Three-dimensional analysis of residual stress in EDM

The quality assurance is a important subject in Electrical Discharge Machining Especially, the stress generated on machined surface is a cause of generating of crack and residual stress, The residual stress causes decrease of fatigue strength, delayed fracture and stress corrosion which affed life and quality of the workpiece and damage reliability of the product.In this report, according to thermal elastic/plastic theory in which the hysteresis of thermal stresses and strains accompanying distribution of temperature are calculated in order, the analysis on thermal stresses and residual stresses are developed in form of three dimensions of symmetrical axis by means of finite element method, in which the workpiece material's physical properties dependent on temperature are taken into consideration.The problems about generation of stress in Electrical Discharge Machining are made more clear by this method then the analysis of two dimensions in the past by means of elastic theory in which the plastic strains are not taken into consideration.