J. Ramkumar

Nano-Cutting Fluid for Enhancement of Metal Cutting Performance

Nano-cutting fluids are the mixtures of conventional cutting fluid and nanoparticles. Addition of the nanoparticles can alter wettability, lubricating properties, and convective heat transfer coefficient (cooling properties) of nano-cutting fluids. In the present work, nano-cutting fluid is made by adding 1% Al2O3 nanoparticles to conventional cutting fluid. The wettability characteristic of this nano-cutting fluid on a carbide tool tip is measured using the macroscopic contact angle method. Comparative study of tool wear, cutting force, workpiece surface roughness, and chip thickness among dry machining, machining with conventional cutting fluid as well as nano-cutting fluid has been undertaken. This study clearly reveals that the cutting force, workpiece surface roughness, tool wear, and chip thickness are reduced by the using nano-cutting fluid compared to dry machining and machining with conventional cutting fluid.

Ionic Polymer Metal Composites

Ionic polymer metal composites (IPMCs) are electro-active polymers with excellent electromechanical coupling properties. They are efficient candidates in many advanced technological applications such as actuators, artificial muscles, biomimetic sensors, etc. The manufacturing of electrodes for IPMCs is very critical in their electromechanical coupling. Force optimization, selection of cations and particle size distribution within the IPMC structure, etc. are the various factors, which determines their efficiency. In this chapter, we briefly discuss the structure, components and working mechanisms of IPMCs. The synthesis and characterizations of IPMCs are discussed in detail with the help of examples. A brief outlook on the modeling and potential applications of IPMCs is also included.

Enhancing the metallurgical properties of WC insert (K-20) cutting tool through microwave treatment

Abstract Microwaves are electromagnetic radiation in the frequency range of 300 MHz–300 GHz. For improved performance of products, microwave irradiation becomes an attractive route by way of cost reduction, reduced time and energy savings. In the present study, cemented tungsten carbide (WC) cutting tools were exposed to microwave (2.45 GHz) radiation. Response of the WC tool to microwave radiation has been evaluated in terms of microstructural changes, hardness survey, cobalt phase change through XRD and XPS analysis. Activation of grains, selective heating of WC grains and formation of compound W2C–Co phase have enhanced the metallurgical properties of cemented WC inserts.

Preferential Media for Abrasive Flow Machining

The abrasive flow machining (AFM) is used to deburr, radius, polish and remove recast layer of components in a wide range of applications. Material is removed from the workpiece by a flowing semisolid mass across the surface to be finished. In this study a medium for AFM has been developed from the various viscoelastic carriers and has been contrasted through experimental investigation. The viscoelastic media are selected on the basis of existing media through the studies of thermogravimetric analysis and are characterized by mechanical, as well as rheological, properties with the help of a universal testing machine and a rheometer. The performance of the medium is evaluated through the finishing criteria on a two-way AFM setup. The investigation reveals that the styrene butadiene rubber (SBR) medium gives a good improvement in surface finish. The surface improvement through SBR media is 88%. It is also found that the strain, temperature, shear rate, time of applied constant stress, cyclic loading, etc. have an impact on the mechanical and rheological properties of the newly developed medium, which are ultimately governed by the performance of the medium in the target applications.

Aluminum Substituted Cobalt Ferrite (Co−Al−Fe) Nano Adsorbent for Arsenic Adsorption in Aqueous Systems and Detailed Redox Behavior Study with XPS

Arsenic [As(III) and As(V)] adsorption on aluminum substituted cobalt ferrite (Co-Al-Fe) ternary metal oxide adsorbent is reported by means of qualitative and quantitative spectroscopy tools. IR and Raman active signals were observed around 810-920 cm-1 band indicate different As-OHcomplexed and As-Ouncomplexed stretching vibrations on to the adsorbent. The adsorption behavior of arsenic (III and V) onto these adsorbents is studied as a function of contact time, different concentrations, and pH conditions. The kinetics study on adsorption were performed to understand nature of adsorption which supports the Pseudo Second Order (PSO) model. The adsorption isotherms study indicates Freundlich type of adsorption. The maximum adsorption capacity of Co-Al-Fe adsorbent is observed around 130 and 76 mg g-1 for As(III) and As(V) systems, respectively. Detailed XPS study of As 3d, Fe 2p, Co 2p, and O 1s spectra has been reported in explaining the redox behavior and ligand exchange reactions in supporting arsenic adsorption mechanism.

