Study On Laser Circular Cutting Hole-Making Process Of Laminated Al Alloy Sheets

With the development of lightweight technology,a variety of new lightweight materials,such as titanium alloy,aluminum alloy,magnesium alloy,carbon fiber composite materials,are more and more widely used.Especially in the aviation field,aluminum alloy is still the first choice of materials,such as aircraft skin,stringer,partition frame and so on.Aluminum alloy is mainly connected by riveting and bolts,among which drilling is an indispensable and important process.In order to improve the assembly accuracy and efficiency of the aircraft,multiple connectors are needed to make holes at the same time,so the hole making process of laminated plates is particularly important.In order to improve the defects such as interlayer delamination,tool wear and sticking knife in the mechanical hole making of laminated sheet,a new method of laser circular cutting hole making is proposed.The process of laser cutting laminated aluminum alloy sheet is studied,and the quality of hole making is controlled by controlling the process parameters.The main research contents are as follows:(1)The laser processing mechanism of laminated plates was studied.The finite element model of laminated aluminum alloy plates was established.The laser circular cutting hole making process of laminated aluminum alloy plates was numerically simulated.The Gaussian body heat source was applied to the laminated plates in the form of command flow.The temperature field distribution under different time periods,positions,apertures,spot radii and laser parameters was studied.The influence of laser parameters on the upper aperture,the upper aperture,the lower aperture and the lower aperture is obtained.(2)The single factor test method was used to carry out the laser circular cutting hole making test of laminated aluminum alloy sheet.Considering the influence factors such as laser power,scanning speed,defocusing amount and auxiliary air pressure,the influence of the above factors on the upper cone angle,lower cone angle,the difference between the upper and lower aperture and the heat affected zone of the hole making was analyzed.The effective range of each factor with good hole making quality was obtained,which further verified the validity of the simulation results.(3)The multi-factor test of laser circular cutting hole making of laminated aluminum alloy sheet was carried out by response surface method.The multi-factor test scheme was designed.The quality evaluation target of laminated aluminum alloy sheet after the test was measured.The mathematical model of each response target was established.The multi-factor interaction law was analyzed,and the optimal process parameter group and target prediction value after multi-objective optimization were obtained.The effectiveness of the optimized process parameter group and the feasibility of obtaining the optimal circular cutting hole making quality were verified by experiments.