bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Bi-Level Mathematical Programming and Heuristics for the Cellular Manufacturing Facility Layout Problem
Authors: Allahyari Maral Zafar , Azab Ahmed
Published: September 2015

A good layout plan results in improvements in machine utilization, setup time, and reduction in work-in-process inventory and material handling cost. Facility layout problem (FLP) for CMS includes both intercellular- and intracellular-layout. Most of the literature takes a discrete approach and rarely considers operations sequence and part demand. In this paper, a novel bi-level heuristic and mixed-integer non-linear programming continuous model for the layout design of cellular manufacturing are developed. Machine tools and manufacturing cells layout are determined sequentially by solving a leader and follower problem, respectively. Facilities are assumed unequal sizes. Both overlap elimination and aisle constraint modeling have been considered. The model is nonlinear; problem is NP-hard. Hence, only small instances of the problem can be solved using the exact linearized model. The developed heuristic is used to solve large instances of the problem. A real case study from the metal cutting inserts industry, where multiple families of inserts have been formed, each with its distinguished master plan, is presented.
Service-Oriented Predictive Maintenance for Large Scale Machines Based on Perception Big Data
Authors: Yao Bitao , Zhou Zude , Xu Wenjun , Fang Yilin , Shao Luyang , Wang Qiang , Liu Aiming
Published: September 2015

Large scale machines (LSMs) are always crucial equipments in manufacturing. Maintaining reliability, precision and safety for LSMs is very important. However, LSMs always work under extreme condition and are prone to degradation or failure. Therefore, maintenance is important for them. Compared with preventive maintenance, predictive maintenance is cost-saving. Besides, predictive maintenance is a more sustainable way by reducing failure and enhancing safety. Condition perception is needed in predictive maintenance. Due to the complex structure and large scale of LSMs, the perception data can be characterized as Big Data. Therefore, the storage and processing of Big Data needs to be integrated into maintenance. Considering that LSMs can be distributed all over the word, cloud service can be a proper way to support maintenance in a global environment. In this paper, a framework of service-oriented predictive maintenance for LSMs based on perception Big Data is synthesized to meet those demands. The methodologies are discussed as well. Finally, an industry case is studied to illustrate the implementing of predictive maintenance.
Process Simulation of Electrochemical Machining of Convexity Structure on Revolving Workpiece
Authors: Zhu Zengwei , Wang Dengyong , Bao Jun , Zhu Di
Published: September 2015

A special electrochemical machining (ECM) process using a revolving cathode tool with hollow windows is presented. Unlike conventional sinking ECM, this presented ECM process fabricates the convexity structures on a revolving part by the relative rotation of anode workpiece and cathode tool. In this paper, a mathematical model is established to describe the evolution of the machining process, the finite element simulations of the new forming fashion are focused for the workpiece’s revolving surface and the convexity’s side profile. The simulation results show that both the cathode feed rate and the applied voltage have significant influence on the equilibrium inter-electrode gap and the material removal rate. The side profile of the convexity is related to radius of the cathode tool. It is expected that the equilibrium gap and steady removal rate could be achieved by optimizing the cathode feed rate and the voltage, the required side profile taper of the convexity could be obtained by selecting the proper tool radius.
A Conceptual Framework for Effective Implementation of Integrated Manufacturing Practices
Authors: Wakchaure V. D. , Nandurkar K. N. , Kallurkar S. P. , Gadalla M. A.
Published: September 2015

Literature on manufacturing performance improvement has focused on various combinations of joint implementation of JIT, TQM, TPM, SCM and ERP in order to achieve multiple capabilities. Most of the literature is either conceptual or empirical and motivated to show how joint implementation is capable of delivering higher level of performance as compared to individual implementation. But, process-based literature dealing with implementation issues is scarce and investigating the order of implementing best practices remains an important research question. This paper provides generic stepwise implementation framework to attain highest level of manufacturing capability demonstrated by full scale JIT implementation. The synergies among integrated manufacturing practices of JIT, TQM, TPM, SCM and ERP have been used while developing ‘weeble’ shaped implementation framework. The modified ‘TPS House’ is also presented which incorporates the activities necessary to create the foundation for JIT implementation. The case study of automobile component manufacturer illustrates the journey of practice implementation to achieve manufacturing competitiveness.
The Assembly Variation Modeling for the Rear Casing Wax Part Based on Polar Coordinate
Authors: Liu Changhui , Jin Sun , Lai Xinmin , Luo Jie , He Bo , Li Fei
Published: September 2015

Rear casing is a key part of the aeroplane engine. Its dimensional precision is significant to the quality of the aeroplane engine. In the rear casing manufacturing process, the assembly variation of its corresponding wax dramatically affects the final dimensions. In this paper, a polar-coordinate based model is proposed to calculate the assembly variation of ring-shaped rear casing wax part. It avoids the variation caused by the coupling relationship between Cartesian coordinate systems and locating position. We also compare the polar-coordinate based model with the ordinary one in practical application. The results show that the polar-coordinate based model can simplify the calculating process and improve the computational accuracy for the assembly variation analysis of the ring-shaped part.
Evaluation of the Impact of Process Modeling on Opportunity Loss/Gain in a Manufacturing Environment
Authors: Gadalla Mohamed A. , Seif Mohamed
Published: September 2015

