Design Of Tension Control System For Polysilicon Cutting Machine

With the rapid development of semiconductor industry and photovoltaic solar industry,silicon wafer is widely used.The production efficiency and precision control of traditional cutters are far from meeting the needs of wafer production.Because of this,in this thesis,the tension control system of polysilicon cutting machine is designed,Two methods of open loop control and closed loop control for tension of diamond wire are studied and put into practical application.The control system consists of an Omron NX102 motion controller,NA touch screen,servo system,sensors,and so on.NX realizes multi-axis servo control through Ether CAT communication and adjusts the torque or speed of the servo motor to achieve tension control.The NA touch screen and NX are connected through Ethernet /IP network to realize the action control,parameter setting,status monitoring,and data display of the truncator.The main work of this thesis is as follows:(1)The research background,purpose and significance of polysilicon chopper and its research status at home and abroad are introduced.According to the mechanical structure and cutting process of the cutting machine,the hardware required by the control system is determined and selected(2)The open-loop tension control algorithm and the closed-loop tension control algorithm are designed to control the tension of the diamond wire.The linear tension mathematical model is established according to the relationship among tension,torque,and coil diameter,and the calculation of the compensation of reel diameter,reel speed,accumulated thickness,and inertia moment is studied in the open-loop control algorithm.The open-loop control is mostly applied to the situation where the absolute precision of tension is not high.Based on the open-loop control algorithm,a closed-loop tension control algorithm was designed.The tension of the diamond wire was directly measured by the tension detection device using the PI control method.The closed-loop control was realized as feedback quantity,and the taper tension compensation was added to improve the precision and stability of the tension control.(3)According to the cutting process flow diagram,write the controller running program using the Sysmac Studio software.The initialization program,the automatic control program,the manual control program and fault alarm program are included;Through writing the NA touch screen parameter monitoring interface,parameter setting,alarm log,and so on,the simple and intuitive control and management of the polysilicon cut-off machine are realized.The tension control system of the polysilicon truncator designed in this topic has realized the cutting requirements of high speed and high precision,the highest line speed can reach 12m/s,the tension fluctuation range is controlled within ±5%,and can maintain the stability of the tension for a long time,to meet the design requirements,and has monitoring,alarm,and other security functions.The system has been applied in actual production and put into the production line of a cutting equipment factory in Qingdao.