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The design of plastic injection moulded part is a highly iterative process and depends largely on the human expertise including product designers, mould designers, manufacturing engineers, who need to possess thorough and broad specific knowledge and experience. The automatic recognition of features for injection moulded parts is the first prominent stage for any automatic design evaluation system. In this paper, features of plastic product are classified in three hierarchical levels of primitive features, complex features and high-level complex features. The proposed method adopts a hybrid approach, which combines the graph theoretic approach with the logic approach. Methodologies of enhanced multi-attributed adjacency graph (EMAAG) and feature-interaction feature graph (FIFG) for automatic extraction of primitive features and complex features of plastic parts, respectively, are presented. The test example shows that the methodologies developed can recognise various features of injection moulded parts successfully. [ABSTRACT FROM AUTHOR]

In the field of free form surface machining, CAM software allows one to manage various modes of tool-path generation (zig-zag, spiral, z-level, parallel plan, iso-planar, etc.) leaning on the geometry of the surface to be machined. Various machining strategies can be used for the same shape. Nevertheless the choice of a machining strategy remains an expert field. Indeed there are no precise rules to facilitate the necessary parameter choice for tool-path computation from the analysis of the numerical model of a part and the quality requirements. The objective of this paper is to provide a method to assist in the choice of the machining direction for parallel plane milling of sculptured parts. The influence of the tool-path on the final quality according to the intrinsic geometrical characteristics of the latter (curves, orientation) was studied. The directional beams are introduced and defined from the local surface parameter. Finally a methodology to optimize machining time while guaranteeing a high level of quality was developed and applied to examples . [ABSTRACT FROM AUTHOR]

The effects of an imperfect production process on the optimal production run by assuming that an elapsed time until the process shift is exponentially distributed have been studied. This problem was extended by assuming that the elapsed time until the process shift is arbitrarily distributed. The models, however, do not allow for shortages. This work has been generalized by assuming that shortages were allowed. The common assumption of all the above-mentioned models is that a fixed percentage of defective items are produced during the out-of-control period. This assumption may not be applicable in many industrial situations. Intuitively, the percentage of defective rate should increase with an increase in the duration of the out-of-control period. In fact, other research has considered an imperfect production process model with a variable rate of defective units produced when the process is in an out-of-control state. The defective rate is assumed to be a function of detection delay. The main purpose of this paper is to further generalize earlier work by introducing a time-varying percentage defective rate. This paper develops a model to determine the optimal production run for a deteriorating production system, with allowable shortages, and time-varying fraction defective rate. However, the elapsed time until the production process shift is assumed to be exponentially distributed. A unique optimal production run is found that minimizes the total expected cost. A numerical example is provided to illustrate the application of the model and to prove the convexity of the total cost function. A sensitivity analysis is also conducted to study the effects of various model parameters on the optimal production run and the total cost. [ABSTRACT FROM AUTHOR]

The function of curve offset is of importance in the process of generating a machining tool-path. The robustness of curve offset is compact with reliable invalid loops removal algorithms. The traditional method based on interference detections in searching for all contact positions is a time consuming process and prone to misunderstanding. In order to improve such removal function, a new algorithm called the forward locus tracing method (FLTM) was introduced here. The FLTM searches for all intervals split by intersections of complicated planar curves directly and transforms 2D transversal intersection problems into 1D interval identifications. This proposed mapping process in FLTM may simplify the structure of tasks and be implemented by a computer program easily for CAD systems. Some examples with multiple loops were demonstrated and the results present considerable efficiency and reliability in the offset operation. [ABSTRACT FROM AUTHOR]

A skeleton is a global shape descriptor that aims to characterize the general appearance of an object to facilitate object classification. Various ways for defining the skeleton of a polygon have been proposed in the literature. Yet, in some cases, these previously proposed skeletons may not intuitively resemble the original polygons and cannot be a good shape descriptor. This research proposes a new definition of skeletons for modeling polygons. The proposed skeleton is termed the area-trimmed (A-trimmed) skeleton. In modeling the global shape of polygons, the A-trimmed skeleton performs much better than other skeletons proposed in the literature. The A-trimmed skeleton can be applied in group technology and facilitate tasks such as punched-part design and fixture design. [ABSTRACT FROM AUTHOR]

Higher degree curves are used in applications because they are easier to manipulate interactively but require heavy computation. Most of the equations for curves used popularly in CAD software are of degree 2 and 3, because two curves of degree 3 can guarantee 2nd derivative continuity at the connection point. This study proposes a different but simpler method than any put forward before to deal with degree reduction of free-form curves. The reduced curves use the simplest knot vector type, i.e., the open uniform knot vector. Unlike other methods, this study does not modify or refine the knot vectors but perturb the control points globally. After obtaining an initial condition, a radiating web-like search algorithm is applied to detect the optimum positions. These NURBS curve formats reach basic industrial standards for CAD/CAM/CNC applications. By defining a global bound error function, this algorithm can achieve an optimum solution not only for NURBS curves but also Bézier/B-spline curves. [ABSTRACT FROM AUTHOR]

