Brittle–ductile transition model for ultrasonic vibration–assisted blade dicing

Abstract

The critical machining parameters of the brittle–ductile transition (BDT) play a crucial role in enabling ductile-mode machining of brittle materials. Ultrasonic vibration–assisted blade dicing (UVABD) enhances machining quality significantly compared to conventional dicing methods. Nevertheless, radial ultrasonic vibration complicates the motion trajectories of the irregular grains on the dicing saw, making it difficult to predict the critical machining parameters. A comprehensive model that can predict critical machining parameters for BDT in UVABD has yet to be developed. In this paper, a mathematical model is proposed to predict the critical machining parameters for BDT in UVABD, considering the actual grain geometric characteristics and the interactions among multiple grains affected by ultrasonic vibration. The model was validated through experiments on single-crystal silicon wafers. A combined numerical and experimental method was used to comprehensively investigate the critical machining parameters for BDT. The results indicate that material removal in UVABD primarily involves plastic ploughing and brittle fracture. The proposed model's predictions agreed well with the experimental results, with the average relative error being 10.7 %. Finally, the model was applied to examine how machining parameters influence the critical machining parameters for BDT. Higher spindle speeds and vibration amplitudes, combined with lower feed rates and dicing depths, were found to facilitate the realization of ductile machining. This study establishes a theoretical foundation for ductile machining in UVABD and offers new insights into the BDT mechanism of brittle materials under UVABD.