A Study on Machinability of B-Modified Ti-6Al-4V Alloys by EDM

The effect of microstructural refinement and presence of TiB particles on the electrical discharge machinability of hypoeutectic B-modified Ti-6Al-4V alloys have been studied. This has been characterized on the basis of changes in the following machining responses: material removal rate and tool wear rate. Material removal rate remains unaffected by B addition to Ti-6Al-4V because of insignificant changes in hardness and melting point of the alloy with B modification. On the other hand, microstructural refinement associated with minor amount of B addition leads to enhancement in alloy strength, and hence, tool wear rate has been found to reduce constantly with increasing the amount of B addition. Moreover, the shielding effect of TiB particles, which have higher melting temperature and hardness compared to the Ti-6Al-4V matrix, has also been found to control the wear of the tool.

Excimer Laser Micromachining Using Binary Mask Projection for Large Area Patterning With Single Micrometer Features

Excimer laser micromachining using binary mask projection has been investigated for rapid patterning of single micrometer features over large areas of various substrates. Simple limit for depth of focus that determines the depth to width aspect ratios is given and verified for different materials. Binary mask projection technique is found to conformally reproduce the mask features from the millimetre to the micrometer scale under proper focusing conditions. Large arrays of 1 lm and 15 lm holes on Kapton are made with high resolution and uniform periodicity. Material removal rate (MRR) for the laser machining of these holes are examined and the machining efficiency for these are found to have different dependence on the fluence. A saturation of hole-depth with increasing number of pulses is obtained. [DOI: 10.1115/1.4024880]

Studies on drilling of glass/epoxy laminates using coated high-speed steel drills

Drilling studies were conducted on glass/epoxy composite laminates having two different lay-ups [(0/90)4s and Normal drills (2 flute with cone angle of 118°) made of high-speed steel (HSS), TiN-coated HSS, and TiC-coated HSS were used. Drilling parameters were optimized in terms of least thrust and torque. Parameters studied were thrust, torque, tool wear, form deviation, acoustic emission peak, and root mean square (RMS) of acoustic energy. It was observed that coated HSS drills perform little better than uncoated HSS for small number of holes, while their performance is inferior to uncoated HSS for larger number of holes. This is mainly due to peeling or chipping of the coating from base material (HSS). Also, the performance of TiN-coated HSS drill was observed to be better than TiC-coated HSS.

Micro texturing on metallic surfaces: State of the art

The study of surface texturing on a metallic surface has become a great area of interest of researchers in the last few decades. Surface texturing is employed for enhancing the performance of the surface in its working environment. As the characterization techniques have been evolving very fast, researchers have started mimicking the natural surfaces to take the advantages of their characteristics (such as self-cleaning, load capacity, reducing coefficient of friction). Manufacturing of natural inspired surface requires having a great control over the process to achieve the micro or nano features on the natural surfaces. Hence, the selection of the most suitable process and optimum parameters for machining of arrays of micro or nano features at large scale is highly desirable. This study reports an overview of different micromachining processes used for texturing on metallic surfaces and research gaps to be filled in the available literature. Electrochemical micromachining has tremendous potential on account of its versatility in different applications. It is a promising and economically viable machining process for micromanufacturing industries for fabrication of micro textures and micro features on metallic surfaces. Production of textured surface at large scale requires a sustainable technology, which can serve the purpose of enhancing the performance of the surface without changing the original properties of the surface. Indeed, laser surface texturing, through-mask electrochemical micromachining, lithography, micro- or nanocasting and so on are the existing methods which involve multiple steps for generation of textured surfaces. This article also reports some original experimental investigations for generation of different kinds of micro textures on metallic surfaces, namely, arrays of micro dimples, micro channels and micro pillars using a single-step maskless electrochemical micro-texturing process with a pre-patterned micro tool.

Rheological characterisation and performance evaluation of a new medium developed for abrasive flow finishing

Abrasive action in abrasive flow finishing (AFF) mainly depends on medium formulation and machine settings. Medium composition decides the viscosity and it has significant effect on the process performance. In the present work, a new AFF medium is developed, and experiments are carried out to evaluate its rheological flow properties. Later, AFF experiments are carried-out to finish Al alloy and Al alloy/SiC metal matrix composites with a wide range of input parameters to find-out an appropriate input parameters range to get the best surface finish. Then complete experimental study is planned using central composite rotatable design. The finishing results are correlated with rheological properties of the medium. A change in surface roughness is found to be more in Al alloy/SiCp (10%) as compared to Al alloy and Al alloy/SiCp (15%). Justification for the same has been discussed in the paper.