bluuebunny/crossref_metadata_2025 huggingface dataset:
A Note Concerning the Inadmissibility of Applying the Minimum Work Principle to Metal Cutting
Authors: Rubenstein C.
Published: July 2009

In his formulation of a mathematical model of the orthogonal cutting process, Merchant [1] assumed that the workpiece material is sheared as it approaches a plane extending ahead of the tool from the cutting edge to the free surface of the workpiece. In addition, he proposed the hypothesis that this plane would assume such an inclination as would ensure that the work performed in the cutting process would be a minimum. Deductions from this hypothesis were found to be at variance with experimental observation and on this basis its validity has been questioned but it has never been disproved up to now. In the present work it is shown that the minimum work hypothesis leads to a condition which cannot be fulfilled physically. Further, it is shown that the less demanding hypothesis that the shear plane inclination is such as to ensure that the least work is dissipated in metal cutting is likewise at variance with empirical observation. Accordingly, it is concluded that the minimum work hypothesis is inapplicable to metal cutting.
Roll Dynamics Unit (RDU) Truck Hunting Demonstration
Authors: Punwani S. K. , Arslan A. V.
Published: July 2009

The paper describes a test program conducted in order to demonstrate the capabilities of a Roll Dynamics Unit built at the Transportation Test Center, Pueblo, Colorado. A detailed description of the test program, the RDU and Test Track results, and correlation with a 25 deg-of-freedom analytical truck hunting model is provided. The stability characteristics of conventional 89-ft (27.1-m) lateral flat car, which was borrowed from TOFC service and was equipped with convention three-piece freight car trucks, were defined. During the test the car was equipped with two different sets of wheel profiles, one of which was service-worn. It clearly demonstrated the usefulness of the Roll Dynamics Unit for lateral dynamics testing.
Vibration Modes of a 70-Ton Boxcar
Authors: Orth C. L. , Kachadourian G.
Published: July 2009

Vibration tests were performed on a 70-t boxcar both empty and fully loaded, with two packaging configurations. Nine vibration modes were identified: first roll, second roll, yaw, bounce, pitch, body torsion, body bending, and two lading modes. The effect of friction snubbing, gross weight, and amplitude of motion input at the rails was determined. Test results presented are a summary of modal frequencies, the deflections associated with each mode and the range of frequency variation.
A New Method for Testing the Flow of Frozen Coal
Authors: Nikanjam M.
Published: July 2009

A new test has been developed and successfully employed to evaluate the performance of coal freeze-conditioning agents. The new procedure involves the design of a new shear cell which can be used with the standard flow factor tester used for powders. Coal samples at two moisture levels, 10 percent and 6.5 percent, at a subfreezing temperature, −14°C, with four conditioning agents, were evaluated. Results indicated that Union Carbide’s WINTER-FLO 103 Coal Aid was the most effective freeze-conditioning agent available. An inexpensive portable tester has been developed based on this new method. Such a tester will be capable of predicting the degree of coal flowability in the field.
A Data-Dependent Systems Approach to Optimal Microcomputer Control Illustrated by EDM
Authors: Pandit S. M. , Wittig W. H.
Published: July 2009

A new approach to microcomputer control of manufacturing processes is proposed and illustrated by application to optimal control of electro-discharge machining (EDM). Based on a recently developed methodology called Data Dependent Systems (DDS), it is capable of providing off-line modeling and analysis under working conditions to suggest the best possible strategy for the existing design, an on-line optimal control algorithm, adaptable fine-tuning of the controller to enhance its effectiveness, and finally, design improvements aimed at further increase in productivity and quality. All these features are illustrated by means of DDS models for pulse current and voltage in EDM, one of the least understood and most difficult to control manufacturing processes.
Tool Fracture Probability of Cutting Tools Under Different Exiting Conditions
Authors: Lee Y. M. , Sampath W. S. , Shaw M. C.
Published: July 2009

A large number (150) tungsten carbide (6 weight percent) cutting edges were used to make single cuts in AISI 4340 steel (HB = 235 kg/mm2) at a cutting speed of 200 fpm (61 m/min) and a variety of feeds and entrance and exit angles of workpiece taper. A map is presented showing types of brittle tool fracture occurring at exit for a wide range of feeds and exit angles. Fractures were of two types: 1) those due to very sudden unloading of the tool at exit, and 2) those due to metal adhering strongly to the tool face following a cut. Reasons for the two types of exit failure are briefly discussed.
Real-Time Estimation of Cutting Process Parameters in Turning
Authors: Masory O.
Published: July 2009

A simple method for real-time estimation of the parameters which characterize the relation between cutting force and feed in turning is described. The method produces very accurate results which make it suitable for use in Adaptive Control Constrain (ACC) and Adaptive Control Optimization (ACO) systems. In both cases, models describing different cutting process variables are assumed in which constants are predetermined by off-line experiments. The described method will make it possible to determine these constants on-line.
Some Problems Connected With Balancing of Grinding Wheels
Authors: Gawlak G.
Published: July 2009

