Improvement In Material Removal Rate Research Articles

Effects of tool rotation and powder abrasive on EDM performance of H13 tool steel

The present work reports an experimental study on the performance of rotary electro-discharge machining (REDM) on H13 tool steel using rotary copper electrode in the presence of abrasives. Machining performance was evaluated in terms of machining rate and surface roughness. Experiments were conducted with peak current, speed of electrode rotation, concentration of abrasive and pulse on time as process variables. Taguchi methodology was adopted for experimental design. Analysis of variance (ANOVA) was performed to investigate the influence of input parameters on material removal rate (MRR) and surface roughness (SR). This work introduces a new method abrasive mixed REDM of improving machining performance vis. rotation of tool in presence of abrasives. Results indicated that giving rotation to EDM tool results in considerable improvement in MRR and SR. This method successfully removed the debris from the machining area which was one of the major challenges in the existing process and major cause of rough surface due to inactive pulses. It was confirmed experimentally that material removal rate increased by 25.53% and surface roughness decreased by 21.22%.

Improving quartz micro-machining performance by magnetohydrodynamic and zinc-coated assisted traveling wire-electrochemical discharge machining process

In this industrial revolution era, machining of advanced non-conducting material like quartz is difficult and costly with existing conventional machining processes. Further its high hardness, brittleness and non-conducting nature add-up to machining difficulties. Traveling Wire-electrochemical discharge machining (TW-ECDM) process has a good potential of machining of quartz material. TW-ECDM process is a hybrid and complex combination of electrochemical machining (ECM) and wire-electrical discharge (W-EDM) machining process. However, due to poor electrolysis process, sparking phenomenon is not steady and uniform at higher machining depth. In the present work, the authors have tried to investigate the feasibility of Magnetohydrodynamic (MHD) assisted TW-ECDM process for machining of quartz. This MHD approach produces the magnetic field which helps to improve the electrolysis process, accuracy, and efficiency. Also, first-time zinc-coated brass wire of diameter 0.15 mm has been used to improve the machining performance. A hybrid approach of Taguchi robust design and ANOVA was used to analyze the process performance. Experimental results reveal that the MHD approach enhances the material removal rate (MRR) and reduces the surface rousghness (Ra) as compared to without MHD approach. The improvement in MRR was found from 25.35% to 83.72% and Ra reduced from 9.06% to 28.79%/ Additionally, an experimental result shows that quartz machined by TW-ECDM with MHD approach yielded longer and straight machined cut with less kerf width. Henceforth, the proposed hybrid MHD and zinc-coated brass wire approach is simple, easy, economically viable, environmental friendly and does not require any major changes in the existing machining setup. Moreover, the length of cut, kerf width and machine profile were also analyzed by scanning electron microscope.

A comparative study for biomachining of aluminium alloy 4004 using Acidithiobacillus ferrooxidans and Aspergillus niger

Biomachining is one of the fastest growing technologies in the coming future. Besides, there are many advantages of biomachining such as low energy consumption, environmental friendly and no use of coolant; some of the shortcomings reported by early researchers is less metal removal rate. In this work, a comparative study on biomachining of aluminium alloy 4004 has been done using Acidithiobacillus ferrooxidans and Aspergillus niger. Taguchi design of experiments (DOE) L16 approach is used to analyse the influence of process parameters (shaking rate, pH, time and concentration) to enhance the performance of biomachining. Thus, based on the analysis of results, it has been concluded that Acidithiobacillus ferrooxidans provides better results in comparison to Aspergillus niger. Additionally, optimal values of process parameters have been suitably compared in case of both bacteria and fungus for improved material removal rate, surface finish and hardness.

Experimental investigation and process parameters optimization of stir cast aluminium metal matrix composites to improve material removal rate

In industrial applications, Metal Matrix Composites (MMCs) play an imperative role for making any new components. Due to its exceptional characteristics, it is regularly use in many applications such as automobile, agriculture, medical, electrical and electronic fields. Due to its various elements are using to develop composites high hardness will increase, it is difficult to machine by conventional process. Aluminium Metal Matrix Composites (AMMCs) is considered as a work material which has admirable properties such as strength, hardness, ductility and better corrosive resistance. Stir casting technique is chosen for fabricate the aluminium metal matrix composites. The pressure of water, stand of distance and flow rate of abrasive are chosen as process parameters to check machinability of materials. L9 orthogonal array is used to identify minimum number of trails to test the removal rate material of AMMCs. In this machining process, Water jet machining of abrasive is used to machine the aluminium metal matrix and responses such as removal rate of material is measured by the input parameters. Analysis of machinability characteristics is done and parametric optimization are to be completed through Taguchi method.

