OPTIMIZATION OF SPECIFIC DIE PROFILES IN THIN WALLED TUBE EXTRUSION

In the present work, three extrusion profiles have been investigated objectively, these are a conical, a cosine which is proposed in this study and a profile designed to impose equal strain increments over the equi-spaced sections. Each of them reduces a portion of the required power for extrusion. Conical profile provides the least frictional surface, cosine profile omits the surfaces of velocity discontinuity and the other profile reduces the power attributed to redundancy during deformation. However, the capability of these profiles in reducing the total power of the process is very different. Results suggest that cosine profile is the best energy-wise, whereas the profile which imposes equal strain increments over the equi-spaced sections provides the best distribution of strain in the product. In addition, a simple exponential equation as a function of die geometry is presented for the case of the profile which imposes equal strain increments over the equi-spaced sections.