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G. Rajashekar Reddy ¹, Sunil Magadum ², M. Chellamalai ², N. Balashanmugam ²

Affiliations
1 Dept. of Mech. Engg., NITK, Surathkal, IN
2 Central Manufacturing Technology Institute (CMTI), Bangalore, IN

Abstract

Femtosecond laser micromachining of rectangular grooves on AISI3415 steel is investigated at 150 fs pulse duration and at a wavelength of 775nm. In the present work, Laser process parameters such as spot size, feed rate and number of passes are optimized considering the multiple responses such as surface roughness (Ra) and depth of groove based on orthogonal array with grey relational analysis. A grey relational grade is calculated using grey analysis and process parameters are optimized based on signal to noise ratio. To validate the experimental result, verification test is performed. Experimental outcomes have proved that the responses in femtosecond laser micromachining can be enhanced efficiently through this approach.

Keywords

Femtosecond Laser, Micromachining, Laser Spot Size, Taguchi Grey Relational Analysis.

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Sunil Magadum ¹, M. Chellamalai ², N. Balashanmugam ¹

Affiliations
1 Central Manufacturing Technology Institute (CMTI), Tumkur Road, Bengaluru, IN
2 Ultra Precision Engineering Dept, Central Manufacturing Technology Institute (CMTI), Tumkur Road, Bengaluru, IN

Abstract

Since its invention in 1960, laser has been widely used in many fields, such as scientific research, medical treatment, industry and military. Excimer lasers are an important family of gas lasers that were firstly commercialized in the 1970s. The most common excimer lasers use rare-gas monohalides such as KrF, ArF & XeCl and have a wavelength in ultraviolet (UV) range. The applications of excimer laser are very broad with new applications continuously coming out. This paper addresses novel applications of an excimer laser (248 nm & 193 nm wavelength, 20 ns pulse duration) in micromachining.

Keywords

Excimer Laser, Micromachining, MEMS, HAZ.

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M. Chellamalai ¹, Gowtham Hegde ², V. R. Raju ¹

Affiliations
1 Ultra Precision Engineering Department, Central Manufacturing Technology Institute (CMTI), Tumkur Road, Bangalore, IN
2 National Institute of Technology Karnataka, Surathkal, IN

Abstract

The micro electro discharge machining process, the erosive action of an electrical discharge between electrode and workpiece is used to remove material. Electro-thermal erosion creates small craters both in the workpiece and the tool during machining progress, with this technique excessive electrode wear leads to increased gap size between the tool and workpiece results inconsistent performance. Understanding the electrode wear and influencing factors are crucial to more accurate and reliable micro EDM process. This paper presents an electrode wear of different electrode material such as Copper, Copper-Tungsten, Brass, and Graphite at different micro EDM parameters were analyzed. The objective of this study is to know the electrode wear and surface roughness of the different electrode material, in the micro EDM machining process. The effect of electrode wear rate (EWR) and surface roughness (R_a) has been investigated for Stainless Steel work piece material and the different electrodes such as Copper, Brass, Copper-Tungsten, Graphite. The shape of the different electrodes is ball nose type. Experiments were repeated for different gap voltage values and the different electrode materials. Micro EDM machine Model DT-110 is used for the experimentation. The work materials which are difficult to machine like heat treated tool steels, composites, super alloys, and ceramics can be easily machined in μEDM process. This study investigates the results of a various experimental parameters such as voltage, capacitance on material removal rate, electrode wear rate and surface quality of Stainless Steel 304 in the micro EDM process.

Keywords

Micro EDM, Surface Roughness, Electrode Wear Rate, Micro Machining.

