Stylus Method Research Articles

Instantaneous velocity displacement and contour measurement by use of shadow moiré and temporal wavelet analysis.

A temporal wavelet analysis method is proposed for velocity, displacement, and three-dimensional surface-profile measurement of a continuously deforming object by use of the shadow moiré technique. A grating is placed close to a deforming object, and its shadow is observed through the grating. The moiré fringe patterns, generated by the interference of the grating lines and their shadows, are captured by a high-speed CCD camera with a telecentric gauging lens. Instantaneous frequency of gray-value variation is evaluated point by point with the continuous wavelet transform. From the instantaneous frequency of each point on the object, the velocity, displacement, and high-quality surface profile at different instants can be retrieved. In this application, two specimens are tested to demonstrate the validity of the proposed method: One is a small coin with a rigid body motion, and the other is a simply supported beam subjected to a central point load. The results are compared with those obtained from temporal Fourier-transform and mechanical stylus methods.

Investigation of silicon oxynitride and amorphous silicon multilayers

Optical (refractive index) and structural properties of silicon oxynitride (SiON) and amorphous silicon (a-Si) multilayers grown by RF sputtering with thickness in the 10–30 nm range have been analysed by ellipsometry and TEM. Satisfactory agreement between the two techniques is obtained as regards the thickness determination of the SiON films. Disagreement with values obtained by the stylus method by extrapolation for the two types of layers is discussed. The interfaces of the SiON films are very good when n-type P doped Si is used as a target. They are wavy with average periodicity and amplitude on the order of 50 and 2 nm, respectively, when a semi-insulating Si target is used, despite the presence of a buffer layer. Hypothesis is made that P incorporation may improve the reconstruction of the SiON surface.

Determination of surface contour by temporal analysis of shadow moiré fringes

A simple temporal analysis algorithm (phase scanning method) is proposed for 3-D surface profile measurement of a vibrating object based on shadow moiré technique. A grating is positioned close to a low-frequency vibrating object and its shadow is observed through the grating. The moiré fringe patterns, generated by the interference of grating lines and shadow lines, are captured by a high-speed CCD camera with a telecentric gauging lens. Phase values are evaluated point by point using phase scanning method. From the phase values of each point on the object, the high-quality surface profile of the specimen at different instants of vibration can be retrieved. In this application, two specimens are tested to demonstrate the validity of the method, one is a spherical cap with height of 4 mm, the other is a small coin with unevenness of less than 0.2 mm. The experimental results are compared with test results using mechanical stylus method.

Preparation of sub-nanometer thickness-controlled tin dioxide films by pulsed atomic-layer CVD

Tin dioxide coatings of sub-nanometer thickness on glass were prepared between 325 and 525 °C by pulsed atomic-layer chemical vapor deposition. The sample films grown on substrates at 400 to 450 °C exhibited a constant growth rate of 1.6 Å/cycle, corresponding to one-fourth the length of tin dioxide (110) lattice spacings. We propose herein a dry method of thickness measurement for very thin, sub-nanometer-thick films based on X-ray photoelectron spectroscopy depth profiles using argon ion sputtering and etching time values calibrated using both stylus and optical interference methods for tin dioxide films. The preferred orientations of the films are (110) and (100), and the tentative grain size is 80×100 nm for 10-nm-thick films. Optical transmittance for visible light exceeds 0.9, and optical absorption edges at room temperature occur at 3.75 eV. Ultra-violet photoelectron spectroscopy (UPS) measurements of the electronic density of states are performed on as-grown films surfaces.

Shape measurement by use of liquid-crystal display fringe projection with two-step phase shifting.

The use of an optical fringe projection method with two-step phase shifting for three-dimensional (3-D) shape measurement of small objects is described. In this method, sinusoidal linear fringes are projected onto an object's surface by a programmable liquid-crystal display (LCD) projector and a long-working-distance microscope (LWDM). The image of the fringe pattern is captured by another LWDM and a CCD camera and processed by a phase-shifting technique. Usually a minimum of three phase-shifted fringe patterns is necessary for extraction of the object shape. In this method, a new algorithm based on a two-step phase-shifting technique produces the 3-D object shape. Unlike in the conventional method, phase unwrapping is performed directly by use of an arccosine function without the need for a wrapped phase map. Hence, shape measurement can be speeded up greatly with this approach. A small coin is evaluated to demonstrate the validity of the proposed measurement method, and the experimental results are compared with those of the four-step phase-shifting method and the conventional mechanical stylus method.

