**In Memoriam**

We want this Special Issue to serve as a posthumous tribute to our colleague and friend Mariano Marcos Bárcena, who participated very actively in the genesis of this thrilling project, and whose contribution to manufacturing engineering is present in this Special Issue, both explicitly, in a concrete work, and implicitly, in several papers by his research group from the University of Cadiz who have kept working on the investigation lines promoted by him.

**Conflicts of Interest:** The authors declare no conflict of interest.
