Fixtured vibratory finishing of Ti-6Al-4V
Houmayune, Haja Abdul Jaafer.
Date of Issue2013
School of Mechanical and Aerospace Engineering
A*STAR Singapore Institute of Manufacturing Technology
The Ti 6AL-4V alloy accounts for almost 50% of all alloys used in aircraft applications due to its favourable properties. Titanium parts on an aircraft that are subject to fatigue, fracture, or wear can see tangible enhancements in life-span and performance by improving their overall smoothness. Vibratory finishing is a robust mass finishing technique that is widely used for the finishing of Ti parts on aircraft for many decades. However, the process design and optimization is still largely accomplished by experimentation and trial and error with the aim of reducing cycle times and achieving better surface finishes. Fixtured vibratory finishing is employed when part-on-part contact of parts is prohibited and this method has been said to reduce cycle times significantly. However, the extent to which fixture vibratory finishing can reduce processing times and improve surface finish has yet to be studied in detail. The first objective of this project is to build an improved understanding of the process of vibratory finishing and identify the critical process parameters. The second objective is to design, fabricate and assess the effectiveness of a new vibratory finishing fixture on the surface finishing of a Ti-6AL-4V workpiece. The quantification of 2-D and 3-D surface roughness will be carried out using instruments such as a profilometer and a surface topography scanning machine, respectively. The preliminary phase of the study analyses the effects of fixture length, orientation as well as motor revolution speed on the vibrational amplitudes and frequencies of the existing vibratory finishing fixture. Lessons learnt from this analysis will then serve as design inputs for the first phase of the project, which is the design and fabrication of a new vibratory finishing fixture. Phases 2 and 3 will then go on to quantify the vibrational amplitudes and frequencies of the new vibratory finishing fixture, utilizing an accelerometer and high speed camera, respectively. The final phase of the project measures the material removal rate and surface roughness of 5 fixture geometry and input frequency settings. In conclusion, this project serves as a proof of concept that fixtured vibratory finishing reduces process times as well as produce smoother finishes if the fixture is designed such that it has a natural frequency which matches that of the vibratory motor.
Final Year Project (FYP)
Nanyang Technological University