Investigations on Machining Aspects of Inconel 718 During Wire Electro-Discharge Machining (WEDM): Experimental and Numerical Analysis

Wire electro- discharge machining (WEDM) is known as unique cutting in manufacturing industries, especially in the good tolerance with intricate shape geometry in die industry. In this study the workpiece has been chosen as Inconel 718. Inconel 718 super alloy is widely used in aerospace industries. This nickel based super alloy has excellent resistance to high temperature, mechanical and chemical degradations with toughness and work hardening characteristics materials. Due to these properties, the machinability studies of this material have been carried-out in this study. The machining of Inconel 718 using variation of wire electrode material (brass wire electrode and zinc coated brass wire) with diameter equal to 0.20mm has been carried out. The objective of this study is mainly to investigate the various WEDM process parameters and performance of wire electrodes materials on Inconel 718 with various types of cutting. The optimal process parameter setting for each of wire electrode material has been obtained for multi-objective response. The kerf width, Material Removal Rate (MRR) and surface finish, corner error, corner deviation and angular error are the responses which are function of process variables viz. pulse-on time, discharge current, wire speed, flushing pressure and taper angle. The non-linear regression analysis has been developed for relationship between the process parameter and process characteristics. The optimal parameters setting have been carried out using multi-objective nature-inspired meta-heuristic optimization algorithm such as Whale Optimization Algorithm (WOA) and Gray Wolf Optimizer (GWO). Lastly numerical model analysis has been carried out to determine MRR and residual stress using ANSYS software and MRR model validated with the experimental results. The overlapping approach has been adopted for solving the multi-spark problem and validate with the experimental results

Experimental and Numerical Analysis of Angular Error in Taper Cutting Using Wire Electrical Discharge Machining

Today, there are far greater demands for higher precision in machining, use fewer tools and ease of operation. Wire electro discharge machining (WEDM) is one, mostly acceptable non-conventional machining processes, using fewer tools; ease machining and producing extreme accurate shapes in hard materials those using in the tooling industry where the extreme precision is required and complexly determines such as extrusion dies in wear-resistant materials, cutting dies, etc. Wire EDM Taper cutting took forward the generation of inclined ruled surfaces, and it is eminently more important in the manufacturing of tooling requiring draft angles. The required angle is reached by applying a relative moment between the lower guide and the upper guide. Deformation arises in the wire, during the machining of taper cutting using Wire EDM. Due to that deformation in the wire, effected to the ruled inclination of machined parts. Such circumstances cause a dimensional error, loss of tolerances and less precision that can prime to the rejection of high added value tooling. To predict the deformation of wire by considering contact mechanics, properties of wire, properties of the guide, boundary conditions, typically used in taper cutting operations, has been taking into the account. FEM is needed to reduce the experimental cost and lack of time consumption and to give a more common approach to the problem. Finite Element Model (FEM) has been used to find out the deformation occurs during wire EDM process by changing the wire parameters like wire tension, wire diameter, taper angle and wire length, which is generally considering in taper cutting. This result intends to give you better understanding shows that taper angle and wire length are the most effective parameters in taper cutting process. Taguchi’s L16 orthogonal array is used to reduce the experimental runs. Traditional Taguchi approach is insufficient to solve a multi-response optimization problem. In order to overcome this limitation, utility theory has been implemented, to convert multi-responses into single equivalent response called overall utility index. Both the results, FEM and experimental have been checked

Latest Developments in Industrial Hybrid Machine Tools that Combine Additive and Subtractive Operations

Hybrid machine tools combining additive and subtractive processes have arisen as a solution to increasing manufacture requirements, boosting the potentials of both technologies, while compensating and minimizing their limitations. Nevertheless, the idea of hybrid machines is relatively new and there is a notable lack of knowledge about the implications arisen from their in-practice use. Therefore, the main goal of the present paper is to fill the existing gap, giving an insight into the current advancements and pending tasks of hybrid machines both from an academic and industrial perspective. To that end, the technical-economical potentials and challenges emerging from their use are identified and critically discussed. In addition, the current situation and future perspectives of hybrid machines from the point of view of process planning, monitoring, and inspection are analyzed. On the one hand, it is found that hybrid machines enable a more efficient use of the resources available, as well as the production of previously unattainable complex parts. On the other hand, it is concluded that there are still some technological challenges derived from the interaction of additive and subtractive processes to be overcome (e.g., process planning, decision planning, use of cutting fluids, and need for a post-processing) before a full implantation of hybrid machines is fulfilledSpecial thanks are addressed to the Industry and Competitiveness Spanish Ministry for the support on the DPI2016-79889-R INTEGRADDI project and to the PARADDISE project H2020-IND-CE-2016-17/H2020-FOF-2016 of the European Union's Horizon 2020 research and innovation program

Multi-Objective Optimization of Input Machining Parameters to Machined AISI D2 Tool Steel Material

