Advanced Materials Research Vol. 845

Abstract: Except for the binder characteristics and molding conditions, the powder loading has a very important effect on the compact distortion. Three types of feedstocks consist of water atomised SS316L powder with 55% waste polystyrene, 35% palm stearin and 10% glycerol were prepared. The powder loading of each feedstocks are 63%, 64% and 65% respectively. Effect of glycerol at different powder loading on rheological properties in term of flowability (n), activation energy (E) and moldability (α) were investigated. It has been observed that all feedstocks possess pseudoplastic flow behavior which is one of the most crucial requirements in MIM process. The addition of glycerol decreases the flowability index while increased the activation energy.

Abstract: While the concept of remanufacturing is gaining in popularity, in practice the remanufacturing industry in Malaysia is still in its nascent stage, with approximately 32 fields in various industries claiming to be involved in the process. This is an indication for Malaysia to further develop the industry as competing developed countries already view remanufacturing as a huge business opportunity. The aim of this study is to identify and minimize the frequent failures occurring during the dismantling process. Ishikawa diagram is used to identify all possible causes of failures while the Failure Mode and Effect Analysis (FMEA) with two Risk Priority Number (RPNs), identifies the most significant failures. The case study is performed in an automotive industry as well as in a contract remanufacturing environment in Malaysia, specifically pertaining to the dismantling of cylinder heads. The work outcome of this project is expected to be the enhancement of the robustness of DfRem investigations among researchers in real life applications and to provide better solution to a wider variety of industry sectors in a developing country like Malaysia.

Abstract: There are a number of different possible End-Of-Life (EOL) treatment scenarios for products at their EOL. The decision to select the best EOL scenario for a particular product, its subassemblies and individual components, depends on multiple criteria. The performance of a particular EOL option can be better against one criterion, but might not perform satisfactorily with respect to another. To overcome the problem generated by the conflicting criteria, a multi criteria decision analysis (MCDA) technique will be used. In this project MCDA is used to develop a system which aids users to determine the best EOL scenario of products by considering the user preferences and performance of competing EOL options with respect to different affecting criteria.

Abstract: This paper presents the investigation of minimum recast layer of zirconium oxide (ZrO₂) due to micro-EDM using EDM-3 synthetic oil as dielectric fluid and tungsten as the tool electrode with control parameters of rotational speed and gap voltage. The investigation was performed using multi-process micro machine tools DT 110. The recast layer thickness was observed using scanning electron microscope and its hardness was measured using micro-Vickers hardness tester. The hardness data were analyzed and an empirical model was developed. The optimum value for minimum recast layer hardness was 873.46 Hv with rotational speed of 395 rpm and gap voltage of 110 V.

Abstract: Selective Laser Sintering (SLS) is a powder-based Additive Manufacturing process in which parts are built by sintering of selected areas of layers of Polyamide (PA12) powder using CO2 laser. The purpose of this work is to study experimentally the effect of orientation of the component, fill scan spacing and layer thickness on the surface roughness (Ra) of the customized bone implant fabricated through SLS technique. For this study computer tomography scan data was taken and converted to standard triangulation file (.stl) format using mimics software. Taguchis Design of Experiment approach was used for this study. An L27 Orthogonal Array (OA) of Taguchi design was used. Analysis of Variance (ANOVA) was then performed on S/N (Signal-to-Noise ratio) to determine the statistical significance and contribution of each factor on the surface roughness. The results indicated that orientation and layer thickness are significant parameters to cause appreciable improvement in surface finish.

Abstract: The aims of this study were to investigate the effect of gelatin coating on the mechanical property of the polypropylene (PP) composites by the addition of Multi-walled nanotube (MWNT) and gelatin coated carbon fibers. The morphology of surface of carbon fiber filament on the fracture surface was examined by field-emission scanning electronic microscopy (FE-SEM). The Iosipescu shear test was done to determine the ultimate shear strength of the PP reinforced with MWNT/gelatin composite layer coated carbon fibers. The gelatin coated carbon fibers resulted in an increase in the ultimate shear strength compared to plain carbon fibers. In addition, the ultimate shear strength was improved through the addition of MWNTs with the gelatin. Also, with gelatin acting as a binder, flying CNT particles could be minimized.

Abstract: The Cleaner Production implementation has been expanding significantly in Brazil and there is a strong tendency that companies start to care about environmental issues, such as: input reduction, production process less aggressive to the environment, among other factors inherent to manufacturing process. This paper presents a case study conducted in a company that operates in the field of automotive industry, more specifically in the manufacture of gears for transmissions and diesel engines. The main aims of this research are analyze a machining line focusing on Cleaner Production indicators and evaluate the environmental and economic benefits using the method Material Intensity Factor. The results showed that the company had both environmental benefits and financial gains due to the reduction of raw materials by means of replaced or eliminated material from the production process. The relevant aspect of this study is the possibility of financial gain associated with environmental gains and benefits by means of incremental changes in the production system.

Abstract: In recent years, the need for Silicon carbide (SiC) ceramic arises due to several industrial applications. However, the cost of machining such components is very high. Electrical discharge machining (EDM) serves as the most viable machining technique. In this study, optimum setting of sinking-EDM parameters and mathematical model of siliconized silicon carbide (SiSiC) using aluminum powder mixed dielectric fluid has been developed. Analysis of variance shows that, material removal rate (MRR) increases with high discharge current and low servo voltage, whereas tool wear ratio (TWR) and surface roughness (Ra) decreases with low current and pulse-on time. The effects of design parameters on the machining characteristics were investigated using fractional factorial (resolution V) technique. Confirmatory test was then carried out to validate the models developed.

Abstract: While the concept of remanufacturing, especially on automotive parts is gaining in popularity, in practice the remanufacturing industry in Malaysia is still in its nascent stage, with approximately 32 fields in various industries claiming to be involved in the process. The Mahalanobis-Taguchi System (MTS) is a diagnostic method employing Mahalanobis Distance (MD) for recognizing different patterns in multivariate data. The aim of this work is to apply T method-3, which is one of the sub-methods under the MTS relating to the main journal diameter of the crankshaft. The method distinguishes between two distinct ranges of acceptable remanufacturing and non-remanufacturing processes. Furthermore, the method also categorizes various patterns of crankshaft based on their MD in unit space. The case study is performed in an automotive industry in Malaysia under a contract remanufacturing environment. The outcome of this work is expected to be the enhancement of the robustness of the remanufacturing system on pattern recognition to the company under study. As a result, the company is expected to save more time and energy in coming with faster decision-making. In addition, the study would provide greater inspiration, especially among researchers in aggressively applying MTS applications to a wider variety of industry sectors especially in the remanufacturing area.

Abstract: Advanced materials like nickel and titanium have unique combinations such as low thermal conductivity, high chemical reactivity, and high hardness. Machining these materials requires suitable lubricant and proper cooling technique for increasing tool life, decreasing cutting temperature, and improving surface roughness. This paper presents a brief review done on gas-based coolant-lubricants (CLs) used in the form of either gas or cooled-pressured air and gases. Main gas-based CLs are air, N₂, and CO₂. Investigations of previous researches include hypered cooled air (at different cooling temperatures), minimum quantity lubrication (MQL), and gases which have been used on machining operation that affect tool life and surface finish. Compresed N₂ and cooled air with MQL was identified as the most suitable coolant-lubricants for machining performance. Furthermore, this type of gas-based coolant-lubricant (CLs) is considered as one of the environmentally conscious machining.