Characteristics of dimple structure on aluminium silicon alloy fabricated using turning machine

Abstract

Purpose This research aims to present the characteristics of dimple structure which was fabricated using a turning machine, where the characteristics include sizes, shapes, area ratio and aspect ratio. This research aims at filling the gap in the machining parameters of previous research in producing dimple by using turning process with the aid of dynamic assisted tooling for turning (DATT). In producing dimple, a carbide insert grade H1 was used on a hypereutectic aluminium silicon alloy (A390) material. Dimple has many advantages such as for reducing friction coefficient, load-carrying capacity and trap wear debris for sliding mechanical components. Design/methodology/approach There are seven machining parameters (cutting speed, feed rate, depth of cut, frequency, amplitude, rake angle, relief angle and nose radius) which have an influence on dimple produced. Taguchi method (orthogonal arrays L8) was used to conduct the experiment systematically and efficiently for these seven parameters. A carbide insert grade H1 was used as a cutting tool on a turning machine with the aid of DATT. The dimple structure was fabricated on a cylindrical rod hypereutectic aluminium silicon alloy (A390). A profilometer 3D Alicona infinite focus and an optical microscope equipped with Vis software were used to analyse the fabricated dimple structure. Findings Various shapes and sizes of ellipse dimples were produced in this research, including short and long drops with lengths in the range of 517.03–3,927.61 µm, widths of 565.15–1,039.19 µm, depths of 14.46–124.87 µm, area ratios of 5.05–25.65% and aspect ratios of 0.007%–0.111%. There were four experiments within the optimal area ratio range of 10%–20%, i.e. the second, third, seventh and eighth experiments. The width of these dimples was 895.95, 961.39, 787.27 and 829.22 µm, length was 826.26, 3163.13, 885.98 and 1026.65 µm, depth was 83.67, 84.19, 87.05 and 110.70 µm and area ratio was 15.12%, 13.14%, 14.79% and 12.70%. The surface roughness of textured surface was below 1 µm. In this research, the results obtained were similar with that of previous researchers on dimple structure related to tribology performance. Originality/value There exists machining parameters, namely, cutting speed and frequency, that were not used by previous research in producing dimple. These machining parameters (cutting speed and frequency) were used in this research to produce dimple via turning process with the aid of DATT using carbide insert grade H1. The turning process is an environmentally friendly process which is suitable for mass production for fabricating dimple structure as compared to most of the current methods which are widely used in fabricating dimple structure.

Hydrodynamic performance study of a dimple textured surface at various area ratios and sliding speeds using CFD

“…Larger clearance is presented at the higher-pressure side, while smaller clearance faces the lower pressure side, causing impedance in the flow, thus enhancing the load-carrying capacity. Recent study by Nasir et al 49 showed various shapes and sizes of ellipse dimples dimple that can reduce the friction were fabricated using turning process which is environmentally friendly and suitable for mass production.…”