International Journal of Materials and Product Technology (22 papers in press)
DEVELOPMENT OF AN EMPIRICAL RELATIONSHIP TO PREDICT THE JOINT TENSILE STRENGTH AND JOINT SHEAR STRENGTH OF DIFFUSION BONDED AA6082 ALUMINIUM ALLOY
by Venugopal Sivasankaran, Mahendran G
Abstract: In this work, empirical relationships were developed to predict the joint tensile strength and joint shear strength of the rolled plates made of 5 mm thick aluminum alloy AA6082, joined by diffusion bonding. Three diffusion bonding parameters such as bonding temperature, bonding pressure and holding time were used to formulate the relationship. A central composite design was also put to use to minimize the number of experimental conditions. In addition, the Response Surface Methodology was employed to develop the relationship. The relationship thus developed can effectively predict, to the 95% confidence level, the strength of diffusion bonded AA6082 aluminium alloys. It was observed that the joint tensile strength and joint shear strength went up with the increase in either bonding temperature or bonding pressure. The maximum joint tensile strength and joint shear strength were observed as 36 MPa and 115 MPa at 520
Keywords: AA6082 aluminium alloy; Diffusion bonding; Response surface methodology; Optical microscopy; SEM-EDS.
Machining Characteristics in Cutting Inconel718 with Carbide Tool
by Zhaopeng Hao, Shucai Yang, Yihang Fan, Mingming Lu
Abstract: Nickel-based alloy Inconel718 is widely used in the field of aerospace, owing to its unique properties such as high oxidation resistance and corrosion resistance even at elevated temperature. However, Inconel718 has poor machinability, which mainly includes complex cutting deformation, large and fluctuant cutting force, high cutting temperature and serious tool wear. In this paper, the cutting deformation characteristics of material in cutting zone and tool wear features under different cutting speeds were studied. The physical and chemical phenomena in cutting process and their effects on tool wear were further analyzed. At low cutting speed, the continual generation and falling off of BUE made the cutting process unstable and led to tool chipping. At medium cutting speed, tribo-chemical reaction occurred at tool-chip interface. These new generated and soft metallic oxides attaching to tool surface played a role of boundary lubrication layer. It can reduce the adhesion between tool and chip, thereby protecting the cutting tool. At high cutting speed, inhomogeneous deformation of materials in cutting zone resulted in alternating stress, which led to crack in tool subsurface and made tool material fall off in the form of lamella.
Keywords: Inconel718; cutting deformation; tool wear feature; physical and chemical phenomenon in cutting process.
Fracture Toughness of LLDPE Parts Using Rotational Moulding Technology
by Ramkumar PL, D.M. Kulkarni, V.V. Chaudhari
Abstract: Rotational moulding is a process of producing hollow plastic products. Linear low density polyethylene (LLDPE) is widely used in rotational molding process. Many rotationally moulded LLDPE products are widely used in outdoor applications such as boats, automobile fuel tanks, body armors, riot shields and large solvent drums etc. From quality characterization point of view, fracture properties are considered to be critical for rotationally moulded products. Therefore, it is essential to optimize process parameters for rotational moulding process to yield maximum fracture toughness. In this paper, experimental investigations are carried out by planning and performing trials based on design of experiments (DOE). DOE approach, called response surface method (RSM) is used for data analysis. Oven temperature, oven residence time and cooling medium are selected as principal parameters. Rcurve method is used to characterize the fracture behaviour of rotomoulded products made using LLDPE for various process parameters. Experimental runs and design of experiments (DOE) analysis revealed non-linear effects of process parameters on fracture toughness. From the experimental investigation, optimum process parameters are proposed which yields maximum fracture toughness for rotationally moulded products. The optimum process parameters are oven temperature: 210
Keywords: Rotational Moulding; Process Parameters; Fracture Toughness; LLDPE; Elastoplastic Fracture Mechanics.
