Shape Complexity in Metal Extrusion: Definitions, Classification, and Applications

One of the most important factors that affect quality and productivity in metal extrusion is shape complexity. It is an estimation of how complex an extruded profile (or die cavity) is. It has direct bearing on equipment selection, metal flow, die and tooling design, and critical process parameters. In turn, profile complexity has major impact on die life, energy consumption, cost of manufacturing, material properties, etc. Without proper quantification of shape complexity, it is difficult to predict maximum extrusion pressure needed or to optimize die/tooling or process parameters for improved process efficiency and product quality. The first part of the current paper presents a general classification scheme for extrusion profiles and covers the different definitions and their origins. The later part discusses some applications of shape complexity, such as pressure prediction; evaluation of stress, strain etc.; die design and optimization; product defects; prediction of container and exit temperature; friction and wear in complex dies; failure and life estimation of dies and tools; estimation of manufacturability and cost; and novel extrusion methods for complex profiles. The review concludes by pointing out areas where possible future research can be done. As no comprehensive review of this very important issue is available in the published literature, this paper can be very useful for researchers, academicians, and practitioners in the area of metal extrusion.