Performance and Mechanism on Sand Mold Ultrasonic Milling

Sand mold milling plays a critical role in digital mold-free casting, but it is prone to damage such as corner collapse, collapse, and cracks during the machining process. To address this issue, ultrasonic vibration was used for sand mold milling in this study. By incorporating the solid–liquid transition model for sand mold cutting and considering the deformation characteristics of the shear zone, a prediction model for ultrasonic milling forces in sand mold was developed and experimentally validated. The results demonstrate that increasing the spindle speed and decreasing the feed rate lead to a decrease in cutting force. At high speeds, there is a 15% error between the dynamic milling force model and experimental values. Compared with conventional processing methods, ultrasonic processing reduces cutting force by 19.5% at a frequency of 25.8 kHz and amplitude of 2.97 μm, minimizes defects like sand particle detachment pits on the surface of sand mold, significantly improves surface quality, and enables precise, stable, high-precision, and efficient sand mold processing.