第七篇——FMEA Can Add Value in Various Project Stages

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FMEA Can Add Value in Various Project Stages
FMEA 能在项目的不同阶段带来附加值

Although it is typically taught in the Improve stage of training, the FMEA has a place in other phases as well. But before practitioners can gain varied benefits from the tool, they must first be clear on how to use it.

虽然通常讲FMEA都是应用在实训项目的改进阶段, 但在其他阶段也同样适用。而实训人员要想从这个工具中获得各种益处，就必须首先弄清楚怎样运用它。

By Luca Bencini and Steve Pautz 作者：卢卡•本茨尼和史蒂文•鲍茨

The failure mode and effects analysis (FMEA) tool has several variations. In transactional environments, it is sometimes referred to as an EMEA – where E stands for human errors. Other variations include the process FMEA (pFMEA) and design FMEA (dFMEA). The fundamental purpose of any FMEA, however, is to identify, evaluate and take actions to reduce risk of failure.

故障/失效模式与后果分析（FMEA）工具可细分为几种。在与人有关的环境，有时叫做EMEA, E代表人为失误。其他的包括过程FMEA(pFMEA)以及设计FMEA(dFMEA)。不管怎么样，所有FMEA的主要目的是确认、评估以及采取措施降低故障的风险。

Just as there are many variations of the FMEA, there are also many uses for the tool within Six Sigma projects. Although it’s typically taught in the Improve stage of training, it has a place in other phases as well. But before practitioners can gain varied benefits from the tool, they must first be clear on how to use it.

FMEA有许多种，因而在六西格玛项目中它也相应有多种用途。虽然通常讲FMEA都是应用在实训项目的改进阶段, 但在其他阶段也同样适用。而实训人员要想从这个工具中获得各种益处，就必须首先弄清楚怎样运用它。

How it Works它是怎么起作用的？
Before proceeding with how to use an FMEA within the different phases of a Six Sigma project, it is best to review some key FMEA terms:

要想在六西格玛项目的不同阶段研究怎样运用FMEA，最好先回顾一下FMEA的主要术语：

Failure mode – The way in which a process can fail
故障/失效模式—过程中可能会出现的失效点/问题点

Effect – The impact on the process or customer requirements as a result of the failure
失效后果—故障模式对过程或者客户需求的影响

Severity – The impact of the effect on the customer or process
严重度—失效后果对客户或者过程影响的程度

Root cause – The initiating source of the failure mode
故障根本起因—故障模式的最初来源

Occurrence (or frequency) – How often the failure is likely to occur
发生率（或者频度）—故障可能发生的频率

Detection – The likelihood that the failure will be discovered in a timely manner, or before it can reach the customer.
探测度—故障被及时发现或者到达客户端之前被发现的可能性。

Risk priority number (RPN) – The value computed by multiplying the values assigned to Severity, Occurrence and Detection
风险顺序数—严重度、频度和探测度三者相乘得出来的数据。

In a pFMEA, failures (or errors) occur at a process step. The effects of the failure may be felt immediately after the failure occurs, or they may be felt downstream of the process. Conversely, root causes of the failure may occur immediately before the failure, or way upstream in the process.
在pFMEA,中，故障(或失误)发生在一个工序。故障的后果在故障发生后立即就能感受到，或者在下一道工序才能够发现。相反,故障的根本起因可能在故障发生之前就已经出现，或者发生在上一道工序。

Severity is always associated with the effect of the failure. What causes confusion is how to rate occurrence and detection. Occurrence can be associated with the failure mode or root cause, and detection can be associated with the root cause, failure mode or effect.
严重度总是与故障的后果相关，不难衡量。难的是怎样去评价频度和探测度。频度与故障模式或根本起因有关，探测度与根本起因、故障模式或失效后果有关。

To simplify the association, it is best to associate occurrence and detection with failure mode because usually the root causes have not yet been properly identified.
为了简化它们之间的联系，由于多数情况下根本起因还没有确定，最好把频度和探测度与故障模式联系起来分析。

The following is a user-friendly example of a pFMEA:
下面举一个容易理解的pFMEA 的事例：






Process Step
过程步骤 Failure Mode
失效模式 Occurrence
频度 Detection
探测度 Effect
失效后果 Severity
严重度 RPN
风险顺序数
Wrong destination on tag
标签上是错误的地点 3 5 Suitcase goes to the wrong destination
手提箱到达错误的地点 3 45
Putting tag on suitcase
把标签贴在手提箱上 Tag does not adhere to suitcase (falls off)
标签没有粘在箱子上（脱落） 2 3 Does not leave airport and goes to lost and found
箱子留在机场并转到失物招领 5 30


