bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface integrity of hard-turned M50 steel
Authors: Jacobson M
Published: October 2002

The purpose of this paper is to examine how the surface integrity of M50 steels is affected by hard turning. Tests were conducted on a lathe using different tools and depth of cut. The surface was evaluated in terms of residual stress, surface roughness and microstructure analysis. The tests showed that hard turning provides good surface integrity. The effect of tool parameters and depth of cut on residual stress was investigated in order to find how the residual stress could be altered. It was found that effective rake angle and tool nose radius both affected the residual stress generated. The surface roughness of the hard-turned test samples followed the theoretically calculated values. The surface of the test samples showed no alteration to the microstructure. On the basis of the results it can be concluded that hard turning of M50 steel is a suitable manufacturing process. One possible application for this process is the manufacturing of a main shaft bearing for an aero-engine.
A comparison of temperature reduction in high-pressure jet-assisted turning using high pressure versus high flowrate
Authors: Dahlman P
Published: October 2002

Cooling with high pressures in turning operations is an effective method for providing higher productivity. Reduced temperature and improved chip control are dependent on the pressure and flowrate of the fluid jet. The aim of the tests was to investigate how the relationship between pressure and flowrate affects the heat dissipation from the cutting zone. Tests were performed on two steel grades and one titanium alloy, allowing the same jet momentum for all materials to enable comparison between pressure and flow. Conventional cooling was used as a reference. Measurements were conducted with thermocouples attached to the clearance face of the tool. The temperature was generally reduced by approximately 50 per cent when high-pressure cooling was applied compared with conventional cooling. The results show that different pressure and flow relationships have a small but significant influence on heat dissipation from the cutting zone for the steel materials. Results show that it is important to have the right combination of pressure and flow in order to achieve optimum temperature reduction. Materials with a higher ductility benefit more from a higher flowrate while materials with a lower ductility require higher pressure. The same jet momentum was used in both cases.
Engineering process management (EPM)—with Intranet support to innovative products
Authors: Eversheim W , Schröder J , Bauernhansl T
Published: October 2002

Intranet-based methods and tools provide support to product development processes. Effectiveness (‘doing the right things’) is increased with the ‘PORTAL’ method by evaluation and selection of new project ideas. Efficiency (‘doing the things right’) is ensured by the Intranet-based product development manual and the included methods database supporting management of the selected product development projects.
Recognition of pass features for automatic parting surface generation in injection moulds
Authors: Chung K , Lee K , Kim T
Published: October 2002

This paper proposes a topology-based algorithm for recognizing passage features using the concept of a multiface hole loop. The multiface hole loop is a conceptual hole loop that is formed over several connected faces and serves as an entrance or an exit of a passage. A passage feature is thus recognized by identifying two multiface hole loops corresponding to its entrance and exit. To generate the core and the cavity of an injection mould for a part with passage features, either the entrance or the exit of each passage must be covered by a surface, and this surface constitutes the parting surfaces. The algorithm proposed in this paper checks the connectivity of the two multiface hole loops to recognize passage features. The total number of passage features in a part is calculated from the Euler equation, and the identification procedure continues until the number of identified passage features equals this number. To find all of the multiface hole loops in a part, the proposed approach considers all of the combinations of connected faces. The edge convexity is used to judge the validity of multiface hole loops. By using the algorithm proposed in this paper, the passage features could be recognized effectively. The approach proposed is illustrated with several example cases.
Optimizing resources: Assessment of manufacturing practice
Authors: Davidson J C , Williams A
Published: October 2002

Two case studies are presented from within the plastics industry. The studies investigate the feasibility of optimizing resources using traditional manufacturing metrics. A data capture framework is presented, which represents pre-, intra- and post-production processes, and both internal and external perspectives on manufacturing and the use of facilities. The paper concludes with an assessment of the findings and of the potential for wider implementation of the framework within manufacturing industries.
The sharpness of grinding wheels: An important measure of grinding behaviour
Authors: Chen X
Published: October 2002

This paper aims to make a clearer picture of the sharpness of grinding wheels in terms of the wheel performance in grinding. It was found that the system time constant is the most sensitive to any change in wheel dressing operation, which has strong effects on the wheel topography. The effects of dressing conditions were investigated together with the grinding conditions. Some control strategies for improvement of the grinding operation by considering wheel sharpness are presented in the paper.
Precision rapid mould by transferred coating
Authors: Shan Z , Yan Y , Zhang R , Liang J
Published: October 2002

