Papers by Author: Safian Sharif

Abstract: In this paper, Shielded Metal Arc Welding (SMAW) was performed on low carbon steel with three types of butt joint (i.e., square, single V, and double V) and uncapping of the weldment. The welding performance is measured based on the mechanical properties (i.e., strength and hardness). Grain size and microstructure of the weldments were also evaluated. The results show that all tested samples show similar tensile strength, which means there was no significant effect of the type of butt joint type or uncapping. The hardness of the weld metal was found to be slightly higher than that of heat affected zone and base metal, in which both showed similar hardness values. The grain size of the weld metal was also finer than that of heat affected zone and base metal. This trend in hardness and grain size on three regions of the welded sample was the same regardless of the butt joint type and whether the weldment was uncapped or not.

Abstract: Epoxy is blended with metal fillers to enhance its performance and application for tooling. Material used contains aluminium particles (Rencast CW47), blended with brass separately. Brass is added into the matrix based on 10%, 20% and 30% of the epoxy mix weight ratio. Using Taguchi method, controls factor such as pre-curing temperature (A), filler percentage (B), degassing time (C), curing time (D) and post curing temperature (E) are selected parameters in order to determine optimum conditions. Noise strategy is adopted for material cooling via ambient (N1) and oven temperatures (N2), which gave different hardness values of the epoxy composite. Optimum parameters were decided based on the prediction of S/N ratio, where A = Room temperature, B = 20%, C = 60 minutes, D = 14 hours and E = 1800C. The most significant control factor is de-gassing time for both fillers, and percentage of filler to weight ratio of epoxy mixture is optimum at 20%. It was found that brass gave higher mean hardness values, (Hv = 24.1) compared to copper (Hv = 22.7) and aluminium filled epoxy (Hv = 22.3) based on the prediction run, and suitable as additional filler to improve the surface toughness of epoxy matrix as inserts. Confirmation run was conducted according to the optimum parameters and validated the gain values for brass at 7.98. Fillers enhance the mechanical properties of epoxy matrix by increasing hardness of mould cavity and core. This work helped to design the best control factors to produce optimum hardness conditions for filled epoxy matrix.

Abstract: This paper presents the design of a survey instrument in order to determine the success factors in implementing the end-of-life vehicles (ELVs) management system in Malaysia. Upon reviewing journal articles and research papers previously conducted in automotive recycling, end-of-life vehicles, success factors and green supply chain, a set of preliminary factors was identified. These factors were categorized into seven components, namely the government commitment, stakeholders commitment, resources availability, enforcement and monitoring, education and awareness, market structure and continuous improvement. Thirty items were listed in the questionnaire, where the statements were based on the above said seven factors. Other than that, target respondents and sampling size were also discussed.

Abstract: This paper presents a research on experimental and response surface methodology (RSM) approach in evaluating the damage factor of the drilled holes in high speed drilling of glass fiber reinforced polymer (GFRP). From the experiment, the influences of drilling parameters toward damage factor are more prominent in thicker GFRP; where high speed drilling using high speed steel twist drill bit produces lower damage factor in thicker GFRP. Lastly an optimized set of drilling parameters was generated for the use of high speed steel twist drill bit in high speed drilling.

Abstract: Development of epoxy with filled particles provides an avenue for manufacturing applications in the tooling industries especially in the mould and die industries. The performance of epoxy and fillers as mould materials is greatly dependant on the production quantity and process conditions. Metal and non-metal fillers such as copper, brass, graphite and silicon carbide are blended into the epoxy matrix, altering the mechanical properties, as well as thermal conductivity of the epoxy composite. This review presents the investigation on the effect of varying composition of metal and non-metal fillers on the mechanical properties of epoxy composite. Different mixing ratios are investigated ranging from 10%, 20%, 30% and 40%, based on the weight ratio of epoxy resin, hardener and filler material. Previous studies showed that increase in amount of filler increases the hardness and compression strength of epoxy matrix. Adversely, tensile strength shows a detrimental effect with the presence of fillers, whereby increase in metal fillers reduces the tensile strength with increased composition loading from 10% to 40% of weight. Wear rate was found to reduce with the presence of aluminum, alumina and silicon carbide, hence increasing the wear resistance of the epoxy composite.

