Optimization of Machining Condition in WEDM for Titanium Grade 6 Using MOORA Coupled with PCA — A Multivariate Hybrid Approach

2017 ◽  
Vol 16 (02) ◽  
pp. 81-99 ◽  
Author(s):  
Himadri Majumder ◽  
Kalipada Maity

This paper represents a multivariate hybrid approach, combining Multi-Objective Optimization on the basis of Ratio Analysis (MOORA) and Principal Component Analysis (PCA) to optimize different correlated responses during Wire Electrical Discharge Machining (WEDM) process of titanium grade 6. The response parameters selected are the average cutting speed, average Kerf width and average surface roughness (Ra). All of them have been studied in terms of pulse-ON time, pulse-OFF time, wire feed and wire tension. As indicated by Taguchi’s signal-to-noise ratio, the optimum process parameters were achieved for the desired average cutting speed, average Kerf width and average surface roughness, respectively. At last, the optimum combination of process parameters was validated by affirmation test which gave considerably improved various quality characteristics. Confirmation test outcome revealed that multivariate hybrid approach MOORA coupled with PCA was a competent strategy to decide available cutting parameters for a desired response quality for WEDM of titanium grade 6.

2020 ◽  
Vol 14 ◽  
Author(s):  
MS Shekhawat ◽  
Harlal Singh Mali ◽  
APS Rathore

Aims & Objective: Producing thin walled rotationally symmetrical parts of difficult-to-machine materials by electrical discharge machining is an evolving field of research. Poor heat transmissivity, high hot strength and in-process deflection of thin walled Inconel 600 parts puts great challenge for its processing by conventional machining methods. Methods: In this study a novel hybrid process called centreless electric discharge grinding(CEDG) is employed for machining of Inconel 600 tubes using rotating disc wheel electrode to improve process parameters. This paper details about the experimental findings of the influence of four process parameters viz. pulse on time, peak current, gap voltage, and duty cycle on the responses viz. average material removal rate (MRR) and average surface roughness(Ra). Response surface method’s (RSM) central composite design was implemented to determine the effects of parameters on responses. Analysis of variance (ANOVA) techniques were employed to establish the adequacy of the mathematical models and to analyse the significance of regression coefficients. RSM’s desirability approach was used to solve the multi-response optimization. Results: It was clearly noticed that the peak current and gap voltage were the most influential parameters to affect the MRR and surface roughness. Maximum average MRR of 473 mg per min. was achieved at pulse on time 60µs, peak current 25 amps, gap voltage 40 V, at duty cycle of 8 while minimum average surface roughness of 8.4 µm Ra was obtained at pulse on time 40µs, peak current 15 amps, gap voltage 40 V, and duty cycle 6. Conclusion: Confirmation run was conducted by adjusting the variables at optimal level within the selected range. It was concluded that optimum level of variables can be determined for optimized responses prior to conduct of experiment.


2018 ◽  
Vol 7 (2.8) ◽  
pp. 10
Author(s):  
A VS Ram Prasad ◽  
Koona Ramji ◽  
B Raghu Kumar

Machining of Titanium alloys is difficult due to their chemical and physical properties namely excellent strength, chemical reactivity and low thermal conductivity. Traditional machining of such materials leads to formation of continuous chips and tool bits are subjected to chatter which leads to formation of poor surface on machined surface. In this study, Wire-EDM one of the most popular unconventional machining process which was used to machine such difficult-to-cut materials. Effect of Wire-EDM process parameters namely peak current, pulse-on- time, pulse-off-time, servo voltage on MRRand SR was investigated by Taguchi method. 0.25 mm brass wire was used in this process as electrode material. A surface roughness tester (Surftest 301) was used to measure surface roughness value of the machined work surface. A multi-response optimization technique was then utilized to optimize Wire-EDM process parameters for achieving maximum MRR and minimum SR simultaneously.


2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Ekhaesomi A Agbonoga ◽  
Oyewole Adedipe ◽  
Uzoma G Okoro ◽  
Fidelis J Usman ◽  
Kafayat T Obanimomo ◽  
...  