Process incapability index has been introduced to provide quantitative measures on process performance. Contributions of the estimated incapability index based on sub-samples have been proposed under the normality assumption. In this paper, investigations based on sub-samples are considered under general conditions having fourth central moment. The limiting distribution of the estimated incapability index based on sub-samples is derived. An approximate 100(1-α)% upper confidence bound of the considered incapability index is constructed. A demonstrated example is also provided to illustrate how the proposed approximate upper confidence bound may be applied for judging whether the process runs under the desirable quality requirement. [ABSTRACT FROM AUTHOR]

Based on multi-point forming (MPF) technology, a novel digital manufacturing method of cranial titanium plates for the repair of skull defects is developed in this paper. First, a 3D triangular mesh model of the skull is constructed from a CT data set. Then, a non-uniform rational B-splines-format (NURBS-format) patch surface is obtained by surface interpolation based on the skull polygon model. Finally, the patch surface model is input to MPF CAD/CAM software and the cranial titanium prosthesis is deformed by an MPF press. The method has many new features compared with other means. Implementing medical image processing and MPF technology, the method can remarkably shorten the production cycle of titanium cranioplasty, as well as offer improved fitting precision. About 20 practical applications have been finished, which prove the feasibility and efficiency of the method. [ABSTRACT FROM AUTHOR]

This paper presents a genetic algorithm-based approach for automatic functional design of mechanical systems. The proposed method automatically finds a set of optimal or near-optimal design solutions with respect to desired functional requirements stored in a pre-built device database. Although, typically, the design solution space of a given mechanical system is very large, the proposed strategy can generate high-quality design solutions in a timely manner. The method considers life cycle cost (LCC) factors as one of the design optimization criteria, since LCC factors have an important impact on product competency in the current market. Fuzzy logic is used to transform linguistic design requirements into numerical values. A case study is presented to illustrate the operation of the genetic algorithm-based functional design method and the efficiency of the method for optimizing the final design. [ABSTRACT FROM AUTHOR]

Test wafers are used to measure the process quality in semiconductor manufacturing. Test wafers are reusable by recycle cleaning and can be downgraded to the downstream processes. Most previous studies on test wafers aimed to reduce the use of test wafers by making appropriate operational decisions. Yet, the effective improvement of yield in the recycle process of test wafers is seldom explored. This paper formulates a decision problem and proposes two solution methods for selecting the yield improvement alternatives in the test wafer recycle processes. The decision problem is to determine the yield improvement target for each recycle process in order to minimize the use of test wafers, under a given budget for yield improvement. The two solution methods involve a genetic algorithm and a marginal allocation algorithm. The two methods yield very close solutions, but the marginal allocation method is better because it requires less computation time. [ABSTRACT FROM AUTHOR]

This paper presents an economic discrete replacement model for a single-unit system subjected to external shocks. In this model, the system is affected by both external shocks and its ageing process. The external shocks are divided into two types, namely non-lethal and lethal, depending on their effect to the system. A non-lethal shock damages the system by increasing the failure rate of a certain degree, while a lethal shock causes the system into instantaneous failure. The failure rate also increases with the system’s ageing process. The system is replaced at the instant of the nth non-lethal shock, or on failure, whichever occurs first. The research proposed a model where the long run expected cost per unit time is formulated by introducing relative costs and derived as a criterion of optimality. By minimizing the cost, an optimal number, n*, is then found. The optimal number, n*, is also verified to be finite and unique under certain conditions . [ABSTRACT FROM AUTHOR]

The electronic industry is rapidly developing, creating high demand for IC production. Etched semiconductor lead frames are the basic material used in IC packaging. IC packaging requires high-precision lead frames. The dimensions of the pilot hole are generally required to be highly precise in lead frame manufacturing. The photo-etching process must control the dimension of the pilot hole and record the manufacturing data of the etching machine and inspection data. This study presents the development of an artificial neural network (ANN) model that can be applied to construct the predicting model. The predictive model can estimate the dimensions of the pilot hole and thus determine the process parameters needed to improve lead frame quality in the etching process. [ABSTRACT FROM AUTHOR]

