Chetwynd, D*; Howell, G*; Leach, R K (2002) Evaluation of the dynamic performance of a glass cantilever style constant force probe for the measurement of surface texture. NPL Report. CBTLM 23

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Abstract

A prototype surface topography contact probe based on a glass cantilever with capacitive micrometry to detect displacement has been evaluated under relatively extreme dynamic conditions. The probe is designed principally for low contact force measurements on sub-micrometre surface structures and to be scanned at speeds well below 1 mm s-1. Its behaviour at higher speeds might be predicted by modelling it as a second-order system, but the complexity of interaction between a tip and surface casts doubts on how such models should be used. Hence a high-precision air-bearing table has been used to scan nickle replica sinusoidal surface profiles under the tip. This has allowed experimental verification of behaviour at speeds beyond 1 m s-1 and at profile signal frequencies above the probe natural frequency (about 280 Hz). An extremely consistent output is reported under all test conditions with the frequency response flat to within 1 dB up to around 250 Hz. It is concluded that the probe technology may be used satisfactorily for measurements at speeds higher than are used on conventional surface metrology instruments.

Item Type:	Report/Guide (NPL Report)
NPL Report No.:	CBTLM 23
Subjects:	Engineering Measurements Engineering Measurements > Dimensional
Last Modified:	02 Feb 2018 13:17
URI:	https://eprintspublications.npl.co.uk/id/eprint/2461