Numerical Study on Electromagnetic Crimping of Tubes
by Ramesh Kumar, Sachin D. Kore
Abstract: Electromagnetic crimping process is a non-conventional, high energy, high-velocity, and solid state impact crimping process. In this process, high energy and high-density electromagnetic field were used to accelerate and impact the flyer tube onto the base tube. A sequential coupled electromagnetic field analysis of electromagnetic crimping was performed using finite element method and boundary element method in the LS-DYNA software. In this study, three types of actuators having cross-sections namely circular, rectangular and square were modeled and analyzed for electromagnetic crimping of aluminum Al 3003 and 4340 steel tubes. For this study, the length, number of turns, the pitch and the magnitude of a cross-sectional circumference of the actuators were kept constant. Process parameters such as discharge voltage, standoff distance, and actuator cross-section were varied in this study. Properties like a magnetic field, plastic strain, current density, radial deformation, impact velocity, Lorentz force and Tresca maximum shear stress developed in the flyer tube were compared with all three types of actuators and it was found that the actuator with square cross-section gives the better results. From this study, it was observed that the use of the square cross-section coil is more efficient than that of the circular or rectangular cross-section.
Keywords: electromagnetic crimping; numerical modelling; plastic deformation; boundary element method; flyer tube; actuator cross-section.
ARTIFICIAL NEURAL NETWORK BASED CONTROL STRATEGIES FOR PMSG BASED GRID CONNECTED WIND ENERGY CONVERSION SYSTEM
by Ramji Tiwari, Ramesh Babu N
Abstract: This paper presents a novel control strategy employing the artificial neural network based direct torque control strategy (DTC) and direct power control strategy (DPC) for permanent magnet synchronous generator (PMSG) based wind energy conversion system (WECS). The Aeolos 3 kW wind system ratings are considered in this paper for real time system validation. The proposed control strategy combines artificial neural network (ANN) based DTC as machine side control strategy (MSC) and ANN based DPC as grid side control strategy (GSC) in order to track the maximum power and to regulate the active power respectively. To generate the switching pulse for the converter in generator side and grid side, a neural network based technique is employed. Furthermore, the DC link voltage is optimized using the GSC topology. The proposed controller provides an effective solution for grid integration and constant power flow from the generator system to the grid system. The proposed co-ordinate control strategy is validated using MATLAB/Simulink software to analysis the working condition. The experimental test bench is implemented using dSPACE to study the real time analysis of the proposed control strategy.
Characterization of Silica Derived from Rice Husk Ash and Nickel Oxide at Different Composition and Temperatures
by Rizamarhaiza Muda, Sufizar Ahmad, Mohd Azham Azmi, Nooriati Taib, Hariati Taib
Abstract: Nickel supported on silica compatibility and density found to be active for producing stoichiometric amounts of hydrogen and carbon in gas catalyst. In this study, the Silica (SiO2) derived from Rice Husk Ash (RHA) and Nickel Oxide (NiO) bodies with varying composition were highlighted. The highlighted compatibility studies of naturally derived SiO2 from RHA to be applied in the gas catalyst were investigated. The compositions of SiO2 involved in this study were 50 wt% and 90 wt% sintered at four different temperatures of 800
Keywords: Rice Husk Ash; Silica; Nickel Oxide; Polyvinyl alcohol; Powder Metallurgy; X-Ray Diffraction; X-Ray Florescence; Density; Sintering Temperature ; Amorphous; Crystalline.
OPTIMIZATION OF EDM PROCESS PARAMETERS FOR AA7050-10 (WT) % B4C COMPOSITE THROUGH ARAS, GREY AND TAGUCHI TECHNIQUE
by ARVIND KUMAR, Ram Naresh Rai
Abstract: The growing demand for high strength-to-weight ratio material has raised the interest to develop Al/B4C composite. Nevertheless, these materials are hard to machine through the conventional machining process. Therefore, to obtain close tolerance for machined components the selection of non-conventional machining process is desirable. The present paper discusses the development of AA7050-10(wt.) % B4C Composite through flux assisted stir casting method. The developed composite undergone microstructural study to ensure the distribution and incorporation of reinforcement particles into the matrix. Die Sinking Electro Discharge Machine used to machine the developed composite. The Taguchi L16 orthogonal array was used to design the experiment to obtain Material Removal Rate (MRR), Surface Roughness (SR) and Tool Wear Rate (TWR) as machinability measure by considering the concurrent effect of various process parameters. The collected responses were optimised using Additive Ratio ASsessment (ARAS) and Grey Relation Analysis (GRA) and Taguchi Analysis. Analysis of variance (ANOVA) was conducted to identify the significance of each process parameters on the responses. Pulse current of 16 A, pulse on time of 200
Keywords: AA7050-B4C Composite; ARAS; Grey Relation Analysis; EDM; Taguchi; ANOVA.