Process capability analysis ( PCA) is frequently employed to evaluate a product or a process if it can meet the customer’s requirement. In general, process capability analysis can be represented by using the process capability index ( PCI). Until now, the PCI was frequently used for processes with quantitative characteristics. However, for process quality with the qualitative characteristic, the data’s type and single specification caused limitations of using the PCI. When the product can not meet the target, even if it lies in the specified range, it should lead to the corresponding quality loss. Taguchi developed a quadratic quality loss function ( QLF) to address such issues. In this study, we intend to construct a measurable index which incorporates the PCI philosophy and QLF concept to analyze the process capability with the consideration of the qualitative response data. The manufacturers can not only employ the proposed index to self-assess the process capability, but they also can make comparisons with the other competitors . [ABSTRACT FROM AUTHOR]

This paper presents the design, development, and implementation of an integrated control framework that provides a real-time supervisory control model with limited look-ahead capability for flexible manufacturing systems. Control goals and policies are modeled and characterized by a fuzzy rule base, which is integrated with the control model. The framework consists of a finite state machine generator and a controller. The generator model is equipped with an output function and output sets. The controller model has a four-stage decision-making structure. The controller monitors performance measures of the manufacturing system and reacts according to the changes in the system states in order to keep the performance measures at desired levels. The integrated framework has been implemented on a software platform in order to validate its effectiveness. The performance of the framework has been tested on a hypothetical flexible manufacturing system using a simulation . [ABSTRACT FROM AUTHOR]

Assembly line balancing (ALB) aims at distributing those work required to assemble a product in mass or series production among a set of workstations in an assembly line. Heuristics approaches, in corporation with computer simulation, have demonstrated a number of advantages in practice. Recognizing the importance of interactions between production planners and the scheduling system, this paper discusses the design and implementation of a Web-based ALB advisor for scheduling hard disk drive assembly involving multiple criteria. With the assistance of such an ALB advisor, production engineers, who may have difficulties in understanding those sophisticated ALB heuristics, can remotely present and specify their particular ALB problems. Based on the user input, the advisor will compose a schedule based on various heuristic algorithms embedded in its library. The schedule can be manipulated directly via a graphical user interface. The advisor also generates simulation models for the user-specified ALB problems and presents the user with performance evaluation of the suggested ALB solutions. [ABSTRACT FROM AUTHOR]

In this paper, we propose a flow path to evaluate the process capability of an entire product composed of multiple process characteristics. There are six steps in the flow path. Whether process data comply with a normal distribution or a non-normal distribution, the flow path can be applied. Based on Cpu, Cpl, and Cpn, the research aims to develop a multi-process capability analysis chart (MPCAC) model to evaluate process capability in a normal distribution. Similarly, the research aims to define non-normal multi-process capability analysis chart (NMPCAC) to evaluate process capability in a non-normal distribution based on Npu, Npl, and Npn. [ABSTRACT FROM AUTHOR]

In this paper, we introduce the manufacturing message specification (MMS) and compare two distributed object approaches–distributed component object model (DCOM) and common object request broker architecture (CORBA), suggest characteristics that DCOM is more suitable for automated manufacturing system (AMS) control software integration. In order to make a control system provided with interoperability and reconfigurability etc., a hybrid control system is built for AMS, then a control software architecture is presented for AMS based on distributed object DCOM middleware and MMS standard. The object-oriented DCOM communication protocol is used to implement the MMS in a distributed object mode. DCOM and MMS combination brings the operating system independent communication capabilities to manufacturing devices such as CNC machine tools and industrial robots in AMS. Control software implementation of MMS concepts in the DCOM environment is particularly discussed. Finally, to verify the control software architecture for AMS, prototype development has been implemented in VC++ 6.0 developer environments. [ABSTRACT FROM AUTHOR]

Reviewed were the mathematical methods that are used to investigate the polling systems which found wide application in modeling and design of various transport and industrial processes. Emphasis was made on the models of polling systems used to investigate the wireless broadband networks. The polling systems were classified; presented were stochastic models and methods of investigating discrete-time and continuous-time systems, systems with cyclic, periodic, and random queue polling, as well as the methods of their optimization. [ABSTRACT FROM AUTHOR]

This paper surveys the literature in the holonic manufacturing systems area in an attempt to bring together the key issues in the development and applications of holonic systems. A brief introduction presents the characteristics of today’s manufacturing environment and the requirements for next generation manufacturing systems. Then, starting with considerations about the origins of the holonic concept and its first applications in manufacturing, the paper presents the advances made in applying the holonic concept to manufacturing systems area. Several considerations for the development of holonic manufacturing systems and specific holonic system requirements are discussed. As holonic concept is considered a solution for next generation manufacturing systems, there is a significant number of applications and implementations of the holonic concept in manufacturing systems domain. The most important and relevant approaches developed so far are presented. Finally, a short conclusion and future research directions in the area are provided [ABSTRACT FROM AUTHOR]

