Optimization of Machining Parameters in EDM Process Using Cast and Sintered Copper Electrodes

AbstractIn this research work two different materials have been used as work pieces. These EN8 and D3 steel materials have been machined in an Electrical discharge machine which has wide application in Industry fields. The important process parameters that have been selected are peak current, pulse on time, die electric pressure and tool diameter. The outputs responses are material removal rate (MRR), tool wear rate (TWR) and surface roughness (SR). The Cast Copper and Sintered Powder Metallurgy Copper (P/M Copper) have been considered as tool electrodes to machine the fore said work pieces. Response surface methodology(RSM) has been used to analyze the parameters and analysis of variance (ANOVA) has been applied to identify the significant process parameters. The influences of interaction of parameters have also been studied. Scanned electron microscope(SEM) images have been taken after machining on the work pieces for both electrodes to study the structure property correlation. The input parameters were optimized in order to obtain maximum MRR, minimum TWR and minimum SR

Nonlocal symmetries of Riccati and Abel chains and their similarity reductions

We study nonlocal symmetries and their similarity reductions of Riccati and Abel chains. Our results show that all the equations in Riccati chain share the same form of nonlocal symmetry. The similarity reduced $N^{th}$ order ordinary differential equation (ODE), $N=2, 3,4,...$, in this chain yields $(N-1)^{th}$ order ODE in the same chain. All the equations in the Abel chain also share the same form of nonlocal symmetry (which is different from the one that exist in Riccati chain) but the similarity reduced $N^{th}$ order ODE, $N=2, 3,4,$, in the Abel chain always ends at the $(N-1)^{th}$ order ODE in the Riccati chain. We describe the method of finding general solution of all the equations that appear in these chains from the nonlocal symmetry.Comment: Accepted for publication in J. Math. Phy

A unification in the theory of linearization of second order nonlinear ordinary differential equations

In this letter, we introduce a new generalized linearizing transformation (GLT) for second order nonlinear ordinary differential equations (SNODEs). The well known invertible point (IPT) and non-point transformations (NPT) can be derived as sub-cases of the GLT. A wider class of nonlinear ODEs that cannot be linearized through NPT and IPT can be linearized by this GLT. We also illustrate how to construct GLTs and to identify the form of the linearizable equations and propose a procedure to derive the general solution from this GLT for the SNODEs. We demonstrate the theory with two examples which are of contemporary interest.Comment: 8 page

<span style="font-size:11.0pt;font-family: "Times New Roman","serif";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Synthesis and Characterisation of Al 7075 reinforced with SiC and B₄C nano particles fabricated by ultrasonic cavitation method</span>

281-285<span style="font-size:11.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-bidi-font-family:="" mangal;mso-ansi-language:en-gb;mso-fareast-language:en-us;mso-bidi-language:="" hi"="" lang="EN-GB">The application of ultrasonic effects to disperse nano sized particles in molten metal has been studied. Based on this technique, nano-sized SiC and B4C particles reinforced with AL7075 aluminium nanocomposites were fabricated. XRD analysis reveals that uniform structure of nano composites was formed in the Al alloy. The microstructure of the nanocomposites was investigated by high resolution scanning electron microscope (SEM). Experimental results show a nearly uniform distribution and good dispersion of the SiC and B4C nanoparticles within the aluminium metal matrix, although some small clusters were found in the matrix. The mechanical properties like tensile strength and micro hardness of nanocomposites have been improved significantly compared to that of pure alloy. The interaction between SiC and B4C nanoparticles with aluminium matrix was investigated.</span

Constitutive equation and microstructure evaluation of an extruded aluminum alloy

The flow-stress behavior of an extruded aluminum alloy has been studied by conducting a set of warm and hot compression tests. The compression tests were carried out in the temperature range of 373 K–773 K and strain rates of 0.001, 0.01 and 0.1 s−1, up to a strain of 0.5. Based on the results obtained from these tests, a mathematical model was obtained to predict flow stress for a given strain. The effect of temperature and strain rate on deformation behavior was ascertained by determining the Zener–Hollomon parameter. The influence of strain has been incorporated by employing an Arrhenius-type constitutive equation, considering the related material constants as functions of strain. The comparison of results indicated good agreement between the predicted and measured flow-stress values in the relevant temperature range. The correlation coefficient and average absolute relative error of the model were found to be 0.9965 and 4.26% respectively confirming good accuracy

Mathematical modeling of process parameters on hard turning ofAISI 316 SS by WC insert

592-596This paper presents a newly developed mathematical modeling for process parameters on hard turning of AISI 316stainless steel by tungsten carbide inserts (WC). Regression analysis and ANOVA theory was used to predict surface roughness(Ra) and tool wear (VB). WC tool inserts performed machining of AISI 316 SS to study main and interaction effects of processparameters [cutting speed (Vs), feed rate (fs) and depth of cut (ap)]. Adequacies of developed model were verified by calculationof correlation coefficient (r). These models can be effectively used to predict Ra of work piece and VB of WC insert

Statistical optimization of EDM parameters on machining of aluminium Hybrid Metal Matrix composite by applying Taguchi based Grey analysis

358-365Hybrid metal matrix composite is a recent kind of material which are not only focused on the improvement of mechanical properties, but also on machinability for difficult-to-machine shapes using EDM. Experiments were conducted by choosing the typical process parameters such as pulse current, gap voltage, pulse on time and pulse off time. The Taguchi based grey relational analysis was adopted to obtain grey relational grade for EDM process with multiple characteristics namely material removal rate (MRR), electrode wear ratio (EWR) and surface roughness (SR). The significance of process parameters was obtained by analysis of variance based on grey relational grade, which showed pulse current and pulse on time to be the most significant parameters