Development of a new traceable areal surface texture measuring instrument

There is a clear need in industry and academia for traceable areal surface texture measurements. To address this need traceable transfer artefacts and primary instrumentation are required. The National Physical Laboratory (NPL), UK has recently completed two projects—one to develop areal transfer artefacts and one to develop a traceable areal surface texture measuring instrument. The authors describe the development of this instrument, with a working volume of 8 mm × 8 mm × 0.1 mm. The instrument uses a co-planar air-bearing slideway to move the sample. It also uses a novel vertical displacement measuring probe, incorporating an air bearing and an electromagnetic mass-offsetting mechanism. The motions of the slideway and the probe are measured by laser interferometers, thus, ensuring traceability of the measurements to the definition of the metre. A description of the main sub-systems that make up the instrument is given and very preliminary results are presented.