The semiconductor manufacturing system has become one of the most important manufacturing systems in recent years. Intrabay automation for wafer transport is in high demand in a 300 mm foundry fab. The control of the transport system plays an important roles in manufacturing efficiency and the satisfaction of production strategy. In general, efficiency is the most important issue that has appeared in most research of automated transport systems. However, how to dynamically adjust the transport policy to meet the production strategy and to increase the transport efficiency as well seems to be more crucial to modern semiconductor manufacturing systems. In this paper, a fuzzy-logic-based multimission-oriented overhead vehicle dispatcher is developed. The vehicle dispatching rule is assigned in real-time according to the statistics of the manufacturing performance. In this manner, the dispatching rules can be adjusted according to possible high-risk lots so that most of the production strategies can be satisfied. If all of the lots meet the prescribed production strategies, then the nearest-job-first rule can be used to offer higher transport efficiency. In addition, the proposed vehicle dispatcher is also capable of deadlock-free operation, collision avoidance, and blockage prevention. Finally, this paper uses AutoMod simulation software to construct and evaluate the manufacturing models. By evaluating the simulation results, the proposed intelligent multimission-oriented vehicle dispatcher performs better performance than the others, and all of the production strategies are satisfied . [ABSTRACT FROM AUTHOR]

Manufacturing organizations worldwide are re-inventing their product development practices in an effort to satisfy changing customer requirements. In the context of these changes influencing the manufacturing community, there is a need to develop frameworks, architectures, and methods to facilitate the creation, implementation, and functioning of virtual enterprises (VEs). This paper presents an Internet-based framework, which supports distributed process planning activities in the context of a VE. Typically, in a VE, the enterprise partners are distributed, and possess diverse skills and heterogeneous software resources, which employ heterogeneous computing platforms. Using the developed approach, physically distributed product development partners can collaborate virtually via the Internet and integrate their life-cycle product development activities through seamless information exchange. In this framework, the distributed manufacturing resources communicate with each other via the Internet inter-ORB protocol (IIOP) using an object request broker (ORB) at each distributed site. [ABSTRACT FROM AUTHOR]

This study used statistical control charts as an efficient tool for improving and monitoring the quality of manufacturing processes. Under the normality assumption, when a process variable is within control limits, the process is treated as being in-control. Sometimes, the process acts as an in-control process for short periods; however, once the data show that the production process is out-of-control, a lot of defective products will have already been produced, especially when the process exhibits an apparent normal trend behavior or if the change is only slight. In this paper, we explore the application of grey forecasting models for predicting and monitoring production processes. The performance of control charts based on grey predictors for detecting process changes is investigated. The average run length (ARL) is used to measure the effectiveness when a mean shift exists. When a mean shift occurs, the grey predictors are found to be superior to the sample mean, especially if the number of subgroups used to compute the grey predictors is small. The grey predictor is also found to be very sensitive to the number of subgroups. [ABSTRACT FROM AUTHOR]

Topology optimization is used in the initial stage of the product manufacturing process. However, the non-manufacturable or non-machineable results of topology optimization have become an obstacle to process manufacturing. This paper proposes a modified topology optimization method by adding manufacturing and machining constraints to the topology optimization formulation. A hybrid topology optimization algorithm (combining the method of moving asymptotes and wavelets) is applied to solve this optimization problem. With this approach, the design space can be reduced and an engineering-accepted and manufacturable topology result can be guaranteed. [ABSTRACT FROM AUTHOR]

The requirements for faster product development cycles, lower product cost and environmental sustainability are ever increasing in today’s globally competitive market. Tooling is a very important phase in the product manufacturing cycle. To overcome the shortcomings of long lead-time and high cost associated with conventional tooling processes, new tooling methods with shorter lead-time and lower cost are strongly under demand. In this study, the feasibility of the proposed new rapid tooling process based on back support of a metal shell with packed metal powders is examined. First, the effect of metal powder properties, such as powder shape, size, and size distributions, on powder-packing behaviour is investigated experimentally. Then, the compressive behaviours of the metal shell and the shell-powder assembly are analysed numerically with different compressive loading. The study indicates that the proposed new rapid tooling method can potentially be used for injection moulding applications. [ABSTRACT FROM AUTHOR]

Fixed and orbiting scrolls of scroll compressor components have spiral grooves known as scroll wraps. High-precision contour milling using end mills is the best method to produce these scrolls. The aim of our present work is to recognize the mechanism of tool wear on end mills in bottom face machining and to reduce tool wear in highly efficient milling. This paper describes an effective coolant supply system to the cutting point and an appropriate tool geometry developed in the study. The following conclusions can be drawn: (1) By supplying coolant to the cutting edge through the center hole of the tool at a cutting speed of 230 m/min, the wear rate of the flank wear can be reduced to approximately 1/50 of the wear observed in conventional coolant supply. (2) The optimal back clearance angle is 5° for abrasive resistance in the turning operation. (3) By applying 5° to the back clearance angle, the wear rate of the corner edge can be reduced to 1/6 of that observed when the back clearance angle was 15°. [ABSTRACT FROM AUTHOR]

