FPY與RTY的含義與區別，為什么RTY比FPY更適合？

FPY（First Pass Yield） 與 RTY（Roll ThroughPut Yield）

為什么RTY比FPY更適合?

作為過程質量的衡量標準，效益是6西格瑪的重要前提。 有兩種類型的效益計算方式：第一次通過率或FPY和滾動產量產量或RTY。? 本文比較滾動通過率與第一次通過率。 并解釋了如何根據六西格瑪方法計算方法。

我們通過如下及部分進行學習：

• yield的含義及定義
• First-pass yield or Throughput yield (FPY)
• 圖解– FPY
• Rolled-throughput Yield (RTY)
• RTY – 公式及圖解?(方法 1)
• RTY – 公式及圖解(方法 2)

Yield在精益生產中的定義

收益是精益生產中的一項關鍵指標。 精益生產中的Yield或FPY或RTY僅僅是產生的良品與總加工數量的比率。 以下是“unit”一詞的解釋。unit可以是正在進行的任何項目。

兩種類型的Yield

First-pass yield (FPY)

有不同的方法來定義收益率，或者您也可以將其稱為收益率類型。第一個是第一次通過率，縮寫為FPY。它也是已知的第一次產量或產率。這是一個基于單位的指標。第一次產量的缺點是它忽略或不考慮帶有一個或多個缺陷的廢品的任何返工。在這種情況下，在進行任何“檢查”以確定單元是否良好之后進行計算。

讓我們看一下第一次產量或吞吐量產量公式的說明。我們正在尋找BPO公司的電子郵件回復流程，該公司作為公用事業和能源公司的服務提供商。我們正在查看電子郵件的數量，即550;這是由一組客戶服務人員回應的。在將這些電子郵件發送給客戶之前，所有這些電子郵件都經過了檢查或質量檢查。在質量審核期間，發現203封電子郵件攜帶大量錯誤或缺陷。作為糾正練習的一部分，在203封電子郵件中，190個被重新編寫并發送回電子郵件處理隊列。此外，13封電子郵件的回復非常糟糕，根本無法發送給客戶。

因此;該過程的第一次產量或吞吐量產量公式將為347除以550.這給出了0.630或63.09％。我們是怎么到達347的？這是550（電子郵件總數）減去203（缺陷）的結果。當我們想要計算最終發送給客戶的電子郵件數量時，我們會從電子郵件總數中減去缺陷數量（13）。

Rolled-throughput Yield (RTY)

現在讓我們討論滾動產量的概念。 首字母縮略詞是RTY。 RTY意味著什么？ RTY是衡量整體過程質量水平的指標。 它通過將每個過程步驟的DPMO相乘來總結過程或產品的DPMO數據。滾動產量收率是首過率產量的首選收率計算方法。

RTY小于任何單個過程的最低產量。 每個流程步驟始終具有最小和最大產量。 隨著處理步驟數量的增加，RTY指數變小。

現在讓我們看一下RTY的例子。 我們將討論兩個計算RTY的公式。 我們來看看第一個。

Illustrations of RTY

First method to calculate RTY

We’ve got 5 process steps in this example. Each step has got input units and output units.?Input units are the ones entering each process step, and output units refer to good units produced by each process step.?With the help of a formula, we’ve got the first pass yield for each process step. To calculate RTY, multiply the FPY of each process steps to get the answer. In this case, your equation will be the multiplication of five FPY values which will result in 0.6372. In other words, your RTY for all process steps is 63.72%. That was the first throughput yield formula.

Second method to calculate RTY

Let us have a look at the second method of RTY calculation. We’ve again got 5 process steps in this example. To use this method; you need to have two metrics i.e. DPMO and DPU calculated for each process step.

We will now review the calculations to determine the DPU and?DPMO.

Calculation of DPU

• Determine the number of units
• Count the number of defects
• Divide the number of defects by the number of units

Calculation of DPMO

• Determine the number of units
• Determine the number of defect opportunities per unit
• Determine the total number of defect opportunities for all the units by multiplying the number of defects per opportunity by the total number of units
• Count the units with defects in the total sample by counting how many opportunities within the sample group contained defects or errors
• Divide the total defects by the total opportunities and multiply by a million

Another simple way to calculate DPU

In this example, we’ve calculated DPU using another quick formula. We’ve divided DPMO figure by 1 million to get DPU for each process step. Why did we do that? DPMO incorporates 1 million defect opportunities, and we need to know defect opportunities for each unit. That is why we divided DPMO by 1 million.

Calculating the RTY from the DPU

In the next column, we have deducted DPU from 1 to get the first-pass yield (FTY) for each process step. The 1 refers to 100%. The logic here is simple. The 100% yield for each process step minus defect opportunities per-unit for each process step is equivalent to good units produced by each process step. In this method,?the RTY is calculated by multiplying the FTY for each process as determined in the previous step to get the RTY.

RTY is a realistic view of the yield of any process, looking at all the process steps.?The RTY of a process is a good measure of the quality of a process.?If the RTY is too low, then a problem-solving team needs to investigate how the process can be improved.