bluuebunny/crossref_metadata_2025 huggingface dataset:
AFM-Based Nanofabrication: Modeling, Simulation, and Experimental Verification
Authors: Promyoo Rapeepan , El-Mounayri Hazim , Karingula Varun Kumar , Varahramyan Kody
Published: November 2013

Recent developments in science and engineering have advanced the fabrication techniques for micro/nanodevices. Among them, atomic force microscope (AFM) has already been used for nanomachining and fabrication of micro/nanodevices. In this paper, a computational model for AFM-based nanofabrication processes is being developed. Molecular Dynamics (MD) technique is used to model and simulate mechanical indentation and scratching at the nanoscale. The effects of AFM-tip radius and crystal orientation are investigated. The simulation is also used to study the effect of the AFM tip speed on the indentation force at the interface between the tip and the substrate/workpiece The material deformation and indentation geometry are extracted from the final locations of atoms, which are displaced by the rigid indenter. Material properties including modulus of elasticity and hardness are estimated. It is found that properties vary significantly at the nanoscale. AFM is used to conduct actual nanoindentation and scratching, to validate the MD simulation. Qualitative agreement is found. Finally, AFM-based fabrication of nanochannels/nanofluidic devices is conducted using different applied forces, scratching length, and feed rate.
Modelling of Thin-Film Single and Multi-Layer Nanosecond Pulsed Laser Processing
Authors: Lutey Adrian H. A.
Published: November 2013

A complete model of nanosecond pulsed laser scribing of arbitrary thin multi-layer structures is presented. The chain of events is separated according to time-scale; an initial simulation considers material response during the pulse; another combines this result with the much slower effects of heat flow away from the laser axis. The former considers heating, vaporisation and phase explosion of metals in the course of a single pulse, accounting for variations in thermal conductivity and optical absorption as the material becomes superheated and approaches its critical temperature. The latter calculates the bidimensional heat flow in a complete multi-layer structure over the course of a scribing operation, combining material properties and considering removal by both short-pulse ablation and long-term heating of the work piece. Simulation results for the single pulse ablation of an aluminium target align well with published experimental data both in terms of phase explosion threshold and ablation depth as a function of fluence. Bidimensional heat flow simulations of a polypropylene–aluminium–polypropylene triplex structure reveal the progression of events towards steady state behaviour; aluminium ejected due to short-pulse ablation and plastic removed due to conduction.
Design of a 3-DOF Compliant Parallel Mechanism for Displacement Amplification
Authors: Zeng Qiang , Ehmann Kornel F.
Published: November 2013

Prevalent general design methods and applications of compliant displacement amplifiers are focused on 1-DOF units composed into serial structures, which are limited by their output motions, stiffness, heat balance, repeatability and resonant frequencies. To improve the output properties of compliant displacement amplifiers, a monolithic structure is presented in the form of a compliant parallel mechanism. In the proposed moving structure, the compliant mechanism of the displacement amplifier is designed with 3-DOF to generate uniformly magnified output properties in all directions. High first resonant frequencies and amplification ratios are achieved in a compact size compared to existing compliant displacement amplifiers. The related kinematics, amplification ratios and resonant frequencies of the amplifier are analytically modeled, and the results are simulated by finite-element analysis. The proposed design is employable for micro/nano positioning stages operating within a prismatic output workspace.
Micro-Milling Responses of Hierarchical Graphene Composites
Authors: Chu Bryan , Samuel Johnson , Koratkar Nikhil
Published: November 2013

The objective of this research is to examine the micro-machining responses of a hierarchical three-phase composite made up of micro-scale glass fibers that are held together by an epoxy matrix laden with nano-scale graphene platelets. To this end, micro-milling experiments are performed on both the hierarchical graphene composite as well as on a baseline two-phase glass fiber composite without the graphene additive. The composite microstructure is characterized using transmission electron microscopy and scanning electron microscopy methods. Tool wear, chip morphology, cutting force, surface roughness and delamination are employed as machinability measures. In general, the tool wear, cutting forces, surface roughness and extent of delamination are all seen to be lower for the hierarchical graphene composite. These improvements are attributed to the fact that graphene platelets improve the thermal conductivity of the matrix, provide lubrication at the tool-chip interface and also improve the interface strength between the glass fibers and the matrix. Thus, the addition of graphene to a conventional two-phase glass fiber epoxy composite is seen to not only improve its mechanical properties but also its machinability.
A Study of the Impact of Workpiece Location on Machining Performance of a 2-DoF PKM Based Machine Tool
Authors: Rao A. B. Koteswara , Darvekar Sanjay , Ramji K.
Published: November 2013

