Advanced Materials Research Vol. 845

Abstract: Electrical discharge machining (EDM) is a non-conventional machining process where materials are removed by the thermal energy exerted from series of electrical sparks. This process is applied for machining of non-conductive alumina (Al₂O₃). The workpiece is covered with the adhesive copper foil to initiate the initial spark between the workpiece and the tool electrode. A pyrolytic carbon (PyC) layer is generated on workpiece surface by dissociating kerosene dielectric after the machining of initial copper assisting electrode (AE) layer. In this study, experiments were performed by varying the peak current and keeping other parameters constant in order to investigate the effect of peak current on material removal rate (MRR) in EDM of Al₂O₃. The results showed that the lowest and the highest values of peak current were 1.1 A and 1.3 A, respectively. Material cannot be removed due to insufficient PyC layer generation for any values of peak current less than 1.1 A or more than 1.3 A. From the results, it is also observed that the MRR is increased when higher peak current values are used. MRR was found to be 0.052 mm³/min at peak current 1.1 A and it was found to be 0.132 mm³/min at peak current 1.3 A.

Abstract: Titanium dioxide (TiO2) has widely been applied in various fields of industry and technology. To improve the corrosion resistance of TiO2, many manufacturing processes have been researched. MAO is a new method of the TiO2 manufacturing process, of which titanium dioxide is coated on titanium substrate. According to electrochemistry researches, there is a more superior level for Pulse-MAO than traditional MAO. Parameters of on-time were significant in the Pulse-MAO process. The results show that on-time affects reactant shape, morphologies, thickness of films, and corrosion resistance. When on-time increased, the size of reactants was bigger and the shape of reactants was changed from sphere to lump. Meanwhile, the corrosion resistance and thickness of the film increased.

Abstract: Robot programming demands skilled robot programmers. Conventional methods of robot programming include teaching robot using the teach pendant and the high level programming language. Teaching robot kinematics and solving kinematic problems are complex and they involve robot programming. With the advancement of computer and robotic technologies, this can be solved via computer simulation. In this paper, an approach for programming the robots manipulator via an offline virtual kinematic learning tool is proposed. A virtual system is developed which has a user interface for users to improve the knowledge of the robot manipulators kinematic. Basic kinematics note, exercise and forward kinematic calculation based on Danavit Hertenberg method was included in the system. A template will be provided to the user as a guide to develop the controller to control the simulation of the virtual robot. The input and output method will be used to transfer data from the controller to the offline kinematic learning tool. After receiving the input, the data is stored in a text file. This data will provide the value of each angle of the virtual robots to allow the system to generate the final position of the virtual robot and the virtual robot manipulator will be displayed and animated accordingly. Besides that, the offline robot programming will be generated by the system according the simulation planned by the user. This offline virtual kinematic simulation will help to provide a better understanding of the robot manipulators kinematic.

Abstract: Surface texture assessment is very useful in predicting the functional behaviour of engineering components. Surface texture is composed of three elements-roughness, waviness and form Error. The proposed method analyzes surface texture in two ways-Subjective analysis and Objective analysis. Subjective analysis makes use of histogram and texture spectrum whereas objective analysis uses Grey Level Co-occurrence Matrix (GLCM) based standard texture descriptors. Different milled surfaces having different textures are prepared by varying the machining parameters. The proposed method is non-contact in nature and high measuring speeds are possible. The method provides a complete texture description for a given surface.

Abstract: This paper presents a mechatronic development of a new mobile robot platform for autonomous on-the-road navigation. It uses sensor fusion involving the camera, laser range finder (LRF) and odometry to guide and find the free collision path during navigation. The embedded controller system has been deliberately developed to integrate the mechanical parts with the electronics and software algorithms. Microsoft Visual C# and MATLAB are linked together to perform the road recognition calculation via the proposed algorithms. The main processing program in C# is later extended to MATLAB environment for image, signal processing and calculation based on data from the LRF and camera. The linking between C# and MATLAB is done using COM automation server and the data in the client C# program passes it to MATLAB and vice versa.