The technique of precision rapid mould by transferred coating forming is an innovative rapid tooling (RT) process. It combines many techniques such as transferred coating and rapid prototyping. The main advantages of this process compared with other RT processes are low investment and production cost, shorter production cycles and many kinds of scale tool. The manufacturing process and the coating materials have been researched. The results of application show that net shape production may be fabricated in 2–7 days. The surface roughness of tools, Ra, can reach 1.6–6.3 äm, and dimensional accuracy may attain CT4-CT6.
Instability phenomena in the gas—metal arc welding self-regulation process
Authors: Bingül Z
Published: October 2002

Arc instability is a very important determinant of weld quality. The instability behaviour of the gas-metal arc welding (GMAW) process is characterized by strong oscillations in arc length and current. This phenomenon was reported by Halmoy [1] for the short electrode extension and by Lebedev [2] for the long electrode extension, particularly as related to the arc voltage-current characteristics and the thermal inertia of the electrode wire respectively. However, with these studies, a complete theoretical explanation of the instability phenomena is lacking since the process is not modelled dynamically.

In the present work, a model of the GMAW process is developed using an exact arc voltage characteristic. This model is used to study stability of the self-regulation process and to develop a simulation program that helps to understand the transient or dynamic nature of the GMAW process and relationships among current, electrode extension and contact tube-work distance (CTWD). The process is shown to exhibit instabilities at both long electrode extension and normal extension. The experimental results agree closely with both Lebedev's and Halmoy's results. Results obtained from simulation runs of the model were also experimentally confirmed by the present author, as reported in this study. In order to explain the concept of the instability phenomena, the metal transfer mode and the arc voltage-current characteristic were examined. Based on this examination, the conclusion of this study is that their combined effects lead to the oscillations in arc current and length.
Wear evaluation of a self-propelled rotary tool when machining titanium alloy IMI 318
Authors: Ezugwu E O , Olajire K A , Wang Z M
Published: October 2002

This paper presents results of a self-propelled rotary tool (SPRT) tipped with round uncoated carbide (WC-Co) inserts in the finish turning of titanium alloy IMI 318. SPRT inserts exhibited superior wear resistance to conventional round and rhomboid-shaped carbides as well as to the rhomboid-shaped physical vapour deposition (PVD) TiN-coated carbide inserts owing to the distribution of the cutting energy along the entire tool edge. The SPRT-tipped inserts suppressed thermally related wear mechanisms at higher speeds beyond the capability of conventional tools. Chipping was the dominant failure mode of the SPRT inserts, resulting from cyclically fluctuating thermal and mechanical shocks induced by the continuous shifting of the cutting edge during machining. A fitted exponential wear model revealed that about 97 per cent of the average flank wear rate of SPRT inserts can be attributed to the joint effect of speed, feed and inclination angle, ε. Tool performance was improved by increasing the inclination angle ε which resulted in a lower machining temperature on account of a higher rotary speed and a lower relative cutting speed during machining. Lower component forces were recorded with SPRT inserts because of the reduced amount of work done in chip formation and lower friction at the rake face.
Touch probe radius compensation for coordinate measurement using kriging interpolation
Authors: Mayer J. R. R. , Mir Y. A. , Trochu F , Vafaeesefat A , Balazinski M
Published: October 2002

Obtaining CAD (computer aided design) descriptions of actual parts having complex surfaces is a key part of the process of reverse engineering. This paper is concerned with the estimation of actual surfaces using coordinate measuring machines fitted with a spherically tipped touch probe. In particular, it addresses in detail the problem of probe radius compensation. A general mathematical model, using kriging, is proposed which first generates the initial probe centre surface and then estimates the compensated or part surface. The compensation is achieved using normal vectors to the initial probe centre surface at each measured point to compensate for the probe radius. The method is validated experimentally on known and free-form surfaces.
Experimental investigation and finite element modelling in gravity die casting
Authors: Anderson J T , Gethin D T , Lewis R W , Cross J T
Published: October 2002

A combined experimental model for a gravity die casting is presented. The experiments were shown to yield consistent results and confirmed earlier studies, which showed that interfacial heat transfer depends on the casting solidification state and that only its maximum value is affected by die coat thickness. The numerical model was found to capture the thermal transients when interface effects were included and when the removal of cores was accounted for in the analysis. To reflect this process, an integrated cyclic analysis is demonstrated capturing the thermal behaviour during fill, solidification and die open stages in the casting cycle.
Determination of finishing features in 2½ D components
Authors: Xu X , Hinduja S
Published: October 2002

