Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/16491
Title: MICRO-EDM-BASED MULTI-PROCESS MACHINING OF TUNGSTEN CARBIDE
Authors: MUHAMMAD PERVEJ JAHAN
Keywords: Micro-EDM, Multi-process machining, Tungsten carbide, Vibration-assisted micro-EDM, Fine-finish micro-EDM, Powder-mixed micro-EDM
Issue Date: 31-Jul-2009
Source: MUHAMMAD PERVEJ JAHAN (2009-07-31). MICRO-EDM-BASED MULTI-PROCESS MACHINING OF TUNGSTEN CARBIDE. ScholarBank@NUS Repository.
Abstract: This study aims to develop micro-EDM-based multi-processes for the machining of difficult-to-cut tungsten carbide (WC). In the first phase of this study, investigation has been carried out on the machinability of WC in micro-EDM and improvement of the micro-EDM system by comparing the performance of existing transistor-type pulse generator with the newly developed RC-type pulse generator It is found that WC has better machinability in micro-EDM and RC-type pulse generator is more suitable for fabricating micro-structures in WC.In the second phase, a low-frequency vibration device has been developed and both analytical and experimental investigations have been carried out on the mechanism and performance of vibration-assisted micro-EDM for deep-hole drilling in WC. A significant improvement in the machining performance as well as quality, accuracy and aspect ratio of micro-holes was observed. In addition, high-aspect-ratio microelectrodes were fabricated on-machine using Turning-B5EDM hybrid process and Block-B5EDM process to apply in deep-hole drilling of WC using vibration-assisted micro-EDM.In the last phase, investigation has been carried out to improve the quality and integrity of the surface finish of WC using newly developed milling micro-EDM and nanopowder mixed dielectric. An analytical and experimental investigation has also been carried out on powder-mixed micro-EDM of WC. It is found that milling micro-EDM provides smoother and defect free nanosurfaces with higher MRR and lower EWR compared to conventional sinking micro-EDM. Moreover, powder mixed micro-EDM with conductive or semi-conductive particles in the dielectric can enhance the surface finish to a great extent in addition to improving the overall performance. Finally, the integration of multiple processes with micro-EDM has greatly enhanced the performance by minimizing the problems with performance issues of micro-EDM alone.
URI: http://scholarbank.nus.edu.sg/handle/10635/16491
Appears in Collections:Ph.D Theses (Open)

Show full item record
Files in This Item:
File Description SizeFormatAccess SettingsVersion 
PhD Thesis_Muhammad Pervej Jahan.pdf9.83 MBAdobe PDF

OPEN

NoneView/Download

Page view(s)

605
checked on Dec 11, 2017

Download(s)

1,013
checked on Dec 11, 2017

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.