• 제목/요약/키워드: PM Capability

검색결과 207건 처리시간 0.029초

Proposal of a New Process Capability Index Based on Dollar Loss by Defects

  • Park, Seung-Wook
    • International Journal of Quality Innovation
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    • 제9권1호
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    • pp.41-54
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    • 2008
  • The process capability indices have been widely used to measure process capability and performance. In this paper, we proposed a new process capability index which is based on an actual dollar loss by defects. The new index is similar to the Taguchi's loss function and fully incorporates the distribution of quality attribute in a process. The strength of the index is to apply itself to non-normal or asymmetric distributions. Numerical examples were presented to show superiority of the new index against $C_p$, $C_{pk}$, and $C_{pm}$ which are the most widely used process capability indices.

다구찌의 손실함수(損失函數)를 이용한 공정능력지수(工程能力指數)의 최적화(最適化)에 관한 연구(硏究) (Optimization of Process Capability Index by Loss Function of Taguchi)

  • 구본철;송단일
    • 품질경영학회지
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    • 제20권1호
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    • pp.80-90
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    • 1992
  • In industries, the capability indices $C_p$ and $C_{pk}$ can be used to provide measures of process potential capability and performance, respectively. The new approach advocated by Taguchi in quality control overcomes some problems in other approaches preventive management activities. Taguchi introduces the emphasis on loss function to improve quality of products on the side of customer. The proceeding concept of capability indices is not rational for the measurement of quality if the process mean is not equal to target value. The Taguchi approach is said to be more reasonable than the others in quality evaluation because of his loss function. However, the capability indices $C_{pm}{^+}$ and $C_{pn}$ using Taguchi's loss function only consider, acceptance cost for deviation from target value within specification limits. In other words, they do not include rejection cost for nonconformings that are failed to fall on the specification limits.

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다특성을 고려한 상황하에서의 공정능력지수에 관한 연구 (A Study on Process Capability Index using Loss Function Under the Muli-Attribute Conditions)

  • 김연희;김수열;박명규
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2005년도 춘계학술대회
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    • pp.503-521
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    • 2005
  • Process capability indices are widely used in industries and quality assurance system. When designing the parameter on the multiple quality characteristics, there has been a study for optimization of problems, but there has been few former study on the possible conflicting phenomena in considertion of the correlations among the characteristics. To solve the issue on the optimal design for muliple quality characteristics, the study propose the expected loss function with cross-product terms among the characteristics and derived range of the coefficients of terms. Therefore, the analysis have to be required a multivariate statistical technique. This paper introduces to multivariate capability indices and then selects a multivariate process capability index incorporated both the process variation and the process deviation from target among these indices under the multivariate normal distribution. We propose a new multivariate capability index $MC_{pm}^{++}$ using quality loss function instead of the process variation and this index is compared with the proposed indices when quality characteristics are independent and dependent of each other,

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기대손실함수를 이용한 다특성치 공정능력지수에 관한 연구 (A Study on Multiple Characteristics Process Capability Index using Expected Loss Function)

  • 김수열;조용욱;박명규
    • 대한안전경영과학회:학술대회논문집
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    • 대한안전경영과학회 2004년도 추계학술대회
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    • pp.69-79
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    • 2004
  • Process capability indices are widely used in industries and quality assurance system. When designing the parameter on the multiple quality characteristics, there has been a study for optimization of problems, but there has been few former study on the possible conflicting phenomena in considertion of the correlations among the characteristics. To solve the issue on the optimal design for multiple quality characteristics, the study propose the expected loss function with cross-product terms among the characteristics and derived range of the coefficients of terms. Therefore, the analysis have to be required a multivariate statistical technique. This paper introduces to multivariate capability indices and then selects a multivariate process capability index incorporated both the process variation and the process deviation from target among these indices under the multivariate normal distribution. We propose a new multivariate capability index $MC_{pm}^{++}$ using quality loss function instead of the process variation and this index is compared with the proposed indices when quality characteristics are independent and dependent of each other.

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Complex Shaped PM-parts by Warm Flow Compaction Process

  • Veltl, Georg;Petzoldt, Frank
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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    • pp.203-204
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    • 2006
  • There is an increasing demand for PM-processes with the capability to produce parts of higher complexity than with conventional press and sinter technology in high production numbers. Warm-flow-compaction (WFC) makes use of improved flowability of powders when blended in an appropriate ratio with fine powder fractions and lubricating binders. Here the process is shown with examples of PM-Steels. General features possible with the process like pressing of undercuts and threaded bores are shown.

