Accurate roughness measurements by laser interferometer calibration, VFM-uncertainty calculations and noise reduction

H. Haitjema; M. A. A. Morel

doi:10.1117/12.614858

18 August 2005 Accurate roughness measurements by laser interferometer calibration, VFM-uncertainty calculations and noise reduction

H. Haitjema, M. A. A. Morel

Author Affiliations +

Proceedings Volume 5879, Recent Developments in Traceable Dimensional Measurements III; 58790I (2005) https://doi.org/10.1117/12.614858
Event: Optics and Photonics 2005, 2005, San Diego, California, United States

Abstract

Normally, roughness measurements are carried out with a rather high uncertainty ranging to a few percent up to 10%. This is a rather bad situation considering the accuracy of primary length standards (1:5•10^11) and common dimensional measurements(1:10⁶). In this paper we show that with laser interferometer calibration techniques and extensive uncertainty evaluations this situation can be improved. As the probe of a roughness measuring instrument moves dynamically, a probe calibration should be carried out dynamical as well, in the same frequency range as in which the probe normally operates. For this, a simple yet very effective dynamic probe calibration device has been designed, where the traceability is achieved by a laser interferometric read-out with 30 kHz and 10 nm resolution. With this device a probe can be fully characterized for various amplitudes and frequencies. It is shown that for a Mitutoyo roughness measuring machine the deviations stay well within 1%. Uncertainty estimations for roughness measurements are not straightforward, therefore one takes for safety often quite high estimates for effects like probe size and measurement force. With the VFM ('Virtual Form Measurement') concept this problem is treated by simulating the measurement on the same surface as actually measured, while varying probe diameter, filtering, probe angle, noise etc. and estimating the influence of all these circumstances on the calculated parameter. In this way a task-specific uncertainty estimation is obtained with an outcome which is mostly lower than expected. This is shown with some examples. With improved noise reduction techniques the basic uncertainty can be reduced to the nm-level for the roughness tester used.

Citation Download Citation

H. Haitjema and M. A. A. Morel "Accurate roughness measurements by laser interferometer calibration, VFM-uncertainty calculations and noise reduction", Proc. SPIE 5879, Recent Developments in Traceable Dimensional Measurements III, 58790I (18 August 2005); https://doi.org/10.1117/12.614858

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available