This paper presents the impact of workpiece location on the machining performance of a 2-degree of freedom Parallel Kinematic Machine (PKM) tool. The PKM behavior is highly non-uniform and depends on the tool position within the workspace. The structural deformation and vibration due to cutting loads affect the quality of machined surfaces. The aim of the present study is to find the optimal tool position (workpiece location) where the workpiece is machined to a specific quality level. End-milling operations are carried out at various locations within the workspace and the surface roughness of machined surface (Ra) is measured at each location. A regression model is developed to predict the surface roughness. The study shows that the workpiece location has significant impact upon surface roughness of the machined part. Finally, a suitable workspace is defined for end-milling operation.
Cloud Manufacturing: Drivers, Current Status, and Future Trends
Authors: Wu Dazhong , Greer Matthew J. , Rosen David W. , Schaefer Dirk
Published: November 2013

Cloud Manufacturing (CM) refers to a customer-centric manufacturing model that exploits on-demand access to a shared collection of diversified and distributed manufacturing resources to form temporary, reconfigurable production lines which enhance efficiency, reduce product lifecycle costs, and allow for optimal resource loading in response to variable-demand customer generated tasking. Our objective is to present the drivers, current status of research and development, and future trends of CM. We also discuss the potential short term and long term impacts of CM on various sectors.
Adaptive Robust Control of Circular Machining Contour Error Using Global Task Coordinate Frame
Authors: Davis Tyler A. , Shin Yung C. , Yao Bin
Published: November 2013

The contour error of machining processes is defined as the difference between the desired and actual produced shape. Two major factors contributing to contour error are axis position error and tool deflection. A large amount of research work formulates the contour error in convenient locally defined task coordinate frames that are subject to significant approximation error. The more accurate global task coordinate frame (GTCF) can be used, but transforming the control problem to the GTCF leads to a highly nonlinear control problem. An adaptive robust control (ARC) approach is designed to control machine position in the GTCF, while directly accounting for tool deflection, to minimize the contour error. The combined GTCF/ARC approach is experimentally validated by applying the control to circular contours on a three axis milling machine. The results show that the proposed approach reduces contour error in all cases tested.
Modeling of Multi-Cell Lithium-Ion Battery Packs for Electric Vehicles Considering Effects of Manufacturing Processes
Authors: Wang Chongye , Wang Yong , Li Lin , Shao Hua , Wu Changxu
Published: November 2013

Electric vehicle (EV) technologies have received great attention due to the potential contributions to relieving the energy dependence on petroleum and reducing carbon dioxide emissions. The advancement of EV technologies greatly relies on the development of battery technologies. Lithium-ion (Li-ion) batteries have recently become the main choice as the power source for major EV manufacturers. Previous research on EV Li-ion batteries is mainly focused on materials and chemical properties of single cells, while the effects of manufacturing processes on the performance of entire battery packs have almost been neglected. In practice, EV batteries are used in packs containing multiple cells, which may not be ideally manufactured. This research proposes a novel modeling method for analyzing the effects of manufacturing processes on the dynamics of EV Li-ion battery packs. The method will help engineers gain a deeper understanding of the roles of manufacturing processes in improving EV Li-ion battery performance.
The State of the Art of Cloud Manufacturing and Future Trends
Authors: Adamson Göran , Wang Lihui , Holm Magnus
Published: November 2013

Cloud manufacturing has emerged as a new manufacturing paradigm, which combines technologies (such as Internet of Things, Cloud computing, semantic Web, virtualisation and service-oriented technologies) with advanced manufacturing models, information and communication technologies. It aims to be networked, intelligent, service-oriented, knowledge-based and energy efficient, and promises a variety of benefits and advantages by providing fast, reliable and secure on-demand services for users. It is envisioned that companies in all sectors of manufacturing will be able to package their resources and know-hows in the Cloud, making them conveniently available for others through pay-as-you-go, which is also timely and economically attractive. Resources, e.g. manufacturing software tools, applications, knowledge and fabrication capabilities, will then be made accessible to presumptive consumers on a worldwide basis. After surveying a vast array of available publications, this paper presents an up-to-date literature review together with future trends and research directions in Cloud manufacturing.
Interface Delamination of Diamond-Coated Carbide Tools Considering Coating Fractures by XFEM
Authors: Lu Ping , Chou Kevin
Published: November 2013

Interface delamination is the major failure mode of diamond-coated carbide tools in machining. On the other hand, coating cracking is possibly accompanied during a tribological process that induces the delamination phenomenon. However, such an influence between the two failure behaviors has not been investigated in a quantitative way to better understand and design diamond coating tools.