In most publications, the unanimous opinion prevails that an increase of grinding machine vibration as well as deterioration of workpiece quality are observed when the grinding wheel imbalance is on the increase. However, various data on the qualitative influence of wheel imbalance on the realization of the grinding process occur. In this paper a theoretical explanation of the influence of wheel imbalance on the dynamics of grinding, as well as the course and results of investigations proving theoretical considerations, are described. The widely known opinion is that only one-plane balancing of the grinding wheel is sufficient. Also the majority of wheel balancing equipment has the capability of only one-plane imbalance corrections. The purpose of the present paper is to prove that the wheels used in precision grinding always should be balanced in two planes.
Structures Requirements for a Manned Space Station
Authors: Mar J. W.
Published: July 2009

The structural designer, when asked to design the manned space station (MSS), will go over a checklist which includes: design criteria, factors of safety, environment, optimum design, methods of analyses, materials, and configurations. The structural designer of the manned space system must imbibe quantitative numbers which are several orders of magnitude different than those which are commonplace for earthbound structures. Additionally, the designer must bear in mind the methods of assembly and, in fact, should help in the design of the methods of assembly. Of special importance to the success of the station are the capabilities of the space construction engineers (SCE) who are the personnel who will perform the final assembly in the environment of zero g. The structural designer has a vested interest in defining and characterizing the role of the SCE because the details of the structure will to an important degree be determined by the methods of assembly.
Statistical Analysis of Thermal Shock Data
Authors: Merten C. W. , Steinhurst W. R.
Published: July 2009

Hazard plotting and maximum likelihood estimation (MLE) are used to determine Weibull parameters for single cycle thermal shock tests performed on WC-Co specimens. Data for each sample fall into three classes: tests below a threshold prequench temperature for which failure never occurs; tests above some higher prequench temperature for which failure is universal; and tests at intermediate prequench temperatures for which both failures and nonfailures are interspersed. Hazard plots in the region of the third class show a good Weibull fit. For some samples, the shape of the hazard plots indicates competing risks. MLE of the Weibull parameters for each sample is performed and the estimates are compared. Failure models which might account for the shape of the hazard plots are proposed.
Computer-Assisted Engineering Data Base
Authors: Dube R. P. , Johnson H. R.
Published: July 2009

General capabilities of data base management technology are described. Information requirements posed by the space station life cycle are discussed, and it is asserted that data base management technology supporting engineering/manufacturing in a heterogeneous hardware/data base management system environment should be applied to meeting these requirements. Today’s commercial systems do not satisfy all of these requirements. The features of an R&D data base management system being developed to investigate data base management in the engineering/manufacturing environment are discussed. Features of this system represent only a partial solution to space station requirements. Areas where this system should be extended to meet full space station information management requirements are discussed.
Experimental Verification of a Catastrophe Theory Model of Metal Cutting Chip Formation
Authors: Klamecki B. E.
Published: July 2009

The problem of predicting changes in the chip formation process in metal cutting was considered. An analytical model which predicts the shear angle as the cutting tool approaches the end of the workpiece was developed. The model was of the orthogonal cutting geometry with shear along a plane and the shear angle predicted from a minimum shear energy postulate. The model predicted two shear angles near the end of cutting and these were compared with measured shear angles for cutting different work materials with varying rake angle tools.
Evaluation of Selective Coolant Application for the Control of Work Roll Thermal Expansion
Authors: Bennon W. D.
Published: July 2009

A fully implicit three-dimensional, control-volume-based, finite difference model has been developed for predicting temperature distributions and thermal expansion in a rotating variable section cylindrical domain. Included in the model formulation is a technique for accommodating boundary conditions that are geometrically nonorthogonal with respect to the surface finite difference grid. Steady-state results applicable to hot and cold rolling processes are presented, with emphasis placed on the evaluation of selective coolant application as a means for controlling the axial distribution of radial roll thermal expansion.
Algorithms to Deconvolve Stylus Geometry From Surface Profile Measurements
Authors: DeVries W. R. , Li Cheng-Jih
Published: July 2009

Stylus methods for measuring surface topography impose certain limits on resolving the true profile of a surface. These limits are primarily due to the finite geometric size of the stylus. In this paper, kinematic and geometric algorithms are developed to compensate for stylus geometry so as to present a better picture of the true surface profile. To demonstrate their effectiveness, these algorithms are applied to simulated deterministic and stochastic profile measurements.
Slip-Line Field and Stress Distribution for Flat Rolling in Model Test
Authors: Nishitani T. , Hasegawa A.
Published: July 2009

