Die shape optimisation in forging of aerofoil sections

Dimensional tolerances are among the most important manufacturing criteria in the forging of aerofoil blades for aeroengine applications. A die shape optimisation system under development for the net-shape forging of aerofoil blades is outlined in this paper. In forging simulation using finite elements (FEs), a compensation approach was used in order to eliminate the aerofoil thickness errors due to die-elasticity. The optimised die shape is obtained by modifying the nominal die shape with a fraction of the die-elastic deflections through an introduced weighting factor. While forging simulation enables the evaluation of material flow, mechanical behaviour and die deflections, the compensation approach provides an effective means to minimise aerofoil thickness errors with only a small number of forging simulation iterations, suggesting substantial computing cost savings.