IMEKO Event Proceedings Search

Page 895 of 936 Results 8941 - 8950 of 9356

Ch. Papageorgiou, Th. Laopoulos
ACCURATE DISPLACEMENT MEASUREMENT BASED ON THE FREQUENCY VARIATION MONITORING OF ULTRASONIC SIGNALS

This paper introduces a different approach to the measurement of the time-of-flight of ultrasonic signals. Frequency variation monitoring and recording is used to determine accurately the arrival time of the ultrasonic signal. A high speed Digital Signal Processor (D.S.P.) is used for both: transmission and direct measurement of the frequency of the incoming signal in every single period and with an accuracy of about 0.1%. The proposed configuration offers small size and low cost solution to displacement measurements with a remarkable performance in terms of accuracy, range and measurement time.

José Sánchez, Saúl Santillán, Sergio Padilla, Benjamín Valera, Rigoberto Nava, Gerardo Ruiz
VIRTUAL INSTRUMENTATION, OVERCOMING NON-LINEARITIES WHEN ERRORS OF MULTIAXIS MACHINES ARE AMPLIFIED

Abstract - One purpose of Virtual Instrumentation in Metrology, is to empathise properties that put instrumentation away from idealisations. In actual instrumentation, geometric deviations trend to occur in relations 10-5, 10-7 of maximum displacements, requiring their representation in amplified way. If distortion of mechanisms is amplified hundreds times for its representation in CAD, many problems occur: linearity is lost between geometric relations; it is difficult to represent errors simultaneously for many axis and many degrees of freedom; operation of mechanisms doesn't satisfy cinematic of rigid body.
Since linearity is lost between linear and angular displacements, between articulate and operational spaces, and between real and amplified representation, it is necessary to apply functions and mapping procedures for relating them. Those mapping errors and their functions are important goals in the field of calibration, where virtual mechanical instrumentation may illuminate cases of controversy. The manuscript treats with several cases of distortion, their possibilities of amplification, their possibilities of assembling, and diagnostic trough inverse kinematics.

Ken Shimojima, Ryoshu Furutani, Kiyoshi Takamasu, Kenji Araki
THE ESTIMATION METHOD OF UNCERTIANTY OF ARTICULATED COORDINATE MEASURING MACHINE

Articulated Coordinate Measuring Machines (A-CMM) are commercial products. However, it is difficult to keep the traceablity of it, because the calibration of A-CMM is performed by the manufacturer’s own method. We planed to use 3D artifact, which had 9 balls for calibration, and test it. The kinematical model of A-CMM was described in D-H notation. In A-CMM measurement, a cone-shaped stylus was used. We measured the artifact in five different locations and orientations. Because the artifact has nine balls, 45 points in total ware measured. the parameters were determined in each location and orientation. Each set of kinematical parameters is applied to the measured points in five different locations and orientations. Then the root mean squares are calculated in 25 kinds of combinations. As a result, the calibration result is better than the specified accuracy of Vectron.

Atsushi Taguchi, Takashi Miyoshi, Yasuhiro Takaya, Satoru Takahashi
HIGH PRECISION INSTRUMENT FOR MICRO SURFACE PROFILE MEASUREMENT BASED ON OPTICAL INVERSE SCATTERING PHASE METHOD

With the advance of microtechnology, inprocess or in situ measurement techniques for measuring surface profiles of engineered micro parts have been increasingly required. We have proposed an optical measurement technique, the optical inverse scattering phase method, which can be applied to the in-process measurement of micro-surface profile with the accuracy in the nanometer order. An instrument has been designed and developed on the basis of the proposed principles, and verified by measuring an ultra precision grid plate having rectangular pockets 44nm deep at intervals of 10µm. The measured surface profile gave good agreement with the nominal dimensions of the specimen as well as the one obtained by AFM.

