Showing papers in "International Journal of Production Research in 2002"
TL;DR: In this paper, the authors present a survey of the AGV scheduling and routing problems in automated materials handling systems, flexible manufacturing systems and even container handling applications and differentiate it from seve...
Abstract: Automated guided vehicles (AGVs) are now becoming popular in automated materials handling systems, flexible manufacturing systems and even container handling applications. In the past few decades, much research has been devoted to the technology of AGV systems and rapid progress has been witnessed. As one of the enabling technologies, scheduling and routing of AGVs have attracted considerable attention. Many algorithms for the scheduling and routing of AGVs have been proposed. However, most of the existing results are applicable to systems with a small number of AGVs, offering a low degree of concurrency. With a drastically increased number of AGVs in recent applications (e.g. in the order of a hundred in a container handling system), efficient algorithms are needed to resolve the increased contention of resources (e.g. path, loading and unloading buffers) among AGVs. This survey paper first gives an account of the emergence of the problem of AGV scheduling and routing. It then differentiates it from seve...
381 citations
TL;DR: In this paper, the scope, definitions and strategies of agile manufacturing have been examined and a framework has been presented as a basis for understanding the major strategies and relevant technologies of AM.
Abstract: Agile Manufacturing (AM) is a relatively new operations concept that is intended to improve the competitiveness of firms. Manufacturing/service processes based on AM are characterized by customer-supplier integrated processes for product design, manufacturing, marketing, and support services. Agile manufacturing requires enriching of the customer; cooperating with competitors; organizing to manage change, uncertainty and complexity; and leveraging people and information. In recent years, a number of research papers have been published in the area of AM. The term 'agile' was coined in 1991. However, there are still some serious concerns that prevent companies from taking an entirely different direction from AM. Considering the potential importance of agile manufacturing in 21st century manufacturing competitiveness, an attempt has been made in this paper to reexamine the scope, definitions and strategies of AM. In addition, a framework has been presented as a basis for understanding the major strategies and relevant technologies of AM.
320 citations
TL;DR: A comprehensive state-of-the-art review on various tolerancing issues in design and manufacturing can be found in this article, with a view toward a balanced understanding of the various problems in tolerancing by presenting some typical research work for each of the classified fields.
Abstract: Ever since the plus/minus limits on dimensions first started to appear on engineering drawings in the early 1900s, tolerances have been one of the most important issues for every engineer involved in the product realization processes. In particular, with the advancement of computers and CAD/CAM techniques in the 1970s, the tolerance-related issues have continuously drawn the attention of many researchers since then. As a result, a tremendous number of research articles have been published over the last 30 years. This paper aims at a comprehensive state-of-the-art review on various tolerancing issues in design and manufacturing. However, due to the overwhelming number of existing research publications, any reviews on tolerancing issues could by no means be exhaustive. Rather, this review attempts to provide the reader with a view toward a balanced understanding of the various problems in tolerancing by presenting some typical research work for each of the classified fields, and tries to draw the potential ...
296 citations
TL;DR: In this article, the authors highlight some major weaknesses of the extant literature with respect to the conceptualization, operationalization, and modelling of SCM, identify potential causes underlying these shortcomings, and give some recommendations to improve theory development in this area.
Abstract: Despite the growing interest in supply chain management (SCM), our understanding of the subject issue is still limited, largely due to inadequate attention being placed to theory building. To address this problem, this paper highlights some major weaknesses of the extant literature with respect to the conceptualization, operationalization, and modelling of SCM, identifies potential causes underlying these shortcomings, and gives some recommendations to improve theory development in this area. Specifically, it demonstrates that (1) the SCM construct has been perceived narrowly from the perspective of a particular traditional function of a firm; (2) the construct validity is threatened due to inadequate pre-operational explication of the content domain, among other operationalization problems; and (3) the dominant conceptual SCM models focus mainly on the practices-performance relationship, overlooking the context-practices relationship. A greater advance in theory development is possible if researchers ado...
290 citations
TL;DR: In this article, the authors apply competence and capability theory to value chain flexibility and explore the relationships among environmental uncertainty, value-chain flexibility and competitive advantage, and provide a framework for understanding these relationships and build a theoretical foundation for developing and testing relationships among these constructs.
