FME 461 - Latest News in Mechanical and Manufacturing...

FME 461

ENGINEERING DESIGN II

© H. Jama, 2012

Failure modes Effects and

Analysis (FMEA)

Learning outcomes

To understand the use of Failure Modes Effect

Analysis (FMEA) - Engineering

To learn the steps to developing FMEA

To summarize the different types of FMEA

To learn how to link the FMEA to delivery of

quality products or processes?

To review some examples of FMEA

To perform a FMEA exercise

© H. Jama, 2012

FMEA – by William Goble

A rather simple technique, the failure modes

of each component in a given system are

listed in a table, and the effect of that failure

is postulated and documented.

The method is systematic, effective, and

detailed, although sometimes called time-

consuming and repetitive. The reason the

method is so effective is every failure mode

of every single component is examined.

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© H. Jama, 2012

FMEA

A structured approach to:

Identifying the ways in which a product or process can fail

Estimating risk associated with specific causes of failure

Prioritising the actions that should be taken to reduce risk

Evaluating design validation plan (product) or current control plan (process)

© H. Jama, 2012

How is this relevant to the

design engineer?

Allows us to identify areas of design or process

that most impact our customers/patients

Helps us identify how and where our product,

system or process is most likely to fail or is

failing

Pin-point product or process failures that are

difficult to detect

© H. Jama, 2012

History of the FMEA

Idea was conceived in the 1940s

First used in the 1960’s in the Aerospace industry

during the Apollo missions

In 1974, the Navy developed MIL-STD-1629

regarding the use of FMEA

In the late 1970’s, the automotive industry was driven

by liability costs to use FMEA – litigation

Later, the automotive industry saw the advantages of

using this tool to reduce risks related to poor quality –

warranties

There is an SAE standard J 1739 for conducting

FMEA in design and processes

© H. Jama, 2012

FMEA – other names

DFMEA - design

PFMEA - Process

FMECA - Criticality

FMEDA –Diagnostic

These all mean the same and fundamentally

have the same steps.

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© H. Jama, 2012

Similar systems/techniques

APQP – advanced Product Quality planning

QS 9000 – automotive industry

ISO9001 – although it has mainly been

relegated to paper pushing

HAZOP – Hazard and Operability Study used

in the petro-chemical industry

CHAZOP – Control hazards Operability

analysis

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© H. Jama, 2012

What is failure mode?

A Failure Mode is:

The way in which a component, sub-

assembly, product, input, or process could

fail to perform its intended function

Things that could go wrong

© H. Jama, 2012

FMEA

What

Failure Modes & Effects Analysis is a

methodology to evaluate failure modes and

their effects in designs and in processes.

© H. Jama, 2012

FMEA

Why

Methodology that facilitates process improvement

Identifies and eliminates concerns early in the development of a process or design

Improve internal and external customer satisfaction

Focuses on prevention

FMEA may be a customer requirement

FMEA may be required by an applicable Quality System Standard

In our case – we are trying to come up with a systematic way of improving process delivery

© H. Jama, 2012

FMEA

How

Team identifies potential failure modes for design functions or process requirements

They assign severity to the effect of this failure mode

They assign frequency of occurrence to the potential cause of failure and likelihood of detection

Team calculates a Risk Priority Number by multiplying severity times frequency of occurrence times likelihood of detection

Team uses ranking to focus process improvement efforts

© H. Jama, 2012

FMEA - example

© H. Jama, 2012

Risk definition

The Oxford English Dictionary defines risk as ―(Exposure

to) the possibility of loss, injury, or other adverse or

unwelcome circumstance; a chance or situation involving

such a possibility‖

Risk consists of a hazard and the likelihood of

occurrence

Example – Highly flammable fuel like LPG but we have

reduced the risk of usage by reducing likelihood of

occurrence of an explosion

Occasionally we get some explosions but they occur

infrequently. Hence LPG is not a risky fuel to use

© H. Jama, 2012

Risk cont..

Example of risk management: A

NASA model showing areas at high

risk from impact for the International

Space Station.

Source: Wikipedia

© H. Jama, 2012

When to conduct an FMEA

Early in the process improvement investigation

When new systems, products, and processes are

being designed or introduced

When existing designs or processes are being

changed/improved

When carry-over designs are used in new

applications

After a system, product, or process functions are

defined, but before specific hardware is selected or

released to manufacturing

© H. Jama, 2012

Example form - revisited

© H. Jama, 2012

Types of FMEA

Design

Analyzes product design before release to

production, with a focus on product function

Analyzes systems and subsystems in early

concept and design stages

Process

Used to analyze service/manufacturing and

assembly processes

© H. Jama, 2012

FMEA – A team tool A team approach is necessary.

