component of CNC vertical lathe,its performance determines the processing ability and machining precision of the CNC vertical lathe.In general,the hydrostatic oil film is less friction than the solid bearing,but the temperature of the lubricant film rise along with the size of the turntable increased,processing range growth,load-demand increased,which cause thermal deformation of turntable,that seriously affects its processing precision.Based on this,the key to solve this problems is to study the thermal characteristics of the lubricant film and control the thermal deformation of the turntable and lubricant film’s temperature increase.This thesis takes the SKCX100 intelligent temperature control system experimental platform as the research object,which comes from a machinery plant factory,studying on the temperature rise mechanism of the hydrostatic oil film under different working condition,building the thermal error model of the turntable,and,the thermal error compensation software is developed and the temperature control system is built to reduce the thermal deformation of the turntable.In this paper,the main research contents include the following aspects:Firstly,the thermal characteristics of the oil film of the hydrostatic turntable under different working conditions are simulated and analyzed.FLUENT is used to simulate and analyze the bearing capacity and heating characteristics of the hydrostatic oil film under the condition of loading and partial load.At the same time,ANSYS WORKBENCH is used to analyze the thermal deformation of the turntable,which providing theoretical basis for the establishment of the thermal error model for the turntable.Secondly,study on the law of generates heat of the turntable under different working conditions by experiment.LABVIEW and Data Acquisition Board and temperature sensors and displacement sensors are used to collect and store turntable temperature and thermal deformation data at different speeds,loading and loading modes.Not only validating the correctness of the simulation method,but also explore the relationship between the temperature rise and the thermal deformation of the turntable,and provide dates for the thermal error model of the turntable.Thirdly,the thermal deformation prediction model of the hydrostatic turntable is set up,and the thermal error compensation software for the turntable is designed.By combining the relevant mathematical theory with the experimental data,the key temperature rise points in the working process of the turntable are selected.The temperature of key points is brought into the support vector machine model optimized by intelligent algorithm to train the error model.The thermal error compensation software that can be applied to SIEMENS 840 D CNC system is developed.The trained support vector machine model is embedded in the compensation software,which can finish the calculation of thermal error online.Compensation software can interact with CNC systems in the way of OPC.Finally,build the temperature control system of the hydrostatic turntable.Select PLC as the controller,the air conditioner and the oil cooler as the actuating device,combination fuzzy control algorithm build turntable temperature control system.It is used to reduce the temperature rise of the environment and the temperature rise of the lubricant film in the working process,thus reducing the thermal deformation and improving the thermal deformation of the turntable.