International Journal of Manufacturing Engineering http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Studies on the Process Parameters of Rapid Prototyping Technique (Stereolithography) for the Betterment of Part Quality Thu, 11 Dec 2014 00:10:21 +0000 http://www.hindawi.com/journals/ijme/2014/804705/ Rapid prototyping (RP) has evolved as frontier technology in the recent times, which allows direct transformation of CAD files into functional prototypes where it tremendously reduces the lead time to produce physical prototypes necessary for design verification, fit, and functional analysis by generating the prototypes directly from the CAD data. Part quality in the rapid prototyping process is a function of build parameters such as hatch cure depth, layer thickness, orientation, and hatch spacing. Thus an attempt was made to identify, study, and optimize the process parameters governing the system which are related to part characteristics using Taguchi experimental design techniques quality. The part characteristics can be divided into physical part and mechanical part characteristics. The physical characteristics are surface finish, dimensional accuracy, distortion, layer thickness, hatch cure, and hatch file, whereas mechanical characteristics are flexural strength, ultimate tensile strength, and impact strength. Thus, this paper proposes to characterize the influence of the physical build parameters over the part quality. An L9 orthogonal array was designed with the minimum number of experimental runs with desired parameter settings and also by analysis tools such as ANOVA (analysis of variance). Establishment of experimentally verified correlations between the physical part characteristics and mechanical part characteristics to obtain an optimal process parameter level for betterment of part quality is obtained. The process model obtained by the empirical relation can be used to determine the strength of the prototype for the given set of parameters that shows the dependency of strength, which are essential for designers and RP machine users. Raju Bangalore Singe Gowda, Chandra Sekhar Udayagiri, and Drakshayani Doulat Narendra Copyright © 2014 Raju Bangalore Singe Gowda et al. All rights reserved. Experimental Investigation and Multiobjective Optimization of Turning Duplex Stainless Steels Wed, 03 Dec 2014 00:10:03 +0000 http://www.hindawi.com/journals/ijme/2014/921081/ This paper addresses experimental investigations of turning EN 1.4462 and EN 1.4410 duplex stainless steel grades with multilayer coated carbide inserts. Single-point wet and dry longitudinal turning tests of cylindrical bars are conducted; cutting forces, effective cutting powers, and tool wear are measured. The parametric influences of cutting speed, feed rate, and process conditions on the cutting performances such as resultant cutting force, specific effective cutting power, and flank wear are analyzed and proper conclusions are drawn. Nature-inspired metaheuristic bat algorithm is employed to handle the multiobjective optimization of the conflicting performances. Finally, the optimum cutting condition for each process condition can be selected from calculated Pareto optimal fronts by the user according to the planning requirements. Rastee D. Koyee, Uwe Heisel, Siegfried Schmauder, and Rocco Eisseler Copyright © 2014 Rastee D. Koyee et al. All rights reserved. Cutting Forces in Milling of Carbon Fibre Reinforced Plastics Thu, 13 Nov 2014 13:55:11 +0000 http://www.hindawi.com/journals/ijme/2014/439634/ The machining of fibre reinforced composites is an important activity for optimal application of these advanced materials into engineering fields. During machining any excessive cutting forces have to be avoided in order to prevent any waste product in the last stages of production cycle. Therefore, the ability to predict the cutting forces is essential to select process parameters necessary for an optimal machining. In this paper the effect of cutting conditions during milling machining on cutting force and surface roughness has been investigated. In particular the cutting force components have been analysed in function of the principal process parameters and of the contact angle. This work proposes experimental models for the determination of cutting force components for CFRP milling. Luca Sorrentino and Sandro Turchetta Copyright © 2014 Luca Sorrentino and Sandro Turchetta. All rights reserved. Flexural Strength Analysis of Starch Based Biodegradable Composite Using Areca Frond Fibre Reinforcement Thu, 13 Nov 2014 09:43:22 +0000 http://www.hindawi.com/journals/ijme/2014/769012/ Natural fibres and biodegradable matrices are being considered nowadays as substitutes to synthetic fibre reinforced polymer composites mainly in sectors where high load carrying capacity and high strength are not prerequisites. Present study utilizes biodegradable