Finite element simulation for die-cavity compensation

A die-cavity will deflect elastically under the forming pressures, so that the design of the dies for “nett-forming” to eliminate subsequent machining has to taken into account the elastic behaviour of the die and the work material during the forging cycle. With a view to determining the die-cavity compensation requirements to negate the component-form errors resulting from the deflection of the die-cavity and the “springback” of the component, an approach of two-step decoupled FE simulation which uses separated models to predict the component-form errors is presented as an alternative to the coupled die/component modelling approach which regards both the die and the workpiece as deformable bodies in contact with each other. This is demonstrated with two specific components, one being a VTR flywheel and the other a forward extrusion rod, that the simplified approach is sufficiently accurate compared with the comprehensive modelling, in which the die and the component are simultaneously considered as deformable bodies in contact, and greatly reduces the cost of the analysis.