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Ulrich Neuschaefer-Rube, Holger Bremer, Benjamin Hopp, Ralf Christoph
RECENT DEVELOPMENTS OF THE 3D FIBER PROBE

The fiber probe is well known in micro-coordinate metrology. The 2D version has been used for many years to measure injector nozzles, turbine blade cooling holes, and a variety of other small, tight tolerance features. A development of this probe, the 3D fiber probe, has been commercially available for some time.
In a cooperation project, PTB and Werth Messtechnik have continued investigations on this microprobe. This paper reports on the recent achievements. Very small stylus tips with diameters down to 25 µm with isotropic stiffness and novel probe designs are now possible. Dual-sphere and L-shaped styli have opened new applications for holes with large aspect ratios and recessed features. Scanning tests have resulted in form deviations below 0.4 µm.
This paper explains the operating principle, reports on test results and describes some of the applications.

Terutake Hayashi, Yuki Ishizaki, Masaki Michihata, Yasuhiro Takaya, Shin-Ichi Tanaka
STUDY ON NANOPARTICLE SIZING USING FLUORESCENT POLARIZATION METHOD WITH DNA FLUORESCENT PROBE

A fluorescent polarization method is well known for the detection of complementary base pairing of DNA in biological field. The fluorescent polarization method (FP) measures the rotational diffusion coefficient of Brownian motion of the fluorescent particle in the solution. The rotational diffusion coefficient is corresponding to inverse third power of diameter due to the Einstein Stokes Relation for nanoparticle as hard sphere.
We develop a novel rotational diffusion coefficient measurement method by using a fluorescent probe with DNA spacer, which is connected to particle. We investigate the relation between the gold nanoparticle and the fluorescent probe in order to verify the feasibility of the proposed method. The rotational diffusion coefficients of gold nanoparticles, whose diameters are from 5 nm to 20 nm, are evaluated by using the developed system. In this paper we describe the method of fluorescent polarization method by using fluorescent DNA probe (fl-DNA).

Rainer Tutsch, Hanno Dierke
CORRECTION OF SYSTEMATIC ERRORS IN THE STEP-HEIGHT MEASUREMENT WITH OPTICAL SURFACE PROFILERS

Optical instruments are frequently used for surface topography measurement. In general their working principles can be divided into interferometric (e.g. white-light interferometers) and focus sensing (e.g. confocal microscopy) techniques. For both groups a number of systematic error sources are well known. In this paper we will concentrate on step-height measurement and take a closer look at those errors that are caused by the material properties of the workpiece, as there are: material-dependent phase-jumps on reflection, phase- and focus-shift caused by transparent layers and the effects of volume scattering. We describe these effects and give suggestions for procedures to correct these errors. Based on the results of this work the standardization organization DIN in Germany is currently preparing a draft standard DIN 32567.

Kazuhiro Enami
CALIBRATION USING CYLINDRICAL ARTIFACTS FOR LASER 3D MEASUREMENT SYSTEM

We are now developing inner shape measurement system for superconducting accelerator cavities. An acceleration cavity is shaped like bellows which have some cells. Inner shape of a cavity influences accelerating efficiency of particles. To improve and inspect accelerator cavities, we are now developing a system which can measure inner 3D shape. This system scan inner surface by inserting and rotating a laser displacement sensor unit attached to the end of the pole. This system is simple and useful not only for an accelerator cavity but also for a long pipe and a deep hole on an industrial part. We proposed calibration method for such a system. We simulated and analyzed the proposed calibration method and shows availability of cylindrical artifact calibration method.

Gavin MacAulay, Nicola Senin, Claudiu L. Giusca, Richard K. Leach
INVESTIGATION OF MICRO-MANUFACTURING PROCESS PERFORMANCE VIA INNOVATIVE SURFACE CHARACTERISATION METHODS

Increasing interest surrounds micro-manufacturing, in part due to the growth of structured surfaces, which require the fabrication of localised micro-scale surface features. Assessment of manufacturing process performance is critical to optimisation of the resulting product and can be addressed by inspection of the resulting geometries. The micrometre scale of features on typical structured surfaces necessitate the use of optical surface topography measuring instruments, common to surface metrology, to measure such surfaces. However, associated conventional surface texture characterisation methods, based on areal texture parameters, often prove inadequate because they fail to capture the relevant geometric properties needed for an effective dimensional verification. The work reported here investigates an alternative route based on determination of dimensional/geometric attributes of the micro-fabricated features. This approach allows for direct assessment of manufacturing process performance by comparison of the geometric attributes with their nominal values. An example application is shown where a micromachining process (laser texturing) is applied to the fabrication of a periodic pattern of cylindrical pockets (dimples) to be used in low-friction bearing surfaces. Fabrication process performance is assessed through the geometric characterisation of the resulting topographies.

Trung Vuong Pham, Yutaka Ohtake, Yukie Nagai, Hiromasa Suzuki
SHAPE CORRECTION ALGORITHM BY COMPARING SHAPE SILHOUETTE-LINES WITH A SINOGRAM

In industrial X-ray CT application, there is an increasing demand for achieving accurate surface reconstruction of measured objects for dimensional inspection of mechanical parts since the performance of industrial X-ray CT scanners is considerably improved. In this paper, we propose a novel method that reuses X-ray projection images, or a sinogram, to improve the accuracy of the reconstructed surface mesh by correcting the CT values, which is done by fitting silhouette- lines of the mesh to the sinogram. The sinogram is conventionally used only for obtaining a CT volume data, or a tomogram. Since it has become capable to extract the silhouette-lines correctly regardless of beam hardening etc., reusing the sinogram has the potential application for improving the accuracy of the reconstructed mesh.

