Examensarbete är den avslutande delen i utbildningen till Civilingenjör, arbetets omfattning är 20 poäng av de totalt 180 poäng som utgör utbildningen. Examensarbetet har utförts på Sapa Automotive i Vetlanda.Syftet med examensarbetet har varit att ta fram en utvecklingsmetod som Sapa Automotive kan använda sig av vid sina utvecklingsprojekt, gällande själva konstruktionsarbetet, av takräcken till bilindustrin. Sapa Automotive är specialiserade inom produktutveckling och tillverkning av komponenter och system baserade på strängpressade aluminiumprofiler för fordonsindustrin. En av Sapa Automotives affärsidéer är erbjuda kunderna utveckling av takräck till personbilar. I dessa projekt tar Sapa Automotive på sig att utifrån givna designförutsättning utveckla de ingående komponenterna och sedan industrialisera den färdiga konstruktionen. Resultatet av examensarbetet var en manual som Sapa Automotive kan använda sig av vid kommande utvecklingsprojekt. Manualen innehåller CAD-metodik, dokumentationsmallar, konstruktionsriktlinjer och toleranskedjeblankett. Och även en beskrivning på hur konstruktören själv kan utföra sina egna FEM-beräkningar direkt i CAD-verktyget. / The master thesis is the final part of the Master of Science education, the thesis extent 20 points of the total 180 that the educations contains of. This master thesis has been done at Sapa Automotive in Vetlanda. The aim with the thesis was to develop a method that describes how Sapa Automotive should work in their development project, concerning the design work, of roof rails to the automotive industry. Sapa Autototive is specialized within product development and manufacturing of components containing extruded aluminum profiles to the automotive industry. One of the business areas is design and manufacturing of roof rails for passenger cars. In this projects Sapa Automotive handles the design of the parts that the roof rail is build and they also handles the industrialization of the finished design. The result of the master thesis was a guidebook that Sapa Automotive could use in their upcoming development project. The guidebook contains CAD-methods, documentation forms, design guidelines and tolerance chain form. And also descriptions on how the designer can do his/her own FEA-calculations in the CAD-program.

This investigation identifies how CAD models of typical automotive body assemblies could be defined to allow a continuous optimisation of the number of iterations required for the final design and the number of variants on the basis of Parametric Associative Design (PAD) and how methodologies for the development of surfaces, parts and assemblies of the automotive body can be represented and structured for a multiple re-use in a collaborative environment of concept phase of a Product Evolution (Formation) Process (PEP). The standardisation of optimised processes and methodologies and the enhanced interaction between all parties involved in product development could lead to improve product quality and reduce development time and hence expenses. The fundamental principles of PAD, the particular methodologies used in automotive body design and the principles of methodical development and design in general are investigated. The role which automotive body engineers play throughout the activities of the PEP is also investigated. The distribution of design work in concept teams of automotive body development and important methodologies for the design of prismatic profile areas is critically analysed. To address the role and distribution of work, 25 group work projects were carried out in cooperation with the automotive industry. Large assemblies of the automotive bodies were developed. The requirements for distributed design work have been identified and improved. The results of the investigation point towards a file based, well structured administration of a concept design, with a zone based approach. The investigation was extended to the process chain of sections, which are used for development of surfaces, parts and assemblies. Important methods were developed, optimised and validated with regard to an update safe re-use of 3D zone based CAD models instead of 2D sections. The thesis presents a thorough description of the research undertaken, details the experimental results and provides a comprehensive analysis of them. Finally it proposes a unique methodology to a zone based approach with a clearly defined process chain of sections for an update-safe re-use of design models.