Poor surface finish on die and mould transfers the bad quality to processed parts. High surface roughness is an example of bad surface finish that is normally reduced by manual polishing after conventional milling machining process. Therefore, in order to avoid disadvantages by manual polishing and disadvantage by the machining, a sequence of two machining operations is proposed. The main operation is run by the machining and followed by Rotary Ultrasonic Machining Assisted Milling (RUMAM). However, this sequence operation requires optimum input parameters to generate the lowest surface roughness. Hence, this paper aims to optimize the input parameters for both machining operations by three soft-computing approaches – Genetic Algorithm, Tabu Search, and Particle Swarm Optimization. The method adopted in this paper begins with a fitness function development, optimization approach usage and ends up with result evaluation and validation. The soft-computing approaches result outperforms the experiment result in having minimum surface roughness. Based on the findings, the conclusion suggests that the lower surface roughness can be obtained by applying the input parameters at maximum for the cutting speed and vibration frequency, and at minimum for machining feed rate. This finding assists manufacturers to apply proper input values to obtain parts with minimum surface roughness

Micro-Electro Discharge Machining: Principles, Recent Advancements and Applications

Micro electrical discharge machining (micro-EDM) is a thermo-electric and contactless process most suited for micro-manufacturing and high-precision machining, especially when difficult-to-cut materials, such as super alloys, composites, and electro conductive ceramics, are processed. Many industrial domains exploit this technology to fabricate highly demanding components, such as high-aspect-ratio micro holes for fuel injectors, high-precision molds, and biomedical parts.Moreover, the continuous trend towards miniaturization and high precision functional components boosted the development of control strategies and optimization methodologies specifically suited to address the challenges in micro- and nano-scale fabrication.This Special Issue showcases 12 research papers and a review article focusing on novel methodological developments on several aspects of micro electrical discharge machining: machinability studies of hard materials (TiNi shape memory alloys, Si3N4–TiN ceramic composite, ZrB2-based ceramics reinforced with SiC fibers and whiskers, tungsten-cemented carbide, Ti-6Al-4V alloy, duplex stainless steel, and cubic boron nitride), process optimization adopting different dielectrics or electrodes, characterization of mechanical performance of processed surface, process analysis, and optimization via discharge pulse-type discrimination, hybrid processes, fabrication of molds for inflatable soft microactuators, and implementation of low-cost desktop micro-EDM system

advanced sensor signal feature extraction and pattern recognition for wire edm process monitoring

Wire electrical discharge machining (WEDM) is investigated in the perspective of zero-defect manufacturing with the scope to detect anomalous process conditions leading to typical defects generated during WEDM, i.e. the occurrence of lines and marks on the resulting workpiece surface. A multiple sensor monitoring system is employed to acquire high sampling rate sensorial data relative to signals of voltage and current in the gap between workpiece and wire electrode. An advanced signal processing methodology is implemented to extract and select the most relevant features useful to identify the undesired process conditions through a cognitive pattern recognition paradigm. (C) 2016 The Authors. Published by Elsevier B.V

Parameter Optimization On Hybrid Micro Wire Electrical Discharge Turning

Micro-machining is expected to play an important role in today's manufacturing technology. However, the traditional down-scaling process creates challenges relating to process stability and materials behaviour especially for small difficult-to-machine made materials. Therefore, a suitable material removal process to perform micro-machining on cylindrical components is spark erosion process. In this study, the new hybrid micro-machining process is developed. This process is synonym with the name of wire electrical discharged turning (WEDT) which incorporates a turning process of rotating workpiece to continuous travelling electrode wire in electrical discharged conditions produced by wire electrical discharge machine. The objective of this research is to develop and evaluate the advance machinery and equipment for rotary axis mechanism that is being used to rotate the workpieces. The research focuses on optimizing the process parameter of hybrid WEDT for micro-machining straight shaft cylindrical component made of Ti6Al4V as materials. The issues pertaining to hybrid WEDT process on surface roughness (Ra) in the past have been explored comprehensively. The rotary axis mechanism that works well with WEDM machine has been successfully developed and the micro turning operations has been performed. The parameter optimization consideration on Ra begins with two stage screening. Firstly, the suitable combination parameter and its range is properly selected. Then, the selection of appropriate parameters and range is further screened by Taguchi orthogonal array L12. From the 11 process parameters that consist of electrical, non-electrical and rotary axis mechanism characteristics, only four has been selected to perform optimization by response surface methodology (RSM) which are intensity of pulse, voltage open, wire tension and rotational spindle speed. The other parameters are fixed at best level to produce low Ra value which is identified by Alicona Infinite Focus microscope (IFM). The optimal Ra that is produced by experiment through desirability approach is as much as 4.0143 μm with relative error as much as 5.9% compared to the prediction. The parameter and its level are pulse intensity of 8 Notch, wire tension of 14.8 Newton, voltage of 7 Notch and rotational spindle speed of 2390 rev/min. The machined parts surface is being deteriorated accordingly to the violent energy density generated by high pulse intensity and voltage, low wire tension and spindle speed