正確解釋控制圖7大規則
By Mark Durivage, QualitySystems Compliance LLC
Control chartsbuild upon periodic inspections by plotting the process outputs and monitoringthe process for special cause variation or trends. Control charts aredecision-making tools that provide information for timely decisions concerningrecently produced products.‘
控制圖建立在定期檢查的基礎上,繪制過程輸出和監控過程的特殊原因的變化或趨勢??刂茍D是一種決策工具,它為有關最近生產的產品的及時決策提供信息。
Control chartscan be used to identify sources of variation, both common and special cause.Common cause variation is the variation inherent in the process. Common causevariation is also known as the noise of the process. A process with only commoncause variation is highly predictable. A process that has a significantinherent common cause variation may not be capable of producing products thatmeet predetermined specifications. Common cause variation is said to accountfor 80% of the variation in any process and is considered management’sresponsibility.
控制圖可以用來識別變異的來源,包括固有和特殊的原因。固有原因變異是過程中固有的。固有原因變異也被稱為過程噪聲。只有固有原因變異的過程是高度可預測的。具有顯著的固有原因變異的工藝可能不能生產出符合既定標準的產品。固有原因變異占任何過程中80%的變異,并被認為是管理層的責任。
Special cause variationis variation that is not inherent to the process. A process with special causevariation is highly unpredictable. Special cause variation is said to accountfor 20% of the variation in any process and is considered the worker’sresponsibility.
特殊原因變異是指并非該過程固有的變異。具有特殊原因變異的過程是高度不可預測的。特殊原因的變異占任何過程中變異的20%,并被認為是工人的責任。
Control chartscontain a centerline — usually the mathematical average of the samples plotted— and upper and lower statistical control limits that define the constraints ofcommon cause variation and performance data plotted over time.
控制圖包含一條中心線——通常是樣本的數學平均值——以及定義固有原因變化約束的統計控制上、下限和隨時間繪制的性能數據。
There are twogeneral classifications of control charts: variables and attributes charts.Variables are things that can be measured. Attributes are things that can becounted. The type of data (variable or attribute) will dictate the appropriatetype of control chart required to monitor a process. Table 1 can be used forcontrol chart selection.
控制圖一般分為兩類:變量圖(計量型控制圖)和屬性圖(計數型控制圖)。變量是可以測量的東西。屬性是可以計數的東西。數據的類型(變量或屬性)將決定監控過程所需的控制圖的適當類型。表1可用于控制圖的選擇。
Table 1: ControlChart Selection Guide
控制圖選擇指引
Selection of thecorrect type of control chart is important to ensure the underlying statisticalconcepts are appropriate for the feature or attribute being measured.
選擇正確類型的控制圖對于所用的確保底層統計概念適合于待測特征或屬性十分重要。
A process issaid to be in control when the control chart does not indicate anyout-of-control condition and contains only common causes of variation. If thecommon cause variation is small, then a control chart can be used to monitorthe process. If the common cause variation is too large, the process will needto be modified or improved to reduce the amount of inherent variation to anacceptable level.
當控制圖沒有提示任何失控的情況,只包含固有變異原因時,即表示一個過程受控。如果固有原因變異很小,則可以使用控制圖來監控該過程。如果固有原因的變化太大,則需要對該過程進行整改或改進,以將固有變異減少到可接受的水平。
When a controlchart indicates an out-of-control condition (a point outside the control limitsor matching one or more of the criteria in the rules below), the assignablecauses of variation must be identified and eliminated.
當控制圖表明一個失控的情況(一個超出控制限度的點或符合下面規則中的一個或多個標準),必須識別和消除變化的原因。
The followingrules can be used to properly interpret control charts:
以下規則可用于正確解釋控制圖:
Rule 1 – One point beyond the 3 σ control limit
規則1 ——任何1點超出3 σ控制限
Rule 2 – Eight or more points on one side of the centerline without crossing
規則2 ——連續8點或以上在中心線同一側
Rule 3 – Four out of five points in zone B or beyond
規則3 ——連續5點中有4點在B區或B區以上
Rule 4 – Six points or more in a row steadily increasing or decreasing
規則4 ——6個點或更多連續遞增或遞減
Rule 5 – Two out of three points in zone A
規則5 ——連續3點有2點位于A區
Rule 6 – 14 points in a row alternating up and down
規則6 —— 14點在一排交替上下
Rule 7 – Any noticeable/predictable pattern, cycle, or trend
規則7 ——任何明顯的/可預見的模式、周期或趨勢
Analyzing acontrol chart for special cause variation can be facilitated by using thecategories used with a cause-and-effect diagram. The flowing are the categoriesthat I prefer to use:
通過使用與因果圖一起使用的分類,可以方便地分析特殊原因變異的控制圖。以下是我更喜歡使用的類別:
Equipment, Machines, and Tooling
設備、機器和工具
Environment
環境
Process
過程
Inspection
檢查
Materials
物料
Operator
操作人員
Rule 1 – Onepoint beyond the 3 σ control limit
規則1 ——任何1點超出3 σ控制限
Rule 1, onepoint beyond the 3 σ control limits, seeks to identify points that are randomor outliers, as shown here in red. When random or outlier points areidentified, the following are potential special causes to consider:
規則1:任何1點超出3 σ控制限,確定該點是隨機的還是異常值,如圖中紅色所示。當隨機點或離群點被識別時,以下是需要考慮的潛在特殊原因:
Equipment, Machines, and Tooling
設備,機器,和工具
improper start-up
啟動不當
improper setup
設置不當
sudden support system failure (cooling, heating, compressed air, vacuum, steam, etc.)
