Towards Surface Engineering

Doktorsavhandling, 1994

The purpose of this dissertation is to explore a route towards surface engineering both by the introduction of a conceptual framework called Interactive Surface Modelling (ISM) and by the actual application of the concept on two functional surfaces of importance to the automotive industry: cylinder liners for engines and leather imitation surfaces for the interior of cars. The results are presented in six separate but related papers concerning the construction of the ISM system shell and the use of modern technology to explore and represent the functional knowledge relevant to the specification of surface properties. Functional demands control the route from the designer's specification of suitable characterization parameters to the manufacturing engineer's choice of machining processes and data and ultimately to the quality control engineer's choice of measuring devices and measuring strategy. A prototype was developed, where two functional surfaces were implemented: the cylinder liner surface for car engines and the leather imitation surface for car interiors. The prototype system was developed in the MS-Windows environment using commercial softwares and a unique concept for the specification of desired surface properties where functional surfaces are divided into a number of separate functional requirements (more or less independent) that could separately be specified in terms of design parameters, manufacturing variables, and measuring dito. Several tools were developed for the representation of the surface topography and characterization of the functional behaviour of the surface. CAD systems were used for the representation of simulated 3D surfaces and various 3D surface roughness measuring devices were tested to see which method would give the best insight and knowledge of cylinder liner surfaces subjected to engine tests. In order to study the wear process in the cylinder liner surface, an effective relocation and replication technique was developed and measurements were made not only with traditional stylus equipments but also with Atomic Force Microscopes (AFM) that revealed some of the mechanisms of cylinder liner wear invisible to the ordinary 3D stylus technique. The introduction of the AFM measurements to the field of surface engineering was a major breakthrough for the functional characterization of surfaces in my work with the ISM concept and much points to the benefits of using the AFM to seek answers to surface engineering questions in the new world of surface features accessible to this instrument.