Abstract: A remanufacturing is an independent institution in which a variety of activities such as disassembly, inspection, disposing, refurbishing, repairing, remanufacturing, transportation and reassembly are performed. We propose an approach that uses an open queuing network, decomposition principle and expansion methodology to analyze the remanufacturing system and use Taguchi method to find out how much the buffer sizes affect on performance. The objective function values, throughput and total cost, are calculated for each experiment. Main effects plots show how each factor affects the response characteristic.

Abstract: Vibration tendency can rise in turning process when selecting a cutting tool with larger nose radius and/or increasing the feed rate. As consequence, it may affect the process performance by reducing the tool-life and causing damage to the machined surface finish. Moreover, the generated surface roughness strongly depends on the relation between feed rate and cutting tool nose radius. The wiper cutting tool is a recent technological advancement which is claimed to allow both the feed rate and the depth of cut to be doubled while maintaining the same surface finish value in comparison with standard tools. Thus, the objective of this paper is to benchmark tool-life of standard and wiper cutting tools in dry finish turning of SAE 4140 steel. The analysis consists of successive measurements of workpiece roughness and tool corner wear after each turning pass while using combined machining parameters for a target roughness average value close to 2 μm with both inserts being used under the manufacturers recommended cutting conditions. It is noted that the two inserts presented good performance both in the workpiece finish and in tool-wear.

Abstract: Machining performance consists to associate the optimal process and cutting parameters and maximum material removal rate with the most appropriate tool while controlling the machined surface state. This work verifies the influence of standard and wiper cutting tools on generated surface roughness and residual stress in dry finish turning operation of the martensitic stainless steel AISI 420 in a comparative way. Tests are conducted for different combinations of tool nose geometry, feed rate and depth of cut being analyzed through the Design of Experiments regarding to surface roughness parameters R_a and R_t. Moreover, the formation of residual stresses in the material (using the technique of X-Ray Diffraction) was evaluated after the machining process for these two cutting geometries and thereafter the result was compared between them. An ANOVA is performed to clarify the influence of cutting parameters on generated surface roughness, which outputs inform that cutting tool geometry is the most influent on R_a and R_t. It is concluded that analyzed wiper inserts present low performance for low feed rates. Regarding the analysis of the residual stresses it can be stated that for standard and wiper tools the values collected show that for finish turning the compression stresses were found. It can be observed that the greatest amount of compressive stress has been found for the standard tool.

Abstract: In the manufacturing industry, managers and engineers are seeking to find methods in order to eliminate the common problems in manufacturing systems such as bottlenecks and waiting times. This is because that all of these kinds of problems impose extra cost to the companies. In addition, manufacturing companies are striving to sustain their competitiveness by improving productivity, efficiency and quality of manufacturing industry for instance high throughput and high resource utilization. The paper concentrates on the application of computer simulation to analysis manufacturing system in order to improve the productivity. Therefore, this study introduces a color manufacturing line as a case study and the basic application of arena 13.9 software. The goal of this paper is to improve the productivity and efficiency of the production line by using computer simulation. To achieve this goal, first the basic model of the current situation of production line was simulated. Second, three different alternatives were simulated and modified to find the best scenario based on the maximum productivity and minimum total cost.

Abstract: Effect of variation of the connection (butt joint) in low carbon steel resistance welding (shielded metal arc welding, SMAW) performance is investigated in this paper. Three types of butt joint was varied: square, single V, and double V. The results from tensile test showed that welded specimens are of similar tensile properties with base metal and one another. When hardness test was performed on weld metal, HAZ, and base metal of each specimen,.it was found that weld metal and HAZ were of higher hardness than the base metal. Specimen with square joint exhibits the highest hardness while specimens with single V and double V joints show similar hardness. Microstructure analysis revealed that weld metal of specimen with square joint is of bainite-martensite phases while weld metal of specimens with single V and double V joints are of ferrite-pearlite phases. This difference in microstructure, and hence in hardness, is related to the corresponding heat input during welding.