Process modeling is a very common research area in the field of manufacturing engineering. Examples of process modeling in machining include cutting forces, tool wear, machine thermal growth. Very few research has been done to demonstrate the impact they could have to improve a competitive edge of a company. In this paper, a model based on Monto Carlo simulation has been developed to provide an assessment tool for the impact of a process modeling on the competitive edge in an industrial setting. The competiveness is assessed as an improvement in quality by decreasing the defect rate, or as an opportunity to reduce losses if the process model has been developed or used. Finally, a case study based on an error compensation schema to eliminate the cutting tool deflection errors when machining free form surfaces is used to demonstrate the use and the benefits of a proposed assessment model.
Research on Surface Formation Mechanism in Elliptical Ultrasonic Assisted Grinding (EUAG) of Monocrystal Sapphire Using Structure Function Fractal Method
Authors: Wang Qiuyan , Liang Zhiqiang , Wang Xibin , Zhao Wenxiang , Wu Yongbo , Jiao Li , Zhou Tianfeng
Published: September 2015

This study investigates surface formation characteristics in elliptical ultrasonic assisted grinding (EUAG) of monocrystal sapphire using structure function fractal method. During the EUAG process, the workpiece is imposed to ultrasonically vibrate in two directions, i.e., vertical and parallel to work-surface, by using an elliptical ultrasonic vibrator. To clarify the work-surface formation characteristics in EUAG of sapphire material, grinding experiments are carried out involving sapphire substrate. In experiments, work-surface roughness is measured, and the ground work-surface morphology is examined by scanning electron microscope (SEM) and its fractal dimension was calculated by structure function method. The fractal dimension of ground surface in EUAG is bigger than that in conventional grinding (CG), meaning that the ground surface in EUAG is more exquisite and better than that in CG. Therefore, the fractal analysis method has the potential to reveal the ground surface characteristics in EUAG of monocrystal sapphire.
Molecular Dynamic Simulation of Surface Amorphization of NiTi Under Dynamic Shock Peening
Authors: Ren Zhencheng , Ye Chang , Dong Yalin
Published: September 2015

Surface amorphization of NiTi has been achieved by ultra-high strain rate dynamic loading induced by ultrasonic nano-crystal surface modification (UNSM). The amorphous microstructure was characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). To better understand the physical mechanism of the amorphization process, molecular dynamics (MD) simulation has been implemented to simulate the shock loading process and the results are consistent with the experiment. Central-symmetry parameter (CSP) and radial distribution function (RDF) were used to characterize the microstructure evolution. The simulation result demonstrates that the deformation is first formed as “twining” structure and then transformed into amorphization. The simulation also shows that shock speeds affect the amorphization level on the surface, while the shock amplitude mainly affects the amorphization depth.
A Sensitivity Analysis Study on the Material Properties and Process Parameters for Selective Laser Melting of Inconel 625
Authors: Criales Luis E. , Arısoy Yiğit M. , Özel Tuğrul
Published: September 2015

A prediction of the 2-D temperature profile and melt pool geometry for Selective Laser Melting (SLM) of Inconel 625 metal powder with a numerically-based approach for solving the heat conduction-diffusion equation was established in this paper. A finite element method solution of the governing equation was developed. A review of the current efforts in numerical modeling for laser-based additive manufacturing is presented. Initially, two-dimensional (2-D) temperature profiles along the scanning (x-direction) and hatch direction (y-direction) are calculated for a moving laser heat source to understand the temperature rise due to heating during SLM. The effects of varying laser power, scanning speed and the powder material’s density are analyzed. Based on the predicted temperature distributions, melt pool geometry, i.e. the locations at which melting of the powder material occurs, is determined. The results are chiefly compared against the published literature on melt pool data. The main goal of this research is to develop a computational tool with which investigation of the importance of various laser, material, and process parameters on the built dimensional quality in laser-based additive manufacturing becomes not only possible but also practical and reproducible.
Cryogenic Cutting of AZ31B-O Mg Alloy for Improved Surface Integrity: Part I — Process Principles and Material Modeling
Authors: Shen Ninggang , Ding Hongtao
Published: September 2015

This is Part I of a two-part series numerical study which investigates the improvement of surface integrity of AZ31B-O magnesium (Mg) alloy by cryogenic cutting. A light-weighted material of Mg alloy has great potentials for a more extensive application in transportation/aerospace industries and other areas, such as biodegradable medical implants. However, undesired surface integrity, in terms of grain size, microhardness, residual stresses, limit the functional performance of products with components in these materials on strength, wear resistance, fatigue resistance, and corrosion resistance. In this paper, the principle of improved surface integrity by cryogenic cutting is firstly introduced based on a previous experimental study on cryogenic orthogonal cutting of AZ31B-O Mg alloy. To demonstrate the capability of cryogenic cutting on improvement for AZ31B-O Mg alloy components, the improved surface integrity is characterized in terms of better surface finish, ultrarefined grains, increased surface microhardness, and compressive residual stress. A physics-based constitutive material model of plasticity and grain refinement is developed based on both slip and twinning mechanisms for the AZ31B-O Mg alloy undergoing cryogenic cutting.
Cryogenic Cutting of AZ31B-O Mg Alloy for Improved Surface Integrity: Part II — Physics-Based Process Modeling of Surface Microstructural Alteration
Authors: Shen Ninggang , Ding Hongtao , Gao Jiaying
Published: September 2015

