Failure Mode Effect Analysis (FMEA)

Prepared by :- Mr. Deepak Sahoo , Consultant

Training Program on

FMEAFailure Mode and Effects Analysis

Presented by : - Mr. Deepak Sahoo


Day Plan @ 5th Jan 2013.

Start time – 10.15 AM End Time : 1 PM

FMEA Part 1 – 10.15 AM – 11.45 PM

FMEA Part 2 – 12.15 PM - 01.00 PM

Break time @ 11.45 PM for 30 minutes

FMEA Part - 1 FMEA Part - 2Break


Agenda

FMEA History

What is FMEA

Definitions

What it Can Do For You

Types of FMEA

Team Members Roles

FMEA Terminology

Getting Started with an FMEA

The Worksheet

FMEA Scoring


Why we need FMEA video


Do it right the first time.

Why does it always seem we

have plenty of time to fix our problems, but never enough

time to prevent the problems by

doing it right the first time?


Accident Rate in Aviation industry.

The 2011 global accident rate (measured in hull losses per million flights) was 0.37, the equivalent of one accident every 2.7 million flights.

0.1 0.45 0.34 0.8 0.72

1.87

7.41

0

1

2

3

4

5

6

7

8

N O R T H A M E R I C A

E U R O P E N O R T H A S I A

A S I A -P A C I F I C

M I D D L E E A S T A N D

N O R T H A F R I C A

L A T I N A M E R I C A

A F R I C A

ACCIDENT RATE IN AVIATION INDUSTRY

Data collected from IATA.http://www.iata.org/pressroom/pr/pages/2011-02-23-01.aspx


Murphy’s Law

“Everything that can fail, shall fail”

This is known as Murphy’s Law and is one of the main reasons behind the FMEA technique.

Consequently, during the design of a system or product, the designer must always think in terms of:

What could go wrong with the system or process?

How badly might it go wrong?

What needs to be done to prevent failures?


The Bathtub curve


FMEA Video - 1


How it Origin ?

• This “type” of thinking has been around for hundreds of years. It was first formalized in the aerospace industry during the Apollo program in the 1960’s.

• Department of Defense developed and revised the MIL-STD-1629A guidelines during the 1970s.

• Ford Motor Company published instruction manuals in the 1980s and the automotive industry collectively developed standards in the 1990s.


What is FMEA ?

• FMEA Stands for Failure mode effect Analysis.

• FMEA is a tool that allows you to:

• Prevent System, Product and Process problems before they occur

• Reduce costs by identifying system, product and process improvements early in the development cycle

• Create more robust processes

• Prioritize actions that decrease risk of failure

• Evaluate the system, design and processes from a new vantage point


A Systematic Process

FMEA provides a systematic process to:

Identify and evaluate

potential failure modes

potential causes of the failure mode

Identify and quantify the impact of potential failures

Identify and prioritize actions to reduce or eliminate the potential failure

Implement action plan based on assigned responsibilities and completion dates

Document the associated activities


Published Guidelines

• J1739 from the SAE for the automotive industry.

• AIAG FMEA-3 from the Automotive Industry Action Group for the automotive industry.

• ARP5580 from the SAE for non-automotive applications.

Other industry and company-specific guidelines exist. For example:

• EIA/JEP131 provides guidelines for the electronics industry, from the JEDEC/EIA.

• P-302-720 provides guidelines for NASA’s GSFC spacecraft and instruments.

• SEMATECH 92020963A-ENG for the semiconductor equipment industry.


Rule of Ten (10)

If the issue costs $10,000 when it is discovered in the field,

then…

It may cost $1000 if discovered during the final test…

But it may cost $100 if discovered during an incoming inspection.

Even better it may cost $10 if discovered during the design or process engineering phase.


Benefits of FMEA.

Contributes to improved designs for products and processes.

Higher reliability

Better quality

Increased safety

Enhanced customer satisfaction

Contributes to cost savings.

Decreases development time and re-design costs

Decreases warranty costs

Decreases waste, non-value added operations

Contributes to continuous improvement


Type of FMEAs.