In the flat rolling, there are many theoretical investigations for finding the slip-line field and the stress distribution under the condition of rigid-perfectly plastic strip or ideal work-hardening strip. However, the propriety of hypothesis used has been ascertained only partly. Though some experimental investigations have been performed to find the roll pressure and so on, the relations between their results and the corresponding actual stress states are not analyzed sufficiently. In the present paper, the proposed photoviscoplasticity is applied to analyze the slip-line field, stress states near the contact surface and the normal roll pressure of the strip in the model test of the flat rolling. As the results, the experimental slip-line field was remarkably different from the theoretical one. The normal roll pressure was appreciably affected by the deformation speed.
An Integrated Machining Process Design Simulator for the Optimal Design of Face Milling Systems
Authors: Lee S. J. , Kapoor S. G. , DeVor R. E.
Published: July 2009

An Integrated Machining Process Design Simulator (IMPDS) is developed and applied as a general tool for the design of face milling systems. The simulator includes four modules to accommodate the important factors that affect face milling operations. These modules are: a general purpose finite element program to analyze structural characteristics, a mechanistic face milling force module for both open-loop and closed-loop cutting force simulations, a machinability module to evaluate cutting process performance, and an efficient optimization module to automate the design process. The design variables, constraints, and objective function of the entire system include structural element size, shape, and weight, cutting forces and vibrations, and other machinability measures including tool life, metal removal rate, and surface finish. Several examples are included to demonstrate the capability of IMPDS in the machining system design process.
On a Methodology for Establishing the Machine Tool System Requirements for High-Speed/High-Throughput Machining
Authors: Komanduri R. , McGee J. , Thompson R. A. , Covy J. P. , Truncale F. J. , Tipnis V. A. , Stach R. M. , King R. I.
Published: July 2009

This paper presents a methodology for determining the machine tool system requirements for high-speed machining (HSM)/high-throughput machining (HTM). Both technological and economic factors should be considered in the formulation of the model for determining machine tool system requirements. The HSM function model is given here in the form of ICAM-defined (IDEFo) charts with corresponding text. For machining most aluminum alloys, the maximum cutting speed is not limited by tool life, and the technology for high-speed machine tools (spindles, table drives, controls, chip management, and other features) exists today. Therefore, HSM of aluminum alloys can be implemented. Selection of a suitable HSM system involves detailed technological analysis and economic justification for a given part-family production configuration. The recent introduction of Si3N4 based tool materials has enabled significantly higher cutting speeds (up to 1524 mpm or 5000 sfpm) in the machining of gray cast iron. However, the machine tools using this type of tool material should be more rigid and capable of higher power, higher speed, and faster feed in order to increase productivity and reduce manufacturing costs. In the machining of the difficult-to-machine materials (e.g., superalloys), the cutting speed is still limited by tool wear. Nevertheless, a high-throughput machining (HTM) strategy is pertinent for this application.
Optimization of Abrasive Life in Ultrasonic Machining
Authors: Dharmadhikari S. W. , Sharma C. S.
Published: July 2009

Based on two models of material removal in ultrasonic machining, developed in an earlier work, conditions for optimum abrasive life for the objective functions of minimum cost per unit volume of material removed, maximum production rate and maximum profit rate are presented. A simple nomogram is designed for the determination of optimum abrasive life. Sensitivity studies of production rate and profit rate functions are presented. An illustrative example highlights the application of the analysis.
On-Line Tool Wear Sensing for Turning Operations
Authors: El Gomayel J. I. , Bregger K. D.
Published: July 2009

A sensing device was developed to measure tool wear indirectly by monitoring the change of the workpiece diameter during turning operations. The change in the diameter was sensed by electromagnetic sensors which gave a voltage output directly related to the gap between the sensor and the workpiece. After trying different alternatives, the final arrangement was set up with two sensors operating in a differential mode which allowed compensation for deflections and vibrations. The electromagnetic sensors could detect minute wear for the different cutting conditions used (speeds of 350–550 ft/min, feeds from from 0.0208–0.0232 in./rev. and depths of cuts from 0.030–0.100 in.). The experimental data obtained for flank and nose wear were in agreement with the results obtained from the conventional method of measuring the wear by a toolmaker’s microscope.
A Comparison of Tension Leveling Theories
Authors: Stark G. K.
Published: July 2009

In this note three of the better known theories for the calculation of elongation in the tension leveling process are compared, apparently for the first time. By plotting the results of each theory in a simplified form not previously seen, it is shown that the accuracy of the most complex theory is matched by a much simpler theory, thus eliminating the need for a numerical solution. This approach allows tension/elongation results to be read with confidence from a single linear plot for a wide range of materials and leveling conditions.
An Experimental Investigation of the Effects of Various Reagents on Orthogonal Cutting of Metals
Authors: Seah K. H. W. , Tay A. O.
Published: July 2009