matrix composite prepared by varying the weight of the base material (95–170 g), binder (5–10 g), and plasticizer (5–20 g) with treated areca frond fibres as reinforcement. Contents are transferred to a pneumatic press, compacted, and subjected to curing. Taguchi method with L8 orthogonal array was used to reduce the number of experiments. Specimens for the flexural tests are cut out from the prepared laminates and tests are performed using UTM. Maximum flexural strength of 16.97 MPa was obtained with a combination of base (170 g), binder (10 g), and plasticizer (5 g). Analysis of the results indicated that plasticizer has the maximum effect on flexural strength of the biodegradable composites. Srinivas Shenoy Heckadka, Manjeshwar Vijaya Kini, Raghuvir Pai Ballambat, Satish Shenoy Beloor, Sathish Rao Udupi, and Ullal Achutha Kini Copyright © 2014 Srinivas Shenoy Heckadka et al. All rights reserved. Characterization and Optimization of Mechanical Properties of ABS Parts Manufactured by the Fused Deposition Modelling Process Mon, 10 Nov 2014 12:07:57 +0000 http://www.hindawi.com/journals/ijme/2014/598531/ While fused deposition modelling (FDM) is one of the most used additive manufacturing (AM) techniques today due to its ability to manufacture very complex geometries, the major research issues have been to balance ability to produce aesthetically appealing looking products with functionality. In this study, five important process parameters such as layer thickness, part orientation, raster angle, raster width, and air gap have been considered to study their effects on tensile strength of test specimen, using design of experiment (DOE). Using group method of data handling (GMDH), mathematical models relating the response with the process parameters have been developed. Using differential evolution (DE), optimal process parameters have been found to achieve good strength simultaneously for the response. The optimization of the mathematical model realized results in maximized tensile strength. Consequently, the additive manufacturing part produced is improved by optimizing the process parameters. The predicted models obtained show good correlation with the measured values and can be used to generalize prediction for process conditions outside the current study. Results obtained are very promising and hence the approach presented in this paper has practical applications for design and manufacture of parts using additive manufacturing technologies. Godfrey C. Onwubolu and Farzad Rayegani Copyright © 2014 Godfrey C. Onwubolu and Farzad Rayegani. All rights reserved. Failure Prediction in Bulk Metal Forming Process Mon, 10 Nov 2014 11:35:08 +0000 http://www.hindawi.com/journals/ijme/2014/385065/ An important concern in metal forming is whether the desired deformation can be accomplished without defects in the final product. Various ductile fracture criteria have been developed and experimentally verified for a limited number of cases of metal forming processes. These criteria are highly dependent on the geometry of the workpiece and cannot be utilized for complicated shapes without experimental verification. However, experimental work is a resource hungry process. This paper proposes the ability of finite element analysis (FEA) software such as LS-DYNA to pinpoint the crack-like flaws in bulk metal forming products. Two different approaches named as arbitrary Lagrangian-Eulerian (ALE) and smooth particle hydrodynamics (SPH) formulations were adopted. The results of the simulations agree well with the experimental work and a comparison between the two formulations has been carried out. Both approximation methods successfully predicted the flow of workpiece material (plastic deformation). However ALE method was able to pinpoint the location of the flaws. Ameen Topa and Qasim H. Shah Copyright © 2014 Ameen Topa and Qasim H. Shah. All rights reserved. Resistance Spot Welding Optimization Based on Artificial Neural Network Sun, 09 Nov 2014 12:11:05 +0000 http://www.hindawi.com/journals/ijme/2014/154784/ Resistance Spot Welding (RSW) is processed by using aluminum alloy used in the automotive industry. The difficulty of RSW parameter setting leads to inconsistent quality between welds. The important RSW parameters are the welding current, electrode force, and welding time. An additional RSW parameter, that is, the electrical resistance of the aluminum alloy, which varies depending on the thickness of the material, is considered to be a necessary parameter. The parameters applied to the RSW process, with aluminum alloy, are sensitive to exact measurement. Parameter prediction by the use of an artificial neural network (ANN) as a tool in finding the parameter optimization was investigated. The ANN was designed and tested for predictive weld quality by using the input and output data in parameters and tensile shear strength of the