STUDY OF MATERIAL REMOVAL RATE OF DIFFERENT TOOL MATERIALS DURING EDM OF H 11 STEEL AT REVERSE POLARITY
Electric Discharge Machining (EDM) is a non-traditional machining process that involved a momentary spark discharges through the fluid due to the potential difference between the electrode and the workpiece. In EDM, improper choose of the electrode material may cause poor machining rate (or) performance. This is due to material removal rate characteristics. Less material removal rate (MRR) needs more time for machining process and become waste which is not good for production. Hence in this study, the effect of input parameters of EDM process ie. electrode type, peak current, gap voltage, and duty cycle on material removal rate of H11 steel are experimentally investigated. A L18 Taguchi’s standard orthogonal array is used for experimental design. Conventional Copper (Cu) and powder metallurgy (PM) copper tungsten (CuW) are used as tool materials. It was found that conventional copper tool electrode gives maximum MRR and best parametric setting for maximum MRR was found at, Cu (99% Cu) tool electrode, 9 ampere current, 50 volts gap voltage and 0.92 duty cycle. ie. A1B2C2D3.
ANALYSIS OF TOOL MATERIAL ON METAL REMOVAL RATE IN ELECTRICAL DISCHARGE MACHINING
H11 tool steel is an exceptional class of alloy steel, also known as chromium tool steel. It found applications in forging and extrusion dies, helicopter rotor blades etc. Electrical discharge machining (EDM) is one of the alternative processes to shape this material. This study exhibits the effect of discharge current (Id) and gap voltage (Vg) on metal removal rate (MRR) during EDM of H11 tool steel by taking three different tool electrode materials. Experiments have been performed by varying Id in four steps (4 A, 8A, 12 A, 16 A) and Vg in (25 V, 30 V, 35 V, 40 V) while keeping the values of other variable fixed. On the basis of experimental findings, it is concluded that tool properties of the electrode play a crucial role in machining characteristics of EDM process. The results show that graphite electrode offers the higher MRR followed by aluminium and copper electrode in EDM of H11 tool steel.
Mucoadhesive Nanoparticles for Drug Delivery to the Anterior Eye
While the use of topical drops for the delivery of drugs to the anterior of the eye is well accepted, it is far from efficient with as little as 5% of the drug instilled on the eye actually reaching the target tissue. The ability to prolong the residence time on the eye is desirable. Based on the acceptability of 2-hydroxyethyl methacrylate based polymers in contact lens applications, the current work focuses on the development of a poly(2-hydroxyethyl methacrylate (HEMA)) nanoparticle system. The particles were modified to allow for degradation and to permit mucoadhesion. Size and morphological analysis of the final polymer products showed that nano-sized, spherical particles were produced. FTIR spectra demonstrated that the nanoparticles comprised poly(HEMA) and that 3-(acrylamido)phenylboronic acid (3AAPBA), as a mucoadhesive, was successfully incorporated. Degradation of nanoparticles containing N,N′-bis(acryloyl)cystamine (BAC) after incubation with DL-dithiothreitol (DTT) was confirmed by a decrease in turbidity and through transmission electron microscopy (TEM). Nanoparticle mucoadhesion was shown through an in-vitro zeta potential analysis.