Kiyoshi Takamasu, Kenichiro Nosaka, Makoto Abbe, Ryoshu Furutani, Shigeo Ozono
ESTIMATION OF UNCERTAINTY FROM UNKNOWN SYSTEMATIC ERRORS IN COORDINATE METROLOGY

In coordinate metrology, a feature (Gaussian associated feature) is calculated from a measured data set by CMM (Coordinate Measuring Machine) using least squares method. This data processing flow is called as "featurebased metrology". In the feature-based metrology, it is a key technique to estimate the uncertainty of measurement in the specific measuring strategy. In this paper, the effects of unknown systematic errors are theoretically analyzed to estimate the uncertainties. The estimation method of uncertainties from two types of unknown systematic errors, such as errors of calibration of ball probe and errors form deviations of measured workpieces, are proposed.

K. T. V. Grattan, J. Skeivalas, V. Giniotis
DEVELOPMENT OF 2D OPTICAL MEASUREMENTS

The analysis of 2D measurement methods and means is presented. The actual optical-electronic devices using bar codes are discussed. The correlation functions of measuring and reference codes in the electronic level instrument are calculated showing possible errors in height determination. The new electronic level design is proposed simplifying the main design and as well as the meter of the level. The principal correlation and error determination equations are given, and the diagrams of the new design are included.

Janos Kundrak, P. Herbert Osanna, Viktoria Bana, Ali Afjehi-Sadat
REALIZATION OF ACCURACY AND QUALITY REQUIREMENTS IN HARD CUTTING

Choosing out of the machining process for the finishing process of machining of the parts requires great attention because by means of that the accuracy and quality requirements prescribed for the parts must be ensured. This paper analysis two processes, the grinding and the hard turning applied for finishing machining of hardened surfaces and presents what kind of accuracy and surface quality parameters for the gears’ hardened surfaces can be ensured with hard cutting.

Ryusuke Nakajima, Takashi Miyoshi, Yasuhiro Takaya, Satoru Takahashi
INTERNAL DEFECT DETECTION IN THE VICINITY OF SI WAFER SURFACE USING EVANESCENT WAVE

In order to reduce and control yield loss in the fabrication process of next generation ULSI devices, nano-defects inspection technique for polished Silicon (Si) wafer surface becomes more essential. This paper discusses the new optical nano-defects detection method, which is applicable to the silicon wafer surface inspection technique for next-generation semiconductors.
In our proposed method, the evanescent light is emerged on the wafer surface with total internal reflection (TIR) of infrared (IR) laser at the Si-air interface. And by scanning the surface where is evanescent light emerging with very shaped fibre probe, it enables to detect nanometre scale defects in the vicinity of Si wafer surface without diffraction limit to resolution. To verify the feasibility of this method, both of the computer simulations based on Maxwell’s equations and the several fundamental experiments are performed. FDTD simulation shows that the proposed method is effective to detect nano-defects existing not only on Si surface but also in the subsurface with high sensitivity. And also the fundamental experiments show the validity of this method by demonstrating nano-defects detections of subsurface as well as surface.

A. Titov, I. Malinovsky, C.A. Massone, M. Kleinke, M.E.R. Dotto
WRINGING DEFORMATION AND ROUGHNESS ASPECTS IN OPTICAL LENGTH MEASUREMENTS

Texture deformations of gauge block surfaces arising in the wringing contact between similar structures have been determined for the first time using atomic force microscopy and optical interferometry. The level of deformations is shown to be dependent on the surface structure, and for modern gauge blocks is about 3 nm, only. Using new parallax-free methods of interferometric length measurements, roughness contribution to the measurement result by optical interferometry have been measured with a few nanometer uncertainty level.

Halina Nieciag, Zbigniew Chuchro
A CERTAIN METHOD FOR CHEBYSHEV APPROXIMATION USED IN IOS METROLOGICAL SOFTWARE

The paper presents a method that is an attempt to solve the problem of non-linear approximation of geometrical elements according to Chebyshev norm. On the base of general two step algorithm it performs an evaluation of minimal deviation from maximal values of measured shapes driving to the optimal solution on the iterative way. The proposed method implemented for some geometric features has been verified for a many samples of simulated and measured datapoints.

Page 895 of 936 Results 8941 - 8950 of 9356