In this study, a three-dimensional (3D) indentation model combining cohesive interactions and extended finite element method (XFEM) was developed to investigate the diamond-coating, carbide-substrate interface behavior with the incorporation of coating cracking. The interface interaction was based on a cohesive zone model (CZM) with a bilinear traction-separation law. XFEM was applied to the coating domain to model cracking in the diamond coating with a damage criterion of the maximum principal stress. Deposition stresses were also included to investigate their effect on the coating delamination and fractures. The model was implemented in finite element (FE) codes to analyze the cone crack in brittle coatings, as well as the interface delamination of diamond coated carbide tools. The XFEM model was validated by the indentation testing data from literature in crack initiations and propagations in brittle materials. FE results from the indentation on diamond-coated tools show that the interface delamination size and the loading force become smaller when coating fractures are incorporated in the model, and the deposition stresses will increase the initial crack radius as well as the critical load for delamination in diamond coatings.
Investigation and Optimization of Laser Welding of Ti-6Al-4V Titanium Alloy Plates
Authors: Caiazzo Fabrizia , Alfieri Vittorio , Corrado Gaetano , Cardaropoli Francesco , Sergi Vincenzo
Published: November 2013

Titanium alloys are employed for several applications, ranging from aerospace to medicine. In particular, Ti-6Al-4V is the most common, thanks to an excellent combination of low density, high specific strength and corrosion resistance.

Laser welding has been increasingly considered as an alternative to traditional techniques to join titanium alloys. An increase in penetration depth and a reduction of possible welding defects is achieved indeed; moreover a smaller grain size in the fused zone is benefited in comparison to either TIG and plasma arc welding, thus providing an increase in the tensile strength of the welded structures.

The aim of this work is to develop the regression model for a number of responses which are crucial for the feature of the joint. The study was carried out on 3 mm thick Ti-6Al-4V plates; a square butt welding configuration was considered employing a disk-laser source. A 3-level factorial plan was hence arranged in a face-centred cubic scheme. The responses were analyzed referring to the governing parameters. Then, an optimization was carried out via statistical tools, in order to find the optimal welding set-up for the alloy under examination.
Quality Evaluation of Multistage Manufacturing Systems by Jointly Considering the Incoming Part Quality and System Conditions
Authors: Zhang Faping , Li Jingjing , Yan Yan , Lu Jiping , Tang Shuiyuan
Published: November 2013

The quality performance of a multistage manufacturing systems (MMS) is jointly affected by incoming part quality, system condition unreliability due to batch-to-batch uncertainty, making it challenging to evaluate the quality performance of MMS. Previous research considered the incoming part quality and system conditions separately in systematic level. This paper aims to fill the gap by considering the joint effects of these two aspects to evaluate quality performance of a MMS from historical production data driven work. A system quality model was derived to predict the probability of producing good parts at each stage and entire MMS when the incoming good part quality rate and station conditions were given. To overcome the inconvenience of the quality model for its nonlinear transfer function, the concept of quality efficiency was developed to depict the joint effectiveness of incoming part quality and system conditions mathematically at each stage. Based on the quality model, on the paper also discusses how to maintain high good product quality rate. The results of this study suggested a possible approach of evaluating the impacts of system conditions on product quality. The results of the model will lead to guidelines of quality management in multistage manufacturing systems.
The Establishment of Coupled Electromagnetic-Thermal Analytical Model of Induction Heating System With Magnetic Flux Concentrator and the Study on the Effect of Magnetic Permeability to the Modeling
Authors: Zhu Tianxing , Li Xuekun , Li Feng , Rong Yiming (Kevin)
Published: November 2013

Induction heating is frequently used in the metalworking industry to heat metals for hardening, soldering, brazing, tempering and annealing. Due to its complexity, the using of simulation to analyze the induction heating process could become very advantageous both in design and economic aspects. In this paper, an analytical model is established using commercial package Cedrat Flux® 10.3, and the model is verified by the experiments. After the establishment of analytical model, an analysis on the effect of workpiece magnetic permeability to the modeling was conducted.
Model Learning in a Multistage Machining Process: Online Identification of Force Coefficients and Model Use in the Manufacturing Enterprise
Authors: Mehta Parikshit , Mears Laine
Published: November 2013

This work presents a systems approach in machining process control. Traditional force-based machining process control has been focused on single machine-single operation. The force or power sensor is used to measure the instantaneous force/power, and control action is taken by changing the feedrate in real time to follow a given force setpoint. The application of such control has successfully been implemented to prevent chatter and to elongate tool life by minimizing tool wear. This research seeks to extend the application of control algorithms to learn about the machining system (comprised in this context of a workpiece being operated on in progressive machining), and how knowledge generated by the process can be passed on to the next process for optimization. To demonstrate this, turning of a partially hardened bar is explored. A nonlinear mechanistic force model-based control framework attempts to control the cutting force at a designated setpoint, with material properties changing over the cut. The force coefficients for the material are calculated offline using experimental data and Bayesian inference methods. Since the hardened part of the bar will shift the force coefficient values, an online estimation strategy (Bayesian Recursive Least Square estimator) is used to learn the new coefficients as well as satisfying the control objective. With the newly learned coefficients passed downstream, the subsequent operation experiences no compromise of control objective as well reduces the maximum values of force encountered. Numerical analyses presented show the adaptation and control scheme performance.
Phase Transformation Affected Quench Crack Study Using Finite Element Analysis
Authors: Li Zhichao (Charlie) , Ferguson B. Lynn
Published: November 2013