Powder additives influence on dielectric strength of EDM fluid and material removal

Electrical discharge machining (EDM) is used to machine difficult-to-machine materials having high hardness and toughness. One of the recent advancements in the EDM process is the powder mixed electrical discharge machining (PMEDM) process, in which the metallic or abrasive additives in the form of fine powders are added to the dielectric fluid. PMEDM was found to improve machinability in terms of higher material removal rate (MRR) and enhanced tool wear index (TWI), by reducing the breakdown strength of the dielectric. In PMEDM process, machining happens with relatively larger spark gap with enhanced machining characteristics. This paper investigates the influence of powder mixing on the breakdown strength of the liquid dielectric and the gap voltage. Determination of dielectric strength was carried out with a specially designed experimental set-up adhering to ASTM standard D1816 - 97. Tests were conducted using silicon carbide, alumina, copper and aluminium powders. The effect of varying the grain size was also studied. An experimental set-up was also designed and realised to measure the influence of powder mixing on the gap voltage and MRR in machining of titanium alloy. The results have shown significant improvement in MRR and TWI.

Multi objective optimization of CNC turning process parameters with Acrylonitrile Butadiene Styrene material

Apart from moulding process, the plastics are required to be machined in many occasions so as to impart required dimensional accuracy. The turning operations of plastic materials pose challenges owing to its inherent problems in imparting required Surface Roughness (SR) and improved Material Removal Rate (MRR). High performance Acrylonitrile Butadiene Styrene (ABS) material has been chosen in the proposed work to study its machinability under turning operation. It is widely used in the home appliances, safety helmets and interiors of automotive because of their flexible structural characteristics. The various influencing factors like Spindle Speed (SS), Feed Rate (FR), and Depth of Cut (DOC) related with turning process are considered in L16 orthogonal array experimental plan in order to optimize them to achieve better values for SR and MRR. The samples of ABS have been turned using CNC machine by setting the input parameters at various levels and the corresponding output responses have been predicted. The MINITAB-18 software is employed to predict the optimal parameter setting with the results obtained from the Grey Relational Analysis (GRA). Further, Regression Analysis (RA) is employed using Design Expert Software to form the equation connecting input and output responses. The results of GRA suggested the best combination of process parameters with respect to SR and MRR.

Improvement of the machining characteristics in WEDM based on specific discharge energy and magnetic field–assisted method

This paper is aimed at investigating and improving material removal rate (MRR) and surface quality in wire electrical discharge machining (WEDM) based on specific discharge energy and magnetic-assisted method. A set of a single-factor experiment is implemented to analyze the effects of carbon content and discharge parameters on machining characteristics. The concept of specific discharge energy (SDE) is proposed to reveal the fundamental influence of workpiece material properties on material removal rate and to obtain the optimal machining feed rate. The mathematical model between SDE and the physical properties of workpiece material is also fitted out. Additionally, it can be found that, in subsurface material, the recast layer is with the maximal hardness followed by bulk material and heat-affected zone. Ra and RLT firstly increase and then decrease with the increase of carbon content, and they have a positive correlation with discharge peak current and pulse-on time. Finally, verified experiment shows that, comparing with other machining feed rates, the method of optimal machining feed rate according to SDE can simultaneously achieve the fastest actual machining speed and the lowest surface roughness. In addition, the method of magnetic-assisted trim cutting can almost eliminate recast layer and reduce heat-affected zone to less than 20 μm.

EDM-drilling Characteristics with the Rotation Motion of SS304

This investigation presents an attempt to explore a novel rotary electrical discharge cutting process for high processing quality of work-piece and a hard-to-machine work-piece. An experiment was carried out on SS304 with rational work-piece and new electrode of slot on outer-side surface. Processing quality of work-piece in condition described above is superior to that in the traditional EDM in terms of shape and roughness. The result is attributed to the mixing effect of high probability of normal discharge and speed of electrolyte flow, resulting into good transport efficiency of chip, finally bringing into machining phenomenon with characteristics of high frequency and small removal. The result from compared experiments is promising for manufactures and engineers to improve material removal rate in traditional EDM.

Self-Flushing in EDM Drilling of Ti6Al4V Using Rotating Shaped Electrodes.