Special Issue on: Developments in Additive Manufacturing
Investigations on the melt flow behavior of aluminium filled ABS polymer composite for the extrusion-based additive manufacturing process
by Narendra Kumar, Prashant K. Jain, Puneet Tandon, Pulak M. Pandey
Abstract: In extrusion-based Additive Manufacturing (AM) process, the Melt Flow Rate (MFR) of material plays a significant role in determining the suitable process parameters for printing parts. MFR of the polymers varies on the addition of fillers which eventually leads to alteration in the pre-set values of process parameters. The present study deals with the evaluation of MFR of Aluminium (Al) filled Acrylonitrile Butadiene Styrene (ABS) polymer matrix composite using melt flow index tester for extrusion-based AM process. L16 Taguchi OA method was used to design the experiments considering three factors and four levels. Extrusion temperature, extrusion load and filler loading (wt.% of Al) were considered as the input factors, while MFR was selected as the measured response. Furthermore, the significance of each factor was determined using Analysis of Variance (ANOVA) and Signal to Noise (SN) ratio techniques. Experimental results indicated the improvement in the MFR for 10wt.% Al filled ABS composite. However, the opposite trend in MFR was observed for other combinations of ABS/Al. Based on obtained MFR results, process parameters were established to print parts of developed ABS/Al composite through a customized extrusion-based AM process. The present study may be useful in the fabrication of customized lightweight conductive structures.
Keywords: 3D printing; additive manufacturing; pellet; screw extrusion; melt flow rate; fused deposition modeling; ABS; Aluminium; polymer composite.
Synthesis, Analysis and 3D Printing of Flapping Mechanisms
by Balasubramanian E, Chandrasekhar U, Siva Sakthi Velan S, Lung-Jieh Yang, Sachin Salunkhe
Abstract: This paper presents a methodology for designing of flapping mechanisms and rapid fabrication using 3D printing (3DP) technique for subsequent application in micro aerial vehicles. A key feature of the present study is constraining of the mechanism weight and aerial vehicle size to stipulated limits while optimising the functional features of flap angle, flapping frequency and lift. These contradictory set of requirements are fulfilled through syntheses involving linkage number, linkage type and dimensions. As geometrical features are intricate and the required quantity is small, 3DP techniques of fused deposition modelling and digital light processing (DLP) of photopolymers are used as fabrication options. Assembly integration studies are carried out using 3DP parts and the practical feasibility of the suggested approach as a potential alternative to traditional injection moulding is established. Performance evaluation of the developed mechanism indicates conformance with design intent. The presented methodology demonstrates a novel avenue for rapid realisation of an important class of flapping aerial vehicles that have wide ranging applications in surveillance missions.
Keywords: Flapping frequency; Flap angle; Kinematics; Synthesis; 3D Printing.
Development of light weight multi-rotor UAV structures through synergistic application of design analysis and fused deposition modelling
by Balasubramanian Esakki, Sagar N V S S, Chandrasekhar Udayagiri, Sachin Salunkhe
Abstract: Additive manufacturing (AM) technologies are gaining acceptance for fabricating end-use parts in several sectors and this study focuses on developing AM based approach for gainful development of unmanned aerial vehicles (UAV). Design-freedom and time-compression are synonymous with AM technologies and to realise the same in the development of UAVs, redesigning of the components is imperative. This paper presents a protocol that synergistically combines design iterations and fused deposition modelling (FDM) for developing light-weight structures for multi-rotor UAVs. Rather than employing expensive industry-grade FDM systems, the present study illustrates a fabrication protocol based on desktop 3D printers and affordable FDM filament material of polyactic acid (PLA). Multiple design configurations are analysed and prototyped leading to considerable weight reduction. The resultant operational benefits that are related to lesser part count, lower assembly effort and higher flight duration as compared to the conventional designs are demonstrated through experimental efforts. A customised process for electrochemical deposition of copper-nickel layers over the PLA parts is developed for enhancement in tensile, flexural and impact performance. Findings from this study lead to new vistas for rapid design iterations through an AM centric fabrication process with consequential impact on ever burgeoning UAV domain.
