SiC based composites filled with graphene nano-platelets (GNPs) or graphene oxide (GO) prepared by rapid hot-pressing exhibit sufficient electrical conductivity for their machinability by wire ...electro-discharge machining (WEDM). Composites microstructure anisotropy caused by graphene alignment as a consequence of rapid hot pressing was confirmed by measuring of electrical conductivity and thermal diffusivity. Electrical conductivity increased significantly with increased weight fraction of graphene in both measured directions. Highest value of 2031 S/m was obtained for composites with 15 wt. % of GNPs in parallel direction and only 1246 S/m in perpendicular direction to aligned GNPs. Thermal diffusivity is 63.3 mm2/s in parallel and only 23.3 mm2/s in perpendicular direction. The increase of the electrical conductivity has resulted in successful WEDM. The MRR was almost doubled when the filler concentration increased from 5 wt. % GNPs/GO to 15 wt. % GNPs. At the same time, the surface roughness decreased.
Conventional machining of titanium matrix composite (TMC) is very intricate for its superior strength-to-weight ratio and resistance to fatigue and corrosion. The novelty lies in the analysis of ...multi-objective genetic algorithm (MOGA) coupled with desirability, forming desirable multi-objective genetic algorithm (DMOGA) of wire electro-discharge machining (WEDM) machining characteristics of performance measures varying power (P), peak current (IP) and time-off (Toff). In this paper, investigation is carried on design of experiments (DOE) on performance measures like material removal rate (MRR), surface roughness (SR), kerf width (KW) and over cut (OC) and reasonable results are attained and authenticated by confirmatory test. Optimality is attained when P is 7.37 W, Toff is 27.87 µs, IP is 9.71 A, MRR is 3.61 mm3/min, SR is 1.39 µm, KW is 0.35 mm, OC is 0.09 mm and combined desirability is 0.72.
Wire electrical discharge machining (WEDM) is a particular thermal non-contact technique of machining. Within the past decade, the WEDM process is a competitive and economical machining option ...fulfilling the demanding machining requirements from a mere tool to complex die making process. Now a day’s WEDM process is commonly used for machining of materials from conventional materials to nascent materials like Metal Matrix Composites, ceramic composites, which have vast applications in automobile, aircraft, railway sectors, defence, aerospace, micro systems industries, agriculture farm machinery, etc. Metal matrix composites (MMCs) are advanced materials having properties such as light weight, high specific strength, good wear resistance, a low thermal expansion coefficient, low density. These materials can be machined by non-conventional methods like water jet, laser cutting but these processes are restricted to linear cutting only. Wire Electrical discharge machining (WEDM) shows higher ability for cutting complex shapes with high precision for MMCs. Conventional machining of MMC’s causes serious tool wear due to greater hardness and the existence of abrasive reinforcement particles. Numerous studies and research are going on in modelling of WEDM since its inception. Most of the researchers thoroughly worked on process modelling, process parameters, materials of electrodes/tool-work-piece, dielectric medium, etc. The process modelling of WEDM is considered as prime objective. There is need to categorize the variety of research for better understanding of research done in this area. This paper reviews machining of MMCs, techniques used, responses, findings and summery of review. The paper also discusses the future trends of research work in the same area.
Investigating the effect of process parameters on material removal rate and surface roughness is very important for process planing in wire electro-discharge machining. In this study, wire ...electro-discharge machining of cementation alloy steel 1.7131 is experimentally studied, then linear regression model and feedforward backpropagation neural network were established to predict surface roughness and material removal rate for effective machining. The full factorial experiment was chosen for experiments. Experiments were performed under different cutting conditions of pulse current, frequency of pulse, wire speed, and servo speed. The optimized neural network with the best performance for prediction had eight neurons in the hidden layer, capability with 0.773 % overall mean prediction error, while 2.547 % errors was revealed by regression model. Totally, the comparison of the results showed that the neural network is more robust with better accuracy.
Wire electric discharge machining (WEDM) is an important non-traditional manufacturing technique for industries processing hard-to-machine materials. It can produce complex shapes with high ...dimensional accuracy and surface finish. Ti6Al4V is frequently used in biomedical applications such as surgical implants, dentistry, and orthopedic wires. All these applications require machining complex profiles with high accuracy in terms of dimensions and surface properties. Multi-pass machining is a proven technique for minimizing the damage on the machined surface but increasing the number of passes lowers the productivity. Hence, careful selection of wire offset value for trim cutting is crucial to maintain process efficiency and keep the number of passes minimum. The objective of this study is to investigate the effect of wire offset in multi-pass machining on surface integrity, dimensional accuracy, and cutting speed in complex WEDM of Ti6Al4V and limit the number of trim passes to one. In addition, effect of electrode composition on machining responses is studied for three different types of wires (uncoated brass, Broncocut-W, and Topas Plus X). Experimental results indicate that a single trim cut at an offset value of 0.11mmprovides better surface finish and minimum recast layer. Surface roughness of 1.31 µm is obtained using brass wire: 16.5% and 18.6% less than for Broncocut-W and Topas plus X, respectively. Similarly, recast layer of 8.183 µm attained by brass wire is smaller than 8.98 µm, and 10.041 µm produced by the other wires. The uncoated brass wire has proved to be the best electrode for surface finish, recast layer thickness, and dimensional accuracy of the machined profile. However, Bronococut-W wire has performed better in terms of cutting speed.