This is the Part II of a two-part series numerical study which investigates the improvement of surface integrity of AZ31B-O magnesium (Mg) alloy by cryogenic cutting. In Part I, material constitutive behavior and grain refinement mechanism of AZ31B-O Mg alloy under cryogenic cutting conditions were modeled based on both slip and twinning mechanisms. In this study, the material model is implemented in the two-pass cryogenic cutting finite element simulations using a commercial machining simulation software package of AdvantEdge 6.4. The microstructural evolution by nanocrystalline grain refinement and other improvement of the surface integrity of AZ31B-O Mg alloy after cryogenic cutting are simulated. With quantitative assessments, simulation results are further discussed in grain refinement, microhardness change, residual stress, and slip/twinning mechanism in the machined surface of Mg alloy by cryogenic cutting. The results show that the surface integrity of Mg components can be significantly improved by using cryogenic cooling and a larger tool edge radius.
Wear Mechanism Analysis of Coated Carbide Tools in High-Speed Milling of Ti-6Al-4V Alloy via Cross-Section Characterization of Worn Cutting Edge
Authors: Li Anhai , Zhao Jun , Lin Fenghua
Published: September 2015

Tool wear analysis is essential in high speed machining, especially in the intermittent cutting and milling processes. Analyses of tool wear mechanisms will be beneficial for proposing the suggestions in the tool design process how to enhance the tool material properties to improve the cutting performance and eventually tool life. Wear mechanisms of coated carbide tools in high-speed dry milling of Ti-6A1-4V were assessed by characterization of the cross-section of worn tool cutting edge utilizing scanning electron microscopy, and the element distribution of the worn tool surface was detected by using energy dispersive spectroscopy. Results show that flank wear, chipping and flaking of tool material on the rake face and/or at the nose of tools were the dominant failure modes. And synergistic interaction among coating delamination, erosion wear, adhesion, dissolution-diffusion wear, and thermal-mechanical fatigue wear were the main wear mechanisms analyzed from cross-sectional worn cutting edge. Erosion wear was identified in high speed milling of Titanium alloy and introduced into the wear mechanisms of metal cutting tools. The hydromechanics characteristic of the chips produced in high-speed machining should be responsible for erosion wear of cuttings tools.
Research on a Novel High-Speed Pulsating Turning Technology
Authors: He Yuanfeng , Zhang Wenwu
Published: September 2015

As one of the most important machining methods, common turning has been applied on vast machining fields. Parts in revolving shape can be easily machined using lathe machine. But severe cutting heat is often generated by the contact of tool and work-piece in the procedure of turning. High cutting heat not only affects tool life and processing quality but also leads to low cutting efficiency and high energy consumption.

As to the demands of processing work-piece in large scale like marine shaft, heavy lathe is utilized. Considering the inertia load and the stability of the whole machine, speed of spindle is limited and the cutting efficiency is limited thusly because cutting speed is determined by rotate speed of spindle with fixed tool.

A novel high-speed pulsating turning technology (HSPT) was proposed in this paper. The contact relation between tool and work-piece was modified to be pulsating instead of continuous in common methods. The advantages of HSPT include lower energy consumption, less cutting heat, higher cutting speed compared with common method. Features of energy consumption, contact duration of tools and work-piece, surface roughness, etc. was investigated through theoretical analysis and experiment study, which have verified the advanced performance of HSPT.
Atomized Dielectric Spray-Based Electric Discharge Machining (Spray-EDM) for Sustainable Manufacturing
Authors: Pattabhiraman Arvind , Marla Deepak , Kapoor Shiv G.
Published: September 2015

A novel method of using atomized dielectric spray in EDM to reduce the consumption of dielectric is developed in this study. The atomized dielectric droplets form a moving dielectric film up on impinging the work surface that penetrates the inter-electrode gap and acts as a single phase dielectric medium between the electrodes and also effectively removes the debris particles from the discharge zone. EDM experiments are performed using three different dielectric supply methods, viz., conventional wet-EDM (electrodes submerged in dielectric medium), dry-EDM and spray-EDM in order to compare the processes based on material removal, tool electrode wear and flushing of debris from the inter-electrode gap across a range of discharge energies. It is observed that spray-EDM produces higher material removal compared to the other two methods for all combinations of discharge parameters used in the study. The tool electrode wear using atomized dielectric is significantly better than dry-EDM and comparable to that observed in conventional wet-EDM. The percentage of debris particles deposited within a distance of 100 μm from the center of EDM crater is also significantly reduced using the atomized dielectric spray EDM technique.
A Network Model to Optimize Upstream and Midstream Biomass-to-Bioenergy Supply Chain Costs
Authors: Mirkouei Amin , Haapala Karl R.
Published: September 2015