In orthogonal machining experiments on copper and aluminum in which chemical reagents were applied to the work surfaces and allowed to dry completely before cutting, it was found that tool forces and chip morphology were greatly altered depending on the nature of the reagent and work material. The results are discussed with special emphasis on the difference in results observed in copper and aluminum.
Improving Stability of Slender End Mills Against Chatter
Authors: Ismail F. , Bastami A.
Published: July 2009

The strongest mechanisms that contribute to machining chatter are regeneration and mode coupling. Special designs of milling cutters have evolved with the aim to increase stability against chatter by disturbing the regeneration mechanism. However, in the case of slender end mills, the mode coupling remains most active. In this work, a new approach is presented where a design change of the cutter is suggested to weaken the mode coupling mechanism. Time domain simulation of the development of chatter showed that using this approach significant increase in stability could be achieved. Cutting tests of aluminum with the modified end mills confirmed simulation results.
An Integrated Quality Systems Approach to Quality and Productivity Improvement in Continuous Manufacturing Processes
Authors: Dooley K. J. , Kapoor S. G. , Dessouky M. I. , DeVor R. E.
Published: July 2009

An integrated quality systems methodology is presented as a framework within which the concepts of process control can be used to improve quality and productivity. The process is mathematically described by stochastic time series models which statistically describe how inputs and outputs interact. Several different methods for fault identification, including autocorrelation checks of the model residuals, forecasting prediction intervals, and the cusum chart are compared in terms of relative performance. A helix cable manufacturing process is simulated and analyzed by the methodology and faults are identified and suggestions are made for process improvement. Through the simulation these time series control chart methods are shown to be much more effective than conventional methods such as Shewhart control charts.
Demonstration of a New, Fast Probability Integration Method for Reliability Analysis
Authors: Wu Yih-Tsuen
Published: July 2009

The performance of a new, fast probability integration method which combines an improved equivalent normal concept and a scheme for linearizing a quadratic limit state is carefully examined. The examples tested include various combinations of linear and nonlinear limit states with normal and non-normal variables; some examples are considered the worst possible cases. It is demonstrated that the new method is able to provide accurate probability-of-failure estimates for most cases and performs reasonably well when the Rackwitz-Fiessler method produces severe errors.
Determination of the Interface Heat Transfer Coefficient for Non-Isothermal Bulk-Forming Processes
Authors: Semiatin S. L. , Collings E. W. , Wood V. E. , Altan T.
Published: July 2009

Experimental and analytical techniques have been developed for the determination of the interface heat transfer coefficient for nonisothermal bulk-forming processes. A fixture consisting of two flat IN-100 alloy dies was instrumented with high-response thermocouples. With this tooling, heat-transfer experiments were conducted in which (1) the two dies were heated to different temperatures and brought together under varying pressure levels and (2) the two dies were heated to the same temperature and were used to upset an aluminum alloy 2024-0 ring specimen heated to a higher temperature. Data from both sets of tests were analyzed to determine heat-transfer coefficients by using calibration curves derived from analytical and finite-difference method solutions. By this means, the effects of interface pressure, deformation, and deformation rate on the heat-transfer coefficient were established.
The Influence of Lateral Wall Vibrations on the Ultrasonic Welding of Thin-Walled Parts
Authors: Jagota A. , Dawson P. R.
Published: July 2009

The welding of thin-walled thermoplastic parts by ultrasonic vibrations is often seriously impaired by variability in bond strength along the interface of the welded parts. This study shows that the strength of the weld is related to the vibrations in a direction normal to the walls of the parts. Specifically, for the typical thin-walled part studied, the strength has been found to have an inverse dependence on the amplitudes of the relative lateral motion at the interface. Free vibration experiments and finite element calculations for natural frequencies have also been conducted that provide supporting evidence of the vibration modes observed.
Analysis of the GMAW Process for Microprocessor Control of Arc Length
Authors: Kannatey-Asibu E.
Published: July 2009

Control of arc length is an essential component of the automation of arc welding processes. It is even more critical in gas metal arc welding where the arc length can vary substantially since it is closely tied to the melting process. Variations in arc length can greatly affect the quality of the weld produced. Even though there are currently systems available for controlling arc length, the theory necessary for microprocessor control is not fully developed. This paper develops a model of the gas metal arc welding process as a basis for arc length control, using the input to the wire feed drive motor as the control signal. The weld process is found to be first order after linearization, and that, coupled with the drive motor dynamics, produces a second-order system. The model is verified experimentally and is found to correlate very well with experimental results, the calculated time constant for the welding system in the constant current mode being 1.7 s, while the measured value is approximately 1.5 s.
Acoustic Emission from the Face Milling Process—the Effects of Process Variables
Authors: Diei E. N. , Dornfeld D. A.
Published: July 2009

