Showing papers by "Azli Yahya published in 2012"
TL;DR: In this article, the authors compared a Dimensional Analysis (DA) model, an Artificial Neural Network (ANN) model and an experimental result for a low gap current of an Electrical Discharge Machining (EDM) process.
Abstract: This paper aims to compare the material removal rate, ν between a Dimensional Analysis (DA) model, an Artificial Neural Network (ANN) model and an experimental result for a low gap current of an Electrical Discharge Machining (EDM) process. The data analysis is based on a copper electrode and steel workpiece materials. The DA and ANN model that have been developed and reported earlier by authors are used to compare the material removal of EDM process. The result indicated that the ANN model provides better accuracy towards the experimental results.
612 citations
05 Apr 2012
TL;DR: In this paper, a new design of Pulse Power Generator was proposed by considering the optimum material removal rate, the relative wear ratio, the surface crack density and the surface finish quality of the workpiece produced.
Abstract: Electrical Discharge Machining is a non-contact machining process for shaping and forming deep and complex-shaped holes for all kinds of electro-conductive materials regardless of their hardness. Recently, a demand in micro machining has extended into biomedical application for lubrication of artificial human joint. A micro pits formation is therefore proposed for lubrication purpose, which eventually prolong the lifespan of the hip implant. In this case, particular size of crater in micro will be developed in various positions and depth on the artificial joint surface to ease friction between metal joint. Therefore, this paper proposes a new design of Pulse Power Generator by considering the optimum material removal rate, the relative wear ratio, the surface crack density and the surface finish quality of the workpiece produced.
10 citations
12 Jun 2012
TL;DR: The main goal of this work is to get PID parameters through Particle Swarm Optimization (PSO) algorithm to ensure a stable, robust and controlled system.
Abstract: Electrical Discharge Machining (EDM) is included in a stochastic process. So maintaining gap between electrode and workpiece is not easy. In order to control the gap, a proportional integral derivative (PID) controller is designed for EDM servo actuator system. The main goal of this work is to get PID parameters through Particle Swarm Optimization (PSO) algorithm to ensure a stable, robust and controlled system. The controller and the model for EDM die sinking are verified by simulation of the control system using MATLAB and simulink program. Simulation results verify the effectiveness of the PID controller in which its parameter determined by PSO to control the electrode position towards workpiece.
9 citations
01 Oct 2012
TL;DR: In this article, a variable-frequency, soft-switching, snubbed, DC/DC flyback converter that utilizes valley switching for improving efficiency is presented. And the flyback controller is modelled using SPICE, and uses pulse skipping to maintain the equilibrium of the system based on the feedback from the output.
Abstract: The flyback switching mode power supply (SMPS) circuit is undoubtedly the most popular topology currently in low power applications, due to its low cost and simple structure. In the past, there have been many proposed optimizations to flyback designs utilising various techniques such as zero voltage switching (ZVS), active clamping, synchronous rectification, and more. However, most of these designs complicate the original snubbed structure of the flyback topology, and increases its cost. This paper presents the evaluation of a variable-frequency, soft-switching, snubbed, DC/DC flyback converter that utilizes valley switching for improving efficiency. The flyback controller is modelled using SPICE, and uses pulse skipping to maintain the equilibrium of the system based on the feedback from the output. Simulation models report up to 92.2% efficiency, which is almost comparable to ZVS and active clamping topologies. The main advantage of this design is the use of only a single switching transistor, with no additional inductors, correctional circuitry, or clamping action, thus guaranteeing a low cost design.
9 citations
05 Apr 2012
Abstract: Hip implant is an orthopedic procedure which the hip joint is replaced by prosthetic or artificial implant in order to replace arthritic or dysfunctional joint surface. The process is also known as hip arthroplasty. However, the metal-on-metal hips articulation suffers from friction due to the moving metal surface thus, shortening the surviving of the joint. A micro pits formation is therefore used for lubrication purpose, which eventually prolong the lifespan of the hips. This paper will focus on the methods for machining the micro pits in terms of work piece placement, coordination and orientation related to the electrode of electrical discharge machining system for lubrication purpose. A new structure of work piece positioning system would be designed accordingly in order to optimize the machining performance and improve lubrication activities in the hip implant device.
5 citations
12 Jun 2012
TL;DR: In this paper, a comparison study between two erosion rate models, Dimensional Analysis (DA) and Artificial Neural Network (ANN), was performed on a copper electrode and steel workpiece materials.
Abstract: This paper reports a comparison studies between two erosion rate model and experimental results of an Electrical Discharge Machining (EDM) process for high gap current. Two erosion rate models are Dimensional Analysis (DA) model and Artificial Neural Network (ANN) model that have been summarized from the previous author's publication. The data analysis is based on a copper electrode and steel workpiece materials. The result indicated that the ANN model provides better accuracy than the DA model when compared to the experimental results.
1 citations