bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of Gas Transportation in Radial Shaft Seal With Model Surfaces
Authors: Mizuta H. , Nakaoka S. , Sato Y. , Sugimura J.
Published: April 2011

This paper describes an analytical study on gas transportation in radial shaft seal. A model is constructed in which seal surfaces with sinusoidal roughness, lubricant flow at the seal lip with gaseous cavity, dissolution of gas into and release of gas from the lubricant across double boundary films at gas-liquid interfaces, and convection of dissolved gas in the lubricant flow are considered. Polyalphaolefin as a lubricant, and helium, argon and carbon dioxide are assumed. The results demonstrate that the axial flow induced by surface roughness carries the gas, and that the gas flow through the lubricant film is proportional to the gas solubility coefficient, and the circumferential speed of the shaft, which agrees with the experimental finding for actual seals. The dependence of the gas flow on the axial flow of the oil and that on the boundary films are discussed.
Simulation of Wet Clutch Engagement on Electronically-Controlled Limited-Slip Differential (LSD) With Consideration of Degraded Clutch Performance
Authors: Choi Jaewon , Nakhaeinejad Mohsen , Bryant Michael D.
Published: April 2011

A wet clutch is an integral part of the electronically controlled limited slip differential (eLSD) [1]. In this study, an eLSD model is constructed based on Deur et al.’s dynamic wet clutch model [2]. First the eLSD model including key dynamic equations and parameter values is discussed. The main culprits of clutch shudder include the negative slope of friction coefficient vs. slip speed curve, which is often caused by oil oxidation due to heat or an improper amount of friction modifier among others, and glazing of the friction linings [3,4]. In the second part, consequences of improper lubrication and glazed friction material during launch control of a vehicle equipped with eLSD will be studied based on simulations with lubrication data provided in [3]. The simulation results show that the combined effects of oxidized ATF and glazed friction material can cause clutch shudder.
The Film Formation Mechanism of High Water-Based Emulsions
Authors: Luo Jianbin , Ma Liran
Published: April 2011

The oil-in-water emulsion has been widely used as lubricant in metal working such as metal rolling and cutting. The film formation ability of emulsion was considered as an important factor for evaluating the lubricating effectiveness. Although the film formation characteristics have been widely investigated, the mechanism is still not well understood. Furthermore there were seldom results reported on the emulsion with an oil volume percentage less than 1%. The film formation characteristic of emulsions with ultra-low oil concentration (0.005vol%) between a smooth plate and a highly polished steel ball was investigated. The effects of oil concentration and emulsifier concentration were investigated. New viewpoints on the film formation mechanism of emulsion were proposed.
Response of Metals and Polymers During Sliding: Role of Surface Texture
Authors: Menezes Pradeep L. , Kishore  , Kailas Satish V. , Lovell Michael R.
Published: April 2011

Surface texture influences friction during sliding. In the present investigation, experiments were conducted using an inclined pin-on-plate apparatus to study the tribological response of metals and polymers during sliding against various surface textures. In the experiments, metals (Pb and Sn) and polymers (PP and PVC) were used for the pin and hardened steel was used for the plate. Experiments were conducted under both dry and lubricated conditions in an ambient environment. Two surface parameters of the steel plates — roughness and texture — were varied in the experiments. Using scanning electron microscope images, the surfaces of both the plate and pin materials were examined to determine the transfer layer formation on the plate and the wear of the pins. Based on the experimental results, it was observed that the transfer layer formation and the coefficient of friction were controlled by the surface texture of the plates. Moreover, both polymers and metals exhibited similar frictional responses, but the metals had a significantly larger variation in friction with surface texture.
Tribo-Electric Behaviors of Copper Under Dry Sliding Against Cu-Cr Alloys
Authors: Shangguan Bao , Zhang Yongzhen , Xing Jiandong
Published: April 2011

The tribological and electrical conduction behaviors of copper under dry sliding against copper-chromium alloys were investigated on the basis of simulation tests. The experimental results show that electrical current and trbological parameters have combined effects on both electrical conduction ability and trological properties. High sliding velocity and electrical current density deteriorate both the tribological and electrical conduction properties in tribo-electrical sliding system. In the end, Worn surface analysis suggests frictional and electrical resistance heating, electrical arc spoiling are the main factors to influence the tribological and electrical conduction properties.
A New Mechanism for Squealing Noise and Friction-Induced Vibrations in the Railway Industry
Authors: Chen G. X. , Zhou Z. R.
Published: April 2011

