 | 2008 |
Abstract:
In an attempt to increase the energy efficiency of vehicles, lightweight and thin construction elements are designed, keeping in mind that the safety of the passengers should not be decreased. Controversial specifications lead to the research and development of new materials. Composite extrusions with aluminum-matrix combine the high ductility of the matrix-material with the strength of continuous reinforcing-elements. Today, it is possible to specific reinforce profiles by an extended extrusion process. It allows producing light framework structures with an excellent resistance against defined outer loads. The contrast of ductile matrix and hard reinforcement appears to be a great challenge in machining. In this article, the influence of mechanical loads on continuously reinforced thin-walled structures during the machining of joining zones of an extruded framework profile is presented. The analyzed experiments comprise drilling and circular milling of holes, threading as well as cut-out machining. To determine the mechanical loads on tool and workpiece, force measurements were taken by using different piezoelectric devices. The analysis of the occurring forces shows that the position and orientation of the reinforcing element, relative to the tool during the machining operation, influence the maximum forces decisively. Associated mechanisms cause interrelated surface characteristics that have an effect on workpiece quality. By choosing suitable processes and machining strategies, forces could be reduced significantly accompanied by an increase of quality.