共查询到20条相似文献,搜索用时 15 毫秒
1.
Yanjing Ou Zhang Wu Songlin Chen Ka Man Lee 《The International Journal of Advanced Manufacturing Technology》2010,51(9-12):1045-1054
The sequential probability ratio test (SPRT) chart is a desirable tool for monitoring manufacturing processes due to its high effectiveness. It is especially suitable for applications where testing is very expensive or destructive, such as the automobile airbags test and unaxial tensile test. This article proposes a design algorithm for the SPRT chart in which the reference value (γ) of the SPRT chart is optimized. The design algorithm increases the overall effectiveness of the SPRT chart by more than 10% on average. Moreover, the improvement in detection effectiveness is achieved without any additional difficulty in implementation. A design table is also provided to facilitate quality engineers to design the SPRT chart. 相似文献
2.
Jiujun Zhang Zhonghua Li Zhaojun Wang 《The International Journal of Advanced Manufacturing Technology》2012,60(9-12):1031-1038
Traditionally, an $\bar{X}$ chart is used to control the process mean, and an R chart is used to control the variance. However, these charts are not sensitive to the small shifts in the processes. The adaptive charts might be considered if the aim is to detect process changes quickly. In this paper, we propose a new adaptive single control chart which integrates the exponentially weighted moving average procedure with the generalized likelihood ratio test statistics for jointly monitoring both the process mean and variability. This new chart is effective in detecting the disturbances that shift the process mean, increase or decrease the process variance, or lead to a combination of both effects. 相似文献
3.
Reza Baradaran Kazemzadeh Mahdi Karbasian Mohammad Ali Babakhani 《The International Journal of Advanced Manufacturing Technology》2013,66(1-4):125-139
This paper proposes a variable sampling interval (VSI) version of the fixed sampling interval (FSI) exponentially weighted moving average (EWMA) t chart developed by Zhang et al. for monitoring the changes in the process mean. An optimal design strategy based on the average time to signal (ATS) is presented. We determine the optimal parameters for the VSI EWMA t chart using a Markov chain approach so that the chart has the desired robustness property against errors in estimating the process standard deviation or changing standard deviation. Also, we explain how the various parameters of this VSI EWMA t chart can be computed and how the use of the VSI feature improves the statistical efficiency of the FSI EWMA t and FSI EWMA X-bar charts in terms of out-of-control ATS performances. Comparisons with the FSI EWMA t and FSI EWMA X-bar charts are performed. 相似文献
4.
Philippe Castagliola Giovanni Celano Sergio Fichera George Nenes 《The International Journal of Advanced Manufacturing Technology》2013,66(9-12):1353-1366
Starting the online monitoring of a quality characteristic by means of a control chart at the beginning of a short production run is often a challenging issue for quality practitioners: in fact, the frequent absence of preliminary information prevents from getting a precise estimate of the characteristic mean and standard deviation. Furthermore, for short runs having a finite rolling horizon, the number of inspections scheduled within the run can be too small to get sufficient samples allowing the phase I implementation of the chart to be completed. Recently, t control charts have been proposed as efficient means to overcome this problem because they do not need any phase I tentative control limits definition or preliminary process knowledge. In this paper, a variable sample size (VSS) version of the t chart is proposed. Adaptive control charts have been implemented with success in long runs: here, the performance of the variable sample size strategy is investigated for a chart used in a short run. The statistical performance of the VSS t chart is compared with the one of the fixed-parameter (FP) t chart for both scenarios of fixed and unknown shift size, with the latter situation being frequent in short-run manufacturing environments. An extensive numerical investigation reveals the potential benefits of the proposed chart. When the statistical design is optimized with respect to a fixed value of the shift size δ, the VSS t chart has a better statistical performance than the FP t chart for moderate to large values of δ. Conversely, for the unknown shift size condition, the VSS t chart always outperforms the FP t chart for in-control average sample sizes ASS0?>?7. An illustrative example shows the implementation of the VSS during the production of a finite lot of mechanical parts. 相似文献
5.
M. Shamsuzzaman Min Xie Thong Ngee Goh Hai Yun Zhang 《The International Journal of Advanced Manufacturing Technology》2009,40(3-4):373-381
This article develops a control chart system consisting of several individual time-between-events (TBE) charts, each of which is used to monitor the time between successive events at different process stages in the manufacturing of a product in a multistage manufacturing system. The design algorithm considers all the TBE charts within a system in an integrative and optimal manner. Numerical studies show that the proposed design algorithm improves the performance characteristics of the chart system significantly and thus the product quality is further guaranteed. The proposed control chart system is easy to understand and operate; thus, the floor operators can utilize and understand it as easily as for the traditional system. 相似文献
6.