In the paper, a new mechanism for squealing vibration based on the time delay concept of friction is introduced. Firstly, several test results on the time delay between the varying normal force and the consequent varying friction are presented and discussed. Secondly, the motion stability of a friction system with the time delay is analyzed in theory. The result shows that the friction system may become unstable in the presence of the time delay. Thirdly, the advantages and disadvantage of the new mechanism are discussed. The remaining part of the paper will present several research advances in the application of friction-induced vibration theory in the railway industry. In the authors’ work, a finite element model of friction self-excited vibration of a railway wheelset-track system is established. The motion stability of the model is analyzed. Numerical results show that friction between the wheel and rail easily causes self-excited vibration of a railway wheelset-track system. The relation between the rail corrugation and friction-induced vibration is discussed. Finally, the field test results in Subway line 4 of Beijing are presented. The test results show that there exists self-excited vibration of a railway wheelset-track system when vehicles negotiate sharp curved tracks.
Local Wear Models That Sometimes Work: Isothermal Sliding
Authors: Soom Andres , Stenz Nathaniel , Dargush Gary
Published: April 2011

We present some local wear calculations that compare the Standard pressure-based local wear model with a newer one (DSS) that includes von Mises stresses. The DSS model predicts the conforming wear tracks that one often finds at real contacts but cannot be predicted by the Standard approach. However, we find that the newer method, while giving conforming wear track shapes, can predict different amounts of global wear when identical materials in conformal contact are slid against one another. This is not found in experimental studies of a nominally similar system. We conclude that no universally local wear modeling approach exists and the present time.
Debris Contamination in Sliding Contacts
Authors: Kyle Jonathan P. , Terrell Elon J.
Published: April 2011

Particulate contaminated lubricants can be detrimental to any tribosystem. Debris can originate from the external environment, be unintentionally introduced during fabrication, or be generated internally during operation. These particles, if not carefully filtered out, can have serious implications on the integrity of a tribosystem. This study focused on the abrasive wear observed from four-ball wear tests in the presence of lubricant with particulate contaminants. The contaminants studied were silicon dioxide sand particles and self generated AISI E-52100 steel particles. The particles were submerged in an industrial EP gear oil. The effects of particle size, composition, and concentration on abrasive wear of sliding interfaces was analyzed.
Hot Forming Technique and Its Equipments for Ultra High Strength Steel
Authors: Ma Ning , Hu Ping
Published: April 2011

Hot forming of ultra high strength steel is an advanced forming technique which can not only represent the best solution to increasing the strength-to-mass ratio of sheet components, but also meet the need of higher passive safety and weight reduction. Based on independently developed mass production line of hot forming, its key forming and quenching technique and relative equipments are proposed and described, including multi-step and one-step method, die manufacturing with cooling system, continuous heating furnace and integrated manufacturing system composed of the advanced interdisciplinary technology of machining, electronic control, material and chemical engineering. Then the automobile body components are produced by the developed equipments of hot forming and moreover their mechanical properties are investigated. The typical tensile curve of the quenched components shows that the yield stress of the hot forming component is over 1000MPa, and the strength limitation is over 1600MPa. The three-point bending testing of the part is implemented. These experimental results indicate the validity of the developed technique and equipments.
Combining Process Dynamics and Tool Wear in the Milling Super Diagram
Authors: Karandikar Jaydeep , Zapata Raul , Schmitz Tony L.
Published: April 2011

This paper describes the milling “super diagram” that incorporates limitations to milling productivity and part quality imposed by stability, surface location error (part errors due to forced vibrations), and tool wear. Combinations of axial depth of cut and spindle speed that offer stable cutting conditions with an acceptable, user-defined surface location error level are identified by a gray-scale color coding scheme. The effect of tool wear is included through the force model coefficients (that relate the cutting force to the chip area) used for process dynamics prediction. Because the force model coefficients vary as a function of the volume of material removed, a unique super diagram is constructed for any user-defined volume of material removed with the selected cutter. For example, preferred operating conditions for a new tool can be compared to those for a worn tool. Additionally, user beliefs about data and model accuracy are applied to identify safety margins relative to the deterministic boundaries in the diagrams. Experimental results are provided for an inserted (carbide) cutter used to machine 1018 steel. The wear behavior is characterized as changes in the force model coefficients as a function of the volume of material removed. The flank wear is also measured using an on-machine microscope (to avoid tool removal from the spindle) and correlated to the force model coefficients. Stability diagrams are developed that correspond to the new and worn tool performance and experimental results are provided to verify changes in the process stability due to tool wear.
Smart Machining Simulation Based on High-Level Data
Authors: Abdul Kadir Aini Zuhra , Xu Xun
Published: April 2011

