Optimization and Influence of Process Parameters on Surface Roughness in Turning of Titanium Alloy under Different Lubricant Conditions

Abstract

In any machining process, large amount of heat is generated due to plastic deformation of work material, friction at the tool – chip and tool - work piece interface. In dry machining, the heat generated adversely affects the quality of the products. Therefore, effective control of heat generated in the cutting zone is essential to ensure good surface quality of the work piece in machining. Cutting fluids have been the conventional choice to deal with this problem. Cutting fluids are introduced in the machining zone to improve the tribological characteristics of machining processes and to dissipate the heat generated. The advantages of cutting fluids however been questioned later on due to the negative effects on product cost, environment and human health. Later on Minimum Quantity Lubrication (MQL) has been tried as a possible alternative to the use of flooded coolants. Minimum Quantity Lubrication machining refers to the use of a small amount of cutting fluid, typically in order of 300 ml/hr or less, which are about three to four orders of magnitudes lower than that used in flooded lubricating conditions.This paper deals with the optimization and influence of process parameters on surface roughness in turning of Ti-6Al-4V alloy under dry, flooded and Minimum Quantity Lubrication (MQL) conditions using Taguchi’s robust design methodology. The results have been compared among dry, flooded and MQL conditions and it reveals that MQL shows better performance and improvement in reduction of surface roughness as compared to dry and flooded lubricant conditions. The CVD coated tool shows better performance as compared to the uncoated and PVD coated tools. It is also observed from the ANOVA that, feed rate has major influence on surface roughness.