| Diamond wire sawing technology has gradually replaced free abrasive wire sawing technology in the field of silicon wafer cutting due to its high efficiency,cutting speed and precision.However,the surface quality of polysilicon wafer is poor due to the complexity of polysilicon crystal structure when cutting polysilicon with diamond wire sawing,which increases the subsequent processing cost.In this paper,in order to improve the lubrication cooling effect of cutting fluid and surface quality of wafers,electrostatic spraying liquid supply is used instead of pouring liquid supply in diamond wire sawing.The dynamic characteristics of charged droplets before entering the cutting area,the adsorption of charged droplets on the diamond wire surface under different atomization parameters,and the experiment of diamond wire sawing under two liquid supply modes were studied.（1）The dynamic model of the charged droplets before entering the cutting area was established.The mechanical analysis shows that the physical parameters that affect the dynamic behavior of charged droplets are:the diameter,velocity and charge of droplets,electric field intensity and gas velocity.These physical parameters are determined by the atomization parameters（charging voltage,atomization air pressure and flow rate）.（2）According to the dynamic analysis of the charged droplet before entering the cutting area,the simulation model was established.The influence of different atomization parameters on the adsorption of charged droplets was studied by using the finite element software COMSOL Multiphysics.The results show that the increase of the charging voltage,atomization air pressure and flow rate can help to the adsorption of cutting fluid on the diamond wire surface.But the excessive atomization air pressure is not conducive to the adsorption of charged droplets on the diamond wire surface.（3）An electrostatic spraying cutting fluid adsorption experiment device was built,and the adsorption experiment of charged droplets was carried out.The results show that the cutting fluid adsorbed on the diamond wire surface increases gradually with the increase of charging voltage and flow rate.And the cutting fluid adsorbed on the diamond wire surface increases first and then decreases with the increase of atomization air pressure.The results of adsorption simulation and experiment show that under different influence factors,although the adsorption mass of charged droplets measured by experiment is different from that of simulation,its change rule is consistent.（4）Combined electrostatic spraying system and WXD170 reciprocating diamond wire rotary point cutting machine,an experimental platform for electrostatic spraying diamond wire sawing was built.And diamond wire sawing experiment with two kinds of liquid supply modes were carried out.The experimental results show that the charging voltage is the main factor affecting the cutting quality,and the cutting quality increases with the increase of the charging voltage.The cutting quality first increases and then decreases when the atomization air pressure increases from 0.14 MPa to 0.2MPa.And the increase of flow rate can improve the cutting quality,but there is saturation value.When the atomization parameters are-6 k V,0.16 MPa and 2.5 ml·min-1,the cutting quality of the electrostatic spraying diamond wire sawing achieves the best.Compared with the pouring liquid supply,the edge breakage width is reduced by45%,and the surface roughness is reduced by 24%. |