aluminum alloy, respectively. The results of the tensile shear strength testing and the estimated parameter optimization are applied to the RSW process. The achieved results of the tensile shear strength output were mean squared error (MSE) and accuracy equal to 0.054 and 95%, respectively. This indicates that that the application of the ANN in welding machine control is highly successful in setting the welding parameters. Thongchai Arunchai, Kawin Sonthipermpoon, Phisut Apichayakul, and Kreangsak Tamee Copyright © 2014 Thongchai Arunchai et al. All rights reserved. Comparison of Microstructure and Mechanical Properties of A356/SiC Metal Matrix Composites Produced by Two Different Melting Routes Tue, 21 Oct 2014 05:58:46 +0000 http://www.hindawi.com/journals/ijme/2014/747865/ A356/SiC metal matrix composites with different weight percent of SiC particles were fabricated by two different techniques such as mechanical stir casting and electromagnetic stir casting. The results of macrostructure, microstructure, and XRD study revealed uniform distribution, grain refinement, and low porosity in electromagnetic stir casing samples. The mechanical results showed that the addition of SiC particles led to the improvement in tensile strength, hardness, toughness, and fatigue life. It indicates that type of fabrication process and percentage of reinforcement are the effective factors influencing the mechanical properties. It is observed that when percentage of reinforcement increases in electromagnetic stir casting, best mechanical properties are obtained. Shashi Prakash Dwivedi, Satpal Sharma, and Raghvendra Kumar Mishra Copyright © 2014 Shashi Prakash Dwivedi et al. All rights reserved. Modeling of Tool Wear in Vibration Assisted Nano Impact-Machining by Loose Abrasives Mon, 20 Oct 2014 00:00:00 +0000 http://www.hindawi.com/journals/ijme/2014/291564/ Vibration assisted nano impact-machining by loose abrasives (VANILA) is a novel nanomachining process that combines the principles of vibration assisted abrasive machining and tip-based nanomachining, to perform target specific nanoabrasive machining of hard and brittle materials. An atomic force microscope (AFM) is used as a platform in this process wherein nanoabrasives, injected in slurry between the workpiece and the vibrating AFM probe which is the tool, impact the workpiece and cause nanoscale material removal. The VANILA process are conducted such that the tool tip does not directly contact the workpiece. The level of precision and quality of the machined features in a nanomachining process is contingent on the tool wear which is inevitable. Initial experimental studies have demonstrated reduced tool wear in the VANILA process as compared to indentation process in which the tool directly contacts the workpiece surface. In this study, the tool wear rate during the VANILA process is analytically modeled considering impacts of abrasive grains on the tool tip surface. Experiments are conducted using several tools in order to validate the predictions of the theoretical model. It is seen that the model is capable of accurately predicting the tool wear rate within 10% deviation. Sagil James and Murali M. Sundaram Copyright © 2014 Sagil James and Murali M. Sundaram. All rights reserved. Material Removal Rate, Electrode Wear Rate, and Surface Roughness Evaluation in Die Sinking EDM with Hollow Tool through Response Surface Methodology Tue, 23 Sep 2014 05:25:52 +0000 http://www.hindawi.com/journals/ijme/2014/259129/ Electrical discharge machining is one of the earliest nontraditional machining, extensively used in industry for processing of parts having unusual profiles with reasonable precision. In the present work, an attempt has been made to model material removal rate, electrode wear rate, and surface roughness through response surface methodology in a die sinking EDM process. The optimization was performed in two steps using one factor at a time for preliminary evaluation and a Box-Behnken design involving three variables with three levels for determination of the critical experimental conditions. Pulse on time, pulse off time, and peak current were changed during the tests, while a copper electrode having tubular cross section was employed to machine through holes on EN 353 steel alloy workpiece. The results of analysis of variance indicated that the proposed mathematical models obtained can adequately describe the performances within the limits of factors being studied. The experimental and predicted values were in a good agreement. Surface topography is revealed with the help of scanning electron microscope micrographs. Teepu Sultan, Anish Kumar, and Rahul Dev Gupta Copyright © 2014 Teepu Sultan et al. All rights reserved. Finite Element Analysis of PMMA Stretch Blow Molding Wed, 27 Aug 2014 07:18:42 +0000 http://www.hindawi.com/journals/ijme/2014/175743/ The electric bubbles