Research On The Coupling Chanracteristics And Material Ablation Experiments Of Water-jet Guided Nanosecond Laser Processing

With the continuous progress of laser processing technology,various laser composite processing technologies are also developing.Among them,laser-jet coupling processing technology has broad application prospects.In this paper,the coupling characteristics and the behavior of ablating materials of water guided nanosecond laser are studied.The interaction between laser,water and materials under different parameters in the coupling process is analyzed.Firstly,the characteristics of the coupling region between nanosecond laser and jet are studied,and the evolution of free electrons with time is obtained.The relationship between laser wavelength,pulse width and breakdown threshold is summarized,and the corresponding experimental verification is carried out.The development process of free electron density in the focusing region under different pulse widths is described.On this basis,a method of controlling laser time-domain pulse sequence is proposed.Relevant experimental studies have been carried out on the causes of bubbles in the coupling chamber,and the conclusion that pressure can suppress this phenomenon has been verified.Subsequently,the characteristics of the jet of water guided nanosecond laser are studied.A device for measuring the stable length of the jet is designed and built.The law of the change of the stable length under different pressure and different coupling power is explored.The laser energy distribution of the cross section of the jet is explored,and the conclusion that the coupling of jet can improve the laser energy distribution is verified.The model of jet impact process was established,and the scouring effect of jet on the processing area was explored.Finally,the experiments of ablating materials of water guided nanosecond laser were carried out,and the grooving experiments of 304 stainless steel,silicon carbide and silicon were carried out.The processing effects under different pressures were investigated,and the groove morphologies of different processing methods were compared.The application range of water guided nanosecond laser processing materials was summarized,and the advantages of water guided nanosecond laser processing were verified.Aiming at the complex processing environment of water guided nanosecond laser,this paper explores the related characteristics of the focusing area,jet and the processing area of nanosecond laser-jet coupling,combining theoretical analysis and experimental research,which provides theoretical support for the overall application of laser-jet combined processing.