Analysis Of Influencing Factors And Sliding Mode Control Of Tension For Reciprocating Single Diamond Wire Saw Cutting Machine

The SiC mono-crystal has become the ideal material for the 3rd-generation semiconductors because of its well heat transmission,high disruptive potential,and other outstanding characteristics.However,due to its hardness and crispness,the machine of SiC ingot is very difficult when it is sliced by wire saw.Research finds that wire saw tension is an important factor to impact the vibration of wire saw.If wire saw tension can be held constant,the vibration of wire saw will be reduced and the surface quality of SiC will be improved.Furthermore,it lays a good foundation of subsequent SiC machining.So this paper analyzes main factors that influence wire saw tension by establishing kinetic model of tension of wire-feeding system which is a part of the single reciprocating diamond wire cutting machine,designs tension controller based on sliding mode control algorithm and experiments tension control.The main contents in this paper include:Based on mechanical structure,kinematics characteristics of the single reciprocating diamond wire cutting machine and tensile strain perspective of wire,this study has modeled tension of wire-feeding system.By simulation and experiment,the tension mutation is obtained when wire saw starts and stops,and changes moving direction.Also,the tension values of wire in these conditions are considerably larger than preset value.The influence of drum or guide wheel radial run-out,frictional force between wire and guide wheel,asymmetry of wire-feeding system,input torque of motor,spans of wheels and inertia of the drum and guide wheel on the tension is obtained,which shows that the drum or guide wheel radial run-out has the most impact to tension and the asymmetry of wire-feeding system has a minimal impact on tension.The transfer function of tension control system is established.The sliding mode controller directly based on equation of state and that on dynamic surface are designed.The stability,fast response of tension control system and the effectiveness of sliding mode controller to tension control are verified by simulation and experiment.In conclusion,software and hardware debugging on wire tension control system is completed and experiment of tension control in no load condition and simulated cutting process is fulfilled in this paper.The experimental results show that the sliding mode controller has better robustness and significant control effects on wire tension,and sliding mode controller directly based on equation of state is more effective.