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Production Line (production + line)
Selected AbstractsAssessment of working conditions in two different semiconductor manufacturing lines: Effective ergonomics interventionsHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 5 2010Saw Bin Wong Abstract This article examines two manufacturing lines producing semiconductors using different technology concepts, namely Conventional Line (CL) and Lean Production Line (LPL). Both lines manufacturing the same products were compared using various factors, including working conditions, task risks and dangers of the job, and physical body stress. Ergonomic approaches were adopted in the investigation of the two lines. Survey questionnaires were administered to 30% of the workers, and multiple statistical tests were used to determine crucial predictors and to investigate the interactions between the factors. This research has shown that improved ergonomics factors will lead to better working conditions and thus increased job satisfaction. The observed ergonomic differences of these two production lines are compared, and appropriate managerial remedial action is recommended. The interventions to both the lines should reduce accident rates, minimize waste of resources, improve work effectiveness, and provide a better working environment that enhances employees' morale and maximizes productivity and profits. © 2010 Wiley Periodicals, Inc. [source] Intimations of Mortality or Production Lines?POLITICAL PSYCHOLOGY, Issue 3 2009The Puzzle of "Suicide Terrorism" First page of article [source] Coordinated Capacitated Lot-Sizing Problem with Dynamic Demand: A Lagrangian HeuristicDECISION SCIENCES, Issue 1 2004E. Powell Robinson Jr. ABSTRACT Coordinated replenishment problems are common in manufacturing and distribution when a family of items shares a common production line, supplier, or a mode of transportation. In these situations the coordination of shared, and often limited, resources across items is economically attractive. This paper describes a mixed-integer programming formulation and Lagrangian relaxation solution procedure for the single-family coordinated capacitated lot-sizing problem with dynamic demand. The problem extends both the multi-item capacitated dynamic demand lot-sizing problem and the uncapacitated coordinated dynamic demand lot-sizing problem. We provide the results of computational experiments investigating the mathematical properties of the formulation and the performance of the Lagrangian procedures. The results indicate the superiority of the dual-based heuristic over linear programming-based approaches to the problem. The quality of the Lagrangian heuristic solution improved in most instances with increases in problem size. Heuristic solutions averaged 2.52% above optimal. The procedures were applied to an industry test problem yielding a 22.5% reduction in total costs. [source] Cost-benefit analysis of voltage sag mitigation methods in fiber extrusion plantsEUROPEAN TRANSACTIONS ON ELECTRICAL POWER, Issue 2 2003M. Didden The fiber extrusion process is very vulnerable to voltage sags. Being the biggest exporter of carpets in the world, Belgium has many textile fiber extrusion plants. This paper describes the importance of the voltage sag problem in such plants and possible mitigation methods. It turns out that the number of process outages due to voltage sags is less than described in other papers for other geographical grid locations. Still, there are economically attractive mitigation methods. Depending on the manufacturer of the production line, these methods get economically interesting if they mitigate between one and three outages a year. Together with a cost-benefit analysis, this paper-describes the methods that have already been implemented as well as possible future options. [source] A framework for continuous design of production systems and its application in collective redesign of production line equipmentHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 1 2002Françoise Darses The continuous design of production systems is a major challenge facing companies, and one that requires organization and systematization. This article describes one of the continuous design endeavors implemented in a factory manufacturing steel tubes. We have studied the collective redesign of production line equipment. For 2 years, we followed the operations of a multioccupational group composed of the various actors involved in manufacturing (including the operators). Their task was to redesign the tools used in their production line. Our analysis is focused on the cognitive side of the activity and especially on the collective redesign processes. From the transcripts of the meetings, we have examined how the codesigners come to an agreement about the redesigned equipment. We show that the criteria spontaneously used for the evaluation of the solution are far wider (quantitatively and qualitatively) than the list of functional criteria prescribed to the codesigners for the decision-making process. This analysis leads us to propose three conditions that have to be met to guarantee success: (a) a true systemic view of the production system must be developed by all the continuous design actors, (b) there must be support for the collective decision-making process, and (c) new