This study investigated the effects of process parameters of plasma arc cutting (PAC) of low carbon steel material using analysis of variance. Three process parameters, cutting speed, cutting current and gas pressure were considered and experiments were conducted based on response surface methodology (RSM) via the box-Behnken approach. Process responses viz. surface roughness (Ra) and kerf width of cut surface were measured for each experimental run. Analysis of Variance (ANOVA) was performed to get the contribution of process parameters on responses. Cutting current has the most significant effect of 33.43% on the surface roughness and gas pressure has the most significant effect on  kerf width of  41.99% . For minimum surface roughness and minimum kerf width, process parameters were optimized using the RSM. Keywords: Cutting speed, cutting current, gas pressure,   surface roughness, kerf width


Author(s):  
Prathik Jain Sudhir ◽  
Ravindra Holalu Venkatadas ◽  
Ugrasen Gonchikar

Abstract Wire Electrical Discharge Machining (WEDM) provides an effective solution for machining hard materials with intricate shapes. WEDM is a specialized thermal machining process is capable to accurately machining parts of hard materials with complex shapes. However, selection of process parameters for obtaining higher machining efficiency or accuracy in wire EDM is still not fully solved, even with the most up-to-date CNC WED machine. The study presents the machining of Titanium grade 2 material using L’16 Orthogonal Array (OA). The process parameters considered for the present work are pulse on time, pulse off time, current, bed speed, voltage and flush rate. Among these process parameters voltage and flush rate were kept constant and the other four parameters were varied for the machining. Molybdenum wire of 0.18mm is used as the electrode material. Titanium is used in engine applications such as rotors, compressor blades, hydraulic system components and nacelles. Its application can also be found in critical jet engine rotating and airframes components in aircraft industries. Firstly optimization of the process parameters was done to know the effect of most influencing parameters on machining characteristics viz., Surface Roughness (SR) and Electrode Wear (EW). Then the simpler functional relationship plots were established between the parameters to know the possible information about the SR and EW. This simpler method of analysis does not provide the information on the status of the material and electrode. Hence more sophisticated method of analysis was used viz., Artificial Neural Network (ANN) for the estimation of the experimental values. SR and EW parameters prediction was carried out successfully for 50%, 60% and 70% of the training set for titanium material using ANN. Among the selected percentage data, at 70% training set showed remarkable similarities with the measured value then at 50% and 60%.


2020 ◽  
Vol 17 (3) ◽  
pp. 389-397
Author(s):  
Harvinder Singh ◽  
Vinod Kumar ◽  
Jatinder Kapoor

Purpose This study aims to investigate the influence of process parameters of wire electrical discharge machining (WEDM) of Nimonic75. Nimonic75 is a Nickel-based alloy mostly used in the aerospace industry for its strength at high temperature. Design/methodology/approach One factor at a time (OFAT) approach has been used to perform the experiments. Pulse on time, pulse off time, peak current and servo voltage were chosen as input process parameters. Cutting speed, material removal rate and surface roughness (Ra) were selected as output performance characteristics. Findings Through experimental work, the effect of process parameters on the response characteristics has been found. Results identified the most important parameters to maximize the cutting speed and material removal rate and minimize Ra. Originality/value Very limited research work has been done on WEDM of Nickel-based alloy Nimonic75. Therefore, the aim of this paper to conduct preliminary experimentation for identifying the parameters, which influence the response characteristics such as material removal rate, cutting speed, Ra, etc. during WEDM of Nickel-based alloy (Nimonic75) using OFAT approach and found the machinability of Nimonic75 for further exhaustive experimentation work.


2019 ◽  
Vol 11 (7) ◽  
pp. 168781401983631 ◽  
Author(s):  
István Gábor Gyurika ◽  
Tibor Szalay

Automated stone manufacturing has undergone considerable development in recent years. Thanks to international research dealing with the cutting, sawing and grinding of different natural stones, processing time shortens and tool-life lengthens. However, the process of stone milling has not been extensively examined yet, primarily because of the novelty of this technology. The aim of the research described in this article is to examine how variable cutting speed affects the quality of workpiece edges while milling granite materials. For the research, sample surfaces were formed on five granite slabs with different average grain sizes using five cutting speed values. Afterwards, changes in the average surface roughness and average edge chipping rate were examined. From the research results, it can be concluded that, due to an increase in cutting speed, the average edge chipping rate will decrease until reaching a borderline speed. In the case of a higher cutting speed, the referent tendency cannot be ascertained. A statistical analysis conducted in the scope of this research showed that if a variable cutting speed is applied, then changes in the quality of the sample surface edge can be inferred from the development trends of average surface roughness.


