ICEB 2009 Dortmund: International Conference on Extrusion and 3rd Extrusion Benchmark

In the 2009 Benchmark, a multiple hole die for the simultaneous extrusion of two U shape profiles was designed (Figure 2, left) in order to produce an effective comparison for different tongue design strategies. The bottom profile was characterized by a standard supporting shape while the supporting part of the upper profile was deeply shortened (26.95 mm) in order to achieve a measurable die deflection during the process (Figure 2, right). With this configuration, a higher deflection of the upper part of the die with the less supported inner profile contour was expected, producing a loss of contact in the bearing zones and an alteration of the thermal field at the two exits and as a consequence a difference also in material flow and profile distortions was expected for the two profiles. On the other hand, the U-shape of the profiles allows the accessibility for laser measuring devices to detect the deflection of the inner tongues along the extrusion direction, while the length of the U-shape (59.3 mm) provided for an adequate magnification of the die deflection. The die was made of AISI H-13 hot-working tool steel tempered to 45 HRC hardness and built by WEFA, Germany.