This paper describes a fuzzy decision system which examines the tolerances and surface finish associated with each face of a component and determines the number and type of operations required. The types of operations considered are finishing, semi-finishing and roughing. Using a backward chaining approach, elementary finishing volumes are generated for each face and these elementary volumes are then suitably combined to form finishing/semi-finishing features. These features are glued to the component to give the intermediate shape of the workpiece and it is this workpiece that is used for recognizing the roughing features. An example is included to illustrate the methodology.
The analysis of CO2 laser cutting
Authors: Yilbas B S
Published: October 2002

The laser finds increasing commercial use as a cutting tool. The laser cutting quality characteristics require microscopic evaluation of the resulting cut properties. Striation is considered as one of the important quality characteristics and its formation is strongly related to cutting and workpiece parameters. However, the mechanism of formation of striations has not yet been well established. To enhance the understanding of striation and its properties, the present study is conducted. A mathematical model relevant to formation of striation is developed, and striation width and frequency are predicted. In the model a heat transfer equation employing a moving heat source and allowing a chemical reaction contribution to available power at the workpiece surface, due to an assisting gas effect, is introduced. The study is extended to include experimental investigation into the striation process. Consequently, striation frequency and striation width are measured using the microphotography technique and a fibre-optic probe. It is found that the mathematical model introduced represents the physical phenomena well, with the limits of characteristic distance, striation frequency and striation width, as predicted, agreeing well with the experimental findings.
Temperature changes in hot flat rolling of steels at low strain rates and low reduction
Authors: Aiyedun P O , Sparling L G M , Sellars C M
Published: October 2002

A finite difference (two-dimensional) model developed to describe the heat flow at low strain rates (0.08–1.5 s−1) and low reduction (∼10 per cent) for a hot flat rolled slab both during air cooling and during roll contact has been used in conjunction with experimentally measured temperatures through specimen thickness during roll contact after reheating to temperatures in the range 1000–1200°C for mild steel, low carbon SS316 and high carbon SS316 (with Nb, V and Ti).

At high strain rates (∼1.5 s−1) a steep temperature gradient was produced in the specimen near the surface whereas for low strain rates (∼0.08 s−1) this temperature gradient penetrated deep into the thickness, leading to a large drop in the mean rolling temperature.

Roll chilling, leading to higher values of the Zener-Holloman parameter, Z, resulted from a decrease in the mean rolling temperature and the large temperature gradient during roll contact. Temperature changes due to material composition, reheating temperature, contact time and rolling conditions led to precipitation strengthening and roll chilling effects which have accounted for the excess load and torque observed experimentally and industrially.
Acoustic emission monitoring of tool wear during the face milling of steels and aluminium alloys using a fibre optic sensor. Part 1: Energy analysis
Authors: Carolan T A , Kidd S R , Hand D P , Wilcox S J , Wilkinson P , Barton J S , Jones J D C , Reuben R L
Published: October 2002

An investigation of the relationship between tool wear and the energy of acoustic emission (AE) produced during various face milling finishing operations is presented. A model detailing how the AE energy, quantified by the r.m.s. value, varies depending on the material and the detailed tool geometry formed by flank and crater wear is described. Validation of the model was achieved in a series of practical machining tests covering a range of materials and tool types which resulted in various different wear forms. In all these wear tests a non-contact fibre optic interferometer was employed for AE detection directly from the workpiece. This sensor makes absolute, calibrated measurements of AE, unlike conventional contacting piezoelectric AE transducers, which may suffer uncertainties due to their frequency response and variations in transmission path. The fibre optic instrument is thus advantageous for studying variations of AE energy with tool wear.
Investigation on arc light intensity in gas metal arc welding. Part 1: Relationship between arc light intensity and arc length
Authors: Yoo C D , Yoo Y S , Sunwoo H-K
Published: October 2002

The arc length has been detected through the arc because the welding current and voltage vary linearly with the arc length. In this work, the relationship between the arc light intensity and arc length is investigated through analytic modelling. The arc light intensity is derived as a function of the arc length and welding current using the heat balance in the plasma. Experiments are carried out to verify the proposed model and to find out the effects of welding conditions on the arc light intensity in gas metal arc welding (GMAW). The arc light intensity varies proportionally to the arc length and signal quality is enhanced with a fast weaving speed. The predicted results of the arc light intensity show reasonably good agreement with the experimental data.
Design capability and the costs of failure
Authors: Swift K G , Raines M , Booker J D
Published: October 2002

In this paper, recent advances in the analysis of products for assessing the consequences of design decisions on quality of conformance are presented. The approach, called conformability analysis, uses estimates of likely process capability levels and likely failure severity to approximate the costs of failure in production and service, associated with non-conforming design characteristics. Improvements in estimating process capability are discussed and the correlation between the estimated values and shop-floor capability levels is reported. A case study is employed to illustrate how the analysis can be used in new product development and the benefits that may accrue from its applications.
Software for the rapid production of patterns for castings
Authors: Huang Y S , Webster P D , Dean T A
Published: October 2002

