Multi-material and parameter-controllable stereolithography 3D printing of graded permittivity composites for high voltage insulators

Graded permittivity materials have gained significant attention due to their exceptional ability to regulate electric fields. Multi-material stereolithography (SLA) 3D printing has opened up new possibilities for creating such materials. However, conventional SLA printers typically generate graded material using fixed printing parameters and multiple feedstocks with limited differences, resulting in a constrained capacity for modulating the electric field distribution. To address this limitation, we have developed a multi-material, parameter-controllable SLA strategy, enabling us to assign varying printing parameters for each building layer and switch between feedstocks with significant differences. Solid insulators with graded permittivity are optimised through electric field distribution simulations and subsequently manufactured using our innovative multi-material SLA approach. A 4-layered graded insulator effectively decreases the maximum electric field strength from 82.5-30.8 kV/mm. Both flashover tests and partial discharge signals confirm that graded insulators outperform homogeneous ones in electrical insulation.