The model of surface roughness inspection by vision system in turning

The paper presents a system for measuring surface roughness of turned parts through computer vision system. The images of specimens grabbed by the computer vision system could be treated by some techniques to get the features of image texture (major peak frequency F1, principal component magnitude squared value F2, and the standard deviation of grey level STD). These features could be used as input data of a abductive network. Using the trained abductive network, the experimental result had shown that the surface roughness of turned parts measured by computer vision system over a wide range of turning conditions could be got with a reasonable accuracy compared with those measured by traditional stylus method. Comparing with the stylus method, the constructed computer vision system is a useful method for measuring the surface roughness with faster, lower price, and lower environment noise in manufacturing process.

A Study of Computer Vision for Measuring Surface Roughness in the Turning Process

The paper presents a system for measuring the surface roughness of turned parts using a computer vision system. The images of specimens grabbed by the computer vision system are processed to obtain parameters of their grey levels (spatial frequency, arithmetic mean value, and standard deviation). These parameters are used as input data to a polynomial network. Using the trained polynomial network, the experimental result shows that the surface roughness of a turned part made of S55C steel, measured by the computer vision system over a wide range of turning conditions, can be obtained with reasonable accuracy, compared to that measured by a traditional stylus method. Compared with the stylus method, the computer vision system constructed is a useful method for measuring the surface roughness of this material faster, at a lower cost, and with lower environmental noise.

108 超精密切削加工された純アルミニウムの触針式表面粗さ測定(O.S.1-2 精密切削加工)(O.S.1 : 高精密加工)

108 超精密切削加工された純アルミニウムの触針式表面粗さ測定(O.S.1-2 精密切削加工)(O.S.1 : 高精密加工)

Stylus damage prevention index

Stylus methods for measuring surfaces have sometimes been blamed for causing damage to the surface because of the stylus pressure. This paper investigates this possibility and develops a ‘potential damage index’ which takes into account the instrument parameters, static and dynamic, and surface parameters. All types of surface are considered, both periodic and random. The paper shows that the stylus method is often misjudged, that stylus damage is rare and that any damage observed is likely to be due to the operation of a skid in the instrument.

Characterization of surface topography by confocal microscopy: II. The micro and macro surface irregularities

In part I, considering the autofocus and intensity methods of measurement, the principles and performance of a confocal microscope were discussed. In this part, the details of the experiments, conducted to measure and assess micro and macro surface irregularities of various machined planar and cylindrical surfaces, using a confocal scanning optical microscope (CSOM) are described. The three-dimensional surface topographies of various machined planar surfaces and also the form errors, like roundness and cylindricity, are measured and analysed. The significance of the set of new parameters, proposed for characterizing three-dimensional surface roughness and roundness measurements, is indicated. The effect of filtering on the variation in values of three-dimensional surface-topography parameters is studied. The performance of the CSOM is compared with those of conventional stylus and interferometric methods. The system is shown to have a great number of advantages in terms of three-dimensional surface mapping of planar and cylindrical surfaces and recognition of details and analysis for characterization of surfaces.

Comparison of two stylus methods for measuring surface texture

Objectives: The purpose of this study was to evaluate and compare two “stylus” methods for measuring surface texture of dental tissues and materials Methods: The two styli chosen were a contact diamond stylus and a non-contact focussed laser stylus attached to the same measuring apparatus. Results: These indicate that there are significant differences between those obtained from surface texture measurements using a non-contact laser stylus and a diamond contact stylus method despite being mounted in the same profilometer. This is valid for both the test specimens of known surface texture, provided by the manufacturers, and for a “real world” simulation using contoured and finished Dicor ceramic blocks. The only significant agreement between the two styli was found for the R a parameter. This should not be used alone to describe the roughness of a surface because the parameter is not sensitive to profile shape. Owing to the properties of the stylus used it is essential that the limitations of surface profilometry be recognised. Significance: Caution should be exercised when comparing the results of surface texture studies of dental hard tissues and restorative materials using varying types of stylus attached to a surface profilometer.

