Roshaliza Hamidon
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Preferred name
Roshaliza Hamidon
Official Name
Roshaliza, Hamidon
Alternative Name
Hamidon, Roshaliza
Hamidon, R.
Main Affiliation
Scopus Author ID
54941292900
Researcher ID
ICQ-9949-2023

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Surface roughness analysis of NiTi alloy in electrical discharge coating process

2020-12-18 , Jamaluddin Roshalliza , Tan Chye Lih , Ahmad Fairuz Mansor , Azwan Iskandar Azmi , Roshaliza Hamidon

Nickel-Titanium (NiTi) alloys, most widely known as nitinol, are presently employed in many micro-engineering applications such as coronary stents of medical implants due to their unique properties (shape memory effect and superelasticity). However, non-optimized surface finishing attributed a significantly high potential of nickel exposure after a long time of application. Releasing of nickel ion to the body environment can be harmful and toxicity resulting in adverse health as well as degrading the material biocompatibility. It is widely known that controlled surface roughness play a vital role in the formation of new bone ingrowths around implant. In this study, surface modification of NiTi alloy was used through electrical discharge coating (EDC); an adaptation of electrical discharge machining. The potential of EDC in which can facilitates the production of hard coatings may exploit the phenomena for the attachment of desirable materials onto the surface of materials. Therefore, the aim of this paper is to present a robust method (two levels of full factorial design and ANOVA) to determine the desired parameters and significant factors based on the surface roughness of the machined surface. Manipulation of parameters set up such as gap voltage, discharge duration and pulse interval and the current were employed and a reverse polarity was selected for this experiment. The results demonstrated that the most significant factors influence the surface coating performances are the discharge duration, current, gap voltage as well as the interaction between gap voltage and discharge duration.

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Machining of Cobalt Chromium Molybdenum (CoCrMo) Alloys: A Review

2021-01-01 , Saravanan R. , Roshaliza Hamidon , Murad N.M. , Zailani Zainal Abidin

Cobalt chromium molybdenum (CoCrMo) alloys are not only broadly applied in engineering fields but also in manufacturing of surgical implants components and medical devices due to its outstanding properties of wear resistance and great biocompatibility as demanding in the vivo environment. However, these alloys classified as difficult to cut materials as it presents several characteristics such as high hardness, low thermal conductivity, high wear resistance and strain hardening which contribute to its poor machinability. Although these CoCrMo alloys are theoretically similar to titanium alloy in terms of properties but the studies on machining of CoCrMo alloys still insufficient. This paper provides a review on machining aspects of cobalt chromium molybdenum (CoCrMo) alloys including the properties and machinability, cutting fluid methods and tool material selection for these alloys.

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Machinability of Nickel Titanium Shape Memory Alloys: A Review

2021-01-01 , Noor N.Z.M. , Zailani Zainal Abidin , Roshaliza Hamidon , Norshah Aizat Shuaib

Shape memory alloys of Nickel Titanium (NiTi) reveal a reversible diffusionless transition between phases, resulting in unique properties and applications. It is widely used in varieties of products; especially in aerospace and medical fields. Yet, these alloys known as hard-to-machine materials owing to their properties of unconventional stress-strain behaviour, high work strain hardening and high ductility. That’s why their machinability is a major issue. The common drawbacks are serious burr formation, rapid tool wear, poor surface quality and high cutting force. This paper puts forward any possibilities to enhance the machining performance through paper reviews from previous researchers. A notable finding is that the machinability issues can be reduced or lessened by changing the cutting parameters and cutting conditions in order to improve the machinability of NiTi alloys.

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Effect of Inclined Angle in Trimming of Ultra-high Strength Steel Sheets Having Inclined and Curved Shapes

2023-11-01 , Leong K.Y. , Muhammad Hasnulhadi Mohammad Jaafar , Nur Liyana Tajul Lile , Zailani Zainal Abidin , Mohd Zamzuri Mohammad Zain , Roshaliza Hamidon

Trimming the scrap portion of ultra-high strength steel (UHSS) components poses a significant challenge due to the inherent high strength and hardness characteristics of the material. For UHSS components with a higher geometric complexity such consisting of inclined and curved sections, sharp tilt, and small bend radius, the large trimming load results in poor sheared quality and shape defects, which commonly happen in these areas. This research investigated the effects of applying a small inclination angle to the punch in the trimming of the UHSS parts having an inclined and curved shape. The inclined punch was modified to four sets of different degrees of inclination i.e., 1°, 3°, 5°, and 10°. A comparative analysis of the trimming load, trimming energy, sheared edge quality and shape defects was conducted between these modified punches and the normal punch for their effectiveness in the trimming operation. Results showed that the application of inclination angle significantly decreased the trimming load, reduced the trimming energy, and improved the sheared edge surface quality, as well as prevented the shape defects at the inclined and curved zones as compared to the outcomes produced when trimming using the normal punch. The study suggested that the change to the punch geometry is an effective option to improve the performance of the process as well as the quality of the part, particularly in trimming the high-strength components having complex shapes.