Steel components are commonly heat treated to obtain favorable mechanical properties for enhanced performance. Quench hardening is one of the most important heat treatment processes to increase hardness and strength. During quenching, both thermal gradients and phase transformations contribute to the evolution of internal stresses. Higher tensile stresses in a part during quenching tend to increase the cracking possibility, which is more problematic for components with various section sizes due to stress concentration. Heat treaters believe that cracking possibility increases with larger difference of section size in a part. This is only true in some cases. If the section size difference exceeds a threshold, the cracking possibility will decrease. Due to the complex part’s responses to thermal gradient, phase transformation and unbalanced geometry, there is no robust and simple rule to characterize the cracking possibility. With the development of more advanced heat treatment computer modeling capability, the material’s response during heat treatment can be more intuitively understood. The part geometry and heat treatment process can be designed with much less potential heat treatment defects. In this paper, finite element based heat treatment software, DANTE, is used to investigate the relationship between section size difference and cracking possibility by using parts with a series of section size ratios. In this specific study, the selected part is a plain strain component made of AISI 9310. The results during oil quench process have shown that a section size ratio of 1:2 creates the highest stress concentration and cracking possibility.
Developing an Agility Model for Maximum Responsiveness to the Changes in Customer Requirements for SMEs
Authors: Gadalla Mohamed A.
Published: November 2013

Small and Medium Size Enterprises (SMEs) face increased market pressure due to demand fluctuation and the shift of the consumer focus from high volume/low mix to high mix/low volume environment. Costumer requirement as seen by SME’s can be summarized as: quantity scaling, unpredicted and sudden demands, on-time and quicker delivery times, and increased number of customized products. This paper proposes an agility realization model for SMEs to achieve higher responsiveness to these requirements. The agility model is based on integrating four main agility enablers: quick manufacturing response strategies, multi channel manufacturing approach, high mix/low volume techniques and collaborative networks. A case study is presented to demonstrate the proposed approach. The framework presented in this paper represents a roadmap for SMEs to raise their internal efficiency, achieve maximum responsiveness that will increase their competitive edge.
Modeling, Analysis, and Improvement of Door Production Line at an Automotive Body Shop
Authors: Zhao Cong , Li Jingshan
Published: November 2013

In this paper, we introduce a case study of modeling, analysis, and continuous improvement of a door production line at an automotive body shop using production systems engineering methods. Analytical models have been developed, and recursive procedures have been derived to evaluate line production rate. An arrow-based bottleneck analysis method is introduced to identify the bottlenecks, whose improvement can lead to the largest improvement in system performance. Such methods provide a quantitative tool for plant engineers and managers to operate and improve door production line to achieve high productivity, and are also applicable to other large volume manufacturing systems.
Experimental Study on Micro-Scale Milling Process Using Electro-Hydro-Dynamic (EHD) Spray Lubrication With Chilly Air
Authors: Lee Pil-Ho , Kim Dae Hoon , Lee Sang Won
Published: November 2013

This paper investigates the characteristics of a micro-scale end-milling process using the electro-hydro-dynamic (EHD) spray lubrication with chilly air. A new hybrid cooling and lubrication system was developed by integrating EHD spray and chilly air supply modules. In the experiments, the milling forces and burr formation are observed according to varying cooling and lubrication conditions. It is demonstrated that the developed new hybrid cooling and lubrication system can reduce milling forces and burrs significantly.
Improving Densification of Zirconium Tungstate With Nano Tungsten Trioxide and Sintering Aids
Authors: Wang M. , Kwon P.
Published: November 2013

Because of the highly negative thermal expansion coefficient, zirconium tungstate (ZT) offers a unique opportunity in engineering applications. However, processing of ZT has not been fully perfected to yield a near thoeretical density. Thus, ZT has relatively a weak strength, which prevented its unique property to be fully utilized in applications. This study investigates the processing methods to improve the packing and subsequent final densities — thus improving the mechanical strength. These methods include (1) use of a wide variety of powders with different size, (2) use of nano-powders and (3) use of sintering aids. Under the same compaction and sintering condition, a variety of powder mixtures were produced, whose initial packing density and final sintered density were measured and compared in order to determine the optimal combination. The elastic modulus of each sample was also tested. By adding nanopowders, the sintered density of zirconium tungstate can be enhanced by 5%. Furthermore, with the sintering aids, the density can be improved by additional 5%. The optimal amount of nanopowders and sintering aids were determined to improve the final density and strength.
Combined Temperature and Force Control for Robotic Friction Stir Welding
Authors: Fehrenbacher Axel , Smith Christopher B. , Duffie Neil A. , Ferrier Nicola J. , Pfefferkorn Frank E. , Zinn Michael R.
Published: November 2013

