Abstract
Improved metrological capabilities for three-dimensional (3D) measurements of various complex micro- and nanoparts are increasingly in demand. This paper gives an overview of the research activities carried out by the Physikalisch-Technische Bundesanstalt (PTB), the national metrology institute of Germany, to meet this demand. Examples of recent research advances in the development of instrumentation and calibration standards are presented. An ultra-precision nanopositioning and nanomeasuring machine (NMM) has been upgraded with regard to its mirror corner, interferometers and angle sensors, as well as its weight compensation, its electronic controller, its vibration damping stage and its instrument chamber. Its positioning noise has been greatly reduced, e.g., from 1σ = 0.52 nm to 1σ = 0.13 nm for the z-axis. The well-known tactile-optical fibre probe has been further improved with regard to its 3D measurement capability, isotropic probing stiffness and dual-sphere probing styli. A 3D atomic force microscope (AFM) and assembled cantilever probes (ACPs) have been developed which allow full 3D measurements of smaller features with sizes from a few micrometres down to tens of nanometres. In addition, several measurement standards for force, geometry, contour and microgear measurements have been introduced. A type of geometry calibration artefact, referred to as the “3D Aztec artefact”, has been developed which applies wet-etched micro-pyramidal marks for defining reference coordinates in 3D space. Compared to conventional calibration artefacts, it has advantages such as a good surface quality, a well-defined geometry and cost-effective manufacturing. A task-specific micro-contour calibration standard has been further developed for ensuring the traceability of, e.g., high-precision optical measurements at microgeometries. A workpiece-like microgear standard embodying different gear geometries (modules ranging from 0.1 mm to 1 mm) has also been developed at the Physikalisch-Technische Bundesanstalt.
Highlights
Following the progressive miniaturization of today’s manufacturing processes, more and more micro- and nanoparts with a complex geometry are applied to numerous industrial products, such as those in the automotive, medical, robotics and telecommunications fields
Several micro-coordinate measuring machine (CMM) probes are being further developed at Physikalisch-Technische Bundesanstalt (PTB), including a boss-membrane piezoresistive microprobe, a fibre probe and probes based on atomic force microscope (AFM)
At PTB, we have developed a 3D‐AFM [39] and the so‐called assembled cantilever probe [40], on which measurement is promising toapplication
Summary
Following the progressive miniaturization of today’s manufacturing processes, more and more micro- and nanoparts with a complex geometry are applied to numerous industrial products, such as those in the automotive, medical, robotics and telecommunications fields. Laboratory of the United Kingdom in the year 1999 In its configuration, they applied a mirror corner near the CMM probe as reference mirrors and utilized three laser interferometers and three autocollimators to measure the probe position with respect to the metrology frame. Almost at the same time, Vermeulen et al [5] developed a micro-CMM where linear scales are applied to measure the position of the probe tip fully in compliance with the Abbe principle in the x- and y-directions with a motion volume of 100 mm × 100 mm × 50 mm. The contact mode microprobes usually apply styli with a limited aspect ratio to achieve a better measurement stability To mitigate these problems, non-contact mode micro-CMM probes have been developed [21,22,23]. This paper is focused on giving an overview of the research activities carried out at PTB
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