This paper describes a system that enables the automatic conversion of information from a computer aided design (CAD) pattern representing a three-dimensional (solid) concept directly into a physical part. By integrating this information with computer-controlled machine tools, invoking concurrent validation with simulation to optimize cutting procedures and utilizing a novel machining-casting-machining technique, products can be developed quickly with little human intervention, reducing delays typically found between the design and manufacturing processes.
Investigation into hydromechanical reverse redrawing assisted by separate radial pressure—process development and theoretical verification
Authors: Kim J B , Lee D W , Yang D Y , Park C S
Published: October 2002

High-quality cups with a deep drawing ratio of more than four cannot be simply drawn by conventional drawing and redrawing. A special technology is required to form cups of a high deep drawing ratio. In the present study, after the conventional mechanical deep drawing process, subsequent hydromechanical reverse redrawing with controlled radial pressure has been developed. In order to increase the deep drawing ratio by more than four, the radial pressure is controlled independently of the chamber pressure and thus an optimum forming condition can be determined by varying the radial pressure.

The process has been verified by a rigid-plastic finite element (FE) analysis considering all the external force boundary conditions induced by the hydrostatic pressure. The pressure distribution on the sheet is calculated numerically from the simplified Navier-Stokes equation. Through the experiment and the FE analysis, it has been shown that hydromechanical reverse redrawing assisted by separate radial pressure, developed in the present study, helps to increase the drawability of cylindrical cups, and thus it is useful when forming long cups.
Measuring the performance of product introduction
Authors: Brookes N J , Backhouse C J
Published: October 2002

This paper begins with a discussion of the importance of the effective performance measurement of product introduction and the difficulties inherent within that task. Criteria are then established for effective product introduction performance measures which are used to identify the most appropriate of existing performance measurement mechanisms. A case study approach of industrial organizations is used to examine whether this mechanism is employed in practice, and wider conclusions are drawn on the formation of effective measures of performance for product introduction.
Analysis and modelling of reactive three-dimensional high-power CO2 laser cutting
Authors: Chen S-L
Published: October 2002

A model of the process of cutting metal with a gas assisted CO2 laser beam has been derived with the principal objective of understanding the role of manufacturing parameters both from its kinetics and its chemistry. The model considers the cutting front as a surface phenomenon for reaction and absorption. An adjusting parameter, m, is introduced in this model to represent the absorptivity for different materials and different incident angles. The mass diffusion rate at the gas/solid boundary of the cutting front is included in this model to investigate the exothermic heat which will be released at the cutting front during the cutting process. The effects of oxide films, polarization, cut front shape, cutting speed and laser power have been analysed. The tendency of the experimental results from many previous researchers agrees with the prediction of these theoretical results. It is shown that very small levels of impurity in the oxygen would be expected to have a significant effect on the cutting performance.
An auxiliary approach to the experimental study on chip control: A kinematically simulated test
Authors: Fang N
Published: October 2002

Traditionally, cutting tools made of sintered carbides or high-speed steels are used to cut a variety of metal materials in the experimental study on chip control. One of the existing problems is that, in most cases, it is difficult to make, in a laboratory, cutting tools with a three-dimensionally shaped chip breaking groove for use in the follow-up experiments. Turning to tool manufacturers, who use the powder metallurgy techniques of tool making for help, usually leads to a long experimental period and high cost. An auxiliary approach to the experimental study on chip control, called a kinematically simulated test (KST), is proposed in this present work to overcome the above shortcoming of the traditional method employed in the experimental study on chip control. A plexiglass-made cutting tool is employed to cut a commercially available paraffin wax to simulate some kinematic phenomena (such as chip flow and chip curl) which take place during practical machining processes. After the applied range of KST has been illustrated, two examples of applying KST are given. One is the application of KST to chip flow research. The other is optimizing the geometry of the chip breaking groove of a tool insert by means of KST. Both examples involve the making of the chip breaking grooves with the three-dimensional shape and geometry.
Machining nickel base superalloys: Inconel 718
Authors: Choudhury I A , El-Baradie M A
Published: October 2002