Laser diffraction method of surface roughness measurement

Traditional contact probe and stylus methods have been difficult to apply for the measurement of the roughness of sculptured surfaces, especially whose positioned at under high inclination. The laser diffraction method is presented as a method for remote surface roughness measurement that can be used directly on a machine tool or a press for any position of complex sculptured surfaces. This method can be used to measure the surface roughness of various materials, both metals and non-metals, as well as hard ceramic and soft plastic such as for rapid prototyping. The main technical difference of the method suggested is the use of a new optical system and the automatic determination of the luminous radiation reflection coefficient by a proposed analytical dependence. Specifically, the method involves the simultaneous measurement of the mirror reflected radiation beams as well as the scattered spectrum component and then the numerical processing of reflected laser light signal by developed software. The measurement results taken for different machining processes of complex sculptured surfaces have shown a good correlation with the results of stylus methods.

Ｆｒａｕｎｈｏｆｅｒ回析による超精密加工表面粗さ測定装置の開発研究 光学系誤差の補正法

In this paper, we propose a new optical measuring method which can be applied to in-process measurement of root mean square roughness (Rrms) of ultra-fine finished surface with an accuracy of sub-nanometer. The principle of our method is based on the Fraunhofer diffraction theory with taking account of Gaussian laser beam propagation. The automated random micro-roughness measuring system is developed based on the principle. Practically, the optical parts composing optical system in which laser beam propagates are taken as the diffractive and scattering body, so the systematic error which is defined as optical system roughness is occurred. In order to enable more accurate measurement by eliminating this error, calibration method based on theoretical analysis is introduced. This method is performed by using a reference surface of which surface roughness is measured by using the traditional stylus method with high reliability. The measurements of the ultra-fine polished silicon wafers with the micro-roughness of sub-nanometer order are carried out by using the developed measuring system of which optical system roughness is calibrated. And the silicon wafers are measured by using the ZYGO profiling instrument for checking surface roughnesses. It is shown that the developed measuring sensor which is calibrated is valid for measuring random micro-roughness within a nanometer.

Surface roughening resulting from ion irradiation of multilayered materials

The surface topography of multilayered W/Cu structures is studied after 100–340 keV Ne + and Ar + irradiation in the range of fluences up to 10 17 cm −2 employing the stylus method. The characteristic features on the surface are correlated with the experimental results obtained when measuring stress relaxation during ion irradiation by employing the bending technique and free-lattice parameter using the sin 2ψ method. Surface roughness, as a function of sputtering and target parameters, is analyzed theoretically and experimentally. Qualitative agreement is obtained. The correlation between the surface characteristic features initiated by ion irradiation and stress relaxation processes in multilayers is demonstrated.

Atomic force microscopy for thin film analysis

Atomic force microscopy (AFM) was used to study a variety of surface effects present in embossed structures, thin film coatings, and polymeric substrates. Comparisons between scanning electron microscopy (SEM), optical microscopy and stylus methods of characterizing surface morphology show that AFM reveals information in three-dimensional format not previously available.

研削加工面の三次元的評価のための断面曲線の走査位置補正法

A method is proposed for compensation of fluctuations in scanning speed of surface profile curves of ground parts. In the measuring of machined surfaces with the stylus method, the scanning speed of a stylus for the measurement of machine surfaces can fluctuate and the observed curves inevitably have errors in the scanning direction. This is not fatal in analysis of a single curve, however, in three dimensional analysis using plural curves, the existence of these fluctuations is critical. Compensation of the scanning length is required, in this case, to characterize machined surfaces. The method proposed identifies the positions on a profile which were formed by same abrasives, and enable the fluctuated profile curves to be used for effective three dimensional analysis. The identification of shapes formed by a same abrasive is important to analyze the behavior of abrasives on a grinding wheel. The method is based on the concept of minimization of an index function, which is designed to evaluate the differences of a couple of curves. Using this method, periodicity on a ground surface due to rotation of a grinding wheel was isolated, which is not perceptible without compensation.