Abstract: Increasing global competition, accelerating technological change and expanding customer expectations are creating a turbulent environment. Flexibility is a mechanism that enables firms to cope with this increasing uncertainty because it facilitates a quick response, which is strategically important as an order-winning criterion. To meet customer needs, flexibility must be across the value chain and it should include product development, manufacturing, logistics and spanning activities. The paper applies competence and capability theory to value chain flexibility and it explores the relationships among environmental uncertainty, value chain flexibility and competitive advantage. It provides a framework for understanding these relationships and builds a theoretical foundation for developing and testing relationships among these constructs. The research should help managers identify the flexible capabilities that impact relationships with their customers and the flexible competences that support these capabi...
254 citations
TL;DR: This paper considers a well-established production and distribution scheduling algorithm, called the Automatic Pipeline, Inventory and Order Based Production Control System (APIOBPCS) within a Vendor Managed Inventory (VMI) supply chain and develops a transfer function model of the system using causal loop diagrams, block diagrams, difference equations and z -transforms.
Abstract: This paper considers a well-established production and distribution scheduling algorithm, called the Automatic Pipeline, Inventory and Order Based Production Control System (APIOBPCS) within a Vendor Managed Inventory (VMI) supply chain. It develops a transfer function model of the system using causal loop diagrams, block diagrams, difference equations and z -transforms. Important insights into the VMI supply chain are derived from the mathematical model pertaining to the stability and robustness of the VMI system. Analysis confirmed by dynamic simulation clearly demonstrates instability arising from poor design. We also demonstrate its avoidance via our recommended parameter settings for tuning the two feedback loops within the supply chain for a specific production delay. The procedure is readily extended for other production delays and distributions.
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243 citations
TL;DR: In this paper, the authors discuss the importance of a disassembly line in product recovery and demonstrate how some important factors in disassembly can be accommodated to balance a paced disassemb line by modifying the existing concept of assembly line balancing.
Abstract: There are several situations in a product recovery environment where products may be disassembled for economical and regulatory reasons. The disassembly line is perhaps the most suitable setting for disassembly of large products (consisting of numerous components) as well as small products received in large quantities. This paper discusses the importance of a disassembly line in product recovery. The objective of the disassembly line is to utilize the available resources as efficiently as possible while meeting the demand for recovered parts. However, there are many complicating matters that need to be considered to create an efficient disassembly line. Our primary goal is to discuss these issues and provide a better understanding of the complications and their effects on the disassembly line. We also demonstrate how some important factors in disassembly can be accommodated to balance a paced disassembly line by modifying the existing concept of assembly line balancing. An example is presented to illustra...
237 citations
TL;DR: The model is shown to provide a lower total cost and shorter lead time compared with those of Banerjee (1986) and Goyal (1988), and is useful for practical inventory problems.
Abstract: The Japanese experience of Just-in-Time (JIT) production has shown that there are advantages and benefits associated with the efforts to reduce inventory lead time and the associated inventory cost. The length of lead time directly affects the customer service level, inventory investment in safety stock, and the competitive abilities of a business. In most of the literature dealing with inventory problems, either a deterministic model or probabilistic model, lead time is viewed as a prescribed constant or a stochastic variable, and is not subject to control. However, in many practical situations, lead time can be reduced by an additional cost. Moreover, the successful implementation of JIT production in today's supply chain enviromnent requires a new spirit of cooperation between the buyer and the vendor (Goyal and Srinivasan 1992). A desirable condition in long time purchase agreements in such a manufacturing environment is the frequent delivry of small quantities of items so as to minimize inventory hol...
223 citations
TL;DR: In this article, a comparative study of lean and agile manufacturing with a related survey of current practices in the UK was carried out, the results of which is presented in this paper.