A series of machining experiments of Inconel 718 has been carried out using coated and uncoated carbides. The paper describes the effects of cutting variables (speed, feed and depth of cut) on cutting forces and tool life. Carbide tools in the form of 80° rhomboid shaped inserts without any chip breaker have been used at different cutting conditions. The machining parameters have been optimized by measuring cutting forces. Flank wear was considered as the criterion for tool life. A comparison between the uncoated and coated tools has been made using the Taylor's tool life exponents of speed, feed and depth of cut. The tool life of coated tools was not found to be better than that of the uncoated tools.
A robust in-process monitoring of pulsed laser spot welding using a point infrared sensor
Authors: Lim D-C , Cho Y-B , Gweon D-G
Published: October 2002

Many manufactured goods employ pulsed laser spot welding in joining and it is important to monitor the weld quality. The weld quality is highly related to the thermal history of the weld and there have been many trials to monitor the quality using an infrared (IR) sensor. Though the emitted thermal radiation is a function of the emissivity and the surface temperature, the measuring condition has an important influence on the detectable radiation. To increase the reliability of monitoring, it is useful to find the robust feature that is immune to the change of measuring condition. This paper suggests an in-process monitoring method using a point IR sensor for the pulsed laser spot welding of thin metal sheet. The suggested monitoring method is robust to the change of the measuring condition and it can detect the variation of the absorbed energy as well as any serious defect in the weldment.
Knowledge-based systems approach to the development of accurate and realistic master production schedules
Authors: Kochhar A K , Ma X , Khan M N
Published: October 2002

In today's dynamic and highly competitive market environment, the ever changing customer requirements often destabilize master production schedules. It is often necessary to analyse the effects of any changes in quantities, priorities, due dates, etc., in a timely manner and incorporate them into a revised master production schedule which must continue to be realistic and achievable. This paper describes the design and application of a knowledge-based system that can be used to help with the creation, testing and finalization of accurate and realistic master production schedules. The system can test the validity of a tentative master production schedule or evaluate the effects of any changes in an existing one with the aim of identifying any bottlenecks that will prevent its actual achievement. With the effective use of what-if analysis and simulation techniques, the system makes it possible to consider all of the alternative solutions and take due account of the operational and business realities of the environment. Therefore, the management can choose, over a short period of time and in an interactive manner, the best possible solutions to the problems of a given master production schedule.
Determining the distribution of the heat content of filler metal droplets transferred into gas—metal arc weld pools
Authors: Wu C S , Sun J S
Published: October 2002

The distribution of the heat content of filler metal droplets inside the gas—metal arc (GMA) weld pool has a marked effect on the weld bead dimensions and the weld thermal cycle. A model is developed to account for this distribution. Volumetric distribution of the heat content of droplets within the weld pool is considered as an internal heat generation term. Based on physical reality, an algorithm is proposed to determine the geometry and size of the volume within which the heat content of droplets is distributed. Bead-on-plate GMA welding experiments show that the predicted weld dimensions and temperature variations are in agreement with the measured values.
Intelligent optimization of grinding processes using fuzzy logic
Authors: Vishnupad P , Shin Y C
Published: October 2002

This paper presents a generalized intelligent grinding advisory system (GIGAS) for the optimization of the following three grinding processes: straight-cut surface grinding, internal and external cylindrical plunge grinding. The framework of GIGAS is based on model-based fuzzy logic. The main feature of GIGAS is that it can interactively accept several different process models pertaining to a specific grinding process, as well as heuristic rules. To this end, it uses generalized process models for the grinding force, the grinding power, the maximum chip thickness, the surface roughness, the grinding ratio, the effective dullness of the wheel and the grinding temperature. The scheme allows the user to change interactively the process models used by GIGAS for optimization and hence can accommodate a large number of grinding conditions. It is also demonstrated that accurate solutions can be obtained in the order of several seconds using fuzzy inferencing, thereby showing the possibility of real-time control. The performance of GIGAS is tested in comparison with a known conventional method of optimization of the internal cylindrical plunge grinding process.
The use of thermal imaging, temperature and distortion models for machine tool thermal error reduction
Authors: Postlethwaite S R , Allen J P , Ford D G
Published: October 2002

Research has shown that up to 75 per cent of the total machining error can be produced by thermal distortion. Thermal error compensation can provide an attractive solution to this accuracy problem. Research has shown that thermal error compensation can reduce thermal errors to an acceptable level, but the techniques adopted have had inherent disadvantages that make them impractical for general use. This paper describes a novel indirect measurement based thermal error compensation technique that overcomes the main difficulties of applying thermal compensation, making it practical and generally applicable. The technique makes extensive use of thermal imaging for rapid assessment of machine tool thermal behaviour and off-line development of the compensation models. To illustrate the use of the technique it is applied to the head slide of a vertical machining centre.
A close look at the rough terrain of surface finish assessment
Authors: Radhakrishnan V , Weckenmann A
Published: October 2002