The research of Dickson [1] and Weber et al. [2] about the performance evaluation of suppliers pointed out that quality and delivery are two important assessable items. Chen and Yung [3] indicated that the significance of delivery would only increase in the future. Obviously, customers value quality and delivery. Therefore, a superior quality of product and rapid manufacturing process are the major factors in obtaining orders. Much research has been carried out on quality assurance, but the research on delivery is rare. Thus, this paper uses the manufacturing process of optical glass as an example to propose a performance index for a manufacturing time schedule and related a suite of objective evaluation models used. This evaluation method is very convenient and efficient for management to monitor the multi-manufacturing performance of each stage of a manufacturing process for deliveries of high quality. [ABSTRACT FROM AUTHOR]

Production decisions in real dynamic flexible manufacturing systems (FMS), especially in the early stages are often made with limited information. Information is limited because scheduling knowledge is hard to establish in such an environment. Though the machine learning technique in the field of Artificial Intelligence is thus used for this task by many researchers, this research is aimed at increasing the accuracy of machine learning for FMS scheduling using small data sets. Approaches used include data-fuzzifying, domain range expansion, and the application of adaptive-network-based fuzzy inference systems (ANFIS). The results indicate that learning accuracy under this strategy is significantly better than that of a traditional crisp data neural networks. [ABSTRACT FROM AUTHOR]

Many manufactured items receive surface coatings for decoration and/or protection against damage. In a number of places along the production line emissions of (VOC) Volatile Organic Compounds can occur. Because VOC are a major contributor to photochemical smog, control of VOC emissions is a major concern for the industries' commitment to the environment. Approaches for process optimisation have a long tradition within chemical and process engineering for the systematic identification of cost- and resource-efficient production options. The challenge in the context of supply chain management is the optimal recovery and reuse of materials not only for single substances or energy flows in large chemical installations, but also for smaller production processes and various mass and energy flows within and between enterprises. Based on a case study from the industrial coating of bicycle frames, an approach for Multi Objective Pinch Analysis (MOPA) for the evaluation of overall recovery potentials for energy, water and VOC is presented. Moreover, a metric for resource efficiency is introduced as a measure for the possible savings potential and for the savings ultimately realised. This integrated approach requires a tight coupling of mass, energy, economic and environmental assessment methods and demands a highly interdisciplinary approach. [ABSTRACT FROM AUTHOR]

In this paper we propose an extended object-oriented Petri nets (EOPNs) for effective modeling of large-scale complex re-entrant manufacturing systems (ReMSs). To cope with their complexity because of the re-entrant process route and the mixed production mode, a special type of transition called a main-bus gate (MBG) is introduced, which can cause products to undergo every re-entrant manufacturing stage. A hierarchical approach is also applied to cope with the complexity. As a typical large-scale complex ReMS, the semiconductor wafer fabrication system (SWFS) is taken as an example for demonstrating the proposed EOPNs. A case study is provided to show the modelling procedures, and the resulting model validates that the EOPNs can cope well with the modelling complexity of large-scale complex ReMSs. [ABSTRACT FROM AUTHOR]

One of the most critical issues encountered in the area of quality engineering is the selection of an appropriate quality loss function to relate key quality characteristics of a product to its quality performance. The loss function can be used to evaluate the quality loss in terms of monetary units that enables managers to quantify unobservable costs. It aids manufacturers to evaluate quality improvement projects more rigorously, hence, the choice of paths for quality enrichment depends on the type of loss function. Although several multivariate quality loss functions have been proposed, these models only considered the-nominal-the-best (N-type) quality characteristics. The effect of other types of quality characteristics was not addressed. In this paper, a cost model is proposed to evaluate the quality level of a product with multiple the-larger-the-better (L-type) quality characteristics. An example with two quality characteristics is given to illustrate the application. [ABSTRACT FROM AUTHOR]

Process planning is a function in a manufacturing organization that selects the manufacturing processes and parameters to be used to transform a part from its initial state to the final form according to the design specifications. It is a bridge between product design and product manufacturing. The activities of process planning include understanding the part specifications or product design data, selection of job material and tool, setup planning, sequencing the operations within a setup, determination of process parameters for each operation, and generation of process sheets. This paper outlines a method to develop a generative computer-aided process planning system for axisymmetric components for a job shop environment. A decision support system is used to perform semi-structured tasks such as setup planning and establishing precedence relationship among various operations. [ABSTRACT FROM AUTHOR]