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일개 도시 취약 가족의 특성에 관한 조사연구 (A Survey on the Characteristics of Vulnerable Families in a City)

  • 최경원;이인숙
    • 지역사회간호학회지
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    • 제20권3호
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    • pp.371-380
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    • 2009
  • Purpose: This study aimed at describing the characteristics and nursing needs of vulnerable families in a City. Methods: A total of 427 vulnerable families enrolled in the Visiting Health Care Center in K-gu of S city were investigated in this study. Data were collected using questionnaires for one year from Jan to Dec, 2003, and analysed using mean, standard deviation and $x^2$. Results: Most of the vulnerable families investigated here showed many deficits, especially incomplete family structure (62.8%), financial problem (84.0%), lack of support (55.8%) were prevalent. The score of level of economic status in Family Capability for Self management ($1.95{\pm}0.65$) was lowest, and the score of perception of family problem and health of family members ($2.62{\pm}0.78$) was highest. The four family groups divided according to the total score of family management capability showed significant differences in family interaction, support, and coping domain. The total score of family management capability increased as family functioning-related problems decreased in the vulnerable families. Conclusion: In order to find vulnerable families, and improve their family function, it is required to develop the systematic assesment tools, community supportive systems and nursing interventions for family strength.

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공정능력지수들과 6 시그마 품질수준에 대한 통계적 추론 (Statistical Inference for Process Capability Indices and 6 Sigma Qualify Levels)

  • 조중재;심규영;박병선
    • Communications for Statistical Applications and Methods
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    • 제15권3호
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    • pp.451-464
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    • 2008
  • 6 시그마는 백만 기회당 3.4개의 결점만을 갖는 최고의 품질수준을 의미한다. 일반적으로 높은 시그마 품질수준은 고객들에게 높은 만족도를 부여하는 것으로 알려져 있다. 공정능력지수들과 시그마 품질수준 $Z_{st}$는 6시그마 산업에서 공정능력을 평가하기 위하여 널리 이용되고 있다 공정능력지수에 관한 대부분의 평가들은 공정능력분석에 대해 경우에 따라 믿기 어려운 상황을 초래할 수도 있는 점 추정에 초점을 두고 있다. 본 논문에서는 현장 실무자들이 공정능력 여부를 결정하기 위하여 사용하고 있는 6시그마 품질수준 $Z_{st}$와 공정능력지수들 $C_p$, $C_{pk}$$C_{pm}$에 대하여 몇 가지 통계적 추정문제를 기초로 보다 효율적인 검정 방법에 대하여 제안, 연구하였다. 제안된 붓스트랩 검정 방법에 근거한 모의실험 결과는 공정분포의 정규성 여부에 관계없이 그리고 복잡한 계산 과정 없이 보다 효율적으로 적용될 수 있음을 입증하고 있다.

공정능력지수에 대한 붓스트랩과 모의실험연구 (Bootstrapping Some Process Capability Indices)

  • 김평구;조중재
    • 품질경영학회지
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    • 제23권4호
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    • pp.157-166
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    • 1995
  • Process capability indices are used to determine whether a production process is capable of producing items within a specified tolerance. We could estimate the finite sample distributions of some process capability indices with bootstrap method. In this paper, we derive the asymptotic bootstrap distributions of some process capability indices ${\hat{C}}^*_p$, ${\hat{C}}^*_{pk}$ and ${\hat{C}}^*_{pm}$ under general proper conditions. These asymptotic distributiops would be used in constructing some bootstrap confidence intervals. Also, we examine some small sample properties related to these estimators by some simulations.

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Bootstrapping Unified Process Capability Index

  • Cho, Joong-Jae;Han, Jeong-Hye;Jo, See-Heyon
    • Journal of the Korean Statistical Society
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    • 제26권4호
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    • pp.543-554
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    • 1997
  • A family of some capability indices { $C_{p}$(.alpha.,.beta.); .alpha..geq.0, .beta..geq.0}, containing the indices $C_{p}$, $C_{{pk}}$, $C_{{pm}}$, and $C_{{pmk}}$, has been defined by Vannman(1993) for the case of two-sided specification interval. By varying the parameters of the family various capability indices with suitable properties are obtained. We derive tha asymptotic distribution of the family { $C_{p}$(.alpha.,.beta.); .alpha..geq.0,.beta..geq.0} under general proper conditions. It is also shown that the bootstrap approximation to the distribution of the estimator $C_{p}$(.alpha., .beta.) is vaild for almost all sample sequences. These asymptotic distributions would be used in constructing some bootstrap confidence intervals.tervals.

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시스템 공정능력지수의 특성분석 (Characteristic Analysis of the System Process Capability Indices)

  • 이도경
    • 산업경영시스템학회지
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    • 제38권1호
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    • pp.182-187
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    • 2015
  • Process capability indices (PCIs) have been widely used in manufacturing industries to provide a quantitative measure of process potential and performance to meet the specification limits on quality characteristics. The most of existing PCIs are concerned with a single variable. But, in many cases, people want to express a integrated PCI which includes a couple of sequential processes. In this paper, we analyzed the characteristics of system PCIs such as ${\bar{Cp}}(f)$, $SC_{pk}$, $SC_{psk}$, $C^T_{psk}(m)$ and $SC_{pm}(m)$.