Influence of filler diameter on UV transmission and dielectric permittivity of alumina composite used for stereolithographic 3D printing

We investigated the feasibility of 3D printing of an insulating component using polymer composites. In the stereolithographic 3D printing by using a UV-cured resin composite with micrometric alumina fillers (alumina composite), the scattering and absorption of UV light by alumina fillers are a potential obstacle to UV curing. This paper investigated the influence of filler diameter on UV transmission and dielectric permittivity of alumina composite. The UV transmittance of alumina composites increased with the increase of the average filler diameter from 6 μm to 15 μm. The permittivity of the alumina composites did not depend on the filler-diameter. Finally, we confirmed that the alumina fillers with the average diameter of 6 μm and 15 μm were not obstacle to UV curing. The suitable filler-diameter of alumina composites for the stereolithographic 3D printing was discussed.