Shey-Huei Sheu Shih-Hung Tai 《The International Journal of Advanced Manufacturing Technology》2006,30(5-6):452-458
Most applications of the EWMA control chart for monitoring processes depend on detecting shifts in the process mean. The problem of detecting an increase in process variability, which can also strongly affect the quality of products, is perhaps more important. When a process moves from the pilot phase to the production phase, the mean may not shift but the variation will probably increase because new sources of variation are introduced, including new people and materials. A simulation is performed to evaluate the ARL to false alarm and to monitor the change in the process variability of the EWMA control chart and the GWMA control chart. An extensive comparison reveals that the GWMA control chart is more sensitive than the EWMA control chart in monitoring the variance of a process. The results of this study can be applied to monitor the process variability in automated industries. 相似文献
7.
F.-L. Chen H.-J. Huang 《The International Journal of Advanced Manufacturing Technology》2005,26(7-8):842-851
A synthetic control chart for monitoring the changes in the standard deviation of a normally distributed process is proposed
in this paper. The synthetic chart consists of the sample range (R) chart and the conforming run-length (CRL) chart. The R chart can be viewed as a special case of the synthetic chart. The operation, design and performance of this
chart are described. Average run- length comparisons between other procedures and the synthetic chart are presented. It indicates
that the synthetic chart is a good alternative for monitoring process dispersion. The variable sampling interval (VSI) schemes,
as an enhancement to the synthetic chart, are discussed to further improve the chart performance. An example is presented
to illustrate the application of synthetic chart and its VSI scheme. 相似文献
8.
针对过程均值偏移随机的情况,提出一种统计经济最优的指数加权移动平均控制图优化设计方法。该方法将过程受控、失控未检出、失控被检出并进行恢复这三个阶段定义为一个周期,分析了三个阶段的平均时长及质量成本构成,通过计算产品质量特性超出规格界限的概率量化缺陷产品所造成的质量损失,以单位时间内期望成本最小为目标建立指数加权移动平均控制图优化模型并设计了遗传算法,优化了样本容量、采样间隔、平滑界限和控制界限等参数。通过与休哈特均值控制图、传统指数加权移动平均控制图等进行对比验证了该模型的优越性。 相似文献
9.
薛丽 《计算机集成制造系统》2013,19(6)
为了在提高过程监控效率的同时降低过程监控费用,针对同时监控过程均值和标准差变化的情形,研究可变抽样区间的指数加权移动平均控制图的经济设计问题.首先建立可变抽样区间,同时监控均值标准差指数加权移动平均控制图;其次对其进行经济设计,使单位时间期望费用函数最小,以确定控制图参数的最优值;然后利用遗传算法来寻找经济模型的参数最优解;最后对可变抽样区间同时监控均值标准差指数加权移动平均控制图的经济模型进行灵敏度分析和最优性分析.通过最优性分析得出结论:基于经济模型设计的可变抽样区间指数加权移动平均控制图比传统的控制图具有较小的费用. 相似文献
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12.
Maiko Morita Ikuo Arizono Ippei Nakase Yasuhiko Takemoto 《The International Journal of Advanced Manufacturing Technology》2009,43(3-4):304-311
Process capability indices are widely used to provide the evaluation measure of a process. Especially, the process capability index C pm , which is defined by the range of the process standard specification limits and the deviation from a target value, is called the Taguchi index. Boyles has investigated the statistical characteristics of the estimator $\hat{C}_{pm}$ , and also proposed a technique for the C pm control chart. Since the process capability index C pm is based on the concept of the Taguchi’s quality loss, the process capability index C pm already includes an economical concept. In this article, we evaluate an operating cost consisting of the sampling cost, the sample cost, and the quality loss of failing to detect an out-of-control state when the C pm control chart is used. Then, we derive an optimal operating plan by sample size and sampling interval in order to minimize the ceiling value of the operating cost based on the min–max criterion. 相似文献
13.
Angus Jeang Toly Chen Huan-Chung Li Francois Liang 《The International Journal of Advanced Manufacturing Technology》2007,33(11-12):1159-1172
Conventional process planning of manufacturing operations presets fixed process means and process tolerances for all operations and allows outputs to be distributed around these fixed values, as long as the final outputs meet acceptable specifications. Most of these approaches consider process means and process tolerances to be independent decision variables in process planning with the resultant process means equal or close to the design targets of the blueprint dimensions. Furthermore, these approaches assume that process variability is small in comparison to the quality requirement, and that the phenomena of process shifting or deterioration are not factors of manufacturing operations. For these reasons, conventional approaches to process planning are inappropriate for high value, and precision manufacturing process, particularly of a complex part. Hence, this study introduces a process optimization model which considers process means and process tolerances simultaneously, with sequential operation adjustment to reduce process variability, and with part compensation to offset process shifting. 相似文献
14.
Hovhannes Sadoyan Armen Zakarian Pravansu Mohanty 《The International Journal of Advanced Manufacturing Technology》2006,28(3-4):342-350
In this paper, a new data mining algorithm based on the rough sets theory is presented for manufacturing process control.