The main objective of any machining simulation system is to produce a model that can reveal or mimic the real machining process as accurately as possible. Current simulation systems often use G-code or CL data as input that has inherent drawbacks such as vendor-specific nature, incomplete data, irreversible data conversions and lack of accuracy. These limitations hinder the development of a ‘trustworthy’ simulation system. Hence, there is a need for higher-level input data that can assist with accurate simulation for machining processes. There is also a need to take into account of true behaviour and real-time data of a machine tool. The paper presents a ‘near-real simulation’ solution for more accurate results. STEP-NC is used as the input data as it provides a more complete data model for machining simulations. Data from the machine tool is captured by means of sensors to provide true values for machining simulation purposes. The outcome of the research provides a smart and better informed simulation environment. The paper reviewed some of the current simulation approaches, discussed input data sources for smart simulation system and proposed near-real simulation system architecture.
Deformation Analysis of Multi-Stage Incremental Sheet Forming
Authors: Cui Zhen , Ren Feng , Xia Z. Cedric , Gao Lin
Published: April 2011

This paper presents an analytical and numerical study of deformation analysis for multistage incremental sheet forming processes, with a truncated conical part is used as an example. Unlike in the single-pass incremental forming where the sheet deformation is dominantly plane strain in the axial direction when forming a conical part, the sheet is also deformed in the circumferential direction when it is incrementally formed subsequently. Ideal deformation kinetics is assumed in the analytical derivations of strain distributions, which should be valid as long as the increment in deformation from one stage to the next is small. Numerical simulations with LS-DYNA are also conducted in an effort to understand the fundamental deformation mechanics of multistage incremental forming. The simulation result for a five-stage incremental forming process is presented. It is also used to correlate the analytical solution. An improved analytical equation for strain distributions is derived, which compares favorably with simulation results.
Springback in Sheet Metal Forming of Stainless Steel 410
Authors: Ragai Ihab , Nemes James A.
Published: April 2011

This paper considers the use of finite element simulation of sheet metal forming as a tool to evaluate geometrical defects caused by elastic springback. The simulations aim to provide reliable information about the deviation of the real part geometry from that defined in the design phase in order to overcome the subsequent assembly problems. The material studied and presented in this paper is stainless steel 410. In order to determine the material properties and the parameters needed for the simulations, a series of experiments including uniaxial and cyclic tests were carried out. Moreover, bending experiments were conducted so that simulation results can be verified against simple forming operations. To expand the use of the model to predict the effect of forming parameters on springback, an aircraft engine cone-shaped component was simulated and the results were compared to the actual formed part. Predictions of the final shape and thickness variation were successfully obtained and were in agreement with the cone forming experiments.
Pose Estimation and Force Prediction of Non-Rigid Endoscopic Tool
Authors: Lei Yang , Miller Scott
Published: April 2011

Endoscopy is useful for inspecting features in hard-to-reach cavities, such as the blades inside a turbine engine with a flexible body and a semi-rigid bending section. It is hypothesized that an endoscope can be used to grind a predetermined amount of material to smooth the cracks on turbine blades in those cavities. By turning control knobs on the endoscope, the bending section can access a workpiece on its lateral direction. In this research, two models are built to estimate the pose (position and orientation) and force on a modified PENTAX ES-3801 endoscope. The experimental and estimated results prove that the pose and force of the flexible bending section can be predicted and monitored when subjected to varying loads.
Investigation on Sheet Hydroforming Process of Titanium/Aluminum Clad Metal Housing
Authors: Tseng Huang-Chi , Wu Zong-Chun , Hung Chinghua , Lee Ming-Hu
Published: April 2011

In this research, the sheet hydroforming process (SHF) was adopted to form a Ti/Al clad metal housing with complex shape. Nowadays, SHF has been widely accepted for the production of components characterized by high surface quality, precise dimensional accuracy together with high drawing ratio. For investigating the formability of the Ti/Al clad metal housing through SHF, the concept of virtual film were developed with explicit finite element method. First, the simulation model was verified by comparing the deformation of the blank obtained from experiments. Through finite element simulations, several significant process parameters such as holding force, tooling geometry, blank dimensions, single-stage (with pre-bulging effect) and multi-stages SHF were analyzed for improving formability of the Ti / Al clad metal housing during SHF.
A Sequential Greedy Search Algorithm With Bayesian Updating for Testing in High-Speed Milling Operations
Authors: Traverso Mike , Zapata Raul , Karandikar Jaydeep , Schmitz Tony L. , Abbas Ali
Published: April 2011

