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1.
A new method for estimating the Hurst exponent H for 3D objects
Matej Babič, Peter Kokol, Nikola Guid, Peter Panjan, 2014, original scientific article

Abstract: Mathematics and computer science are very useful in many other sciences. We use a mathematical method, fractal geometry, in engineering, specifically in laser techniques. Characterization of the surface and the interfacial morphology of robot-laser-hardened material is crucial to understand its properties. The surface microstructure of robot-laser-hardened material is rough. We aimed to estimate its surface roughness using the Hurst parameter H, which is directly related to the fractal dimension. We researched how the parameters of the robot-laser cell impact on the surface roughness of the hardened specimen. The Hurst exponent is understood as the correlation between the random steps X1 and X2, which are followed by time for the time difference t. In our research we understood the Hurst exponent H to be the correlation between the random steps X1 and X2, which are followed by the space for the space difference d. We also have a space component. We made test patterns of a standard label on the point robot-laser-hardened materials of DIN standard GGG 60, GGG 60 L, GGG 70, GGG 70 L and 1.7225. We wanted to know how the temperature of point robot-laser hardening impacts on the surface roughness. We developed a new method to estimate the Hurst exponent H of a 3D-object. This method we use to calculate the fractal dimension of a 3D-object with the equation D = 3 - H.
Keywords: fractal structure, Hurst exponent, robot, hardening, laser
Published in DKUM: 14.03.2017; Views: 1679; Downloads: 153
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2.
Problems associated with a robot laser cell used for hardening
Matej Babič, Matjaž Milfelner, Igor Belič, Peter Kokol, 2013, original scientific article

Abstract: Laser hardening is a surface-hardening process. It is used exclusively on ferrous materials suitable for hardening, including steel and cast iron with acarbon content of more than 0.2 %. This article describes robot laser hardening, the results of previous work, research and experience with robot laser hardening. The second part of the paper describes the problems associated with robot laser hardening at different angles. We wanted to find the impact of the angles on the hardness of the material. Therefore, we directed the laser beam at different angles, including perpendicular, in the process of hardening. We made test patterns of a standard label on the materials of DIN standard 1.2379.
Keywords: hardening, robot, laser, parameters, hardening, robot laser, parameters
Published in DKUM: 10.07.2015; Views: 1852; Downloads: 114
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