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Improvement on the Surface Quality in Machining of Aluminum Alloy Involving Boron Nitride Nanoparticles

2021-01-01 , Zailani Zainal Abidin , Zaibi N.M. , Roshaliza Hamidon , Harun A. , Muhammad Syahril Bahari , Zakaria S.

Aluminum Alloys are used in a variety of applications due to their lightweight, strength-to-weight ratio and relatively ease of fabrication. In aerospace industry, millions of holes drilled annually on airframe structures. Normally, cutting fluids have been used to help reduce friction and heat. However, the use of cutting fluid is one of the major concerns when considering the environmental issues in machining. The disposal of used cutting fluid poses problems to the environment. This research investigates the effect of greener technique; hexagonal Boron Nitride nanoparticles dispersed in oil as compared to dry cutting and oil alone in through hole drilling operation Their impact on tool wear, surface roughness, and holes quality in terms of diameter accuracy, circularity and cylindricity were experimentally studied. Results showed that application of hexagonal Boron Nitride improved surface finish and produced better dimensional hole accuracy. The work clearly shows the important of nanoparticles in improving machinability of this material.

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Effect of Different Cutting Conditions on Tool Wear and Chip Formation in Drilling of Cobalt Chromium Molybdenum

2021-01-01 , Roshaliza Hamidon , Zulkefli N.A. , Saravanan R. , Zailani Zainal Abidin , Muhammad Syahril Bahari , Zakaria S. , Azmi Harun

Cobalt-Chromium Molybdenum (CoCrMo) alloy is categorized under hard to cut material due to its unique combination characteristics such as high strength and low thermal conductivity. However, there was a problem during machining hard alloy material which is rapid tool wear. The tool wear will cause changes at tooltip geometry consequently has significant influence on the chip forming. There are some factors that influence tool wear which are cutting parameters, type of drill bit, and cutting fluids. In this study, a series of experiment were conducted to investigate the effect of cooling conditions on tool wear and chip formation during drilling this material. The cooling conditions used were dry, pure Karanja oil (MQL condition), and combination of Hexagonal boron nitride (hBN) nanoparticles with Karanja oil (MQL condition). The experiment was conducted under constant cutting speed of 20 m/min, and feed rate of 0.07 mm/rev through holes. Each hole was inspected when the tool wear reached 0.3 mm. The result showed that mixed of hBN with Karanja Oil (MQL condition) had lowest growth of flank wear and produced more holes compared to dry and pure Karanja oil condition. In addition, for chip formation, the size of lamellae produced was finest compared to other conditions.

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Electrical discharge coating of NiTi alloy in deionized water

2021-01-01 , Jamaluddin R. , Tan Chye Lih , Roshaliza Hamidon , Ahmad Fairuz Mansor , Azwan Iskandar Azmi

Shape memory alloys, specifically nickel-titanium (NiTi), exhibit excellent technical properties that suited them for biomedical applications. However, the release of nickel ions into human body is a drawback because it results in severe adverse health effects as well as degrades the biocompatibility of the alloys. In this work, surface modification through adaptation of electrical discharge machining was used to develop a deposition layer of titanium oxide on NiTi alloy surface. The adaptation was through electrical discharge coatings (EDC) parameters such as polarity, gap voltage, and erosion depth that were set up to study their effects on the experimental performance. The experiment was parameterized by implementing 2 level of full factorial design with ANOVA analysis to measure the surface roughness of that machined surface. One-factor-at-a-time, OFAT method is applied for XRD analysis by adopting the previous parameters approach. The EDC process was aided with deionized water and pure titanium rod as the dielectric fluids and electrodes, respectively. It was determined that the high level of gap voltage provided some major constituents on the surface of NiTi alloy based on XRD analysis. As apparent, this substantiated the presence of the tool materials and their oxide layer phases. The interaction of polarity and gap voltage also indicated a significant effect towards the surface roughness.

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