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Christian Munzinger, Gisela Lanza, Daniel Ruch and Jörg Elser:
In: Production Engineering, Volume 4, Numbers 2-3 (2010), 193-201, DOI: 10.1007/s11740-010-0209-6
Spatially curved Al-extrusion profiles are often used for lightweight frame structures in vehicle manufacturing. Within the Collaborative Research Centre SFB/Transregio 10, an automated product-flexible process chain is established in order to produce and machine such profiles and to join them into frame structures. One of the biggest challenges of this process chain consists in handling, clamping and machining variably formed profiles with precision and without having to change the mechanical system. For this, both the contour of the profile and the position and orientation of the profile during the process have to be determined. In order to have this information provided from inside the process chain, a component-specific scale was developed and realised for the contour detection and precision positioning of multi-dimensionally curved extrusion profiles. The scale is applied onto the surface of the profile by a laser. To determine the contour, the scale is scanned using digital image processing and the profile is measured by a laser triangulation sensor. This establishes the relation between component scale and profile contour. If required, the position of the profile can be readjusted by scanning individual markings again during machining. It is not necessary to re-measure the entire profile contour. The process can be used for different profile contours and profile lengths without having to change the mechanical system. The first section of this article describes the approach for contour detection and precision positioning and its validation for straight profiles, 2D curved profiles and 3D curved profiles with a test rig. Then, the implementation of the validated process into a process chain is described, including the inline application of the scale, the inline profile measuring and the precision positioning of spatially curved profiles during machining.