Abstract: Stainless steel, titanium alloys and cobalt chromium molybdenum alloys are classified under the metallic biomaterials whereby various surgical implants, prosthesis and medical devices are manufactured to replace missing body parts which may be lost through accident, trauma, disease, or congenital conditions. Among these materials, cobalt chromium molybdenum alloys are the common cobalt base alloy used for orthopedic implants due their excellence properties which include high corrosion resistance, high strength, high hardness, high creep resistance, biocompatibility and greater wear resistance. This paper summarises the various aspects and characteristic of metallic biomaterials such as stainless steel, titanium and cobalt chromium alloys for medical applications especially for orthopedic implant. These include material properties, biocompatibility, advantages and limitations for medical implants applications.

Abstract: In this study, waste polyethylene terephthalate (PET) polymer binder systems were used to prepare copper-graphite metal injection molding (MIM) feedstock. A mixer and screw extrusion were used to achieve optimized feedstock, and the rheological properties of the resulting fluids were evaluated using a capillary rheometry to simulate the injection molding process. The solid loadings in the copper-graphite mixes were investigated in the ranges of 51-53% using PET binder system. The effects of shear rate (γ), solid volume fraction (φ) and temperature (T) on the rheological behavior of the copper/graphite MIM feedstocks are discussed.High viscosity trend was notably recorded as shear rate increased relatively. The results indicated that this feedstock system shows dilatant characteristic and lots of further work shall be conducted in attempt to establish this as an ideal binder system.

Abstract: Selection of the most suitable tool path strategy is very essential during machining especially in computer aided design and manufacture (CAD/CAM) as well as computer numerical control (CNC) machining. Existence of various tool path strategies to be applied on advanced composite materials such as aluminium epoxy required extensive researches in determining the best combination of tool path and cutting parameters for better machinability performance. Pocket milling of aluminium epoxy specimen via CAD/CAM was conducted in this study to investigate the effect of three types of tool path strategies namely Inward Helical, Outward Helical and Back and Forth. Uncoated high speed steel (HSS-Co8) ball end mill was used throughout the experiments. The machining responses that were evaluated include machining time, tool wear rate, tool life and surface finish of the machined pockets. In general, the effect of tool path strategy was highly significant on the machining responses and results showed that Back and Forth strategy offered the best machinability results when compared to the other strategies.

Abstract: In recent years, evaluating sustainability performance of designed products has been demanded by legislations before manufacturing the products. These legislations are aimed to force manufacturers to implement sustainable end-of-life strategies in the product development phase. Although a number of studies have been conducted on integrating sustainability elements during product design and development, a tool to assist product designers in making final decision of the designed products with the most sustainability content among the alternative configuration designs has not been comprehensively investigated. In this paper, a decision tool is proposed in order to fulfill those needs. The sustainability performance is measured using Analytic Hierarchy Process (AHP) by providing a weightage of sustainability metrics throughout the total products life-cycle. An example of an armed chair is used to demonstrate this tool. This decision tool provides a new and comprehensive basis for developing sustainable products in the future.

Abstract: The surface quality generated when high speed dry end milling (HSDEM) Ti-6Al-4V-ELI titanium alloy with coated and uncoated carbide tools were investigated. Evaluation was conducted using TiAlN+TiN coated and uncoated cemented carbide tools under different high cutting speeds and feed rates conditions. Surface roughness and cutting forces were measured when using new tools. The milled surface quality and corresponding alteration were characterized through electron microscopy. Within the investigated conditions high quality surface finish was obtained on the machined surface. Increasing cutting speed from 200 to 300 m/min during the process improved the surface finished particularly under lower feed rates. In term of generated surface quality, uncoated H25 grade carbide tools out performed coated F40M grade specifically at the higher cutting conditions. The main damages observed after HSDEM on the surface for all machining conditions contain redeposited materials, feed marks, and tool edge marks. Under both tested feed rates the resultant cutting force decreased by increasing the cutting speeds and uncoated carbide tools provide the lower cutting forces compared to coated types.