Abstract: In response to changing success factors and environmental pressures, companies are aspiring to break out of mass production and become lean or agile. Whereas performance enhancements of lean practices have been demonstrated, it is now the case that markets have become increasingly characterized by turbulence, a situation in which reliance on lean practices is insufficient, and that survival requires adoption of agile practices. As a result, a comparative study of lean and agile manufacturing with a related survey of current practices in the UK was carried out, the results of which is presented in this paper. The paper explored the threats to lean and the drivers of agile manufacturing. Using data from a questionnaire survey, four hypotheses were tested, which was indicative of the benefits of agile manufacturing. In contrast to their lean counterparts, agile companies paid attention to a wider range of competitive capabilities. They therefore had a lower range of mean scores on competitive capabilities. I...
213 citations
TL;DR: The paper presents the rationale and principles of a unified language devoted to the area of Enterprise Modelling, which builds on previous languages and provides constructs to cover function/process, information, resource and organization/decision aspects of business entities.
Abstract: The paper presents the rationale and principles of a unified language devoted to the area of Enterprise Modelling. The language, named UEML, for Unified Enterprise Modelling Language, is not intended to replace existing languages but is intended to provide a uniform interface to enterprise modelling tools and a neutral format for exchange of enterprise models. It therefore builds on previous languages and provides constructs to cover function/process, information, resource and organization/decision aspects of business entities. It is also aligned with results of ODP, CEN TC 310, ISO TC 184 and IFAC-IFIP GERAM efforts in the area of enterprise modelling and engineering.
204 citations
TL;DR: In this paper, a novel integer programming formulation with integer programming for steel-making process scheduling is presented. The objective is to ensure continuity of the production process and just-in-time delivery of products.
Abstract: The steel-making process, including steel-making and continuous casting, is usually the bottleneck in iron and steel production. EA ective scheduling of this process is thus critical to improve productivity of the entire production system. Unlike the production scheduling in the machinery industry, steel-making process scheduling is characterized by the following features: job grouping and precedence constraints, set-up and removal times on the machines, and high job waiting costs. These features add extra diA culties to the scheduling problem. The objective is to ensure continuity of the production process and just-in-time delivery of ®nal products. In this paper, a novel integer programming formulation with
TL;DR: In this paper, a hybrid GA and simulated annealing (SA) approach is used to solve the problem of process planning for a prismatic part in a dynamic workshop environment, where the activities of selecting machining resources, determining set-up plans and sequencing machining operations are simultaneously considered.
Abstract: For a CAPP system in a dynamic workshop environment, the activities of selecting machining resources, determining set-up plans and sequencing machining operations should be considered simultaneously to achieve the global lowest machining cost. Optimizing process plans for a prismatic part usually suffer from complex technological requirements and geometric relationships between features in the part. Here, process planning is modelled as a combinatorial optimization problem with constraints, and a hybrid genetic algorithm (GA) and simulated annealing (SA) approach has been developed to solve it. The evaluation criterion of machining cost comes from the combined strengths of machine costs, cutting tool costs, machine changes, tool changes and set-ups. The GA is carried out in the first stage to generate some initially good process plans. Based on a few selective plans with Hamming distances between each other, the SA algorithm is employed to search for alternative optimal or near-optimal process plans. In t...
TL;DR: A two-stage procedure, using a simulated annealing approach, was developed to tackle the mixed-model assembly line balancing problem with parallel workstations and zoning constraints, and the results show that even for large-scale problems the proposed procedure performs very well.
Abstract: This work presents a new mathematical programming model for the mixed-model assembly line balancing problem with parallel workstations and zoning constraints. It allows the user to control the process to create parallel workstations. The model's primary goal is to minimize the number of workstations along the line, for a given cycle time, and its secondary goal is to balance the workloads between and within workstations. A two-stage procedure, using a simulated annealing approach, was developed to tackle this complex problem. The first stage of the procedure looks for a sub-optimal solution to the problem's primary goal, whilst the second stage deals with the secondary goal. The procedure is illustrated with a numerical example and the results from computational experiments show that even for large-scale problems the proposed procedure performs very well.
TL;DR: In this paper, a distance-based fuzzy multicriteria decision-making (MCDM) framework based on the concepts of ideal and anti-ideal solutions is presented for the selection of an FMS from a set of mutually exclusive alternatives.
