No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
A Novel On-line Surface Roughness Measuring Method
... Though many researchers have proposed techniques for visually inspecting conventionally manufactured components [47,48,49,50,51,52,53,54,55] an inspection of AM components is still in its infancy. Titanium alloys have very high fracture toughness and corrosion resistance. ...
Two speckle patterns produced from the same rough surface by two different illuminations are correlated. The correlation depends on the surface roughness. The two illuminations were obtained here by varying the angle of incidence of a coherent plane wave on the surface. The speckle patterns are recorded on the same film by double exposure. By placing this film in a convergent laser beam, Young fringes are observed in the Fourier plane. The correlation of the speckle patterns is obtained by measuring the visibility of the fringes. The theoretical calculations have been performed for a normally distributed surface. The experimental results are in good agreement with theory.
Summary The main factor contributing to hydroplaning on slick runways is the existence of a squeeze film in the contact area between tyre and surface. The situation may be improved by optimising surface texture so that the asperities break through the water film in a minimum time. Two techniques are described for characterising surface texture: a superposition solution based on viscous channel flow and a dimensionless number approach involving size, spacing and shape factors. The “feel” of a surface is quantitatively obtained, and an outflow meter is described which, by directly measuring the mean hydraulic radius of runways, provides a comparison of their drainage abilities.
The aim is to review the connection between light scattering and surface finish. Whilst a large amount of theoretical work has been done on light scattering, little work seems to have been done on the connection between actual engineering surfaces and light scattering. The connection between surface parameters and surface function has been well documented, and a tabular summary of this relationship is given. Various methods for measuring the light scattering properties of surfaces classified from a practical and theoretical standpoint with possible applications along with a brief review of general light scattering theory. Finally, the performance of a real time surface inspection system using light scattering is discussed.
The state of the art in the study of laser speckle patterns is reviewed,
with speckle phenomena treated as useful tools or as noise. Statistical
properties of speckle patterns (autocorrelations, spectra), blurred or
integrated, and covered along with speckle patterns in partially
coherent light (polychromatic or quasimonochromatic). Techniques for
minimizing speckle noise in holography are examined in detail. The use
of speckle patterns in information processing and storage and in
interferometry are discussed separately. Speckle photography, electronic
speckle pattern interferometry (ESPI), speckle holography, stellar
speckle interferometry, and speckle interferometry using photographic
recording are among the topics discussed.
The paper describes a simple optical-mechanical instrument which gives a rapid assessment of the surface texture of machined surfaces. The action of the instrument depends on the variation of the specular reflexion of the surface with varying angle of incidence. The variation of specular reflexion is assessed by observation of the variation in the definition of the images from an illuminated screen consisting of a series of lines. Two methods of use of the instrument are described, one as a comparator and the other for direct measurement. Using surface-ground mild-steel surfaces the experimental and theoretical relation between the response of the instrument and the centre line average value obtained, using a Talysurf, are given.
The angular distribution of the light scattered by a rough surface contains information on the texture of the surface. Profiles of nine specimens were measured with a stylus instrument and angular distributions of the scattered light were measured with a detector. The rms roughness of a surface that has an identifiable specular beam can be determined from the relative intensity of that beam. The autocorrelation length and the parameters that define the autocorrelation function, as well as the roughness of rougher surfaces that produce no specular beam, can in principle be determined by fitting the distribution computed from a model of a random rough surface to the measured distribution. In practice, measurement errors and computation errors preclude the determination of these parameters by a leastââ¬â?squares fit. Angular distributions were also computed from the surface profiles using a simplified model of the electromagnetic scattering.
The rms roughness and correlation length are determined by measuring the
degree of coherence for a fluctuating laser beam transmitted from a
moving rough surface illuminated by a diverging beam. The determination
is made by using the theoretical formula derived on the assumption that
the rough surface is a phase filter. In case of the adequately small
spread of the illumination beam and optically smooth roughness, the
measured variations of the degree of coherence are in good agreement
with the theoretical calculation, and the rms roughness and correlation
length of ground glasses can be evaluated. The experimental results
support the assumption that the statistics of the surface irregularities
is characterized by the Gaussian distribution and correlation functions.
