Study On The Influence Of Low Pressure Water Jet Assisted Laser Etching On Jet In Silicon Carbide

When the traditional laser processing technology processes hard and brittle materials such as ceramics,there are inevitable problems such as recast layer,slag,and heat affected zone.The usual laser processing often uses assist gas to help to support combustion and remove,but the effect is not satisfying.In order to solve these problems,the article has introduced low-pressure water jet assisted laser processing technology.We used the impact and cooling effect of water jet to reduce the heat affected zone to reduce the generation of micro cracks,the recast layer and improve the processing quality;The offaxis jet device is simple in design,cost-saving,and more scalable,and can be applied in actual production and processing.However,the introduction of water jets,the reduction of heat-affected zones and the generation of impacts can lead to the loss of energy originally used for processing materials.When the velocity of water jet is large,the continuous jet of the water jet will generate a layer of water mist on the workpiece.The laser contacts with the water mist may cause multiple focusing,affecting the original laser energy,so it is necessary to determine the speed of the jet and the cooling effect of the jet.The specific relationship between the cooling and impact of jets at different speeds and angles needs to further study.The main research contents of this paper are as follows:(1)On the basis of understanding the interaction between laser and material,the cooling and impact of the jet in the composite machining process are discussed.Through theoretical analysis and formula deduction,the influence of the jet velocity and the impact angle on the impact of the jet and the cooling effect are obtained.(2)The finite element software FLUENT was used to simulate the process of impacting the water jet on the plate,and the pressure of the plate under different inclination angles,different efflux velocity was obtained.The jet speeds chosen for this article are 7,12,17,and 22,and the jet incident angles are considered to be 30° and 60°,respectively.The water convection heat transfer process in water jet-assisted laser machining is appropriately simplified to simulate the convective heat transfer conditions of the heated silicon carbide plates with different jet tilt angles and efflux velocity,and the variation of the convective heat transfer coefficient between the water jet and the silicon carbide plate is simulated curve.(3)Study the heat conduction mechanism in the laser processing process,and establish a corresponding laser heat source model according to the actual situation,determining the appropriate boundary conditions according to the actual situation,using the finite element software ABAQUS to simulate the jet assisted laser etched silicon carbide flat plate.The distribution of temperature field was obtained,combined with the effect of impact force and convection heat transfer at different jet velocities,the variations of the depth and width of the groove body obtained by etching at different jet velocities were analyzed.(4)Using a jet-laser compound processing system to etch silicon carbide flat plates,comparing the results of water-free conditions,and analyzing the etching conditions corresponding to different jet velocities under various laser process parameters.The influence of the differents of water jet velocity on the laser etching results under the determined laser process parameters are obtained.