Advanced Manufacturing and Processing Technology

Chander Prakash, Sunpreet Singh, J. Paulo Davim, Chander Prakash, Sunpreet Singh, J. Paulo Davim

• Publisher: CRC Press
• Year: 2020
• Print ISBN: 9780367275129
• eBook ISBN: 9781000193282
• Topic: Technology & Engineering
• Subtopic: Mechanics
• Index: Technology & Engineering

This book disseminates recent research, theories, and practices relevant to the areas of surface engineering and the processing of materials for functional applications in the aerospace, automobile, and biomedical industries.

The book focuses on the hidden technologies and advanced manufacturing methods that may not be standardized by research institutions but are greatly beneficial to material and manufacturing industrial engineers in
many ways. It details projects, research activities, and innovations in a global platform to strengthen the knowledge of the concerned community. The book covers surface engineering including coating, deposition, cladding, nanotechnology, surface finishing, precision machining, processing, and emerging advanced manufacturing technologies to enhance the performance of materials in terms of corrosion, wear, and fatigue.

The book captures the emerging areas of materials science and advanced manufacturing engineering and presents recent trends in research for researchers, field engineers, and academic professionals.

1 A Critical Review on the Machining of Engineering Materials by Die-​Sinking EDM

P. Sreeraj, S. Thirumalai Kumaran,
M. Uthayakumar, and S. Suresh Kumar

Kalasalingam Academy of Research and Education

Contents

1.1 Introduction

1.2 Researches on Electrical Discharge Machining Process

1.2.1 Researches on Enhancement of Tool Wear

1.2.2 Optimization of Process Parameters

1.2.3 Selection of Electrode Material

1.2.4 Multispark Erosion Studies

1.2.5 Selection of Optimized Pulse Duration

1.2.6 Vibratory Tool and Workpiece

1.2.7 Introducing Servo Control Mechanism

1.2.8 Magnetic Field–Based Electrical Discharge Machining

1.2.9 Special Tools

1.2.10 CNC-​Controlled Electrical Discharge Machining

1.2.11 Selection of Dielectric Medium

1.3 Application of Electrical Discharge Machining for Biomaterials

1.4 Conclusions

References

1.1 Introduction

In automotive and aerospace industries for producing complicated shapes of high hardness and toughness, electrical discharge machining (EDM) has been commonly used [1]. Conversion of electrical energy to thermal energy is taking place by means of discrete sparks through separating dielectric medium, which causes material removal. Plasma channel is generated between electrodes, and this high temperature around 20,000°C melts the electrodes, which cause the material removal. When the plasma channel breaks down, materials are flushed away by means of circulating die electric fluid, which actually causes material removal.

Nowadays, EDM is employed as a standard technique for machining of hardened new-​generation alloys where traditional machining techniques have proved to be inefficient. Frequent changes of electrodes are required because of rapid tool wear. Machining accuracy of process is also influenced by tool wear, and hence, cost of replacement of the tool increases. In EDM, tool and workpiece have been considered as electrodes, and erosion occurs on both the electrodes. Electrode wear can be classified into four types such as volumetric, corner, end, and side wears [2]. Among them, corner wear has significant influence on affecting the accuracy of machining.

Minimization of electrode wear is one of the research areas to be concentrated in EDM. Considerable research has been done in this area for the minimization of tool wear rate (TWR). Likewise, improvement of material removal rate (MRR), that is, maximization of machining rate and improvement of surface quality (SQ), is also a major challenge for researchers. When an electrode is connected to negative polarity, MRR found to be influenced by recast layer creation. Regarding quality of each prepared surface EDM, it consists of three layers such as recast or white overlay, heat-​affected zone, and original substrate material. For improving SQ in machining through research, these three layers are required. Quality of machined surface depends on white layer because it is the topmost layer exposed to atmosphere [3].

This chapter concentrates on standard techniques suggested and contributed by different authors for the reduction of tool erosion rate, maximization of material expulsion rate, and SQ. Furthermore, scope for future work has been proposed, and it may be helpful for those who conduct studies in the field of EDM.

1.2 Researches on Electrical Discharge Machining Process

A complete analysis of research activities conducted in the past decades in die-​sinking EDM process has been discussed in this section. There are quantitatively good advantages in EDM such as high precision production of mirror image. In spite of these advantages, EDM has many disadvantages such as formation of surface cracks, metallurgical changes in surface and subsurface regions, formation of recast layers, and formation of heat-​affected zones. Researchers have devised many methods to overcome these deficiencies of EDM. The following sections describe the methodologies and strategies adopted in EDM process for enhancing the efficiency and quality of machining.