Diminishing tolerances, enhanced reliability and the need for predictable life-spans for products have emphasized the significance of surface finishes of manufactured parts. Over the years, there has been a considerable amount of development in this area. A variety of instruments, a good number of finish parameters and volumes of research have all enhanced the knowledge base. More recently, with the availability of advanced instruments, the focus is gradually shifting to the three-dimensional evaluation of surfaces. Practising engineers are keen to have solutions to problems connected with finish assessment. If past experience in this field is any lesson, there are many challenges that have to be overcome to arrive at a workable solution, which could satisfy the design and manufacturing engineers as well as researchers in this field. This paper examines these aspects in a brief fashion.
Application of stochastic real-valued reinforcement neural networks to batch production rescheduling
Authors: Heywood M I , Chan M-C , Chatwin C R
Published: October 2002

This paper details the design and application of a hybrid neural network architecture for the rescheduling problem of batch manufacture. Design issues include the selection of an appropriate neural network paradigm, specification of the network architecture and support for multistep prediction. Application issues include decoupling the network dimension from that of the problem and the definition of suitable rescheduling operators. The ensuing hybrid network is tested against heuristics previously identified as typically representing estimates for best and worst case performance within a cross-section of batch rescheduling problems.
Electric discharge milling of polycrystalline diamond
Authors: Liu Y H , Guo Y F , Liu J C
Published: October 2002

Polycrystalline diamond (PCD) has been used widely in modern industry. However, the manufacture of PCD blanks is not an economical and efficient process. The shaping of PCD blanks with conventional machining methods (such as grinding), is a long, labour-intensive and costly process. Electromachining processes promise to be effective and economical techniques for the production of tools and parts from PCD blanks. Wire electric discharge machining is able to effectively slice PCD. Electrical discharge machining (EDM) and electrical discharge grinding (EDG) shape PCD blanks at a lower cost. However, EDM and EDG of a large surface area on PCD show lower efficiency. This paper presents a new process of machining PCD using electrical discharge (ED) milling. ED milling employs a DC source instead of the pulse generator used in EDM, and uses a water-based emulsion as the machining fluid. This process is able to effectively machine a large surface area on PCD, and effectively machine other advanced conducting materials such as cubic born nitride (CBN), and ceramics. The effect of pulse on-time, peak current, and polarity on the process performance has been investigated.
Computer aided modelling of the human spine
Authors: Case K , Xiao D C , Acar B S , Porter J M
Published: October 2002

The human spine is the main structure to support human body weight and external loads, to allow the torso to reach to a variety of positions and to protect the spinal nervous system. Lumbar back pain and disorders may be related to spinal curvature and disc pressure, and it is an ultimate objective of the work reported here to include consideration of these issues in computer aided ergonomics design systems for evaluating a wide range of situations including manual handling and car seat design.

Several methods from structural analysis have previously been used to model the human spine, principally lever and beam structures, but these have frequently shown discrepancies when compared with experimental data. As an alternative, an arch representation for the spine is considered here and allows the establishment of a criterion for the failure of the spine that may be useful in determining absolute maximum loading conditions. However, the main interest is in submaximal loading conditions where damage or discomfort are the concerns rather than fracture. It is proposed that the location of the thrust line in relation to the centre-line of the spine is a useful predictor, and optimization techniques have been developed to find the ‘best-fitting’ thrust line for the statically indeterminate structure.

Further work is concerned with adding muscle and ligament forces to the loading system of the model, extension of the two-dimensional model into three dimensions, validation against experimental data and integration with the SAMMIE computer aided ergonomics design system.
Modelling surface roughness improvement in grinding
Authors: Chen X , Rowe W B
Published: October 2002

Grinding is a precision machining process used to improve workpiece surface roughness. This paper demonstrates that spark-out is the most important stage of a plunge grinding cycle for achievement of a low value of roughness. The nature of the spark-out process is investigated including the effects of machine stiffness, system deflection, wheel sharpness and plastic deformation on improvement of surface roughness. Experiments and a comparison with predictions from a computer simulation programme demonstrate the effects of the fundamental factors. It is demonstrated that the time constant for roughness is more than twice the time constant for system deflections.
A system for automatic extraction of feature-based assembly information
Authors: Pham D T , Dimov S S
Published: October 2002

This paper describes a system for analysing three-dimensional assembly models and extracting assembly related data. These data can be used for identification of part interdependencies in complex assemblies and for automatic generation of assembly strategies.
A manufacturing model representation of a flexible manufacturing facility
Authors: Molina A , Bell R
Published: October 2002

