Three-dimensional finite element analysis of a flat die form rolling process

摘要

This paper investigates a cold forming process called Form Rolling. Form Rolling is an innovative method of producing near-net shape parts, which is of particular interest to fastener manufacturers. In this study, a three-dimensional finite element analysis (FEA) was used to simulate a flat die Form Rolling process that formed grooves of two different depths on a rolling workpiece. The FEA package used for this study was Deform3D, which is an elastoplastic, implicit Lagrangian adaptive remeshing finite element code that has the ability to characterise both the workpiece material stresses and deformation behaviour. The bulk material flow and stress state have a dramatic effect on the Form Rolling process. An understanding of the material flow is important when designing the tooling required to correctly form particular geometries, while a better understanding the stress state can help explain the occurrence of defects in the workpiece and in the Form Rolling tools. The flat-die form rolling process is similar to a thread rolling operation, in which a cylindrical workpiece is fed between two flat dies and the relative motion between the flat dies is used to produce the desired geometry. This technique has many advantages over machining, and these include producing stronger parts with better mechanical properties and with a substantial reduction in waste material (Johnson and Mamalis, 1977).