forms of knowledge must be institutionalized. © 2002 John Wiley & Sons, Inc. [source] Physical and mechanical characterization and the influence of cyclic loading on the behaviour of nickel-titanium wires employed in the manufacture of rotary endodontic instrumentsINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2005M. G. A. Bahia Abstract Aim, To analyse the influence of cyclic loading on the mechanical behaviour of nickel-titanium (NiTi) wires employed in the manufacture of ProFile rotary endodontic instruments. Methodology, Nickel-titanium wires, 1.2 mm in diameter, taken from the production line of ProFile rotary endodontic instruments before the final machining step, were tensile-tested to rupture in the as-received condition and after 100 load,unload cycles in the superelastic plateau (4% elongation). The wires were characterized by X-ray energy-dispersive spectroscopy, X-ray diffraction and by differential scanning calorimetry and compared with new size 30, .06 taper ProFile instruments. The fracture surfaces of the wires were observed by scanning electron microscopy. Results, The mechanical properties of the as-received wires, their chemical composition, the phases present and their transformation temperatures were consistent with their final application. Only small changes, which decreased after the first few cycles, took place in the mechanical properties of the cycled wires. The stress at maximum load and the plastic strain at breakage remained the same, while the critical stress for inducing the superelastic behaviour, which is related to the restoring force of the endodontic instruments, decreased by approximately 27%. Conclusions, The mechanical behaviour of the NiTi wires was modified slightly by cyclic tensile loading in the superelastic plateau. As the changes tended towards stabilization, the clinical use of rotary NiTi ProFile instruments does not compromise their superelastic properties until they fracture by fatigue or torsional overload, or are otherwise discarded. [source] Prevalence and characterisation of Bacillus cereus in vacuum packed potato pureeINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2006Andreja Rajkovic Summary Refrigerated processed foods of extended durability (REPFED) potato puree was analysed for Bacillus cereus contamination along the production line and during the product shelf-life. Isolated B. cereus strains were tested for their psychrotrophic character and the ability to produce enterotoxins. Bacillus cereus contamination during four subsequent productions was in the range of 2.3,4.0 log cfu g,1. Productions five and six were significantly less contaminated with B. cereus (,1 log cfu g ,1). All B. cereus isolates from the first four productions were able to grow at 7 ° and 10 °C, whereas the majority of the isolates from productions five and six did not. No B. cereus isolates grew at 4 °C. randomly amplified polymorphic DNA (RAPD) fingerprinting showed that the most of B. cereus contamination originated from one source. In total, 30.4% of isolates expressed enterotoxic character. The present study points out the necessity to prevent an ,in house' colonisation and contamination during food processing in order to accomplish the safety of REPFED throughout the shelf-life. It also indicates the most critical steps in the production line of ready-to-eat potato puree and impact of failures regarding the food safety. The data provided can be used for risk assessment studies regarding B. cereus in REPFED. [source] Micro-organisms and dust exposure in an Italian grain millJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2005C. Dacarro Abstract Aims:, In order to assess possible occupational risk for workers in a grain mill, we evaluated aerial microbiological contamination in different areas of the mill and at different points of the production line. We also measured the concentration of aerodispersed dust particles. Methods and Results:, An assessment of microbiological contamination levels based on a Global Index of Microbial Contamination per cubic metre (GIMC per m3), an Index of Mesophilic Bacterial Contamination, and an Amplification Index is proposed. The indices were obtained from total and fungal counts. The cleaning sector is the most contaminated area of the mill: the mean GIMC per m3 was 17 213·6. In this area, the average microbial contamination was 11·41 times higher than that in the external environment. The highest concentrations of aerodispersed dust (inhalable 2·763 mg m,3; respirable 1·400 mg m,3) were found in the cleaning area. Conclusions:, The proposed microbiological indices and the concentrations of aerodispersed dust particles show that the most hazardous section of the mill is the cleaning area. The large variation in the data does not depend on seasonal factors, but rather on not easily identifiable conditions of the internal environment which facilitate diffusion and/or proliferation of the micro-organisms. Significance and Impact of the Study:, The proposed microbiological contamination indices and the evaluation of the concentration of dust particles allow the identification of critical positions during the production cycle so that suitable measures to prevent the aerial contamination can be taken. [source] Variable selection in random calibration of near-infrared instruments: ridge