本研究以雷射箔材列印技術（Laser Foil Printing, LFP）製備 316L 不鏽鋼零件，並探討其機械性質、微結構特徵及嵌入 PVDF 壓電感測器之可行性。LFP 製程以金屬箔材作為原料，透過連續式雷射進行點焊與圖形焊接，再利用脈衝雷射進行輪廓切割，完成逐層堆疊成形。本研究使用厚度 0.2 mm 之 316L 不鏽鋼箔材，並透過自製雙雷射系統成功製備相對密度達 99.9% 之試片。拉伸試驗結果顯示，LFP 製備之 316L 不鏽鋼在 X 方向具有較高強度，其降伏強度與極限抗拉強度分別為 544.1 ± 8.7 MPa 與 696.4 ± 6.1 MPa；而 Z 方向則展現較佳延展性，伸長率可達 90.1 ± 3.6%。SEM 斷口分析顯示試片皆呈現韌性斷裂特徵，並可觀察到 dimple 與 micro-void 結構，與其高延展性結果相符。XRD 分析確認試片主要由 FCC γ-austenite 相組成，未觀察到明顯 BCC ferrite 峰值。EBSD 結果顯示 XY 平面具有細小且均勻之等軸晶，而 YZ 截面則呈現沿建構方向成長之柱狀晶，顯示 LFP 製程中熱梯度與凝固方向對晶粒形貌及織構具有明顯影響。此外，硬度測試結果在水平方向為 248.3 ± 6.0 HV，在垂直方向為 228.3 ± 5.0 HV，顯示材料具有穩定之機械表現。最後，本研究依據 PVDF 感測器尺寸設計 14 × 19 × 0.36 mm³ 嵌入槽，並透過分區掃描策略降低熱累積，以減少感測器受熱損傷風險。總體來說，LFP 不僅可製備高緻密度且具良好強度與延展性之 316L 不鏽鋼零件，也展現出應用於金屬結構內部感測器整合與智慧化製造之潛力。

This study investigates the microstructure, mechanical properties, and feasibility of embedding polyvinylidene fluoride (PVDF) sensors in 316L stainless steel components fabricated by laser foil printing (LFP). In the LFP process, metal foils are used as feedstock and are sequentially joined by laser spot welding and pattern welding, followed by pulsed-laser contour cutting to define the geometry of each layer. In this work, 0.2 mm-thick 316L stainless steel foils were processed using a homemade dual-laser LFP system. Dense 316L stainless steel specimens with a relative density of 99.9% were successfully fabricated, demonstrating the capability of LFP to produce high-quality metallic components.
The mechanical properties of the fabricated specimens were evaluated by tensile testing along the X and Z directions. The X-direction specimens exhibited a yield strength of 544.1 ± 8.7 MPa, an ultimate tensile strength of 696.4 ± 6.1 MPa, and an elongation of 72.9 ± 1.8%. In contrast, the Z-direction specimens showed lower strength but superior ductility, with an elongation of 90.1± 3.6%. SEM fracture surface observations revealed typical ductile fracture features, including dimples and micro-voids, which corresponded well with the high elongation obtained from the tensile tests. X-ray diffraction analysis confirmed that the LFP-fabricated 316L stainless steel was mainly composed of the FCC γ-austenite phase, with no obvious BCC ferrite peaks observed. EBSD results further revealed anisotropic grain structures: fine and relatively uniform equiaxed grains were observed on the XY plane, whereas columnar grains aligned along the build direction were found on the YZ plane. The measured hardness of the printed specimens was 248.3 ± 6.0 HV in the horizontal direction and 228.3 ± 5.0 HV in the vertical direction, indicating stable mechanical performance.
For sensor integration, a slot measuring 14 × 19 × 0.36 mm³ was designed to match the geometry of the PVDF sensor. A segmented scanning strategy was adopted to reduce heat accumulation and minimize the risk of thermal damage during embedding. In conclusion, the results indicate that LFP is a promising approach for fabricating dense and ductile 316L stainless steel components and shows potential for the development of sensor-integrated smart metallic structures.

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