關(guān)于特殊特性kpc、kcc的理解(編輯修改稿)
2025-07-15 15:09 本頁(yè)面
【文章內(nèi)容簡(jiǎn)介】 Ppk in QS9000 means Preliminary Process Capability Index. It should be calculated before Mass Production and based on limited product quantity. Normally, it should be more than because it39。s a short term process capability which doesn39。t consider the long term variation. But, in QS9000 3rd edition, there39。s no Compulsory Requirement that the Ppk must be more than . In QS9000 3rd edition, it states like Ppk/Cpk =.Another one is in 6Sigma. Ppk in 6Sigma means Process Performance Index. It39。s a long term process capability covered the long term process variation and based on more product quantity. Generally, in 6Sigma, the Ppk value is less than Cpk value.Ppk：Overall performance capability of a process, see 。Cp：A widely used capability index for process capability studies. It may range in value from zero to infinity with a larger value indicating a more capable process. Six Sigma represents Cp of . 在流程能力分析方面被廣泛應(yīng)用的能力指數(shù)，在數(shù)值方面它可能是從零到顯示更強(qiáng)有力流程的無(wú)窮大之間的某個(gè)點(diǎn)。六個(gè)西格瑪代表的是Cp=。 Cpk：A process capability index bining Cp and k (difference between the process mean and the specification mean) to determine whether the process will produce units within tolerance. Cpk is always less than or equal to （表示流程平均值與上下限區(qū)間平均值之間的差異）結(jié)合起來(lái)的流程能力指數(shù)，它用來(lái)確定流程是否將在容忍度范圍內(nèi)生產(chǎn)產(chǎn)品，Cpk通常要么比Cp值小，要么與Cp值相同?！痹谝话愕腝S9000或TS16949推行過(guò)程中，Ppk用來(lái)表示短期能力指數(shù)，Cpk用來(lái)表示長(zhǎng)期能力指數(shù)。但是受知識(shí)所限，我本人沒(méi)有看到這方面的權(quán)威資料。這位網(wǎng)友的帖子上面也表達(dá)了兩種不同的觀點(diǎn)，而且這兩種觀點(diǎn)近乎對(duì)立。我本人認(rèn)為，從Ppk的計(jì)算公式中使用的 分析，Ppk表達(dá)的應(yīng)該是一個(gè)包含引起變差的普通原因和特殊原因的過(guò)程。這樣的過(guò)程其實(shí)就是一個(gè)非受控過(guò)程，而一個(gè)非受控過(guò)程在理論上應(yīng)該是在過(guò)程初期和長(zhǎng)期過(guò)程中都會(huì)遇到的。、,采用連續(xù)抽樣。 玫兒 發(fā)表于 2010325 06:24說(shuō)說(shuō)我見過(guò)的資料敘述，涉及到子組的當(dāng)然要塊壯間隔抽樣，就是組內(nèi)連續(xù)，組間隔開，減少異常干擾。關(guān)于標(biāo)準(zhǔn)差的取值，CPK，PPK的區(qū)別在于一個(gè)除n，一個(gè)除n1.CPK的標(biāo)準(zhǔn)差是控制圖的估算標(biāo)準(zhǔn)差的根號(hào)N倍。高人覺(jué)得是否是這樣？ 彎月看海 發(fā)表于 2010325 10:18wh831106和hansenyi說(shuō)的都對(duì)。LZ解惑否？ 泡泡魚 發(fā)表于 2010325 14:13CPK與PPK區(qū)別： CPK的標(biāo)準(zhǔn)差是估算出來(lái)的（查表）；取樣通常是分組式（組內(nèi)是連續(xù)的，組與組之間是間隔的。） PPK的標(biāo)準(zhǔn)差是算出來(lái)的；通常取樣是連續(xù)的。CMK：是設(shè)備能力指數(shù) wlhong 發(fā)表于 2010325 18:07Cpk,
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