The AISI D2 tool steel are the material that for machining of heat treated AISI D2 tool steel, a highly developed method must be employed. Due to exceptional thermo-mechanical properties and superior ...wear resistance AISI D2 tool steel are finding widespread applications in a lot of manufacturing industries. WEDM is one of the highly developed and sophisticated methods for making of intricate shapes and convoluted details as required for dies and punches. For efficient machining, the need of optimization and appropriate choices of process parameters such as Material Removal Rate and Surface Roughness is utmost goal.
In conventional wire electrical discharge machining (WEDM), WC-Co machined pieces can stay for hours in the worktank. In the pH range of the dielectric Co actively dissolves and thus corrosion can ...occur affecting the mechanical properties and lifetime of those pieces. This study demonstrates how applying cathodic polarization through the implementation of auxiliary electrodes in the work zone helps reducing in-depth propagation of the corrosion attacks on WC-Co hardmetals during storage in the dielectric. Our experimental findings were supported by a prediction model that helps visualizing the electrical field distribution during machining and storage and identifying the critical engineering parameters.
The machining precision and its consistency of turbine disk fir-tree slots have a direct influence on the performance of aero-engine rotor components. However, the structural dimensions of fir-tree ...slot are small, and the cutting performance of materials is extremely poor, which lead to great difficulty in machining and very few available machining methods. With the application of new materials in the aero-engines, the machining precision and quality requirements of fir-tree slots are further improved. Therefore, many research achievements on the high-efficiency, high-quality and low-cost machining technology of turbine disk fir-tree slots have been obtained. By summarizing and classifying the machining methods of aero-engine turbine disk fir-tree slots, a brief review on the characteristics of different methods are presented in detail, which provide a reference for selecting the appropriate machining method of turbine disk fir-tree slots in the field of aviation manufacturing. Meanwhile, combined with the research and application status of machining technology of turbine disk fir-tree slots, it is presented that multi-process compound machining is an effective method to realize high-efficiency, high-quality and low-cost precision machining of turbine disk fir-tree slots, such as wire electro discharge machining (wire-EDM) and profiled grinding, wire electrochemical machining (wire-ECM) and profiled grinding, wire-EDM and broaching, milling and broaching.
The second volume of the Special Issue on “Micro-Electro Discharge Machining: Principles, Recent Advancements and Applications” confirms the growing interest in the micro-EDM technology as a suitable ...and efficient technology for machining novel, multilateral components, with demanding requirements in terms of precision, accuracy, and productivity.This volume consists of 10 original research papers which involve several approaches to micro-EDM and cover the enhancement of the process performance, such as the material removal rate, surface roughness, or machining accuracy, using advanced optimization methods. Some studies also consider several dielectric fluid additives and investigate the processability of new materials. Others investigate the combination of Reverse-micro-EDM with laser beam micromachining or explore new applications for the micro-EDM for fabricating antimicrobial nanosilver colloid.
Titanium matrix composite (TMC) is expansively used in different aerospace, biomedical and automobile industries due to its exceptional strength and resistant properties. This manuscript aims to ...provide the current state-of-art of enhancement of these tribo-mechanical properties by development of a novel TMC through laser engineering net shaping (LENS) process, possessing Young's modulus (550 GPa), co-efficient of thermal expansion (8.6 × 10−6/K), hardness (396 HV), yield strength in compression (945–1020 MPa), ultimate compressive strength (1020–1096 MPa) and elongation (25–32.5%), thus depicting the microstructure with an excellent interfacial bonding of TiB2 with Ti. A novel optimization algorithm is proposed termed as desirable grey relational analysis (DGRA). Here, the predicted responses obtained from desirability function are further analyzed with the experimental results obtained from wire electro-discharge machining (WEDM), varying power (P), time off (Toff) and peak current (IP), using grey relational analysis. The results are then compared with fuzzy technique for order preference by similarity to ideal solution (FTOPSIS) coupled with fuzzy analytical hierarchy process (FAHP) for criteria weights. Response surface methodology (RSM) is carried on the output performance measures like material removal rate (MRR), surface roughness (SR), kerf width (KW) and over cut (OC), and authenticated by confirmatory tests. Optimized value is improved by 3.09% when compared with desirability to FTOPSIS, 2.05% when evaluated with FTOPSIS to DGRA, and 1.02% when contrasted with desirability to DGRA.
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