Surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (WEDM) / Nornisaadila Musa

The high demand of Ti-6Al-4V in medical industries becoming a concern nowadays. Titanium is a suitable material for orthopedic implants, dentistry and cardiovascular aids due to high resistance, immunity to corrosion, high fracture strength, osseointegration, low modulus and density. As the titan...

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Main Author:	Musa, Nornisaadila
Format:	Thesis
Language:	English
Published:	2020
Subjects:	Atomic physics Constitution and properties of matter
Online Access:	https://ir.uitm.edu.my/id/eprint/54136/1/54136.pdf
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spelling	my-uitm-ir.541362022-05-19T14:16:55Z Surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (WEDM) / Nornisaadila Musa 2020-05 Musa, Nornisaadila Atomic physics. Constitution and properties of matter The high demand of Ti-6Al-4V in medical industries becoming a concern nowadays. Titanium is a suitable material for orthopedic implants, dentistry and cardiovascular aids due to high resistance, immunity to corrosion, high fracture strength, osseointegration, low modulus and density. As the titanium is one of the most expensive materials and is categorised as a difficult-to-machine material, it is governed by the limitation of being machined through conventional machining. Hence, the problem in machining titanium can be solved by an alternative non-conventional machining process. A wire electro-discharge machining (WEDM) is able to machine the electrically conductive materials and with no physical contact between the workpiece and wire electrode which aids in keeping the material non-toxic for medical applications. The toxicity of the material has to be tested by way of biocompatibility testing. This research aims to develop the machining WEDM surface roughness prediction model through Artificial Neural Network (ANN), to characterise the machined surface of Ti-6Al-4V through WEDM and to determine the influences of machining processes on the biocompatibility of the machined part. The preliminary WEDM cutting operation helps in identifying the parameters and levels for the actual WEDM process. There are five phases in investigating the WEDM process of Ti-6Al- 4V. Phase I is preliminary WEDM cutting operation, Phase II is mathematical prediction modelling on surface roughness by ANN, Phase III is sample preparation, Phase IV is machined surface observation and Phase V is cytotoxicity testing. In this study, three parameters which are pulse-off time, peak current and wire tension applied to WEDM process to achieve desired output performance. The experimental surface roughness is compared with predicted surface roughness using the Artificial Neural Network to optimise combination of parameters. It is found that, the lowest surface roughness (1.3770 μm) with minimum error percentage 0.5434 % obtained by the best combined parameters; 2 μs pulse-off time, 12 N wire tension and 10 A peak current. The pulse-off time is less significant on surface roughness observation. The effect of the machining process that is observed are the surface roughness, surface topography, elementary analysis and microhardness. The thickness of the white layer depends on the discharge energies at the gap between the wire electrode and the workpiece. The elements of Ti-6Al-4V maintained after the machining process. There are existence of zinc, carbon and oxygen that migrates from the workpiece and deionized water. The microhardness increased below the surface as the machined surface experiences thermal softening due to high temperatures. The biocompatibility of Ti-6Al-4V with L929 cells is based on the cell culture and cell viability testing showed 80% positive cell viability for each concentration of Ti-6Al-4V medium. 2020-05 Thesis https://ir.uitm.edu.my/id/eprint/54136/ https://ir.uitm.edu.my/id/eprint/54136/1/54136.pdf text en public masters Universiti Teknologi MARA Faculty of Mechanical Engineering Saedon, Juri (Dr.)
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
advisor	Saedon, Juri (Dr.)
topic	Atomic physics Constitution and properties of matter
spellingShingle	Atomic physics Constitution and properties of matter Musa, Nornisaadila Surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (WEDM) / Nornisaadila Musa
description	The high demand of Ti-6Al-4V in medical industries becoming a concern nowadays. Titanium is a suitable material for orthopedic implants, dentistry and cardiovascular aids due to high resistance, immunity to corrosion, high fracture strength, osseointegration, low modulus and density. As the titanium is one of the most expensive materials and is categorised as a difficult-to-machine material, it is governed by the limitation of being machined through conventional machining. Hence, the problem in machining titanium can be solved by an alternative non-conventional machining process. A wire electro-discharge machining (WEDM) is able to machine the electrically conductive materials and with no physical contact between the workpiece and wire electrode which aids in keeping the material non-toxic for medical applications. The toxicity of the material has to be tested by way of biocompatibility testing. This research aims to develop the machining WEDM surface roughness prediction model through Artificial Neural Network (ANN), to characterise the machined surface of Ti-6Al-4V through WEDM and to determine the influences of machining processes on the biocompatibility of the machined part. The preliminary WEDM cutting operation helps in identifying the parameters and levels for the actual WEDM process. There are five phases in investigating the WEDM process of Ti-6Al- 4V. Phase I is preliminary WEDM cutting operation, Phase II is mathematical prediction modelling on surface roughness by ANN, Phase III is sample preparation, Phase IV is machined surface observation and Phase V is cytotoxicity testing. In this study, three parameters which are pulse-off time, peak current and wire tension applied to WEDM process to achieve desired output performance. The experimental surface roughness is compared with predicted surface roughness using the Artificial Neural Network to optimise combination of parameters. It is found that, the lowest surface roughness (1.3770 μm) with minimum error percentage 0.5434 % obtained by the best combined parameters; 2 μs pulse-off time, 12 N wire tension and 10 A peak current. The pulse-off time is less significant on surface roughness observation. The effect of the machining process that is observed are the surface roughness, surface topography, elementary analysis and microhardness. The thickness of the white layer depends on the discharge energies at the gap between the wire electrode and the workpiece. The elements of Ti-6Al-4V maintained after the machining process. There are existence of zinc, carbon and oxygen that migrates from the workpiece and deionized water. The microhardness increased below the surface as the machined surface experiences thermal softening due to high temperatures. The biocompatibility of Ti-6Al-4V with L929 cells is based on the cell culture and cell viability testing showed 80% positive cell viability for each concentration of Ti-6Al-4V medium.
format	Thesis
qualification_level	Master's degree
author	Musa, Nornisaadila
author_facet	Musa, Nornisaadila
author_sort	Musa, Nornisaadila
title	Surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (WEDM) / Nornisaadila Musa
title_short	Surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (WEDM) / Nornisaadila Musa
title_full	Surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (WEDM) / Nornisaadila Musa
title_fullStr	Surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (WEDM) / Nornisaadila Musa
title_full_unstemmed	Surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (WEDM) / Nornisaadila Musa
title_sort	surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (wedm) / nornisaadila musa
granting_institution	Universiti Teknologi MARA
granting_department	Faculty of Mechanical Engineering
publishDate	2020
url	https://ir.uitm.edu.my/id/eprint/54136/1/54136.pdf
_version_	1783734885709512704

Surface analysis and biocompatibility of titanium alloy after wire electro-discharge machining (WEDM) / Nornisaadila Musa

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