Laser-induced selective metallization of epoxy resin: Preparing ultra-thin and ultra-light motors

Abstract

Epoxy composites with an excellent laser-induced selective metallization (LISM) capability were designed and prepared by combining the bisphenol A-type epoxy resin (EP) with laser sensitizers (CuO·Cr2O3 and ATO). The dispersion of laser sensitizers in epoxy molding compound (EMC), as well as their influence on the curing reaction and mechanical strength of epoxy composites, was investigated. We confirmed that CuO·Cr2O3 is the more suitable laser sensitizer for epoxy composites. The tensile strength of EP/CuO·Cr2O3 composite was 51.6 MPa, and the resistance of the obtained copper layers was 0.2 Ω. Moreover, this composite can be used to produce ultrafine copper wires and perforated circuits using LISM technology. Inspired by its excellent LISM performance, an ultra-thin and ultra-light motor was designed and fabricated. The weight of the entire motor was only 28.8 g and a thickness of 6 mm due to the integration of the stator frame and stator windings.