Increase of the body in white geometrical accuracy through fixtureless body shop

Abstract

Nowadays, small series in the automotive manufacturing industry are becoming more and more important, mainly because of the development of the electric car and also due to the shorter life cycles of products. In such a competitive field, where technologies are continu-ously being improved and new alternatives presented, new and more flexible manufacturing methods are required. Typical production methods in this industry present a lack of flexibility because of the use spe-cific fixtures and jigs, which normally can just be used in one or few designs. Since high investment costs are not bearable for small series, economic solutions need to be established, in order to satisfy both those manufacturers whose production volumes are small and those who develop new prototypes. As a solution, the Chair of Production Engineering of E-Mobility Components (PEM) started the ProeK project (Produktionseffizienz in der Kleinserie) in which developed a flexible concept which enables shifting the intelligence from the jig into the part, as well as an auto-mated laser welding process. This jigless body shop concept, apart from making the manufac-turing more flexible, further makes it faster and reduces the investment costs.

The basic idea is that the body parts are: first, cut by laser from metal sheets, and secondly bent to get the desired geometry. New design variations can be easily, fast and economically created modifying the CAD designs. Each piece integrates joints that act as self-positioning elements before welding, which is what makes the absence of proper fixtures possible.

Then comes the final part, the welding process, which is done by laser and solves the challenges and limitations that other methods such as spot welding and MIG welding present: distortion, high maintenance, need of flanges, etc. Moreover, it allows automation, agility and good union quality. To achieve this goals, a diverse set of laser welding parameters have been developed in previous works.

Within the Proek, aim of this Master thesis, as referred in its title, is to increase the body in white (BIW) geometrical accuracy through fixtureless Body Shop. In other words, to deal with the tolerance issue in this new manufacturing method presented by the PEM.