scholarly journals Analysis, predictive modelling and multi-response optimization in electrical discharge machining of Al-22%SiC metal matrix composite for minimization of surface roughness and hole overcut

2020 ◽  
Vol 7 ◽  
pp. 20 ◽  
Author(s):  
Subhashree Naik ◽  
Sudhansu Ranjan Das ◽  
Debabrata Dhupal

Due to the widespread engineering applications of metal matrix composites especially in automotive, aerospace, military, and electricity industries; the achievement of desired shape and contour of the machined end product with intricate geometry and dimensions that are very challenging task. This experimental investigation deals with electrical discharge machining of newly engineered metal matrix composite of aluminum reinforced with 22 wt.% of silicon carbide particles (Al-22%SiC MMC) using a brass electrode to analyze the machined part quality concerning surface roughness and overcut. Forty-six sets of experimental trials are conducted by considering five machining parameters (discharge current, gap voltage, pulse-on-time, pulse-off-time and flushing pressure) based on Box-Behnken's design of experiments (BBDOEs). This article demonstrates the methodology for predictive modeling and multi-response optimization of machining accuracy and surface quality to enhance the hole quality in Al-SiC based MMC, employing response surface methodology (RSM) and desirability function approach (DFA). Finally, a novel approach has been proposed for economic analysis which estimated the total machining cost per part of rupees 211.08 during EDM of Al-SiC MMC under optimum machining conditions. Thereafter, under the influence of discharge current several observations are performed on machined surface morphology and hole characteristics by scanning electron microscope to establish the process. The result shows that discharge current has the significant contribution (38.16% for Ra, 37.12% in case of OC) in degradation of surface finish as well as the dimensional deviation of hole diameter, especially overcut. The machining data generated for the Al-SiC MMC will be useful for the industry.

Volume 3 ◽  
2004 ◽  
Author(s):  
Kuen Ming Shu ◽  
Hung Rung Shih ◽  
Wen Feng Lin ◽  
G. C. Tu

Electrical discharge machining (EDM) has been shown to be a versatile method for machining difficult-to-work materials including heated-treated steels, tungsten carbides and various conductive ceramics. However, low machining efficiency is one of the main EDM disadvantages. The topic of how to reduce machining time and maintains reasonable accuracy has always been of research interest. The main object of the present work was to develop an electrical discharge machining and grinding (EDMG) methodology to remove the re-solidified layer through the grinding induced by a metal matrix composite electrode prior to the re-solidified layer solidification. A metal matrix composite (Cu/SiCp) electrode, with an electroless pretreatment of Cu coating on SiCp to enhance bonding status between Cu and SiCp, with a rotating device was made and employed to study the EDMG technology. Machinabilities of mold material, HPM50 mold steel and P20 WC/Co, were investigated by the combined technologies of EDMG. The machined surfaces of these materials were examined by scanning electron microscopy (SEM) and their surface roughness measured by a profile meter. From the experimental results, it was found that higher material removal rate and lower surface roughness can be achieved when suitable electrode rotating speed, SiCp size and working current are chosen. In addition, the surface roughness of both materials could be improved as compared with that following the EDM process.


Micromachines ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 72 ◽  
Author(s):  
Rafał Świercz ◽  
Dorota Oniszczuk-Świercz ◽  
Tomasz Chmielewski

Electrical discharge machining (EDM) is a modern technology that is widely used in the production of difficult to cut conductive materials. The basic problem of EDM is the stochastic nature of electrical discharges. The optimal selection of machining parameters to achieve micron surface roughness and the recast layer with the maximal possible value of the material removal rate (MRR) is quite challenging. In this paper, we performed an analytical and experimental investigation of the influence of the EDM parameters: Surface integrity and MRR. Response surface methodology (RSM) was used to build empirical models on the influence of the discharge current I, pulse time ton, and the time interval toff, on the surface roughness (Sa), the thickness of the white layer (WL), and the MRR, during the machining of tool steel 55NiCrMoV7. The surface and subsurface integrity were evaluated using an optical microscope and a scanning profilometer. Analysis of variance (ANOVA) was used to establish the statistical significance parameters. The calculated contribution indicated that the discharge current had the most influence (over the 50%) on the Sa, WL, and MRR, followed by the discharge time. The multi-response optimization was carried out using the desirability function for the three cases of EDM: Finishing, semi-finishing, and roughing. The confirmation test showed that maximal errors between the predicted and the obtained values did not exceed 6%.


