PARAMETRIC OPTIMIZATION OF POWER IN HYDROSTATIC EXTRUSION

The process of hydrostatic extrusion has gained great popularity in re cent years because of its simplicity and low cost. The material to be extruded is in contact with the die only, whilst in conventional extru sion the material is in contact with three components, the ram, the ch amber, and the die. Therefore, the power required to extrude the produ ct is less in hydrostatic extrusion. Added to this, the frictional los ses are kept to a minimum because of the hydrodynamic lubrication that takes effect at relatively high extrusion speeds, which prevents the product from coming into contact with the die. In this study, an analy tical model for studying hydrostatic extrusion is introduced. The mode l is used to investigate various parameters affecting extrusion, these parameters being: the die cone angle, the reduction ratio (the ratio of the billet diameter to the product diameter), the friction coeffici ent, the extrusion and back-pressure ratio, and the die shape. The mod el is extended to optimize the aforementioned parameters for securing a better product, and effecting minimum power requirement and small fr ictional losses. In order for it to gain recognition, the model was su bstantiated experimentally employing three commonly used engineering m aterials, the analytical and the experimental results being found to b e in good agreement. (C) 1997 Elsevier Science S.A.