Thermal Characteristics Analysis On The Feed System Of The TX1600g CNC Boring And Milling Machining Center

With the rapid development of manufacturing industry to high speed and high precision,it puts forward higher requirements to the machining accuracy and reliability.Therefore,how to reduce the thermal deformation and improve the machining accuracy is the difficult and important issue in the design of the machine tool.Guide rail and ball screw are the key component to the feed system of CNC machining center.The guide rail plays a role in supporting and guiding,and the ball screw plays a role in precision transmission and positioning,their thermal deformation will seriously affect the machining precision.This paper begins with the introduction of domestic and international situation and development trend of thermal error compensation technology,takes the feed system of the TX1600G boring and milling machining center as the object of this research,analyzes its structure characteristics and the main internal heating source,to highlight the significance of thermal error compensation technology by comparing with error avoid method.It discusses the thermal boundary conditions of the guide rail and ball screw based on the heat conduction and the finite element theory for finite element analysis.With the help of the Solidworks software to establish a simplified three-dimensional entity model of the feed system and through the ANSYS finite element analysis software,using the method of moving heat load to simulate the changes of temperature field,and determine the time when reaches to the steady state,and then adopt thermal structure coupling method to simulate the variation of thermal deformation.Investigating the effect of feed rate,convection coefficient,coolant flow rate and screw hollow on the temperature field and thermal deformation of the feed system,so that we can sum up the effective measure to reduce thermal deformation.A experimental scheme is proposed for temperature and thermal error measurement to understand the characteristics and relationship of temperature field and thermal deformation in a certain condition.Based on the simulation results,this research lays out six measuring points at first,and using the fuzzy clustering method to determine the four groups of temperature measuring point,by using F statistics analysis to determine the optimal threshold so that determine the optimal grouping scheme,calculate the correlation of temperature and thermal error to selection of the final key used in thermal error modeling,by this way,the temperature measuring point reduced from six to three.Discuss the modeling accuracy by using regression and GA-BP neural network and the results shows that the GA-BP neural network can better predict the relationship between the temperature and the thermal error.Finally based on the Matlab-GUI developing a simulation system for optimization the key point and establishing the error compensation model and via an example to verify the feasibility of it.Through this research illustrates that the thermal error compensation techniques plays a vital role in improving the processing and positioning precision of the feed system,therefore,it is significant in engineering.