Femtosecond Laser Micromachining Of Biomedical Polymer

Micromachining with femtosecond laser has been popular among micromachining.Machining of micro devices based on biomedical polymer with femtosecond laser has a very good application prospect.This paper works on micromachining of biomedical polymer with femtosecond laser,aiming at researching the machining mechanism.The contents of this paper include:1.Illustration of the property of micromachining with femtosecond laser with examples of metal and transparent dielectric.Summarization of the research on femtosecond laser machining of polymer and properties and applications of biomedical polymer.2.Simple statements on the mechanism of interaction of laser and polymer.Illustration of photo-physical process based on molecular orbital,such as transition,energy conversion,energy transfer,electron transfer.Classification of the mechanism into photo-thermal effect and photo-chemical effect,which cause the acceleration of relaxation transition and degradation.3.Experiments of machining on PMMA with high-repetition-rate femtosecond laser source and machining system.Tests of results with SEM,IR spectroscopy and Raman spectroscopy,with outcomes that ablated area is clean,new peak of carbon-carbon double bond appears on IR spectroscopy,high background photoluminescence appears in Raman spectroscopy,and the conclusion that heat effect is dominate and PMMA experiences thermal degradation.4.Comparison of machining on PLA in air and underwater.Tests of results with SEM,IR spectroscopy,Raman spectroscopy and XPS,with outcomes that ablation in air comes along with melts,i.e.not complete,while under water there is no trace of melt but random porosity,hydroxyl peak increases in IR spectroscopy,almost no background photoluminescence appears in Raman spectroscopy,relative content of oxygen increase by XPS,and the conclusion that with certain laser fluence,PLA experiences hydrolysis when under water.