## 1 Introduction  
In recent years, the demand for advanced materials with enhanced mechanical, electrical, and thermal properties has significantly increased, driven by the rapid evolution of industries such as aerospace and automotive [1], healthcare [2], and consumer electronics sectors [3]. Among the many technological innovations, additive manufacturing (AM) has emerged as a key enabler of next-generation material design, allowing the fabrication of complex structures with tailored functionalities [4, 5]. One of the most promising AM techniques is laser-based powder bed fusion, defined as laser sintering, according to the ASTM 52900 standard [6], which enables the production of high-performance polymer composites with complete freedom from geometrical constraints compared to traditional manufacturing methods [7]. However, such polymer processing technology still suffers from some limitations [8], mainly related to long process times, low surface quality, reduced print resolution, anisotropy, and the presence of porosity, which still pose a challenge for mass production [9], as well as for its effective scalability from the laboratory to the industrial level. Future technological advances will therefore be of paramount importance to achieve rapid, large-scale printing of reliable, high-performance products, while maintaining a high level of customization [10]. Within this context, polymer composites reinforced with nano-graphite have gained interest due to their unique multifunctional characteristics [11]. Nano-graphite is known for its exceptional electrical conductivity and thermal stability [12] and mechanical strength [13], while maintaining a low production cost compared to other carbon nanoscale materials, such as graphene nanoplatelets and nanotubes [14; 15], making it an ideal candidate for enhancing polymer matrices [16]. Smart materials are broadly defined as systems capable of responding to external stimuli, such as mechanical stress, electrical signals, or temperature changes, and often integrate sensing, actuation, or conductivity functions [17]. By incorporating nano-graphite into polyamide (PA) powders, it is possible to develop composite materials with improved thermal conductivity and electrical properties, opening the door to a wide range of smart applications [18]. Among polyamides, grade 12 (PA12), also known as nylon-12, is widely used in laser sintering processes due to its excellent processability, chemical resistance, and durability [19]. However, conventional PA-based materials often exhibit limitations in electrical and thermal conductivity, restricting their use in applications requiring functional integration, such as sensors, lightweight conductive components, and electromagnetic shielding [20]. In fact, electrically conductive polymer composites are considered smart materials that are able to combine insulating polymers and carbon-based nanof fillers and are frequently adopted in applications such as structural health monitoring, wearable electronics, and electromagnetic shielding [20; 21]. The introduction of nano-graphite reinforcement can effectively address the abovementioned limitations, enhancing a material's conductive pathways while maintaining the structural integrity and flexibility of the polymer matrix [22]. However, regarding safety, handling fine powders poses a risk of inhalation, ingestion, and contact with skin and eyes, as well as a risk of forming explosive mixtures with air. The greatest risks are related to inhalation toxicity [23], with the possibility of the development of respiratory and cardio-vascular disorders, but also pulmonary diseases [24], such as graphite pneumoconjugis, asthma, and lung cancer. A recent study in Malaysia has verified that during the printing preparation stage of PA12 in laser sintering processes, particulates with a diameter lower than 2.5 \(\upmu\)m (i.e., PM 2.5) and CO\({}_{2}\) exceed the acceptable limits recommended [25].