Investigation of the Machinability of the Inconel 718 Superalloy during the Electrical Discharge Drilling Process

The properties of the Inconel 718 superalloy are used in the manufacturing of aircraft components; its properties, including high hardness and toughness, cause machining difficulties when using the conventional method. To circumvent this, non-conventional techniques are used, among which electrical discharge machining (EDM) is a good alternative. However, the nature of removing material using the EDM process causes the thermophysical properties of Inconel 718 to hinder its machinability; thus, a more extensive analysis of the influence of these properties on the EDM process, and a machinability analysis of this material in a wider range, using more process parameters, are required. In this study, we investigated the drilling of micro-holes into the Inconel 718 superalloy using the EDM process. An experiment was conducted to evaluate the impact of five process parameters with a wide range of values (open voltage, time of the impulse, current amplitude, the inlet dielectric fluid pressure, and tube electrode rotation) on the process’s performance (drilling speed, linear tool wear, the side gap thickness, and the aspect ratio of holes). The analysis shows that the thermal conductivity of this superalloy significantly influences the effective drilling of holes. The combination of a higher current amplitude (I ≥ 3.99 A) with an extended pulse time (ton ≥ 550 µs) can provide a satisfactory hole accuracy (side gap thickness ≤ 100 µm), homogeneity of the hole entrance edge without re-solidified material, and a depth-to-diameter ratio of about 19. Obtaining a high dimensional shape accuracy of holes has an enormous effect on their usability in the structure of the components in the aviation industry.

Download Full-text

Investigation of the Spark Cycle Effect on Material Removal Rate in Wire Electrical Discharge Machining

Manufacturing ◽

10.1115/imece2003-41850 ◽

2003 ◽

Author(s):

Scott F. Miller ◽

Albert J. Shih

Keyword(s):

Process Parameters ◽

Material Removal Rate ◽

Electrical Discharge ◽

Material Removal ◽

Electrical Discharge Machining ◽

Removal Rate ◽

Short Circuit ◽

Wire Electrical Discharge Machining ◽

Time Duration ◽

Edm Process

The development of new, advanced engineering materials and the needs for precise and flexible prototype and low-volume production have made wire electrical discharge machining (EDM) an important manufacturing process to meet such demand. This research investigates the effect of spark on-time duration and spark on-time ratio, two important EDM process parameters, on the material removal rate (MRR) and surface integrity of four types of advanced material: porous metal foams, metal bond diamond grinding wheels, sintered Nd-Fe-B magnets, and carbon-carbon bipolar plates. An experimental procedure was developed. During the wire EDM, five types of constraints on the MRR due to short circuit, wire breakage, machine slide speed limit, and spark on-time upper and lower limits have been identified. An envelope of feasible EDM process parameters is created and compared across different work-materials. Applications of such process envelope to select process parameters for maximum MRR and for machining of micro features are presented.

Download Full-text

A Multiobjective Genetic-Algorithm-Based Optimization of Micro-Electrical Discharge Drilling

Research Anthology on Multi-Industry Uses of Genetic Programming and Algorithms ◽

10.4018/978-1-7998-8048-6.ch035 ◽

2021 ◽

pp. 676-698

Author(s):

Deepak Rajendra Unune ◽

Amit Aherwar

Keyword(s):

Genetic Algorithm ◽

Process Parameters ◽

Inconel 718 ◽

Electrical Discharge ◽

Electrical Discharge Machining ◽

Removal Rate ◽

Machining Processes ◽

Micro Electrical Discharge Machining ◽

Electrical Discharge Drilling ◽

Machining Rate

Inconel 718 superalloy finds wide range of applications in various industries due to its superior mechanical properties including high strength, high hardness, resistance to corrosion, etc. Though poor machinability especially in micro-domain by conventional machining processes makes it one of the “difficult-to-cut” material. The micro-electrical discharge machining (µ-EDM) is appropriate process for machining any conductive material, although selection of machining parameters for higher machining rate and accuracy is difficult task. The present study attempts to optimize parameters in micro-electrical discharge drilling (µ-EDD) of Inconel 718. The material removal rate, electrode wear ratio, overcut, and taper angle have been selected as performance measures while gap voltage, capacitance, electrode rotational speed, and feed rate have been selected as process parameters. The optimum setting of process parameters has been obtained using Genetic Algorithm based multi-objective optimization and verified experimentally.