This simplifies the template in that occurrence and detection follow immediately after the failure mode and severity follows the effect – there is no ambiguity. A process step can have one or more failure modes, and each failure mode might have one or more effects. This means that if a spreadsheet is used, rows are added as failure modes and effects are added. It also allows practitioners to sort by RPN.
这是个简化的FMEA分析模板，其中频度和探测度紧随在失效模式之后，严重度随在失效后果之后（这不会产生歧义）。一个过程步骤可能有一个或多个失效模式，而每个失效模式可能有一个或者多个失效后果。这就意味着如果使用一个电子表格，把这些失效模式及失效后果的记录填写到行内，实习者也就能够根据RPN这个字段进行筛选。

Other columns can be added to the FMEA, such as root causes, controls, actions, responsible party and recalculated RPN based on actions. But for Six Sigma projects, the core of the FMEA is relatively simple and usually is sufficient for the Measure and Analyze phases.
FMEA分析模板中也能增加其他的列，如根本起因、控制方法、建议措施、责任团队、措施实施后的RPN，但是对于六西格玛项目，FMEA的要点相对是简单的，通常在测量和分析阶段使用如上所述的模板足够了。

As far as the numbers used in the FMEA, there are no generic scales for the three parameters (Occurrence, Detection and Severity). Each FMEA needs its own set of scales and when done in a brainstorming environment, a scale of 1 – 5 is usually sufficient; a scale of 1 -10 tends to increase complexity without additional benefit.
就使用在FMEA分析模板中的这三个参数（发生率、探测度和严重度）来讲没有通用的标准。每个FMEA都需要一套自己的标准，如采用头脑风暴法打分，分值范围为1 - 5通常就足够了，如分值范围为1 -10的话只会增加复杂性没有任何益处。

Flexible FMEA Focus灵活的FMEA关注点

While the overall approach of the FMEA does not change depending upon the DMAIC phase, the focus of its use does change.
当FMEA的整体分析方法没有随着DMAIC这五个阶段改变时，它的关注点就已经变化了。

In Measure, the FMEA can be used as a prioritization tool to understand and fine tune the focus of a Lean Six Sigma project. In addition, it also can be used to determine what can go wrong with the process, and what data the team should collect as part of its process metrics.
在测量阶段，可以把FMEA当作一种优化工具来看待并用来微调精益六西格玛项目的关注点。另外，也可以用来测定生产过程中发生了什么故障，团队需要采集什么数据作为过程度量的参考。

Example: A team launched a project to reduce reprocessing of materials in a sterilization line. To determine where to focus the initial efforts, the team created a detailed process map, followed by an FMEA to identify failure points in the process that resulted in re-sterilization. Once the FMEA was created, resulting in severity, occurrence and detection estimates, the team focused their project on four areas to eliminate or mitigate failure points.

例如:某团队启动了一个旨在减少无菌线原料返工的项目，为了确定首先从哪里开始着手，团队制定了一个周密的流程图，随后通过FMEA识别生产线中导致细菌再生的故障点。一旦制定了FMEA，完成了严重度、频度和探测度评估，团队就会关注这个项目，从四个方面去消除或降低故障点。

In Analyze, the FMEA helps to address where to look for root causes. It should be noted, however, that an FMEA is not a tool to identify root cases; but, frequently practitioners can document root causes in an FMEA.
在分析阶段，FMEA帮助定位故障点的根本起因。值得注意的是，不管怎么样FMEA都不是识别根本起因的工具，但是使用者却经常在FMEA中证明根本起因的存在。

Example: Most processes are not stable, due to the existence of special cause variation. By identifying special causes (sometimes referred to as root causes), practitioners can work to eliminate them, resulting in a stable or more predictable process. For instance, a financial institution had unacceptable variation in its cycle time for processing loan applications. The Six Sigma team completed an FMEA for the whole process, which led to three problem areas (receipt of applications, location where the applications were received and type of loans) to focus on. Subsequently, they collected data and built detailed cause and effect diagrams to help identify root causes for these problem areas.
例子：由于存在特殊的原因变化，很多过程都是不稳定的。通过识别特殊原因（有时被认为是根本起因），使用者能够排除故障点从而建立一个稳定的和更好预测的过程。例如，一个金融机构在处理贷款申请周期上遇到不可接受的变化。六西格玛团队完成了整个过程的FMEA，主要关注三个方面问题（收到申请、收到申请的地点和贷款类型），接着他们收集数据并建立详细的因果图以帮助识别这些问题的根本起因。

In Improve, the FMEA may be used to test a solution or process improvement. This testing can make the solution or process more robust, and help identify corrective, preventive and mitigative actions should failures or errors crop up later.
在改进阶段，FMEA可以用来考查一个解决方案或者工艺改进。这种考查可以使它们更完善，并帮助识别可纠正的、可预防的和可缓解的故障点或意外隐患。

Example: In DMAIC projects and especially in Design for Six Sigma (DFSS) projects, a relatively easy way to “test” a solution is to do a table top exercise (rather than a pilot or full implementation). An FMEA can serve as such an exercise and help identify possible weak points. One example involves a process designed for individuals to send money overseas to relatives. It was a rather complex process in that it had to have proper checks and balances to minimize fraud and to provide an audit trail. Once the process was designed and reviewed by subject matter experts, the Six Sigma team did a detailed FMEA to find potential weak spots. As a result of this effort, changes to the process were made. Subsequently, the process was piloted and the FMEA was updated with the results of the pilot.

