Research On Factors Affecting Tension Fluctuation Of Sapphire Multiwire Sawing Machine

Sapphire is a typical material of hard and brittle,which has been widely used in electronic equipment,military equipment,medicine and other fields due to its unique crystal structure and excellent mechanical and optical properties.As an indispensable part in the production and processing of sapphire substrate,the precision of tension control of sapphire multiwire sawing machine can affect the surface quality of sapphire wafers directly.Clarifying the composition of influencing factors of tension fluctuation in sapphire multiwire sawing machine so that we can take measures more effective to deal with the problem of tension fluctuation,improve tension control accuracy,reduce material loss and extend the service life of the machine.This is also conducive to develop the multiwire sawing technology in China,break the foreign technology monopoly,and improve the competitiveness of domestic slicing equipment for hard and brittle materialsBased on the analysis above,the following research work is carried out in this paper:Based on the analysis of relevant domestic and foreign literatures and the investigation of equipment manufacturers and users of sapphire multiwire sawing machine,the working principle of sapphire multiwire sawing machine is analyzed and the control system model of sapphire multiwire sawing machine is established.Make the two keys of the control system clear:（1）regard the tension arm Angle θ8 as the closed-loop feedback quantity to get release rollers can follow the linear velocity of working rollers well.（2）on the basis of this,the tension pulley D in its value as a closed-loop feedback tension control of the motor output torque so as to realize the on-line tension stabilityThrough model analysis,four groups of potential factors affecting tension fluctuation were determined:load disturbance of working roller C1;Angular acceleration α₃ and angular jerk α₃ of Working roller C1;The tracing error rate Δv and the tracing error jerk △v of linear velocity in the motor synchronization system;Intrinsic parameters of each module.Then,based on the working principle of sapphire multiwire sawing machine,simulation analysis was carried out on these factors and their mechanism was studied.The influence of these factors on the on-line tension was evaluated from two dimensions:the amplitude of tension fluctuation and the fatigue level of diamond wire.Based on this,the paper proposes some measures to reduce the tension fluctuation,such as optimizing the reciprocating linear velocity curve,simplifying the wiring system of the storage room,strengthening the lubrication of the tension pulley module and guide pulley,and adopting appropriate mechanical structure and part parameters.Finally,the experimental study of angular jerk α₃ and angular acceleration α₃ of working roller C1,which are the main factor of tension fluctuation,verifies the correctness of the simulation results.It is proposed that in designing the reciprocating linear velocity curve,we should reduce the Angle jerk α₃ and improve the angular velocity α₃ as much as possible under the premise of satisfying the technological requirements,so as to obtain the tension fluctuation optimization measures of smaller tension peak,better tension stability and higher cutting efficiency.