regression and partial least squares regression settingsJOURNAL OF CHEMOMETRICS, Issue 3 2003Arief Gusnanto Abstract Standard methods for calibration of near-infrared instruments, such as partial least-squares (PLS) and ridge regression (RR), typically use the full set of wavelengths in the model. In this paper we investigate the effect of variable (wavelength) selection for these two methods on the model prediction. For RR the selection is optimized with respect to the ridge parameter, the number of variables and the configuration of the variables in the model. A fast iterative computational algorithm is developed for the purpose of this optimization. For PLS the selection is optimized with respect to the number of components, the number of variables and the configuration of the variables. We use three real data sets in this study: processed milk from the market, milk from a dairy farm and milk from the production line of a milk processing factory. The quantity of interest is the concentration of fat in the milk. The observations are randomly split into estimation and validation sets. Optimization is based on the mean square prediction error computed on the validation set. The results indicate that the wavelength selection will not always give better prediction than using all of the available wavelengths. Investigation of the information in the spectra is necessary to determine whether all of them are relevant to the objective of the model. Copyright © 2003 John Wiley & Sons, Ltd. [source] Vaccine-associated granulomatous inflammation and melanin accumulation in Atlantic salmon, Salmo salar L., white muscleJOURNAL OF FISH DISEASES, Issue 1 2005E O Koppang Abstract The purpose of this study was to investigate the nature of variably sized pigmented foci encountered in fillets of farmed Atlantic salmon, Salmo salar L. The material was sampled on the fillet production line and on salmon farms from fish with an average size of 3 kg from various producers. The fish had been routinely vaccinated by injection. Gross pathology, histology, immunohistochemistry using antisera against major histocompatibility complex (MHC) class II , chain and transmission electron microscopy (TEM) were used to characterize the changes. Macroscopically, melanized foci were seen penetrating from the peritoneum deep into the abdominal wall, sometimes right through to the skin, and also embedded in the caudal musculature. Histological investigation revealed muscle degeneration and necrosis, fibrosis and granulomatous inflammation containing varying numbers of melano-macrophages. Vacuoles, either empty or containing heterogeneous material, were frequently seen. The presence of abundant MHC class II+ cells indicated an active inflammatory condition. TEM showed large extracellular vacuoles and leucocytes containing homogeneous material of lipid-like appearance. The results showed that the melanized foci in Atlantic salmon fillet resulted from an inflammatory condition probably induced by vaccination. The described condition is not known in wild salmon and in farmed salmon where injection vaccination is not applied. [source] The stochastic U-line balancing problemNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 1 2003Franco Guerriero A U-line arranges tasks around a U-shaped production line and organizes them into stations that can cross from one side of the line to the other. In addition to improving visibility and communication between operators on the line, which facilitates problem-solving and quality improvement, U-lines can reduce the total number of operators required on the line and make rebalancing the line easier compared to the traditional, straight production line. This paper studies the (type 1) U-line balancing problem when task completion times are stochastic. Stochastic completion times occur when differences between operators cause completion times to vary somewhat and when machine processing times vary. A recursive algorithm is presented for finding the optimal solution when completion times have any distribution function. An equivalent shortest path network is also presented. An improvement for the special case of normally distributed task completion times is given. A computational study to determine the characteristics of instances that can be solved by the algorithms shows that they are able to solve instances of practical size (like the 114 Japanese and U.S. U-lines studied in a literature review paper). © 2002 Wiley Periodicals, Inc. Naval Research Logistics, 2003 [source] Optimal control of work-in-process inventory of a two-station production line,OPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 3 2010A. Kokangul Abstract Most production lines keep a minimal level of inventory stock to save storage costs and buffer space. However, the random nature of processing, breakdown, and repair times can significantly affect the efficiency of a production line and force the stocking of work-in-process inventory. We are interested in the case when starvation and blockage are preferentially avoided. In this study, a mathematical model has been developed using asymptotic approximation and simulation that provides asymptotic results for the expected value and the variance of the stock level in a buffer as a function of time. In addition, the functional relationship between buffer capacity