1.2.1 Researches on Enhancement of Tool Wear

Melting of electrodes, due to powerful dislodgement of superheated electrodes at the end of each pulse, causes material removal in EDM. In this development, both tool and workpiece undergo some surface changes because of this melting phenomenon. Many researchers have studied about workpiece modification, abatement of tool wear, and maximization of MRR. Equally important issue is reduction of tool wear. Soni et al. [4] have noticed that appreciable quantity of material migrates from workpiece to tool by forming a protective layer, which causes the reduction of tool wear. Marafona et al. [5] have proved that reduction of tool wear is achieved by a protective thin film of carbon formed on the surface of the tool. Researchers have also shown that this carbon film has considerable effect on reduction of tool wear but has no role on MRR. Marafona [6] has found that because of shift of carbon from circulating dielectric medium, a black surface on tool (W/Cu) is produced while machining the workpiece BS 4695 D2, and the presence of iron, chromium, vanadium, and molybdenum in black layer is also found. These elements present in tool surface form carbon equivalent, which is the main reason for the reduction of tool wear.

Mohri et al. [7,8] proved that in the beginning of machining, electrode wear is more at the edge than flat portion, and it increases in longitudinal direction. In the edge portion, proper deposit of carbon does not take place from die electric during sparking process, and it is the main reason for more wear in the edge portion. Researchers have reported that by providing proper protective layer on tool surface and by using dry medium, the tool wear can be minimized considerably. The ultimate aim of the new researchers is to obtain zero wear electrodes.

In order to achieve improvement in mechanical properties, a recast film has been on EDMed surface of AISI H13 tool steel. Amorim et al. [9] have conducted experiments with electrolyte copper as electrode and hydrocarbon oil as die electric with suspended molybdenum (Mo). The results have indicated that a coating has been formed on the surface and it has improved hardness and other mechanical properties.

1.2.2 Optimization of Process Parameters

Input parameters influence various aspects such as material depletion rate, surface irregularities, tool erosion rate, radial over cut, cutting width, cutting agility, and crater width. By controlling and optimizing major process parameters, the quality of machining can be improved [10]. EDM of Al–10% SiCp composite has been carried out by Vinothkumar et al. [11] for investigating and comparing influence of cryogenically cooled copper electrode and conventional electrode. For cryogenic cooling, liquid nitrogen (LN₂) is used. Grey relational analysis (GRA) has been used for optimizing the process framework, and result shows that cryogenic cooling gives increased efficiency. Majumder [12] has conducted experiments on AISI 316LN stainless steel for optimizing the process parameters in EDM process. Researchers have made fuzzy model to provide fitness function and finally used particle swarm optimization (PSO) for optimizing multiobjective function. Teimouri and Baseri [13] presented a novel model for removing the debris from tool–workpiece interface by using a rotary tool assisted with rotary magnetic field.

Shabgard et al. [14] investigated the influence of process parameters of AISI H13 tool steel work piece and AISI H13 steel tool. The research has shown that the controlling of processes parameters can considerably reduce TWR. The significance of operational parameters on machining performances of EDM has been studied by Huang et al. [15]. Central composite design has been used with different input process responses and two output parameters [16]. Analysis of variance has been utilized for investigating most important process measures in this process. In the aforementioned work, different flushing methods have been used for conducting experiments.

GRA combined with principal component analysis (PCA) has been applied by Jadish et al. [17] to evaluate and optimize the EDM performance characteristics. PCA-​weighted components corresponding to the performance measures are first evaluated, and then by applying GRA, the process has been optimized. Most significant factor among the process parameters is determined by analysis of variance (ANOVA). Instead of conventional Response Surface Methodology (RSM) model, Xuan-​Phuong Dang [18] has used Kriging model for creating nonlinear equations related to MRR and tool wear with standard input parameters in CNC EDM of P20 steel. Then, PSO has been used for optimizing this multiobjective optimization problem. It is also proved that this method is successful for other types of applications. A new approach of optimization known as Neuro-​Grey method of optimization has been presented by Panda [19] and Tripathy and Tripathy [20] in EDM. In this process, commercial grade oil is used as dielectric, and SiC powder is used as an additive. This attempt has been proved to be very successful. Manivannan and Pradeep Kumar [21] have conducted drilling of mic...

Table of contents

• Cover
• Half Title
• Series Page
• Title Page
• Copyright Page
• Table of Contents
• Preface
• Editors
• Contributors
• Chapter 1 A Critical Review on the Machining of Engineering Materials by Die-​Sinking EDM
• Chapter 2 Optimization of Machining Parameters of High-​Speed Toolpath to Achieve Minimum Cycle Time for Ti-​6Al-4V
• Chapter 3 A Review of Machinability Aspects of Difficult-​to-Cut Materials Using Microtexture Patterns
• Chapter 4 Micromachining
• Chapter 5 A Review Study on Miniaturization—A Boon or Curse
• Chapter 6 A Comprehensive Review on Similar and Dissimilar Metal Joints by Friction Welding
• Chapter 7 3D Bioprinting in Pharmaceuticals, Medicine, and Tissue Engineering Applications
• Chapter 8 Investigating on the Lapping and Polishing Process of Cylindrical Rollers
• Chapter 9 NiTi Thin-​Film Shape Memory Alloys and Their Industrial Application
• Chapter 10 Carbon Fibers: Surface Modification Strategies and Biomedical Applications
• Index