This article reports an experimental investigation of the efficacy of self-flushing in the Electrical Discharge Machining (EDM) process in terms of tool wear rate (TWR), hole taper angle and material removal rate (MRR). In addition to a plain cylindrical shape, electrodes of different cross sections (slotted cylindrical, sharp-cornered triangular, round-cornered triangular, sharp-cornered square, round-cornered square, sharp-cornered hexagonal and round-cornered hexagonal) were designed as a means of inducing debris egress and then fabricated in graphite. EDM drilling trials using the rotating shaped electrodes were carried out on a Ti6Al4V workpiece. The results revealed that, although a low TWR and minimum hole taper angle were achieved using a plain cylindrical electrode, the usage of rotating shaped electrodes provided self-flushing of the dielectric fluid during the EDM process, which led to an improvement in MRR compared to that achieved with a plain cylindrical electrode. Besides, in general, the electrodes with rounded corners are associated with a lower TWR, a lower hole taper angle and a higher MRR when compared to the electrodes with sharp corners. Considering these results, it was concluded that different process attributes, i.e., TWR, hole taper angle and MRR, are all greatly affected by the electrode shape, and thus, the proper selection of the electrode shape is a precondition to attain a specific response from the EDM process.

Ultrasonic Vibration Assisted Electro-Discharge Machining (EDM)-An Overview.

Many of the industrial processes, including material removal operation for shape generation on the surface of material, exploit the assistance of ultrasonic vibrations. This trend of using ultrasonic vibration in order to improve the process performance is becoming more and more prominent recently. One of the significant applications of this ultrasonic vibration is in the industrial processes such as Electro-discharge machining (EDM), where ultrasonic vibration (UV) is inserted as a medium for enhancing the process performance. Mostly ultrasonic vibration is applied along with the EDM process to increase the efficiency of the process through debris cleansing from the sparking gap. There have been significant changes in ultrasonic assisted technology during the past years. Due to its inherent advantages, ultrasonic assistance infiltrated in different areas of EDM, such as wire cut EDM, micro EDM and die sinking EDM. This article presents an overview of ultrasonic vibration applications in electric discharge machining. This review provides information about modes of UV application, impacts on parameters of performance, optimization and process designing on difficult-to-cut materials. On the bases of available research works on ultrasonic vibration assisted EDM, current challenges and future research direction to improve the process capabilities are identified. Literature suggested improved material removal rate (MRR), increased surface roughness (SR) and tool wear ratio (TWR) due to the application of ultrasonic vibration assisted EDM. However, tool wear and surface roughness can be lessened with the addition of carbon nanofiber along with ultrasonic vibration. Moreover, the application of ultrasonic vibration to both tool and workpiece results in higher MRR compared to its application to single electrode.

'Application of MQL for Developing Sustainable EDM and Process Parameter Optimization using ANN and GRA Method'

This paper addresses the experimental-based optimisation of near dry EDM process on duplex stainless steel 2,205 grade material under minimum quantity lubrication (MQL) for improving the sustainability. Taguchi's L9 orthogonal array experimental design has been executed for varying input parameters like pulse-on time, pulse-off time, current and voltage. The machining performance is analysed by measuring the material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR). The obtained results are analysed by the artificial neural network (ANN) and grey relational analysis (GRA) for the multi-response optimisation. In multi-response optimisation, the optimum combination of parameters derived using GRA lead to the improvement of material removal rate at 6.1287 mm3/min and reduced electrode wear rate 0.0698 mm3/min at optimal parameters levels (TON = 450 μs, TOFF = 50 μs, current = 16 A, and voltage = 5 V). From the results, optimisation of MQL-based near dry EDM method proved some benefits in terms of improved sustainability.

Performance Study of Eco-friendly dielectric in EDM of AISI 2507 Super Duplex Steel using Taguchi -Fuzzy-TOPSIS Approach

In the present study, the application of Pongamia natural ester as a renewable green dielectric (GD) applied in the electric discharge machining (EDM) of AISI 2507 super duplex steel. This investigation aims to study the effect of Pongamia green dielectric in the EDM process. The major process variables such as pulse-on time (TON), pulse-off time (TOFF), peak current (IP), voltage (v) and inter-electrode gap (IEG) on performance measures like material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR). The Taguchi's orthogonal array (OA) L27 has been selected for this experimentation. The choice of optimal input parameter settings that are attained by multi-response optimisation of performance measures using Taguchi-fuzzy-TOPSIS technique is TON = 500 μs, TOFF = 30 μs, IP = 15 A, v = 40 V and IEG = 180 μm. The optimal settings have increased the productivity aspects by the four decision makers (DM) order priorities. The optimised results, shown the improvement in MRR with the minimised EWR and SR. The optimal settings of the process for improved machining responses were identified by Taguchi's response graph and analysis of variance (ANOVA). The recast layer and micrographs were examined utilising scanning electron microscopy (SEM).

