## 1 Introduction
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline
**Technique** & **Energy Source** & \multicolumn{2}{c}{**Advantages**} & \multicolumn{2}{c}{**Disadvantages**} & \multicolumn{2}{c}{**Industrial Usage**} \\ \hline \multirow{9}{*}{(Laser Metal Deposition) LMD} & \multirow{4}{*}{\(\bullet\) high-power laser beam} & \(\bullet\) & High deposition rate [16] & \(\bullet\) & Residual stress & \(\bullet\) & Repair and re-manufacturing \\  & & & Control and precision [17] & \(\bullet\) & Complexity of process parameters & \(\bullet\) & Surface treatment \\  & & & Precision [17] & & control & & and coating [22] \\  & & & Wide range of material usage & \(\bullet\) & High equipment & \(\bullet\) & Prototyping and rapid tooing \\  & & & Low waste and high efficiency [18] & \(\bullet\) & Low surface finish & \(\bullet\) & Aerospace and aviation [23] \\  & & & Strong metallurgical & \(\bullet\) & Requirement [18; 19] & \(\bullet\) & Medical devices \\  & & & bonding [17] & \(\bullet\) & Safety & \(\bullet\) & Tool and mold \\  & & & Design flexibility [17] & & considerations & \(\bullet\) & Manufacturing \\ \cline{2-6}  & & & High energy & & & & \\  & & & density [24] & & & & \\  & & & Excellent material & \(\bullet\) & Preheating & \(\bullet\) & Oil and gas \\  & & & & Accurate control of heat & & requirements [25] & \(\bullet\) & Power generation \\ (Electron beam directed energy beam & Electron beam & \(\bullet\) & Input input & \(\bullet\) & Limited build & \(\bullet\) & Defense and military \\  & & & Smaller heat & \(\bullet\) & volume [26] & \(\bullet\) & medical devices \\  & & & affected zone & \(\bullet\) & High equipment & \(\bullet\) & Automobile \\  & & & Large scale & \(\bullet\) & cost [27] & & industries \\  & & & manufacturing & \(\bullet\) & Safety & \(\bullet\) & Repair and \\  & & & High material efficiency & & consideration [25] & & re-manufacturing \\  & & & & Capability of using & & & [30; 31; 32] \\  & & & different materials [25] & & & & \\ \cline{2-6}  & & & & & & & \\ \cline{2-6}  & & & High deposition rate [33] & \(\bullet\) & Low surface quality [36] & \(\bullet\) & Maritime and \\  & & & & Cost-effective & \(\bullet\) & Quality [36] & \(\bullet\) & Aerospace [39] \\ (Wire and Arc Additive Manufacturing) & & & Material compatibility & \(\bullet\) & Limited resolution & \(\bullet\) & Railways \\  & & & Material and variety [34] & \(\bullet\) & Overhang and & \(\bullet\) & Heavy machinery \\  & & & Large-scale printing [35] & \(\bullet\) & Support structures & & and construction \\  & & & & Large-scale printing [35] & \(\bullet\) & Distortion and & \(\bullet\) & Oil and gas [39] \\  & & & Reduced tooling & \(\bullet\) & residual stresses & \(\bullet\) & Power generation \\  & & & requirements [25] & \(\bullet\) & Post-processing & \(\bullet\) & Defense and \\  & & & High speed of & requirements [37] & & military [41] \\  & & & printing [25] & \(\bullet\) & High-cost learning & \(\bullet\) & Repair and re-manufacturing [42] \\ \cline{2-6}  & & & & Different types of & \(\bullet\) & Post-processing & \(\bullet\) & Mining and construction \\  & & & material & requirements & \(\bullet\) & Aerospace \\  & & & & Freedom of design & \(\bullet\) & Soil and gas \\  & & & Enhanced material & \(\bullet\) & Post-processing & \(\bullet\) & Power generation \\  & & beam & properties & requirements & \(\bullet\) & Defense and military \\  & & & & Multi-material printing & \(\bullet\) & Safety & \(\bullet\) & Medical devices \\  & & & & & & \\  & & & & usage & & considerations & \(\bullet\) & Automobile \\ \cline{2-6}  & & & & & & \(\bullet\) & Low process speed \\  & & & & & Energy consumption & \(\bullet\) & Surface \\  & & & & consolidation [43; 44] & \(\bullet\) & Thermal & enhancement and \\  & & & & & distortion [46] & & coating \\  & & energy & \(\bullet\) & Material efficiency [45] & \(\bullet\) & Limited resolution & \(\bullet\) & Aerospace and \\  & & & & Multi-material & \(\bullet\) & Low surface quality & \\  & & & capability & \(\bullet\) & Complexity of & \(\bullet\) & Defense and military \\  & & & & & tool design & & \\ \hline \hline \end{tabular}
\end{table}