The objective of this research is to develop a closed-loop control system for robotic friction stir welding (FSW) that simultaneously controls force and temperature in order to maintain weld quality under various process disturbances. FSW is a solid-state joining process enabling welds with excellent metallurgical and mechanical properties, as well as significant energy consumption and cost savings compared to traditional fusion welding processes.

During FSW, several process parameter and condition variations (thermal constraints, material properties, geometry, etc.) are present. The FSW process can be sensitive to these variations, which are commonly present in a production environment; hence, there is a significant need to control the process to assure high weld quality. Reliable FSW for a wide range of applications will require closed-loop control of certain process parameters.

A linear multi-input-multi-output process model has been developed that captures the dynamic relations between two process inputs (commanded spindle speed and commanded vertical tool position) and two process outputs (interface temperature and axial force).

A closed-loop controller was implemented that combines temperature and force control on an industrial robotic FSW system. The performance of the combined control system was demonstrated with successful command tracking and disturbance rejection. Within a certain range, desired axial forces and interface temperatures are achieved by automatically adjusting the spindle speed and the vertical tool position at the same time. The axial force and interface temperature is maintained during both thermal and geometric disturbances and thus weld quality can be maintained for a variety of conditions in which each control strategy applied independently could fail.
Experimental Study of Biaxial Load-Unload Behavior of DP590 Steel Sheets
Authors: Korkolis Yannis P. , Deng Nengxiu , Kuwabara Toshihiko
Published: November 2013

Biaxial load-unload tests under radial paths in the true stress space were carried out for DP590 steel sheets using specially-designed cruciform specimens. Depending on the specific path, over 15% equivalent logarithmic plastic strain was achieved so that the load-unload behavior was successfully probed at relatively high strain levels. It was found that the stress-strain response at the initial load/unload follows the predicted linearly elastic response very well and that subsequently the slope decays. Following this initial phase, a second linear response is observed, which ultimately leads to the non-linear plastic response. The biaxial non-linear strain recovery components εxnl and εynl were measured to be on average approximately 11% of the elastic strains εxe and εye, respectively. At higher strains, this ratio is approximately 25%, indicating the inaccuracy of springback simulations when a linearly elastic unloading response is assumed. For each load-unload cycle, the dissipated energy density tends to increase with the progression of prestrain. The plastic work contours covering the first quadrant of the stress space were successfully constructed and the directions of the plastic strain rates were then calculated. A good agreement with the experimental facts was found by adopting the anisotropic yield function Yld2000-2D.
Energy Savings Opportunities of an Integrated Facility and Production Line
Authors: Brundage Michael P. , Chang Qing , Chen Dongmei , Yu Victor
Published: November 2013

In modern manufacturing facilities there are many energy saving opportunities (ESO) that are wasted by the lack of integration between the facility and the production system. This paper deals with an integrated production line and the heating, ventilation, and air conditioning (HVAC) system and explores the different energy saving opportunities of the two largest energy consumers in the manufacturing plant. The energy opportunity window of each machine is utilized to allow for energy savings for the production line without throughput loss on the floor. This opportunity window is synced with the peak periods of energy demand for the energy demand of the HVAC system. The integration of these two systems allows for the maximum energy cost savings. These systems are modeled and tested using simulation case studies.
Estimation of Milling Forces From Compliant Sensors Using a Harmonic Force Model and Kalman Filter
Authors: Koh Min Hyong , Nouri Mehdi , Fussell Barry K.
Published: November 2013

Force transducers such as the piezoelectric Kistler dynamometer and the wireless strain gage Smart Tool are used to monitor the cutting force during CNC machining. Due to sensor dynamics, there are differences between the actual cutting force and the measured force, characterized by phase delay and additional vibrations in the cutting profile. In this work, actual cutting forces are estimated from the measured sensor data using a Kalman filter. Since cutting forces are composed of harmonics of the tooth passing frequency and runout frequency, both a sensor dynamic model and harmonic cutting force model are included in the Kalman filter model in order to improve performance of the filter. The harmonic computations of the measured cutting force are used to self-tune the Kalman filter. Comparisons between the measured and estimated force show the ability of the Kalman filter to reduce sensor vibration and noise with no phase delay.
Alternative Control of an Electrically-Assisted Tensile Forming Process Using Current Modulation
Authors: Jones Joshua J. , Mears Laine
Published: November 2013