Modelling and optimization of technological parameters in hot abrasive jet machining of alumina ceramic

The present work focuses on the experimental investigation of hot abrasive jet machining (HAJM) and precision drilling operation on flat surfaces of K-60 alumina ceramic material using different grades of silicon carbide abrasives. The machining AJM setup is designed based on fluidized bed mixing chamber along with pressurized powder feed chamber. The experiments are performed as per Box-Behnken design of experiments (BBDOEs) with four process parameters (pressure, stand of distance, abrasive temperature and grain size) for parametric optimization in order to control the two technological response characteristics (material removal rate, flaring diameter) of the precision holes on K-60 alumina. Analysis of variance (ANOVA), response surface methodology (RSM) and genetic algorithm (GA) are subsequently proposed for predictive modelling and process optimization. Result shows that application of hot abrasives in AJM process has excellent performance in terms of improved material removal rate, and minimum dimensional deviation of drilled hole. Multi-response optimization GA technique presented the optimal setting of machining variables in HAJM process at air pressure of 6.682 kgf/cm2, abrasive temperature of 60.6 °C, stand-off-distance of 7.1124 mm, abrasive grain size of 275.755 µm, with estimated maximal material removal rate of 0.005 gm/s and minimal flaring diameter of 6.382 mm. The methodology described here is expected to be highly beneficial to manufacturing industries.

Material Removal Rate and Tool Wear Rate on Machining of Inconel 718 using Electrical Discharge Machine

Electrical discharge machining is a manufacturing process with a large industrial implementation. The addition of powder particles in suspension in the dielectric modifies some process variables and creates hard and brittle materials with nano surface finish, high tolerance and accuracy to achieve a material removal rate increase. This paper presents a research work to study the performance improvement of material removal rate (MRR) and tool wear rate (TWR)on the nano particle mixed electrical discharge machining. Work piece used is Inconel 718 and tool materials used brass electrode. The electrolyte used is kerosene oil. Titanium carbide nano particle is having high mechanical and electrical properties specifically high electrical conductivity. The input parameters like current, pulse on-time and pulse off-time and outputs MRR and TWR. The experiment results analysis titanium carbide nano particle mixed dielectric fluid to achieve maximum MRR and minimize TWR.

Experimental studies on graphite powder-mixed electro-discharge machining of Inconel 718 super alloys: Comparison with conventional electro-discharge machining

Inconel 718 is a nickel-based super alloy widely applied in aerospace, automotive, and defense industries. Low thermal conductivity, extreme high temperature strength, strong work-hardening tendency make the alloy difficult-to-cut. In contrast to traditional machining, nonconventional route like electro-discharge machining is relatively more advantageous to machine this alloy. However, low thermal conductivity of Inconel 718 restricts electro-discharge machining from performing well. In order to improve the electro-discharge machining performance of Inconel 718, powder-mixed electro-discharge machining was reported in this paper. It was carried out by adding graphite powder to the dielectric media in consideration with varied peak discharge current. The morphology and topographical features of the machined surface including surface roughness, crack density, white layer thickness, metallurgical aspects (phase transformation, crystallite size, microstrain, and dislocation density), material migration, residual stress, microindentation hardness, etc. were studied and compared with that of the conventional electro-discharge machining. Additionally, effects of peak discharge current were discussed on influencing different performance measures of powder-mixed electro-discharge machining. Material removal efficiency and tool wear rate were also examined. Use of graphite powder-mixed electro-discharge machining was found to be better in performance for improved material removal rate, superior surface finish, reduced tool wear rate, and reduced intensity as well as severity of surface cracking. Lesser extent of carbon migration onto the machined surface as observed in powder-mixed electro-discharge machining in turn reduced the formation of hard carbide layers. As compared to the conventional electro-discharge machining, graphite powder-mixed electro-discharge machining exhibited relatively less microhardness and residual stress at the machined surface.