Keywords: Additive Manufacturing; Unmanned Aerial Vehicles; Fused Deposition Modelling; Electrochemical Deposition.
Decision making methodology for the selection of 3D printer under fuzzy environment
by Raghavendra Prabhu Sundarraj, Ilangkumaran Mani
Abstract: The eventual goal of this paper is to assess the proficiency of three-dimensional (3D) printers to produce automotive parts. This work is to label the application of Hybrid- Multi Criteria Decision Making (HMCDM) techniques for resolving the 3D printer selection problem for manufacturing of automotive parts. Fuzzy Analytical Hierarchy Process (FAHP), FAHP- VIseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) and FAHP- ELimination and Choice Expressing REality (ELECTRE) are the MCDM methods used for evaluation and ranking of the 3D printers. Totally ten different 3D printers alternatives such as Lulzbot Taz 5 (Z1), Ultimaker 2 (Z2), Zortrax (Z3), Wanhao Duplicator 4 (Z4), Airwolf 3D AW3D HD2X (Z5), Flashforge creator X (Z6), Makerbot Replicator orginal (Z7), Delta non turbo WASP (Z8), Artifex duo 2 (Z9), UP plus 2 (Z10) and six evaluation criteria such as volume (C1), printing Speed (C2), thickness of the layer (C3) , Extruder(s) (C4), machine cost (C5), cost of the filament material (C6) are motivated in this study to choose the appropriate 3D printer from the alternatives. The fourth alternative Wanhao Duplicator 4 (Z4) has achieved the top spot among the alternatives using the suggested methodologies.
Keywords: 3D printer; MCDM; FAHP; ELECTRE; VIKOR.
Mechanical capabilities of semi-rigid thermoplastics ABS and PLA from 3D printing
by Jaime Molina Osejos, Cesar Ayabaca Sarria, Diana Peralta Zurita, Santiago Gómez Rosero, Gustavo Moreno Jimenez
Abstract: The use of 3D printing is more common in industries, such as textiles, food, aeronautics, automotive, medicine and others, because of its great versatility during the manufacturing process generation of elements or components with high geometric complexity in relatively short time at low cost. This study presents the characterization of semi-rigid Acrylonitrile Butadiene Styrene (ABS) and Polylactic Acid (PLA), which were obtained using both of additive manufacturing and specifically the molten material deposition method. The semi-rigid samples were made with 5 different infill patterns in their interiors: triangle, square, pentagon, circles.
The samples were subjected to tensile and bending tests, which allowed the evaluation of the yield strength, ultimate tensile strength, deformation and modulus of elasticity. Also, ASTM D638-14 and ASTM D790-10 norms were used for methodology validation. The results determined that the distribution of concentric circles with 7,964 MPa / g and 12,234 MPa / g. was the best for PLA and the square with 8.82 MPa / g and 8,994 MPa / g was the best for ABS respectively.
Keywords: ABS; PLA; material characterization; 3D printing; yield strength; deformation.
Special Issue on: A Synergistic Approach in IR4.0 for Product Technology Development
Characterization of microstructure, mechanical properties and fracture mode of the dissimilar joining of AISI 304 stainless steel and DP780 dual phase steel by resistance spot welding
by Masoud Sabzi, Sadegh Moeini Far , Saeid Mersagh Dezfuli
Abstract: Microstructure, mechanical properties and fracture mode were investigated for the dissimilar joining of AISI 304 steel and DP780 steel by resistance spot welding. First resistance spot welding was utilized with a current density of 8kA, holding time after welding of 10 cycles, and 5kN electrode force. Then, to evaluate the microstructure, hardness profile and tensile-shear strength of weld nugget, scanning electron microscopy (SEM), Vickers micro-hardness and tensile-shear tests were carried out, respectively. Microstructural evaluations showed that in the dissimilar joining of DP780 - AISI 304 stainless steel, fusion zone (FZ) microstructure was martensitic and some grains were also coarsened in heat affected zone (HAZ). Moreover, HAZ in AISI 304 stainless steel side remained completely austenitic, while HAZ in DP780 dual phase steel transformed to martensite. Micro-hardness results showed that in the dissimilar joint of DP780 - AISI 304 stainless steel, FZ hardness was higher than base metals (BM) of both sheets of steel. Additionally, HAZ in DP780 dual phase steel side had higher hardening ability than other joint areas. Results of tensile shear tests of the dissimilar joint of DP780 - AISI 304 stainless steel, indicated that the joint had the tensile shear strength of 15 kN along with the occurrence of severe plastic deformation.