Growing awareness and concern within society over the use of and reliance on fossil fuels has stimulated research efforts in identifying, developing, and selecting alternative energy sources and energy technologies. Bioenergy represents a promising replacement for conventional energy, due to reduced environmental impacts and broad applicability. Sustainable energy challenges, however, require innovative manufacturing technologies and practices to mitigate energy and material consumption. This research aims to facilitate sustainable production of bioenergy from forest biomass and to promote deployment of novel processing equipment (mobile bio-refinery units). The study integrates knowledge from the renewable energy production and supply chain management disciplines to evaluate economic targets of bioenergy production with use of qualitative and quantitative techniques. The decision support system method employs two phases: (1) classification of potential biomass harvesting sites via decision tree analysis and (2) optimization of the supply network through a mixed integer linear programming model that minimizes the costs of upstream and midstream supply chain segments. While mobile units are shown to reduce biomass-to-bioenergy supply chain costs, production and deployment of the units is limited due to undeveloped bioenergy supply chains and quality uncertainty. It is reiterated that future research must address process-related and systemic issues in pursuit of sustainable energy technology development.
Parameter Estimation Using Markov Chain Monte Carlo Method in Mechanistic Modeling of Tool Wear During Milling
Authors: Niaki Farbod Akhavan , Ulutan Durul , Mears Laine
Published: September 2015

Several models have been proposed to describe the relationship between cutting parameters and machining outputs such as cutting forces and tool wear. However, these models usually cannot be generalized, due to the inherent uncertainties that exist in the process. These uncertainties may originate from machining, workpiece material composition, and measurements. A stochastic approach can be utilized to compensate for the lack of certainty in machining, particularly for tool wear evolution. The Markov Chain Monte Carlo (MCMC) method is a powerful tool for addressing uncertainties in machining parameter estimation. The Hybrid Metropolis-Gibbs algorithm has been chosen in this work to estimate the unknown parameters in a mechanistic tool wear model for end milling of difficult-to-machine alloys. The results show a good potential of the Markov Chain Monte Carlo modeling in prediction of parameters in the presence of uncertainties.
Cutting Force and Friction Modelling in High Speed End-Milling
Authors: Ojolo Sunday J. , Agunsoye Olumuwiya , Adesina Oluwole , Sobamowo Gbeminiyi M.
Published: September 2015

Temperature field in metal cutting process is one of the most important phenomena in machining process. Temperature rise in machining directly or indirectly determines other cutting parameters such as tool life, tool wear, thermal deformation, surface quality and mechanics of chip formation. The variation in temperature of a cutting tool in end milling is more complicated than any other machining operation especially in high speed machining. It is therefore very important to investigate the temperature distribution on the cutting tool–work piece interface in end milling operation. The determination of the temperature field is carried out by the analysis of heat transfer in metal cutting zone. Most studies previously carried out on the temperature distribution model analysis were based on analytical model and with the used of conventional machining that is continuous cutting in nature. The limitations discovered in the models and validated experiments include the oversimplified assumptions which affect the accuracy of the models. In metal cutting process, thermo-mechanical coupling is required and to carry out any temperature field determination successfully, there is need to address the issue of various forces acting during cutting and the frictional effect on the tool-work piece interface. Most previous studies on the temperature field either neglected the effect of friction or assumed it to be constant. The friction model at the tool-work interface and tool-chip interface in metal cutting play a vital role in influencing the modelling process and the accuracy of predicted cutting forces, stress, and temperature distribution. In this work, mechanistic model was adopted to establish the cutting forces and also a new coefficient of friction was also established. This can be used to simulate the cutting process in order to enhance the machining quality especially surface finish and monitor the wear of tool.
Development and Characterization of Inconel-Based Mixtures for Metal Injection Molding Applications
Authors: Tourneroche Paul , Gelin Jean-Claude , Barrière Thierry , Sahli Mohamed
Published: September 2015

In this paper, the development of a new mixture, called feedstock, based on nickel super-alloys for Metal Injection Molding (MIM) is presented. This feedstock, which will be used to obtain metallic parts for the aeronautic industry, is a mixture of the appropriate, environmentally friendly polymers and metallic powders. Many scientific problems should be taken into account. For example, it requires tight control of the process to achieve the strict chemical and physical properties, because of the application in aeronautic industry. Another difficulty is the large dimension and functional requirement of manufactured components, which subject to the high mechanical and thermal constraints. Additionally, the use of a biodegradable polymer makes the process more delicate because of its thermo-physical properties.
Reinforcing Inconel 718 Superalloy by Nano-TiC Particles in Selective Laser Melting
Authors: Wang Yachao , Shi Jing , Wang Yun
Published: September 2015