This study investigates the nature of the acoustic emission (AE) signal generated during single and multitooth face milling of steel. For this purpose, cutting tests were conducted on a vertical milling machine to determine the effects of cutting parameters, especially the angle of tool engagement and disengagement, the varying chip thickness, and the number of engaged teeth. The results show good correlation between the rms AE signal and the severity of the contact conditions during chip formation and at tool entry and exit. Cutting forces were also measured and a qualitative correlation between the specific AE rms voltage and the specific cutting force is seen.
Air Flow in Yarn Texturing Nozzles
Authors: Acar M. , Turton R. K. , Wray G. R.
Published: July 2009

The air-jet texturing process, a purely mechanical means of texturing continuous filament yarns, is described. Industrial texturing nozzles are reviewed and categorized in two groups, either as converging-diverging or cylindrical type nozzles. A mathematical model is developed for the complex airflow in cylindrical type texturing nozzles, and experimental data obtained from various nozzles verify the flow predicted by this model. The mathematical model is also shown to be in good agreement with the data obtained from a modified experimental nozzle, which has a trumpet shaped diverging exit. Further experimental work with a scaled-up model of a typical industrial texturing nozzle is also reported.
Effects of Accelerated Tests on Shear Flow Stress in Machining
Authors: Jain V. K. , Gupta B. K.
Published: July 2009

Facing and taper turning tests (also known as accelerated cutting tests) are commonly used for the evaluation of machinability of materials. Of late, it has been reported that instantaneous values of tool-chip interface temperature, tool wear, shear angle, etc, in longitudinal turning are different from the corresponding values in accelerated cutting. This effect has been attributed to shear strain acceleration phenomenon. Materials behavior during accelerated cutting changes in a manner different than that in longitudinal turning. To test this hypothesis, experiments have been conducted using HSS as tool material and mild steel as work material. It has been concluded that shear flow stress during accelerated cutting is governed by shear strain acceleration and its governing parameters. Shear flow stress value is highest during facing, lowest in taper turning and in between the two during longitudinal turning.
A Model of Tool Fracture Generated Acoustic Emission During Machining
Authors: Diei E. N. , Dornfeld D. A.
Published: July 2009

This paper presents details of a study of the fundamental nature of the high amplitude acoustic emission (AE) signal generated during the complete breakage of cutting tools. A quantitative model of the peak AE rms voltage, incorporating the effects of tool material and the area of the fracture surface, is proposed. The model, derived from results of Linear Elastic Fracture Mechanics, and stress wave propagation in solids, is shown to be in good agreement with results of notched carbide insert fracture during turning and face milling operations.
Analysis of Alignment Errors in a Laser-Based In-Process Cylindricity Measurement System
Authors: Kim K. , Eman K. F. , Wu S. M.
Published: July 2009

A new laser-based in-process measurement system has been developed to measure the cylindricity errors in boring operations. This paper presents a mathematical model of the alignment errors and examines the effects of each alignment error on the overall system’s accuracy. A compensation scheme for the alignment errors is suggested to assure the accuracy of the measurement.
A New Time Domain Multiple Input Modal Analysis Method
Authors: Cho D. W. , Eman K. F. , Wu S. M.
Published: July 2009

A time domain approach for multiple input modal analysis of oscillatory systems is proposed. The mathematical foundation for the approach is given along with its applications to a simulated lumped parameter system and the structural dynamics analysis of a milling machine. It has been shown that the proposed multivariate time series models are able to identify the complex mode shapes from multiple input structural test data. The advantages of the proposed method in comparison to existing methods are also highlighted.
Computer Models for the Mechanics of Three-Dimensional Cutting Processes—Part I: Theory and Numerical Method
Authors: Stephenson D. A. , Wu S. M.
Published: July 2009

A numerical modeling method for predicting chip form and power requirements in three-dimensional cutting processes is described. The method is based on variational (energy) results from the theory of rigid-plastic materials and is applicable to the steady-state cutting of ductile metals. The analysis involves mainly material behavior assumptions and for simple material models yield results similar to the widely-used minimum work approach. In Part I the theoretical basis of the method and the appropriate numerical algorithm (gradient search or steepest descent) for implementation in specific processes are described. Results for the oblique end turning and drilling processes are compared with experimental data in Part II.
Driving Mechanism for Vibrating Bristled Vehicle for Small Pipe
Authors: Morimitsu T. , Sakata H. , Tsujimura T.
Published: July 2009

A novel vibrating bristled vehicle for small pipes is proposed. Its drive mechanism with rotating eccentric weight is simulated and analyzed. The investigation shows that the vibrating bristled vehicle can move smoothly through the pipe. The motion experiments and simulations are conducted using a vehicle with 16 bristles in order to clarify the relationship between the vehicle velocity and the angular velocity of the rotating eccentric weight. The calculated vehicle velocity agrees with the experiments.
Comprehensive Dynamic Cutting Force Model and Its Application to Wave-Removing Processes
Authors: Wu D. W.
Published: July 2009

