Laser etching effect and enhanced chemical degradation of epoxy resin in dry-type transformer windings

Abstract Dry-type transformers are essential power equipment components. Traditional disposal methods for their windings, such as mechanical destruction, landfill, and incineration, face limitations in terms of environmental sustainability and degradation efficiency. In this study, cut blocks of dry-type transformer windings were subjected to laser etching using various laser parameters. The etched surface morphology and elemental composition of by-products were observed, and comparative experiments on chemical degradation were conducted before and after laser treatment. The results indicate that laser power and scanning speed had a significant impact on etching performance. The laser frequency reached its threshold at around 500 kHz. At the microscale, the etched surfaces exhibited porous structures, micro-cracks, and delamination of glass fibers. The by-products generated during etching presented as irregular crystals, with silicon as the dominant element and a small amount of carbon. Comparative chemical degradation tests revealed that the degradation rate of pretreated samples significantly increased. The core mechanism of laser etching of epoxy resin is thermal decomposition.