To Study the Influence of Frictional ...

Component errors and die deflection and hence the quality of the extruded components are directly influence by the generated temperature due to friction during the process, the elastic and plastic behavior of the component, die geometry and billet and die material. Finite element simulation is conducted to study the influence of Die Land Length (DLL) and frictional conditions between the die inner surface and billet outer surface, on the component errors and die deflection during forward extrusion by using elastic plastic considerations. The simulations show that the dimensions of the work-material and die are affected by increase in temperature due to the change in frictional condition during process and die-elasticity during both, loading and unloading of the die. Increasing the punch pressure and hence friction between the billet and die results in larger radial deflection of the die during extrusion (loading), which results in larger values of component errors in extruded material. The elastic contraction of the die during the punch retraction (unloading) reduces due to high level of friction and more amount of heat generated; hence larger form errors are sustained after unloading. The plastic deformation of the billet material remaining in the die is influenced by the temperature variation in the billet as well as in the die during unloading phase, this plastic deformation of the billet material due to the temperature variation has a significant role in the overall form error of the component, hence the quality of the extruded material. Although, the die land length does not have significant effect on bar temperature, die stress and die deflection but it has a significant effect on component error which reduces with increased die land length.