System/Concept “S/CFMEA”- (Driven by System functions) A system is a organized set of parts or subsystems to accomplish one or more functions. System FMEAs are typically very early, before specific hardware has been determined.

Design “DFMEA”- (Driven by part or component functions) A Design / Part is a unit of physical hardware that is considered a single replaceable part with respect to repair. Design FMEAs are typically done later in the development process when specific hardware has been determined.

Process “PFMEA”- (Driven by process functions & part characteristics) A Process is a sequence of tasks that is organized to produce a product or provide a service. A Process FMEA can involve fabrication, assembly, transactions or services.


FMEA Terminology 1

1.) Failure Modes: (Specific loss of a function) is a concise description of how a part , system, or manufacturing process may potentially fail to perform its functions.

2.) Failure Mode “Effect”: A description of the consequence or Ramification of a system or part failure. A typical failure mode may have several “effects” depending on which customer you consider.

3.) Severity Rating: (Seriousness of the Effect) Severity is the numerical rating of the impact on customers.

4.) Failure Mode “Causes”: A description of the design or process deficiency (global cause or root level cause) that results in the failure mode.

5.) Occurrence Rating: Is an estimate number of frequencies or cumulative number of failures (based on experience) that will occur (in our design concept) for a given cause over the intended “life of the design”.


FMEA Terminology 2

6.) Failure Mode “Controls”: The mechanisms, methods, tests, procedures, or controls that we have in place to PREVENT the Cause of the Failure Mode or DETECT the Failure Mode or Cause should it occur.

7.) Detection Rating: A numerical rating of the probability that a given set of controls WILL DISCOVER a specific Cause of Failure Mode to prevent bad parts leaving the facility or getting to the ultimate customer.

8.) Risk Priority Number (RPN): Is the product of Severity, Occurrence, & Detection.

Risk= RPN= S x O x D

9.) Action Planning: A thoroughly thought out and well developed FMEA With High Risk Patterns that is not followed with corrective actions has little or no value, other than having a chart for an audit


FMEA Video - 2


FMEA Process

Step 1 - Select a process to evaluate

Step 2 - Recruit a multidisciplinary Team

Step 3 - Have the team meet to list all the steps in the process

Step 4 - Have the team list failure modes and causes

Step 5 For each failure mode have the team assign a numeric value (Risk Priority Number (RPN)) for likelihood of

occurrence, likelihood of detection and severity.

Step 6 - Evaluate the results - Identify the failure modes with the top 10 highest RPNs.

Step 7 - Use RPNs to plan improvement efforts

Prepared by :- Mr. Deepak Sahoo , Consultant21

FMEA Core Team4 – 6 Members

Expertise in Product / ProcessCross functional

Honest CommunicationActive participation

Positive attitudeRespects other opinions

Participates in team decisions

Champion / SponsorProvides resources & support

Attends some meetingsPromotes team efforts

Shares authority / power with teamKicks off team

Implements recommendations

RecorderKeeps documentation of teams efforts

FMEA chart keeperCoordinates meeting rooms/time

Distributes meeting rooms & agendas

Facilitator“Watchdog“ of the process

Keeps team on trackFMEA Process expertise

Encourages / develops team dynamicsCommunicates assertively

Ensures everyone participates

Team Leader“Watchdog” of the project

Good leadership skillsRespected & relaxed

Leads but doesn’t dominateMaintains full team participation

Typically lead engineer

The FMEA Team Roles


Risk Priority Number(RPN)

RPN = Severity x Occurrence x Detection

RPN is used to prioritize concerns/actions

The greater the value of the RPN the greater the concern

RPN ranges from 1-1000

The team must make efforts to reduce higher RPNs through corrective action

General guideline is over 100 = recommended action


RPN Considerations

Rating scale example:

Severity = 10 indicates that the effect is very serious and is “worse” than Severity = 1.

Occurrence = 10 indicates that the likelihood of occurrence is very high and is “worse” than Occurrence = 1.

Detection = 10 indicates that the failure is not likely to be detected before it reaches the end user and is “worse” than Detection = 1.

RPN ratings are relative to a particular analysis.