and the first stopping time caused by starvation or blockage has been determined. Copyright © 2009 John Wiley & Sons, Ltd. [source] Economic Lot Scheduling Problem with ReturnsPRODUCTION AND OPERATIONS MANAGEMENT, Issue 4 2006Ou Tang Motivated by a case study of a company that produces car parts, we study the multi-product economic lot scheduling problem for a hybrid production line with manufacturing of new products and remanufacturing of returned products. For this economic lot scheduling problem with returns (ELSPR), we consider policies with a common cycle time for all products, and with one manufacturing lot and one remanufacturing lot for each product during a cycle. For a given cycle time, the problem is formulated as a mixed integer linear programming (MIP) problem, which provides the basis for an exact solution. The application of this model for one of the core products of the case study company indicates a 16% reduction in cost compared to the current lot scheduling policy. [source] Performance prediction of concentrator solar cells and modules from dark I,V characteristicsPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 3 2003I. Antón The indoor performance of concentrator solar cells and modules at operating conditions is a complex task, owing to the required illumination and temperature conditions, and even more so during extensive procedures, such as on a production line. The solution proposed throughout this paper consists of predicting the illumination I,V characteristic of the solar cells, with the dark I,V curve and the photogenerated current as the only input data. As well as this, the technology-dependent components of the series resistance are obtained from the dark characteristics for quality control. Theory and experiments on several types of concentrator cell have been carried out to validate the method. The equipment to be used on a production line has been developed by IES and used by BP Solar to test up to 25 000 cells and 2000 modules for the 480,kWp power plant using the EUCLIDESTM concentrator. Copyright © 2003 John Wiley & Sons, Ltd. [source] CSR and the environment: business supply chain partnerships in Hong Kong and PRDR, ChinaCORPORATE SOCIAL RESPONSIBILITY AND ENVIRONMENTAL MANAGEMENT, Issue 5 2009Dennis K. K. Cheung Abstract Cross-border relocation of the production lines of Hong Kong companies to the Pearl River Delta Region (PRDR) of China relocates the pollution source geographically. In contextualizing corporate social responsibility (CSR), more and better collaborations on environmental management between Hong-Kong-based companies and their supply chains within Hong Kong and the PRDR are needed. Using a qualitative approach, this research identifies and examines nine concerned business supply chain partnership cases. Stakeholders perceived that partnership is a good tool for improving corporate environmental management. However, although it has become more active since 2002, partnership is not yet popular. More time and support are needed to develop it. Businesses should take further steps to benefit themselves and the environment. Based on the first-hand experiences and opinions of interviewees, this paper analyzes and presents recent partnership activities; their drivers and barriers; factors in their successes; and the possible roles of government and business associations in fostering partnership development. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment. [source] Cushioning the pressure vibration of a zeolite concentrator system using a decoupled balancing duct systemENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2007Feng-Tang Chang Abstract A honeycomb Zeolite Rotor Concentrator (HZRC) is the main air pollution control device utilized by many semiconductor and optoelectronics manufacturers. Various plant exhaust streams are collected and then transferred to the HZRC for decontamination. In a conventional HZRC, the exhaust fan movement and the switching between different air ducts can cause significant duct pressure variations resulting in production interruption. The minimization of pressure fluctuations to ensure continuous operation of production lines while maintaining a high volatile organic compounds (VOCs) removal efficiency is essential for exhaust treatment in these high technology manufactures. The article introduces a decoupled balancing duct system (DBDS) for controlling the airflows to achieve a balanced pressure in the HZRC system by adding a flow rate control device to the VOCs loaded stream bypass duct of a conventional system. Performance comparisons of HZRC with DBDS and other air flow control systems used by the wafer manufacturers in Hsinchu Science Park, Taiwan are presented. DBDS system had been proved effectively to stabilize the pressure in the airflow ducts, and thus avoided pressure fluctuations; it helped to achieve a high VOCs removal efficiency while ensuring the stability of the HZRC. © 2007 American Institute of Chemical Engineers Environ Prog, 2007 [source] Assessment of working conditions in two different semiconductor manufacturing lines: Effective ergonomics interventionsHUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES, Issue 5 2010Saw Bin Wong Abstract This article examines two manufacturing lines producing semiconductors using different technology concepts, namely