bluuebunny/crossref_metadata_2025_split huggingface dataset:
A hybrid neural network-feature-based manufacturability analysis of mould reinforced plastic parts
Authors: Marquez M , White A , Gill R 
Published: October 2002

The purpose of this research is to establish a method to perform manufacturability analysis of reinforced plastic components by using a hybrid system including automatic feature recognition and a feature-based assessment of manufacturability. Feature recognition plays a fundamental role and is usually the first step in downstream activities concerning the product development process, such as design for manufacturing, design for assembly and process planning. Critical features to successful reinforced plastic moulding are identified, and the relationship between geometric information of the model, expert geometric reasoning and knowledge of related manufacturing processes is clarified and predetermined in a useful and efficient manufacturability analysis system. A prototype system using solid modelling, object-oriented programming and a rule-based system, which is intended to consider the fuzziness of the expert reasoning about reinforced plastic component design, is under construction to test the proposed concepts. The major contribution from this work is a consistent and systematic methodology for analysing the geometry of models, allowing assessment of manufacturability. This methodology considers available manufacturing process capabilities, materials and tooling required. Some virtual parts have been used to test the system, showing promising results.
Cutting conditions and tool optimization in the high-speed milling of aluminium alloys
Authors: López de Lacalle L N , Lamikiz A , Sánchez J A , Cabanes I 
Published: October 2002

The high-speed milling (HSM) of aluminium alloys was one of the first fields of application of this technology. It might be thought that this is the field where the technology has been most commonly used, with the largest number of users, and is therefore best known. However, the continuous improvements in modern machine tools on the one hand, together with the development of new tool materials and tool geometries on the other, have produced a constant increase in the cutting conditions (i.e. speed and feed rate). During the past 5 years the use of high-silicon (12–21 per cent) castings has grown considerably owing to the fact that a high silicon content results in excellent properties, mainly wear and high-temperature resistance. However, the machinability of the material becomes too poor on account of its abrasiveness. Aluminium alloys for structural elements in the aeronautical industry are nowadays high-speed milled (HSMed) at very high removal rates, which makes possible the use of monolithic structures instead of sheet metal formed structures. Complete removal of coolant fluids has not been possible so far, but their use can be effectively minimized if techniques such as micropulverization are applied. In this paper, the problems in the machining of the previously mentioned alloys are analysed, along with the possibilities of the so-called minimum quantity of lubricant (MQL) technique.
An application of rough set theory to defect detection of automotive glass
Authors: Lee S , Vachtsevanos G 
Published: October 2002

A technique based on rough set theory is investigated for identifying defects on a backlight (a rear window of a vehicle with a defrost circuit). Since replacement of defective backlights results in a significant financial loss, automobile manufacturers are trying to remove defective backlights during the manufacturing process. Therefore, an automated inspection system based on infrared (IR) imaging techniques has been developed to detect backlight defects such as missing lines or hotspots, where the most challenging task is identifying hotspots from their artefacts. Feature selection techniques based on rough set theory are explored in this short communication and are used to extract a feature vector, which increases inspection accuracy as well as reduces computational complexity. The theory is also applied to generate decision rules, which can be simply added to existing inspection systems to assist the operators in their decision-making process. The proposed inspection system is expected to provide more reliable fault detection with low rate of false alarms than currently available systems.
The effects of cryogenic cooling on chips and cutting forces in turning AISI 1040 and AISI 4320 steels
Authors: Dhar N R , Kishore Nanda S V , Paul S , Chattopadhyay A B 
Published: October 2002

Application of conventional cutting fluids often cannot control the high cutting temperatures, especially in high production machining. In addition, they are a major source of pollution in machining industries. Cryogenic cooling is a potential environmentally friendly clean technology for desirable control of the cutting temperature. The present work deals with experimental investigations on the role of cryogenic cooling by liquid nitrogen jets on chip formation and cutting forces in turning AISI 1040 steel and AISI 4320 steel at industrial speed—feed combinations by two types of carbide inserts of different geometrical configurations. The experimental results indicate the possibility of a substantial reduction in cutting forces by cryogenic cooling, which enabled a reduction in cutting forces by favourable chip formation, chip—tool interaction and also retention of tool sharpness due to reduced cutting temperature. Thus cryogenic cooling, if properly employed, is not only environmentally friendly but can also improve machinability characteristics.
An analytical solution for transient temperature distribution in fillet arc welding including the effect of molten metal
Authors: Jeong S. K. , Cho H. S. 
Published: October 2002

