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Connie M. Borror 《Quality and Reliability Engineering International》2011,27(4):479-487
In this paper, we review two common measurement system indices and a common process capability index. With some simple plots, it will be shown that the traditional guidelines for these measurement system indices can often misdirect improvement efforts. By taking advantage of the relationship between the measurement system indices and the process capability index, two‐dimensional guidelines that can be used as an alternative to the traditional guidelines are developed. These two‐dimensional guidelines are intended to help address adequacy of the measurement system and better direct improvement efforts to where there will be the most benefit. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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多元测量系统分析是多元质量控制的重要内容。现有的研究主要是利用统计学的方法,如多元方差分析法和主成分法等进行分析评价。本文提出了基于量纲分析的多元测量系统能力评价方法,集成物理和统计分析方法,利用物理中量纲分析的方法研究产品各相关变量之间的物理关系,将多元测量系统问题转化为一元测量系统问题。从而可以利用一元测量系统能力评价的统计方法及指标来对测量系统的能力进行评估。同时,本文重复了纸飞机试验,并运用基于量纲分析的多元测量系统能力评价方法对纸飞机的测量系统进行了分析评价,验证了该方法的有效性。 相似文献
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《Quality Engineering》2012,24(3):290-299
ABSTRACT Process Capability Indices, such as Cp and Cpk have been widely used as statistical tools to assess the manufacturing process performance. These indices provide numerical measures on process precision, process accuracy and process performance. Extensive researches have been done on the univariate process capability indices in the last two decades. However, process capability indices for processes with multiple quality characteristics have received little attention, comparatively. The multivariate process capability indices, which are used for evaluation of processes with correlated quality characteristics such as weight, height and width, could be investigated, in depth. In this research the concept of process capability and its relevant indices in univariate and multivariate cases are discussed. Based on the previous works, a new multivariate process capability vector (NMPCV) is introduced. This vector is based on a modification of the traditional multivariate process capability indices. The value and the power of this new index are evaluated using field and simulated data. The results of this research show that NMPCV is a better tool for judging the process accuracy, the process precision and the process performance. When the characteristics are highly correlated, the results are much better. 相似文献
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《Quality Engineering》2012,24(1):21-29
ABSTRACT Inspection systems measure every part produced. If the measurement is outside of the inspection limits, then that part is measured again. To assess the quality of these measurement systems, traditionally gauge repeatability and reproducibility (R&R) studies are preformed. Instead of performing a gauge R&R study, we present a method of assessing these measurement systems with operational data from an inspection system. Using the inspection data, we provide a justification for the pooled variance of the measured values for each part that has two measurements. The bias and variance of this analysis of variance (ANOVA) estimator are derived using properties of the truncated normal distribution. We show that the ANOVA estimator has a relatively small bias and high efficiency when compared with the maximum likelihood estimator for most common values of γ or GRR%, which is the measurement system standard deviation divided by total inspection system standard deviation. 相似文献
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轴瓦厚度测量机稳定性的测量分析 总被引：1，自引：0，他引：1
介绍了轴瓦厚度测量系统分析计划的制订,测量系统偏倚特性、稳定性和线性分析.对测量系统的重复性与再现性分析步骤、计算过程、分析结果做了详尽的剖析与讨论.认为自行开发研制的轴瓦厚度测量机的偏倚特性、稳定性和线性能满足测量要求,其重复性与再现性指标R&R%<30%,基本上具有所需的测量能力. 相似文献
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Lucian Dascalescu Khouira Senouci Marius‐Cristian Plopeanu Alexandra Rotaru Sorin Cananau Karim Medles 《Quality and Reliability Engineering International》2014,30(4):601-611
The system currently employed for measuring the electric potential of the surface of textile fabrics consists in an electrostatic probe connected to an electrostatic voltmeter. The primary aim of the present work is to improve the capability of this measurement system, as evaluated by gauge repeatability and reproducibility studies. The experiments were conducted on samples of polypropylene non‐woven fabrics, electrostatically charged by exposing them to a negative corona discharge from a custom‐designed electrode system. A first series of fully operator‐controlled measurements pointed out the need to automatically control the relative position between the sample and probe, so that to eliminate the variability due to the non‐uniform structure of the non‐woven fabrics. The following series of partly automated experiments revealed that the repeatability and the reproducibility of the measurements are negatively affected by the decay of the electric potential at the surface of the samples. The best gauge capability is obtained when the measurements are delayed with respect to the moment of corona charging, in order to reduce the variability due to the fact that the samples characteristics change in time. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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本文介绍测量系统分析的一般概念,探讨、研究曲轴测量机这一测量系统所涉及的偏倚、线性、稳定性、重复性等一系列问题,提出在实际生产现场评定曲轴测量机的方法。 相似文献
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A new method is proposed for the attribute gauge study. A mathematical model based on the Gauge Performance Curve (GPC) is introduced and the connection between the model parameters and gauge characteristics is discussed. The ability of the whole measurement system (the process and the gauge together) is characterized by two key probabilities: the probability of a rejected part being good and the probability of an accepted part being bad. These probabilities can be calculated either with the proposed mathematical model of GPC (GPC‐method) or by using relative frequencies (AIAG‐type method). The performance of the two approaches has been compared, and the proposed GPC‐method is proven to be statistically favourable. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Graeme Knowles Gordon Vickers Jiju Anthony 《Quality and Reliability Engineering International》2003,19(5):397-410
