S. J. Ebeid

Electrochemical machining under orbital motion conditions

Abstract The range of practical applications of electrochemical machining (ECM) is limited by relatively low machining accuracy, specially in cases of complicated shapes. One of the major problems is the generation of spikes which delay the accuracy of the process. The problem is strongly exaggerated if the tool includes multi-electrolyte holes. Moreover, additional machining processes will be needed to remove the resultant spikes. In the present work, tool orbital motion has been proposed as a new technique to enhance the ECM accuracy and to eliminate the presence of the spikes. A special test rig has been constructed for the orbital motion process. A theoretical model has been derived to predict the shape of the frontal zone, the effective machining time and the effective feed rate. The obtained results are an endeavor to provide the ECM tool designer with useful information to enhance the process accuracy. Furthermore, the results facilitate the utilization of the ECM process in die sinking and mold industry. The effect of the applied voltage, feed rate, and tool eccentricity on the spike formation are also presented.

Surface improvement through hybridization of electrochemical turning and roller burnishing based on the Taguchi technique

Abstract The present work investigates the feasibility of improving surface quality via a novel combined process of electrochemical turning (ECT) with roller burnishing (RB) using the Taguchi fractional factorial experimental design technique. To provide burnishing immediately after the ECT process, non-conductive ZrO2 rollers are attached to the tool electrode during the experiments. The Taguchi technique is employed to identify the effect of ECT working parameters such as applied voltage, electrolyte pressure, workpiece rotational speed, minimum gap, and burnishing force on the output parameters, namely, material removal rate, surface roughness, and the improvement ratio in surface roughness. From the analysis of variance (ANOVA) and signal-to-noise (S/N) ratio response graph, the significant parameters and the optimal combination level of machining parameters are obtained. Experimental results indicate that the combined process effectively improves the surface roughness and eliminates the pitting caused by ECT. Therefore, the combination of ECT and RB is a feasible process by which to obtain a refined finished surface and achieve further surface modifications.

Comparison of picture frame and Bias-Extension tests for the characterization of shear behaviour in natural fibre woven fabrics

The investigation of the shear behaviour of technical natural fibres is vital for the insurance of aesthetics and performance of light weight, high strength, and eco-friendly composites. In this study, Egyptian jute fibre plain weave fabrics of various areal densities were investigated to describe their shear behaviour in terms of shear forces, shear angles and shear lock angles, using the Bias-Extension and the Picture Frame test methods. Results show that both methods are valid for natural fibres and produce comparable results. Whereas the Bias-Extension test presents a fast and simple test procedure, the analysis of the results is more complex due to the interaction of non-shear components. On the other hand, the Picture Frame test proves to be time consuming and in need of a more complex test rig, but results in pure shear deformations throughout the sample.

Electrochemical Wire Cutting

The process of electrochemical wire cutting can be a cost-effective industrial potential in dealing with difficult-to-cut materials. This article presents the outcome of an experimental investigation into the parameter influence on EC wire cutting in an endeavour to combine minimum energy consumption with dimensional accuracy of cut. The process will then resolve into either “Slitting” or “Component Profiling”. A simple model for the action of cutting was adopted to estimate the width of cut, the values of electrolysing current and material removal rate for various parameters. Both analytical and experimental results proved the beneficial influence of increased feed rates regarding the desirable reduced width. of cut. Optimum feed rates for circular and rectangular shape wires with different sizes were defined.

Improvement of Roundness of Cylindrical Parts Using Hybrid Electrochemical Smoothing and Roller Burnishing Process

A novel finishing process, which integrates the merits of electrochemical smoothing (ECS) and roller burnishing (RB) is proposed in this research for improving the roundness error of cylindrical parts. This process can be used after various turning operations. Through simple equipment attachments, electrochemical smoothing-roller burnishing (ECS-RB) can follow the machining process on the same turning machine. To explore the optimum combinations of the ECS-RB process parameters in an efficient and quantitative manner, the experiments were designed on the basis of the response surface methodology (RSM) technique. The effect of ECS-RB parameters namely, burnishing force, applied voltage, interelectrode gap and workpiece rotational speed on the roundness error was studied. Experimental results indicate that the combined process effectively improves the roundness error. Therefore, the combination of ECS and RB is a feasible process by which it is possible to minimize geometrical errors.

Mathematical Modelling for Wire Electrical Discharge Machining of Aluminum-Silicon Carbide Composites

The increased role of advanced materials in engineering design optimization has enhanced the development of new material types. Metal matrix composites now allow the designer to select needed material properties. A key in the use of these materials is the cost effective manufacturing and dimensional control of the designed parts. Composites are a new class of engineering materials which have a high potential for many industrial applications. The traditional methods of machining these materials are very slow and expensive, and can also cause strength degradation due to the formation of subsurface cracks or other defects. The WEDM process is one of the best alternatives, for machining an ever-increasing number of high-strength, non-corrosive and wear resistant materials such as Aluminum Silicon Carbide (AlSiC).

An Operating and Diagnostic Knowledge-Based System for Wire EDM

The selection of machining parameters and machine settings for wire electrical discharge machining (WEDM) depends mainly on both technologies and experience provided by machine tool manufacturers. The present work designs a knowledge-based system (KBS) to select the optimal process parameters settings and diagnose the machining conditions for WEDM. Moreover, the present results supply users of WEDM with beneficial data avoiding further experimentation. Various materials are tested and sample results are presented for improving the WEDM performance.

Tool Design and Progressive Shape Formations During Electrochemical Broaching

The subject matter of this investigation involves the definition of progressive shape formations for a certain arbitrary tool design in the course of electrochemical broaching. The objective is to enable the designer allocate the appropriate parameters related to a broaching tool design as well as machining conditions, for attaining a reguired component configuration. The scope comprises the study of the progressive processed shapes for a sguare or triangular shape broaching tools. Comparison between experimental and analytical results proved the validity of the use of the side gap equation for predicting the processed profiles and evaluating the power consumption. The results show that the rounding-off angle is governed mainly by the tool end geometry being insensitive to its overall geometry. Improved conformity was found to be a result of the increase in both tool feed rate and approach and pyramidical angles. The results also indicate that for triangular tools, both concavity and rounding-off characterize the workpiece profile.