Analysis of the fractional composition of the dust of the working area when drilling composite materials based on carbon fibers

Abstract

Modern production of unmanned aerial vehicles is characterized by the use of high-tech materials based on carbon fibers, the assembly operations of which are characterized by a large number of mechanical drilling operations, which are performed mainly by hand using a carbide tool with a diamond coating. The paper presents a study of the concentrations and dispersion of the dust composition and the geometric shape of the dust-forming particles in the working space of workers of machining shops during the technological operations of drilling, milling and countersinking of packages of composite materials based on carbon polyacrylonitrile fibers. On the basis of the conducted experiments, the regularities of the distribution of dust of different fractions in the horizontal and vertical planes of the working space at a distance covering the zone of the immediate location of the worker during this type of operation were determined. The obtained data made it possible to record a significant excess of the maximum allowable concentrations of finely dispersed residues of polyacrylonitrile fibers in the working area of the drill, 2.5 and 10 μm in size and elements of the carbon matrix. In order to investigate the possibility of a negative impact of the dust of the working area on the body of the worker, a study of the fractionation and geometric shape of carbon fiber fragments was performed using raster microscopy, based on which it was concluded that the fiber fragments have a spear-shaped, pointed shape, and the carbon matrix forms conglomerates, which are characterized sharp edges and can cause significant damage when they affect the human respiratory system. On the basis of the obtained results, recommendations were given in the work to improve the indicators of the dust load of workers to normalized values with the help of the use of special suction devices and personal protective equipment with special filters.