A COMPREHENSIVE REVIEW OF SCANNING PATTERNS IN DIRECT LASER METAL DEPOSITION FOR OPTIMIZING PROCESS AND PART QUALITY

Directed Energy Deposition (DED) has emerged as a transformative technology in additive manufacturing, enabling the efficient repair of high-cost metal parts and the creation of complex, customized components. This paper critically reviews the influence of scanning patterns in powder-based laser DED on part quality, focusing on how different patterns develop common defects such as cracks, porosity, distortion, and residual stresses. By synthesizing past research, this review reveals the impact of scanning patterns on key factors, including surface texture, substrate deformation, microstructure, and the anisotropy of mechanical properties. A comparative analysis of different shaped scanning paths highlights their respective advantages and limitations in achieving optimal part performance. While established patterns like raster and S-shaped paths show promising improvements in dimensional accuracy and surface finish, issues such as poor fusion, porosity, and uneven heat distribution persist. The review concludes that while carefully applying current scanning patterns can enhance part quality, further optimization is essential to reduce defects and improve fusion and residual stress management. Future research should focus on refining conventional scanning patterns or the development and application of innovative deposition patterns to maximize the potential of laser-based DED.