Because there is no criterion available, discretization of numerous data about objects of information systems may be the biggest obstacle to performing inductive learning from instances. Based on a Singular value decomposition of matrix and Fuzzy C-means clustering, a discrete approach of continuous attribute values in a decision table, with continuous condition attribute values and discrete decision attribute values, has been proposed. Rough sets theory has been employed for diagnostic rule acquisition of rotating machinery with consideration of conflicting objects of decision table. A weak matching mode of objects with diagnostic rules has been proposed, with diagnostic conclusion and its belief degree obtained by comparing new objects with the standard diagnostic rules. An example at the end of this paper shows that the acquired rules have good merits of the ability of generalization and extension, and to some extent, improves classification level. [ABSTRACT FROM AUTHOR]

Stochastic flow shop scheduling is a typical and widely studied NP-hard stochastic optimisation problem with strong industrial roots. However, due to inaccurate estimation of objective values, NP-hardness and a limited computing budget, it is generally hard to solve such stochastic optimisation problems effectively and efficiently. Based on the idea of order comparison and goal softening, ordinal optimisation (OO) has been widely applied for stochastic optimisation. In this paper, OO and optimal computing budget allocation (OCBA) as well as a genetic algorithm (GA) are reasonably hybridised to propose an effective genetic ordinal optimisation (GOO) approach for flow shop scheduling with stochastic processing times. In GOO, limited computing effort can be intelligently allocated by OCBA to provide reliable and robust evaluation and identification of good solutions in a population, and the solution space can be well explored by an order-based evolutionary genetic search with the good solutions identified by OCBA. Simulation results based on benchmarks demonstrate the effectiveness of the GOO by comparison with traditional methods. Moreover, the effects of some parameters on the optimisation performance are discussed. [ABSTRACT FROM AUTHOR]

An integration strategy for assembly sequence planning and sequence scheme evaluation is proposed. This strategy can be used to plan a reasonable assembly sequence, to optimize a sequence scheme, and to predict whether a collision will occur between the assembly tool and assembled components by considering factors like target components and assembly resources. A hybrid method is presented for assembly sequence modeling that combines human-computer interactive operations to manually build a hierarchical assembly sequence main model and a hybrid graph method to automatically generate sub-assembly sequence schemes of the main model. An optimization algorithm based on time-cost is introduced to handle a best candidate components selection. This relieves the problem of limited capability found when handling large size assembly models with traditional methods. The essential issues involved in system implementation are discussed as well; these include a representation method for the assembly consequence model, an optimization model of assembly sequence planning, and an object-oriented system architecture model employed with multi-agent technology for visually evaluating the assembling process. This system, KM computer-aided assembly process planning, KMCAAPP, has been developed on the basis of our previous work, KMCAD3; KMCAAPP uses the presented approach. KMCAAPP can be integrated with CAD model from KMCAD3D. A case study shows that the presented approach can use large CAD assembly models and delivers a feasible and effective way to integrate the assembly sequence planning process with scheme evaluation by visually evaluating the assembling process. This allows the identification of design errors in a timely manner and mitigates economic loss. [ABSTRACT FROM AUTHOR]

In apparel manufacturing, experience and subjective assessment of production planners are used quite often to plan the production schedules in their fabric-cutting departments. The quantities of cut-pieces produced by fabric-cutting departments based on these non-systematic schedules cannot fulfil the cut-piece requirements of the downstream sewing lines and minimize the makespan. This paper proposes a genetic algorithms (GAs) approach to optimize both the cut-piece requirements and the makespan of the conventional fabric-cutting departments using manual spreading and cutting methods. An optimization model for the manual fabric cutting process based on GAs was developed. Two sets of production data were collected to validate the performance of the model and the experimental results were obtained. From the results, it can be found that both the makespan and cut-piece fulfilment rates are improved in which the latter is improved significantly. [ABSTRACT FROM AUTHOR]

Problems that arise during strengthening of the beds of existing structures under the soil conditions prevalent in Moscow are discussed. Results are cited for experimental and production studies on the strengthening of soils by jet technology under an existing slab foundation. [ABSTRACT FROM AUTHOR]

The authors present a set of new measures for comparing optimization algorithms in dynamic environments. The authors introduce a new decomposition based multi-objective genetic algorithm with adaptive multi-population strategy to address multi-objective permutation flowshop scheduling problems. The authors describe a self-adaptive fruit fly optimization algorithm for solving high-dimensional global optimization problems. [Extracted from the article]

In this paper, two process and die design methods for ball valve forming from stainless steel tubes are compared: one is the tube hydroforming method (THFM), and the other is the tube nosing method (TNSM). Simulations on hydraulic expansion, axial feeding, and tube nosing of the ball shell forming with the two methods using the program DEFORM-3D are carried out. The influence of the two methods on workpiece formability and wall thickness distribution of ball valve forming is examined. A tube nosing experiment is carried out with a SUS304 stainless steel tube at room temperature. An accepted product of ball valve satisfying the industrial demand is obtained using TNSM. [ABSTRACT FROM AUTHOR]

