Effect of surface topography upon the quality of autobody panels

Abstract

Improvements in the quality of the autobody panels can lead the automotive industry to large savings, where metal scrap levels always exceed 50%, and global losses are running into millions of pounds per annum. The production of new tooling also runs into the order of millions of pounds, often taking many weeks of trials to achieve the correct profiles and clearances. It is therefore important to identify the correct material to use in term of substrate mechanical properties and surface topography and coating type) in order to achieve better quality and minimise manufacturing costs. The most useful approach to surface topography characterisation in engineering is to describe a surface by a set of parameters, which can be measured objectively, correlated to functional behaviour and used for process control. The research work presented in this thesis consisted in the study of the different stages of the autobody manufacturing process through an extensive experimental activity. The phenomenon of oil retention of a surface and friction were studied and novel 3D surface topography parameters were deployed. Then, the experimental results were correlated with the surface topography parameters in order to understand how surface topography is influencing these phenomena. Finally, a similar approach was attempted with semi-industrial experimentation to probe for correlation between surface topography parameters and ability of a material to be deep drawn.