Parametric optimisation of power in hydrostatic extrusion

The process of hydrostatic extrusion has gained great publicity in recent years because of its simplicity and low cost. The material to be extruded is in contact with the die only. In conventional extrusion, the material is in contact with three components, mainly the ram, the chamber, and the die. Therefore, the power required to extrude the produce is less in hydrostatic extrusion. Add to this, the frictional losses are kept to a minimum because of hydrodynamic lubrication that takes place at relatively high extruding speeds. This will prevent the product from coming into contact with the die. In this study, an analytical model for studying hydrostatic extrusion is introduced. The model is used to investigate various parameters affecting extrusion. These parameters are mainly: die cone angle, sample reduction ratio (ratio of billet diameter to product diameter), friction coefficient, extrusion and back pressure ratio, and die shape. The model is extended to optimise the aforementioned parameters for better product, minimum power requirements and small frictional losses. To gain recognition, the model was substantiated experimentally using three commonly used engineering materials. The correlation between the analytical and experimental results are found to be in good agreement.