Research On Finite Element Simulation And Experiment In Waterjet Assisted Laser Machining Wood

With the improvement of people’s living standards,the demand for refined wood products is increasing.Waterjet assisted laser machining technology has some advantages of no pollution,high machining accuracy and good surface quality in the manufacturing process,which is in line with the trend of green manufacturing and has a broad application prospect.Most researches are waterjet assisted laser machining metals,ceramics and other materials at home and abroad.Because the waterjet assisted laser cutting improves machining accuracy and surface quality,it has been widely concerned,which has opened up a new way for the fine process of wood.However,there are great differences between the waterjet assisted laser cutting wood and the traditional laser processing in physical and chemical properties of metals and ceramics,so it is necessary to study the machining principle,machining mechanism and cutting quality of waterjet assisted laser machining wood systematically.In this paper,a new process of waterjet assisted laser machining wood was proposed.The machining principle of waterjet assisted laser cutting wood was studied,and the synergistic effect of laser energy and waterjet on wood processing was discussed.The interaction mechanism of laser,waterjet and wood was studied,and cutting mechanism of waterjet assisted laser machining wood was revealed.Furthermore,the platform of waterjet assisted laser machining wood was built.Trial cutting experiment was conducted,and then Korean pine and northeast China ash wood were selected to be the objects of subsequent finite element simulation and experiment.On the basis of numerial simulation theory of waterjet assisted laser machining wood,the heat transfer model and boundary condition of waterjet assisted laser machining materials were established.Based on the analysis of common heat source models in laser processing simulation,a compound heat model suitable for wood processing was established.DFLUX subroutine of ABAQUS was used to load and control the laser heat source.Using the finite element method and ABAQUS software,the energy heat transfer characteristics,heat source model and heat source trajectory control mode were analyzed,a three-dimensional finite element analysis model of wood was established.Moreover,the temperature field simulation of the process of waterjet assisted laser machining Korean pine was analyzed,then the temperature field distribution and change rule were obtained.The influence of processing parameters on the ablation area,temperature field distribution and change rule of waterjet assisted laser machining Korean pine were discussed.The simulation results of temperature field were verified to determine the rationality of finite element model,load and boundary conditions.Korean pine,softwood,was used as test material.Comparing and analyzing the kerf width,surface roughness,surface composition and surface micromorphology of Korean pine cut along and cut into perpendicular to the fiber by traditional laser processing and waterjet assisted laser processing,through single factor experiment,theinfluences of waterjet assisted laser processing parameters on the kerf width and surface roughness of Korean pine were analyzed.With the five factors and four levels of orthogonal experimental design method,taking the kerf width of Korean pine parts as the index,the process parameters of waterjet assisted laser processing were optimized to obtain the optimal process parameters of waterjet assisted laser cutting Korean pine,and through the analysis of the micro morphology of the kerf surface of Korean pine,good kerf surface quality of Korean pine using optimized process parameters was obtained.Taking northeast China ash wood,hardwood,as the research object,the cutting quality of northeast China ash wood cut along and cut into perpendicular to the wood fiber by traditional laser processing and waterjet assisted laser processing was compared and analyzed.Through single factor experiment,the influences of the process parameters of waterjet assisted laser processing on the kerf width and surface roughness of northeast China ash wood were analyzed.Taking surface roughness as the index,response surface method was used to optimize the process of waterjet assisted laser processing of northeast China ash wood.The prediction model and the optimal process parameters of the surface roughness of northeast China ash wood were obtained.Under the optimal process parameters,cutting experiments were carried out.Through micromorphology and three-dimensional shape morphology of the kerf surface,it is verified that the established secondary mathematical model describing the relationship between the surface roughness and cutting parameters has a better prediction effect,which is helpful to select the appropriate process parameters for the required cutting quality.