Study On Laser-assisted Cutting Performance Of Fused Silica

Fused silica is an amorphous solid consisting of high purity silica.This amorphous structure gives it excellent physical and chemical properties,mechanical properties and optical properties.At present,fused silica has been widely used in optical devices,precision instruments and aerospace fields.However,due to its high hardness,high brittleness and low fracture toughness,tool wear is serious in traditional machining,and surface defects are easily caused.Laser-assisted cutting technology can effectively reduce the strength and hardness of workpiece materials,and enhance its plastic flow characteristics,thus reducing tool wear and surface defects,providing a new solution for high-quality processing of fused silica.In this paper,laser-assisted cutting of fused silica is studied as follows:Firstly,the cutting simulation model of fused silica was established by using smooth particle hydrodynamics(SPH).The dynamic cutting process at high and normal temperature was analyzed,and the chip shape and cutting force were compared.The simulation results show that under high temperature,cutting force decreases,plastic fluidity of workpiece material increases,chip morphology gradually changes to continuous mode,and high temperature relieves stress concentration in cutting process.It is advantageous to the high quality forming of fused silica which is a brittle material.Secondly,the feasibility of laser-assisted cutting fused silica is studied experimentally.Based on orthogonal experiments,the processing effects of conventional cutting and laser assisted cutting are compared.The experimental results show that the tool wear decreases by38.79%,the three-dimensional cutting force decreases by more than 50%,the surface roughness of the workpiece decreases by 65.86%,the chip morphology changes from powder to semi-continuous,and the material removal rate is effectively improved.It provides an effective technological support for rapid prototyping of fused silica with high quality and low damage.Lastly,the effects of laser power,feed speed and cutting speed on the surface roughnessand cutting force of fused silica workpiece are investigated through full factor experiments.The experiments show that the roughness and cutting force have the same changing law,that is,they decrease with the increase of laser power,increase with the increase of feed speed and decrease with the increase of cutting speed.Subsequently,the processing performance of different cutting tool materials in laser-assisted cutting fused silica glass was explored through experiments.The experimental results show that the polycrystalline diamond(PCD)tool can obtain smaller cutting force and higher wear resistance than the polycrystalline cubic boron nitride(PCBN)and coated ceramics(T66N)tool.It is conducive to mass production of high quality fused silica in advanced industrial applications.