A new concept is taken to develop a comprehensive cutting force model for analyzing the dynamic behavior of the machining process. The model is derived based on the principles of the cutting mechanics, and takes into account the fluctuation of the mean factional coefficient on the tool-chip interface as well as the variations of the normal hydrostatic pressure distribution and the shear flow stress along the primary plastic deformation zone. The model has been tested through computer simulation for orthogonal wave-removing processes by reference to an existing experimental evidence. The result indicates a generally good agreement with the theoretical predictions except that the amplitude of the force variation in the feeding direction appears to be underestimated. An explanation is also given.
An Approximate Three-Dimensional Metal Flow Analysis for Shape Rolling
Authors: Kennedy Kevin F.
Published: July 2009

An approximate three-dimensional metal flow analysis for shape rolling is developed. The analysis, which is presently applicable to rod rolling, is based on an upper-bound approach in which an iterative numerical procedure is used to minimize the energy dissipation rate to obtain kinematically admissible velocity field solutions of the rolling problem. Once the velocity field and the final shape of the plastically deforming body are known, then elementary stress analysis techniques are used to determine the force related aspects of the rolling problem. It is assumed that the rolled material is rigid perfectly plastic, and only the purely mechanical aspects of the metal deformation problem in rolling are considered assuming isothermal conditions. The analysis shows good agreement with elongation and roll separating force measurements in the hot rolling of mild carbon steel for a variety of workpiece and roll cross-section geometries commonly used in rod rolling.
A Simplified Identification Method for Autoregressive Models of Cutting Force Dynamics
Authors: Olgac N. , Guttermuth J. R.
Published: July 2009

The quality and the duration of the metal removal process are two fundamental topics of today’s manufacturing technology. This paper presents a technique addressing the quality issue. There are numerous parameters involved in the dynamics of the cutting process. Some of them are treated as the major control parameters in this study, such as the depth of cut, feed rate, and the axial tool position. The tool-tip/workpiece interactions are elaborated, with the hope that a close correlation exists betwen the quality of the workpiece surface and the tool forces. The variations of the control parameters are examined in order to evaluate their influences on the tool forces. A numerical representation of the tool force dynamics is introduced using the time series analysis. This numerical technique is expanded to generate some relationships between the identifiers of the time series and the above stated control parameters. These relationships require a prohibitively large number of individual tests. The main contribution of the present study is to reduce the required number of tests by using this expanded numerical technique. Additionally, this technique leads itself to be utilized as an on-line identification scheme. This identification process is expected to comprise a portion of the future control strategies of metal machining. The experimental force registrations and the corresponding values obtained from the numerical representation are compared in an error analysis. Close agreement of the two groups of values is observed and tabulated within the text.
On the Plane Stress to Plane Strain Transition Across the Shear Zone in Metal Cutting
Authors: Klamecki B. E. , Kim S.
Published: July 2009

The effects of the stress state transition from plane stress at the workpiece surface to plane strain in the central region of the chip formation zone were studied. A finite element analysis of the incipient chip formation process was performed. The model included heat generation and temperature induced workpiece material property changes. The primary result is that the unique high strain, high strain rate, large free surface characteristics of the metal cutting process can result in qualitatively different deformation behavior across the shear zone. Temperatures are higher in the regions near the surface of the workpiece than in the central region. In extreme cases, this will result in strain hardening behavior in the plain strain regions and thermal softening of the work material near the surface.
Construction Techniques for Factory Floor Expert Systems
Authors: Kershner J. D. , Lorenz R. D.
Published: July 2009

This paper addresses the specific problems encountered when building an expert system for use in a manufacturing process. These problems include: general unfamiliarity of the experts with expert systems, the diffused nature of the expertise, the low availability of the experts, and the users fear of being replaced or constrained by the computer system. The paper addresses these problems by presenting specific strategies developed in the construction of an expert system for use in controlling a plating process for electronic components.
A Decision Making Approach to Machining Control
Authors: Chryssolouris G. , Guillot M. , Domroese M.
Published: July 2009

This paper describes the attempt to combine A. I. techniques with process knowledge in order to devise a flexible control strategy for machining. This is done by treating the control of the machining process as a decision making problem, thereby establishing a decision making framework to be applied in tandem with multiple sensors.
Experimental Analysis of Ironing of Thin Metal Cups
Authors: Saito Masami , Saiki Hiroyuki , Kawai Nozomu
Published: July 2009

A new testing apparatus has been made to analyze the ironing of thin metal cups. The frictional force Fp that acts axially along the punch side could be measured independently of the punch head load Pb, besides the ironing punch load P(=Fp + Pb). The frictional force Fp has two main constituents, one acting on the punch side in the deformation zone and the other on the punch side in contact with the thinned cup wall after ironing. These were separately estimated by using the measured stripping load of the ironed cup. This makes it possible to estimate accurately the axial stress acting on the ironed wall at the die exit, and to calculate the frictional coefficients at the die surface and the punch side. Thus cup fracture and friction during ironing could be analyzed quantitatively. The galling at the die-metal interface is unexpectedly enhanced with higher friction on the punch side. Cup fracture during ironing is probably affected by the galling.
Galling and Friction in Ironing of Thin Aluminum Cups
Authors: Saito Masami , Saiki Hiroyuki , Kawai Nozomu
Published: July 2009

