## 7 Conclusions  
This study investigates the implications of employing directed energy deposition (DED) processes for repairing forging tools and moulds. The comparison between specimens fabricated through conventional sheet metal and those formed via DED processes was conducted to establish the superior mechanical properties offered by the latter. This experimental study of the mechanical properties of materials manufactured by subtractive and hybrid processes yielded crucial insights. Subtractive processes, exemplified by laser-cut stainless steel, exhibited higher elongation at lower stress levels, indicating a more ductile nature under tension. Conversely, specimens produced via the DED process displayed a distinct pattern, showing higher stress and lower strain, highly influenced by the layer level of the DED deposition.  
The scatter plot's observed trends in stress and % strain highlight distinct mechanical properties between subtractive and hybrid manufacturing specimens. The DED process showcased layer-dependent behaviours associated with different deposition levels. While the highest level (DED L1) demonstrated lower tensile strength but higher elongation, indicative of enhanced ductility, the initial level (DED L3) displayed the highest tensile strength but exhibited a more brittle nature. Notably, the middle layers (DED L2), enduring the most prolonged exposure to heat, demonstrated median tensile strength but relatively lower elongation, indicating a brittle behaviour influenced by prolonged heat retention.  
This analysis highlights the crucial influence of DED's layering levels on resultant material properties, emphasising the compromise between strength and ductility.  
In the context of repairing metal forging tools and moulds, the hybrid repair approach, merging DED and CNC machining, served as a reliable solution for severe damage. This method not only restored critical components for mass production and high-stress applications, but also ensured precision and reliability, outperforming conventional repair methods.  
However, encountered issues during the repair process highlighted the significance of meticulous parameter control in the DED process. Factors such as initial laser power, layer dimensions, and material compatibility played pivotal roles. Deviations from optimal parameters often led to crack formations post-cooling, emphasising the criticality of adhering to manufacturer specifications for successful material deposition.  
Ultimately, this study underscores the potential of hybrid repair methods in repairing damaged forging tools and moulds for extended operational lifespans. However, a comprehensive understanding of deposition parameters remains essential in justifying post-process issues and ensuring the optimal performance of repaired components.  
Conceptualisation, R.E.P.; methodology, R.E.P.; investigation, M.-C.L.; resources, M.-C.L.; writing--original draft preparation, R.E.P. and M.-C.L.; writing--review and editing, R.E.P. and M.-C.L.; funding acquisition, R.E.P. All authors have read and agreed to the published version of the manuscript.  
This research was funded by Lucian Blaga University of Sibiu through the research grant LBUS-IRG-2022-08.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to restrictions.  
We acknowledge the support given by Compa SA company and Eng. [PERSON], Eng. [PERSON], and Eng. [PERSON], which contributed to the specimen fabrication and mould and tool repair process.  
The authors declare no conflict of interest.