## 5 Discussion
### Layering Strategy
\begin{table}
\begin{tabular}{c c} \hline \hline
**Strengths** & **Weaknesses** \\ \hline Precision repair: DED allows for precise material deposition, enabling targeted repairs on damaged areas with minimal material wastage. It offers high accuracy in restoring complex geometries. Material efficiency: by adding material only where needed, DED reduces material waste compared to traditional methods that may involve machining away substantial volumes. & Surface finish: post-processing machining is often necessary to achieve the desired surface finish and required tolerances, adding time and cost to the process. Complexity: optimising parameters for DED requires expertise and iterative adjustments, making it complex for inexperienced operators. Quality assurance: ensuring uniform material properties across the repaired area might be challenging due to factors like inter-layer adhesion and microstructural variations. Material compatibility: limited material compatibility might be a constraint, particularly when repairing diverse materials or for specific industrial applications. \\ Cost-effectiveness: while initial setup costs might be high, DED can be more cost-effective for intricate repairs or producing low-volume, high-value components compared to traditional methods that involve extensive machining and reworking. & Post-repair inspection: verifying the integrity and quality of the repaired parts might be more complicated compared to conventional repairs due to the layering nature of DED. \\ \hline \hline \end{tabular}
\begin{tabular}{c c} \hline \hline
**Strengths** & **Weaknesses** \\ \hline Established techniques: techniques like welding, milling, and manual machining are well established, making them easier to adopt and execute. Surface finish: conventional methods often provide superior surface finishes directly after repair, reducing or eliminating the need for extensive post-processing. Material familiarity: technicians are often experienced in traditional repair methods, facilitating easier implementation without the need for specialised training. & Material removal: conventional methods might involve substantial material removal, leading to material wastage and potentially weakening the repaired component. Limited precision: achieving precision in complex repairs might be challenging, especially for intricate geometries or hard-to-reach areas. Extended lead times: time-consuming setup and machining processes might result in longer lead times for repair and component replacement, impacting operational timelines. Cost inefficiency: material wastage and the need for extensive machining can make conventional repair methods more costly, especially for complex repairs or low-volume production. \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparative analysis between conventional repair and DED-based repair methods. cooling rates could allow for a more uniform microstructure and better ductility but might negatively impact strength. This behaviour was notably observed in parts manufactured during different ambient temperature conditions--during winter, characterised by lower ambient temperatures in the vicinity of the DED hybrid manufacturing machine, micro fissures were observed in the repaired sections of parts. In contrast, during summer, when the ambient temperature significantly rose, micro fissures were absent in the DED-repaired parts. However, the increased humidity levels during summer led to a quicker onset of rusting for the DED-refurbished parts. Adequate bonding between layers is also critical. Incomplete fusion or poor bonding can create discontinuities, reducing overall strength. Optimising parameters like laser power, deposition speed, and overlap between successive layers can enhance interlayer bonding, influencing both tensile strength and ductility. Layering also influences the grain orientation and growth. A uniform, fine-grained microstructure generally improves mechanical properties.