Effect of machining parameters on the surface finish of a metal matrix composite under dry cutting conditions

Abstract

The machining of aerospace materials, such as metal matrix composites, introduces an additional challenge compared with traditional machining operations because of the presence of a reinforcement phase (e.g. ceramic particles or whiskers). This reinforcement phase decreases the thermal conductivity of the workpiece, thus, increasing the tool interface temperature and, consequently, reducing the tool life. Determining the optimum machining parameters is vital to maximising tool life and producing parts with the desired quality. By measuring the surface finish, the authors investigated the influence that the three major cutting parameters (cutting speed (50-150 m/min), feed rate (0.10-0.30 mm/rev) and depth of cut (1.0-2.0 mm)) have on tool life. End milling of a boron carbide particle-reinforced aluminium alloy was conducted under dry cutting conditions. The main result showed that contrary to the expectations for traditional machined alloys, the surface finish of the metal matrix composite examined in this work generally improved with increasing feed rate. The resulting surface roughness (arithmetic average) varied between 1.15 and 5.64 mm, with the minimum surface roughness achieved with the machining conditions of a cutting speed of 100 m/min, feed rate of 0.30 mm/rev and depth of cut of 1.0 mm. Another important result was the presence of surface microcracks in all specimens examined by electron microscopy irrespective of the machining condition or surface roughness.

Tool wear and surface quality of metal matrix composites due to machining: A review

“…Effect of other parameter on surface roughness for instance tool vibration or chip adhesion are not considered in the theoretical models. The machined surface integrity of Al/SiCp composite has been studied extensively by experiments (39,(72)(73)(74)(75)(76). There are a vast number of defects on the machined surface, such as voids around the SiC particles, SiC fracture, or cleavage, and cavities due to SiC particle pulled out.…”

“…Moreover, the interaction of the reinforcement particles with the machining operation may explain that the surface roughness of MMCs is larger than that of the base alloy at low feed rates but smaller than that of the base alloy at higher feed rates (39,75).…”

“…The surface finish boron carbide particle-reinforced aluminium MMC at (a) lower feed rate (0.1 mm/rev) and (b) higher feed rate (0.3 mm/rev)(75).…”

Investigation on the material removal and surface roughness in ultraprecision machining of Al/B4C/50p metal matrix composites

“…The MMC machining process and the associated surface roughness, subsurface damage and tool wear have been extensively studied experimentally as well. The optimal machining conditions for particle reinforced MMCs have been the topic of most research recently [12][13][14]. Manna and Bhattacharyya [15] proposed a Taguchi method-based approach in investigating MMCs turning processes which indicates the influence of cutting speed, feed and depth of cut is more or less equal to that on the surface roughness (Ra); depth of cut and feed have more influence on the maximum peak-to-valley roughness height (Rt) comparing to the cutting speed.…”

Effect of Turning Parameters and Reinforcement on the Surface Roughness of Hybrid Aluminium Metal Matrix Composite

“…In the machining of metal matrix composites cemented carbide or PCD inserts are generally used because of their distinct advantages. However, many conflicting studies suggested that the use of carbide inserts is only advantageous if used under certain conditions [16,17]. Researchers concluded that carbide inserts are effective in short run machining operations or roughing operations.…”