2018 ◽  
Vol 249 ◽  
pp. 02003 ◽  
Author(s):  
Bhupinder Singh ◽  
Joy Prakash Misra

Cutting speed (CS) is a key performance measure to achieve optimal utilization of the WEDM process. However, input process parameters of WEDM and combination of wire and workpiece material greatly hamper CS and hence productivity and machining efficiency. Therefore, it is essential to pick the right combination of parameters and wire and workpiece material to obtain better CS. In this paper, four process parameters: Pulse-on time, Pulse-off time, Spark-gap voltage, and Peak current were chosen to develop an empirical model for CS during WEDM of Hastelloy C22 to provide a guideline to the potential users of the technique. This paper describes the response surface methodology (RSM) based mathematical modeling for average cutting speed. Furthermore, analysis of variance (ANOVA) was applied to find out significant process parameters and it was depicted that pulse on time and peak current were the major parameters affecting CS.


2014 ◽  
Vol 592-594 ◽  
pp. 416-420 ◽  
Author(s):  
Singaravelu D. Lenin ◽  
A. Uthirapathi ◽  
Ramana Reddy P.S. Venkata ◽  
Muthukannan Durai Selvam

The present paper describes the influence of pulse-on-time on performance features such as Metal Removal Rate (MRR), Kerf width, Surface Roughness (SR) on cutting Titanium alloy (Ti-6Al-4V) in wire electrical discharge machining (WEDM) using zinc coated brass wire. The deionised water is used as dielectric fluid. The process parameters such as wire tension, wire speed, flushing pressure, discharge current, sparking voltage and pulse off time have kept constant at appropriate values throughout the experiment and the pulse on time is varied at nine different intervals. It was found that pulse-on-time is the most significant factor which greatly influences MRR, kerf width, and SR. It was also observed that taper at the end of cutting zone which is unavoidable occurrence for the machined part. This is due to the erosion of wire material. The surface roughness increases with increase in pulse on time also with higher rate of MRR.


2014 ◽  
Vol 592-594 ◽  
pp. 831-835 ◽  
Author(s):  
Vikram Singh ◽  
Sharad Kumar Pradhan

The objective of the present work is to investigate the effects of various WEDM process parameters like pulse on time, pulse off time, corner servo, flushing pressure, wire feed rate, wire tension, spark gap voltage and servo feed on the material removal rate (MRR) & Surface Roughness (SR) and to obtain the optimal settings of machining parameters at which the material removal rate (MRR) is maximum and the Surface Roughness (SR) is minimum in a range. In the present investigation, Inconel 825 specimen is machined by using brass wire as electrode and the response surface methodology (RSM) is for modeling a second-order response surface to estimate the optimum machining condition to produce the best possible response within the experimental constraints.


2015 ◽  
Vol 766-767 ◽  
pp. 902-907
Author(s):  
Bibin K. Tharian ◽  
B. Kuriachen ◽  
Josephkunju Paul ◽  
Paul V. Elson

Wire electrical discharge machining is one of the important non-traditional machining processes for machining difficult to machine materials. It involves the removal of material by the discrete electric discharges produced between the inter electrode gap of continuously moving wire electrode and the work piece. The ability to produce intricate profiles on materials irrespective of the mechanical properties made this process to be widely used in industries. The present study investigates the relationship of various process parameters in WEDM of AISI 202 stainless steel with brass electrode.The experiments were planned according to Taguchi’s L18 orthogonal array and experimental models were developed. The important process parameters identified for the present study were pulse on time, peak current, pulse off time, wire feed, wire tension, dielectric flushing pressure, servo feed and gap voltage. The surface roughness of the machined surface was measured as the process performance measure. Analysis of variance test has also been carried out to check the adequacy of the developed models and to identify the level of significance of each process parameters. In addition to the developed models, ABC optimization has been performed to identify the optimum parameter combination for minimum surface roughness and the obtained optimal process parameters are peak current 11 A, pulse on time 100 μs, pulse off time 49 μs, wire feed 4 m/min, wire tension 10 N, flushing pressure 12 kg/cm2, servo feed 2100 mm/min and set gap voltage 30 V. Finally the results were verified with the experimental results and found that they are in good agreement.


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