This paper presents an analytical solution to predict the transient temperature distribution in fillet arc welding, including the effect of the molten metal generated from the electrode. The analytical solution is obtained by solving a transient three-dimensional heat conduction equation with convection boundary conditions on the surfaces of an infinite plate with finite thickness, and mapping an infinite plate on to the fillet weld geometry, including the molten metal with energy equation. The electric arc heat input on the fillet weld and on the infinite plate is assumed to have a travelling bivariate Gaussian distribution. To check the validity of the solution, flux cored arc (FCA) welding experiments were performed under various welding conditions. The actual isotherms of the weldment cross-sections at various distances from the arc start point are compared with those of the simulation result. As the result shows a good accuracy, this analytical solution can be used to predict the transient temperature distribution in the fillet weld of finite thickness under a moving bivariate Gaussian distributed heat source. The simplicity and short calculation time of the analytical solution provides the rationale for using the analytical solution to model the welding control systems or to obtain an optimization tool for welding process parameters.
Strategy investigation of precise robotic assembly operations with symmetric regular polyhedral objects
Authors: Qiao H , Tso S K 
Published: October 2002

In this paper, a general strategy for the precise robotic assembly of symmetrical regular polyhedral objects is presented, according to the character of the objects being assembled. The assembly operations with force sensors included are discussed. The general strategy of the operations with force sensors included is first developed. The assembly operations without relying on force sensors are next analysed. This method can be generally used in industry for the precise assembly operations for symmetric regular polyhedral objects. This paper covers the following items: An important problem demanding solution in the general robotic assembly operations with force sensors is presented. The general strategy investigation for the assembly operations with force sensors included is analysed. The mappings, firstly, between the directions of the contact forces and the location of the peg in the hole coordinate frame and, secondly, between the input forces and the actual movement of the peg in the hole coordinate frame are obtained. The general strategy investigation for the robotic assembly operations for symmetric regular polyhedral objects without using force sensors is designed on the basis of the mappings and the general principles in the strategy investigation. The experiments on the precise round and triangular peg—hole systems are presented to prove the validity of the general strategies designed. The strategy of assembly operations for other symmetric regular polyhedral objects without using force sensors is presented.
Measurement and diagnostics of machine tool errors during circular contouring motions
Authors: Kwon H D , Burdekin M 
Published: October 2002

This paper deals with the measurement and diagnosis of the machine tool errors by application of the ball link bar system. It includes the development of a new link bar, the in-plane and out-of-plane measurement techniques and the machine error analysis system. The new type of ball link incorporates an idealized three-point kinematic contact principle between the balls and sockets of the link bar, and provides the following features: (a) the minimum length of the link corresponds to the minimum length of a standard LVDT transducer, (b) the link is of light weight, (c) the accuracy and the repeatability of the link corresponds to that of the LVDT (linear variable differential transformer) transducer and (d) the link is mounted between two reference balls by using the spring force of the LVDT transducer and thereby eliminating the need for magnets as in the case of the conventional double-ball bar. With the in-plane and out-of-plane measurements under different test conditions, the machine errors, such as set-up errors, closing errors, backlash errors, dynamic backlash errors, positional errors, pitch motion errors, transient errors around the start point of the test path, vibration due to too high a gain setting, stick-slip errors, squareness errors and servo mis-match errors, can be analysed by the application of the machine error analysis software. Practical measurements on the TAKISAWA CNC (computerized numerical control) machining centre were carried out and the machine tool errors were effectively evaluated.
Heat generation at photopolymerization by multiple-spot exposure with blue light
Authors: Loose K , Niino T , Nakagawa T 
Published: October 2002

In this paper, heat generation in an acrylate monomer during photopolymerization in multiple-LED photographic curing (MPC) is studied. During the exposure process, an array of multiple beams of light are projected simultaneously on to the resin surface while the projector moves across the resin vat. In this way, exposure occurs through raster scanning. It was found that the heat generated by the polymerization process causes the resin temperature to increase in steps to a maximum of 25 °C when scanning at a velocity of 0.5 mm/s. Heat from the light source itself is not induced. At 3 mm/s, excess temperature decreases to only approximately 4.5 °C. For one layer, three-dimensional temperature profiles show that excess temperature is distributed equally, perpendicular to the scan direction. The polymerization process occurs slowly. Using spectrophotometry, the course of absorbance of the photoinitiators can be observed. At 470 nm, the absorbance increases from 0.4 to 1.2 in the liquid state. The absorbance of the photoinitiators decreases to 0.1. After 30 min of exposure, the polymerization process is complete. This necessitates post-curing after the actual build process.
Design reuse: An overview
Authors: Sivaloganathan S , Shahin T M M 
Published: October 2002