Collaborative and distributed engineering Web services are emerging as a viable alternative to the traditional design and engineering process automation. Existing approaches have limitations in supporting long-running engineering transactions, automatic engineering process orchestration and choreography, synchronous and asynchronous conversation, and geometric abstraction for transmission and sharing. In this paper, we present a process-centric engineering Web services framework to overcome these limitations by utilizing BPEL-based (business process execution language) process templates and coordination broker-based conversation support. This paper also discusses the synchronization of engineering Web services, which can be either peer-centric or process-centric to support long-running engineering transactions and conversation. The process orchestration and choreography broker works as a service dispatching and aggregation agent for executing process templates, which enables the individual activity of the engineering process to dynamically invoke one of the alternative Web services through the run-time process brokering. Further, the paper presents how to support collaboration over the running process using conversation policy . [ABSTRACT FROM AUTHOR]

Defects in automotive aluminum alloy casting continue to challenge metallurgists and production engineers as greater emphasis is placed on product quality and production cost. A range of casting-related defects found in low-pressure die-cast aluminum wheels were examined metallographically in samples taken from several industrial wheel-casting facilities. The defects examined include macro- and micro- porosity, entrained oxide films, and exogenous oxide inclusions. Particular emphasis is placed on the impact of these defects with respect to the three main casting-related criteria by which automotive wheel quality are judged: wheel cosmetics, air-tightness, and wheel mechanical performance. [ABSTRACT FROM AUTHOR]

A synthetic control chart for monitoring the changes in the standard deviation of a normally distributed process is proposed in this paper. The synthetic chart consists of the sample range (R) chart and the conforming run-length ( CRL) chart. The R chart can be viewed as a special case of the synthetic chart. The operation, design and performance of this chart are described. Average run- length comparisons between other procedures and the synthetic chart are presented. It indicates that the synthetic chart is a good alternative for monitoring process dispersion. The variable sampling interval (VSI) schemes, as an enhancement to the synthetic chart, are discussed to further improve the chart performance. An example is presented to illustrate the application of synthetic chart and its VSI scheme. [ABSTRACT FROM AUTHOR]

This is not an overview paper. This paper is concerned with simply making an expository note on three issues that should be taken into account when making an economic justification of investments in advanced manufacturing systems. They are the product of cost information, uncertainty, and intangible benefits available from the investment, which have been widely discussed in isolation for the last 20 years. The main purpose of this paper is primarily to provide practitioners with a synopsis of leading edge research in the area of justifying investment in advanced manufacturing systems and to stimulate a desire for better understanding and application of knowledge and techniques that will enhance professional practice. Once companies replace their existing manufacturing systems with advanced manufacturing systems, the characteristics of the manufacturing environment are greatly changed in general. Such different characteristics usually entail three problems in justifying investment in the advanced manufacturing systems: (1) Calculating an accurate product cost, (2) Dealing with uncertainty inherent therein and (3) Intangible benefits available from the investment project. Each of these problems has been greatly discussed, mostly independently, in the academic world for the last two decades. In this paper we will revisit and discuss each of them on a general, but relatively informal, level using simple examples to illustrate the main points. The paper is intended to be expository and aimed primarily to hopefully provide practitioners with a synopsis of leading edge research in the area of justifying investment in advanced manufacturing systems and to stimulate a desire for better understanding and application of knowledge and techniques that will enhance professional practice. [ABSTRACT FROM AUTHOR]

In today’s competitive market, manufacturers need to quickly adapt to the changing demands of the customers. Reconfigurable manufacturing system (RMS) is a cost-effective system that can easily absorb frequent changes in product demands. In this article such a system is modelled using expert enhanced coloured fuzzy Petri net (EECFPN), which considers the demands of customers as a fuzzy parameter and vividly captures the reconfigurability aspect of RMS. A fuzzy control strategy (FCS) is proposed to deal with the information delays occurring during information transfer or decision implementation. After intensive computational experimentation, it has been found that FCS outperforms the alternative priority (AP) heuristic and it is considered an effective measure to deal with situations where considerable information delay is involved. [ABSTRACT FROM AUTHOR]

