本研究主要探討光罩式投影Nd-YAG(1064nm)雷射鑽孔成形，以數值分析與實驗方法研究圓形光罩、透鏡光圈直徑及雷射脈衝寬度對微孔輪廓之影響。於數值模擬方面採用自行撰寫之數值程式，分析光罩式投影鑽孔成形中考慮繞射現象時，不同入射光模態、光罩及透鏡光圈直徑下，靶材表面能量輪廓之變化；另以流體計算軟體FLUENT模擬鑽孔時靶材熔池之流場特性，探討雷射功率與流場特性之關係。實驗上以高斯模態之綠光雷射(532nm)模組及光束輪廓分析儀進行雷射能量分佈之量測，藉由改變光罩、透鏡光圈直徑，觀察能量分佈之差異；並以Nd-YAG脈衝雷射進行PMMA靶材之投影鑽孔加工，同時藉由改變光罩、透鏡光圈直徑及脈衝寬度，觀察微孔斷面特徵形貌之差異。
經由數值分析與實驗結果後發現，高斯模態與均勻分佈雷射之入射光於能量輪廓頂部有明顯差異，藉由提升雷射功率及脈衝寬度時可以達到更平滑之微孔底部輪廓，增加光圈直徑與雷射功率時會使微孔邊緣隆起寬度等特徵尺寸增加；在光罩、光圈直徑遞減時，光束能量輪廓與微孔斷面形貌皆受繞射現象之影響而產生愈大的失真現象。

The aim of this study is to analyze the hole-shaping of Nd-YAG laser (1064nm) drilling with the mask projection method, and the effects of circular mask and aperture diameter on hole-shaping have been investigated numerically and experimentally. In the numerical analysis, a computation model was developed to analyze the intensity profile on the image plane at various optical parameters based on Fourier diffraction theory. The flow field of melting-pool on the substrate at various laser intensities was simulated. In the experiment, the green laser (532nm) with Gaussian mode was used as the light source, and the intensity profiles were measured by laser beam profiler. Finally the PMMA targets were drilled by Nd-YAG pulsed laser with mask projection method at various optical parameters.

It was shown that the uniform distribution and Gaussian laser modes have different diffraction profiles on target surface. It can be found that smoothness of the hole-bottom increases with the laser intensity and duration time, furthermore the hump width of drilling inlet holes increases with the laser intensity and aperture diameter. Both the numerical and experimental results show that the decrease of mask and aperture diameters will enhance the diffraction distortion at intensity profiles on the image plane and hole-shaping.

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