Azli Yahya

Comparison Studies of Electrical Discharge Machining (EDM) Process Model for Low Gap Current

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.

Predicting Material Removal Rate of Electrical Discharge Machining (EDM) using Artificial Neural Network for High I gap current

This article presents a prediction of Material Removal Rate (MRR) in Electrical Discharge Machining (EDM) using Artificial Neural Network (ANN). Experimental data were gathered from Die sinking EDM process for copper-electrode and steel-workpiece. It is aimed to develop a behavioral model using input-output pattern of raw data from EDM process experiment. The behavioral model is used to predict MRR and than the predicted MRR is compared to actual MRR value. The results show good agreement of predicting MRR between them.

PID controller tuning by particle swarm optimization on electrical discharge machining servo control system

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.

Fabrication and characterization of polycaprolactone (PCL)/gelatin electrospun fibers

Over the past few decades, there has been considerable interest in developing electrospun fibers by using electrospinning technique for various applications. Polymer blending is one of the most effective methods in providing desired properties. In this study, synthetic polymer polycaprolactone (PCL) was blended together with natural polymer gelatin where both of them have different properties. It is done by using electrospinning technique. 10 %w/v and 14 %w/v PCL/gelatin electrospun fibers were successfully electrospun with different weight ratio. Processing parameters were set constant in this study and only solution parameters were altered. The optimized electrospun fiber formed was 14 %w/v PCL/gelatin 70:30 with average fiber diameter of 246.30 nm. No beaded fiber was formed in this scanning electron microscope (SEM) image. The result obtained also showed that by increasing the overall polymeric concentration of PCL/gelatin, average fiber diameter decreases. Fiber diameter was also found decreasing with the increase of the concentration of gelatin in the same concentratoin of PCL/gelatin blended electrospun fiber. Blending of PCL and gelatin in different weight ratio had provided different properties of electrospun fibers. It is believed that blended electrospun fibers can be used for biomedical applications.

Implementation of Ant System for DNA Sequence Optimization

In DNA based computation, the design of good DNA sequences has turned out to be a fundamental problem and one of the most practical and important research topics. Although the design of DNA sequences is dependent on the protocol of biological experiments, it is highly required to establish a method for the systematic design of DNA sequences, which could be applied to various design constraints. Much works have focused on designing the DNA sequences to obtain a set of good DNA sequences. In this paper, Ant System (AS) is proposed to solve the DNA sequence optimization problem. AS, which is the first approach proposed in Ant Colony Optimization (ACO), uses some ants to search the solutions based on the pheromone information. A model is adapted, which consists of four nodes representing four DNA bases. The results of the proposed approach are compared with other methods, such as evolutionary algorithm.

A flyback SMPS LED driver for lighting application

This paper proposes an isolated flyback switch mode power supply (SMPS) light-emitting diode (LED) driver for lighting application. The LED driver features a single-stage AC/DC converter with minimal number of components which help to cut its cost. The LED driver is using a single switching transistor, without supplementary inductors, correctional circuitry, or clamping action, thus ensuring a low cost design. The SPICE modelled LED driver uses auxiliary voltage output to maintain the equilibrium of the system based on the feedback from the output. Simulation models report up to 95.44% efficiency.

Power Generator of Electrical Discharge Machining (EDM) System

Electrical Discharge Machining (EDM) is a non-conventional manufacturing process of removing materials. The uniqueness of EDM process is the removal of the unwanted materials without direct contact between the electrode and workpiece. EDM power generator provides power source of EDM system. It supplies voltage and current to produce spark erosion. Power supply and pulse generator are two important parts in EDM power generator. By choosing the proper power supply and pulse generator to the application, a great result for Material Removal Rate (MRR) can be achieved. Efficiency of EDM power generator depends on the configurations of power supply used. This study reviews and summarizes some previous development of EDM power generator and their effectiveness.

Gap response of linear and non-linear discharge model in Electrical Discharge Machining System

In recent years, simulation-based research is highly appreciated. So many researchers use this way to investigate and solve some problems. Empirical model or behavioral model is used to bring the problems into computer or other computing devices. Selection and determination of the model is very important on the outcome of research. In Electrical Discharge Machining system, servo control system uses voltage drop between electrode and workpiece as a feedback signal. Discharge phenomenon convert gap or distance between electrode and workpiece to voltage. In this paper, two discharge models are simulated and compared. Simulation results show that there are behavior’s differences between these models.

Model of Pulse Power Generator in Electrical Discharge Machining (EDM) System

Electrical discharge machining (EDM) is a non-traditional manufacturing process of removing material. EDM system consists of a shaped tool and the work piece, which are connected to a power supply and placed in a dielectric fluid. EDM pulse power generator applies voltage pulses between the electrode and workpiece to generate sparks through the gap. The essential requirement for EDM system is to obtain the output waveform similar to the ideal EDM waveform. The design is based on transistor type pulse power generator circuit. This paper discuss in modeling of current and voltage gap waveform for EDM system.

Control strategy for Electrical Discharge Machining (EDM) pulse power generator

Electrical Discharge Machining (EDM) is a advanced machine that can control electrical spark to erode metal on the workpiece. In manufacturing, EDM is used on hard material parts that are extremely difficult to machine by conventional machining processes. EDM system consists of a shaped tool and the work piece, which are connected to a power supply and placed in a dielectric fluid. EDM pulse power generator applies voltage and current pulses between the electrode and workpiece to generate sparks through the gap. To obtain the optimum metarial removal rate (MRR), a good alternative is to improve the gap voltage and gap current. A proposed solution to these issue is combining ultracapacitor bank to the main power supply circuit for EDM machines. The control feedback of this research is designed to make sure that the current on DC bus is maintained at current setting during the machining processes.