Abstract: Considering the high required capital outlay and moderate risk of a flexible manufacturing system (FMS) investment, economic justification techniques are insufficient by themselves since they cannot cope with the benefits such as flexibility and enhanced quality offered by advanced manufacturing technologies. A robust decision-making procedure for evaluating FMS requires the consideration of both economic and strategic investment measures. A distance-based fuzzy multicriteria decision-making (MCDM) framework based on the concepts of ideal and anti-ideal solutions is presented for the selection of an FMS from a set of mutually exclusive alternatives. The proposed method provides the means for integrating the economic figure of merit with the strategic performance variables. The multicriteria decision approach presented here enables us to incorporate data in the forms of linguistic variables, triangular fuzzy numbers and crisp numbers into the evaluation process of FMS alternatives. Linguistic variables are...
TL;DR: In this article, the authors focus on the supplier performance evaluation and monitoring process, which assists in maintaining effective customer-supplier linkages, while price has been traditionally considered as the single most important factor in evaluating suppliers, value performance emphasis needs to include other important factors such as quality, delivery an...
Abstract: The purchasing function is central to the strategic operations of effective supply chain management. This centrality is mainly due to the significant impact of material costs on profits, increased investments in inter-organizational advanced manufacturing and information technologies, and a growing emphasis on the just-in-time operations philosophy. The critical business processes of the purchasing function include supplier selection, negotiation of supply contracts, monitoring supplier performance, and acting as an interface between an organization and its suppliers. Within these core processes of purchasing, this paper narrows its scope to focus upon the supplier performance evaluation and monitoring process, which assists in maintaining effective customer-supplier linkages. While price has been traditionally considered as the single most important factor in evaluating suppliers, it has been agreed upon that value performance emphasis needs to include other important factors such as quality, delivery an...
TL;DR: The Innovative Product Development Process (IPDP) as discussed by the authors integrates QFD with TRIZ and enables the effective and systematic creation of technical innovation for new products, where the target products' functions and mechanisms are deployed in parallel into hierarchical structures, and the mechanism that most requires technical innovation is specified from an analysis of customers' needs by calculating a mechanism weight.
Abstract: QFD (Quality Function Deployment) has been used to reflect the needs of customers in products, while TRIZ (a Russian acronym for Theory of Inventive Problem Solving) was developed to assist engineers in finding innovative solutions to technical problems in product development processes. However, no method has been proposed to integrate QFD with TRIZ effectively. This report describes a new method, named the Innovative Product Development Process (IPDP), which systematically integrates QFD with TRIZ and enables the effective and systematic creation of technical innovation for new products. In IPDP, the target products' functions and mechanisms are deployed in parallel into hierarchical structures, and the mechanism that most requires technical innovation is specified from an analysis of customers' needs by calculating a mechanism weight. Then, the technical problems to be solved are defined by considering the relationship between the specified mechanism and corresponding functions or quality characteristic...
TL;DR: In this paper, the authors investigate critical enterprise resource planning (ERP) adoption issues such as adoption motivations, justification, risks and criteria for a selection of product vendor and implementation partners.
Abstract: The study investigates critical enterprise resource planning (ERP) adoption issues such as adoption motivations, justification, risks and criteria for a selection of product vendor and implementation partners. The innovation process study approach is taken and data are collected through a questionnaire and by structured interviews. Although each adopting organization has a distinct set of objectives for its systems, we found many similarities in motivations, concerns and strategies across organizations. The study identifies many critical concerns in the organizational innovation process of ERP adoption.
TL;DR: In this article, the authors proposed a measurement methodology integrating bottom-up and top-down performance measures as a hybrid balanced measurement approach for the supply chain analysis, which is based on both internal and cross-organised business processes.
Abstract: Aside from lean management and business process re-engineering, a new management approach for optimizing logistics organization is gaining recognition: supply chain management.An essential precondition to benefit from supplychain management is a structured analysis of the network-specific optimization opportunities. Opportunities are derived from suboptimal inner- and cross-organisational business processes and the related material, information and capital flows. The paper describes a supply chain analysis approach and proposes a measurement methodology integrating bottom-up and top-down performance measures as a hybrid balanced measurement approach.