This paper describes a probabilistic greedy search optimization algorithm for stability testing in high-speed milling. The test parameters (i.e., the experiment setup decisions) consist of the axial depth of cut and the spindle speed. These parameters are selected to maximize the expected value of profit using a greedy search approach (an approach that maximizes the expected value of each stage one step at a time). After a test is performed, Bayesian updating is applied to determine the posterior distribution of stability. The algorithm is then repeated to identify a new test point. The motivation for this work is that, while deterministic models for milling stability prediction are available, uncertainty in the inputs always exists. In this study, it is assumed that the tool point frequency response function, which is required for stability lobe diagram development, is unknown. Therefore, the probability of stability over the selected axial depth-spindle speed domain must be determined experimentally. The greedy search algorithm identifies the maximum expected value of profit within the selected domain, where profit is determined from the product of the profit function and the stability cumulative distribution function, referred to as the probability of stability. This optimal point is then tested to evaluate stability. Whether stable or unstable, the results are used to update the probability of stability. A stable test updates all axial depths smaller than test depth to be stable at the selected spindle speed, while an unstable test specifies that all axial depths above the test depth are unstable. After updating, a new test point is selected by the greedy search algorithm and the process is repeated. This select/test/update sequence is repeated until a preselected stopping criterion is reached. This paper presents both numerical results and experimental validation that the optimization/updating approach quickly converges to the well-known stability lobe behavior described in the literature. However, in this probabilistic technique the issue of uncertainty is also addressed and results can be obtained even if no information about the dynamic system is available.
An Integrated Approach to Spot Welding Sequence Planning and Optimization
Authors: Givehchi Mohammad , Ng Amos , Wang Lihui
Published: April 2011

Almost in every discipline involved in Product and Production Development (PPD), optimization problems arrive. These real-world problems are too complex to be solved by analytical models and classical optimization methods. CAx and Virtual Manufacturing (VM) tools are on the other hand being employed more and more to create virtual representation models of the products under development and their related production facilities, processes, and systems in a virtual environment before any physical realization is conducted. Synergy of these two domains is of interest in this paper where a PPD problem requiring planning a process with the minimum cycle-time for assembling a spot welded sheet-metal product was solved. The methodology suggests an extendible virtual manufacturing-based optimization approach using evolutionary algorithms. The methodology is also required to be partially compliant to the concept of integrated Product-Process-Resource planning and optimization. An optimization tool is developed accordingly for operation sequence optimization integrated with a commercial VM environment.
Curing and Consolidation of Advanced Thermoset Composite Laminate Parts by Pressing Between a Heated Mold and Customized Rubber-Faced Mold
Authors: Walczyk Daniel , Kuppers Jaron , Hoffman Casey
Published: April 2011

Curing and consolidating thermoset composite laminates and sandwich structures typically involves vacuum bagging an uncured and formed layup over a thin-walled mold, placing it in an autoclave, and subjecting the entire unit to temperature, vacuum and pressure cycles as prescribed by the manufacturer. Autoclaving is generally considered the major bottleneck in manufacturing of advanced composites parts because of high capital and consumable costs, energy usage, waste generated and process scalability. A new curing and consolidation process, called ‘thermal press curing’ is discussed and demonstrated as an alternative to autoclaving. The process involves compressing a composite laminate between a special mold set — heated metal mold and a matching rubber-covered mold made of an insulative material — designed to provide uniform temperature and pressure over the metal mold surface, that is, mimic the process conditions provided by an autoclave. The thermal press curing process is demonstrated for the first time using a mold set for a simple 2-dimensional axisymmetric shape. An aluminum curing mold with embedded electric resistance cartridge heaters is heuristically designed to provide uniform temperature in operation across the mold surface within 1°C of the target value (177°C). With the mold set compressing an eight-ply carbon/epoxy composite workpiece and well insulated on all sides, the power draw is at least 1–2 orders-of-magnitude less than a comparable autoclaving operation. The potential to significantly improve pressure uniformity from the compressed rubber mask is shown by changing the mask shape. Even without an optimized rubber layer shape and thickness, the eight-ply composite part was successfully cured. Finally, a plan for future work is described.
Identification for Control of Low Pressure Die Casting
Authors: Shi XinMei , Maijer Daan M. , Dumont Guy
Published: April 2011

Controlling and eliminating defects, such as macro-porosity, in die casting processes is an on-going challenge for manufacturers. Current strategies for eliminating defects focus on the execution of a pre-set casting cycle, die structure design or the combination of both. To respond to process variability and mitigate its negative effects, advanced process control methodologies may be employed to dynamically adjust the operational parameters of the process. In this work, a finite element heat transfer model, validated by comparison with experimental data, has been developed to predict the evolution of temperatures and the volume of liquid encapsulation in an experimental casting process. A virtual process, made up of the heat transfer model and a wrapper script for communication, has been employed to simulate the continuous operation of the real process. A stochastic state-space model, based on data from measurements and the virtual process, has been developed to provide a reliable representation of this virtual process. The parameters of the deterministic portion result from system identification of the virtual process, whereas the parameters of the stochastic portion arise from the analysis and comparison of measurement data with virtual process data. The resulting state-space model, which can be extended to a multi-input multi-output model, will facilitate the design of a model-based controller for this process.
Dry Turning of Commercially Pure Aluminium With Carbide Tools
Authors: Wang Xin , Kwon Patrick
Published: April 2011

