Surface finish metrology tutorial

Surface characterization of die inserts used for LED lamp plastic lenses

“…All different techniques provide different answers. For considerable detail regarding methods for measuring surface texture, we refer the reader to the work done by the National Institute of Standards and Technology [5,8] as well as to the ISO 25178-6:2010 [9] standard. In this project, a laser confocal microscope has been selected to measure the surface texture of the eighteen inserts as described in Section 3 of this paper.…”

Measurement of the Nanoscale Roughness by Atomic Force Microscopy: Basic Principles and Applications

“…A truncated pyramid is one type with a 90 degree included angle between the opposite sides. It is likely that a profile containing many peaks and valleys with a radius of curvature of 10 microns or less and slopes greater than 45 degrees would be misunderstood by such a stylus (Vorburguer & Raja, 1990).…”

“…If the long wavelengths are functionally relevant, then the use of a slide should be avoided. In addition, the use of a skid surfaces or surfaces with periodic discrete peaks can result in distortion of the measured profile (Vorburguer & Raja, 1990). …”

“…Before 1990's the measurement of sample surface was obtained by a contact stylus profiler (Whitehouse et al, 1975) that had limitations including a large stylus radius, a large force and low magnification in the plane and may have misrepresented the real surface topography owing to the finite dimension of the stylus tip (Vorburguer & Raja, 1990). On the ultramicroscopic scale of surface, atomic force microscopy (AFM) has been developed to obtain a three-dimensional image of a material surface on a molecular scale.…”

“…The cutoff selected must be short enough to exclude irrelevant long wavelength and at the same time long enough to ensure that enough texture has been included in the assessment to give meaningful results. Usually five cutoff settings are used for assessment, and overall traverse length is seven cutoffs (Vorburguer & Raja, 1990). …”