Keywords: Resistance spot welding; DP780 dual phase steel; AISI 304 stainless steel; Microstructure; Hardness profile; Tensile – shear strength.
Effect of Ball Milling Time on the Properties of Nickel Oxide-Samarium-Doped Cerium Composite Anodes for Solid Oxide Fuel Cells
by N.O.R. FATINA RADUWAN, Muhammed Ali S.A., Mustafa Anwar, Andanastuti Muchtar, Mahendra Rao Somalu
Abstract: The powder characteristics of composites under different processing conditions, such as milling time, must be elucidated before fabricating electrodes with porous structures for fuel cell applications. Milling time is an important parameter in producing pure composite powders with fine crystallite size and affects the densification of the sintered pellet and the electrical performance of the cell. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses were conducted to characterize nickel-oxidesamarium-doped cerium (NiO-SDC) powders milled for different durations (2, 12, and 24 h). Field-emission scanning electron microscopy (FESEM) analysis was performed to clarify the porosity of the sintered pellets. Density was determined using Archimedes method and was found to decrease after the reduction of the anode pellets. The XRD analysis of the composite anodes showed good chemical compatibility between the NiO and SDC. The TEM analysis of the as-prepared powders indicated that the particle size of the powder was within the nanometer range. This finding was confirmed by the FESEM micrograph of the sintered pellets. The porosity of the sintered pellets (before and after reduction) ranged from 20% to 40% and was considered sufficient for anode materials in solid oxide fuel cells (SOFC).
Keywords: ball milling time; NiO-SDC; composite anode; particle size; porosity; density; solid oxide fuel cell.
Characterization of four-layered Al-Al2O3 functionally graded material prepared through powder metallurgy and pressureless sintering
by Farah Fazira Kamaruzaman, Dewan Muhammad Nuruzzaman, Mohammad Asaduzzaman Chowdhury, Siti Nur Sakinah Jamaludin, Shahnor Basri, Noor Mazni Ismail
Abstract: In this research study, four-layered aluminium-aluminium oxide (Al-Al2O3) functionally graded material (FGM) was prepared through powder metallurgy (PM) route considering 0%, 10%, 20% and 30% weight percentage of ceramic concentration. The main objective of this study was to investigate the microstructure of the prepared samples layer by layer and to characterize the samples qualitatively and quantitatively. The FG samples were fabricated using cylindrical steel die under 30 ton compaction load. The FG samples were then sintered using pressureless sintering. The sintering temperature and time used are 620oC and 120 min following two-step sintering cycle. The prepared FGM samples were characterized by densification and shrinkage. Microstructural and elemental analyses were carried out by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Mechanical characterization was carried out using vickers microhardness tests. It was observed that cylindrical FGM specimens (green compact) were successfully prepared and diameter of cylindrical structure was decreased after sintering process. It was also observed that there was no existence of macro-crack or micro-crack within the individual layer or at the interface and smooth transition occurred from one layer to next layer. Elemental analyses confirmed the gradient distribution of material composition layer by layer. Moreover, the obtained data showed that increase in hardness occurred layer by layer with the increase in Al2O3 content.
Keywords: characterization; functionally graded material; pressureless sintering; aluminium; aluminium oxide.