Metal components produced by additive manufacturing processes usually have inferior properties and performances as compared with the counterparts by the traditional forming and machining processes. To close the gap, the metal matrix can be strengthened by adding reinforcement particles in additive manufacturing processes. This research presents the fabrication of nano-TiC reinforced Inconel 718 composites using selective laser melting (SLM). Tensile and wear performance tests are conducted to evaluate the mechanical properties of the formed composites. It is discovered that the composites exhibit improved mechanical properties in terms of ultimate tensile strength and yield stress. Compared with the pure Inconel 718 specimens by SLM, the ultimate tensile strength and yield stress of the reinforced Inconel 718 increase by 207 MPa and 204 MPa, respectively, with 0.5 wt.% addition of nano-TiC particle. Smaller increases are observed with 0.25 wt.% and 1.0 wt.% nano-TiC additions. On the other hand, the addition of nano-TiC particles decreases the ductility of Inconel 718. To investigate the strengthening mechanism of nano reinforcement particles in SLM, the microstructures with different levels of nano-TiC particles are observed. The results indicate that the microstructure of Inconel 718 is remarkably refined by the TiC particles, and the reinforcement particle significantly impede the growth of columnar grain in the solidification process.
A Review of Bone Graft Substitutes Made From HA-Polymer Composite Scaffolds and Fabrication Potential With Laser-Based Additive Manufacturing Processes
Authors: Wu Hera , Lei Shuting
Published: September 2015

Hydroxyapatite, a bioactive ceramic, has been combined with biodegradable polymers to create composite three-dimensional interconnected porous scaffolds for bone graft substitutes. The materials and fabrication methods of these composite scaffolds are reviewed. The resulting mechanical and biological properties of scaffolds produced from the combination of certain materials and fabrication methods are analyzed. Requirements for a bone graft substitute and third generation scaffolds with the addition of osteoinductive and osteogenic features to composite scaffolds including biomolecule delivery and cell seeding are also introduced. Finally, the benefits of using additive manufacturing technologies to enable high level of control over the design of interconnected pore structure are discussed.
Fabrication of 3D Scaffolds via E-Jet Printing for Tendon Tissue Repair
Authors: Wu Y. , Fuh J. Y. H. , Wong Y. S. , Sun J.
Published: September 2015

Current clinical grafts used in tendon treatment are subject to several restrictions and there is a significant demand for alternative engineered tissue. The previously reported tendon scaffolds mainly based on electrospinning and textile technologies showed promising results for tendon regeneration. However, limitations, such as small pore size, nutrition transmission, cell attachment, exist universally in such scaffolds. In this work, a novel tissue engineered polycaprolactone (PCL) tendon scaffold based on electrohydrodynamic jet printing (E-Jetting) was developed for investigation. In preliminary in-vitro study, human tenocytes were seeded in scaffolds with pore size of ∼106 μm to investigate the cell attachment, morphology and alignment. This study suggested that E-jetted tendon scaffold highly mimicked hierarchical construction from fiber to fascicle level of the native tendon, and has potential to be an alternative tendon regeneration tool.
Effect of Variable Blank Holder Force on the Springback and Weld-Line Movement During Draw-Bending of Tailor Welded Blanks
Authors: Dawood Bishoy M. , Shazly Mostafa , Wifi Abdalla S. , El-Mokadem Alaa
Published: September 2015

Tailor welded blanks (TWBs) manufactured by drawing processes suffer from two major defects; weld-line movement (WLM) and springback. These defects can be reduced by using a counterpunch or controlling the value of the blank holder force and its scheme. This work presents a finite element analysis of the effect of variable blank holder force (VBHF) on springback and WLM of bench mark problem of draw-bending process of a TWB. The proposed VBHF scheme is developed based on the reaction forces predicted in a finite element model for artificially clamped weld-line case. The results obtained by applying VBHF are compared with those obtained using a counterpunch. The use of counterpunch is found to eliminate Vertical WLM in all the considered cases. Whereas side WLM using VBHF is found to be less than that obtained using counterpunch. When compared to the counterpunch technique, the springback values are found to be improved by applying the VBHF schemes.
Rotary Ultrasonic Machining of Carbon Fiber Reinforced Plastics: A Design of Experiment
Authors: Fernando P. K. S. C. , Pei Z. J. , Zhang Meng , Song Xiaoxu , Cong Weilong
Published: September 2015

Carbon fiber reinforced plastics (CFRP) have a wide-spread engineering applications due to their superior properties however, their machining cost is high. Cost effective machining processes are needed for CFRP. Rotary ultrasonic machining (RUM) is a nontraditional machining process for CFRP. RUM utilizes a rotating tool with ultrasonic vibration along the axial direction. Drilling is the most commonly needed machining practice for CFRP. In this study, a drilling test was conducted to investigate input variables, i.e. ultrasonic power, tool rotation speed, and feedrate for RUM of CFRP. A two-level three-factor full factorial design was used for experiment. The design of experiment approach was used to obtain main effects, two-factor interactions, and three-factor interactions on cutting force, torque, and surface roughness.
Effects of Tool Positions in Accumulated Double-Sided Incremental Forming on Part Geometry
Authors: Ren Huaqing , Moser Newell , Zhang Zixuan , Ndip-Agbor Ebot , Smith Jacob , Ehmann Kornel F. , Cao Jian
Published: September 2015

