Measurement and analysis of surface texture and surface roughness are one of the indispensable measurements not only for quality control but also for production control, state grasping of manufacturing equipment, and research and development. This is because surface textures are deeply related to functions and qualities of products, and in research and development, the measurement and analysis of surface roughness contributes to the elucidation of the phenomenon and the achievement of high functionality and high efficiency. This review reports on the latest developments in ISO standards and analytical techniques for surface textures, especially the ISO 21920 series and plateau surface analysis, to support quality control and research and development in the Tribology field.

Contact-type form/surface-roughness measuring instruments, which scan the surface of a workpiece with a stylus to measure the form/roughness of a workpiece surface, play an important role in the quality assessment of products. Recently, in many industries, a strong demand can be found for rapid evaluation of workpieces having complex surface geometries. Also, data processing in accordance with international standards is another important issue to be addressed. To meet these requirements, the latest contact-type form and surface roughness measuring instruments are equipped with innovative hardware and software. This paper introduces the latest trends in hardware and software for contact-type profile/roughness measuring instruments.

In surface texture analysis, useful information can be obtained only after appropriate filtering is performed on the profiles obtained by the measuring machine. The Gaussian filter is generally used for filtration, however the end-effect occurs where the output is distorted at both ends of the profile. The spline filter has been attracting attention in recent years as filters that do not cause the end-effect. This article describes the fundamentals of the filtering process for the spline filter and the standard for the spline filter defined in ISO 16610. In addition, the paper introduces the latest trends in filtering algorithms such as robust filters, linear areal filters and other technologies.

The information obtained by profile measurement with a conventional contact-type surface roughness measuring instrument is information from “lines”, but by using an atomic force microscope (AFM) image, surface roughness information from “planes” can be obtained also. This paper describes the latest technological trends in profile surface roughness measurement by a metrological AFM and areal surface roughness measurement.

As parts become smaller and more precise, demand for non-contact surface texture measurement methods increases. In addition to the profile method, there is an increasing demand for areal surface texture evaluation. Various non-contact measurement methods have been standardized as the areal surface measurement method. Above all, point autofocus profiling, a non-contact measurement method standardized in ISO documents, has a high data correlation with the contact stylus type and offers non-contact areal surface texture measurement with high accuracy. It is also capable of measuring surface texture with an inclined surface, evaluating the roughness of the inner diameter and side of the inner diameter, which none of the existing measurement methods have achieved yet. In this paper, we explain the principle and features of this measurement method and introduce effective measurement examples.

In the area of precision manufacturing, there is an increasing demand for high-speed, non-contact optical surface roughness measurement. White light interferometry is a dominant technology to generate quantitative 3D images of surfaces. White light interferometry, also known as coherence scanning interferometry (CSI), is classified in Part 604 of ISO25178-6 (2010):Geometrical Product Specifications methods for measuring surface texture (GPS) ‒Surface texture: Areal ‒Part 6: Classification of methods for measuring surface texture. Coherence scanning interferometry provides quantitative maps of the surface topography for a million image points in a few seconds. This paper describes the basic technique and the latest technical trend for tribological surface structure analysis.

In ultra-smooth processed surfaces, such as semiconductor wafers, it is extremely important to control nanoscale particles on the top surface. In this paper, optical methods for detecting such nano-scale particles are first reviewed from the viewpoint of principle. Then, the latest trends in methods based on new principles are introduced.