레이저 드릴링을 통한 강판 가공 시 응력 모델링

Abstract

Key Words: Topology Laser Drilling(레이저구멍가공), Hole-Drilling Method(홀드릴링기법), Stress(응력)초록: 레이저정밀가공은고품질의집속광에너지를이용하여재료를미세하게가공하는특수가공으로정밀제조분야에적용되고있다. 그러나레이저가공시열적효과로인해재료특성을저하시킬수있다. 또한, 압연강재및강판의경우공정단계에서강한압력으로제작하기때문에반드시잔류응력이존재한다. 하지만압연강재에존재하는잔류응력의양은정량적인예측이불가능하다. 이러한잔류응력이존재하는재료의레이저가공시레이저에의한부가적인응력발생및재료에미치는열적영향의예측및평가는정밀가공에있어서반드시고려해야하는사항이다. 본연구에서는레이저홀가공시발생되는온도및응력을유한요소해석과실험적방법으로분석하였다. 재료의열응력을예측하기위해레이저홀가공실험을수행하여가열및냉각등의대한결과를도출하였다. 또한냉각시간에따른응력의변화를파악하였고유한요소해석으로예측된응력을홀드릴링응력측정기법에의해도출된응력과비교검증하였다.Abstract: A laser machining process has been applied in many manufacturing fields and it provides anexcellent energy control for treating materials. However, a heat effect during laser machining can deterioratematerial properties. Specifically, a thermally induced stress can be a problem in laser-machined structures ona metal surface. In this study, temperature and stress on cold-rolled carbon steel sheet machined with laserhole drilling were explored in an experimental approach and a numerical method. Stresses by temperaturegradients inside the materials were generated in fast cooling. The stresses were measured by using ahole-drilling method and the material properties of carbon steel (SCP1-S) were obtained in the experiment. Itwas found that the stress predicted from the numerical analysis was in agreement with the stresses measuredby using the hole-drilling method. The analysis can be applied for evaluating structure characteristicsmachined with a laser.