Innovative Approach to FMEA facilitation

Govind Ramu, P.Eng,ASQ CQMgr, CQE, CSSBB, CQA, CSQE, CRE,ASQ Fellow,QMS 2000 Principal Auditor IRCA (UK)Past Section Chair Ottawa Valley- ASQ Canadahttp://www.asq.org/sixsigma/about/govind.html

History of the FMEA

• The FMEA discipline was developed in the United States Military in 1949 (Military Procedure MIL-P-1629, titled Procedures for Performing a Failure Mode, Effects and Criticality Analysis.

• The first formal application of FMEA discipline was used in aerospace in mid 60s.

• It was used as a reliability evaluation technique to determine the effect of system and equipment failures. Failures were classified according to their impact on mission success and personnel/equipment safety.

• Reference: SAE J 1739 and AIAG.

• The FMEA discipline was developed in the United States Military in 1949 (Military Procedure MIL-P-1629, titled Procedures for Performing a Failure Mode, Effects and Criticality Analysis.

• The first formal application of FMEA discipline was used in aerospace in mid 60s.

• It was used as a reliability evaluation technique to determine the effect of system and equipment failures. Failures were classified according to their impact on mission success and personnel/equipment safety.

• Reference: SAE J 1739 and AIAG.

A structured approach to

Identify the way in which a design / process can fail to meet critical customer requirements. Estimating the risk of specific causes with regard to the failures.Evaluating the Current control plan for preventing the failures from occurring. Prioritizing the actions that should be taken to improve the design/ process.

A structured approach to

Identify the way in which a design / process can fail to meet critical customer requirements.Estimating the risk of specific causes with regard to the failures.Evaluating the Current control plan for preventing the failures from occurring.Prioritizing the actions that should be taken to improve the design/ process.

What is FMEA?

FMEA is very beneficial to conduct while designing a product or process. Design FMEA should be done during initial design of the product.Process FMEA should be done during design of manufacturing process. Process FMEA can be performed for legacy products and processes also if the process carry high risks to product quality, customer, safety, etc.

FMEA is very beneficial to conduct while designing a product or process.Design FMEA should be done during initial design of the product.Process FMEA should be done during design of manufacturing process. Process FMEA can be performed for legacy products and processes also if the process carry high risks to product quality, customer, safety, etc.

When to use FMEA?

Different Types of FMEA

An analytical technique used primarily by design responsible engineer/Team to assure potential failure modes; causes and effects have been addressed for design related characteristics.

Design FMEA

An analytical technique used primarily by manufacturing responsible engineer/Team to assure potential failure modes; causes and effects have been addressed for process related characteristics.

Process FMEA

System, Subsystem, Component level FMEA are possible scopes

Definitions

Critical Characteristics are Special Characteristics defined by organization that affect customer safety and/or could result in non- compliance with government regulations and thus require special controls to ensure 100% compliance.

Critical Characteristics

Detection is an assessment of the likelihood that the Current Controls (design and process) will detect the Cause of the Failure Mode or the Failure Mode itself, thus preventing it from reaching the Customer.

Detection

Severity is an assessment of how serious the Effect of the potential Failure Mode is on the Customer.

Severity

Occurrence is an assessment of the likelihood that a particular Cause will happen and result in the Failure Mode during the intended life and use of the product.

Occurrence

The Criticality rating is the mathematical product of the Severity and Occurrence ratings. Criticality = (S) X (O). This number is used to place priority on items that require additional quality planning.

Criticality

The Risk Priority Number is a mathematical product of the numerical Severity, Occurrence, and Detection ratings. RPN = (S) X (O) X (D). This number is used to place priority on items than require additional quality planning.

Risk Priority Number

Definitions

A Function could be any intended purpose of a product or process. FMEA functions are best described in verb-noun format with engineering specifications.

Function

Failure Modes are sometimes described as categories of failure. A potential Failure Mode describes the way in which a product or process could fail to perform its desired function (design intent or performance requirements) as described by the needs, wants, and expectations of the internal and external Customers.

Failure Mode

FMEA elements are identified or analyzed in the FMEA process. Common examples are Functions, Failure Modes, Causes, Effects, Controls, and Actions. FMEA elements appear as column headings in the output form.

FMEA Element

Customers are internal and external departments, people, and processes that will be adversely affected by product failure.

Customer

A Cause is the means by which a particular element of the design or process results in a Failure Mode.

Cause

An Effect is an adverse consequence that the Customer might experience. The Customer could be the next operation, subsequent operations, or the end user.

Effect

Current Controls (design and process) are the mechanisms that prevent the Cause of the Failure Mode from occurring, or which detect the failure before it reaches the Customer.

Current Controls

FMEA- A team based effort.

• Input is required from shop floor-supervision through to management.

• Engineering/ R & D• Service.• Reliability.• Purchasing.• Quality Engineering.• Supplier Quality Engineering• Manufacturing• EH & S, ROHS

Review design and process using a functional block diagram, system design, architecture and process flow chart.

