Research On Pico-second Laser And Micro-drilling Technology

With the rapid development of laser technology, ultra-short pulsed laser has beenwidely applied in the field of metal micro-machining. Especially, pico-second pulsedlaser has become a hot research point for its stable working characteristics and highquality of materials processing in recent years. In order to make a further explorationof the mechanism and processing technology of ablation on metal material bypico-second laser, this paper has carried out the following works.First of all, the basic principles of laser drilling and the interactive regulationbetween laser and material are analyzed theoretically. According to one-dimensionaltwo-temperature model, detailed analyses of properties with different laserpulses-width in the ablation material are discussed, respectively. At the same time, acomputer controlled pico-second laser precision machining system which is based onan independently developed all-solid-state kHz pico-second laser and a four axisprecision displacement platform is designed for ablation experiments.By using the pico-second laser precision machining equipment， ablationexperiments in stainless steel, titanium, and molybdenum are taken, respectively，inorder to get the single pulse and multiple pulse ablation thresholds of the three kindsof materials. On this basis, a large number of drilling experimental studies in themetals are taken, variables including: laser parameters, drilling method, protection gasand so on. Based on the analysis of experimental results, we have optimized the laserdrilling parameters and processing methods which would provide important referencedata for the industrial application of pico-second laser precision machining.Ultimately, the high quality micro-holes of metal by percussion drilling andpercussion drilling on the Mo with protective gas, and the diameter of50μm and200μm are obtained, respectively. And some pores of200μm diameter have been takenby helical drilling in a1mm thick stainless steel plate.