Electrically-assisted forming is a technique whereby metal is deformed while simultaneously undergoing electric current flow. Using this process, electric current level becomes a new degree of freedom for process control. In this work we present some alternative control architectures allowing for new avenues of control using such a process. The primary findings are architectures to allow for forming at constant force and forming at constant stress levels by modulating electric current to directly control material strength. These are demonstrated in a tensile forming operation, and found to produce the desired results. Combining these control approaches with previous and contemporary efforts in modeling of the process physics will allow for system identification of material response properties and model-based control of difficult-to-observe process parameters such as real time temperature gradients.
Three Dimensional Finite Element Analysis of Staggered Backward Flow Forming Process
Authors: Shinde Hemant , Mahajan Pushkar , Singh Ramesh , Narasimhan K.
Published: November 2013

Flow forming is one of the cold forming processes which is mainly used to produce thin-walled high-precision tubular components. A three dimensional coupled-field thermo-mechanical finite element model for staggered three-roller backward flow forming of a cylindrical workpiece of MDN-250 maraging steel has been developed using Abaqus/Explicit. In this model, the effect of tip radius of the rollers and friction between the rollers and the workpiece has been considered. The bottom of the workpiece is fixed in the axial direction so that diametral reduction and the axial elongation can be studied. Simulations have been carried out at different process conditions to study the state variables, such as stresses and strains obtained during the deformation. The model has been benchmarked with the experimental results for thickness reduction and the error in the thickness prediction is limited to 4%. The roll forces have been benchmarked against analytical formulation and a difference of 13–20% has been observed. The effect of flow forming process variables, such as feed rate and reduction ratio on the stress/strain distribution and roll forces have been studied. The results show that the roll forces increase at higher feed rates and higher reduction ratios whereas the equivalent strains increase at lower feed rates and higher reduction ratios. In addition, a parametric study has been conducted to study ovality, diametral growth, roll forces, stresses and strains as a function of process parameters.
Investigations on Performance of Various Ceramic Tooling While Milling Nickel-Based Superalloy
Authors: Chen Yujie , Milner Justin L. , Bunget Cristina , Mears Laine , Kurfess Thomas R.
Published: November 2013

One of the most cost-effective dimensionally accurate processes used in manufacturing today, that is capable of producing a superior surface finish, is machining. As tooling wears, however, the advantages of machining greatly diminish. In addition, the time lost changing out the tooling significantly affects the overall process efficiency. Therefore, methods that decrease the wear rate of tooling and, thereby, increase tool longevity is essential to improving the efficiency of machining. Optimizing the machining feeds and speeds is one method that has been demonstrated to significantly increase the wear resistance of traditional tooling materials such as HSS, tungsten carbide and advanced ceramic tooling. However, the effects of machining feeds and speeds are not well established for γ′–strengthened nickel-based superalloys. In addition, round geometry inserts were studied due to the rising popularity in industry, since there are an increased number of cutting edges. To help establish these effects, in this work, commercial grade SiAlON (Silicon Aluminium Oxynitride) and Si-WRA (Silicon Carbide Whiskers Reinforced Alumina) cutting inserts are compared. Milling tests were conducted on a γ′–strengthened nickel-based superalloy. More specifically, tool life, machining forces and power were analyzed to evaluate the performance improvements of ceramic tooling. This study found that the abrasive/adhesion flank wear was the main failure mechanism of the ceramic inserts.
Empirical Modeling of Direct Electric Current Effect on Machining Cutting Force
Authors: Jones Elizabeth , Jones Joshua J. , Mears Laine
Published: November 2013

Metallic materials can be made more ductile and be formed at lower forces through the application of electrical current during deformation, termed Electrically-Assisted Forming (EAF). The current provides a degree of resistive heating, but also facilitates deformation by direct electrical mechanisms (termed the electroplastic effect). It is envisioned that this approach, currently applied to bulk/sheet deformation, could also be used to reduce the flow stress in the deformation zone of the machining shear plane. The objective of this work is to study and model the effect of electric current on forces in machining in order to relate the force reduction to the current level and machining process parameters. To perform this, skiving tests and orthogonal machining tests are performed with varying electrical conditions. It is shown that application of electric current does reduce machining force by up to 60% under certain conditions.
Progressive Modeling and the Reconfiguration and Operations Planning Problem
Authors: Ismail Mohamed
Published: November 2013