The manufacturing model is an information model that describes the manufacturing capability of a particular enterprise. To achieve general applicability, the model consists of the entities that are relevant and important for any type of manufacturing firm, namely: manufacturing resources (e.g. machines, tools, operators, etc.), manufacturing processes (e.g. machining processes, assembly, etc.) and manufacturing strategies (e.g. how these resources are organized and used). The manufacturing model is a four-level model based on a de facto standard (i.e. factory, shop, cell, station) that represents the functionality of the manufacturing facility of any firm. The manufacturing model concept presented in this paper represents the manufacturing capability of a high-performance flexible manufacturing facility.
Improving wood surface form by modification of the rotary machining process—a mechatronic approach
Authors: Brown N , Parkin R M
Published: October 2002

Rotary machining is extensively used for planing and moulding operations within the woodworking industry. Although the surface form produced by this machining method is acceptable, the rotary machining action produces cutter marks on the wood surface so that further finishing operations, such as sanding, are often required to generate a product of acceptable standard. It has been theorized that the surface finish of planed and moulded timber products may be improved by oscillation of the cutter block in either a vertical or horizontal plane. This paper describes the use of a rapid surface simulation algorithm to predict surface finish and the use of computer simulation to model cutterblock oscillation. The result is a tool for effective design and optimization of a hydraulic oscillation system in order to improve surface form.
Multipass machining optimization by using fuzzy possibilistic programming and genetic algorithms
Authors: Alberti N , Perrone G
Published: October 2002

The paper deals with optimal determination of the cutting parameters in multipass machining operations. A new optimization approach is proposed which uses a possibilistic formulation of the classical optimization problem and optimizes the resulting possibilistic model using a genetic algorithm. The proposed approach makes it possible to find the optimal value of all the cutting parameters, including the depth of cut, in just one step. A numerical example is provided to compare the performance of the proposed method with other recent methods proposed in the literature. Furthermore, fuzzy data must be used in the formulation of the optimization problem and therefore a fuzzy possibilistic approach is suggested. Solution of the proposed fuzzy possibilistic optimization problem has been approached by using fuzzy modalities and genetic algorithms.
The use of design methods within production machinery companies
Authors: Gouvinhas R P , Corbett J
Published: October 2002

This paper presents a review of how production machinery companies typically develop their products and also investigates the perceived views of typical designers within this sector with regard to the utilization of formal design methods. This analysis is based on an extended visit to a production machinery company and a series of one day visits to other companies followed by an extensive questionnaire survey. The results have indicated that production machinery companies tend to control their product development process through regular design review meetings and, in general, the level of awareness and utilization of formal design methods is very low. A series of ‘roadblocks’ that are responsible for the avoidance of more widespread use of formal design methods within these particular companies has also been identified. The subject of ‘formal design methods’ created much interest from a significant number of those who responded to the questionnaire. It is concluded that there is a demand within production machinery companies for training and the development and implementation of new and:or existing design procedures that are specifically applicable for production machinery companies.
Emulator technology in engineering design
Authors: Wynn H P , Bates R A
Published: October 2002

Emulator technology is the methodology that replaces simulators in engineering design by surrogate models, sometimes called meta-models. The methodology has three distinct stages: data capture, modelling and optimization. Space-filling experimental designs are used to gather information; then specialized adaptive models, derived from statistical principles, are used to emulate the system. The advantage of emulators is that they run many times faster than the simulators, which means they can be used in multi-domain environments for multi-objective optimization. This is generally not possible using the simulators themselves due to the computational burden. Emulator technology should be considered as part of the general data-capture and modelling environment within industry.
Rapid prototyping based on image information in reverse design applications
Authors: Peng Q-J , Loftus M
Published: October 2002

Rapid prototyping (RP) techniques have revolutionized traditional manufacturing methods. These techniques allow the user to fabricate a part directly from a conceptual model before investing in production tooling. However, significant time is required to complete the geometric modelling stage. This paper describes the development of an image-based rapid prototyping approach which can be used to generate geometric models in reverse design applications. The method, which uses standard two-dimensional photography, integrates the Torrance-Sparrow illumination model and the photometric stereo technique. A neural network approach is employed to decide the illumination parameters and the solution of the model. A range of examples has shown this method to be feasible and efficient to support the RP applications.
Application of a generic manufacturing planning and control system reference architecture to different manufacturing environments
Authors: Howard A , Kochhar A , Dilworth J
Published: October 2002

