On variation of surface topography and robust product performance

The customer's demands for higher quality,faster delivery times and reduction of cost,give evidence for the need to develop new technologies or enhance existing technologies combined with research activities.The automotive industry's capability to develop new products in a shorter time is constantly improved.Tool and die creation is a major part of the product creation for many industrial products and in particular for the automotive industry.The higher product requirements on reduced weight,better safety,and lower emissions have meant that a larger number of automotive body parts must be made in advanced high strength steels.Improved functionality of surface textures and engineered tailor made component surfaces is one enabling technology for industry to increase compete ability by improved component function and reduced friction losses.However,material properties'variation,un-evenly spread wear,unknown manufacturing process variations,the“human factor”,faulty metrology procedures…All factors interact to increase the problems of utilizing surface texturing on the micro metre level as a competitive tool for industry.Large variation of the micro topography created by industrial machining processes tends to reduce the impact of the usage of improved engineered surfaces on critical components.A proposal of a strategy for metrology using"intelligent"sampling techniques comprising of regionalization of the functional area and designed sampling patterns is presented.To efficiently make use of efficient sampling,an example of a recently developed optical scattering light in-line metrology of high precision surfaces is discussed as a tool to enable efficient control of machine tools in general.Future steps discussed include developing of control loops for implementation in CNC controllers to efficiently make use of the"smart"surface texture characterisation data from the developed in-line surface texture sensors.

A solution to the hydrodynamic lubrication of a circular point contact sliding over a flat surface with cavitation

This letter presents an analytical solution to the hydrodynamic lubrication of a circular point contact sliding over a flat surface with cavitation.The solution is found by solving the Reynolds equation with Reynolds boundary condition for cavitation.The cavitation boundary is shown to be straight lines directed 108.4°against the sliding direction.The result is experimentally verified in the limit of large values of viscosity,sliding velocity and radius of a spherical ball.The solution raises questions about the coupling between cavitation and film rupture and can be used as an independent check on the validity of numerical solutions.