Multi-response optimization and modeling of trim cut WEDM operation of commercially pure titanium (CPTi) considering multiple user's preferences

In this research work, development of a multi response optimization technique has been undertaken, using traditional utility method in conjunction with the weight assignment concept (for multiple customer's priorities) in trim cut wire electrical discharge machining (WEDM). Pure titanium has been selected as work material for experimentation. The effect of key process parameters such a wire type (zinc coated and uncoated brass wire), pulse on time (TON), pulse off time (TOFF), peak current (IP), wire feed (WF), servo voltage (SV) and wire offset (WOFF) were investigated on material removal rate (MRR), surface roughness and wire weight consumption (eroded weight of wire after machining) in finish cut WEDM operation. Two different types of wire electrodes were taken for experimental research (uncoated, zinc coated). Further, the variation of the MRR was modeled semi-empirically through dimensional analysis. The developed model is mechanistic, as it can be used by the machinists to predict the MRR over a wide range of input parameters. The optimization of multiple responses has been done for satisfying the priorities of multiple users, in contrast to the traditional multi-response techniques where the optimized process setting is realized without giving any attention to the priorities of different users

Process Capability Analysis and Optimization in WEDM of Commercially Pure Titanium

AbstractIn this research, input parameters such as pulse on time (TON), pulse off time (TOFF), peak current (IP), wire feed (WF), wire tension (WT), and servo voltage (SV) has been selected for process capability investigation in WEDM process. The process capability index was evaluated for machining characteristics such as machined work-piece dimension (MWD) and surface roughness (SR). Taguchi's approach to experiment design and analysis was utilized to study the influence of machining parameters on the process capability index. Single response optimization was performed for both machining characteristics to find out the parametric setting which could optimize WEDM process capability. Surface integrity aspects such as microstructure analysis (including, debris, cracks, and crater size etc.) of the selected machined titanium samples have also been investigated

Parametric optimization and modelling of rough cut WEDM operation of pure titanium using grey-fuzzy logic and dimensional analysis

In this study, effects of input parameters such as pulse on time (TON), pulse off time (TOFF), peak current (IP), wire feed (WF), wire tension (WT) and servo voltage (SV) on machining characteristics such as material removal rate (MRR), surface roughness (SR) and wire weight consumption (WWC) were investigated in wire electric discharge machining (WEDM) process using commercially pure titanium as work material. The consumption of wire and its correlation with wire wear was also investigated. The responses were optimized simultaneously using grey-fuzzy logic approach. Surface integrity aspects such as microstructure analysis (including recast layer thickness, debris and cracks, crater size and shape, etc.) of the selected machined titanium samples have also been investigated to evaluate the suitability of WEDM for machining titanium. The material transfer mechanism between the zinc-coated wire electrode and the work surface has been studied using energy dispersive X-ray analysis. A mechanistic model has also been developed and validated for prediction of the response parameter (MRR) over a wide range of input variables

Laser processing of Ti composite coatings reinforced with hydroxyapatite and bioglass

Composite coatings of titanium reinforced separately with hydroxyapatite (HAp) and bioglass (BG) were deposited on titanium substrate using Laser Engineered Net Shaping (LENS (TM)). The microstructure, phase constituents, in vitro electrochemical, tribological and biological properties of these composite coatings deposited using different laser powers was studied. The composite coatings showed several reaction products such as Ca2P2O2, CaTiO3, Na2Ca2Si3O9 due to high temperature interaction of HAp and BG with Ti. The average top surface hardness of the Ti substrate was 148 +/- 5 HV and that of the composite coatings was between 720 and 740 HV. As a result, the composite coatings exhibited significant increase in the in vitro wear resistance. The incorporation of HAp and BG in Ti increased the corrosion current, possibly due to the presence of residual stresses, but shifted the corrosion potential towards noble direction due bioactive reinforcements. In vitro proliferation of mouse embryonic fibroblast cells (NIH3T3) was found to be more on composite coatings than on titanium substrate demonstrating their superior cell-materials interactions

Purtscher-like retinopathy: A rare ocular finding in nephrotic syndrome

In this report, we present a case of Purtscher-like retinopathy in a 12-year-old male child with nephrotic syndrome. He was a known case of steroid-dependent nephrotic syndrome, frequent relapser with spontaneous bacterial peritonitis, who presented with complaints of difficulty in vision in both eyes. The fundus examination showed multiple cotton-wool spots and Purtscher fleckens centered around the optic nerve head with superficial retinal hemorrhages in both eyes. Fluorescein angiography confirmed the diagnosis of Purtscher-like retinopathy

Quantification of water footprint of National Capital Territory (NCT) of Delhi

106-114Over, exploitation of fresh,water caused by the increasing population and urbanization over the past few decades has resulted in water scarcity in National Capital Territory (NCT) of Delhi. Water footprint (WF) is a useful tool to better understand the linkages between humanity's activities and their growing pressure on the freshwater resources. It indicates the amount of water required to produce all the goods and services by the individual or community, or geographic area directly and indirectly (virtual water). It is measured in terms of water volumes consumed (evaporated) and/or polluted per unit of time. Many studies have been carried out pertaining to the water requirement of NCT of Delhi. The present study is focused on the assessment of the WF of NCT of Delhi. The total WF of NCT of Delhi for the year 2010 has been assessed as 15,926 MCM per annum. Out of this 6530, 780 and 865 MCM per annum has been contributed from domestic, agriculture and industrial sector, respectively and rest (7751 MCM per annum) is as virtual water import. Certain assumptions were made due to non-availability of some of the data. With the availability of more data, the assessment can be improved. Quantification of WF of NCT of Delhi indicates that domestic sector is the major water consumer. Sector wise results can facilitate authorities to develop improved management policies, action plans and strategies for better management of fresh water resources

Recycled Ti-17 Based Composite Design; Optimization Process Parameters in Wire Cut Electrical Discharge Machining (WEDM)

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