are a useful product made of PMMA material. They are produced by the stretch blow molding process. Thickness, which reflects the quality of the electric bubble, is a crucial parameter that deserves special attention for the molding process. In this work, finite element simulations of the stretch blow molding process are performed aiming at the determination of the preform geometry to ensure homogeneous thickness of the finished product. The geometrical parameters of the preform are optimized allowing a better homogeneity thickness compared to existing data. The predicted parameters allow the improvement of the thickness distribution. The standard deviation of the thickness is reduced to about 95% compared to the existing bubble. Afef Bougharriou, Mohieddine Jeridi, Mohamed Hdiji, Anoir Boughrira, and Kacem Saï Copyright © 2014 Afef Bougharriou et al. All rights reserved. Design and Fabrication of Diffractive Light-Collecting Microoptical Device with 1D and 2D Lamellar Grating Structures Thu, 05 Jun 2014 12:37:55 +0000 http://www.hindawi.com/journals/ijme/2014/101823/ This paper presents the optimal design method of diffractive light-collecting microoptical device and its fabrication method by E-beam lithography, fast atom beam etching, and hot-embossing processes. The light-collecting device proposed in the paper is comprised of 9 (3 × 3) blocks of optical elements: 4 blocks of 1D lamellar grating structures, 4 blocks of 2D lamellar grating structures, and a single block of nonpatterned element at the center, which acts for lens to be able to collect the diffracted and transmitted lights from the lamellar grating structures into the focus area. The overall size of the light-collecting device is 300 × 300 μm2, and the size of each block was practically designed as 100 × 100 μm2. The performance of 1D and 2D lamellar grating structures was characterized in terms of diffraction efficiency and diffraction angle using a rigorous coupled-wave analysis (RCWA) method, and those geometric parameters, depth, pitch, and orientation, were optimized to achieve a high light-collecting efficiency. The master molds for the optimized structures were fabricated on Si substrate by E-beam lithography and fast atom beam etching processes. The 100 μm thick patterned polymethyl methacrylate (PMMA) film was then replicated by a hot-embossing process. As a result, the patterned PMMA film collected 63.0% more incident light than a nonpatterned one. ChaBum Lee Copyright © 2014 ChaBum Lee. All rights reserved. Enhancing Multistage Deep-Drawing and Ironing Manufacturing Processes of Axisymmetric Components: Analysis and Experimentation Thu, 29 May 2014 07:49:09 +0000 http://www.hindawi.com/journals/ijme/2014/596128/ An optimization technique for combined processes of deep-drawing and ironing has been created in order to improve the total process time and cost in manufacturing procedures of axisymmetric components. The initial solution is optimized by means of an algorithm that minimizes the total time of the global process, based on relationship between lengths, diameters, and velocities of each stage of a multistage process and subject to constraints related to the drawing ratio. The enhanced solution offers a significant reduction in time and cost of the global process. The final results, applied to three cases, are compared with experimental results, showing the accuracy of the complete solution. F. Javier Ramírez, Rosario Domingo, Michael S. Packianather, and Miguel A. Sebastian Copyright © 2014 F. Javier Ramírez et al. All rights reserved. Analyzing the Effectiveness of Microlubrication Using a Vegetable Oil-Based Metal Working Fluid during End Milling AISI 1018 Steel Tue, 15 Apr 2014 09:19:54 +0000 http://www.hindawi.com/journals/ijme/2014/261349/ Microlubrication minimizes the exposure of metal working fluids to the machining operators leading to an economical, safer, and healthier workplace environment. In this study, a vegetable oil-based lubricant was used to conduct wear analysis and to analyze the effectiveness of microlubrication during end milling AISI 1018 steel. A solid carbide cutting tool with bright oxide finish was used with varying cutting speed and feed rate having a constant depth of cut. Abrasion was the dominant wear mechanism for all the cutting tools under consideration. Other than abrasion, sliding adhesive wear of the workpiece materials was also observed. The scanning electron microscope investigation of the used cutting tools revealed microfatigue cracks, welded microchips, and unusual built-up edges on the cutting tools flank and rake side. A full factorial experiment was conducted and regression models were generated for both the sides of tool flank wear. The study shows that with a proper selection of the cutting parameters it is possible to obtain higher tool life. Vasim Shaikh, Nourredine Boubekri, and