例子：在DMAIC六西格玛改进项目中，特别是在六西格玛设计（DFSS）项目中，考查一个解决方案相对容易的方法是做一次台面推演（而不是试用或者全面贯彻）。FMEA就能适合这样的演练并帮助识别可能的缺陷。举个例子来说吧，这是一个关于个人向海外亲属寄钱的设计流程。该过程相当复杂，因为必须有适用的检查和权衡来减少被欺诈的风险并能提供审核线索。一旦过程设计完成，并通过项目主题专家的审查，六西格玛团队就要制定一个周密的FMEA分析方案来找到潜在的缺陷。通过这种努力，对过程进行修正，然后试运行该过程，再根据试运行结果更新FMEA。

In the Measure, Analyze and Improve phases, an FMEA is typically the result of brainstorming because quantitative data is usually not available. However, in Control, an FMEA is updated based on real data and is helpful for continuous and ongoing improvement.
在测量、分析和改进阶段，FMEA通常是头脑风暴法的结果，因为此时还没有数据。但是在控制阶段，FMEA的更新是基于真实的数据的，并帮助持续不断的改进。

Example: By this stage, the Six Sigma team is ready to close out the project and transfer it to the process owner. It is critical, when appropriate, to also transfer the FMEA (typically the one done in the Analyze phase) to the process owner. This means that the process owner needs to understand the FMEA and, more importantly, how to update the FMEA based on real experiences and data. For instance, a manufacturing plant that produces gasoline tanks made out of plastic resin was experiencing a high level of regrind – meaning tanks that did not meet standards were recycled through a regrinding process. However, there was a limit to how much reground resin could be mixed with virgin resin, so there also was a high scrap rate, as not all the reground resin could be reused. The team made a number of changes to the process (temperatures, pressures, flow rates, curing time, etc.) and used the FMEA to help develop standard operating procedures (SOP). The process owner – who also was a project team member – understood the FMEA well and reviewed and updated it every six months based on process performance. Additionally, this activity resulted in further enhancements to the process.
例子：在这个阶段，六西格玛团队已经准备中止这个项目并把它转交给流程责任者。关键的是在适当时候，也要把FMEA（通常指在分析阶段完成的那个）转交给流程责任者。这就意昧着流程责任者需要懂得FMEA，更重要的是，根据实际经验和数据如何去更新FMEA。例如：一个用塑料树脂生产汽油桶的工厂正在进行高水准的二次粉碎工艺----也就是说生产的汽油桶不能满足要求需要通过二次粉碎进行回收处理。但是，二次粉碎的树脂和原始树脂混合的比例是有限制的，所以仍然存在很高的废品率，因为并不是所有经过二次粉碎的树脂都能用。团队针对这个工艺的参数进行了许多调整（温度、压力、流量、固化时间等等），并运用FMEA分析法建立标准的作业指导书(SOP)。流程责任者--也是这个项目团队的成员—他相当熟悉FMEA，并且每六个月根据进展情况进行一次核查和更新，同时这项活动（FMEA）使二次粉碎工艺水平也得到了进一步提高。

About the Authors: Luca Bencini and Steven Pautz are Master Black Belts and senior managing consultants with IBM in the Strategy & Change practice. Luca has more than 25 years of experience in Lean Six Sigma as a practitioner and consultant. He also has degrees in chemical engineering and economics from MIT and an MBA from Harvard. Steve has 30 years of experience working in quality in service, manufacturing and government organizations. He has an engineering degree from Pratt Institute and an MBA from Southern New Hampshire University. They can both be reached at IBMLean@us.ibm.com.

关于作者：卢卡.本茨尼和史蒂文.鲍茨是两位黑带大师，是IBM策略和变更控制方面的高级管理咨询师，卢卡作为精益六西格玛方面的从业者和咨询师具有25年以上的工作经验，他也有麻省理工学院的化工和经济学方面的学士学位以及哈佛大学的MBA学位。史蒂文在服务、制造企业和政府部门有着30年的质量工作经历。他有布拉特学院的工程学士学位和南新罕布什尔大学的MBA学位。通过邮箱IBMLean@us.ibm.com可以联系到他们。