Research On Performance Optimization Of Conductive Shaft Of Large Horizontal CNC ECM Machine Tool

The large diameter special-shaped inner spiral deep hole parts are widely used in oil drilling and production,weapons and equipment,aerospace and other fields.Electrochemical machining is widely used in the machining of large diameter special-shaped inner spiral deep hole parts,because of its advantages of no cutting stress,no tool loss,high machining efficiency.Under the processing conditions of large current,small gap and long time,the conductivity of the conductive shaft of the large horizontal CNC ECM machine tool is poor,and even the erosion of the conductive shaft body occurs.This will cause the ECM process to stop.In this paper,the conductive shaft structure of large horizontal CNC ECM machine tool is studied as follows:Firstly,the structure of conductive shaft device of horizontal NC ECM machine tool is designed.And the morphological matrix is established to realize the functions of conductivity,sealing,support and so on.Different schemes are analyzed and the best scheme is obtained.Under the same working condition,the temperature field of conductive shaft structure of conductive slip ring and carbon brush is studied.The overall structure based on carbon brush conductivity is established.The problem of poor electrical conductivity and easy ablation of the shaft body of the conductive shaft structure under conditions such as high working current and long processing time is solved.Secondly,the conductive shaft thermoelectric coupling model is established.And the temperature field distribution law of the conductive shaft structure is revealed.The influence of process parameters on the temperature rise of the conductive shaft structure is explored.The temperature mathematical model is established based on the principle of SVM and multiple linear regression.The temperature change law of the monitoring points under the different process parameters is studied.Realize the purpose of predicting monitoring point temperature under different process parameters.The results show that the influence level of working current is the highest,and the influence level of ambient temperature is the second.The structure optimization scheme of the conductive shaft is proposed to improve its heat dissipation performance and stability and reliability.Thirdly,the mechanical characteristics of the conductive shaft structure are analyzed.And under different feeding feed motions,the axial force,torsion characteristics and bending moment characteristics of the conductive shaft body and the feeding device under the action of external load are studied.Compared to the push motion of a machine tool,the pull motion causes the feed device to experience less bending moment,shear force,angle,and bending deformation at the same position.In addition,the bending moment of the feed device under pull motion gradually decreases with the increase of working time.Pull motion makes the machine tool have better stability and resistance to damage deformation,and improve the stability of ECM.Finally,the performance verification experiment of the conductive shaft structure is carried out.The designed conductive shaft structure is applied to the large horizontal CNC ECM machine tool.Determine the pull type as the movement mode of the ECM machine tool.The test shows that: under the condition of the voltage is 12.0 V and the feed speed is 5.0 mm/min,the stable and reliable processing of the stator of the all-metal petroleum screw drill is realized.The whole process requires continuous processing for 12 hours,the designed conductive shaft structure runs smoothly.The results show that the conductive shaft has good performance and meets the actual needs of ECM.