May 13 - 16, 2008
Gaylord Palms
Orlando, Florida USA

Extrusion/Die Theoretical

040TH  
Wednesday, May 14 - 3:15pm

Die Design and Manufacturability Formalization Using the Medial Axis Representation

Gijs van Ouwerkerk, Tom Vaneker, Fred van Houten -- University of Twente, The Netherlands;
Kjell Nilsen and Peter Koenis -- BOAL Aluminium, The Netherlands

With the focus on the production of more specialized products in smaller batches, aluminum extruders in Western Europe currently face increasing energy prices. This means that the financial and operational penalty of scrap production is becoming more important. The die is the key to reducing scrap. Its design and production should be optimized to increase the quality and stability of the extrusion process. A uniform exit velocity of the aluminum is the most important factor for achieving scrap reduction.

In this paper the development and implementation of a new design approach for the bearing areas of extrusion dies is discussed. The presented method links the important design parameters to the exit velocity of the aluminum. The exit velocity is calculated on the medial axis, a skeletal representation of the die cavity. Based on this calculation all design decisions and modifications can be quantified. This includes the use of a sink-in with a variable offset, variable bearing lengths, manufacturability optimizations and compensation for the effects of die deflection.