Surface quality prediction in aluminum extrusion
conference paper
The surface quality of aluminium extrusion products can be hampered by undesired surface features like die lines and pickups. In particular the presence of pickups is considered as undesirable. Surface pickups appear as intermittent torn marks on the aluminium extrusion products, often terminated with a protruding lump rising above the surface up to hundreds of microns in height. Using a model calculating initiation, growth as well as detachment of the lumps on the die bearing surface, the surface quality of aluminium extrusion products can be predicted. The results of the model can be presented in terms of surface quality diagrams, where contour lines of the (normalized) calculated number of lumps are presented in terms of exit speed and extrudate surface temperature. These diagrams are unique for a certain combination of geometry of the extrudate and the aluminium alloy and can be used to optimise process conditions with respect to surface quality within a certain process window. In order to validate the model, the size and number of pickups on the surface of a labscale extruded strip of AA6063 have been measured. The results of the model are being compared to the experiments and show good agreement.
Topics
TNO Identifier
442924
ISSN
10139826
ISBN
9783037852507
Source title
2011 International Conference on Extrusion and Benchmark, ICEB 2011, 3-5 October 2011, Bologna, Italy
Collation
8 p.
Pages
27-34
Files
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