Secondary Machining Characteristics of Additive Manufactured Titanium Alloy Ti-6Al-4V

Titanium alloy, Ti-6Al-4V is a popular alloy used in wide range of design applications mostly in aerospace and biomedical industry due to its advantageous material properties. This research is based on threading operation in a cylindrical workpiece of Ti-6Al-4V additive manufactured by Selective Laser Melting (SLM) technique. Secondary machining is described as the operations that are performed on the workpiece after a primary machining in order to achieve a required finish and form. Common secondary operations after drilling includes threading, reaming and knurling. Threading is a significant machining process in almost all applications of Titanium alloys. The development of an efficient threading process for Titanium alloys and enhancing existing methods may lead to a wider application of additive manufactured Titanium alloys. The aim of this research is to find out favorable threading conditions for Titanium alloy Ti-6Al-4V to obtain better machinability. Threads are tapped into the workpiece using variable machining parameters such as spindle speed and depth of cut. Statistical data are collected and analyzed by qualitative and quantitative evaluation of the threads. The outputs under consideration to evaluate efficiency of the secondary machining include surface texture (roughness (Ra)), dimensional accuracy (thread geometry) and power required (cutting force).