The Weighting of Product Design Specification for a Composite Side Door-Impact Beam Using the Analytical Hierarchy Process Method
by MOHD ADRINATA SHAHARUZAMAN, Mohd Sapuan Salit, Muhd Ridzuan Mansor, Mohd Zuhri Mohamed Yusoff
Abstract: Multiple criteria decision making (MCDM) has been widely used in engineering and technology areas to provide a solution when making a decision. Weight of criteria is one of the important pieces of information required to obtain successful MCDM results. Nevertheless, in many MCDM problems, the procedure to determine the weighting criteria is not specifically defined, which may create decision inconsistency in the final results. In this study, the Analytic Hierarchy Process (AHP) method is employed to determine the weightage criteria for product design specification (PDS) of a side-door impact beam. The advantages of AHP are its ability to assist decision makers in performing systematic judgment to evaluate weightage criteria and the consistency of the judgments made, especially for problems involving multiple decision makers. Out of seven PDSs collected from literature, six criteria have been chosen to be judged using the AHP pairwise comparison technique by ten decision makers from an automotive engineering and product design background. The results of weightage criteria by decision makers have been calculated and recorded. The results show that performance has the highest weightage, which is 0.3566, follows by product cost and weight with the values of 0.1971 and 0.1690, respectively. Environment and disposal are at fourth (0.1127) and fifth (0.0857) places, respectively, whilst size generates the lowest weightage (0.0789). Validation of the results using the AHP consistency ratio (CR) also shows the obtained average CR value is below 0.1, which proves that the decision makers judgment is consistently high. In conclusion, this study indicates that the utilization of the AHP method can assist in systematically determining the weightage criteria in the MCDM method for product design and development of side-door impact beam components.
Keywords: Analytic Hierarchy Process (AHP); multiple criteria decision making; side-door impact beam; weightage criteria.
A systemic study on hydroforming process of exhaust pipe FE simulation and experiment
by Kuanxin Liu, Ning Guo, Shunqi Zheng, Kemin Xue
Abstract: Hydroforming process of tube parts is widely used in many industries due to the virtues of weight reduction and high strength and stiffness. The exhaust pipe hydroforming process is investigated systemically combined FE simulation with experiments. The FE simulation model for hydroforming process is established after solving several key technologies based on the ABAQUS software, and the validation is carried out compared with experiments. And then, the effects of process parameters on forming quality are studied by using the FE simulation model. The optional process parameters are obtained based on the simulation model and orthogonal experimental analysis. Finally, three typical loading paths are proposed and tested, and the guidance for loading path is given. Based on these developments, the exhaust pipes are manufactured by hydroforming in a short period and low cost.
Keywords: hydroforming process; exhaust pipe; optional process parameter; orthogonal experimental analysis.
Characterising the strength of solid and honeycomb geometrical plates under quasi-static loading
by Nik Muhammad Azif Arifin, Abdul Hadi Azman
Abstract: This paper presents the strength characteristics of solid and honeycomb plates under quasi-static loading using finite element analysis (FEA). The aim was to investigate and compare the strength characteristics of solid and honeycomb plates. A comparison of these simulations was conducted based on the strength of material characteristics prediction. Geometrical models for the solid and honeycomb plates subjected to uniform stress were developed and assessed. The effects caused by quasi-static load were studied by comparing the two plates to obtain the stress and translational displacement. The simulations were elastic and the deflection of the solid and honeycomb plates were determined. The results were similar with a deflection of 11.4 mm for the solid plate and 11.3 mm for the honeycomb. However, the stress results
were different. Therefore, this comparison method is suitable for evaluating other mechanical structures in the field of strength of materials.
Keywords: honeycomb plate; quasi-static; translational displacements; solid plate; von Mises stress.
Special Issue on: Cambridge Summit 2018 Advances in Engineering Systems and Product Technology
Effect of nano-yttria dispersion on the microstructure and mechanical properties of W-Ni-Co alloys
by Pandi Selva Durai C, Arul Mozhi Selvan Varadappan
Abstract: In this study, effect of nano-Y2O3 (0.25-0.75 wt.%) addition in tungsten heavy alloy which consists of 93wt.% tungsten and Ni/Co ratio fixed at 9 was investigated. Ni, Co and Y2O3were mixed in high-energy ball milling in order to obtain nanostructure and this mixture subsequently blended with tungsten (W) in a low energy ball milling. The powder mixture was consolidated by cold-isostatic pressing (CIP) and the green compact was sintered at 1475
Keywords: Cold isostatic pressing; Contiguity; High-energy ball milling; Nano Y2O3; W-Ni-Co heavy alloy.
