Electrostatic Charges of Abrasive Powders: A Role of Particle Size and Humidity

Electrostatically coated abrasives have drawn vast attention in many industrial applications. Therefore, influence of humidity on the electrical properties of α-SiC and α-Al2O3 abrasive powders with three μm-range particle sizes are here investigated using electrostatic charge and DC resistivity analysis. From the three particle size ranges used, 15–16 μm, 60–63 μm and 153–156 μm, the intermediate one (60–63 μm) is found to be associated with the highest charge values, measured using a double Faraday cup method, as well as the highest resistivity for both materials. However, comparing SiC and Al2O3 powders, the latter ones present about twice larger charges in dry and normal humidity states accompanied by several orders of magnitude larger resistivity. Under humid conditions all the powders reveal diminishing charge and resistivity values.

A Method for Tribological Measurements of Coated Abrasives using a Rheometer

Coated abrasives (sandpaper) are imperative in various industrial areas, including the automotive and the metal industry. An exact outcome is often highly appreciated in abrasion processes, which means that the wear process must be precisely controlled. In this paper, a new method for analyzing the grinding process of coated abrasives is proposed. In order to study the grinding properties of sandpaper, a tribology cell was connected to a rheometer. The experiments consisted of unlubricated (dry) steel balls-on-disc experiments on coated abrasive with aluminum oxide grains. The friction and wear data showed that the rheometer equipped with a tribology cell can be used to measure different tribological parameters, such as the friction coefficient and the Gap. The wear process was investigated over a range of abrasive grain sizes (9–40 µm) and a variety of different loads (1–10 N). Results from these experiments showed that the abrasive wear increased with increasing particle size and normal load. Hence, it is proposed that this method is a reliable approach for investigating the wear process of coated abrasives.

Development of a Technique for the Study of the Coated Abrasive Surface Wear

Wear of abrasive tools, including coated abrasives, is an important performance feature. A large number of theoretical works and practical studies are devoted to wear assessment issues. In practice, there are many direct and indirect approaches to measuring wear of an abrasive tool. At the same time, many of them have significant shortcomings such as assessment complexity, high time costs, a significant share of manual labor, low measurement accuracy, the need to use specialized equipment, etc. Based on the foregoing, the development of an effective technique for assessing the coated abrasive wear with the use of information and analytical technologies is very relevant and promising. This work is devoted to the development of an original technique for determining the wear of coated abrasives and studying of the tool surface texture. Some results of studies on the wear of coated abrasives of various grain sizes and manufacturers are presented in the article.