支持系統(冷卻、加熱、壓縮空氣、真空、蒸汽等)突然故障
tool failure/breakage
工具失效/破損
equipment or machine failure
設備或機器故障
improper equipment, machine, and tooling maintenance
設備、機器和工裝維護不當
utility interruption
公用系統中斷
Environment
設備
temperature suddenly too low/high
溫度突然太低/太高
humidity suddenly too low/high
濕度突然太低/太高
Process
過程
equipment has not stabilized (warmed-up)
設備未穩定(預熱)
inadequate work instructions
不適當的工作指令
missed process step
工藝步驟缺失
new process
新的工藝
Inspection
檢查
inspection, measuring, and testing equipment not properly calibrated
檢查、測量和測試設備未正確校準
damaged inspection, measuring, and testing equipment
檢查、測量和測試設備損壞
Materials
物料
change in raw materials
原料變更
change in components
組件變更
handling damage
處理失效
expired materials
物料超有效期
Operator
操作人員
new operators
新的操作人員
inadequate training
培訓不足
operator interrupted or distracted
操作人員中斷或分心
operator overcompensating when making process adjustments
操作人員在進行過程調整時過度補償
Rule 2 – Eightor more points on one side of the centerline without crossing
規則2 ——連續8點或以上在中心線同一側
Rule 2, eight ormore points on one side of the centerline without crossing, is considered aprominent shift (the shift can be on either side of the centerline). The pointscircled in red are considered a prominent shift. When a prominent shift isidentified, the following are potential special causes to consider:
規則2:連續8點或以上在中心線同一側,被認為是明顯的移位(這種移位可以在中心線的任何一側)。如圖,紅圈中的點被認為是一個顯著的移位。當發現一個顯著的移位時,以下是需要考慮的潛在特殊原因:
Equipment, Machines, and Tooling
設備,機器,和工具
improper setup
設置不當
improper equipment, machine, and tooling maintenance
設備,機器,和工具維護不當
damaged tooling
工具損壞
tool wear
工具磨損
Environment
環境
temperature shifted too low/high
溫度變化過低/過高
humidity shifted too low/high
濕度變化過低/過高
Process
過程
new process parameters
新的工藝參數
incorrect process parameters
不正確的工藝參數
process has improved
工藝改善
process has degraded
工藝退化
Inspection
檢查
inspection, measuring, and testing equipment not properly calibrated
檢查,測量,和測試設備校準不當
damaged inspection, measuring, and testing equipment
檢查,測量,和測試設備損壞
Materials
物料
change in raw materials
原料變更
change in components
組件變更
expired materials
物料過期
Operator
操作人員
new operators
新的操作人員
inadequate training
培訓不充分
operator interrupted or distracted
操作人員中斷或分心
shift change
班次變更
Rule 3 – Fourout of five points in zone B or beyond
規則3 ——5點有4點在B區或B區以上
Rule 3, four outof five points in zone B or beyond, is considered a small shift (the shift canbe on either side of the centerline). The points circled in red are consideredsmall shifts. When a small shift is identified, the following are potentialspecial causes to consider:
規則三:5點有4點在B區或B區以上,被認為是一個小的波動(這個波動可以在中心線的任何一邊)。如圖,紅圈中的點被認為是小波動。當發現微小的波動時,以下是需要考慮的潛在特殊原因:
Equipment, Machines, and Tooling
設備,機器,和工具
improper setup
設置不當
intermittent support system failure (cooling, heating, compressed air, vacuum, steam, etc.)