In Accumulated Double-Sided Incremental Forming (ADSIF), two hemispherical tools impart the local deformation to the sheet via their programmed in-plane spiral motion and the depth of the part is achieved via rigid body motion of the already formed part. Unlike Single Point Incremental Forming (SPIF) and Double-Sided Incremental Forming (DSIF), ADSIF does not impose forces on the already-formed part and therefore, has the potential of achieving higher geometric accuracy. A systematic method is proposed in this work to study the influences of the relative tool positions on the local formed shape and the final geometry, which is essentially the accumulation of all previously formed local deformations. Meanwhile, the concepts of the stable angle and the peak angle are introduced to better describe the cross-sectional geometry of a formed part with a constant wall angle at that particular cross-section. It is recommended, while multiple combinations of the relative positions of two forming tools may achieve the same stable angle, that the positioning parameters should be chosen such that the resultant forming force or the wall angle variation between the stable and peak angles is minimized.
A Novel Method Based on Adjusted Sample Entropy for Process Capability Analysis in Complex Manufacturing Processes
Authors: Kong Xianguang , Chang Shing I. , Zhang Zheng
Published: September 2015

As manufacturing systems become increasingly complex, manufacturing enterprises face the challenging need for precise, effective process capability analyses. However, acquisition of process data, characterized by larger volume and complexity, is much easier, consequently making process capability analysis more difficult. Traditional process capability analysis methods such as Cp or Cpk are not adequate for large volume process data collected over time because these methods assume that process distribution remains unchanged. Therefore, the goal of this paper is to explore the use of sample entropy (SampEn) as it relates to univariate process capability analysis. The proposed method, which alleviates the fixed distribution assumption, can identify changing process variations over time. We proposed a novel method based on Adjusted Sample Entropy (AdSEn) to quantify process variation changes. A study based on simulation data sets showed that the proposed method provides adequate process capability information.
Effect of Toolpath on the Springback of 2024-T3 Aluminum During Single Point Incremental Forming
Authors: Reese Zachary C. , Ruszkiewicz Brandt J. , Nikhare Chetan P. , Roth John T.
Published: September 2015

Incremental forming is a nontraditional forming method in which a spherical tool is used to asymmetrically deform sheet metal without the need for expensive allocated dies. Incremental forming employs a tool path similar to that used when CNC milling. Hence, when forming a part, the forming tool makes a series of passes circumferentially around the workpiece, gradually spirally stepping down in the z-axis on each sequential pass. This tool path deforms the sheet metal stock into the final, desired shape. These passes can start from the outer radius of the part and work in (Out to In, OI forming) or they can start from the center of the shape and work outward (In to Out, IO forming).

As with many sheet metal operations, springback is a big concern during the incremental forming process. During the deformation process, residual stresses are created within the workpiece causing the final formed shape to springback when it is unclamped, sometimes very significantly. The more complex the geometry of the final part and the more total deformation that occurs when forming the geometry, the greater the residual stresses that are generated within the part. The residual stresses that have built up in the piece cause more significant distortion to the part when it is released from the retaining fixturing. This paper examines how the step size (in the z direction), OI vs. IO forming, and final part geometry affect the total springback in a finished piece. For all of these tests 0.5 mm thick sheets of 2024-T3 aluminum were used to form both the truncated pyramid and truncated cone shape. From this investigation it was found that smaller step sizes result in greater springback, IO is significantly less effective in forming the part (due to workpiece tearing), and final part geometry plays an important role due to the creation of residual stresses that exist in corners.
Design of a Continuous-Bending-Under-Tension Machine and Initial Experiments on Al-6022-T4
Authors: Roemer Timothy J. , Kinsey Brad L. , Korkolis Yannis P.
Published: September 2015

An experimental technique called Continuous-Bending-Under-Tension (CBT) can produce elongations over two times that of a standard tensile test by preventing the necking instability from occurring. This is achieved by superposing plastic bending on tension along the gage length of the material using three rollers. The specimen is kept under tension as the rollers apply the three point bending and cyclically transverse along the gage length. This localizes the plastic deformation by subjecting the specimen to bending-under-tension. Details on the design of the unique CBT machine and some preliminary results for the CBT research being conducted are presented here. These results include CBT tests where the roller depth was varied to demonstrate the increased elongation compared to the traditional tension test, CBT repeatability, and a modified friction test using the CBT machine.
Comparison of the Effects of Down Milling and Up Milling on the Tool Temperature in Machining of Ti-6Al-4V
Authors: Ma Jianfeng , Qiu Changqing , Lei Shuting
Published: September 2015

Ti-6AL-4V is widely used in the industry for the high strength-to-weight ratio at elevated temperature, its excellent resistance to fracture and corrosion, and biological properties. However, Ti-6AL-4V is hard to manufacture for its reactive chemical properties and low thermal conductivity that causes high temperature on the tool surface. Prediction of the tool temperature distribution from different manufacturing ways, up and down milling, has great significance in predicting tool wear pattern (cutting speed, feed/tooth, and axial depth of cut) in corner milling on temperature of the tool rake face. The tool material used is general carbide and Johnson-Cook plastic model is utilized to model the behavior of the workpiece Ti-6AL-4V. A separate Abaqus heat transfer model is used to analyze the heat transfer process after the tooth disengages the workpiece and before it engages the workpiece again to predict change of temperature distribution during this cooling process. The comparison of the up milling and down milling on the tool temperature is conducted.
Effects of Reinforcement Particle Size on Cold Roll Bonded (CRB) Al1100 Laminate Composites
Authors: Bastwros Mina , Liu Miao , Orlowsky Nicholas , Kim Gap-Yong
Published: September 2015

