Eliminating Streaking Defects in Anodized Aluminum Extrusions for Auto Roof Racks

摘要

Due to increased demands for quality and the higher cost of extruded scrap in the present aluminum extrusion market, good extrusion process parameter control becomes more critical in optimized value-added processing in order to achieve excellence in aluminum extrusion practice. Billet recovery, elimination or reduction of extrusion surface defects, and overall scrap reduction, especially of scrap with value-added content, all add to total value in the extrusion process. This article describes common streaking problems in anodized aluminum extrusions and the influence of die deformation on extruded profile tolerances, and it teaches how to effectively improve tool stack design to minimize deflection and eliminate post-anodized streaking or post paint flow lines on 6063-T6 automotive roof rack extrusions.