Investigation on machinability of aluminum 7075 under dry environment

Abstract

Aluminum is a light and soft material that is difficult to machine. It is the most produced non-ferrous metal and undergoes extensive machining for the development of a wide range of products. Advances in industry inspire the need to find sustainable ways of machining aluminum and its alloys using conventional machining processes. In the study reported in this paper, two sets of experiments were conducted to investigate the machinability of aluminum 7075 using a plain carbide tool under a dry environment, i.e., no lubrication. In the first set, four rough experiments were conducted where three important machining parameters, i.e., cutting speed CS (115-495 RPM), depth of cut DOC (0.8-1.5 mm), and Feed rate FR (0.08-0.2 mm/rev) have been varied at two levels each to check the behavior of responses or machinability indicators, i.e., surface roughness and tool wear, at machining parameters' highest and lowest values. Based on the results of the first set of experiments, the ranges and levels of parameters have been fixed in the second set for a detailed study of the machinability of aluminum. A total of nine experiments based upon Taguchi's robust design of experiment technique with orthogonal array L9 have been conducted where an additional machining parameter, i.e., machining time MT, has been introduced. The effect of machining parameters on tool wear and surface roughness has been studied in detail, and it is found that the dry machining of aluminum is possible without the early failure of the tool. Dry machining with low values of CS, DOC, FR, and medium MT is desirable for better machinability, i.e., minimum roughness and tool wear, an optimum combination of machining parameter cutting speed-115 RPM, depth of cut-0.8 mm, feed rate-0.12 mm/rev, and machining time-90 seconds. The findings of the present work will assist engineers and researchers in attaining quality, productivity, and sustainability while manufacturing parts and components from aluminum to be used in the automotive, defense, and aerospace sectors.

Keywords

• aluminum
• chip
• dry cutting
• machinability
• tool wear
• surface quality