X-ray reflectivity study of r.f.-sputtered thin SiO 2 films

X-ray reflectivity investigations have been performed on thin amorphous SiO 2 films obtained by r.f.-sputtering of fused quartz onto Si single crystals in an argon atmosphere. This is a non-destructive technique to determine thickness and density as well as the interface and surface roughness. For the SiO 2/Si system (small differences in density) the X-ray reflectivity is sufficiently sensitive to provide precise information on the occurence of an intermediate layer we obtained only on well-polished silicon wafers. The thickness of the films is compared with that obtained from ellipsometry data and mechanical scanning measurements (stylus method).

X-Ray Reflectivity Study of Reactive DC Sputter Deposited Al2O3Thin Films

X-ray reflection was performed on Al2O3thin films obtained by dc magnetron sputtering of aluminium in an argon/oxygen atmosphere. Two kind of films (amorphous andγ-Al2O3) were deposited on polished silicon wafers by conventional sputtering and sputtering with ion bombardment on the growing film. The x-ray reflection allows one to determine the surface roughness, mass density and thickness. The thickness was compared with ellipsometry data, and mechanical scanning measurements (stylus method). Transmission electron diffraction investigations were made for phase determination.

Effect of iodine on electrical conduction in cellulose acetate-butyrate polymer films

Electrical properties can be tailored to a specific requirement by the addition of suitable dopant materials. A few studies on the effect of an impurity such as iodine on the conductivity of polymers are available, e.g. polyethylene [1, 2], poly(vinyl acetate) [3] , poly(vinyl chloride) [4] , poly(vinyl fluoride) [5] and poly(vinyl formal) [6]. The electrical conduction mechanism in cellulose acetate-butyrate films was investigated and the results were reported in [7]. In continuation of these studies, the conduction mechanism in iodine-doped cellulose acetate-butyrate films was investigated as a function of the dopant concentration, field and temperature, and is discussed in this letter. Pure and iodine-doped cellulose acetate-butyrate films of thickness 5/xm were grown by isothermal immersion [8] of glass substrates coated with metal electrodes. The films were dried in an hot-air oven for 24 h at a temperature of around 350 K. The top electrode was vacuum evaporated on the dried films. The thickness of the films was measured using the mechanical stylus method and was verified by the capacitance method. The electrical conduction of pure and doped cellulose acetate-butyrate films was studied in the sandwich configuration. The conductivity of the film was measured as a function of temperature, using a stabilised d.c. power supply, an electrometer (Keithley 617C) and a digital voltmeter. Before actual measurements were made, the films were annealed as described in [9]. The optical absorption measurements were made using a Hitachi U3400 u.v.visible spectrophotometer. Fig. 1 shows the conductivity of pure and iodinedoped cellulose acetate-butyrate films at a field strength of 5 x 106 Vm -1. Curve a corresponds to pure cellulose acetate-butyrate films and curves b-g correspond to iodine-doped cellulose acetate-butyrate films having iodine concentrations of 0.1, 0.25, 0.5, 0.75, 1.0 and 2.0 wt%, respectively. From the plots it is seen that the conductivity increases with temperature consist of two distinct regions of conduction. From the plots it is clear that the conductivity in the sample increases with increasing concentration of iodine up to 0.5 wt %. Above this concentration, however, the conductivity is found to decrease continuously with increasing iodine concentration. It is also observed that the conductivity in the doped sample is always more than that in the pure sample, even at higher concentration. The conductivity of the samples at 300 and 400 K are shown in Table I.

Texture analysis of rough surfaces using optical Fourier transform

An optical Fourier transform technique was developed in conjunction with a machine vision system to study the texture of machined surfaces having a wide range of roughness. Surface-ground samples of different materials were used in the study. The spectra obtained by the optical method were compared with those obtained by the stylus method in terms of spectrum peak and RMS value. Correlation curves were obtained to indicate the relationship between the texture parameters and the average roughness Ra for different materials. Optical roughness correlation curves were also obtained for roughness measurement along the lay direction and subsequently for specimens coated with oil.