A computational approach to blanking processes

The present work presents a general framework for numerical simulation of blanking processes using finite elements. Blanking consists of a metal forming operation characterised by complete material separation. Experimental observations show that the shear process occurs in three stages: contact engaging, penetration/plastic deformation and rupture. In the first and second stages, large plastic deformation takes place, being primarily affected by punch displacement and clearance between punch and die. In the third stage, catastrophic failure occurs, leading to a complete material separation. A numerical approach to the problem requires a comprehensive finite element modelling due to the diversity of physical phenomena involved, such as large plastic deformation, material failure and coupled heat transfer. Furthermore, use of error estimation and re-meshing procedures is highly recommended due to element distortion, caused by lager deformation. This work discusses some of the issues involved in blanking modelling and analyses the influence of the clearance in stress distribution prior to material separation.