The limitations on the dimensions of two diffracting apertures and on
the beam spread are demonstrated and discussed.
A survey of existing gloss measuring methods is given in this paper. Relations are established between subjective gloss, surface roughness parameters, and glossmeter readings on an optical bench for several types of surfaces.
We consider the theoretical form of the probability density function of the intensity in a polychromatic speckle pattern. Measurements using a multimode argon laser are compared with theory.
An experimental investigation is made of the effect of surface roughness on the statistical distribution of image speckle intensity. A speckle pattern is formed by spatially coherent light at the image plane of an object having some surface roughness and its statistical properties are investigated. It is found that the contrast of the speckle is related to the surface roughness. By this relation, a new technique for the measurement of surface roughness is proposed.
Conditions which allow the reliable measurement of the power spectrum of opaque rough surfaces by direct optical Fourier transformation were determined. The relation of the spectrum of the surface irregularities to the optically observed spectrum is discussed and the experimental results obtained to date with a transform apparatus are presented. Consideration is given to the range of roughness values to which the method may be reliably applied.
A report is given of preliminary work on a process of studying surface roughness of materials. The technique analyzes the statistics of the Fourier components of the surface roughness and uses conventional optical data processing procedures.
Beckmann, II Scattering of Light by Rough Surfaces, Editor(s): E. Wolf
- W L Anderson
Anderson, W.L., Surface roughness studies by optical processing methods, Proceedings IEEE Letters, pp. 57-95,1969.
Beckmann, II Scattering of Light by Rough Surfaces, Editor(s): E. Wolf, Progress in Optics, Elsevier, vol. 6, pp. 53-69, 1967.
A survey methods of measuring smoothness of the wood
- A Elmendorf
- T W Vaughan
Elmendorf A. and Vaughan T.W., A survey methods of measuring smoothness of the wood., Optics in Engineering,
vol.8, pp.275-282, 1958.
Optical method for the determination of surface roughness
- J F Kayser
Kayser J.F., Optical method for the determination of surface roughness, Foundry trade journal, vol.70, pp.137-138.
Taper sectioning as a means of describing the surface contour of metals, Proceeding Conference on friction and surface finish
- H R Nelson
Nelson, H.R., Taper sectioning as a means of describing the surface contour of metals, Proceeding Conference on
friction and surface finish, 2 nd edition, 217-237 (MIT Press Cambridge).
Application of inductive heads for non-contact measurement of surface finish
- V Radhakrishnan
Radhakrishnan V., Application of inductive heads for non-contact measurement of surface finish, Proceedings on
International conference of production engineering, Institution of Engineers (India), Calcutta, vol.2, pp.80-89,1977.
A light projection technique for studying surface topology
- M C Shaw
Shaw M.C., and Peklenik, A light projection technique for studying surface topology, Annals of CIRP, vol.12, pp.93-97, 1963.
Surface finish measurement by an electrical capacitance technique, Proceedings Institution of Mechanical Engineers, part 3K
- K F Sherwood
- J R Crookall
Sherwood K.F. and Crookall J.R., Surface finish measurement by an electrical capacitance technique, Proceedings
Institution of Mechanical Engineers, part 3K, pp. 344-349, 1967.
Way S., Description and observation of metal surfaces, Proceeding Conference on Friction and surface finish
- S K Vashisht
Vashisht S.K., and Radhakrishnan V., Surface studies with gloss meter, Tribology, vol.7, pp.70-76.,1974.
Way S., Description and observation of metal surfaces, Proceeding Conference on Friction and surface finish, pp.44-75, 2nd Edition, (MIT Press Cambridge, Mass.), 1969.