An RPN in one analysis is comparable to other RPNs in the same analysis …but an RPN may NOT be comparable to RPNs in another analysis.


Risk Guidelines


Occurrence Ranking


Detection Ranking


FMEA Video - 3


Exercise (Perform A DFMEA on a pressure cooker)


Pressure Cooker Safety Features

1. Safety valve relieves pressure before it reaches dangerous levels.

2. Thermostat opens circuit through heating coil when the temperature rises above 250° C.

3. Pressure gage is divided into green and red sections. "Danger" is indicated when the pointer is in the red section.

Pressure Cooker FMEA

Define Scope:

1. Resolution - The analysis will be restricted to the four major subsystems (electrical system, safety valve, thermostat, and pressure gage).

2. Focus - Safety


Pressure cooker block diagram


Inputs for FMEA

Process flow diagram

Assembly instructions

Design FMEA

Current engineering drawings and specifications

Data from similar processes Scrap Rework Downtime Warranty

Process Function Requirement

Brief description of the manufacturing process or operation

The PFMEA should follow the actual work process or sequence, same as the process flow diagram etc.


Team Members for a FMEA

Process engineer

Manufacturing supervisor

Operators

Quality

Safety

Product engineer

Customers

Suppliers


Assumptions & Potential Failure Mode

The design is valid

All incoming product is to design specifications

Failures can but will not necessarily occur

Potential Failure Mode

How the process or product may fail to meet design or quality requirements

Many process steps or operations will have multiple failure modes

Think about what has gone wrong from past experience and what could go wrong


Common & Potential Failure ModesAssembly

Missing parts

Damaged

Orientation

Contamination

Off location

Torque

Loose or over torque

Missing fastener

Cross threaded

Machining

Too narrow

Too deep

Angle incorrect

Finish not to specification

Flash or not cleaned

Sealant

Missing

Wrong material applied

Insufficient or excessive material

Dry

Drilling holes

Missing

Location

Deep or shallow

Over/under size

Concentricity

angle


Potential Effects

• End user• Noise

• Leakage

• Odor

• Poor appearance

• Endangers safety

• Loss of a primary function

• performance

• Next operation• Cannot assemble

• Cannot tap or bore

• Cannot connect

• Cannot fasten

• Damages equipment

• Does not fit

• Does not match

• Endangers operator


Severity Ranking

How the effects of a potential failure mode may impact the customer

Only applies to the effect and is assigned with regard to any other rating

Potential effects of failure

Severity

Cannot assemble bolt(5)

Endangers operator(10)

Vibration (6)

Take the highest effect ranking (10)


Potential Causes

Equipment• Tool wear

• Inadequate pressure

• Worn locator

• Broken tool

• Gauging out of calibration

• Inadequate fluid levels

Operator• Improper torque

• Selected wrong part

• Incorrect tooling

• Incorrect feed or speed rate

• Mishandling

• Assembled upside down

• Assembled backwards


Occurrence Ranking

How frequent the cause is likely to occur

Use other data available Past assembly processes

SPC

Warranty

Each cause should be ranked according to the guideline


Detection

Probability the defect will be detected by process controls before next or subsequent process, or before the part or component leaves the manufacturing or assembly location

Likely hood the defect will escape the manufacturing location

Each control receives its own detection ranking, use the lowest rating for detection


RPN

RPN provides a method for a prioritizing process concerns

High RPN’s warrant corrective actions

Despite of RPN, special consideration should be given when severity is high especially in regards to safety

An RPN is like a medical diagnostic, predicting the health of the patient

At times a persons temperature, blood pressure, or an EKG can indicate potential concerns which could have severe impacts or implications


Recommended actions

Control

Influence

Can’t control or influence at this time


Recommended actions

Definition: tasks recommended for the purpose of reducing any or all of the rankings

Examples of Recommended actions

Perform:

Process instructions

Training

Can’t assemble at next station

Visual Inspection

Torque Audit


FMEA Video - 4


FMEA Video - 5


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Failure Mode Effect Analysis (FMEA)

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Transcript of Failure Mode Effect Analysis (FMEA)