###### Abstract  
This article investigates the efficacy of directed energy deposition (DED) processes in repairing forging forging tools and moulds, comparing mechanical properties between specimens fabricated from conventional sheet metal and those manufactured by DED techniques. A comparative analysis reveals significant mechanical differences between subtractive and DED-manufactured specimens, emphasising the nuanced balance between tensile strength and ductility in DED-produced components influenced by layering. Notable insights from scatter plot analyses highlight distinct material behaviours, particularly layer-dependent tendencies in DED-manufactured specimens. Regression-based predictive models aid in understanding material behaviours, aiding in informed material selection for manufacturing processes. Additionally, this article underlines the advantages of DED-based repair processes, highlighting precision, material efficiency, reduced lead times, and cost-effectiveness. The article studies die and mould repair, tool restoration, and critical considerations like material compatibility and quality assurance. The study concludes by emphasising the role of hybrid manufacturing in extending product lifecycles, in conformity with specific mechanical requirements, and fabricating complex geometries, despite potential higher costs in materials and technologies. Overall, this research demonstrates the efficacy of DED processes in enhancing component reliability and lifespan in metalworking industries.  
hybrid manufacturing; directed energy deposition; additive manufacturing; forging tools +
Footnote †: journal: _Applied Sciences_  
The main advantage in using hybrid technologies is that the freedom of the geometric configuration of components is much greater due to the possibility of configuration oriented exclusively to its functional requirements [3]. Thanks to this, the number of parts required for the construction of an assembly can be reduced. Another advantage is that lightweight aeronautical and aerospace construction concepts can be executed on bionic principles, which cannot be realised in practice using conventional manufacturing processes.  
Although additive manufacturing processes can generate shapes with geometries very close to the final geometry of the final components, they cannot meet the quality and precision requirements of functional parts; therefore, a conventional manufacturing process such as milling is needed to further refine the shape. Additionally, the components require support structures to prevent deformations during the 3D deposition process, which are based on the Design for Additive Manufacturing (DfAM) principles and the geometry of the components [4]. These support structures also must be removed after the 3D deposition process, which can only be done with conventional technologies [1].  
Since the geometry generated by the additive manufacturing process is much closer to the final geometry of the finished component, conventional manufacturing processes will remove much less material due to minimal machining additions, resulting in a much more efficient use of materials, unlike using only subtractive manufacturing processes [5].  
In the case of a CNC equipment used for hybrid manufacturing processes, it shall be capable of performing additive and subtractive processes in a combined manner without the need for further handling of the components in processing. For the DED hybrid manufacturing process, it can mix the additive and subtractive processes in a single manufacturing operation, which can save materials and time. However, the manufacturing technology needs to be carefully designed and verified to avoid errors and collisions. For example, during the milling process, if the cutting tool goes over an area more than once, it does not cause problems, but in the additive process, if the deposition head follows the same tool path over the same surface after a layer has been applied, there will be a collision between the tool and the part.