Cold roll bonding (CRB), a fabrication process that proceeds at room temperature, has been widely used in fabricating large-scale sheet metal composites. In this study, the effect of reinforcement particle sizes, ranging from nanoscale to microscale, on the bond strength of cold roll bonded aluminum silicon carbide (Al-SiC) composites has been investigated. The bond strength was measured by the T-peel test. Scanning electron microscope was employed to study the bonding behavior at the interface of the laminate composites. Nanoparticles failed to increase the bond strength compared with the unreinforced Al sample. On the other hand, relatively large particles (tens of micrometers) increased the bond strength noticeably due to the mechanical interlocking introduced by the particles. For the largest particle (60 μm) used in this study, the bond strength was large enough to tear the Al1100 strip during the T-peel test.
Investigation of the Relationship Between Vibration Data and Tool Wear During End-Milling of Gamma-Prime Strengthened Alloys
Authors: Bardis Vasileios , Niaki Farbod Akhavan , Ulutan Durul , Mears Laine
Published: September 2015

Condition Based Maintenance (CBM) systems are crucial for today’s high accuracy machining of exotic materials. For reliable results, CBM systems need early and reliable warning based on prediction models that use multiple types of sensors. In this study, tool flank wear during end milling difficult-to-machine alloys was measured using an optical microscope. Then, vibration data collected with an accelerometer was investigated for its relationship to tool flank wear. The developed relationship between accelerometer output and tool flank wear was validated with further experiments. It was observed from frequency domain responses of these outputs that specific harmonics of the tool pass frequency were dominant, and tool flank wear can be related to the amplitude of these harmonics during machining. This way, it was shown that through accurate online prediction of tool wear, premature interruption of the process as well as machining with a worn tool can both be avoided, improving end-product quality as well as reducing machining costs.
Deformation Evaluation of Part Overhang Configurations in Electron Beam Additive Manufacturing
Authors: Cheng Bo , Chou Kevin
Published: September 2015

Powder-bed electron beam additive manufacturing (EBAM) has emerged as a cost-effective process for many industrial applications. Intuitively, EBAM would not require support structures for overhang geometry because the powder bed would self-support the overhang weight. However, without a proper support structure, overhang warping actually occurs in practices. In this study, a two dimensional (2D) finite element (FE) model was developed to study the thermomechanical process of EBAM. The model was applied to evaluate (1) the process parameter effect, (2) the overhang and support configuration effect, and (3) the powder porosity effect on overhang deformations. The major results are summarized as follows. (1) Increasing the beam speed and diameter will result in less deformation in an overhang area, while increasing the beam current will worsen the deformation condition. (2) A smaller tilt angle will cause a larger overhang deformation. (3) A support column, even placed away from the solid substrate side, will minimize overhang deformations. (4) An anchor-free solid piece beneath the overhang can reduce the deformation with an appropriate gap. (5) A lower powder porosity level may alleviate overhang deformations.
Analytical Modeling of Ultrasonic Vibration Assisted Drilling of Bones for Medical Surgical Applications
Authors: Kong Fanxia , Lee Yuan-Shin
Published: September 2015

This paper presents a new analytical modeling of ultrasonic vibration assisted drilling of bones for medical surgery operations. Due to the heterogeneous bone structure and the uneven bone surface, bone surgery cutting suffers from inaccuracy and difficulty in high precision bone surgery cutting. In this paper, a new method of ultrasonic vibration assisted drilling is proposed for bone surgery cutting. An analytical force modeling is presented for ultrasonic vibration assisted bone drilling. Experimental result validates the analytical modeling presented in the paper. Preliminary testing result also shows a significant improvement of drilling accuracy based on the proposed ultrasonic vibration assisted bone drilling. The proposed cutting techniques can be used in bone cutting surgery to increase the accuracy of born drilling position and reduce trauma damage of bone and surrounding soft tissues.
Strip Flatness Mechanism Analysis in Single-Stand Cold Mills
Authors: Zhang Feng , Malik Arif S.
Published: September 2015