Dry turning test was performed on commercial pure aluminum Al1100 with two grades of carbide (WC-Co) tool, fine and coarse grained grades. Because of the tiny amount of abrasives in Al1100, the resulting tool wear is mainly sliding wear on flank surface. In our experiment, the fine grain carbide tool has more wear than coarse grain carbide tool despite of the miniscule wear on both carbide grades tools. Notably, the microfracture was only observed on the fine grain carbide tool’s nose due to the low fracture resistance of fine grain carbide. Using Confocal Laser Scanning Microscopy (CLSM) and wavelet filtering, the built up edge (BUE) and tool wear evolutions were analyzed. The volume of BUE becomes the maximum at the beginning of the machining and diminishes as the cobalt was worn down from the tool surface, eventually reaching a relatively steady state after half hour’s turning. The fine grain carbide tool have more built up edge than coarse grain carbide tool because of the higher cobalt content with the fine grain carbide. Oxygen from the air may play a very important role in the adhesion between aluminum and carbide tool. Two types of built up edge was found in the experiment. The first type BUE is huge and covers whole tool surface, which is mainly aluminum. The second type BUE is very thin (∼1–2microns), which covers relatively small area of tool surface. This location is characterized by both high temperature and the presence of the oxygen from the air trapped between tool and work material. This second type of BUE has much better resistance to the NaOH solution, which is metal oxide (Aluminum oxide or complex oxide such as spinel), and it could increase the adhesion between tool and work material. Mainly, in dry turning commercial pure aluminum, the larger carbide grain size has a better wear performance.
Predicting the Effects of Rake Angle, Cutting Speed and Feed Rate on Chip Morphology in Hard Turning
Authors: Wu Shenfeng , Zhang Xueping , Liu C. Richard
Published: April 2011

This paper proposes a thermo-mechanical orthogonal cutting finite element model (FEM) to investigate the variation of chip morphology from continuous chip to small and large saw-tooth chip. The corresponding experiments of hard turning AISI 52100 steel are conducted to validate the proposed FE model. Three one-factor simulation experiments are conducted to determine the evolution of chip morphology along feed rate, rake angle and cutting speed respectively. The chip morphology evolution is described by the variations of dimensional values, saw-tooth degree and chip segmental frequency. The research suggests that chip morphology transit from continuous to sawtooth chip with increasing the feed rate and cutting speed, and changing a positive rake angle to a negative rake angle. There exists a critical cutting speed at which the chip morphology transfers from continuous to saw-tooth chips. The saw-tooth chip segmental frequency decreases as the feed rate and negative rake angle value increase, but increases almost linearly with the cutting speed. The larger negative rake angle, the larger feed rate and high cutting speed dominate the sawtooth chip morphology while positive rake angle, small feed rate and low cutting speed determine continuous chip morphology.
On Predicting Residual Stress and Chip Morphology in Pre-Stressed Hard Turning
Authors: Wang Heping , Wu Shenfeng , Zhang Xueping , Liu C. Richard
Published: April 2011

To analyze AISI 52100 steel response in hard turning under pre-stressed conditions, an explicit dynamic thermo-mechanical finite element model (FEM) has been developed. The FEM adopts Johnson-Cook constitutive model to describe the workpiece material property; and Johnson-Cook failure model as chip separation criterion; a modified coulomb’s friction law determines the friction behavior at the tool/chip interface. 500MPa of tensile and compressive pre-stress are imposed on the workpiece to simulate the pre-tension-stress and pre-compression-stress conditions respectively in hard turning. The effect of pre-stress on hard turning is determined by analyzing and comparing the simulation results under the three different pr-stress conditions, in terms of saw-tooth chip morphology, cutting forces, plastic strain distribution and temperature distribution on chip, plastic strain distribution and temperature distribution in machined surface, and especially the residual stress in machined surface. It identifies hard cutting under pretension-stress condition is an effective approach to generate a beneficial compressive residual stress profile in hard turning characterized by a bigger value of compressive residual stress and a deeper penetration depth into the hard turned surface which are helpful to enhance the fatigue life of machined components.
Product and Process Characteristics for Green Manufacturing: Evidence From Indian SMEs
Authors: Singh Perminderjit , Sangwan K. S.
Published: April 2011

With growing awareness of environmental issues — from global warming to local waste disposal — business and government have come under increasing pressure to reduce the environmental impacts involved in the production and consumption of goods and services. However, organizations consider environmental assessment fairly late in the product development process, which generates additional design constraints and increases the development costs. The integration of environmental requirements through life-cycle stages of a product is a likely approach, leading to a new paradigm of green manufacturing. Empirical studies by various authors have indicated that Small and Medium Enterprises (SMEs) find it difficult to implement environmental issues in product and process design because of lack of time, resources, expertise and/or framework in comparison to large enterprises. This paper presents the results of an empirical study carried out on Indian SMEs to develop product and process characteristics of green manufacturing. Fifteen product and four process characteristics have been developed to be considered during the product and process design to address the environmental issues for the life cycle of the product. These characteristics provide an easy to use self assessment framework to the SMEs to address the various environmental issues during the product and process design. The characteristics identified from the literature have been validated by using SPSS for Windows statistical tool. The reliability and validity of the data has been assessed by the Cronbach alpha and factor analysis respectively. The results provide sure evidence that the developed characteristics are highly reliable having Cronbach alpha values more than 0.9. Factor loading values for all characteristics are above 0.6, which shows the high validity of the data. A high value of Pearson correlation coefficients also reflects the high correlation among the developed characteristics. The study highlights the various environmental issues to be considered by the SMEs during the product design and development phase.
Effects of Particle Size on Cellulosic Biomass Pellets: A Literature Review
Authors: Zhang Q. , Zhang P. F. , Pei Z. J.
Published: April 2011