This paper describes a generic reference architecture for a manufacturing planning and control (MPC) system, which is tested in the context of the functional specification of MPC systems in medium-sized batch manufacturing companies. While the proposed reference architecture is an adaptation of the manufacturing resource planning (MRPII) model, it can also represent other approaches such as multilevel finite capacity scheduling and hybrid systems incorporating pull control (e.g. kanban). Furthermore, it is not as functionally rigid as the MRPII approach and can support the development of manufacturing planning and control systems to support the identified business processes. It is shown how the reference architecture can be used to represent companies who operate very different MPC approaches. It is also shown that the architecture can support different projects (i.e. business process re-engineering, performance measurement and the implementation of computerized MPC systems). Field tests demonstrate that the architecture is generic, has a broad application, yet is detailed enough usefully to represent the functionality of a suitable MPC system in individual manufacturing environments.
Plywood image segmentation using hardware-based image processing functions
Authors: Pham D T , Alcock R J
Published: October 2002

In the manufacture of plywood, it is necessary to inspect the veneer sheets for surface defects. The high production speeds involved call for automated visual inspection. This paper presents a new automated method for finding surface defects in images of wood veneer. The method is accurate, executes quickly and employs standard hardware-based image processing functions.
Metrics in the engineering design process
Authors: Cooke J A , McMahon C A , North M R
Published: October 2002

Ever increasing competition is forcing engineering companies to look closely at their processes to identify ways of reducing cost and increasing quality. In the manufacturing process, in particular, this has led to the widespread use of metrics for performance measurement. Companies are also looking to their design processes for performance improvement through the use of concurrent engineering and other quality techniques, but the application of metrics to this area is difficult and has been limited, in the main, to measures of performance against programme rather than of design quality. This paper suggests that an important measure of design quality is the level of unnecessary rework present in the design process. The paper presents a method for assessing rework through the use of metrics that, most importantly, identify how design quality may be improved.
Geometrical tolerancing in process planning: A tridimensional approach
Authors: Legoff O , Villeneuve F , Bourdet P
Published: October 2002

A method to perform tridimensional analysis and tridimensional synthesis of machining tolerances is presented. The model relies on the small displacement torsor concept and on the computer aided tolerancing approach. The link between process planning and functional tolerances with torsor chains according to workpiece set-ups is exposed. An example shows how the model is used to determine automatically geometrical variations of the workpiece knowing geometrical variations of each part (part-holder, positioning devices, machined surfaces, etc.).
A prototype constraint-based system for the automation and optimization of machining processes
Authors: Gayretli A , Abdalla H S
Published: October 2002

This paper presents an intelligent design system that enables designers to consider at the early stages of the design process all issues associated with the product life cycle. The evaluation and optimization of machining processes are among the most important aspects of these issues, requiring the involvement of various types of information from the different aspects of the product life cycle. The representation of this information in efficient format is very important for carrying out different design tasks. In order effectively to manage information exchange within different design and manufacturing domains, it is necessary to provide an efficient and timely communication network system. Therefore, various critical tasks such as overall coordination, control, consistency and data integrity have to be considered in order to avoid costly design iterations. This research article has focused on the development of a prototype system for machining process optimization.

The system uses a combination of both mathematical methods and constraint programming techniques and provides designers with the evaluation and optimization of feasible machining processes in a consistent manner at the early stages of the design process. As a result, unexpected and costly design iterations, which result in wastage of a great amount of engineering time and effort, and in a longer lead time, can be avoided.

The development process has passed through four major stages. Firstly, an intelligent constraint- based design system for concurrent product and process design, including a machining process optimization module, has been developed. Secondly, the product features, processes, cost, time and requirements have been represented in the format of constraints, frames, objects and production rules in order to be utilized to accomplish different design tasks. Thirdly, rules for the selection and optimization of feasible processes for complex features have been written, and finally, an information management system, with a conflict resolution mechanism, has been developed to achieve consistency in information exchange and decision-making activities between the different design areas.
Scheduling for just-in-time flexible manufacturing using adaptive fuzzy logic
Authors: Tedford J D , Lowe C
Published: October 2002

Production scheduling for flexible manufacturing needs to satisfy multiple and often conflicting criteria. The multicriteria problem is generally difficult to solve using existing heuristics without a means of combining rules and adapting them to changing circumstances.

A scheduling system incorporating an adaptive fuzzy logic system is proposed which can be tailored to suit the characteristics and objectives of an organization and maintain its performance by constantly adapting to changes in the production environment. The system developed indicates that its application shows benefits in terms of the resulting schedule performance and with respect to the simplicity of the scheduling algorithms required. The computational overhead of the fuzzy system is also shown to be insignificant, thus permitting real-time operation in a manufacturing situation.