TL;DR: In this article, analytical conceptualizing tools based on the features of autonomous vehicle systems are proposed for modelling expected performance as a function of key system attributes including storage capacity, rack configuration and fleet size.
Abstract: Autonomous vehicle storage and retrieval systems utilize rail-guided vehicles moving in rectilinear paths within and between the aisles of unit load storage racks. Vertical vehicle movement is provided by lifts installed at fixed locations along the rack periphery. As an alternative to traditional automated storage and retrieval systems, autonomous vehicle systems enable users to match vehicle fleet size and the number of lifts to the level of transactions demand in a storage system. Analytical conceptualizing tools based on the features of autonomous vehicle systems are proposed for modelling expected performance as a function of key system attributes including storage capacity, rack configuration and fleet size. The models are demonstrated for a sample problem and compared with analytical conceptualizing tools used for automated storage and retrieval systems.
TL;DR: In this paper, an attempt has been made to study the modelling, analysis and tools/techniques used for modelling of BPR with the help of a survey on the recently employed methods and tools used for BPR.
Abstract: Business process design and business process reengineering (BPR) depend crucially on linking production procedures and organizational services to business goals and objectives. There is currently very little formula support for this kind of reasoning as analytical tasks are usually carried out informally and individual design decisions are hard to relate to business objectives. If BPR is carried out without understanding the way it is done, then the most likely outcome would be continuing less-than-satisfactory current practice and automating outdated processes. This kind of practice misses opportunities for innovation and rationalization. The modelling and analysis of business processes along with business strategies and organizational structures are essential to study the implications of BPR. In this paper, an attempt has been made to study the modelling, analysis and tools/techniques used for modelling of BPR with the help of a survey on the recently (1993-2000) employed methods and tools used for BPR ...
TL;DR: In this paper, the advantages and disadvantages of integrating these three systems, as opposed to the systems having independent management in a manufacturing company, are analyzed, and commonalities between the three systems are emphasized.
Abstract: This paper considers the systems of Quality, Environmental and Occupational Health and Safety management. It prospectively analyses the advantages and disadvantages of integrating these systems, as opposed to the systems having independent management in a manufacturing company. Quality Management standards' (ISO 9000) evolution towards Total Quality Management is the starting point. Recent revisions embodied some of the requirements portrayed in the Environmental Management standards (ISO 14000), as well as issues pertaining to Occupational Health and Safety (OHSAS 18001). This tendency towards inclusion of material from different standards systems is expected to be even more evident in the forthcoming revision of the ISO 9000 standards. There is still a notorious absence of an integrated document; ISO has not yet adopted the OHSAS 18001 standard and there are hardships inherent in such an integrative approach. Commonalities between the three systems are emphasized. Foreseen advantages for companies perta...
TL;DR: Numerical results for non-linear examples are shown to be very accurate in comparison with those from Monte Carlo simulations and the first-order reliability method.
Abstract: The experimental design technique in the literature, which has been limited only to normally distributed random variables, is extended to handle non-normal cases. It is easy to implement and provides good results for the moments of system response functions compared with other traditional methods. It is based on the three-level Taguchi method, and optimum levels and weights to handle non-normal distributions are derived. A systematic procedure for tolerance analysis is then proposed by using the Pearson system. Numerical results for non-linear examples are shown to be very accurate in comparison with those from Monte Carlo simulations and the first-order reliability method.
TL;DR: A method based on the mathematical analysis of singularities of linear systems is used to assist in selecting a minimal but sufficient set of link error parameters for the calibration of a machine tool.
Abstract: The position invariant geometric inaccuracies of a machine tool are the first to influence the quality of machined parts. A systematic approach is presented to identify some of these errors on a five-axis machine tool. The methodology is applied to the link error parameters such as joint misalignments, angular offset and rotary axis separation distance. A method based on the mathematical analysis of singularities of linear systems is used to assist in selecting a minimal but sufficient set of link error parameters for the calibration of a machine tool. A number of criteria are proposed in order to verify that the identified parameters accurately predict the positioning errors of the true machine. Finally, the numerical effectiveness of this method is shown through simulations.