Conventional Line (CL) and Lean Production Line (LPL). Both lines manufacturing the same products were compared using various factors, including working conditions, task risks and dangers of the job, and physical body stress. Ergonomic approaches were adopted in the investigation of the two lines. Survey questionnaires were administered to 30% of the workers, and multiple statistical tests were used to determine crucial predictors and to investigate the interactions between the factors. This research has shown that improved ergonomics factors will lead to better working conditions and thus increased job satisfaction. The observed ergonomic differences of these two production lines are compared, and appropriate managerial remedial action is recommended. The interventions to both the lines should reduce accident rates, minimize waste of resources, improve work effectiveness, and provide a better working environment that enhances employees' morale and maximizes productivity and profits. © 2010 Wiley Periodicals, Inc. [source] Tracing Salmonella in Alheira processing plantsJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007A. Esteves Abstract Aims:, To investigate the sources of Salmonella spp. in Alheira and how to trace it, by studying the way that Salmonella spp. is distributed across production lines, by applying multifactorial correspondence analysis to occurrence data, and through the use of polymerase chain reaction (PCR) molecular typing methods. Methods and Results:, Four production lines, four batches of Alheira and 14 sampling sites were analysed over four sampling periods. Eighty-five Salmonella spp. isolates were obtained from the 896 microbial analyses performed. The basic occurrence analysis values, multiple correspondence analysis and PCR molecular typing methods confirmed that the presence of Salmonella spp. in Alheira was directly related to it being present in casings. Results obtained from PCR molecular typing added a measure of detail, highlighting potential cross-path contamination caused by contaminated surfaces. Conclusions:, The presence of Salmonella spp. in Alheira was a result of the use of contaminated casings, as well as cross-path contamination caused by contaminated surfaces. An analysis of the occurrence data indicated that these casings were the source of Salmonella spp. contamination in Alheira. PCR molecular typing methodology, which is known to have a greater discriminatory power and tracing capacity, indicated the presence of cross-path contamination. Significance and Impact of this Study:, Increased awareness of Salmonella spp. contamination sources and their spread across the production line helps shape the development of new strategies for controlling this pathogen. [source] Plate-out in PVC extrusion.JOURNAL OF VINYL & ADDITIVE TECHNOLOGY, Issue 1 2008Samples of extruder plate-out from industrial rigid PVC production lines were investigated by using a number of analytical techniques. The combined use of SEM-EDX (scanning electron microscopy , energy dispersive X-ray analysis), thermal analysis, FTIR (Fourier transform infrared spectrophotometry), and LIMA (laser-induced mass analysis) enabled most plate-out components to be identified and linked to likely formulation ingredients. The FTIR and thermal analyses were used to identify organic components. The FTIR analysis was also useful for identifying some inorganic compounds present in sufficient quantities, while EDX detected the elements present. The LIMA was the most sensitive technique, detecting trace quantities of both cations and anions. Calcium carbonate, titanium dioxide, and lead stabilizers were found in all die plate-out samples studied, together with small amounts of lubricants. J. VINYL ADDIT. TECHNOL., 2008. © 2008 Society of Plastics Engineers. [source] High-Efficiency Silicon Solar Cells Demand New Process ToolsLASER TECHNIK JOURNAL, Issue 1 2010Laser-Based Process Tools for c-Si Manufacturing are on the Rise Laser-based tools are becoming an essential part of new crystalline silicon cell lines which are configured for high-efficiency performance. Different tooling types are required on a case-by-case basis, depending on the level of process development undertaken and how fast cell producers move to implement the laserbased tools within high-throughput production lines. [source] Design and control of agile automated CONWIP production linesNAVAL RESEARCH LOGISTICS: AN INTERNATIONAL JOURNAL, Issue 1 2009Wallace J. Hopp Abstract In this article, we study the design and control of manufacturing cells with a mix of manual and automated equipment, operating under a CONWIP pull protocol, and staffed by a single agile (cross-trained) worker. For a three-station line with one automated station, we fully characterize the structure of the optimal control policy for the worker and show that it is a static priority policy. Using analytical models and extensive simulation experiments, we also evaluate the effectiveness of practical heuristic control policies and provide managerial insights on automation configuration design of the line. This characterization of the worker control policy enables us to develop managerial insights into the design issues of how best to locate and concentrate automation in the line. Finally, we show that, in addition to ease of control and greater design