Manufacturing high-strength and light-weight (thin gauge) sheet metals presents challenges in the cold rolling processes. Primary reasons are the difficult-to-predict effectiveness of the various flatness control mechanisms, and the associated evolution of roll stress amplitudes. The purpose of this paper is to demonstrate simulations that provide insights into the behavior of various sheet flatness control mechanisms, including roll bending and roll shifting on 4-high and 6-high single stand mills. An efficient, static mathematic model is utilized to analyze mill deflections, strip thickness profiles, and roll stresses. While appropriate roll ‘sizing’ is crucial in designing mills to be competitive for intended products, this requires practical insights into flatness mechanism behavior and peak roll stress characteristics. The knowledge gained from the simulations in this work can assist in interpreting results of automated computational sizing optimization models. Further, it may provide better understanding of general mill deflection behaviors, and help identify interesting situations such as when the peak stress location changes, or wedge type strip thickness profile effects are induced incidentally by specific flatness control mechanisms.
Physical and electrical characteristics of hydrothermally synthesized nanocrystalline TiO2 thin films
Authors: Cheng Chin-Lung , Jeng Jin-Tsong , Yang Jung-Yen , Cheng Tsung-Chieh , Liu Chi-Chung
Published: September 2015

A discrete nanocrystalline titanium dioxide thin film was hydrothermally synthesized from titanium, and acted as the charge trapping layer for a nonvolatile memory device. The nanoparticulate thin film was composed of TiO2 nanocrystals with a diameter of approximately 5–20 nm and a surface density of ∼1 × 1012 cm−2. Anatase TiO2 nanocrystals were observed, and the growth mechanism of the nanoparticulate TiO2 film was investigated. The density of charge trap states was estimated to be approximately 3.15 × 1013 cm−2 in a large, flatband, 9-V voltage-shift hysteresis window, which was explored by scanning over ±7 V.
Effect of GaN surface treatment on Al2O3/n-GaN MOS capacitors
Authors: Hossain Tashfin , Wei Daming , Edgar James H. , Garces Nelson Y. , Nepal Neeraj , Hite Jennifer K. , Mastro Michael A. , Eddy Charles R. , Meyer Harry M.
Published: September 2015

The surface preparation for depositing Al2O3 for fabricating Au/Ni/Al2O3/n-GaN (0001) metal oxide semiconductor (MOS) capacitors was optimized as a step toward realization of high performance GaN MOSFETs. The GaN surface treatments studied included cleaning with piranha (H2O2:H2SO4 = 1:5), (NH4)2S, and 30% HF etches. By several metrics, the MOS capacitor with the piranha-etched GaN had the best characteristics. It had the lowest capacitance–voltage hysteresis, the smoothest Al2O3 surface as determined by atomic force microscopy (0.2 nm surface roughness), the lowest carbon concentration (∼0.78%) at the Al2O3/n-GaN interface (from x-ray photoelectron spectroscopy), and the lowest oxide-trap charge (QT = 1.6 × 1011 cm−2eV−1). Its interface trap density (Dit = 3.7 × 1012 cm−2eV−1), as measured with photon-assisted capacitance– voltage method, was the lowest from conduction band-edge to midgap.
Analytic reconstruction algorithms for triple‐source CT with horizontal data truncation
Authors: Chen Ming , Yu Hengyong
Published: September 2015

Purpose:

This paper explores a triple‐source imaging method with horizontal data truncation to enlarge the field of view (FOV) for big objects.

Methods:

The study is conducted by using theoretical analysis, mathematical deduction, and numerical simulations. The proposed algorithms are implemented in c + + and matlab. While the basic platform is constructed in matlab, the computationally intensive segments are coded in c + +, which are linked via a mex interface.

Results:

A triple‐source circular scanning configuration with horizontal data truncation is developed, where three pairs of x‐ray sources and detectors are unevenly distributed on the same circle to cover the whole imaging object. For this triple‐source configuration, a fan‐beam filtered backprojection‐type algorithm is derived for truncated full‐scan projections without data rebinning. The algorithm is also extended for horizontally truncated half‐scan projections and cone‐beam projections in a Feldkamp‐type framework. Using their method, the FOV is enlarged twofold to threefold to scan bigger objects with high speed and quality. The numerical simulation results confirm the correctness and effectiveness of the developed algorithms.

Conclusions:

The triple‐source scanning configuration with horizontal data truncation cannot only keep most of the advantages of a traditional multisource system but also cover a larger FOV for big imaging objects. In addition, because the filtering is shift‐invariant, the proposed algorithms are very fast and easily parallelized on graphic processing units.
Individual and sex distinctiveness in bark calls of domestic chinchillas elicited in a distress context
Authors: Moreno-Gómez Felipe N. , León Alex , Velásquez Nelson A. , Penna Mario , Delano Paul H.
Published: September 2015

Animals obtain information about their social environment by means of communication signals, which provide relevant subtle cues for individual recognition. An important requisite for this process is the existence of larger between- than within-emitter signal variation. Acoustic signals are complex traits susceptible of variation in their spectral and temporal components, implying that signal distinctiveness can result from differences in single or various acoustic components. In this study, domestic chinchillas were induced to vocalize in a distress context to describe the acoustic characteristics of the bark calls, and to determine features that denote the potential value of this vocalization for individual and/or sexual recognition. The results demonstrate that the variation in spectral and temporal components of the bark calls of chinchillas elicited under a distress context is larger between than within individuals, suggesting the potential of these signals for distinctiveness between individual signalers, although the potential of this call type for sex distinctiveness is quite limited. These results combined with previous studies on auditory capabilities of chinchillas contribute to position this rodent as a valuable model species for studying auditory–vocal interactions.