Advanced Materials Research Vols. 264-265

Abstract: This paper presents the comparative study between the strain signal and its edited signal. In this study, a fatigue strain loading was measured on an automobile coil spring, and the purpose to analyse this component is because it been identified as one of the critical component in an automobile. The strain signal editing process was performed by removing low amplitude cycles contained in the original signal using the short-time Fourier transform (STFT) method. This low amplitude cycles were eliminated based on the cut-off level of the signal energy distribution in the time representation. The original and edited strain signals were then analysed for predicting the fatigue damage of the coil spring. A comparison study of the fatigue damage and the most damaged zone obtained from the strain signal and the edited strain signal was also carried out. It was found that, the prediction of the fatigue damage and the most damages zone for both signals was same. Hence, the shortened signal can be used in the laboratory fatigue testing for the purposes of accelerated fatigue testing.

Abstract: Defining and generating a working drawing of a conical spur gear to replace an original piece requires geometrical and dimensional constraints, especially when the cutting module is determined by reverse engineering. We propose an approach using Computer aided design (CAD) to establish the drawing definitions and to verify the assembly of the conical spur gear. We have developed the model drawing according to the standard International Standard Organisation (ISO), in which we introduce a new non-existent coast into the current dimensioning and check the assembly using the Tredgold method, which transforms a conical spur gear into a model cylindrical spur gear, to which the equations for parallel cylindrical gearing can be applied. This method determines a good estimate if the couple of gear verifies the specified geometrical conditions of assemblies. We present the developed algorithms, as well as the results of applications of various programs.

Abstract: The paper presents an implementation of parallel computing technique in Finite Element Method to simulate the nosing of circular tubes. An earlier developed code FEMLD has been updated to simulate the nosing process of circular tubes. The code was originally developed to simulate the axial and lateral compression of metallic tubes of various shapes [8] on platform of supercomputer PARAM 10000. A parametric study has been carried out on tube specimens and the obtained results are presented. On the basis of the obtained results, the mechanics of the nosing process is presented and discussed. Various components of computational time has been obtained and presented to evaluate the performance of developed code for parallel computing. The time variation and speedup with number of processors is also discussed.

Abstract: High precision micro screws have been widely required for the fastening parts of electronic storage devices. Teeth’s forming of the micro screw is generally utilized by a cold thread rolling process with a flat die. This process for micro sized parts has some difficulties such as the design of die shape, alignment between dies, and process managements. In this paper, it is focused on the effect of the alignment between dies and material, and process parameters in simulation. The investigated parameters are the friction coefficient and the relative position between stationary and moving dies using a numerical simulation. The simulations provide that the shear friction factor of 0.9 is proper for preventing slip between dies and raw material and the relative position of two dies has to be set to the half length of the pitch for maintaining the continuous thread profiles. The deformed shapes of the pitch part and the top part of threads can be demonstrated the feature of experimental result. The folding phenomenon appeared at the top part of threads, which seemed to be induced by a lack of the metal flow under micro sized deformation.

Abstract: In this paper, a design system combining clinical experience and engineering knowledge was developed for the manufacture of custom-made femoral stem. The medical image of the hip obtained according to the patient X-rays. The geometric parameters for femoral stem were established based on the canal flare index. The necessary constrains based on surgical experience were integrated into the CAD system. The rapid prototyped model was built as the reference for review. Through the application of CAM software, the interference-free toolpath and the cutter location for multi-axis NC machining are generated. In order to establish the interface between the design and the manufacture of femoral stem, the postprocessor for multi-axis machine tool is developed. The cutting simulations with solid model are performed to verify the generated toolpath. It is also verified through the trial-cut with model material on a five-axis machine tool.

Abstract: Rapid prototyping (RP) can efficiently fabricate high level models with complex shapes. Hence the RP has been widely applied in various industrial fields. However, as the technology is inherently performed by layered manufacturing process, the surface quality of the RP part is not satisfactory to use general industrial purpose. This is the reason that surface roughness problem has been key issue in RP. In this paper, relation between surface roughness and overlap interval is investigated based on a surface roughness formulation in fused deposition modeling (FDM). Additionally, effects of surface angle and filament shape are analyzed and discussed to predict surface roughness distribution by the overlap interval variation.

Abstract: Scalable Video Coding (SVC) is the extension of the H.264/AVC standard. The SVC has good capability in video transmission systems because of its scalability which can adapt in different network conditions, especially in low bit rate transmission. The objective of this paper is to develop the low bit rate video coding for assisting the remote operation of Command and Control (CNC) milling process through virtual simulation and remote desktop interface. The algorithm for low bit rate video coding will be in the downsampling of high resolution layer before the encoding process and upsampling the high layer data in the decoder. Based on simulation results, the proposed scheme shows good performance in maintaining the video quality at 128 kbps while providing high time savings for the encoding process.

Abstract: The purpose of the present experimental investigations is to study the effect of moulding sand properties on reducing the shell wall thickness of mould cavity for cost effective, hybrid rapid casting solution of zinc alloy. Starting from the identification of component/benchmark, technological prototypes were produced, with three different moulding sands (dry, green and molasses), at different shell wall thickness of mould cavity using hybrid rapid prototyping technique (combination of three dimensional printing and conventional sand casting). Measurements on the coordinate measuring machine helped in calculating the dimensional tolerances of the castings produced. Some important mechanical properties were also compared to verify the suitability of the castings. The study suggested that for the shell thickness, having value less than the recommended one is more suitable from dimensional accuracy and economic point of view, for all three moulding sands. Further best shell wall thickness of the mould cavity for different moulding sands, for the selected component/benchmark has been highlighted for rapid casting solution of zinc alloy.

Abstract: Advanced development of computer network through Internet brings the technology to Manufacturing. Increasing the demand for effectively use of the production facility requires the tools for sharing the manufacturing facility by remote operation of the machining process. This paper introduces the methodology of machining technology for direct remote operation of networked milling machine. The tools including virtual simulation using CAD model, remote desktop protocol and Setup Free Attachment for remote operation of milling process are proposed. Accessing and monitoring of machining operation is performed by remote desktop interface and 3D virtual simulations. Capability of remote operation is supported by an auto setup attachment with a reconfigurable pin type setup free technology installed on the table of CNC milling machine to perform unattended machining process. The system is designed using a computer server and connected to a PC based controlled CNC machine for real time monitoring. A client will access the server through internet communication and virtually simulate the machine activity. The result has been presented that combination between real time virtual simulation and remote desktop tool is enabling to operate all machine tool functions and as well as workpiece setup.

Abstract: Composite materials have become a popular material substitution for automotive, sports, medical, aerospace and other engineering fields due to their light-weight, high strength and/or stiffness of fibres. In this paper, a conceptual design approach has been presented to develop aluminium metal matrix composite (AMC) automotive brake rotor system. A systematic and stepby- step approach of full design is shown for better understanding of the design concept of automotive brake rotor. The methodology of conceptual stage, computer aided design (CAD) and evaluation systems are discussed for illustrating and selecting the best concept. A total of six (6) concepts for both surface rejuvenates feature and ventilated cooling fins are explained. It was found that the Concept 6 for surface rejuvenates feature and Concept 1 for ventilated cooling fins are the best combination for aluminium metal matrix composite brake rotor application.