Advanced Materials Research Vol. 845

Abstract: Wire-EDMing process has been more accepted for cutting and slicing silicon wafer as it can provide a cut with less crack and chipping due to low effect of mechanical stresses. In order to provide a deep analysis of the process, the wire-EDMing performances and cut surface characteristics of p-type (100) monocrystalline silicon wafer have been experimentally investigated in this study. The results have shown that wide kerf width, high material removal rate, large electrode wear and rough cut surface can be obtained under the condition of high open voltage and rough cutting mode. Some micrographs of cut surface morphology have been also reported and discussed, where many craters and small holes can be apparently seen on the machined surface.

Abstract: The great negative impact of oil spill to the environment and living things over the years have necessitated the need for much study on improving and developing of sustainable natural absorbents in recent time. This paper reviews the adverse effect of oil spill, controls measures and proposes future recommendations for the usage of some agricultural products with promising oil absorbent potency.

Abstract: The demand for mechanical fastening in composite materials is increasing due to their potential in large assemblies, aerospace and automotive industries. In practice, small components are integrated into large assemblies drilling holes in composite materials. Drilling defect free holes in composite presents many challenges during part assembly and services. This study presents the effects of cutting parameters used for drilling holes in glass fiber reinforced polymeric (GFRP) composites and hybrid fiber reinforced polymeric (HFRP) composites. Both the composites plates of 3 mm thickness were fabricated using a hand lay-up technique for the purpose of evaluating the effects of parameters on the quality of drilled holes. The holes were drilled using a 5 mm solid carbide twist drill at different spindle speed and feed rate. The quality of holes was assessed with respect to damage factor (F_d) and surface roughness (Ra) of the drilled holes. Results showed that the HFRP composite experienced lower damage factor (F_d) as compared to GFRP composite at lower feed rate or spindle speed. Scanning electron microscopic (SEM) examination revealed that the occurrence of delamination, fiber pull-out and matrix cracking was accelerated in the drilled holes at high spindle speed and feed rate.

Abstract: Surface integrity of machined component is of major importance for the reliability and safety requirements during in service especially for the aerospace applications. This paper presents an investigation on the effect of drill geometry on the surface integrity of drilled hole of Ti-6AL-4V during drilling operation. Drilling experiments were conducted under the MQL using a special vegetable oil known as Jatropha oil. Experimental results revealed that drill point angle and coolant-lubricant conditions significantly influence the surface integrity which include surface roughness, micorhardness and microstructure defects. The surface roughness decreased with greater drill point angle. The subsurface deformation layer thickness was approximately 9 - 15 μm from the top of the machined surface. Microhardness profiles of the last hole indicated that the subsurface deformation extend up to a 150 to 200 μm until it reaches to the average hardness.

Abstract: Aerodynamicists have long acknowledged the blended wing body (BWB) aircraft design could produce great aerodynamic advantages due to the integration of the delta wing structure with the thick center body. Therefore the wind tunnel test campaign is crucial to gain information of the flow field that governs the delta-shaped wing which has frequently baffled the aerodynamicists. In such, the wind tunnel test required acceptable quality of delta-shaped wing model for results validity. Consequently, the manufacturing process as well as the selection of the appropriate machinery tools, must be wisely designed and performed. The modular 3D concept in associating with CAD/CAM technology was utilised in the process. Finally, the actual flow cycle of manufactures blended BWB aircraft model was sucessfully established. The objective of this paper is to highlight those complexity manufacturing process and techniques involved in order to produce a good blended delta-shaped wind tunnel model.

Abstract: In this paper, a framework for remote monitoring and controlling of manufacturing system at lower level of automation in manufacturing is proposed. This framework has capability to develop the higher level of automation in manufacturing. In order to proof that the proposed framework can be implemented, a demo system based on the framework is built.Computer-Integrated Manufacturing (CIM) system as a manufacturing system is controlled and monitored remotely within demo system was utilised. In general, the system consists of two Graphical User Interface (GUI) program; one as a client and the other one as server program connected using TCP/IP protocol. The system proposed include the CIM system which connected to the server computer and able to controlled and monitored via the client GUI program. In addition for demonstration purposes, several sub-systems of the CIM system which includes the conveyor, stoppers, sensors and the pick and place robot were used to control and monitor the system development. The programming language used in this system is Visual C++ with Microsoft Foundation Class (MFC) application. The overall developed system has successfully demonstrates the ability of remotely control the system.

Abstract: Micro-machining is a fundamental process for manufacturing parts and products with dimensions of between 1 to 999 μm. Micro-Electro Discharge Machining (micro-EDM) has been used for producing of parts, molds, dies, cavities and complex three dimensional shape regardless of hardness and strength. Micro-electrodes are required for these purposes and usually micro EDM machines are used for fabricating them. Moving block electro discharge grinding (Moving BEDG) is one of the processes that can be used to fabricate micro-electrode. In this study a conventional EDM machine is used for fabricating the micro-electrode. Based on the characteristics of this machine some changes need to be applied to the moving BEDG for micro-electrode fabrication. Modification made to the moving BEDG include changing the direction of movement and control gap, use of roughing, semi finishing and finishing electrodes in one electrode. Consequently set up and machining time was decreased due to the use of roughing, semi finishing and finishing parameters. Finally, high aspect ratio micro electrode with diameter of 160.8μm was fabricated. As this process is simple and does not require high investment for special equipment; it can be used even by an ordinary workshop equipped with a conventional EDM machine.

Abstract: Fabrication of nanofibers using electrospinning has recently attracted much attention for various applications due to its simplicity. Electrospinning has the ability to produce nanofibers within 100-500 nm. Some applications require certain fiber diameter. As a relatively new process, there are many electrospinning parameters that are believed to influence the nanofibers diameter. The purpose of this review is to identify and discuss the effect of some of those parameters, i.e. concentration, spinning distance, and applied voltage, and volume flow rate, to the nanofiber diameter during electrospinning process. It was concluded that fiber volume flow rate is proportional to fiber diameter while there is no agreement in reports on other parameters.