Magnetorheological fluid polishing using an electromagnet with straight pole-piece for improving material removal rate

Mechanical grinding techniques can cause residual stress, micro-cracks, and work hardening in workpieces. Processes employing magnetorheological (MR) fluid aim to reduce subsurface damage by avoiding the direct application of mechanical force. However, the material removal rate (MRR) achieved with processes such as MR fluid polishing is relatively low. In this study, operating conditions to improve MRR are analyzed using the design of experiments method. Through experiment, and using factorial analysis, it is concluded that MRR depends on magnetic field strength, depth of polishing, and polishing time. Based on these results, a re-designed electromagnet is proposed, analyzed, and tested.

Experimental Set Up to Improve Machining Performance of Silicon Dioxide (Quartz) in Magnetic Field Assisted TW-ECSM Process

In the present scenario, machining of the pioneering engineering materials such as various ceramics and composites which possess high hardness, brittleness, strength and electrically insulated becomes very difficult. This study focuses on the development of magnetic field assisted traveling wire electrochemical spark machining (MF-TWECSM) process set up and its utilization for the machining of electrically insulated materials. TW-ECSM process is a combination of the Wire-EDM and ECM processes. In this process, effects of the electrochemical reaction and electric spark are responsible for the material removal from the workpiece. Quartz found to be suitable as work material due its high hardness, good chemical stability and piezoelectric properties. Magnetic field has been applied during the machining for better circulation of the electrolyte during experimentation. Enhanced electrolyte circulation improves the efficiency of the process resulting in higher material removal rate (MRR) of the work material and reduction in the discharge current during experimentation. The improvement in MRR with magnetic field was found in the percentage range of 9% to 200% during experimentation. For the very first time, a brass wire with diameter 0.1 mm has been used during TW-ECSM process.

Combined machining of SiC/Al composites based on blasting erosion arc machining and CNC milling

In this study, a combined method is proposed for the machining of SiC/Al matrix composites to achieve high efficiency and better surface quality based on blasting erosion arc machining (BEAM) and computer numerical control (CNC) milling. The combined method consists of two stages. BEAM is adopted in the first stage to achieve a high machining efficiency. During this stage, the negative BEAM is used for improving material removal rate (MRR) while positive BEAM is adopted to reduce roughness of machined surface. In the second stage, CNC milling is utilized to achieve a fine surface. Firstly, in order to perform the combined processing, a special machine tool system is designed. Secondly, machining efficiency of the combined processing is discussed. It is disclosed that in the negative BEAM step, when peak current is 600 A, MRR of 20 vol.% SiC/Al and 50 vol.% SiC/Al composites can be as high as 10,200 and 7500 mm3/min separately. Thirdly, comparison experiments are designed and surface integrity (e.g., surface topography, surface roughness, heat affect zone, surface hardness, compositions) of each machining stage is analyzed. It is demonstrated that in the CNC milling stage, side effects of BEAM on the workpiece (e.g., rough surface, thick heat affect zone) can be eliminated effectively. The roughness of the machined surface can be lower than Ra 0.5 μm; heat affect zone (HAZ) and debris almost cannot be observed. Finally, a SiC/Al workpiece is machined to demonstrate the advantages of the combined machining of SiC/Al matrix composites.

Evaluation and improvement of material removal rate with good surface quality in TC4 blisk blade polishing process

Evaluation and improvement of material removal rate with good surface quality in TC4 blisk blade polishing process

Study of Machining of Inconel 825 Super Alloy Using Powder Mixed EDM Process

Powder mixed electrical Discharge Machining (PMEDM) plays vital role in machining process of some very difficult to machine materials. Inconel 825 are highly demanding materials for today’s industries due to their unique properties. Properties like high creep resistance under high stress condition, high resistant to corrosion, good machinability, ductility, weldibility, low value of thermal expansion makes it durable for high speed aeroplanes and supersonic jets. In present work Inconel 825 (nickel alloy) which is widely used in aerospace industries, power plants, nuclear power plants, petro chemical, chemical rockets has been used as work piece and machined with using powder mixed electrical discharge machining process (PMEDM). Peak current (IP), gap voltage (GV), powder concentration (PC) and pulse on time (TON) are opted as input experimental parameters. Whereas, surface roughness (SR) and material removal rate (MRR) are considered as output response parameters. Tool used during experiment is tungsten carbide. Tungsten carbide is hard materials in which wear is minimum. It could be concluded from the experiment that there is significant improvement in MRR as well as SR. Tool wear is negligible. Further, surface machined by PMEDM is compared with conventional EDM and analysed using field emission electron microscopy (FESEM) and RSM (response surface methodology). Images obtained by FESEM also confirm improvement in surface integrity. Moreover, less micro-crack, micro-holes and shallower craters were observed on the surface generated by PMEDM as compare to conventional EDM