Reliability allocation of computerized numerical controlled（CNC）lathes is very important in industry.Traditional allocation methods only focus on high-failure rate components rather than moderate failure rate compon...Reliability allocation of computerized numerical controlled（CNC）lathes is very important in industry.Traditional allocation methods only focus on high-failure rate components rather than moderate failure rate components,which is not applicable in some conditions.Aiming at solving the problem of CNC lathes reliability allocating,a comprehensive reliability allocation method based on cubic transformed functions of failure modes and effects analysis（FMEA）is presented.Firstly,conventional reliability allocation methods are introduced.Then the limitations of direct combination of comprehensive allocation method with the exponential transformed FMEA method are investigated.Subsequently,a cubic transformed function is established in order to overcome these limitations.Properties of the new transformed functions are discussed by considering the failure severity and the failure occurrence.Designers can choose appropriate transform amplitudes according to their requirements.Finally,a CNC lathe and a spindle system are used as an example to verify the new allocation method.Seven criteria are considered to compare the results of the new method with traditional methods.The allocation results indicate that the new method is more flexible than traditional methods.By employing the new cubic transformed function,the method covers a wider range of problems in CNC reliability allocation without losing the advantages of traditional methods.展开更多
With the widespread application of liquefied petroleum gas (LPG),the safety of LPG cylinder has received more and more attention.For the safety of LPG cylinder,we conduct a safety risk assessment of cylinder using the...With the widespread application of liquefied petroleum gas (LPG),the safety of LPG cylinder has received more and more attention.For the safety of LPG cylinder,we conduct a safety risk assessment of cylinder using the failure mode and effect analysis (FMEA) method.Taking the most influential inflatable fatigue under normal conditions as the research object,we use FE-safe software to analyze the fatigue failure.The risk compliance coefficients of various failure modes are calculated and classified according to the risk level.In this way,the service life of the LPG cylinder weld is determined.The presented method improves the safety risk assessment process of LPG cylinder and provides a good theoretical and practical basis for similar pressure vessel risk assessment.展开更多
The objective of this work was to enhance the product’s quality by concentrating on the machine’s optimized efficiency.In order to increase the machine’s reliability,the basis of reliability-centered maintenance ap...The objective of this work was to enhance the product’s quality by concentrating on the machine’s optimized efficiency.In order to increase the machine’s reliability,the basis of reliability-centered maintenance approach was utilized.The purpose was to establish a planned preventive maintenance strategy to identify the machine’s critical components having a noteworthy effect on the product’s quality.The critical components were prioritized using failure mode and effect analysis(FMEA).The goal of the study was to decrease the ppm time interval for a CNC machine by simulating the projected preventive maintenance time interval.For this purpose,the simulation software ProModel 7.5 was implemented for the current preventive maintenance procedure to choose the best ppm time interval which contributed better norms.Five dissimilar optimization approaches were applied,however,the first approach yielded the prominent total system cost and the shorter ppm interval.The results of the study revealed that there was an increase of USD 1878 as a result of an increase in total system cost from USD 78,365 to USD 80,243.Preventive maintenance costs were reduced from USD 4196 to USD 2248(46%).The costs associated with good parts increased from USD 8259 to USD 8294(0.4%)and the costs associated with defective parts reduced from USD 171 to USD 3(98.25%),respectively.展开更多