Thomas W. Scharf Copyright © 2014 Vasim Shaikh et al. All rights reserved. Observation of Drilling Burr and Finding out the Condition for Minimum Burr Formation Mon, 24 Mar 2014 13:58:58 +0000 http://www.hindawi.com/journals/ijme/2014/208293/ Suppression or elimination of burr formation at the exit edge of the workpiece during drilling is essential to make quality products. In this work, low alloy steel specimens have been drilled to observe burr height under different machining conditions. Taper shank, uncoated 14 mm diameter HSS twist drills are used in these experiments. Dry environment is maintained in experiment set I. Water is applied as cutting fluid in experiment set II. In the next four sets of experiments, the effect of providing back-up support material and exit edge bevel is observed on formation of burr at the exit edge of specimens under dry and wet conditions. It is revealed that an exit edge bevel of 31 degrees with water as the cutting fluid gives negligible burr at the exit edge of the drilled hole at certain machining conditions. Use of a back-up support can also reduce drill burr to a large extent. In this paper, artificial neural networks (ANN) are developed for modeling experimental results, and modeled values show close matching with the experimental results with small deviations. Nripen Mondal, Biswajit Sing Sardar, Ranendra Nath Halder, and Santanu Das Copyright © 2014 Nripen Mondal et al. All rights reserved. Optimization of Fusion Zone Grain Size, Hardness, and Ultimate Tensile Strength of Pulsed Current Microplasma Arc Welded AISI 304L Sheets Using Genetic Algorithm Wed, 05 Mar 2014 09:36:07 +0000 http://www.hindawi.com/journals/ijme/2014/943643/ Austenitic stainless steel sheets have gathered wide acceptance in the fabrication of components, which require high temperature resistance and corrosion resistance, such as metal bellows used in expansion joints in aircraft, aerospace, and petroleum industry. In case of single pass welding of thinner sections of this alloy, Pulsed Current Microplasma Arc Welding (PCMPAW) was found beneficial due to its advantages over the conventional continuous current process. The quality of welded joint depends on the grain size, hardness, and ultimate tensile strength, which have to be properly controlled and optimized to ensure better economy and desirable mechanical characteristics of the weld. This paper highlights the development of empirical mathematical equations using multiple regression analysis, correlating various process parameters to grain size, and ultimate tensile strength in PCMPAW of AISI 304L sheets. The experiments were conducted based on a five-factor, five-level central composite rotatable design matrix. A genetic algorithm (GA) was developed to optimize the process parameters for achieving the desired grain size, hardness, and ultimate tensile strength. Siva Prasad Kondapalli, Srinivasa Rao Chalamalasetti, and Nageswara Rao Damera Copyright © 2014 Siva Prasad Kondapalli et al. All rights reserved. Knowledge Management for Topological Optimization Integration in Additive Manufacturing Mon, 17 Feb 2014 12:22:10 +0000 http://www.hindawi.com/journals/ijme/2014/356256/ Engineering design optimization of mechanical structures is nowadays essential in the mechanical industry (automotive, aeronautics, etc.). To remain competitive in the globalized world, it is necessary to create and design structures that, in addition to complying specific mechanical performance, should be less expensive. Engineers must then design parts or assemblies that are a better compromise between mechanical and functional performance, weight, manufacturing costs, and so forth. In this context Additive Manufacturing (AM) process offers the possibility to avoid tools and manufacture directly the part. There are numerous technologies which are using different kind of material. For each of these, there are at least two materials: the production material and the support one. Support material is, in most cases, cleaned and becomes a manufacturing residue. Improving the material volume and the global mass of the product is an essential aim surrounding the integration of simulation in additive manufacturing process. Moreover, the layer-by-layer technology of additive manufacturing allows the design of innovative objects, and the use of topological optimization in this context can create a very interesting combination. The purpose of our paper is to present the knowledge management of an AM trade oriented tool which integrated the topological optimization of parts and internal patterns. Nicolas Gardan Copyright © 2014 Nicolas Gardan. All rights reserved. Mechanistic Force Modeling for Broaching Process Mon, 17 Feb 2014 12:17:12 +0000 http://www.hindawi.com/journals/ijme/2014/485712/ There is a demand for mechanistic force model that can predict and simulate the broaching process. In