## 3 Results  
The experiment involved testing five conventional specimens and five hybrid stacks, each consisting of three specimens produced by DED processes. The DED specimens are further referred to with the following codes: DED Level 1 (DED L1), the specimen from the top level of the stack; DED Level 2 (DED L2), the specimen from the middle level of the stack; and DED Level 3 (DED L3), the specimen from the bottom level of the stack which is deposited on the S235 JR base plate. All specimens were subjected to tensile loading until they failed. The purpose of this experiment is to demonstrate that the parts made by DED methods have superior mechanical properties compared to the stainless steel used for making forging tools and moulds. Figure 8: Orientation device (**a**) and attachment of a specimen to the testing machine (**b**). Figure 7: Nozzle damage due to excessive laser power and residual material splashes. Since the test values of each specimen set are consistent (Figure 9) with their counterparts, no outliers were identified among the specimens. Therefore, to highlight the differences between the types of specimens, the mean value for each set of specimens was calculated and compared. The scatter plot (Figure 10) showcases a comparative view of stress in [MPa] against the percentage of elongation for each specimen group's mean value. Elongation (%) or reduction in area (%) represents the tensile ductility. The equation of determining elongation (%) was calculated by the testing machine using Equation (1), where L0 is the initial length of the sample and \(\Delta\)L is the difference between the initial length and the elongated final length. \[\text{ Elongation }(\%)=\frac{\Delta\text{L}}{\text{L}_{0}}\times 100\% \tag{1}\]  
This graphical representation provides valuable insights into the material behaviour under tension for both subtractive and hybrid manufacturing methods. Subtractive (laser-cut stainless steel) specimens exhibit a higher elongation at lower stress levels, suggesting a more ductile behaviour in response to tension. In contrast, specimens produced through the DED process exhibit a notably different pattern on the scatter plot. They portray a higher stress and lower elongation tendency, particularly influenced by the layer level of the DED deposition. The specimens produced through the DED process demonstrate a behaviour linked to the layer level of deposition. The highest level (DED L1) exhibits the lowest tensile strength, indicating decreased strength, but the highest elongation percentage, indicative of a more ductile behaviour. The initial DED level (DED L3) displays the highest tensile strength but also a more brittle nature. The middle specimens (DED L2) exhibit a moderate tensile strength compared to the initial and final specimens but show a reduced elongation. This behaviour leans towards brittleness, likely attributed to the middle layers retaining heat for an extended duration during the deposition process. Heat dissipation dynamics differ for these layers, with the base level dissipating heat into the metal base plate and the final level dissipating heat into the atmosphere. Figure 10: Stress–strain curve for the mean values of each specimen set. Using Minitab 20 software, a regression analysis (Figure 11) conducted for each specimen group's stress and % elongation scatter plot enabled the creation of prediction plots, offering an empirical representation of the material behaviours under tension. The prediction plots contain the stress-strain curve for the mean of each specimen group, visually presenting the relationship between stress and % elongation. The red line within each prediction plot represents the predicted X and Y values, offering a trend line that highlights the anticipated material behaviour based on the regression analysis. An essential aspect of these plots is the inclusion of a 95% prediction interval. This interval denotes a range within which 95% of the observed data points are expected to fall, illustrating the uncertainty associated with the predictions.