An experiment of ironing of aluminum cups has been carried out under various lubrication conditions. The surface appearances of the ironed cups can be classified into five main groups according to the extent of the damage caused by galling. The extent has a good positive correlation with the frictional coefficient (μd) at the die surface for every lubricant used on the punch side. The cup surface gradually deteriorates as the punch side friction (μp) increases, due to the increase in normal pressure over the die-metal interface, and vice versa. Thus it is possible to evaluate the surface appearances by means of the two frictional coefficients μd and μp. The frictional condition for a burnished smooth surface has been obtained for pure aluminum cups ironed by a tool-steel die.
Motion Control of Manipulators with Closed-Form Inverse Solutions Near Wrist Singularities
Authors: Lai Jim Z. , Menq C. H.
Published: July 2009

Two algorithms, the degenerate axis and iterative methods, are developed for the motion control of manipulators with closed-form solutions in the neighborhood of singularities. These two methods theoretically guarantee a robot’s position accuracy. The degenerate axis method may not work well when a robot’s orientation and location increments become finite. If a robot is moving with slow speed or the interpolation time is in the order of microsecond, the location and orientation increments are small. In this case, the degenerate axis method is favored for it has less computation than that of the iterative method. Two examples are given to illustrate the concepts presented in this paper. Although it cannot be proved that the iterative scheme gives the required position accuracy and minimizes the orientation error, the results seem to show that this scheme converges to an acceptable solution. It is believed that the iterative method is the first of its kind to solve the singular motion control problem by using a robot’s closed-form inverse kinematics. Simple computation for the iterative scheme makes it possible to be implemented in many industrial robots.
Finite Element Analysis of an Involute Gear Drive Considering Friction Effects
Authors: Chen Wen-Hwa , Tsai Pwu
Published: July 2009

A rigorous and accurate finite element model has been developed and applied to deal with an involute gear drive considering friction effects. The loss of torque transmission due to friction and effective friction coefficient are evaluated and computed. The rolling and/or sliding behaviors between two engaged gears during an engagement cycle are also discussed. The patterns of stress distributions and deformations of two contact gears at various engagement angles are then presented. Excellent correlations between the calculated results and referenced experimental data can be found.
A Fast Algorithm for On-Line Machining Process Modeling and Adaptive Control
Authors: Fassois S. D. , Eman K. F. , Wu S. M.
Published: July 2009

A fast, on-line algorithm for machining process modeling and control is proposed. The modeling is accomplished via a new recursive estimator that offers good accuracy at a minimal computational load. Its Fast Kalman-type version, that further reduces its computational complexity, is also presented. The adaptive controller, which is based on on-line identification and closed-loop pole assignment, is characterized by a low computational load and no need for a priori process information. The analytical results are supplemented by numerical simulations, where the proposed scheme is used for the control of a turning operation and shown to offer very good performance under noisy conditions and suddenly changing machining dynamics.
Effects of Superheat and Volume Fraction in the Mixalloying Process
Authors: Oktay S. Tu¨rker , Chu Chong N. , Saka Nannaji , Suh Nam P.
Published: July 2009

Dispersed-phase microstructures of Pb-Zn, Pb-Zn-Sn, and Pb-Al immiscible alloys were produced by the Mixalloying process. The superheat and the volume fraction of the impinging metal jets were systematically varied and their effects on the resulting microstructures were examined. High superheats resulted in coarse microstructures. At lower volume fractions of the second-phase, particles of the minor phase were well dispersed. As the volume fraction approached 0.5, however, the structure became interconnected. The minor phase size, defined either as the mean particle diameter or the mean linear intercept, followed the log-normal distribution, and was the smallest in the Pb-Zn-Sn system for the entire volume fraction range.
On the Effects of Turning Process Asymmetry on Process Dynamics
Authors: Klamecki B. E.
Published: July 2009

The implications of a fundamental asymmetry in the lathe turning process are considered. The asymmetry is the directional dependence of system stiffness that exists at the cutting tool edge. Depending on tool edge displacement, the system stiffness is determined by the workpiece stiffness or the relatively much stiffer tool support structure. A one degree-of-freedom, lumped parameter model with nonlinear stiffness is constructed and subjected to a periodic forcing. Time and frequency domain analyses show that extremely complex dynamic behavior can occur in this simple system.
Safety Throats for Meat Grinding Equipment
Authors: Barnett R. L. , Litwin G. , Hutter G. M.
Published: July 2009

