subject: The Utility Of Surface Metrology [print this page] The impact of surface geometry, in particular the roughness of the surface, can influence its behaviour and effectiveness. Surface metrology is a branch of metrology, in which the surface geometry is studied in terms of deterioration and cracks; and its behaviour in terms of adhesion, friction etc.
Broadly, the three parameters, primary, wavy and rough define the surface. The characteristics of a surface play an important role in deciding its use for producing the systems and the products. The quality of the surface defines its use for various industries and its applications; such as medical implants, semi-conductors, thin films etc.
Various techniques are available to measure the features of the surface affecting its behaviour. The technologies employed have both benefits and limitations. Therefore, making decision for using certain technique requires good understanding. It becomes very crucial to choose the right tool based on the application.
To measure the texture of the surface, the available tools are stylus profilers, White Light Interferometric Microscopes or optical profilers and confocal microscopes. The different surfaces can be measured in 2D and 3D dimensions, which are practically very useful in industrial applications. 2D surface is still quite commonly used for analysing the roughness of the surface. The trend now is moving towards 3D.
The 3D surface profilers generate accurate quantification, and provide vital information on the load carrying capacity, porosity etc. These characteristics qualify the surface for certain specific purposes. This technology also enables the measurements of certain features which are non- conventional but become a major contributor in deciding about the function and utility of the surface.
3D technology has many advantages. It can highlight the differences between surfaces, which apparently look same. They can quantify the surface topographies and highlight the differences.
The most popular technology stylus profiler is used for characterizing industrial films and coatings. The high quality and cost effective technology makes it very popular. Only confocal technology has higher vertical resolution, when compared to stylus profiler.
Optical profilers or the White Light Interferometric Microscopes are widely used in research, science and especially for quality control and assurance purposes. These assist in diagnostic purposes and provide accurate and quick measurement. These are mostly used for measuring electronic parts, which are used in industries.
Confocal microscopes are used to measure the slopes. It has high lateral resolution, particularly very practical in characterizing microptics. The optic design and the features allow the measurements to pass through transparent layers.
The precise measurements of the parts and assemblage form the basis of surface metrology. This facilitates and enables the mating of surfaces, also with high internal pressures.