TL;DR: In this article, the problem of assigning workers to manufacturing cells in order to maximize the effectiveness of the organization is formulated as a mixed integer programming problem and a total of 32 test problems were developed and varied with regard to the total training time, the available training time for each worker, the training costs, the productivity coefficients and the quality level coefficients.
Abstract: This paper considers the problem of assigning workers to manufacturing cells in order to maximize the effectiveness of the organization. Organization effectiveness is assumed to be a function of the productivity, output quality, and training costs associated with a particular worker assignment. Traditionally, these worker assignments have been based only on the technical skills of the workers. The proposed model also includes human skills and permits the ability to change the skill levels of workers by providing them with additional training. The problem is formulated as a mixed integer programming problem. A total of 32 test problems were developed and varied with regard to the total training time, the available training time for each worker, the training costs, the productivity coefficients and the quality level coefficients. Results indicate that this model provides better worker assignments than one that only considers technical skills.
TL;DR: In this paper, the authors investigate the impact of forecasting errors and information sharing on the performance of a supply chain and show that the expected bias in forecast errors has a much more significant impact on supply chain performance and the value of information sharing.
Abstract: The paper investigates the impact of forecasting errors and information sharing on the performance of a supply chain. It also examines the impact of forecasting errors on the value of information sharing between retailers and a supplier. Analyses of the simulation outputs show that while information sharing can bring tremendous benefits to the supplier and the entire supply chain, it hurts the retailers under most conditions. Demand pattern and forecasting error distributions faced by the retailers significantly influence the magnitudes of the cost savings as a result of information sharing. The expected bias in forecast errors has a much more significant impact on supply chain performance and the value of information sharing than the standard deviation of forecasting errors and its pattern of deterioration over time. A slight positive bias in the retailer's forecast can actually increase the benefit of sharing information for the supplier and the entire supply chain. However, it can also increase the cos...
TL;DR: In this article, the authors extend the recent stream of work in operations strategy on the trade-off and cumulative models of manufacturing capability development using results from the 1996 Manufacturing Futures Survey, and test whether pursuing more capabilities (the cumulative model) is reflected in improved return on assets.
Abstract: The purpose of this research was to extend the recent stream of work in operations strategy on the trade-off and cumulative models of manufacturing capability development Using results from the 1996 Manufacturing Futures Survey, the paper attempts to test whether pursuing more capabilities (the cumulative model) is reflected in improved return on assets We consider both industry and country effects Firms with performance in the upper quartile on a capability are described as 'high' performers and the number of times a firm achieves this level represents the number of capability elements that they have The results show no evidence of the cumulative model Quality and delivery capabilities are nevertheless strongly evident Simply adding more capabilities generally produced no improvement in return on assets Stepwise regression of ROA on the capabilities produced models with good explanatory power in some countries and industries though not all capabilities loaded When interactions between capability
TL;DR: In this paper, a review of the literature on uncertainty under material requirements planning (MRP)-planned manufacture has been carried out and the results of past research work are summarized to give an indication to practitioners of how to cope with uncertainty.
Abstract: Extensive research can be found in coping with uncertainty under Material Requirements Planning (MRP)-planned manufacture, but the under-performance of many manufacturing enterprises is still reported. To examine the reasons, a review of the literature on uncertainty under MRP-planned manufacture has been carried out. This paper presents a comprehensive review and categorisation of such research. It aims to provide a structure within which directions can be given for future research and the results of past research work are summarized to give an indication to practitioners of how to cope with uncertainty. An uncertainty categorization structure has been developed using systems theory to categorize uncertainty into input and process, and simultaneously to highlight the uncertainty that occurs in the supply and demand chain of the manufacturing process. Buffering and dampening (BAD) approaches are proposed and the experimental methods used are incorporated in the structure. A range of research gaps is identified: the lack of a detailed structure to enable the significant uncertainty to be diagnosed optimally, as most of the past research studied uncertainty discretely and only some in specific combinations; the sub-optimal approach in coping with uncertainty; and little research has examined the interactions between uncertainties. Several directions for future research are proposed: the development of a cause-and-effect structure for diagnosing uncertainty, a holistic approach to deduce to the underlying causes of uncertainty, generalization of the cause-and-effect structure, examination of the BAD approaches applied in industry and consideration of interactions between uncertainties by first diagnosing the significant uncertainty. It is found that safety stock, the use of appropriate lot-sizing rules and rescheduling are the most robust approaches to cope with uncertainty, while safety capacity is not used at all for buffering process uncertainty. Hedging/over-planning is useful for dampening process uncertainty. It can be concluded that input uncertainty has been maturely researched with external demand uncertainty dominating others, but with a range of suggested BAD approaches available. Scheduling heuristics, simulation modelling and mathematical modelling are the most applicable experimental methods in this research area. This review and categorization have identified that a structured and systematic approach is required to cope with uncertainty holistically within MRP-planned manufacture.