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V. R. Raju ¹, C. K. Srinivasa ¹, A. R. Vinod ¹, M. Chellamalai ¹, P. V. Shashikumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

Electrical Discharge Machining (EDM) is one of the non-conventional machining processes used for machining of electrically conductive materials. Mechanism of material removal in EDM is based on conversion of electrical energy into thermal energy. In this paper, copper electrodes of diameter 0.1, 0.4 and 0.8 mm were used for machining holes on steel work-piece to a depth of 0.2 mm by micro-EDM process. Experiments were conducted at a capacitance of 0.001, 0.01, 0.1 and 0.4 μF with a gap voltage of 80 V and the electrode was rotated at 100 rpm during ED machining. Wear on the electrode; surface roughness and the size of the machined hole were measured. Capacitance had a profound influence on the material removal rate, volumetric wear ratio, spark gap and surface roughness of work-piece.

Keywords

EDM, Micro-Holes, Electrodes, Wear, Capacitance, Spark Gap.

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M. Chellamalai ¹, Ali Maruf Hassan ¹, G. Ugrasen ¹, P. V. Shashi Kumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Bangalore, IN

Abstract

Conventional dressing methods available commercially are single point and roller dressers. Dressing is essentially a sharpening operation designated to generate a specific topography on the working surface of the grinding wheel. These techniques have seldom been satisfactory for super abrasive wheels. There are problems of high dresser wear, insufficient grain protrusion, improper generation of profiles, stresses being induced into wheels, time consuming, shortcomings of loading induced deformation&shape distortion and very low dressing efficiencies. Numerous works have been published on the feasibility of laser dressing of grinding wheels till now. Based on the reports and research works, the present effort has been to actualize the same conditions of laser dressing in actual high speed grinding conditions. The work presents a favourable and opportune environment for the technology of laser dressing to shape into reality.

Keywords

Superabrasive, Grinding Wheel Dressing and Pulsed Fiber Laser.

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N. S. Balaji ¹, S. Jayabal ¹, S. Sathiyamurthy ², T. Krishnan ³, M. Chellamalai ⁴

Affiliations
1 Dept. of Mechanical Engg., A C College of Engg. and Technology, Karaikudi, IN
2 Dept. of Mechanical Engg., Sri Ramanujar College of Engg., Kolapakkam, Chennai, IN
3 Dept. of Mechanical Engg., Annamalai Polytechnic College, Chettinad, IN
4 Central Manufacturing Technology Institute (CMTI), Bangalore, IN

Abstract

The mechanical properties of synthetic glass and natural sisal fiber-reinforced polyester laminates were evaluated in this investigation. The drilling operations were performed in the fabricated synthetic and natural fiber composites using CNC milling machine with measuring set up. The effect of input parameters such as point angle, spindle speed and feed rate on the drilling responses namely delamination factor, temperature in the drilling zone and noise level during drilling were analyzed. A systematic fuzzy model was developed to predict the drilling responses for varying drilling conditions in glass-polyester and sisal-polyester composite laminates.

Keywords

Fuzzy Logic, Polyester Resin, Delamination Factor, Temperature, Noise Level.

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S. Sathiyamurthy ¹, A. Syed Abu Thaheer ², S. Jayabal ³, M. Chellamalai ⁴

Affiliations
1 Dhaanish Ahmed College of Engg, Chennai, IN
2 Mohamed Sathak Engg College, Kilakarai, IN
3 A. C. College of Engg and Technology, Karaikudi, IN
4 Central Manufacturing Technology Institute, Bangalore, IN

Abstract

The tensile, flexural and impact properties of coir fiber-reinforced polyester composites for different levels of fabrication parameters were evaluated. The nonlinear regression models of tensile, flexural and impact properties were developed using Response Surface Methodology (RSM) approach and optimum fiber parameters were determined using Particle Swarm Optimization (PSO) technique in this investigation.

Keywords

Mechanical Properties, Polyester Matrix, Response Surface Methodology, Particle Swarm Optimization.