支持系統(冷卻、加熱、壓縮空氣、真空、蒸汽等)間歇故障
improper equipment, machine, and tooling maintenance
設備,機器,和工具維護不當
Environment
設備
temperature suddenly too low/high
溫度突然太低/太高
humidity suddenly too low/high
濕度突然太低/太高
Process
工藝
new process parameters
新的工藝參數
incorrect process parameters
不正確的工藝參數
process has improved
工藝改進
process has degraded
工藝退化
Inspection
檢查
inspection, measuring, and testing equipment not properly calibrated
檢查,測量,和測試設備校準不當
inspection, measuring, and testing equipment not adequate for the intended use
檢查,測量和測試設備不適合其預定用途
damaged inspection, measuring, and testing equipment
檢查,測量和測試設備損壞
Materials
物料
mixed raw materials
原料混淆
mixed components
組件混淆
Operator
操作人員
new operators
新的操作人員
inadequate training
培訓不充分
operator interrupted or distracted
操作人員中斷或分心
shift change
班次變化
Rule 4 – Sixpoints or more in a row steadily increasing or decreasing
規則4 ——6個或以上的點連續遞增或遞減
Rule 4, sixpoints or more in a row steadily increasing or decreasing, is considered atrend (the trend can be rising or falling). The points circled in red areconsidered a trend. When a trend is identified, the following are potentialspecial causes to consider:
規則4:6個或以上的點連續遞增或遞減,被認為是一種趨勢(趨勢可以上升或下降)。紅圈中的點被認為是一種趨勢。當確定一種趨勢時,以下是需要考慮的潛在特殊原因:
Equipment, Machines, and Tooling
設備,機器和工具
gradual support system failure (cooling, heating, compressed air, vacuum, steam, etc.)
支持系統(冷卻、加熱、壓縮空氣、真空、蒸汽等)逐漸失效
tool wear
工具磨損
Environment
環境
temperature gradually drifting too low/high
溫度逐漸降低/升高
humidity gradually drifting too low/high
濕度逐漸降低/升高
Process
工藝
process is slowly degrading
工藝正在逐漸退化
Inspection
檢查
inspection, measuring, and testing equipment not adequate for the intended use
檢查,測量,和測試設備不適合其預定用途
damaged inspection, measuring, and testing equipment
檢查,測量,和測試設備損壞
Materials
物料
variation in the raw materials
原料變化
variation in the components
組件變化
Operator
操作人員
operator distracted
操作人員分心
Rule 5 – Two outof three points in zone A
規則5 —— 3點有2點在A區
Rule 5, two outof three points in zone A, is considered a large shift. (the shift can be oneither side of the centerline). The points circled in red are considered largeshifts. When a large shift is identified, the following are potential specialcauses to consider:
規則5:3點有2點位于A區,被認為是一個大的變異。(變異可以在中心線的任何一邊)。如圖,紅圈里點被認為是大變異。當發現一個大的變異時,以下是需要考慮的潛在特殊原因:
Equipment, Machines, and Tooling
設備,機器,和工具
improper setup
設置不當
support system failure (cooling, heating, compressed air, vacuum, steam, etc.)
支持系統(冷卻、加熱、壓縮空氣、真空、蒸汽等)故障
improper equipment, machine, and tooling maintenance
設備、機器和工具維護不當
Environment
環境
temperature suddenly too low/high
溫度突然過低/過高
humidity suddenly too low/high
濕度突然過低/過高
Process
工藝
new process parameters
新的工藝參數
incorrect process parameters
不正確的工藝參數
process has degraded
工藝退化
Inspection
檢查
inspection, measuring, and testing equipment not properly calibrated
檢查,測量,和測試設備校準不當
inspection, measuring, and testing equipment not adequate for the intended use
檢查,測量,和測試設備不適合其預定用途
damaged inspection, measuring, and testing equipment
檢查,策略,和測試設備損壞
Materials
物料
mixed raw materials
原料混淆
mixed components
組分混淆
Operator
操作人員
new operators
新的操作人員
inadequate training
培訓不充分
operator interrupted or distracted
操作人員中斷或分心
shift change
班次變化
Rule 6 – 14points in a row alternating up and down
規則6——連續14點在同一側交替上下
Rule 6, 14points in a row alternating up and down, is generally considered to be overcontrol.The points enclosed in red are considered out of control. When this situationis identified, the following are potential special causes to consider:
規則6:連續14點在同一側交替上下,通常被認為是控制過度。如圖,紅圈中的點被認為是失控的。當發現這種情況時,以下是需要考慮的潛在特殊原因:
Equipment, Machines, and Tooling
設備,機器,和工具
improper setup
設置不當
intermittent support system failure (cooling, heating, compressed air, vacuum, steam, etc.)
