Michal Wieczorowski, Leszek Rozanski
ROUGHNESS ASPECTS IN THERMAL ANALYSIS OF MACHINE TOOLS

In the paper analysis of surface topography influence on emissivity of metals was shown. This was performed for infrared band comprising wavelength region of 7.5 – 13 micrometers. Appropriate characterization and description of object emissivity has a crucial influence on accuracy of IR system for remote temperature measurement, e.g. IR thermography or pyrometry. These properties depend on many factors, including surface topography of material, where especially cavities play a very important role. In references so far emissivity are discussed mainly as influence of type of material (metal, dielectric), its temperature, wavelength or direction of emission. In the paper characterizing emissivity of construction materials in connection with 3D surface topography.

N. Arunachalam, B. Ramamoorthy
VISION BASED SURFACE ROUGHNESS EVALUATION OF GROUND COMPONENTS USING WAVELET TRANSFORM AND NEURAL NETWORK

This paper describes a non-contact technique to assess the differences in surface characteristics of the ground components. The computer vision based system is used to analyze the pattern of scattered light from the surface to asses the surface roughness of the component. The ground specimens were manufactured using varying machining parameters. The images of the specimens are captured using a CCD camera. The image parameters based on the wavelet transform are evaluated. Then, the evaluated parameters along with the cutting parameters were used to train the artificial neural network to predict the surface roughness parameters R_a, which is measured using the stylus instrument. The comparison of stylus R_a and that predicted using ANN are presented and analyzed in this paper.

Daniel Hamburg-Piekar, Gustavo Daniel Donatelli
A HYBRID APPROACH TO THE UNCERTAINTY ANALYSIS OF COORDINATE MEASUREMENTS

In this paper, a new methodology for the uncertainty analysis of coordinate measurements is presented. The methodology can be applied on any kind of measurements performed by a CMM, and it is intended to be especially useful when performing reference measurements of geometrical and dimensional characteristics of workpieces. Master parts calibrated using this approach can be used in connection with ISO/TS 15530-3 for the uncertainty assessment of other CMMs, when measuring similar parts. Consistent measurement strategies and the real measurand definition according to the technical drawing are the foundations of this methodology, generally based in high-density measurement points. Assessment of uncertainties is performed using models in complete agreement with the measurement procedure, considering all major uncertainty contributions. Resources from artificial intelligence were applied to accelerate the development of adequate measurement procedures, simplifying the work of the CMM operator. To validate the proposed methodology, a cast iron steering case was calibrated and compared to simulation results obtained with PUNDIT/CMM, a software solution for task-specific uncertainty evaluation of coordinate measurements.

Cristiana Zanatta Viana, André Roberto de Sousa, Anésio Mariano Junior
STANDARDIZATION OF MEASUREMENT STRATEGIES IN COORDINATE METROLOGY IN THE AUTOMOTIVE SUPPLY CHAIN

The outsourcing in the automotive industry transferred the responsibility to produce products with quality to its supplier and, consequently, the definition and execution of the measurements in the supplied products. However, it is still frequent the occurrence of the conflicts between companies related to divergences in the dimensional tests. This problem is more critical in coordinate metrology, due to the many parameters in the measurement process. This paper describes a methodology developed for the standardization of measurement strategies to be used during the product development and its application in the supply chain of the Brazilian automotive industry.

P. Fernández, B.J. Álvarez, J.C. Rico, D. Blanco, G. Valiño
SCANNING OF FREE-FORM SURFACES BY USING A LASER-STRIPE SENSOR ON A CMM

This research presents a working methodology for developing an automatic planning system of the scanning process of free-form surfaces. The surface has been modelled using a STL format, that permits the automatic recognizing of any type of surface. This work does only consider collision-free orientations that guarantee the visibility of the zone to scan and that are compatible with the constraints imposed by the process parameters. To speed up the calculation of these orientations, different methods like back-face culling and space partitioning techniques, such as kd-trees, are applied. Once the space occupied by the part is partitioned in regions, recursive ray traversal algorithms are used in order to check for intersection exclusively the part triangles (STL) that can potentially be traversed by each laser beam direction.