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P. R. Periyanan ¹, U. Natarajan ², P. V. Shasi Kumar ³, M. Chellamalai ³, S. Gopikrishna ³

Affiliations
1 Sudarshasan Engineering College, IN
2 A C College of Engineering & Technology, IN
3 Central Manufacturing Technology Institute, Bangalore, IN

Abstract

There is a growing demand for industrial products not only with increased number of functions but also of reduced dimensions. Micro-machining is an emerging technology for the production of such miniaturized parts and components. In this present trend, new fabrication methods for producing miniaturized components are gaining popularity due to the recent advancements in micro electro mechanical systems (MEMS). Micro manufacturing include both conventional and nonconventional material removal process. The conventional machining process like micro-drilling, micro-milling etc. are used in fabricating micro components. The non-conventional process includes etching, various lithographic techniques like LIGA and laser micro machining etc. This literature report focuses on the recent trends in micro machining processes, process parameters and its quality characteristics.

Keywords

Micromachining, Cutting Tools, Cutting Forces, Cutting Fluid, Tool Wear.

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S. Jayabal ¹, U. Natarajan ¹, S. Sathiyamurthy ², V. Thirukumaran ³, M. Chellamalai ⁴

Affiliations
1 Dept. of Mechanical Engg., A. C. College of Engg. and Technology, Karaikudi, IN
2 Dept. of Mechanical Engg., Dhaanish Ahmed College of Engg., Chennai, IN
3 Dept. of Mechanical Engg., Sri Raaja Raajan College of Engg. and Technology, Karaikudi, IN
4 Central Manufacturing Technology Institute, Bangalore, IN

Abstract

The development of natural fiber composites in India is based on a two-pronged strategy of preventing depletion of forest resources as well as ensuring good economic returns for the cultivation of natural fibers. This paper analyzed the possible applications of coir fiber reinforced composites for manufacturing Engineering components. The coir fiber reinforced composites were manufactured using hand lay-up process using treated coir fibers and polyester resin matrix. The three mechanical properties such as tensile strength, flexural strength and Impact strength were tested as per ASTM standards. The manufactured engineering components are presented and possible applications are also suggested in this investigation.

Keywords

Tensile Strength, Flexural Strength, Impact Strength, Polyester Resin.

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S. Sathiyamurthy ¹, A. Syed Abu Thaheer ², U. Natarajan ², P. V. Shashikumar ³, M. Chellamalai ³

Affiliations
1 A C College of Engg. and Technology, Karaikudi, IN
2 Dept. of Mechanical Engineering, A C College of Engg. and Technology, Karaikudi, IN
3 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

In this paper, the influence of micro-EDM-drilling process variables on surface roughness using an integrated multi-process micro machining machine (IMMM) is presented. The machining parameters considered are feed rate, capacitance & voltage and response parameter is surface roughness. Experiments are designed as per full factorial design using Design of experiments. Response surface methodology approach is used for modeling the surface roughness and finding out the optimal values of drilling parameters. The influence of each drilling parameter in micro-EDM process is characterized and the optimum value of parameters is determined. The interaction effects of parameters on surface roughness are discussed and the mathematical model and optimized parameters are validated for micro-EDM-drilling process.

Keywords

Surface Roughness, Full Factorial Design, Response Surface Methodology Micro-EDM.

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Sunil Magadum ¹, K. Niranjan Reddy ¹, M. Chellamalai ¹, N. Balashanmugam ¹

Affiliations
1 Central Manufacturing Technology Institute (CMTI), Bengaluru, Karnataka, IN

Abstract

Standard glass scale is just like a kind of very precise ruler and on its surface, accurate divisions are equally marked. The standard glass scales are frequently used in calibration of precise instruments with non contact method of measurements like optical microscopes, video microscopes, profile projectors etc. With the help of ultra fast pulsed laser micromachining system devised a state of the art process for manufacturing standard glass scales. The machined standard scales were calibrated using F25 CMM for 10 mm range scale and Profile projector for 150 mm range scale. The results of the calibration shows the accuracy of the Glass scales at par with the scales manufactured by photolithography process.

Keywords

Standard Glass Scale, Gratings, Stage Micrometers, Ultra Fast Pulsed Laser.

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