Every engineered system represents a tradeoff among at least three criteria: cost, safety, and function. For a meat grinder with a safety feed throat and stomper, common sense tells us that operator safety will increase as the throat diameter gets smaller and its length gets longer. It is just as apparent that the feed throat capacity will decrease accordingly. This paper quantifies the relationship among the throat parameters, the capacity, and the stomper force.
Identification of Joint Parameters for a Taper Joint
Authors: Kim T. R. , Wu S. M. , Eman K. F.
Published: July 2009

A new methodology of combining the finite element model of a structure with the results of the experimental modal analysis technique was applied to a tool-holder system with a taper joint to identify its joint stiffness and damping characteristics. The underlying background is briefly introduced followed by an experimental verification of the proposed method.
On-Line Identification of End Milling Process Parameters
Authors: Fussell B. K. , Srinivasan K.
Published: July 2009

A method for on-line identification of process parameters relating the feedrate to the machining force in end milling operations is described here. Such on-line identification of changing process parameters is necessary for parameter adaptive force feedback control systems which use feedrate manipulation to maintain a specified cutting force in the presence of varying machining conditions. A simple model form for the complex process mechanics is preferred for the adaptive control application and is proposed here. Accurate low order models for the end milling process are obtained by using the measured feed drive velocity and the machining force as the input and output signals, respectively, and by choosing a sampling interval equal to the tooth delay period. An identification scheme based on the recursive minimization of the sum of the squares of the modeling error is used here, with special emphasis on techniques to keep the estimation scheme alert while avoiding oscillatory parameter estimates. The effectiveness of the proposed process model and estimation scheme under open loop conditions is confirmed by simulation and experimental tests involving changes in the axial and radial depths of cut and in the feedrate. The parameter estimates generated are accurate and responsive to the changing cutting conditions and are steady and accurate under constant cutting conditions because of the simplicity of the proposed model. The estimation scheme described here accommodates the effects of cutter runout, tilt, and interrupted cutting by the multiple flutes more readily and with less detriment to parameter estimates than other schemes reported in the literature. The effectiveness of the estimation scheme under closed loop conditions is also verified by simulation.
Blank Development and Tooling Design for Drawn Parts Using a Modified Slip Line Field Based Approach
Authors: Karima M.
Published: July 2009

Box shaped parts demonstrate unusual characteristics as opposed to the drawn cylindrical cups. A novel approach for blank development, based on the modified plane strain slip line field (SLF), is presented in this work. The approach is to balance the element volume between the final position in the wall and the starting position in the flat flange. The end result of this SLF based unfolding technique is a set of elements representing the deformation path of the part. By post-processing the information on the nodal coordinates and invoking the variational principle in its incremental form, the strain distribution in the flange and the wall stresses are determined. A methodology is also presented for understanding the implications of the metal flow lines for tooling design.
The Effect of Tool Joint Stiffness on Drill Pipe Fatigue in Riser Ball Joints
Authors: Ertas A. , Blackstone W. R. , Majumdar B. K.
Published: July 2009

It is well known that the ball joint in a marine riser can cause fatigue damage in the drill pipe passing through. Previous investigators have assessed the damage done for a lower ball joint angle of 3–5 degrees (drilling) and 1–3 degrees (running casing). This paper extends that work to deep water operations in which an upper ball joint is also present. Also, it is shown, via finite element models, that tool joint bending stiffness can have a significant effect on fatigue life. Fatigue damage calculations, including this heretofore unconsidered effect, are presented for various ball joint angles and drill pipe tensions.
Rail Head Geometry, Rail Rolling and Wheel-Rail Contact Tilting Analysis for Heavy Axle Loads
Authors: Kumar S. , Singh S. P.
Published: July 2009

This paper presents analytical considerations which are important to design a rail head for reducing rail damage due to heavy axle loads. There are two important parameters of design of rail crown: (1) the wheel tread rail crown contact stress and (2) the contact tilt angle called the β angle. Contact should not be allowed to move out of the rail crown. Analysis of lateral oscillations of new and worn wheel sets shows that they do not impose an engineering constraint on the choice of rail crown radius. Rail rolling on curves due to lateral creepage forces is however of great importance in rail loading and stresses. The point of contact location is significantly affected by such roll. For the two commonly used rails, 132 RE and 136 RE, this roll results in the contact moving to the part of the rail head with radius of 1 1/4 in. Such movement of the contact also develops rapidly when hollowed worn wheels roll on flattened worn rails. It is pointed out that this condition results in forces higher than the wheel load and stresses more than twice the value developed when the contact is within the rail crown and that this is most likely responsible for many of the rail failure problems including cracking, shelling, and fractures. A design analysis of rail crown including Hertzian contact and rail twist considerations shows that none of the three current rails analyzed satisfy the criteria developed for good rail head design. A suitable ellipitical crown should prove better. Finally a systems approach to rail wheel interaction with a number of design recommendations is given.