Team should be led by a responsible manufacturing engineer or technical person, or other similar individual familiar with FMEA.

A healthcare professional with experience and familiar with the FMEA process – for healthcare applications. You can invite engineers for an outsider’s perspective

The following should be considered for team members:

Design Engineers, Operators

Process Engineers—Reliability

Materials Suppliers—Suppliers

Customers

© H. Jama, 2012

FMEA procedure

1. For each process input (start with high value

inputs), determine the ways in which the input can

go wrong (failure mode)

2.For each failure mode, determine effects

Select a severity level for each effect

3.Identify potential causes of each failure mode

Select an occurrence level for each cause

4.List current controls for each cause

Select a detection level for each cause

© H. Jama, 2012

FMEA procedure - Cont

5. Calculate the Risk Priority Number (RPN)

6. Develop recommended actions, assign

responsible persons, and take actions

Give priority to high RPNs

MUST look at severities rated a 10

7. Assign the predicted severity, occurrence,

and detection levels and compare RPNs

© H. Jama, 2012

FMEA input and outputs

© H. Jama, 2012

FMEA

The relationship between failure modes

and effects is not always 1 to 1.

© H. Jama, 2012

Severity, Occurrence &

Detection

Severity

Importance of the effect on customer requirements (Patient outcome)

Often can’t do anything about this

Occurrence

Frequency with which a given cause occurs and

creates failure modes

Detection

The ability of the current control scheme to detect or prevent a given cause

© H. Jama, 2012

Rating Scales

There are a wide variety of scoring ―anchors‖,

both quantitative or qualitative

Two types of scales are 1-5 or 1-10

The 1-5 scale makes it easier for the teams

to decide on scores

The 1-10 scale allows for better precision in

estimates and a wide variation in scores

(most common)

© H. Jama, 2012

Scales

Severity

1 = Not Severe, 10 = Very Severe

Occurrence

1 = Not Likely, 10 = Very Likely

Detection

1 = Likely to Detect, 10 = Not Likely to Detect

© H. Jama, 2012

Risk Priority Number (RPN)

RPN is the product of the severity times

occurrence times detection scores.

© H. Jama, 2012

FMEA – Simple Example

We will conduct an FMEA on the truck stop

example we used to create a C&E Matrix

A Black Belt (Six Sigma – Manufacturing)

wants to improve customer satisfaction with

the coffee served at the truck stop

The process map and completed Cause and

Effect (C&E) matrix follow

© H. Jama, 2012

Truck stop coffee steps

Step 1 – create a process map

Step 2 – Cause and effect sheet

A) For each input, determine the potential

failure modes

For each failure mode, identify effects and

assign severity

© H. Jama, 2012

Step 1- create a process map

© H. Jama, 2012

Cause & Effect

© H. Jama, 2012

a) Potential failure modes

© H. Jama, 2012

b) Identify effects & Assign

Severity

© H. Jama, 2012

c) Identify potential causes for

each failure mode & assign a

score

© H. Jama, 2012

d) List current controls and

assign a score

© H. Jama, 2012

Application to the service

industry

I am involved in training medical practitioners

in the use of continuous improvement tools

Mccain C. (2006) ―Using FMEA in a service

setting” Quality Progress Vol 39 Issue 9

22/1/2013

© H. Jama, 2012

Literature on FMEA

There are very good sources such as

Vinodh S. & Santosh D. (2012) ―Application of FMEA to an automotive leaf spring manufacturing organization”. TQM Journal Vol 24 Issue 3

Pollack S. (2005) “ Create a simple framework to validate FMEA performance” ASQ Six Sigma Forum magazine Vol 4 Issue 4.

Reid R.D. FMEA something old, something new, Quality Progress 38 (5), 2006

James L. & Kovach J. Improving Home Healthcare Using Sigma Six,Proceeding of the 2009 Industrial Engineering Research conference

© H. Jama, 2012

Assignment 2- Learning from

failure

On 29th August 2013, Kenya lost 41 innocent

people to a tragic road accident. The bus

they were travelling in rolled at Ntulele near

Narok, killing 35 of them on the spot. The

crash occurred at 1am.

Conduct an FMEA on the recent bus tragedy

in the Narok region

Look at the crash from an education,

engineering and enforcement angle

FME 461 - Latest News in Mechanical and Manufacturing...

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