支持系統(冷卻、加熱、壓縮空氣、真空、蒸汽等)間歇故障
improper equipment, machine, and tooling maintenance
設備、機器和工具維護不當
Environment
環境
temperature intermittently too low/high
溫度間歇性過低/過高
humidity intermittently too low/high
濕度間歇性過低/過高
Process
工藝
equipment has not stabilized (warmed-up)
設備未穩定(預熱)
new process parameters
新的工藝參數
incorrect process parameters
不正確的工藝參數
inadequate work instructions
不適當的工作指令
missed process step
工藝步驟缺失
new process
新的工藝
Inspection
檢查
inspection, measuring, and testing equipment not adequate for the intended use
檢查,測量,和測試設備不適合預期用途
damaged inspection, measuring, and testing equipment
檢查,測量,和測試設備損壞
Materials
物料
mixed raw materials
原料混淆
mixed components
組分混淆
Operator
操作人員
new operators
新的操作人員
inadequate training
培訓不當
operator overcompensating when making process adjustments
操作員在進行工藝調整時過度補償
operator not waiting for the process to stabilize before making process adjustments
操作人員未等待工藝穩定后再進行工藝調整
Please note,even though the operator may be over adjusting the process, there may be otherspecial causes present.
請注意,即使操作人員調整過程過度,也可能有其他特殊原因。
Rule 7 – Anynoticeable/predictable pattern, cycle, or trend
規則7 -任何顯著的/可預見的模式、周期或趨勢
Rule 7 is anynoticeable/predictable pattern, cycle, or trend. The points circled in red areconsidered out of control. When these situations are identified, the followingare potential special causes to consider:
規則7:任何顯著的/可預測的模式、周期或趨勢。如圖,紅圈中的點被認為是失控的。當發現這些情況時,以下是需要考慮的潛在特殊原因:
Equipment, Machines, and Tooling
設備,機器,和工具
improper setup
設置不當
intermittent support system failure (cooling, heating, compressed air, vacuum, steam, etc.)
支持系統(冷卻、加熱、壓縮空氣、真空、蒸汽等)間歇性故障
gradual support system failure (cooling, heating, compressed air, vacuum, steam, etc.)
支持系統(冷卻、加熱、壓縮空氣、真空、蒸汽等)逐漸故障
improper equipment, machine, and tooling maintenance
設備、機器和工具維護不當
tool wear
工具磨損
Environment
設備
temperature gradually drifting too low/high
溫度逐漸升高/降低
humidity gradually drifting too low/high
濕度逐漸升高/降低
temperature shifted too low/high
溫度變化過低/過高
humidity shifted too low/high
濕度變化過低/過高
temperature intermittently too low/high
溫度間歇性過低/過高
humidity intermittently too low/high
濕度間歇性過低/過高
Process
工藝
equipment has not stabilized (warmed-up)
設備未穩定(預熱)
new process parameters
新的工藝參數
incorrect process parameters
不正確的工藝參數
inadequate work instructions
不適當的工作指令
missed process step
工藝步驟確實
new process
新的工藝
two or more processes
該過程實際上是兩個或以上的過程糅合
Inspection
檢查
inspection, measuring, and testing equipment not properly calibrated
檢查,測量,和測試設備未適當校準
inspection, measuring, and testing equipment not adequate for the intended use
檢查,測量,和測試設備不適合其預定用途
damaged inspection, measuring, and testing equipment
檢查,測量,和測試設備損壞
Materials
物料
change in raw materials
原料變更
change in components
組件變更
mixed raw materials
原料混淆
mixed components
組件混淆
variation in the raw materials
原料變化
variation in the components
組件變化
Operator
操作人員
new operators
新的操作人員
inadequate training
培訓不當
operator interrupted or distracted
操作人員中斷或分心
multiple shifts
多個班組
Stratification
分段
Whenstratification is identified, it is generally due to one of two issues. Theoperators are purposefully truncating the measurements, or the process hasimproved significantly, which will require the recalculation of the statisticalcontrol limits.
當確定分段時,通常是由于兩個問題之一。操作人員有意截斷測量,或者工藝有了明顯改進,需要重新計算統計控制限。
Conclusion
結論
It is time toconsider augmenting your validated pharmaceutical, medical device, and tissueproduction processes, including processing, packaging, and labeling, withcontinuous process monitoring using control charts to ensure continuedcompliance with established specifications and requirements.
是時候考慮加強你們已驗證的制藥、醫療器械和生產工藝,包括加工、包裝和貼標,使用控制圖進行持續工藝監控,以確保持續符合既定的標準和要求。
When implementingcontrol charts as part of your continuous process monitoring activities, ensurethe people responsible for completing the charts have been properly trained andunderstand the seven rules presented in this article.
在實現控制圖作為持續過程監控活動的一部分時,確保負責完成這些圖的人員得到了適當的培訓,并理解了本文中提出的7大規則。
I cannotemphasize enough the importance of establishing documented procedures to managethe tools and methods used. Best practice includes providing the rationale foryour organization’s use of control charts for continuous process monitoring.The methods and tools presented in this article can and should be utilizedbased upon industry practice, guidance documents, and regulatory requirements.
建立書面的程序來管理所使用的工具和方法的重要性再怎么強調也不為過。最佳實踐包括為公司使用控制圖進行連續過程監控提供論據。本文提供的方法和工具可以并且應該根據行業實踐、指導文件和法規要求加以利用。