Download Full-text

Influence of EDM process parameters in deep hole drilling of Inconel 718

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-007-1084-y ◽

2007 ◽

Vol 38 (1-2) ◽

pp. 74-84 ◽

Cited By ~ 176

Author(s):

P. Kuppan ◽

A. Rajadurai ◽

S. Narayanan

Keyword(s):

Process Parameters ◽

Inconel 718 ◽

Hole Drilling ◽

Deep Hole ◽

Deep Hole Drilling ◽

Edm Process

Download Full-text

On the Influence of Electrical Discharge Drilling Parameters and Per-formance Measures of Inconel 718 Superalloy - a Study

Mechanika ◽

10.5755/j02.mech.25444 ◽

2021 ◽

Vol 27 (6) ◽

pp. 483-491

Author(s):

Jayaraj JEEVAMALAR ◽

Sundaresan RAMABALAN ◽

Jayaraj JANCIRANI

Keyword(s):

Inconel 718 ◽

Electrical Discharge ◽

Removal Rate ◽

Experimental Results ◽

Drilling Process ◽

Machining Parameters ◽

Characteristic Analysis ◽

Peak Current ◽

Electrical Discharge Drilling ◽

The Impact

In order to achieve higher productivity and product quality, the investigation of machining parameters on Electrical Discharge Drilling and surface characteristic analysis are most critical for manufacturing industries. The intention of this article is to assess the impact on performance matrices including Material Removal Rate, and Surface Roughness of input factors of peak current, pulse-on and off duration while drilling with a rotary hollow copper tool on Inconel 718 under Tungsten powder suspended kerosene. Analysis of Variance has been implemented using MINITAB release 18 software to identify the most significant input factors. An Artificial Neural Network was used for validating the experimental results of the drilling process. The additional intention of this research is to discover the significance of influencing input parameters and analyze the quality surface of the workpiece were observed by microscope tests. The experimental results indicated that the peak current and pulse-on period have an effect on the performance of the drilling process considerably.

Download Full-text

Selective Laser Melting of the Inconel 718 Nickel Superalloy

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.698.333 ◽

2014 ◽

Vol 698 ◽

pp. 333-338 ◽

Cited By ~ 6

Author(s):

Vadim Sh. Sufiiarov ◽

Evgenii V. Borisov ◽

Igor A. Polozov

Keyword(s):

Selective Laser Melting ◽

Process Parameters ◽

Inconel 718 ◽

Melting Process ◽

Nickel Superalloy ◽

Mechanical Tests ◽

Laser Melting ◽

Influence Of Process Parameters ◽

Inconel 718 Superalloy

The results of the research on selective laser melting process of the Inconel 718 superalloy powder under conditions of additive manufacturing of parts for special purposes are presented. The influence of process parameters on the quality of manufactured parts is shown. Process parameters which allow manufacturing parts with the density close to 100%, are determined. Also, the results of mechanical tests and investigation of microstructure are presented.

Download Full-text

Impact of the Deionized Water on Making High Aspect Ratio Holes in the Inconel 718 Alloy with the Use of Electrical Discharge Drilling

Materials ◽

10.3390/ma13061476 ◽

2020 ◽

Vol 13 (6) ◽

pp. 1476 ◽

Cited By ~ 4

Author(s):

Magdalena Machno ◽

Rafał Bogucki ◽

Maciej Szkoda ◽

Wojciech Bizoń

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Inconel 718 ◽

Electrical Discharge ◽

Initial Temperature ◽

Deionized Water ◽

Working Fluid ◽

Inconel 718 Alloy ◽

Electrical Discharge Drilling ◽

Side Gap

Nickel-based superalloys are being increasingly applied to manufacture components in the aviation industry. The materials are classified as difficult-to-machine using conventional methods. Nowadays, manufacturing techniques are needed to drill high aspect ratio holes of above 20:1 (depth-to-diameter ratio) in these materials. One of the most effective methods of making high-aspect-ratio holes is electrical discharge drilling (EDD). While drilling high aspect ratio holes, a crucial issue is the flushing of the gap area and the evacuation of the erosion products. The use of deionized water as the dielectric fluid in the EDD offers a considerable potential. This paper includes an analysis of the influence of the machining parameters (pulse time, current amplitude and discharge voltage) on the process performance (drilling speed, linear tool wear, taper angle, hole’s aspect ratio, side gap thickness), during the EDD with the use of deionized water in the Inconel 718 alloy. The obtained through holes were subjected to the extended analysis. The impact of the initial working fluid temperature and pressure on the conditions of the flow through the electrode channel was also subjected to the analysis. The deionized water properties were changed by applying an initial temperature. Based on the results of an analysis of the previous research, the EDD of the through holes was performed for a pre-set initial temperature (~313.15 °K) and initial pressure of the working fluid (8 MPa) and selected process parameters. An analysis of the results indicates increasing of hole’s aspect ratio by about 15% (above 30), decreasing the side gap thickness by about 40% and enhanced surface integrity.

Download Full-text