Research On Key Technology Of Three Dimensional Laser Cutting Corner And Clearance Plate

The traditional processing methods is gradually replaced by the three-dimensional laser cutting technology with it's high flexibility and smooth feature in the field of sheet metal processing.Not only production efficiency is to be improved,but also the high-quality cutting requirements,the three-dimensional laser cutting process optimization under special conditions and Technological development study is needed.In this paper,process optimization and experimental research are carried out around the two-dimensional laser cutting conditions of corner cutting and variable gap plate.The main research contents are as follows:?1?A theoretical analysis of the 45-dimensional laser cutting process of 45 steel was carried out.Based on the interaction mechanism of laser and metal materials,the process of melting,gasification,formation of small holes and plasma changes on the surface of the laser and the material was analyzed.Laser gasification cutting,laser melting and cutting,reaction melting and laser cutting were discussed.Slices,controlled fractures,cold cutting,and thermal stress cutting five cutting models.The cutting process of oxygen-assisted laser cutting of 45 steel was studied:in the first stage,a laser beam with high energy density was irradiated on the surface of 45 steel,and the surface temperature increased to reach the ignition point of the steel plate;in the second stage,oxidation reaction of O₂ with the steel plate occurred.The steel plate absorbs a large amount of heat energy released from it and melts.In the third stage,the steel plate is cut open with the relative movement of the laser beam and the surface of the steel plate.The effects of laser power,cutting speed,focal position,incident angle of light beam,and assist gas on the quality of 3D laser cutting are further analyzed.The dimensional accuracy of the workpiece after laser cutting,the surface quality of the workpiece and the macroscopic appearance of the workpiece are proposed.Assessment of the quality of the comprehensive evaluation of cutting ideas.?2?The process optimization and cutting quality analysis of the laser cutting rotation angle were carried out.The phenomenon that the laser beam was dense at this point,the energy concentration,and the small heat dissipation area at the corner of the three-dimensional laser cutting was analyzed,and the"three steps"of partitioning,reducing the processing points at the corners,and optimizing the process parameters were proposed.Method to avoid the process idea of corner burn.Based on this,a process optimization study was conducted,N₂ and O₂ auxiliary gases were used,and orthogonal experiments were performed using three factors,namely laser power,cutting speed,and auxiliary gas pressure,and the cutting quality was compared and analyzed.The research shows that the laser power is 600W,the cutting speed is 25mm/s,and the auxiliary gas O₂ pressure is 0.21Mpa.After the optimization of the process,the cutting section is flat,there is little slag,and no overburning occurs.The width of the kerf is affected by the laser power and cutting.The influence of speed is greater,and the roughness of the cutting section is affected by factors such as laser power,cutting speed,and auxiliary gas type.The width of the kerf increases with the increase of the pressure of the auxiliary gas O₂.The width of the kerf The size does not change significantly with the increase of N₂ pressure.The influence of O₂ assist gas on the heat affected zone near the kerf is larger than that of N2 assist gas;at pulsed laser power p=600w,duty cycle=60%,frequency f=300HZ,cutting Velocity v=20mm/s,focus position h=+1.5mm,O₂pressure=0.18MPa,more fringes on the cut section,surface roughness21.872?m,continuous laser power p=800w,cutting speed v=30mm/s,Focus position h=+1.5mm,O₂ pressure=0.24MPa,less fractural cross section,smooth surface,less dross,surface roughness 19.657?m,different laser modes can be selected to avoid corners Burning phenomenon,pulse excitation Cutting corner selecting a smaller laser power,the slower the cutting speed and cut quality of the obtained duty ratio to 60%better.?3?Analyze the three-dimensional laser cutting model of variable gap plate,and optimize the process and experimental study.Taking 3mm thick 45 steel as the research object,based on the influence of process parameters?laser power,cutting speed and focal point position?and the size of gap between plates on the cutting quality of laser-cutting variable-gap sandwich plates,the process optimization and experimental study were carried out.Studies have shown that:based on a good cutting quality of the upper and lower plate gap limit size of 2mm,when the plate gap is greater than 2mm,the lower section of the cutting section roughness,heat affected zone width have a significant impact on the quality of the upper plate cutting The impact is not significant;the limit distance of the gap between the upper and lower plates that can be cut through is 6mm.When the gap between the plates is greater than 6mm,the lower plate cannot be cut through.