this paper, an attempt has been made for mechanistic force modeling of the broaching operation and experimental corroboration with the simulated result. The stiffness and damping coefficients for dynamic model are computed from the natural frequency of the broaching system and actual damped natural frequency has been obtained experimentally. Experimental work has been carried to compute the dynamic model parameters such as mass, stiffness, and damping coefficients. The simulated dynamic forces are illustrated graphically and are closely in agreement with the results obtained through manual broaching process. Raghavendra Kamath Cholpadi and Appu Kuttan Copyright © 2014 Raghavendra Kamath Cholpadi and Appu Kuttan. All rights reserved. Optimized Injection Molding of Unfilled and Glass Filled PA6 Gears Mon, 10 Feb 2014 09:46:22 +0000 http://www.hindawi.com/journals/ijme/2014/719462/ Shrinkage behavior is a crucial problem in manufacturing plastic molded gear. This is because it negatively affects the dimensional stability and accuracy of the involute profile, as well as the concentricity, roundness, tooth spacing uniformity, and size of the gear. By integrating the Taguchi robust design, Grey relational analysis, and principal component analysis, we investigated the dimensional stability related to the shrinkage of tooth thickness, addendum circle, and dedendum circle of molded gear via the optimization of processing parameters and glass fiber reinforcement. The results revealed that the optimal combination of the processing parameters of the molded gear to achieve minimum shrinkage is melt temperature of 260°C, packing pressure of 60%, packing time of 5 s, and cooling time of 30 s. The melt temperature showed the highest comparability sequence among the four key process parameters examined, followed by packing pressure, cooling time, and packing time. Meanwhile, the presence of glass fibers induced higher deviations of tooth thickness, addendum circle, and dedendum circle than those of the unfilled polyamide 6 gears. Nik Mizamzul Mehat, Shahrul Kamaruddin, and Abdul Rahim Othman Copyright © 2014 Nik Mizamzul Mehat et al. All rights reserved. Relevance Vector Machine Based Analyses of MRR and SR of Electrodischarge Machining Designed by Response Surface Methodology Sat, 28 Dec 2013 07:47:51 +0000 http://www.hindawi.com/journals/ijme/2013/170746/ Relevance vector machine is found to be one of the best predictive models in the area of pattern recognition and machine learning. The important performance parameters such as the material removal rate (MRR) and surface roughness (SR) are influenced by various machining parameters, namely, discharge current (), pulse on time (), and duty cycle (tau) in the electrodischarge machining process (EDM). In this communication, the MRR and SR of EN19 tool steel have been predicted using RVM model and the analysis of variance (ANOVA) results were performed by implementing response surface methodology (RSM). The number of input parameters used for the RVM model is discharge current (), pulse on time (), and duty cycle (tau). At the output, the corresponding model predicts both MRR and SR. The performance of the model is determined by regression test error which can be obtained by comparing both predicted MRR and SR from model and experimental data is designed using central composite design (CCD) based RSM. Our result shows that the regression error is minimized by using cubic kernel function based RVM model and the discharge current is found to be one of the most significant machining parameters for MRR and SR from ANOVA. Kanhu Charan Nayak, Rajesh Kumar Tripathy, and Sudha Rani Panda Copyright © 2013 Kanhu Charan Nayak et al. All rights reserved. Developing a STEP-Compliant Multiagent on an Interoperable and Integrated CAD/CAM Platform Tue, 24 Dec 2013 16:29:57 +0000 http://www.hindawi.com/journals/ijme/2013/974759/ Practical implementation of a STEP-based architecture to provide a fully integrated and interoperable platform of data exchange has always been an intriguing issue. A variety of CAD/CAM environments are struggling to embed and support STEP standard and its protocols in order to seamlessly operate within global data exchange. However, apparent paucity of efficient and reliable structure for data communication, manipulation, and restoration has remarkably hindered the desired progress. In this paper, taking these shortcomings into account, a practical architecture is introduced and STEP-based agents are implemented and installed on the platform. Moreover, feature recognition, interaction, and machining precedence as crucial issues of CAD/CAM research have been considered in developing the interoperable platform. Seamless integration and interaction of CAD/CAM modules are provided in the proposed system. The prototype is finally verified and discussed through a case study. Alireza