Dielectric Properties of 3D Printed Insulators with Microfillers for High-Voltage Applications

3D printing has emerged as one of the most swiftly advancing methods for object manufacturing in recent times. Within various 3D printing technologies, stereolithography (SLA) is the most suitable for fabrication of high-voltage (HV) components. In SLA, UV light is utilized to cure liquid resin. To alter the dielectric characteristics of 3D printed HV components for field grading purposes, specifically the parameters of permittivity εr and conductivity σ , fillers can be incorporated in the liquid resin. This contribution focuses on investigating the applicability of barium titanate (BaTiO 3 ) and biochar as fillers for UV-curable resin. To find the required printing parameters, disc samples with varying filler contents were fabricated in a commercial SLA printer. To investigate the influence of the two filler materials on the dielectric properties of SLA resin, the characteristics of the printed samples most relevant for HV applications (permittivity εr , dissipation factor tan δ , and conductivity σ) were determined. Ultimately, maximum filler contents of up to 40 wt% of BaTiO 3 and 4 wt% of biochar were implemented successfully. In general, adding a filler was always observed to increase permittivity εr as well as conductivity σ . The measurements showed that the maximum achievable filler content of 40 wt% BaTiO 3 increases permittivity εr by 30% and conductivity σ by a factor of 2.27, compared to neat resin. Similarly, for 4 wt% biochar, permittivity εr and conductivity σ increased by 70% and a factor of 52, respectively. The performed laboratory experiments demonstrated how HV components could be manufactured with SLA 3D printing processes in the future. With the established influence of various contents of microfillers on the dielectric properties of SLA resin, material properties can be optimized for specific applications. In combination with rapid SLA printing processes, these “tailor-made materials” can be used to manufacture complex HV components.