Layer interface effects on dielectric breakdown strength of 3D printed rubber insulator using stereolithography

Abstract

The use of 3D printing technology enables the fabrication of optimally shaped and functionally graded structured high-voltage solid insulators that could be used efficiently in power grids owing to their compact size and reliability. However, understanding the layer interface effect is challenging. Therefore, we investigated the layer interface effect on the dielectric breakdown strength of 3D printed rubber insulators. We fabricated acrylic rubber insulators in different laminate directions using a stereolithographic 3D printer. The breakdown test revealed that a layer interface with a 0.1 mm laminating pitch reduced the AC breakdown strength of the insulators. Further, we evaluated the morphology of the layer interface and the surrounding hardness using microscopic and nanoindentation analyses. We found no delamination or voids around the layer interface. However, differences in hardness between the layer interface and the other part were observed. Therefore, it was concluded that owing to insufficient curing around the layer interfaces, the difference in the material structure promoted dielectric breakdown. Consequently, to minimize the layer interface effect on the breakdown strength, we proposed a thinner layer and 3D cylindrical printings.