Mokhtar and Omid Fatahi Valilai Copyright © 2013 Alireza Mokhtar and Omid Fatahi Valilai. All rights reserved. Improving the Performance of Reprocessed ABS Products from the Manufacturing Perspective via the Taguchi Method Mon, 23 Dec 2013 10:24:27 +0000 http://www.hindawi.com/journals/ijme/2013/824562/ Additives are costly and can have negative environmental effects. Thus, searching for other alternatives to improve recycling plastics without using additives is necessary. This study aims to improve the hoop tensile strength, elongation at break, and shrinkage of the ring stopper made from an acrylonitrile butadiene styrene blend comprising 40% recyclates through the optimization of processing parameters using the Taguchi method. By adopting the Taguchi orthogonal array, four controllable factors each at three levels are tested to determine the optimal combination of factors and levels in the injection moulding process. Considering the multiple quality characteristics involved in this study, we investigate the effects of processing parameters on hoop tensile strength, elongation at break, and shrinkage of the ring stopper both separately and simultaneously because changing a parameter can result in the improvement or deterioration of each quality response and of the overall product performance. The results revealed that the performance of an injection-moulded ring stopper under the optimal process conditions is equivalent or slightly better than that of the part produced from virgin resin. The performance of recycled plastics can be effectively enhanced to levels comparable with virgin resins using the Taguchi optimization approach. Ng Chin Fei, Nik Mizamzul Mehat, Shahrul Kamaruddin, and Zulkifli Mohamad Ariff Copyright © 2013 Ng Chin Fei et al. All rights reserved. Assessing the Performance of Two Bioinspired Algorithms to Solve Single-Row Layout Problem Thu, 19 Dec 2013 14:40:56 +0000 http://www.hindawi.com/journals/ijme/2013/265904/ The single-row layout problem (SRLP), also known as the one-dimensional layout problem, deals with arranging a number of rectangular machines/departments with equal or varying dimensions on a straight line. Since the problem is proved to be NP-hard, there are several heuristics developed to solve the problem. This study introduces both a Clonal Selection Algorithm (CSA) and a Bacterial Foraging Algorithm (BFA) for SRLP. The performance of the algorithms is assessed by using three (small, medium, and large sized) well known test problems available in the literature. The promising results illustrated that both algorithms had generated the best known solutions so far for most of the problems or provided better results for a number of problems. Berna Haktanirlar Ulutas Copyright © 2013 Berna Haktanirlar Ulutas. All rights reserved. Optimal Designing of Variables Chain Sampling Plan by Minimizing the Average Sample Number Tue, 17 Dec 2013 15:37:52 +0000 http://www.hindawi.com/journals/ijme/2013/751807/ We investigate the optimal designing of chain sampling plan for the application of normally distributed quality characteristics. The chain sampling plan is one of the conditional sampling procedures and this plan under variables inspection will be useful when testing is costly and destructive. The advantages of this proposed variables plan over variables single sampling plan and variables double sampling plan are discussed. Tables are also constructed for the selection of optimal parameters of known and unknown standard deviation variables chain sampling plan for specified two points on the operating characteristic curve, namely, the acceptable quality level and the limiting quality level, along with the producer’s and consumer’s risks. The optimization problem is formulated as a nonlinear programming where the objective function to be minimized is the average sample number and the constraints are related to lot acceptance probabilities at acceptable quality level and limiting quality level under the operating characteristic curve. S. Balamurali and M. Usha Copyright © 2013 S. Balamurali and M. Usha. All rights reserved. Integrated Inventory Model for Deteriorating Items with Price-Dependent Demand under Quantity-Dependent Trade Credit Tue, 10 Dec 2013 09:16:42 +0000 http://www.hindawi.com/journals/ijme/2013/439190/ This paper explores an integrated inventory model when the deterioration rate follows exponential distribution under trade credit. Here, it is assumed that demand rate is a function of selling price and the permissible delay in payment depends on the order quantity. In the model shortages are completely backlogged. The maximization of the total profit per unit of time is taken as the objective function to study the retailer’s optimal ordering policy. This paper also presents a practical application example where the proposed inventory model is utilized to support business