## 1 Introduction
It is therefore necessary to adopt personal protective equipment, such as masks and respirators, gloves, goggles, and coveralls, in addition to exhaust systems and mechanical ventilation of working environments. Such devices are also important to protect against typical air emissions of fine powders from the material being sintered, as well as gases and volatile organic compounds released during polymer melting [26]. In addition, at the environmental level, the risk to aquatic and terrestrial systems is minimal for the disposal of natural graphite powder, while severe risks are associated with improper disposal of PA12 powders, which are highly recyclable [27] but not subject to natural degradation in soils, sewers, and waterways. Although several mechanical, chemical, or thermochemical recycling processes are already available for composite materials [28], research and development in materials science will be critically important to further improve their end-of-life management, increase their recyclability, and safeguard the planet's resources [29]. One of the major challenges in the fabrication of nano-graphite-reinforced polyamide composites using laser sintering is achieving uniform dispersion and strong interfacial bonding between the polymer and the nanofiller [18]. Proper dispersion of nano-graphite is crucial to prevent agglomeration, which could compromise the overall performance of the composite. Additionally, optimizing the laser processing parameters, such as laser power,scanning speed, and energy density, is essential to ensure efficient sintering, minimize porosity, and achieve desirable mechanical and thermo-electrical properties [30]. To date, several studies have been conducted to investigate the effect of raw material nature (i.e., type, geometry, supplier, etc. ), filler nature and concentration, process parameters, laser sintering equipment, and post-processing operations on the resulting flowability, processability, and electrical and mechanical properties. [PERSON] et al. [31] determined the effect of a processing method on the mechanical, thermo-mechanical, and electrical properties of graphite nanoplatelet-reinforced PA12 composites, demonstrating improved tensile, flexural, impact, and electrical properties compared to a sample fabricated through the traditional injection molding technique. However, for weight percentages greater than 5%, the property enhancement was compromised due to the filler agglomeration. [PERSON] et al. [32] prepared high-performance composites based on a thermoplastic polyamide matrix containing well-dispersed graphene nanoplatelets through melt compounding, improving the electrical, thermal, and mechanical properties at a filler volume fraction of around 15%. [PERSON] et al. [33] developed electrically conductive polymer composites made of PA12 reinforced with carbon fibers and graphite, mechanically mixing the raw materials in different relative amounts. They verified that the hybrid composites allow great enhancements in electrical conductivity with respect to the neat PA12 up to the anti-static and conductive range, while no synergistic effect between the two fillers was observed. [PERSON] et al. [22] fabricated nanocomposite powders based on a core-shell structure, where graphene nanoplatelets were encapsulated on the surface of polymeric particles of PA12 in a thin layer of polyvinyl alcohol (PVA). They showed that the presence of the PVA and the nanofiller accelerated the crystallization of the nanocomposite powders compared to plain PA12, impacting the laser sintering process parameters, leading to modest improvements in the mechanical properties. From the literature, it emerges that numerous combinations of PA powders with different fillers, mixing methods, and fabrication parameters are currently being studied to identify the optimal components that meet the stringent requirements of modern industry.