INFLUENCES OF CROSS-SECTIONAL GEOMETRY AND SURFACE ROUGHNESS ON THE COMPRESSION STABILITY IN UPSETTING HIGH ASPECT-RATIO SHAPED BILLETS BY FE ANALYSIS

摘要

Metal forming for micro or mini-parts is a new developing trend in the metal forming application. The analysis of billet compression stability in upsetting is essential in selecting forming parameters and determining the size effect. The current study aims to explore the influence of billet geometry and surface roughness on the compression stability in upsetting high aspect-ratio shaped billets. 3D finite element simulation was employed to analyze the influence of surface roughness on the end faces of the billet and shapes profiles of the billet cross-section, on buckling in upsetting mini-size billets. Simulation results indicated that the rougher the contact surface, the lower was compression stability in upsetting the billets. In addition, the cross-sectional shape of the billet affected the compression stability in upsetting. Mini billets with larger shape factors would lead to higher compression stability.