Parametric investigation on the curling phenomenon in CONFORM process by three-dimensional finite element analysis

Owing to the circular material flow, a CONFORM continuous extrusion forming process exhibits more complicated process characteristics compared to conventional front- and side-extrusion processes. One remarkable thing is the curling phenomenon in the material flow after it passes through the die, and which is caused solely by the non-uniformity in material velocity profile at the die section. Since this process has been introduced, this phenomenon has not been intensively studied, and furthermore most of analytical and numerical studies for the process have been carried out with the simplified two-dimensional plane-state model. Through the three-dimensional finite element analysis of CONFORM process, we in this paper address the parametric investigation on the curling phenomenon together with the more realistic understanding of the flow characteristics in the die region. For the parametric experiments, we take the wheel velocity, the abutment height and the flash gap size as considering parameters.