Cellulosic biofuels are becoming an attractive alternative to conventional liquid transportation fuels. Cellulosic biomass is the feedstock for cellulosic biofuel manufacturing. However, high transportation and storage cost of cellulosic biomass due to its low density hinders large-scale and cost-effective manufacturing of cellulosic biofuels. Pelleting processes are used to produce biomass pellets which have higher density and are easier to handle in transportation and storage. Before going through pelleting processes, original cellulosic biomass materials are milled into particles. The particle size is an important input parameter in pelleting processes. Many investigations have been conducted on effects of biomass particle size on pellet quality (in terms of density, durability, stability, and strength). This paper reviews the literature about effects of particle size on pellet quality. Investigated biomass materials, selected range of particle size, utilized milling and pelleting processes are summarized. The approaches to evaluating pellet quality are also reviewed.
Microstructural Study on Strain Induced Transformation in Austempered Ductile Iron Using Heat Tinting
Authors: Polishetty Ashwin , Pan Bing Bill , Pasang Timotius , Littlefair Guy
Published: April 2011

This work is an experimental study on effect of microstructural change due to Strain Induced Transformation (SIT) of Austempered Ductile Iron (ADI) by heat tinting and corroborates the result with SIT related to machining of ADI. On machining ADI, the microstructure changes rapidly from austenite to martensite due to SIT. The analogy between SIT and machining is addressed in this paper. Evaluation to quantify the likely extent of SIT during machining of grades 900, 1050, 1200 and 1400 via heat tinting of plastically deformed samples has been conducted. Heat tinting causes coloration of the etched specimen, distinguishing each microstructural phase. The initial results appear to indicate the occurrence of SIT on all grades of ADI. SIT can be excessively seen on Grade 1400.
Non-Contact Surface Roughness Measurement for Remote Quality Control
Authors: Chiou Richard Y. , Kwon Yongjin James , Yang Yueh-Ting , Kizirian Robin , Tseng Tzu-Liang Bill
Published: April 2011

This paper presents a new method of surface roughness measurement developed for use in a web-enabled production environment. This method employs an Internet-based vision system to measure and analyze the pattern of scattered light from a surface of an object to derive roughness parameters. The roughness parameters are obtained for a number of metal specimens which are machined to different roughnesses. A correlation curve is established between optical intensity and the corresponding average surface roughness. The quality measurement data is monitored through the web browser while surface roughness parameters are inspected using a machine vision system. This allows the system to operate over the Internet since the machine vision system is integrated with LabVIEW-based graphic user interface (GUI).
Effects of Air Flow, Draw Temperature and Boundary Conditions on Hardening in Ice Cream Manufacturing
Authors: Rauth N. L. , Miller Mark J. , Xin X. Jack , Pei Z. J. , Schmidt Karen A.
Published: April 2011

Energy consumption by the dairy food industry in the United States constitutes 10% of all energy consumed by the U.S. food industry, and reducing energy consumption in cooling and refrigeration of foods plays an important role in meeting the challenge of the energy crisis. Hardening is an important and energy-intensive step in ice cream manufacturing. This work presents Finite Element Method (FEM) investigation of the hardening process in ice cream manufacturing and assesses the accuracy and acceptability of the presented FEM methods. The FEM results are compared to experimentally data from the literature, and sources of variation including convection coefficient, bottom surface boundary condition and draw temperature are explored.
Experimental Investigation of Coefficient of Friction During the Friction Stir Processing of Aluminum
Authors: Miller Scott , Arnold Lee , Kruger Grant
Published: April 2011

There is a lack in understanding of the frictional contact condition during friction stir processes. High temperature, force and work material adhesion to and from the tool make the coefficient of friction difficult to measure. In this study, an experiment was set up to simultaneously measure the temperature and normal and frictional forces between a rotating tool and a stationary workpiece at steady state conditions. The coefficient of friction was measured for increasing temperature. A simple model was created to convert the thermocouple temperature measurement to the temperature at the point of contact between the tool and workpiece. It was found that the coefficient of friction had a decreasing trend as temperature approached the solidus temperature of the work material. The results and analysis of the experiments are presented.
The Plasma-Side Wall Interactions During Femtosecond Laser Drilling of High-Aspect-Ratio Microholes
Authors: Wu Benxin , Tao Sha , Lei Shuting
Published: April 2011