随着临床风险管理成为医院管理的一个重要组成部分，降低医疗差错、确保患者安全已成为质量管理的一个重要过程。失效模式和效应分析（failure mode and effectanalysis，FMEA）是发现并减少医疗差错的一个重要的前瞻性方法。在简要回顾...随着临床风险管理成为医院管理的一个重要组成部分，降低医疗差错、确保患者安全已成为质量管理的一个重要过程。失效模式和效应分析（failure mode and effectanalysis，FMEA）是发现并减少医疗差错的一个重要的前瞻性方法。在简要回顾FMEA发展历史的基础上，详细描述FMEA的实施方法和步骤，重点介绍FMEA应用于降低医院医疗差错的研究进展。展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.51135003,51205050,U1234208)Key National Science & Technology Special Project on"High-Grade CNC Machine Tools and Basic Manufacturing Equipments"(Grant No.2013ZX04011011)+1 种基金Research Fund for the Doctoral Program of Higher Education of China(Grant No.20110042120020)Fundamental Research Funds for the Central
文摘Reliability allocation of computerized numerical controlled（CNC）lathes is very important in industry.Traditional allocation methods only focus on high-failure rate components rather than moderate failure rate components,which is not applicable in some conditions.Aiming at solving the problem of CNC lathes reliability allocating,a comprehensive reliability allocation method based on cubic transformed functions of failure modes and effects analysis（FMEA）is presented.Firstly,conventional reliability allocation methods are introduced.Then the limitations of direct combination of comprehensive allocation method with the exponential transformed FMEA method are investigated.Subsequently,a cubic transformed function is established in order to overcome these limitations.Properties of the new transformed functions are discussed by considering the failure severity and the failure occurrence.Designers can choose appropriate transform amplitudes according to their requirements.Finally,a CNC lathe and a spindle system are used as an example to verify the new allocation method.Seven criteria are considered to compare the results of the new method with traditional methods.The allocation results indicate that the new method is more flexible than traditional methods.By employing the new cubic transformed function,the method covers a wider range of problems in CNC reliability allocation without losing the advantages of traditional methods.
文摘With the widespread application of liquefied petroleum gas (LPG),the safety of LPG cylinder has received more and more attention.For the safety of LPG cylinder,we conduct a safety risk assessment of cylinder using the failure mode and effect analysis (FMEA) method.Taking the most influential inflatable fatigue under normal conditions as the research object,we use FE-safe software to analyze the fatigue failure.The risk compliance coefficients of various failure modes are calculated and classified according to the risk level.In this way,the service life of the LPG cylinder weld is determined.The presented method improves the safety risk assessment process of LPG cylinder and provides a good theoretical and practical basis for similar pressure vessel risk assessment.
基金This research is fully supported by HEC Grant of Research for publishing scientific articles.The authors fully acknowledge support from Sarhad University of Science and Information Technology for the approved fund which makes this research viable and effective.
文摘The objective of this work was to enhance the product’s quality by concentrating on the machine’s optimized efficiency.In order to increase the machine’s reliability,the basis of reliability-centered maintenance approach was utilized.The purpose was to establish a planned preventive maintenance strategy to identify the machine’s critical components having a noteworthy effect on the product’s quality.The critical components were prioritized using failure mode and effect analysis(FMEA).The goal of the study was to decrease the ppm time interval for a CNC machine by simulating the projected preventive maintenance time interval.For this purpose,the simulation software ProModel 7.5 was implemented for the current preventive maintenance procedure to choose the best ppm time interval which contributed better norms.Five dissimilar optimization approaches were applied,however,the first approach yielded the prominent total system cost and the shorter ppm interval.The results of the study revealed that there was an increase of USD 1878 as a result of an increase in total system cost from USD 78,365 to USD 80,243.Preventive maintenance costs were reduced from USD 4196 to USD 2248(46%).The costs associated with good parts increased from USD 8259 to USD 8294(0.4%)and the costs associated with defective parts reduced from USD 171 to USD 3(98.25%),respectively.
文摘随着临床风险管理成为医院管理的一个重要组成部分，降低医疗差错、确保患者安全已成为质量管理的一个重要过程。失效模式和效应分析（failure mode and effectanalysis，FMEA）是发现并减少医疗差错的一个重要的前瞻性方法。在简要回顾FMEA发展历史的基础上，详细描述FMEA的实施方法和步骤，重点介绍FMEA应用于降低医院医疗差错的研究进展。