The algorithm extracts useful knowledge from large data sets obtained from manufacturing processes and represents this knowledge
using “if/then” decision rules. Application of the data mining algorithm developed in this paper is illustrated with an industrial
example of rapid tool making (RTM). RTM is a technology that adopts rapid prototyping (RP) techniques, such as spray forming,
and applies them to tool and die making. A detailed discussion on how to control the output of the manufacturing process using
the results obtained from the data mining algorithm is also presented. Compared to other data mining methods, such decision
trees and neural networks, the advantage of the proposed approach is its accuracy, computational efficiency, and ease of use. 相似文献
15.
Joint determination of process mean and production run: A review 总被引:1,自引:1,他引:0
K. Tahera W. M. Chan R. N. Ibrahim 《The International Journal of Advanced Manufacturing Technology》2008,39(3-4):388-400
The economic selection of process parameters, mainly process target and production run, is critically important since it directly affects the process defective rate, material cost, scrap or rework cost, and the loss to the customer due to the deviation of the product from specification. One of the goals in process control is to integrate the optimum production run with the optimum process target based on maximising profit or minimising the total cost. This review paper summarises the current research on optimum selection of process mean and production run. The methodologies to solve the parameters of the models are also presented. Some possible future research directions are mentioned in this paper. 相似文献
16.
小批量过程多变异控制图技术研究 总被引:2,自引:1,他引:2
针对小批量过程的主要控制图技术中目标图、比例图和标准变换图,归纳出小批量过程控制的同分布原理。考虑到不同小批量之间的差异,以目标均值控制图为例,对控制图进行改进,给出多变异目标均值控制图的建立步骤。通过一个例子发现,该方法既实现了小批量过程多变异的控制,又降低了控制图虚发警报的概率。 相似文献
17.
Rassoul Noorossana Karim Atashgar Abbas Saghaei 《The International Journal of Advanced Manufacturing Technology》2011,56(5-8):755-765
When an out-of-control condition is detected by a control chart, a search begins to identify and eliminate the source(s) of the signal. Identification of the time when a process first changed is an important step in root cause analysis which helps a process engineer to eliminate the source(s) of assignable cause effectively. The time when a change takes place in the process is referred to as the change point. In multivariate environment, since there is more than one variable involved, then root cause analysis is relatively harder compared to the case of univariate because it is not clear exactly which variable has contributed to the out-of-control condition and in what direction its mean has shifted. Hence, a procedure that identifies the change point, performs diagnostic analysis, and specifies the direction of the shift in the mean of the contributing variable(s) all simultaneously could help to conduct root cause analysis effectively. Although different multivariate methods exist in the literature that allow to either estimate change point in the process mean vector or identify the contributing variables leading to the out-of-control condition, but in this research, an integrated supervised learning solution is proposed, which helps to (1) detect of an out-of-control condition, (2) identify the change point leading to shift in the mean vector, (3) specify the variable(s) contributing to the out-of-condition, and (4) identify the direction of the shift in the mean of each contributing variable simultaneously. A real case study is used to evaluate and compare the performance of the proposed integrated approach to existing methods in the literature. 相似文献
18.
随着集成电路的不断发展,低功耗与小面积逐渐成为芯片设计中的重要指标,促使形成电路的器件尺寸不断降低。在半导体芯片制造过程中,越小的器件尺寸对工艺过程中温度控制的精度要求越高,晶圆温度的轻微偏离和高于1%的温度不均匀性将会直接影响最终产品的良率。为实现温度与温度场分布的高精度控制,需要对其进行更为精确的预先检测与实时获取,集成电路制造中的晶圆温度监测技术应运而生。围绕接触式和非接触式两大测温技术分支,介绍了监测温度范围为0℃~1 300℃的晶圆温度监测技术原理。本文基于原理分析各技术所具有的优势与仍然不能满足的测温技术要求,追踪各测温技术的国内外发展现状,展望了未来晶圆温度监测技术的发展方向。 相似文献
19.
在实际的机电加工生产过程中,产品质量检测过程对整个加工过程以及成品的检测都至关重要.电路板元器件的缺陷检测属于质量控制领域中一项重要研究内容.本文针对基于机器视觉的检测方法,提出了一种多模版匹配的技术来检测具有多个方向的多元器件缺失问题,并将此类问题转化为多峰函数的优化问题,接着对比分析了各种进化算法在求解多峰函数中的不同策略.将Species-GA算法应用在PCB检测过程中,通过与GA-MTM方法进行了对比测试,表明Species-GA在搜索效率上优于GA-MTM. 相似文献
20.
CUSUM管理图(累计和管理图)是面向中小批量生产的最主要的管理图,CUSUM管理图的工序过程在线监控是加工过程工序监控的一种先进技术.本研究首先概括了面向中小批量生产的CUSUM管理图的技术优势和计算模型,然后讨论了JAVA代码CUSUM管理图工序过程在线监控软件的设计,其中详细讨论了时序图和程序框图描述,然后用机床加工的原始数据作了仿真实验.仿真实验结果表明面向中小批量生产的JAVA代码CUSUM管理图的计算模型和工序过程在线监控软件是正确的、有效的和可用的. 相似文献