FMEA和FMECA的基本概念综述

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AS9100C版中提出了FMEA和FMECA，以下参考文章可能有参考价值

Failure Modes and Effects Analysis (FMEA) and Failure Modes, Effects and Criticality Analysis (FMECA)
An Overview of Basic Concepts
失效模式和后果分析和失效模式、后果和临界度分析的基本概念综述

Failure Mode and Effects Analysis (FMEA) and Failure Modes, Effects and Criticality Analysis (FMECA) are methodologies designed to identify potential failure modes for a product or process, to assess the risk associated with those failure modes, to rank the issues in terms of importance and to identify and carry out corrective actions to address the most serious concerns.
失效模式和后果分析（FMEA）和失效模式、后果和临界度分析（FMECA）是设计用来识别某一产品或过程潜在的失效模式，然后，评估由于这些失效引起的有关后果，再按照问题的重要程度加以排队，针对问题的原因，采取各种纠正措施，用这样的方法来描述最最严重的需要加以关注的问题的各种方法。

Although the purpose, terminology and other details can vary according to type (e.g. Process FMEA - PFMEA, Design FMEA - DFMEA, System FMEA, Product FMEA, FMECA, etc.), the basic methodology is similar for all. This document presents a brief general overview of FMEA / FMECA analysis techniques and requirements.
尽管它么的叫法有很多种，目的也不同，因此有各种类型（也就是过程失效模式和后果分析-PFMEA、设计失效模式和后果分析-DFMEA、系统失效模式和后果分析- SFMEA、产品失效模式和后果分析、失效模式、后果和临界度分析-FMECA等等），它们的基本方法是相似的。本文简要描述一下如何做 FMEA / FMECA，以及做的时候的要求。

FMEA / FMECA Overview FMEA / FMECA综述

In general, Failure Modes, Effects and Criticality Analysis (FMEA / FMECA) requires the identification of the following basic information:
总的来说，FMEA / FMECA要求识别以下的基本信息：

Item(s) 实体（译者注：也就是做FMEA / FMECA要分析的对象，譬如某一个产品、过程、系统等）
Function(s) 功能（以上这个实体的功能）
Failure(s) 失效
Effect(s) of Failure 失效以后引起的后果
Cause(s) of Failure 失效的原因
Current Control(s) 现在采用什么控制方式方法
Recommended Action(s)  建议采取措施
Plus other relevant details 再有其他有关的详细信息

Most analyses of this type also include some method to assess the risk associated with the issues identified during the analysis and to prioritize corrective actions. Two common methods include:
这些分析方法中大多包括一些用来评估和这些问题有联系的风险，然后排出优先采取纠正措施的次序。通常采用的方法包括：

Risk Priority Numbers (RPNs) 风险序数

Criticality Analysis (FMEA with Criticality Analysis = FMECA) 临界度分析（当FMEA加上临界度分析就变成FMECA)
Published Standards and Guidelines采用已经出版的标准和指导文件

There are a number of published guidelines and standards for the requirements and recommended reporting format of failure mode and effects analyses. Some of the main published standards for this type of analysis include SAE J1739, AIAG FMEA-3 and MIL-STD-1629A. In addition, many industries and companies have developed their own procedures to meet the specific requirements of their products/processes. Figure 1 shows a sample Process FMEA (PFMEA) in the Automotive Industry Action Group (AIAG) FMEA-3 format. Click to enlarge the image.
已经颁布了一些指导如何做失效模式和后果分析的要求和建议采用的报告表格。其中主要的有SAE J1739, AIAG FMEA-3 and MIL-STD-1629A。另外，很多行业和公司也已经针对他们的产品/过程，开发了他们自己的程序，以便满足他们特定的各种要求。图1给出汽车行业AIAG过程的FMEA（也就是PFMEA）所采用的格式FMEA-3 。请看原帖子。可以点击后放大的。
Figure 1      [Enlarge]

Basic Analysis Procedure for FMEA or FMECA做FMEA或 FMECA的基本程序

The basic steps for performing an Failure Mode and Effects Analysis (FMEA) or Failure Modes, Effects and Criticality Analysis (FMECA) include:

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基本步骤包括：

Assemble the team. 建立分析团队
Establish the ground rules. 建立基本的规则
Gather and review relevant information. 收集和评审有关的信息
Identify the item(s) or process(es) to be analyzed. 识别需要加以分析的实体或者过程
Identify the function(s), failure(s), effect(s), cause(s) and control(s) for each item or process to be analyzed.针对没个需要加以分析的实体或者过程识别功能、失效模式、后果、原因、和现在采用的控制方式方法
Evaluate the risk associated with the issues identified by the analysis.  评估通过分析确定问题有关的风险
Prioritize and assign corrective actions.  给以上确定风险排队，然后提出纠正措施
Perform corrective actions and re-evaluate risk.  执行纠正措施，然后，再评估风险
Distribute, review and update the analysis, as appropriate.  把报告分发给有关人员，加以评审，如果需要的话，再分析

Risk Evaluation Methods 风险评估的各种方法

A typical failure modes and effects analysis incorporates some method to evaluate the risk associated with the potential problems identified through the analysis. The two most common methods, Risk Priority Numbers and Criticality Analysis, are described next.
典型的失效模式后果分析总会包括某些评估方法，用这些方法来评估通过分析识别确定各种潜在问题有关的风险。最常用的两种方法是风险序数和临界度分析。下面加以解释。

Risk Priority Numbers风险序数