Machinability of Polymeric Composites and Future Reinforcements—A Review

Abstract

This paper reviews the machinability and mechanical properties of natural fiber-reinforced composites. Coupling agents, operating parameters, as well as chemical treatment effects on natural fiber-reinforced composites' machinability are also reviewed. Moreover, the impacts of fibers' physical properties on the machinability of the composite are mentioned. Fiber volume fraction (V f ), fiber orientation as well as chemical treatment effects on mechanical properties are also defined. Conclusively, the effect of fibers' physical properties as well as mechanical properties is described. It was discovered that chemical treatment of natural fibers improved their compatibility with the matrix by removing their surface tissues, increasing the roughness average (Ra), and reducing moisture absorption. Also, the Orientation of the fiber plays an important role in controlling the mechanical properties of the composite. Moreover, some physical properties of the fibers, including quality of fiber distributed in the matrix; fiber size, length, and diameter; moisture absorption; porosity and the way fibers break during compounding with the matrix, were found to affect the mechanical properties of the composites formed.

ANN Based Estimation of the Defects Severity at the Drilling of GFRP/Ti Multilayered Composite Structure

“…High-quality processing of holes in the Carbon/Glass Fiber Reinforced Plastic (CFRP/GFRP) / metal stacks, which are a sequence of alternating layers of composite and metal, is the most difficult, and new varieties of such materials being created require a specific approach to the analysis and development of appropriate technologies. It was experimentally established in [5][6][7][8][9]15,16] that when the cutting edge of the drill moves from the composite to the titanium layer, there is an abrupt increase in temperature, which causes melting of the polymer matrix, as well as a sharp growth in the thrust force , which is most dependent on the feed rate during drilling [3][4][5][6]8,15,17]. The authors of [5,8,15,17,18] also report the occurrence of significant delaminations at the interface between two dissimilar materials.…”

“…It was experimentally established in [5][6][7][8][9]15,16] that when the cutting edge of the drill moves from the composite to the titanium layer, there is an abrupt increase in temperature, which causes melting of the polymer matrix, as well as a sharp growth in the thrust force , which is most dependent on the feed rate during drilling [3][4][5][6]8,15,17]. The authors of [5,8,15,17,18] also report the occurrence of significant delaminations at the interface between two dissimilar materials.…”

“…Their results strongly suggest that delamination is most likely to occur at the points of entry and exit of the drill from the hole being machined. There are also studies aimed at finding a quantitative relationship between the magnitude of unacceptable splintering or fiber breakout, fiber pullout, delaminations, the place of their formation, tool geometry and drilling modes [5,6,8,15]. The monographs [5,6] present the results of the influence of fibers orientation and lay-up sequence on the tendency of the composite to delamination during drilling.…”

“…The experience of machining holes gained in manufacturing has been the source of process improvements such as the use of the back support of the hole to prevent delamination at the drill exit, peck drilling in which drill advances into material, retracts, cools, and cleans chips before repeating the process, and post-drill reaming, in which a reamer removes a layer of material 0.1-0.2 mm thick. To increase the wear resistance of the tool, drills with a cutting part made of hard alloys, diamond or high-speed steel coated with titanium nitride are used [7,15,40,41].…”

“…The described phenomena and problems of implementation of the composites drilling are characterized by the term "machinability", which the author of the article [22] does not consider the exact term even in relation to the drilling of metals. Much more than in the case of metals, the number of factors affect the machinability of layered composites [15], which is usually characterized by the following criteria: 1 -ease of chip removal, 2 -acceptable roughness value, 3 -tool life, 4 -low cutting forces. That is why, although the number of articles published on the machinability of polymer glass fiber and carbon fiber composites until 2020 is about 46,000, a satisfactory model describing the dependence of these criteria on the properties of the material and the parameters of the drilling process has not been developed.…”