decision making. Particularly, the model developed in the paper could be useful in the area of supply chain management. Finally, sensitivity analysis of the optimal solution with respect to major parameters is carried out. Our result illustrates that this model can be quite useful in determining the optimal ordering policy when the trade credit period is being analyzed. Karuppuchamy Annadurai Copyright © 2013 Karuppuchamy Annadurai. All rights reserved. A Branch and Bound Approach to Solve the Preemptive Resource Leveling Problem Sun, 27 Oct 2013 14:41:53 +0000 http://www.hindawi.com/journals/ijme/2013/930920/ We study resource constrained project scheduling problem with respect to resource leveling as objective function and allowance of preemption in activities. The branch and bound algorithms proposed in previous researches on resource leveling problem do not consider preemption. So, representing a model for the problem, a branch and bound algorithm is proposed. This algorithm can handle preemption in resource leveling problem. Comparing the resource leveling problem and the preemptive resource leveling problem, it is observed that considering preemption in the problem leads to better results in the objective function. This improvement imposes additional time to solve the problem. Coding the algorithm in MATLAB and checking it on the projects with 8 and 10 activities, results show that the proposed algorithm is efficient. Behrouz Afshar-Nadjafi, Zeinab Khalaj, and Esmaeil Mehdizadeh Copyright © 2013 Behrouz Afshar-Nadjafi et al. All rights reserved. Uniform Dispersion of Multiwalled Carbon Nanotubes in Copper Matrix Nanocomposites Using Metal Injection Molding Technique Wed, 02 Oct 2013 10:03:46 +0000 http://www.hindawi.com/journals/ijme/2013/386141/ This work presents a novel fabrication approach of multiwalled carbon nanotubes (MWNTs) reinforced copper (Cu) matrix nanocomposites. A combination of nanoscale dispersion of functionalized MWNTs in low viscose media of dissolved paraffin wax under sonication treatment followed by metal injection molding (MIM) technique was adopted. MWNTs contents were varied from 0 to 10 vol.%. Information about the degree of purification and functionalization processes, evidences on the existence of the functional groups, effect of sonication time on the treated MWNTs, and microstructural analysis of the fabricated Cu/MWNTs nanocomposites were determined using TEM, EDX, FESEM, and Raman spectroscopy analysis. The results showed that the impurities of the pristine MWNTs such as Fe, Ni catalyst, and the amorphous carbon have been significantly removed after purification process. Meanwhile, FESEM and TEM observations showed high stability of MWNTs at elevated temperatures and uniform dispersion of MWNTs in Cu matrix at different volume fractions and sintering temperatures (950, 1000 & 1050°C). The experimentally measured thermal conductivities of Cu/MWNTs nanocomposites showed remarkable increase (11.25% higher than sintered pure Cu) with addition of 1 vol.% MWNTs, and slight decrease below the value of sintered Cu at 5 and 10 vol.% MWNTs. Ali Samer Muhsan, Faiz Ahmad, Norani M. Mohamed, Puteri Sri Melor Megat Yusoff, and Muhammad Rafi Raza Copyright © 2013 Ali Samer Muhsan et al. All rights reserved. Fuzzy Logic-Based Techniques for Modeling the Correlation between the Weld Bead Dimension and the Process Parameters in MIG Welding Mon, 30 Sep 2013 15:51:07 +0000 http://www.hindawi.com/journals/ijme/2013/230463/ Fuzzy logic-based techniques have been developed to model input-output relationships of metal inert gas (MIG) welding process. Both conventional and hierarchical fuzzy logic controllers (FLCs) of Mamdani type have been developed, and their performances are compared. The conventional FLC suffers from the curse of dimensionality for handling a large number of variables, and a hierarchical FLC was proposed earlier to tackle this problem. However, in that study, both the structure and knowledge base of the FLC were not optimized simultaneously, which has been attempted here. Simultaneous optimization of the structure and knowledge base is a difficult task, and to solve it, a genetic algorithm (GA) will have to deal with the strings having varied lengths. A new scheme has been proposed here to tackle the problem related to crossover of two parents with unequal lengths. It is interesting to observe that the conventional FLC yields the best accuracy in predictions, whereas the hierarchical FLC can be computationally faster than others but at the cost of accuracy. Moreover, there is no improvement of interpretability by introducing a hierarchical fuzzy system. Thus, there exists a trade-off between the accuracy obtained in predictions and computational complexity of various FLCs. Y. Surender and Dilip Kumar Pratihar Copyright © 2013 Y. Surender and Dilip Kumar Pratihar. All rights reserved.