Drawing Technique And Method Studies On The Ultra-fine Diamond Busbar Drawing With Ultrasonic Vibration

In recent years,the rapid development of domestic photovoltaic industry has promoted the transformation and upgrading of related industries,such as silicon wafer manufacturing,silicon wafer cutting and the demand for silicon wafer grows rapidly.The diamond wire saw cutting method has the highest production capacity and the widest range of applications currently,but there still have many defects,such as poor mechanical properties and surface quality,easy to break,which have great influence on the continuous cutting silicon processing.Previous studies have shown that ultrasonic vibration drawing method can reduce the drawing stress and homogenize residual stress,as well as improve surface quality.So this article design a kind of ultrasonic transducer which can assemble with wire drawing machine based on the actual drawing production conditions and study the theory,simulation and experiment of drawing for ce,coil diameter,surface quality and temperature,finally propose a method to improve the diamond saw.In terms of theoretical research,the isotropic strain rate were calculated by decommissioning the velocity,and then the internal deformation energy,friction energy and shear strain energy were calculated in the deformation process.The input power was equal to the power consumed,so the formula of the tensile principal stress could be obtained.The radius reduction zone was regard as a conical heat source model,by which the temperature rise of each point in the region could be calculated.Then the stress and temperature formulas were analyzed by software,and the impact effects of each parameter were determined.The finite element model of drawing pro cessing zone was established and contact simulation analysis in three different loading methods were carried out to obtain the information of drawing stress strain,friction force and coil diameter.The results showed that both elastic deformation and plas tic deformation occurred in the drawing process,and the value of plastic deformation was large r,while the plastic deformation couldn't be affected by ultrasonic vibration.Ultrasonic vibration could reduce the drawing force and increase the coil diameter,but it could also increase the friction stress in the non-ideal condition.In the processing zone of the wire,the temperature decreased from the surface to the center,and the maximum temperature could reach about 90°C.The longitudinal ultrasonic transducers were designed and its modal,harmonic response and transient analysis were done.The impedance characteristic,frequency characteristic and speed output characteristic of the transducer were measured.The ultrasonic transducer was installed on the wire-drawing machine for the experiment,and the wire were tested by using the roundness measuring instrument,thermal imager and scanning electron microscope etc.The results showed that ultrasonic vibration could significantly reduce the drawing force and slightly increase the coil diameter.The temperature of the transducer was mainly concentrated at both ends,while the maximum temperature was less than 50°C,which would not affect the continuous working performance of the transducer.Ultrasonic vibration could homogenize the surface of the wire.Besides,the thermal effect in the drawing process promote d the oxidation of the wire and the penetration of carbon on the die.