Reducing process variability is presently an area of much interest in manufacturing organizations. Programmes such as Six Sigma robustly link the financial performance of the organization to the degree of variability present in the processes and products of the organization. Data, and hence measurement processes, play an important part in driving such programmes and in making key manufacturing decisions. In many organizations, however, little thought is given to the quality of the data generated by such measurement processes. By using potentially flawed data in making fundamental manufacturing decisions, the quality of the decision‐making process is undermined and, potentially, significant costs are incurred. Research in this area is sparse and has concentrated on the technicalities of the methodologies available to assess measurement process capability. Little work has been done on how to operationalize such activities to give maximum benefit. From the perspective of one automotive company, this paper briefly reviews the approaches presently available to assess the quality of data and develops a practical approach, which is based on an existing technical methodology and incorporates simple continuous improvement tools within a framework which facilitates appropriate improvement actions for each process assessed. A case study demonstrates the framework and shows it to be sound, generalizable and highly supportive of continuous improvement goals. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
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《Quality Engineering》2012,24(3):361-368
Confidence intervals are usually constructed to assess the levels of precision in method validation studies. Frequently, these confidence intervals are constructed assuming that the random errors come from infinite populations. In practice, the random errors are selected from a finite population of known size. In these cases, the infinite population model provides confidence intervals that are too wide. A fixed effects model underestimates the measures of precision. In this article, confidence intervals for measures of precision are developed in an interlaboratory study with labs selected from a finite population of known size. 相似文献
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李亮波;王雪;李海蓉;郭海;朱新旺 《计量科学与技术》2024,68(4):71-78
电能计量器具自动化检定流水线长期在线高负荷运行,会发生性能退化甚至出现故障,导致电能测量误差试验结果出现偏差。为准确掌握电能计量器具自动化检定流水线测量系统波动规律,确定来自测量系统的总变化量以及各变量的差异,提高测量系统的准确性与可靠性,设计了流水线测量系统分析方案。在分析流水线结构特点和工作原理的基础上,提出一种全新的实验设计方案,并制定了测量系统分析计划。以低压电流互感器自动化检定流水线为例,对测量系统重复性和再现性、偏倚和线性、稳定性三个指标进行了分析。分析结果表明,测量系统的变异占合计变异的1.67%,变异指标%GR & R为18.21%,偏倚占比5.4%,线性占比8.7%,可区分的类别数7,测量系统具备所需的测量能力,处于条件接受状态。进一步分析变异的来源,再现性是主要的变异因素,测量系统在不同工位上的一致性存在显著差异。最后,结合测量系统分析结果、生产现场管理和运维经验,对流水线测量系统的改进提出建议。 相似文献
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微光像增强器信噪比测试技术研究 总被引：1，自引：1，他引：1
对一台进口的微光像增强器信噪比 (SNR)测试仪进行了改造 ,重新研制和设计了测试仪的信号处理模块、计算机系统和测试软件 ,采用硬件滤波、软件数字滤波和快速傅立叶变换 (FFT)相结合的方法实现了像增强器信噪比测试。利用研制的测试仪对多种型号的像增强器的信噪比进行了测试 ,给出并分析了测试结果。 相似文献
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Peter H. Huang Raghu Kacker 《Journal of research of the National Institute of Standards and Technology》2003,108(3):235-240
Permeation-tube moisture generators are used in industry as calibrated sources of water vapor and carrier gas mixtures. Measurements were made using three permeation-tube moisture generators of the type used in the semiconductor industry. This paper describes repeatability and reproducibility standard deviations in measurement of moisture concentration from such generators. Repeatability refers to measurements within a system and reproducibility refers to measurements between systems. Two independent methods were used to measure the realized concentration of water vapor. The first measurement, the calculated value, was determined using calibrated permeation rate of permeation-tube and flow rate of dry carrier gas. This is the industrial method of evaluating moisture concentration. The second measurement, the measured value, was determined using the low frost-point generator at the National Institute of Standards and Technology (NIST) and a quartz-crystal-micro-balance. Four pairs of independent measurements for each generator and for six nominal levels in the range from10 nL/L to 100 nL/L were made. The characteristic used to quantify repeatability and reproducibility standard deviations in industrial measurements is the calculated value minus the measured value. Repeatability standard deviation ranges from 1 nL/L to 2 nL/L, approximately. Reproducibility standard deviation ranges from 2 nL/L to 8 nL/L, approximately. The documentary ASTM standard E691-99 was used for both data validation and quantification of the repeatability and reproducibility standard deviations. 相似文献
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Souha Ben Amara Jamel Dhahri Nabil Ben Fredj 《Quality and Reliability Engineering International》2017,33(5):937-944
Process capability indices are widely computed under the assumption that the measurement system is free from errors. However, measurement variability is unavoidable and has a significant impact in process capability evaluation. From an economic point of view, Taguchi loss function is an effective tool to measure the quality loss of a product characteristic deviated from target value that is extensively used without taking into account the effect of the measurement system. This paper investigates the influence of measurement system variability on the process capability analysis through the calculation of process capability indices. A new quality loss function, integrating the measurement system errors, is developed to compute the optimal true process capability regarding to the expected mean value of the Taguchi loss function and the loss resulting from the control of the true process capability. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献