The drilling of high-aspect-ratio microholes has very important applications in automotive, aerospace, electronics and other areas. However, this is difficult to realize with conventional mechanical machining or electrical discharge machining approaches. Femtosecond laser ablation can potentially provide a good solution to this, but it also involves many technical difficulties. One of these is that the laser-induced plasma, as it expands out of the microhole, may transfer its energy to the side wall of the hole, which may affect the hole size and geometry. In this paper, the plasma – side wall interaction has been studied using a physics-based model, and the discovered characteristics of the interaction are discussed.
Nanosecond Laser Ablation of Silicon Carbide at Infrared Wavelength
Authors: Gao Yibo , Zhou Yun , Wu Benxin
Published: April 2011

Silicon carbide, due to its unique properties, has many promising applications in optics, electronics and other areas. However, it is difficult to process using mechanical machining or electrical discharge machining due to its electrical insulation, high hardness and brittleness. Laser ablation can potentially provide a good solution for silicon carbide micromachining. However, the study on silicon carbide ablation by nanosecond laser pulses at infrared wavelength is limited, and will be presented in this paper. The laser ablation rate, laser-induced plasma, the ablated surface morphology and chemical composition change have been studied, and the results are discussed.
Die Design and Axial Feeding in the Tube-Hydroforming Process
Authors: Lin Sin-Liang , Chen Fuh-Kuo
Published: April 2011

In the present study, the loading path with constant internal fluid pressure during axial feeding to hydroform an automotive structural part with higher expansion ratio was investigated. The axial feedings employed at various internal fluid pressures were simulated by the finite element method. It is found that the axial feeding applied at a favorable internal fluid pressure, the production part with higher expansion ratio still could be made. Compared with other loading paths published in literature, which are mainly linear paths, the proposed loading path provides a simple approach to achieve better performance in the hydroforming process. The factors causing wrinkling fin the hydroforming process were also studied by analyzing the relationship between the die face shape and the material flow in the die cavity. An optimum die face design that avoided pinching at the die closing process was then proposed. The actual hydroforming process for manufacturing the automotive structural part was conducted as well in the present study to validate the proposed loading path and the optimum die face design. The consistent agreement between the production part and the finite element simulation results confirms not only the proposed loading path and die face design, but also the effectiveness of the finite element analysis employed in the tube-hydroforming process.
Benchmarking of High Capacity Battery Module/Pack Design for Automatic Assembly System
Authors: Li Sha , Wang Hui , Lin Yhu-tin , Abell Jeffrey , Hu S. Jack
Published: April 2011

Electric vehicles (EV), including plug-in hybrid and extend-range EVs, rely on high power and high capacity batteries, such as lithium-ion batteries, as the main source of propulsion energy. The EV battery technology is progressing rapidly as a plurality of battery designs in cells, modules and packs are emerging on the market. Current EV battery pack assembly is mostly manual and has faced significant challenges in coping with such fast development of automotive batteries. Meanwhile, there is a lack of systematic study on the implications of varieties in battery designs on assembly system. This paper reviews various battery module or pack designs and characterizes them from the assembly process perspective, and discusses their implications with respect to assembly methods, process flexibility and automation feasibility. The associated cost, quality, and safety issues of assembly are also addressed and research opportunities and innovations are discussed. This study can assist in creating guidelines on the development of new generations of battery products that enables highly efficient and responsive battery assembly.
Magnetic Field Assisted Finishing of Silicon MEMS Micro-Pore X-Ray Optics
Authors: Riveros Raul E. , Yamaguchi Hitomi , Boggs Taylor , Mitsuishi Ikuyuki , Mitsuda Kazuhisa , Takagi Utako , Ezoe Yuichiro , Ishizu Kensuke , Moriyama Teppei
Published: April 2011

An alternating magnetic field assisted finishing (MAF) technique has been developed to finish the 5–20 μm wide pore sidewalls of micro-pore X-ray focusing optics fabricated using micro-electro-mechanical systems (MEMS) techniques. To understand the material removal mechanism, this MAF technique is used to finish a silicon MEMS micro-pore X-ray optic that had previously undergone a hydrogen annealing treatment. Compared to the unfinished surface, distinctive surface features are observed on the finished surfaces using scanning electron microscopy, optical profilometry, and atomic force microscopy. This demonstrates the finishing characteristics and reveals the material removal mechanism on the nanometer scale. Moreover, the representative unfinished and finished micro-pore sidewall surfaces show a reduction in roughness due to finishing from 1.72 to 0.18 nm Rq.
Reproduction of Lustrous Object and Cutter Location Using the Normal Vector Generated by Photometric Stereo Method
Authors: Nakamura Seishi , Hirogaki Toshiki , Aoyama Eiichi , Nobe Hiromichi
Published: April 2011