In this paper, the progressive modeling approach and the Reconfiguration and Operation Planning (ROP) problem are introduced. Progressive Modeling (PM) is a forward-looking multi-disciplinary modeling approach that has been developed to modernize the modeling process of today’s complex industrial problems and create pragmatic solutions for many of them. Many principles and foundations of progressive modeling will be presented while utilizing the reconfiguration and operation planning problem (ROP) as a demonstrating application. The ROP problem describes a new approach of reconfiguration and operations planning in a reconfigurable manufacturing environment. PM is about to spark a new paradigm of solving large-scale system problems in many engineering and business domains in a highly pragmatic way without losing the scientific rigor.
Manual Precedence Mapping and Application of a Novel Precedence Relationship Learning Technique to Real-World Automotive Assembly Line Balancing
Authors: Antani Kavit R. , Pearce Bryan , Kurz Mary E. , Mears Laine , Funk Kilian , Mayorga Maria E.
Published: November 2013

An assembly line is a flow-oriented production system where the productive units performing the operations, referred to as stations, are aligned in a serial manner. The work pieces visit stations successively as they are moved along the line usually by some kind of transportation system, e.g., a conveyor belt. An important decision problem, called Assembly Line Balancing Problem (ALBP), arises and has to be solved when (re-) configuring an assembly line. It consists of distributing the total workload for manufacturing any unit of the product to be assembled among the work stations along the line. The assignment of tasks to stations is constrained by task sequence restrictions which can be expressed in a precedence graph. However, most manufacturers usually do not have precedence graphs or if they do, the information on their precedence graphs is inadequate. As a consequence, the elaborate solution procedures for different versions of ALBP developed by more than 50 years of intensive research are often not applicable in practice. Unfortunately, the known approaches for precedence graph generation are not suitable for the conditions in the automotive industry. Therefore, we describe a detailed application of a new graph generation approach first introduced by Klindworth et al. [1] that is based on learning from past feasible production sequences. This technique forms a sufficient precedence graph that guarantees feasible line balances. Experiments indicate that the proposed procedure is able to approximate the real precedence graph sufficiently well to detect nearly optimal solutions even for a real-world automotive assembly line segment with up to 317 tasks. In particular, it seems to be promising to use interviews with experts in a selective manner by analyzing maximum and minimum graphs to identify still assumed relations that are crucial for the graph’s structure. Thus, the new approach seems to be a major step to close the gap between theoretical line balancing research and practice of assembly line planning.
Ultrasonic Cavitation Peening of Stainless Steel and Nickel Alloy
Authors: Gao Yibo , Wu Benxin , Liu Ze , Zhou Yun
Published: November 2013

Ultrasonic cavitation peening is a peening process utilizing the high pressure induced by ultrasonic cavitation in liquids (typically water). However, the relevant previous investigations in the literature have been limited. In this paper, ultrasonic cavitation peening on stainless steel and nickel alloy has been studied, including the observation or characterization of the surface hardness, morphology, profile, roughness and oxygen contamination of treated workpiece samples. It has been found that for the studied situations, ultrasonic cavitation peening (at a sufficiently high horn vibration amplitude) can obviously enhance the workpiece surface hardness without significantly increasing the surface roughness, changing surface morphology observed by scanning electron microscope (SEM), or contaminating the surface by oxygen.
Paper-Based Lithium Magnesium Oxide Battery
Authors: Aliahmad Nojan , Agarwal Mangilal , Shrestha Sudhir , Varahramyan Kody
Published: November 2013

Replacing of metal current collectors with flexible materials has great potentials of improving flexibility, weight, and applications of Li-ion batteries. This paper presents fabrication and experimental results of lithium magnesium oxide (LiMn2O4) battery using conductive paper current collectors. A thin layer of LiMn2O4 was coated on paper current collectors using air-spray method, and half-cell devices were fabricated. Experimental capacity of 130 mAh/g is reported. The porous structure of cellulous fibers in the current collector improves the adhesion of electrode materials on the substrate, which provides higher flexibility and lighter weight.
Uncertainty Analysis of Tool Wear and Surface Roughness in End Milling
Authors: Sequera A. , Guo Y. B.
Published: November 2013

Tool wear development is an important parameter to control in order to obtain a specific surface integrity in machining operations. Unfortunately, it is difficult to accurately predict the tool life since wear rates generally exhibit a large scattering, and in consequence a scattering in the surface roughness is also present. This paper presents an approach to evaluate uncertainty contributors for tool wear and surface roughness in end milling of superalloy Inconel 718. Multiple regression analysis was applied to develop empirical models of tool wear and surface roughness based on the experimental data. Principles of uncertainty in measurement were applied and uncertainty contributors were identified. It was shown that cutting speed is the principal contributor to the combined uncertainty of tool wear and surface roughness.
Prediction of Mechanical Properties of Microcellular Plastics Using the Variational Asymptotic Method for Unit Cell Homogenization (VAMUCH) Method
Authors: Yu Emily , Turng Lih-Sheng
Published: November 2013

