Surface Topography Quantification of Super Hard Abrasive Tools by Laser Scanning Microscopy

Abstract

Non-conventional super hard abrasive tools are made of composite materials containing super hard grains, e.g., diamond or cubic boron nitride (CBN) grains, bound by a metallic constitutive phase. These tools are usually produced by means of sintering, and are widely applied in the abrasive machining processes of modern manufacturing, especially in precision machining. The abrasive grains, which induce the material removal processes, are embedded in the metallic binder. They emerge as a consequence of self-dressing, resulting in a self-sharping effect. Therefore, the cutting surface of the tool displays an irregular topography. Quantification of surface topography scenario may supply valuable information to evaluate and understand its correlation to wear mechanisms. In this study, an experimental protocol consisting of five steps: specimen preparation, surface scanning, image assembly, image digital processing and surface quantification, is proposed and validated by characterizing two CBN honing tools used for precision machining: B151/L2/10/50 (B151) and B91/128/x44/35 (B91) CBN honing stones. It involves the use of laser scanning microscopy and digital imaging processing for assessing significant dimensional, geometrical and positional properties of CBN grains at the surface of super hard abrasive tools. It is shown that surface topography quantification is an effective method to evaluate and obtain the defined parameters. However, smaller grains may require images with higher resolution; and thus, scanning must be refined. Finally, a critical comparative analysis of the experimental results attained for the studied tools points out honing stone B91 as more appropriated than B151 one for achieving a higher machining quality of the workpiece.

3D characterization of cubic boron nitride (CBN) composites used as tool material for high precision abrasive machining processes

“…Then, a larger quantity of CBN grains in the honing stone B151 is involved in the investigation and more satisfactory and reliable results are obtained from a statistical point of view. For instance, the obtained mean grain size of D eq is 132 µm in the 3D volume quantification, which is much closer to the nominal one of 138 µm compared to that of 123 µm obtained in the 2D surface quantification [7].…”

“…Hence, the surface topography becomes relevant for correlating tool material characteristics and its performance. In a recent work by the authors, a two-dimensional (2D) quantification protocol has been proposed for assessing the geometrical properties of CBN grains on the cutting surfaces of a honing stone [7].…”

Laser surface texturing of a WC-CoNi cemented carbide grade: Surface topography design for honing application

“…In a recent work, authors have provided a detailed quantitative characterization of surface topography of a conventional honing stone, tagged as B151, which will be used here as reference condition [26].…”

The relation between the geometric parameters of grinding powders grains measured by laser diffraction and light-microscopical methods

“…The pressing issue of abrasive processing is the study of the geometric parameters of grinding powders grains. They affect the cutting ability and wear resistance of the abrasive tool, the force and temperature of cutting and the quality of the treated surface [1][2][3].…”