Process Perception Method Of Thermal Error In NC Machining Process

Process perception is an important part of the intelligent manufacturing line.Through online perception of the state change information in the NC machining process,error compensation and control can effectively improve the dimensional accuracy of the processed parts.The thermal error of machine tool is one of the main factors that affect the machining accuracy of parts.In the process of machine tool machining,the temperature rise of the feed system causes the deformation of the structural parts,which results in the relative error between the forming point of the tool and the point to be machined,and the machining accuracy of the workpiece is reduced or discarded.How to detect the temperature rise of machine tool structure,predict the position error between tool and workpiece,and implement online error compensation is the frontier technology of intelligent manufacturing.In this paper,the process sensing technology of CNC machine tools is studied from the aspects of finite element simulation analysis,machine tool thermal error modeling and process sensing system development.A method for error perception of machining process information of CNC machine tools is proposed.The method establishes the thermal error mapping model of the machine tool based on multi-body system theory,and develops and designs the NC code information extraction and recognition program.On this basis,the process-aware human-computer interaction interface is designed to realize the error perception of NC machining information.Taking horizontal machining center as the research object,heat generation and heat dissipation model of the machine tool was established.According to different working conditions,the finite element software was used to simulate the temperature field and deformation field of the main structural parts of the CNC machine tool.The deformation value of the guide rail was extracted,and the deformation law of the guide rail on the structural part was studied.Base on the results of thermal deformation simulation analysis,a mapping model of rail deformation to single-axis thermal error is established,which provides a basis for thermal error modeling of CNC machine tools.The multi-body system theory is used to obtain the position transformation matrix between the various parts of the machine tool.The end thermal error mapping model of the CNC machine tool is established.The spatial distribution law of the machine end error is studied and analyzed.It provides a model basis for process sensing of CNC machine tools.The thermal characteristics of CNC machine tools were experimentally studied by multi-beam laser interferometer and temperature information acquisition system.Using C#,Lab VIEW and MATLAB as development tools,the G code information reading program and temperature information acquisition program of CNC machine tools were developed and designed.Based on this,the process-aware human-computer interaction interface was designed and developed based on MATLAB GUI.The research results of this paper provide a new method for temperature control,machining accuracy compensation and process optimization of CNC machine tools,which provides a more accurate theoretical basis and a more comprehensive evaluation method for thermal balance control and thermal error compensation of CNC machine tools.It is of great significance for guiding the processing and precision control of batch parts processing.