This work presents the application of the micromechanical variational asymptotic method for unit cell homogenization (VAMUCH) with a three-dimensional unit cell (UC) structure and a coupled, macroscale finite element analysis for analyzing and predicting the effective elastic properties of microcellular injection molded plastics. A series of injection molded plastic samples — which included polylactic acid (PLA), polypropylene (PP), polystyrene (PS), and thermoplastic polyurethane (TPU) — with microcellular foamed structures were produced and their mechanical properties were compared with predicted values. The results showed that for most material samples, the numerical prediction was in fairly good agreement with experimental results, which demonstrates the applicability and reliability of VAMUCH in analyzing the mechanical properties of porous materials. The study also found that material characteristics such as brittleness or ductility could influence the predicted results and that the VAMUCH prediction could be improved when the UC structure was more representative of the real composition.
Remote Fiber Laser Processing of Zinc Coated Steels for Automotive Applications
Authors: Colombo Daniele , Previtali Barbara , Masotti Giovanni
Published: November 2013

The flexibility in terms of beam shapability and amplitude in the process parameters range offered by the emerging high power and quality active fiber lasers can be advantageously used in overcoming the well known problems in remote laser welding of zinc coated steel components in the car mass production. The paper explores the potentiality offered by an ad hoc scanner head realized for remote laser welding, making use of high power and high quality fiber laser beams. In particular the substitution of the traditional mechanical dimpling with the laser dimpling is investigated, state of art remote laser welding joints are obtained, and the laser wobbling technique is explored in order to increase the bead quality.
Empirical Demonstration of Acausal Control Strategies for Wave Energy Converters
Authors: Eder James , Bretl James , Edwards Kathleen
Published: November 2013

The benefit of acausal control strategies for Wave Energy Convertors (WECs) is empirically demonstrated in a wave tank. An upstream wave gage is used to provide real time predictions of the wave elevation at the WEC’s location. Using a sub-optimal control strategy based upon complex conjugate control, these predictions are used to generate real time force commands for the Power Take Off (PTO) system. Empirical comparisons are made between the acausal control strategy and a simple linear damping approach.
A Parametric Model for Tropical Cyclone Waves
Authors: Young I. R. , Vinoth J.
Published: November 2013

One of the major challenges in fully understanding the complex wave fields produced by intense tropical cyclones is having sufficient data to fully define the spatial wave field in such systems. Although the in situ data set is increasing, it is still quite limited and does not cover the full range of possible tropical cyclone parameters. One way to address this problem is to use remote sensing data obtained from satellites. Radar altimeters on such satellites have now been in operation for more than 25 years. Such a data set is used to investigate the wave field within tropical cyclones. The full data set consists of the over flight by an altimeter of a total of 440 tropical cyclones. As such, the data set is the most extensive ever obtained under tropical cyclone conditions. Using this data set, a parametric model for the wave field is developed. The analysis confirms that the most extreme waves are generated to the right (northern hemisphere) of the storm, where the waves generated tend to move forward with the storm. As such, they experience an extended fetch. This concept is used in conjunction with JONSWAP scaling to develop a parametric model which can be used to predict the tropical cyclone wave field. This model is then used in conjunction with in situ data to provide an estimate of the wave spectrum at any point in the spatial wave field. This approach provides a very valuable approach for preliminary design and extreme value studies.
Time Series Analysis of Significant Wave Height Data for Identification of Trends in the Ocean Wave Climate
Authors: Vanem Erik , Walker Sam-Erik
Published: November 2013

Reliable return period estimates of sea state parameters such as the significant wave height is of great importance in marine structural design and ocean engineering. Hence, time series of significant wave height have been extensively studied in recent years. However, with the possibility of an ongoing change in the global climate, this might influence the ocean wave climate as well and it would be of great interest to analyze long time series to see if any long-term trends can be detected.

In this paper, long time series of significant wave height stemming from the ERA-40 reanalysis project, containing 6-hourly data over a period of more than 44 years are investigated with the purpose of identifying long term trends. Different time series analysis methods are employed, i.e. seasonal ARIMA, multiple linear regression, the Theil-Sen estimator and generalized additive models, and the results are discussed. These results are then compared to previous studies; in particular results are compared to a recent study where a spatio-temporal stochastic model was applied to the same data. However, in the current analysis, the spatial dimension has been reduced and spatial minima, mean and maxima have been analysed for temporal trends.

Overall, increasing trends in the wave climate have been identified by most of the modelling approaches explored in the paper, although some of the trends are not statistically significant at the 95% level. Based on the results presented in this paper, it may be argued that there is evidence of a roughening trend in the recent ocean wave climate, and more detailed analyses of individual months and seasons indicate that these trends might be mostly due to trends during the winter months.