This paper reviews the current research that has been carried out under the ‘design reuse’ umbrella. It classifies and discusses the work carried out in design reuse under seven categories, namely: focused innovation, cognitive studies on design reuse, computational perspective of design reuse, use of standard components, design reuse tools and methods, design reuse systems and issues in design reuse. In the light of this discussion it proposes future areas of work to enable design reuse to become an accepted tool for systematic design.
Failure analysis of mature robots in automated production
Authors: Starr A G , Wynne R J , Kennedy I 
Published: October 2002

Robot failures are costly and difficult to diagnose. Breakdown data for robot-automated production lines, collected from automotive applications, showed that nearly half of robot failures are caused by positional error. A further quarter were attributed to drive failures. Positional error may be caused by a number of mechanical failure modes or by poor tuning of the control system. Testing of repeatability or absolute position in the work place is hard because the robot moves quickly, allowing little time for measurement. Measurement may be required in up to six axes. The end-effectors of a robot, e.g. welding guns, grinding wheels and sealant applicators, are powerful and unguarded, and are not compatible with conventional contact, or close proximity non-contact, transducers. This paper presents significant new industrial evidence of the need for advanced diagnostic techniques in industrial robotics. Historical records for about 200 robots in automotive applications were analysed, identifying the major failure modes. Existing maintenance and condition monitoring methods were audited, and the problems of selecting condition monitoring methods for robots were analysed, identifying characteristics that differ from application in calibration. Measurement methods are briefly reviewed in the paper. It is concluded that non-invasive, non-contact methods are a prerequisite for operational effectiveness.
An experimental investigation of human mismatches in machining
Authors: Case K , Sinclair M A , Rani M R Abdul 
Published: October 2002

Mismatches refer to incompatibilities, inappropriateness, unsuitabilities or inconsistencies in machine operators' actions which, if not addressed, would lead to errors. A fuller understanding of the rate at which mismatches occur and their causes would allow human aspects to be given proper consideration alongside hardware and technological issues in the design of new working environments, machines and tasks. This research highlights these human aspects of machining by examining mismatches in relation to various human characteristics. The human task-mismatch matching method was developed and applied in manual turning operations using experimental and questionnaire techniques on groups of 16 skilled and 12 unskilled operators. The skilled subjects were drawn from local industry and university technical staff. Unskilled subjects were engineering students, all of whom had some familiarity with machining through periods of industrial placement. Statistically significant relationships were established between mismatches and many of the human characteristics studied (skill, age, work experience, self-confidence and trust) when considering all the subjects as a single group, but for skilled operators alone, the only significant relationship was between self-confidence and trust. As a general conclusion, it can be confirmed that studying operators in their own workplace provides invaluable information for the design and operation of future workplaces, but that the relationships between performance and human characteristics remain difficult to establish formally.
The future of aircraft propulsion
Authors: Ruffles P. C. 
Published: October 2002

The next century offers many challenges to the aero-engine industry in both the civil and the military markets. The primary driver in both markets will be to reduce the cost of acquiring, operating and supporting the product throughout its life. Reducing the environmental impact will be an additional challenge for the civil sector. Aero-engines operate at the limits of technology, take longer to develop than airframes, are often in direct competition for one such airframe and typically have an aftermarket value of up to double their initial cost. It is therefore important to place great emphasis on forecasting customer needs and future market requirements. Developments in the design of turbomachinery, combustion and control systems will offer performance, cost and environmental advantages in both the near and the long term. These developments will be aided by the progression of materials technology. The technologies applied to the product will be complemented by the technologies applied in the design, manufacture and support of products in order to reduce cost at every stage of the product life cycle. In this way the industry will continue to provide value to the customer well into the twenty-first century.
Mechanisms of fatigue crack initiation in annealed, quenched and tempered 4340 steel
Authors: Yang F , Saxena A 
Published: October 2002

