An approach of assessment for ultra-precision V-groove structured surfaces

Freeform and structured surfaces offer enhanced function properties over component having conventional surface finishes. They are increasingly being used in various applications for optimised functionality such as optical or tribological properties. In the last few decades a great amount of effort has been made in the research and manufacturing of micro and nano scaled freeform and structured surface components. Measurement and assessment of these kinds of surfaces remains a significant “bottle neck” of manufacturing processes and consequently a good deal of research is being carried out to address these problems In this paper, assessments of surface features of two film replicas of diamond turned ultra-high precision V-groove roll (drum) surfaces in the measurement laboratory are presented. Two film replica samples of different parts of the same drum, which differ finish following an interrupted cut are used for the assessments. Various methodologies for obtaining a valid assessment of the surfaces using commercially available surface metrology instruments have been applied, including SEM, stylus instrument and white light interferometry methods. The measurement results are discussed and the best practice for the assessment of precision V groove structured surfaces in a measurement laboratory using commercial instruments is outlined. The future on-line inspections of diamond turned ultra-high precision V-groove drums and other freeform structured surface components are proposed.