Analysis of Attachment Techniques of Exterior Parts in Car Assembly - A Technical Evaluation

Abstract: E2017:028, This thesis has been carried out with the purpose to provide knowledge and helpCEVT in future decision-making processes of selecting suitable attachment techniquesfor joining exterior car body parts in order to enable an efficient productionof competitive cars.The thesis has been performed at Chalmers University of Technology in cooperationwith CEVT AB, a development centre for future cars of the Geely Group.Companies active in the car industry uses different methods when fastening plasticexterior car body parts and standardized solution is yet to be found. Previousresearch of development is limited in this area and the issue comes and goes in accordanceto automotive trends. Instead, current fastening methods are based mostlyon practical experience and knowledge. On behalf of CEVT, an evaluation is maderegarding which fastening method is preferable to use for attaching exterior car bodyparts with respect to cost, quality, productivity and ergonomics. This area is thereforeof great interest to the car manufacturing industry in addition to its suppliersand customers. Hence, this thesis delivers:• A complete analysis of the fastening methods used in car manufacturing ofexterior car body parts• An evaluation matrix that treats qualitative data• A cost model tool designed to help CEVT compare investments and returnrate of the fastening methods• Guidelines regarding design aspects and common quality issues for the fasteningmethodsThe course of this thesis is based on interviews with suppliers and experts in combinationwith study visits at Volvo Car’s production plant as well as technical workshops.The results of this thesis shows that a majority of today’s car manufacturersuses mechanical attachments for joining exterior car body parts and only a minoritygroup of pioneers combines mechanical attachments with adhesive tape for wheelfender flare extensions. The process mapping and time studies shows that adhesivetaping is a more complex and time demanding process in production when comparedto snap-fit fasteners. The study has shown that it is not about what fasteningmethod to use, it is about how to design for the right application. The use of immaturemethods is a symptom of a larger, organizational problem caused by latechanges, which should be further explored.