Statistical techniques are effective and powerful means of quantifying the variability of processes, analyzing this variability with reference to product requirements, and eliminating this variability in product manufacturing. Many process capability indices have been effectively and widely used to determine whether the quality of a process meets preset targets. However, conventional process capability indices cannot be applied to assess the entire process capability of a product family with nominal-the-best specifications. This work presents a novel process capability index ( C), which takes into account all family members. The index C pp is a simple transformation from index C pm, and C provides additional, individual information concerning the accuracy and precision of a process. Vännman’s (δ, γ)-plot [Vännman and Deleryd, Quality and Reliability Engineering International 15(3): 213–217 (1999)] is revised to compare the process capabilities of family members under both 100% inspection and sampling plans. Examples are provided to demonstrate the method’s practical application. [ABSTRACT FROM AUTHOR]

This paper proposes a general formulation of a nonparametric frontier model introducing external environmental factors that might influence the production process but are neither inputs nor outputs under the control of the producer. A representation is proposed in terms of a probabilistic model which defines the data generating process. Our approach extends the basic ideas from Cazals et al. (2002) to the full multivariate case. We introduce the concepts of conditional efficiency measure and of conditional efficiency measure of order- m. Afterwards we suggest a practical way for computing the nonparametric estimators. Finally, a simple methodology to investigate the influence of these external factors on the production process is proposed. Numerical illustrations through some simulated examples and through a real data set on Mutual Funds show the usefulness of the approach. [ABSTRACT FROM AUTHOR]

A procedure for the automatic generation of the robot programming used in manufacturing operations is introduced in the present paper. The off-line programming system developed here includes graphical simulation of the robot and its workcell, kinematic model of the robot, motion planning and creation of the NC code for manufacturing process. The proposed system is applied in a robot with five revolute joints for manufacturing operations and in a robot with six revolute joints for welding operations. [ABSTRACT FROM AUTHOR]

Electrodischarge diamond grinding (EDDG) is a hybrid machining process comprising conventional grinding and electrodischarge machining (EDM) as its constituent processes. It has the potential of shaping advanced engineering materials. Temperature of the workpiece and material removal rate are chosen as responses in full factorial (33) design with current, pulse-on time, and wheel speed as process parameters. Specific energy is a vital consideration for any machining process. EDM is known for its inefficiency. Experiments were conducted with a specially fabricated bronze disk as tool electrode to evaluate specific energy in EDM, and the results were compared with that of EDDG. It has been found that specific energy required in EDDG is less than that in EDM with a rotating disk electrode. [ABSTRACT FROM AUTHOR]

In electronics manufacturing the time-pressure dispensing system has been widely used to squeeze adhesive fluid in a syringe onto boards or substrates with pressurised air. For accurate control of the fluid volume, it is vital to have a thorough understanding of the whole process. However, the complexity of the process, which includes air-fluid coupling and their nonlinear uncertainties, makes it difficult to obtain an accurate process model. Using the spectral method, an approximate fluid flow model for both the Newtonian and non-Newtonian fluid can be developed. By taking into account nonlinear flow passing through the valve, attenuation and time delay in the pneumatic lines, syringe chamber dynamics and fluid flow dynamics, a simple but effective model is derived to describe the whole dispensing system with reasonable accuracy. Experiments performed thereafter validate the model. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new joint-based assembly modeling method. In joint-based assembly modeling, the assembly constraints are specified on the components, but not on the geometric elements of the components. The proposed method generates assembly models from kinematic joint constraints by applying three procedures (1) to extract all feasible JMFs (Joint Mating Feature) for each mating component using information on joint constraints, (2) to derive mating alternatives for each pair of mating components after reducing the number of JMFs using the pruning criteria, and (3) to generate an assembly model by choosing the intended one from the mating alternatives for each pair of mating components and solving the JMF constraints. Since the joint constraints are expressed in terms of the relations between components rather than relations between geometric elements, the proposed method is more intuitive and natural for assembly modeling and supports modeling activities effectively by minimizing user interactions. By using joint mating constraints for assembly modeling, moreover, the kinematic behaviors of assemblies determined in the conceptual design stage can be directly applied and consistently maintained up to the detailed design stage. In the proposed method, it is also not necessary to re-input the mating constraints even when the component topology is changed. [ABSTRACT FROM AUTHOR]

Proposed in this paper is a new approach for offset surface construction using three- dimensional (3D) distance volumes. After converting an original compound surface into a triangular mesh, the approach creates a distance volume of the triangular mesh. With this distance volume and a given offset value, it extracts the offset points in each slice to create a sequence of two dimensional (2D) cross-sections. The approach then performs offset surface construction using the serial cross-sections. For more accurate and efficient computation of the distance volume, the concept of space division is combined with the concept one of distance propagation to the whole space of interest. The resulting offset surface is a G1 composite surface consisting of three kinds of surfaces: skinned, capped, andor branched surfaces. The proposed approach provides offset surfaces that are accurate and free of degeneracy. Some experimental results demonstrate its usefulness and quality. [ABSTRACT FROM AUTHOR]