2014 ◽  
Vol 592-594 ◽  
pp. 405-409
Author(s):  
Arumugam Mahamani ◽  
N. Sakthivelon ◽  
Sai Kumar Jetti ◽  
M. Vijay Sekar Reddy ◽  
P. Vamsi Krishna Naidu ◽  
...  

In-situ aluminum matrix composites have good bonding strength and homogeneous distribution of particles, which offer improved mechanical property and wear resistance. Electrical discharge machining is considered as a suitable process for making complicated shape of difficult to machine materials. In this experimental work AA6061-6% TiB2/ZrB2in-situ metal matrix composite was fabricated using flex assisted synthesis. This experimental investigation is focused to study the influence of electrical discharge machining process parameter on surface roughness in machining of the AA6061-6% TiB2/ZrB2composite. Taguchi method and L9orthogonal lay out are applied to conduct the experimental work. Analysis of variance was performed to evaluate the percentage of contribution of each parameter. The analysis of the result indicates that discharge current has strongest influence on the surface roughness. This experimental study helps to select the optimal machining parameter to achieve good surface finish.


Author(s):  
TS Senthilkumar ◽  
R Muralikannan ◽  
T Ramkumar ◽  
S Senthil Kumar

A substantially developed machining process, namely wire electrical discharge machining (WEDM), is used to machine complex shapes with high accuracy. This existent work investigates the optimization of the process parameters of wire electrical discharge machining, such as pulse on time ( Ton), peak current ( I), and gap voltage ( V), to analyze the output performance, such as kerf width and surface roughness, of AA 4032–TiC metal matrix composite using response surface methodology. The metal matrix composite was developed by handling the stir casting system. Response surface methodology is implemented through the Box–Behnken design to reduce experiments and design a mathematical model for the responses. The Box–Behnken design was conducted at a confident level of 99.5%, and a mathematical model was established for the responses, especially kerf width and surface roughness. Analysis of variance table was demarcated to check the cogency of the established model and determine the significant process. Surface roughness attains a maximum value at a high peak current value because high thermal energy was released, leading to poor surface finish. A validation test was directed between the predicted value and the actual value; however, the deviation is insignificant. Moreover, a confirmation test was handled for predicted and experimental values, and a minimal error was 2.3% and 2.12% for kerf width and surface roughness, respectively. Furthermore, the size of the crater, globules, microvoids, and microcracks were increased by amplifying the pulse on time.


2014 ◽  
Vol 3 (2) ◽  
pp. 212
Author(s):  
M. Durairaj ◽  
A.K.S. Ansari ◽  
M. H. Gauthamkumar

Wire Electrical Discharge Machining is a manufacturing process whereby a desired shape is obtained using electrical discharges (or) by repetitive spark cycle. Precision and intricate machining are the strengths. Machining parameters tables provided by the machine tool manufacturers often do not meet the operator requirements. Selection of optimum machining and machining parameters combinations is needed for obtaining higher cutting efficiency and accuracy. In this present study, machining is done using Wire-Cut EDM and optimization of surface roughness is done using Taguchis design of experiments. Experimentation was planned as per Taguchis L16 orthogonal array. Each experiment has been performed under different cutting conditions of gap voltage, pulse ON time, and pulse OFF time and Wire feed. Dielectric fluid pressure, wire speed, wire tension, resistance and cutting length are taken as fixed parameters. Inconel 800 was selected as a work material to conduct the experiments. From experimental results, the surface roughness was determined for each machining performance criteria. Signal to noise ratio was applied to measure the performance characteristics deviating from the actual value. Finally, experimental confirmation was carried out to identify the effectiveness of this proposed method. Keywords: Optimization; Taguchis L-16 Orthogonal Array; Surface Roughness; S/N Ratio.


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