flexibility, the CONWIP protocol also offers higher efficiency and robustness than does the push protocol. © 2008 Wiley Periodicals, Inc. Naval Research Logistics 2009 [source] Optimal control of work-in-process inventory of a two-station production line,OPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 3 2010A. Kokangul Abstract Most production lines keep a minimal level of inventory stock to save storage costs and buffer space. However, the random nature of processing, breakdown, and repair times can significantly affect the efficiency of a production line and force the stocking of work-in-process inventory. We are interested in the case when starvation and blockage are preferentially avoided. In this study, a mathematical model has been developed using asymptotic approximation and simulation that provides asymptotic results for the expected value and the variance of the stock level in a buffer as a function of time. In addition, the functional relationship between buffer capacity and the first stopping time caused by starvation or blockage has been determined. Copyright © 2009 John Wiley & Sons, Ltd. [source] Modelling capping of 28,mm beverage closures using finite element analysisPACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2008J. Rowson Abstract Understanding the performance of packaging on production lines is of course extremely important to the packaging industry. Computer simulation techniques have improved vastly in recent years, and modelling the complex interaction of three-dimensional threaded shapes, like closures, is now a reality. This paper outlines the work undertaken in understanding the possible mechanisms relating to the capping of 28,,mm beverage closures and the use of experimental and computer simulations in order to establish that understanding. Copyright © 2007 John Wiley & Sons, Ltd. [source] Introduction of flexible packaging systems for toiletry productsPACKAGING TECHNOLOGY AND SCIENCE, Issue 5 2001Yuji Ikeda Abstract Flexible manufacturing systems (FMS) are rapidly gaining in importance for manufacturers throughout the industrialized world. Lion Corporation is no exception in its need of FMS because of the great variety of toiletry and household products it produces. Toiletry products, such as toothpaste, detergent and shampoo, are our mainstay products, which account for 75% of our total sales. On our production lines, therefore, it is essential that they can be changed flexibly for the manufacture of ever-changing products. Introduced in this report are some of our flexible packaging systems, which use carriers, robots, standardized shampoo bottles, etc., without relying on special tools or new parts for line change. Innovation of our flexible packaging systems for greater flexibility and cost reduction will continue in the future. Copyright © 2001 John Wiley & Sons, Ltd. [source] Screen-printed epitaxial silicon thin-film solar cells with 13·8% efficiencyPROGRESS IN PHOTOVOLTAICS: RESEARCH & APPLICATIONS, Issue 8 2003J. Rentsch Abstract Amidst the different silicon thin-film systems, the epitaxial thin-film solar cell represents an approach with interesting potential. Consisting of a thin active c-Si layer grown epitaxially on top of a low-quality c-Si substrate, it can be implemented into solar cell production lines without major changes in the current industrial process sequences. Within this work, ,30-,m-thick epitaxial layers on non-textured and highly doped monocrystalline Czochralski (Cz) and multicrystalline (mc) Si substrates have been prepared by CVD. Confirmed efficiencies of 13·8% on Cz and 12·3% on mc-Si substrates have been achieved by applying an industrial process scheme based on tube and in-line phosphorus diffusion, as well as screen-printed front and back contacts fired through a SiNx anti-reflection coating. An extensive solar cell characterisation, including infrared lock-in thermography and spectral response measurements is presented. Copyright © 2003 John Wiley & Sons, Ltd. [source] Generalized confidence intervals for assessing process capability of multiple production linesQUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 6 2009Chien-Wei Wu Abstract Process capability indices (PCIs) have become popular as unit-less measures on whether a process is capable of reproducing items meeting the quality requirement. A reliable approach for testing process capability is to establish an interval estimate, for which we can assert that it contains the true PCI value with a reasonable degree of certainty. However, the construction of such an interval estimate is not trivial, since the distribution of the commonly used Cpk index involves unknown parameters. In this paper, we adopt the concept of generalized confidence intervals and generalized pivotal quantities to derive the generalized lower confidence bounds for providing critical information on process performance. Two practical applications in the area of process capability were considered, they include (i) assessing whether a process under investigation is capable and (ii) providing the lowest performance of the manufacturing processes from several production lines or several suppliers for quality assurance. The applicability of the derived results is also illustrated with examples. Copyright © 2008 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||