本研究首先以工業技術研院雷射與積層製造科技中心提供之選擇性雷射燒熔(Selective laser melting, SLM)單道次列印試件為基礎，分析各加工參數的熔融區域與單道次列印凝固後之表面形貌。隨後以COMSOL Multiphysics多重物理量耦合模擬軟體建立選擇性雷射燒熔的分析理論。
在本研究中，將相變化熱傳方程式匯入古典熱傳方程式，再建立過渡式雷射體積熱源模型(Transient laser volumetric heat source model)，模擬雷射光源對金屬粉末、液態金屬與蒸發後氣化區域的影響。使得本研究的雷射體積熱源模型可適用於選擇性雷射燒熔中更廣泛的加工參數範圍。且在本研究中，熔池寬度和熔池深度的理論值除了與實驗量測值有相似的趨勢外，此兩個熔池尺寸理論值與實驗值的誤差百分比亦介於5~20%之間，進而改善了以往研究中對於熔池尺寸的數值分析有著較高誤差的情況。
在熱傳模組(Heat transfer modle)計算出的溫度解為基礎之上，本研究於相位場模組(Phase field model)中模擬金屬熔池因表面張力而聚合之流體情形方面，經由對蒸發區域設定合理的金屬熔池回補(Refill)情形，即可有效降低堆積高度中理論值與實驗值的誤差百分比，進而提高加工參數對於堆積過程影響的了解。
最後，則是比較單道次(Single track)列印之實驗結果與單層面(Single layer)列印之實驗結果，以分析單道次列印對於多道次列印產生之影響。並得知較大的深寬比與較小的金屬熔池與基板接觸角，可降低選擇性雷射燒熔列印後的平均粗糙度(Sa)，進而提高列印後的表面品質。

In this research, we first did the analysis of melting region and surface profile on single track experiment samples by selective laser melting(SLM) from ITRI for stainless steel SS316L.After the analysis of experimental sample, we built the numerical model for SLM with COMSOL Multiphysics by separating the temperature field and fluid field in numerical model, to simplify the analysis process in selective laser melting. We first used the laser volumetric heat source mode to calculate the temperature field in heat transfer model with the simulation of laser beam interacting with powder bed, melting pool and vaporization region. The error percentage between theoretic and experimental values for melting track width and depth in our research was in a range of 5~20%. Based on the solution of temperature field, we used phase field model to simulate the gathering process of melting pool driven by surface tension, and get the solidification height by the appropriate assumption for refilling mechanism in vaporization region. Finally, we compare the experiment results of single track to single layer, and found out the relationship between surface quality of single layer with the melting pool dimensions of single track. We get the result that with the higher value of aspect ratio and smaller contact angle of melting pool with substrate, the surface roughness will be smaller, and we can get the better surface quality in single layer of SLM.

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