Experimental investigations and optimization of process parameters in dry finish turning of Inconel 625 super alloy
by S. Hemakumar, P. Kuppan
Abstract: This study presents an experimental investigation and optimization of process parameters in finish dry turning of Inconel 625 nickel based super alloy. The process parameters such as cutting speed and feed rate were varied for three levels keeping depth of cut constant at finish machining regime (0.5 mm). The experiments were conducted as per the full factorial design of experiments and the influence of process parameters on the output measures such as cutting force (FC), feed force (Ff), average surface roughness (Ra) and average flank wear (VB), were analyzed using ANOVA. Empirical models were developed for the output measures using Response Surface Methodology and the regression analysis shows a good degree of fit. The optimal conditions for minimum Ra and VB were obtained through response optimization Composite Desirability approach. Furthermore the tool wear mechanism was studied and reported.
Keywords: composite desirability approach; dry machining; cutting force; Inconel 625; response surface methodology; surface roughness; tool wear.
Random Dopant Fluctuations Impact reduction in 7 nm Bulk-FinFET by Substrate Engineering
by Jegadheesan V, Sivasankaran K, Aniruddha Konar
Abstract: Currently Fin-Field-Effect-Transistors (FinFETs) are used at 7 nm technology node, in order to avoid parasitic leakage channel under the controlled channel Punch-Through-Stopper (PTS) doping is used with the bulk Silicon substrate (PTS-Si substrate). The dopants from PTS doping enters into the channel during the annealing process and increases channel doping level. The increased doping concentration in channel causes undesirable effects such as reduction in channel mobility and increase in Random-Dopant-Fluctuations (RDFs). Using a Silicon-On-Insulator substrate (SOI substrate) is a costlier solution, this work presents Super-Steep-Retrograde-Silicon substrate (SSR-Si substrate) as a better solution for this problem. In this work, the SSR-Si substrate is achieved by placing lightly doped 10 nm thick SSR-buffer layer (Silicon) on top of PTS-Si substrate. This SSR-buffer layer captures dopants intruding from PTS doping into channel thereby achieves SSR doping profile in the channel. The results show SSR-Si substrate reduces the RDF induced threshold variations by 50%, it also provides better DC and RF/analog metrics than PTS-Si substrate and comparable with SOI substrate.
Keywords: FinFET; RDF; SIFM; Statistical variations;.
Coupling reduction of two element MIMO Antenna using parasitic element for LTE Band Application
by A.Christina Josephine Malathi, Thiripurasundari D
Abstract: This paper presents a two triangular patch MIMO antenna using parasitic element for enhancing isolation which is aimed to function in the LTE band covering from 1.7 to 3.6 GHz. The parasitic element is a planar interdigital line structure placed between the patches on top of the substrate. The antenna covered an impedance bandwidth of (1.5 to 3.58) GHz with return loss of -18.16 dB and -12 dB at 2.26 and 3.25 GHz during simulation. A fractional bandwidth of 92% was achieved. An isolation of -20 dB and -20.5 dB was observed during simulation at 2.26 GHz and 3.25 GHz. The proposed antenna was fabricated and tested. It provided a bandwidth of (1.8 to 2.27) GHz & (3.2 to 3.3) GHz with return loss of -18.28 dB and -10.64 dB respectively. An isolation of -25.5 dB at 2.26 GHz and -20.5 dB at 3.25 GHz was observed during measurement amid the ports with a close by spacing of 0.074λ between antenna elements. With a very close by spacing the proposed antenna exhibits a better performance compared to the previously reported designs in the literature by providing 53.3% less space. The antenna had good radiation characteristics in both E-plane and H-plane for all the operating frequencies.The simulated envelope correlation coefficient is below 0.002 and the total active reflection coefficient is below 0.40 throughout the band with a gain of 2.28 dB and 4.30 dB during simulation and 2 dB & 3.23 dB in measurement at 2.26 and 3.25 GHz.
Keywords: Gain; long-term evolution (LTE); envelope correlation coefficient (ECC); return loss; multiple input multiple output (MIMO); Total Active Reflection Co-efficient (TARC).