Investigation on friction characteristics of micro double cup extrusion assisted by different ultrasonic vibration modes

Ultrasonic-assisted plastic micro-forming is a research hotspot in metal-forming process. The friction characteristic key factor affecting the properties of metal ultrasonic-assisted However, existed researches were mostly focused on characteristics free surfaces, while few studied between sample and mold cavity. In this paper, micro double cup extrusion experiments copper T2 conducted to investigate cavity with multiple ultrasonic vibration modes. Furthermore, numerical model was developed quantify stress reduction caused by modes estimate its contribution decreasing forming stress, which usually considered mainly affected acoustic softening, superposition, reduction. results show that surface roughness extruded samples are decreased sequentially tool (TV), workpiece (WV), compound (CV). height ratios also increased But increase ratio does not indicate coefficient. TV, CV, WV modes, 48%, 15%, 49%, respectively.