TL;DR: In this article, four heuristic algorithms for sampling based on the NURBS features of free-form surfaces are presented, and the sampling criteria are equiparametric, surface patch size and the surface patch mean curvature.
Abstract: Coordinate measuring machines (CMMs) are used to examine the conformity of the produced parts with the designer's intent. The inspection of free-form surfaces is a difficult process due to their complexity and irregularity. Many tasks are performed to ensure a reliable and efficient inspection using CMMs. Sampling is an essential and vital step in inspection planning. Efficient and reliable approaches to determine the locations of the points to be sampled from free-form surfaces using the CMM were developed. Four heuristic algorithms for sampling based on the NURBS features of free-form surfaces are presented. The sampling criteria are equiparametric, surface patch size and the surface patch mean curvature. An algorithm for automatic selection of sampling algorithms performs complexity checks on NURBS surfaces, including the surface curvature changes and surface patch size changes, and selects the suitable sampling algorithm. Extensive simulations were performed using the developed methodologies to evalua...
TL;DR: In this article, the authors consider the impacts of the correlation among various characteristics/technical attributes (TA) of products with a view to gaining a higher level of overall customer satisfaction.
Abstract: Quality Function Deployment (QFD) is a well-known customer-oriented methodology that is widely used to assist decision-making in product design and development in various types of production including highly customized One-of-a-Kind Production (OKP), batch production as well as continuous/ mass production. Determining how and to what extent (degree) certain characteristics/technical attributes (TA) of products are to be met with a view to gaining a higher level of overall customer satisfaction is a key to successful product design and development. Most of the existing approaches and models for QFD planning seldom consider the resource constraints in product design, nor do they normally take into account the impacts of the correlation among various TA. In other words, most of the existing QFD applications assume that the resources committed fully to attaining the design target for one TA have no impacts on those for other TA. Hence, the costs/resources required are usually worked out individually by linear...
TL;DR: In this article, a case study was presented that evaluates the impact of partial automation strategies on productivity and ergonomics in a company that partially automated its assembly and transportation functions while moving from a parallel-batch to a serial line-based production system.
Abstract: A case study is presented that evaluates the impact of partial automation strategies on productivity and ergonomics. A company partly automated its assembly and transportation functions while moving from a parallel-batch to a serial line-based production system. Data obtained from company records and key informants were combined with detailed video analysis, biomechanical modelling data and field observations of the system. The new line system was observed to have 51% higher production volumes with 21% less per product labour input and lower work-in-process levels than the old batch-cart system. Partial automation of assembly operations was seen to reduce the total repetitive assembly work at the system level by 34%. Automation of transportation reduced transport labour by 63%. The strategic decision to implement line-transportation was found to increase movement repetitiveness for operators at manual assembly stations, even though workstations were constructed with consideration to ergonomics. Average shoulder elevation at these stations increased 30% and average shoulder moment increased 14%. It is concluded that strategic decisions made by designers and managers early in the production system design phase have considerable impact on ergonomic conditions in the resulting system. Automation of transport and assembly both lead to increased productivity, but only elements related to the automatic line system also increased mechanical loads on operators and hence increased the risk for work-related disorders. Suggestions for integrating the consideration of ergonomics into production system design are made.