In the present study, the shape of an object is first obtained from photographic images using the photometric stereo method, and then the target object is created using material that gives an artificial impression of wood. We found through experimentation that the output gradient on the surface of the target object is limited to 67°. Moreover, there is a fault that a lustrous object cannot be reproduced by a general photometric stereo method. Then, to overcome the fault, we propose using a Gaussian filter. The results showed that the maximum error margin of the shape of the reproduced object could be adjusted from 8.3 to 3.3%. At the end, the feature that the normal vector in respect is obtained by using the photometric stereo method is made the best use of, and we propose a new method to obtain cutting location (CL) data for ball-end milling using the normal vector of the object geometries generated by the photometric stereo method. As a result, the tool path was quickly and easily derived, without the use of CAD data.
Predicting the Effects of Tool Nose Radius and Lead Angle on Hard Turning Process Using 3D Finite Element Method
Authors: Zhang Xueping , Wang Heping , Liu C. Richard
Published: April 2011

Finite element method (FEM) has been qualified as an excellent method to analyze machining processes. Many researchers commonly adopt an orthogonal FE model to simulate hard turning process without considering the effect of tool nose radius and/or lead angle. However, the PCBN cutting tools usually possess a nose radius of 0.4mm to 0.8mm, which equals to the magnitude of cutting depth/feed in hard turning. To explore the effect of tool nose radius and rake angle on hard turning AISI 52100 steel process, an explicit dynamic thermo-mechanical three-dimensional (3D) FEM is developed. The model considers tool nose radius as 0.4mm and 0.8mm, respectively with a tool lead angle of 0° and 7°. The model successfully simulates 3D saw-tooth chip morphology generated by periodic adiabatic shear and demonstrates the continuous and saw-tooth chip morphology, chip characteristic line and the material flow direction between the chip-tool interfaces. The predicted chip morphology, cutting temperature, plastic strain distribution and cutting forces agrees well with the experimental data. The oblique cutting process simulation reveals that larger lead angle enables work material deformation more severely, the maximum temperature on the chip-tool interface reaches 1289°, close to the measured average temperature of 1100°; the predicted average tangential force is 150N, with 7% difference from the experimental data. When the cutting tool nose radius increases to 0.8mm, the chip’s temperature and strain becomes relatively higher, and average tangential force increases 10N. This paper also discusses the disagreement between the predicted and experimental cutting force.
Simulation of Facing Processes of Profiles With Hexagon Cross Section
Authors: Britz Rainer , Ulbrich Heinz
Published: April 2011

The productivity of machine tools is currently limited by the interactions between machine and structure. In this paper models are introduced to describe the components of a turning lathe and the turning process. Therefore a short overview of the theory of multi-body systems with bi- and unilateral contacts is given. This theory is used to embed a detailed model of the cutting process. Therewith, the implementation respects the dynamic effects during the cut. For that, the cutting point of the chisel is extended, with a description of the cutting face. Closing up a facing process is simulated and compared to measurements.
Thermal Modeling of Workpiece Temperature in MQL Deep-Hole Drilling
Authors: Tai Bruce L. , Stephenson David A. , Shih Albert J.
Published: April 2011

This study investigates the workpiece temperature in minimum quantity lubrication (MQL) deep-hole drilling. An FEA-based inverse heat transfer model is developed to estimate the heat generation based on temperature inputs from embedded thermocouples. The temperature distribution in the workpiece is then calculated by the inverse solutions. The method is validated experimentally using a 10 mm carbide drill drilling cylindrical iron workpiece under both dry and MQL conditions. The calculated temperature distribution shows good agreement with experimental temperature measurements. This study demonstrates that the heat generated on the hole wall surface is as significant in workpiece temperature as that on the hole bottom surface in deep-hole drilling.
A Process Comparison of Simple Stretch Forming Using Both Conventional and Electrically-Assisted Forming Techniques
Authors: Jones Joshua J. , Mears Laine
Published: April 2011

A common manufacturing process typically used to create large surface contours in sheet metal is stretch forming. With this process, the ability to create geometrically accurate parts and smooth surfaces is achievable, yet there are certain limits when considering the achievable elongation of the material and the inability to produce sharp contours in the sheet metal. Present research using Electrically-Assisted Manufacturing (EAM) has shown that applying direct electrical current to the workpiece during the forming process can increase the formability and reduce springback of the material, while also lowering the required forming forces. Seeing the advantageous qualities of EAM, this study examines the use of EAM for a simple stretch forming process. Specifically, this research examines this stretch forming process with regards to how the location where the electrical current is applied to the material affects the process, the achievable forming depth without fracture, and the application direction of the current. Overall results displayed that the directional flow of electrical current and the application location did not affect the obtained forming forces or forming depths using EAM.