The mechanisms of fatigue crack initiation in annealed and quenched and tempered 4340 steel were characterized. Several axial fatigue specimens were tested at a strain range of 1.5 per cent to various fractions of fatigue life. The tested specimens were thoroughly examined using a scanning electron microscope (SEM) and an atomic force microscope (AFM). The latter technique provides a better resolution and is also capable of providing quantitative surface topographical information. In annealed 4340 steel, the initial fatigue damage is shown to accumulate in the form of steps between ferrite and cementite laths in the pearlitic microstructure. Subsequent damage accumulation occurs by formation of slip bands which are formed by joining several adjoining steps. Cracks initiate from the slip bands. In quenched and tempered steels, the fatigue damage accumulates at discontinuities at a more rapid rate than in the remaining regions of the specimen, leading to crack initiation and growth emanating primarily from the discontinuities. The roughness of the specimen surface increases with fatigue damage in both microstructures, as demonstrated from the measurements obtained from AFM studies. Such correlations may be useful in predicting the remaining life of cyclically loaded structural components.
Measurement of the stiffness of joints in a graphite brick assembly
Authors: Robinson A M , Drinkwater B W , Dwyer-Joyce R S , Payne J F B 
Published: October 2002

Large, dry-contacting assemblies of graphite blocks are a feature of many nuclear reactors, and the seismic response of these structures is dependent on both the bulk and surface properties of the blocks. The nature of the interblockinterface will influence the load-deflection relationship of the blocks, which is important in understanding the response of the structure to seismic loading. The stiffness of this interface is dependent on surface roughness effects. In this paper, ultrasonic reflection coefficient measurements are used to investigate the stiffness distribution of this interface under various loading conditions. A low-frequency quasi-static spring model of the interface was adopted. This allowed the interfacial stiffness to be determined as a function of applied load, frequency, surface roughness and graphite composition. Cyclical loading of the graphite-graphite interface has also been carried out. This has shown that there is only a slight plastic deformation under normal loading, and also is indicative of a degree of intersurface adhesion at the interface. Direct measurement of the load-deflection relationship of an entire brick was also carried out which, in conjunction with the ultrasonic measurements, suggests that it is the effect of macroscopic surface features rather than microscopic roughness that is the dominant interfacial contribution to brick-tilting stiffness.
Direct evidence of lubrication in ceramic-on-ceramic total hip replacements
Authors: Smith S L , Dowson D , Goldsmith A A J , Valizadeh R , Colligon J S 
Published: October 2002

A study of surface contact and separation of ceramic-on-ceramic joints was undertaken in 25 per cent bovine serum using a hip simulator. An electrical resistivity technique was used to detect the extent of surface separation throughout a complete walking cycle. The femoral and acetabular components were coated in a thin conducting film of titanium nitride to allow application of the resistivity technique to non-conducting ceramic. Surface separation of the acetabular and femoral components was detected throughout each simulated walking cycle. Fluctuations in the applied voltage across the joint were observed which could not be attributed to elastohydrodynamic or squeeze-film lubrication effects. The probable cause of the voltage fluctuations was brief and occasional contact between the surfaces caused by a combination of asperity contact and subsequent detachment of the conductive coating.
Contact between a centrally loaded plate and a rigid or elastic base, with application to pivoted pad bearings
Authors: Kauzlarich J J , Greenwood J A 
Published: October 2002

Coker and Filon first introduced the idea that the contact area between a pad and a support may decrease under the application of a load, the process subsequently called a ‘receding contact’ by Keer et al. Filon analysed the contact between two matching slabs under a line load, and showed that, for the two to remain in contact, the mid-plane contact stresses must change from compression to tension beyond a distance from the line load of approximately 1.35 times the slab thickness. Filon argued that, since the tensile stresses are small, in a real contact the two slabs will separate at approximately these locations. A photoelastic study by Frocht of the stress pattern when a line load acts through a pad resting on an elastic base supported Filon's prediction. It is shown by a three-dimensional finite element (FE) solution for the axisymmetric load problem that the radius of separation on a rigid base is significantly smaller than that calculated using the Filon assumption. When the pad is supported on an elastic base of the same material, the same is true, though both radii are significantly larger than with the rigid base. The results are applicable to several practical problems. For a rigid base, examples are two slabs pressed together by circular dies, and the initial geometry in resistance spot welding. The case of an elastic base is of wide application in civil engineering, when a pillar is supported on a bearing plate on an elastic base. In tribology it may explain the start-up under load of a centrally pivoted thrust pad bearing, which otherwise must rely on surface tension to retain a residual oil film.