ISSN:0748-8017    

DOI:10.1002/qre.4680050202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractMr Basil Butler, Managing Director of the British Petroleum Company plc, recently addressed a meeting of the British Institute of Management on the subject of safety and how it relates to profits. In our view, it was an excellent speech which deserves a wider audience and should be of particular interest to practising quality and reliability engineers.The Editors are indebted to Mr Butler and to BP for permission to publish the address in full.

ISSN:0748-8017    

DOI:10.1002/qre.4680050203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractAn investigation has been carried out in thirteen suppliers of plant systems and equipment for one‐off construction projects, to determine the benefits and problems of applying quality assurance. This paper reports the findings of the investigation. These suppliers and the major purchasing agents are confronted with special quality assurance problems such as multiple auditing and inspection which are allied to the one‐off nature of the items supplied. It is pointed out that this sample of suppliers is commonly encountering four to five external audits each year and that there is some dissatisfaction with the professional competence of some auditors and many inspectors employed on non‐nuclear cont

ISSN:0748-8017    

DOI:10.1002/qre.4680050204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractDesign of experiments is a quality technology to achieve product excellence, that is to achieve high quality at low cost. It is a tool to optimize product and process designs, to accelerate the development cycle, to reduce development costs, to improve the transition of products from R&D to manufacturing and to troubleshoot manufacturing problems effectively. It has been successfully, but sporadically, used in the United States. More recently, it has been identified as a major technological reason for the success of Japan in producing high‐quality products at low cost.In the United States, the need for increased competitiveness and the emphasis on quality improvement demands a widespread use of design of experiments by engineers, scientists and quality professionals. In the past, such widespread use has been hampered by a lack of proper training and a lack of availability of tools to easily implement design of experiments in industry.Three steps are essential, and are being taken, to change this situation dramatically. First, simple graphical methods, to design and analyse experiments, need to be developed, particularly when the necessary microcomputer resources are not available. Secondly, engineers, scientists and quality professionals must have access to microcomputer‐based software for design and analysis of experiments.1Availability of such software would allow users to concentrate on the important scientific and engineering aspects of the problem by computerizing the necessary statistical expertise. Finally, since a majority of the current workforce is expected to be working in the year 2000, a massive training effort, based upon simple graphical methods and appropriate computer software, is necessary.2The purpose of this paper is to describe a methodology based upon a new graphical method called interaction graphs and other previously known techniques, to simplify the correct design of practically important fractional factorial experiments. The essential problem in designing a fractional factorial experiment is first stated. The interaction graph for a 16‐trial fractional factorial design is given to illustrate how the graphical procedure can be easily used to design a two‐level fractional factorial experiment. Other previously known techniques are described to easily modify the two‐level fractional factorial designs to create mixed multi‐level designs. Interaction graphs for other practically useful fractional factorial designs are provided. A computer package called CADE (computer aided design of experiments), which automatically generates the appropriate fractional factorial designs based upon user specifications of factors, levels and interactions and conducts complete analyses of the designed experiments is briefly described.1Finally, the graphical method is compared with other available methods for designing fractional factorial

ISSN:0748-8017    

DOI:10.1002/qre.4680050205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe use of plastic encapsulated devices (PEDs) for a variety of market sectors has been the subject of much discussion over the past two decades. The advantages of lower cost together with the inherent mechanical ruggedness of these non‐cavity packages have been weighed against the concerns over quality and reliability and, in particular, electrical operation at extremes of temperature. This paper presents the results of some practical work undertaken on a modern LSI device in a plastic leaded chip carrier package. It then discusses British Telecom's experience with PEDs to date and concludes with some general considerations on the quality assurance requirements a purchaser may place on vendors of such device

ISSN:0748-8017    

DOI:10.1002/qre.4680050206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe performance of a pressure‐surge relief system which acts as a safety mechanism within the export facility of an oil terminal is analysed in detail. Dynamic simulation methods are integrated with failure mode effects analysis to establish the risk of catastrophic failure of the terminal. An optimization procedure is presented which demonstrates the use of simulation to establish suitable inspection, testing and preventive maintenance schedules which maximize the effectiveness of the surge relief system over its design life. The importance of such activities is evident — left unattended the surge‐relief system will not meet minimum safety standards, whereas planned maintenance and testing is shown to improve safety standards above the minimum req

ISSN:0748-8017    

DOI:10.1002/qre.4680050207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractOne of the key issues in statistical process control (SPC) is the forming ‘rational subgroups’. Rational subgroups are defined as1Subgroups displaying only random within‐variation.2Subgroups having small within‐variation to compare with variation between subgroups.In a previous paper1we developed an approach of choosing the proper subgroup size for control charts for statistical process control. The approach is particularly appropriate for batch industries where some batch‐to‐batch variation is to be expected and should be accommodated. In this paper we will deal with the question of whether or not subgroups are rational. A randomness test can be used to verify rationality. The measure selected is the ratio of several different variance estimators. An example is provided to demonstrate the application of

ISSN:0748-8017    

DOI:10.1002/qre.4680050208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThe expected number of circuit pack failures is an important input to the accurate planning of the inventory level of spares. The failure rate of a circuit pack depends on its age and is generally higher during the infant mortality period (frequently one year) as compared to the steady‐state period. In some of the existing models, it is assumed that all of the defective circuit packs are replaced with new circuit packs. On the other extreme, some models assume that each of the defective circuit packs is repaired and shipped back to the field. Depending on the modelling assumption, the estimates of expected number of failures can differ by as much as 15 per cent. The Markov process model described in this paper includes a parameter (fraction of non‐repairable circuit packs) which permits us to investigate cases where only a portion of the circuit packs are non‐repairable (i.e. need to be replaced with new circuit packs). The model estimates the expected number of failures based on the infant mortality rate, the steady‐state failure rate, age distribution of the installed circuit packs, growth potential and fraction of non‐repairable circ

ISSN:0748-8017    

DOI:10.1002/qre.4680050209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractFor the prediction of product reliability from test structure data the observed times to failure have to be fitted to an assumed probability distribution and extrapolated to small failure probabilities. And the probability distribution for the (small) test structure size has to be extrapolated to the corresponding distribution for the (larger) product size.With respect to the probability distribution it is shown that even in the ‘defect’ dominated case, extreme value distributions do not have to apply. This leads to considerable extrapolation uncertainties.For the size extrapolation of test structure data to the product the degree of dependence between times to failure of substructures on the same chip is of crucial importance. It can change the predicted reliability by orders of magnitude. A model describing this dependence is given and analyses yielding the required information are sugges

ISSN:0748-8017    

DOI:10.1002/qre.4680050210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY

摘要:

AbstractThis paper reports on research which examined the use of statistical process control (SPC) in the quality improvement process of a printed circuit board (PCB) manufacturer. The implementation of SPC is discussed along with the difficulties encountered and benefits achieved. The findings indicate that SPC is a tool which can be of considerable assistance in the quality improvement process of PCB manufacture. However, the variety of manufacturing technologies used and the number of interconnecting processes makes the application of SPC more difficult than in other traditional industries. The lessons learned include that the introduction of SPC must not be rushed, that discipline and support from all levels in the organization are crucial to its success, that SPC cannot be used in isolation—it needs the structure of a continuous improvement initiative, and that getting processes in a state of statistical control and capable, and keeping them there, is a difficult task which involves considerable effort and patienc

ISSN:0748-8017    

DOI:10.1002/qre.4680050211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1989

数据来源: WILEY