Ryusuke Sagawa, Tatsuya Kawamura, Ryo Furukawa, Hiroshi Kawasaki, Yoshio Matsumoto
ONE-SHOT 3D RECONSTRUCTION OF MOVING OBJECTS BY PROJECTING WAVE GRID PATTERN WITH DIFFRACTIVE OPTICAL ELEMENT

Recently, the 3D measurement of moving objects becomes an important task in various applications. The potential applications are medical application, multimedia, crash testing, fluid analysis and so on. For these applications, the 3D measurement is required to have properties of high accuracy, high frame-rate, and high density. We have proposed a method based on a projector-camera system that reconstructs a shape from a single image where a static pattern is cast by a projector. The proposed method realizes one-shot 3D reconstruction with a single-colored pattern that consists of vertical and horizontal sinusoidal curves. It finds correspondences in sub-pixel accuracy between projector and camera by using the information implicitly encoded in the grid of wave lines. The reconstructed shape is optimized by interpolating grid patterns to reconstruct dense shape to achieve the above requirements. One of the issues to improve this system is to realize 3D reconstruction under external light that disturbs detection of the pattern. We have developed a laser system to generate the wave grid pattern that can be detected by filtering out external light. The pattern is formed by using diffractive optical element to generate the static pattern power-efficiently without temporal scanning. The power-efficiency can contribute to downsizing of the system. We apply the same approach to reconstruct 3D shapes for medical endoscopy that equips the pattern projector at the tip of the probe. In the experiments, we show the effectiveness of the proposed laser pattern projector by reconstructing 3D shapes.

Eiki Okuyama, Yuichi Suzuki, Masahiro Morikawa, Ichiro Yoshida
SURFACE ROUGHNESS MEASUREMENTS OF A NARROW BOREHOLE - MEASUREMENT OF SURFACE ROUGHNESS STANDARD PIECE

In industrial fields, it is frequently necessary to measure surface roughness in confined spaces such as boreholes and grooves. However, using a small stylus, the surface roughness of a narrow borehole can be directly measured only a few millimeters from its end; alternatively, destructive measurements must be performed. We already proposed a novel surface roughness measurement sensor. To make the surface roughness sensor small, we used a stylus with a cylindrical mirror and a lensed fiber instead of a conventional inductive pick-up. The proposed sensor converts the signal obtained by measuring the surface roughness of a borehole into an optical signal, which is transferred outside the borehole by an optical fiber. Experimental results demonstrate that this system has a measurement range of 8 µ m and a sensitivity of 19 nm. In this paper, a carriage to measure the surface roughness in a small borehole is proposed. The proposed carriage has two degree of freedom, displacement along the borehole axis and rotation around the borehole axis. Furthermore, surface roughness standard pieces were measured by the proposed method and the conventional method. Measurement results obtained by these methods were found to be very similar.

Alexander Schoch, Alessandro Salvadori, Ivo Germann, Silvano Balemi, Carlo Bach, Andrea Ghiotti, Simone Carmignato, Andrea Maurizio, Enrico Savio
FAST MEASUREMENT OF FREEFORM PARTS AT ELEVATED TEMPERATURE USING LASER-TRIANGULATION PRINCIPLE

The increasing quality expectations and the global competition push manufacturing industry to adopt strategies of lean manufacturing and precision engineering. In order to reach these aims it is necessary that the measuring process be integrated in the production chain to provide timely feedback for process control. Nowadays, however, forged products are typically measured after the cool-down process, which can take several hours. The advantages obtainable if forgings would be measured online are clear: deviations in the production process would be recognized earlier and the production process would be promptly adjusted.
On-line measurement capabilities have the potential to reduce overall production costs and consequently are of interest to many forging industries, including those producing complex products such as turbine blades. Under these circumstances, the HOTGAUGE project was initiated: an international EUROSTARS project with the final goal to develop a measuring system, which is capable of measuring freeform shaped parts at elevated temperature (approx. 800 °C) directly after the forging step. The output of the measuring system is a 3D model of the hot part including temperature information.
The 3D measuring apparatus is composed by two main subsystems: a 2D laser-triangulation system capable to scan a complete section of the part, and a moving platform, which transfers the part through the measuring plane.
The architecture and the components of the measurement system as well as preliminary measurement results are presented in this paper.

Hiroyuki Fujimoto
DEVELOPMENT OF DIMENSIONAL X-RAY COMPUTED TOMOGRAPHY

Recently, a dimensional X-ray computed tomography system that is capable of dimensional measurements is strongly waited because the realization of dimensional measurements for outward forms and inward forms on dense spatial points in short time duration remarkably simplifies and accelerates production loop. However the obtained image of the XCT describes the structure clear and in great detail, the realization of the dimensional metrology by the XCT is not simple.
National metrology institute of Japan have been continued the performance test using gauges that includes the gauges proposed in ISO10360. The magnification variation correction is carefully introduced and that the maximum deviation of less than 5 µm is shown to be possible by the measurement of the forest phantom of 27 sapphire balls whose locations are calibrated by the coordinate measuring machine.

Page 390 of 977 Results 3891 - 3900 of 9762