Use a brainstorming approach to gather potential failure modes.Use historical data from customer returns, complaints and internal

issues from comparable products or processes. List potential effects, both internal and external, of failure.Assign severity, occurrence and detection (SOD) rankings based on

the effect, probability of occurrence of the root cause and ability to detect the root cause before the failure mode happens.

Calculate the risk priority number (RPN) by multiplying severity, occurrence and detection rankings. Also, calculate criticality by multiplying severity and occurrence.

Prioritize the failure modes (risks) based on RPN score and/or criticality.

Take actions to eliminate or reduce the risks.

FMEA Traditional approach

FMEADEVELOPMENT

PROCESS

FMEADEVELOPMENT

PROCESS

FMEAForms

FMEAForms

FMEATEAMFMEATEAM

FMEA#

FMEA# Part No.Part No.Process

I.D.Process

I.D.Prepared

ByPrepared

ByOwnerOwner Due DateDue Date

ProcessFunctionProcessFunction

CoreTeamCoreTeam

Pot FailureMode

Pot FailureMode

FMEA DATE

FMEA DATE

FailureEffects

FailureEffects SeveritySeverity

OccurrenceOccurrencePotCausesPot

CausesClassClass CurrentControl

CurrentControl DetectionDetection

Flow chart

TRADITIONALAPPROACH

Major issues

•Quality of the FMEA•Quantity of Completion•Fundamental issues- Bundling of causes!

•Fill it, Shut it, Forget it*!

* Courtesy: Famous 80s advertisement campaign from Hero Honda Motor cycle manufacturers India. (On fuel economy)

During development:Not understanding the fundamentals of failure mode effects analysis

(FMEA) development. Inadequate representation in the team from subject matter experts. Failing to identify the right inputs for the FMEA. Poor planning before assembling for brainstorming and failure ranking.

During implementation:Breaking the sessions into weekly meetings (thus losing continuity). Using severity, occurrence and detection (SOD) scales that are not

representative of the industry, product family or process group.Failing to learn from the risks exposed at the component and module-

level FMEA while drafting at the system level FMEA. Allowing the rigor of the tool to drive the intensity of initial interactions,

causing fatigue for participants.

Pitfalls

During implementation: (Continued)Wasting time on risk-rating debates. Failing to follow through on recommended actions. Failing to drive actions across the board in a systemic way. Failing to integrate the learning from design and process FMEAs or to link to

control plans, critical to quality characteristics and critical to process parameters.

During sustainability:Not incorporating the identified, mitigated risks into manufacturing

guidelines to be used for future product development. Failure to keep the FMEA alive by including feedback from subsequent

stages of the product life cycle.

Pitfalls (Continued)

Sources of data

Supplier causedE.g. Out of Spec, non conformance, etc.

Process ControlE.g. Out of Spec, Contamination

Product or Process ChangesE.g. failure, etc.

Internal Ongoing Reliability issues

Periodic SurveillanceE.g. Out of Spec

Customer Returns- DPPM data

Product Design related E.g. Performance, reliability, etc.

Process Design related E.g. Opportunity for error

Process ControlE.g. Out of Spec, Contamination

Customer causedE.g. damage, S/W error, etc.

Supplier causedE.g. Out of Spec, non conformance, etc.

Customer complaints on product or system performanceWith No product return or RMA

DFMEA / PFMEA (Potential)

Failure mode-Effects-Causes

% Defective, Defects per Unit

Customer Complaints

Process control issuesE.g. traceability, yield, etc.

Supplier feedback

Product/Process Design RelatedE.g. tight unrealistic tolerances, Capability.

Similar sources of data from comparableProducts, processes of Organization

BODY OF KNOWLEDGE

Known Industry failure-Technical journals, publications,-Conferences, etc.

External Knowledge

Scope Process (Process FMEA)

• Formulate Cross functional Team• Understand Customer/Process Requirements.• Define the start and end of the Process• All team members to walk and observe the process.• Get the assemblers/ process operators to explain the process.• Team makes notes and observations.

Brainstorm all potential causes for the failure modes

INNOVATIVE APPROACH Inputs: Process Flow charts, Manufacturing WI,Historical process defect pareto, lessons learned, Etc

Brainstorming Software feature

Microsoft VISIO®

Brainstorm all potential local & end effects for the failure modes

Brainstorm all potential failure modes

• Utilize process flow chart-break down each step.• Use knowledge of previous and existing parts/processes.• Review all quality information E.g.: Scrap, rework, RMA,etc.• Talk to internal and external customers.

Failure Modes are sometimes described as categories of failure. A potential Failure Mode describes the way in which a product or process could fail to perform its desired function (design intent or performance requirements) as described by the needs, wants, and expectations of the internal and external Customers.

Failure Mode

An Effect is an adverse consequence that the Customer might experience. The Customer could be the next operation, subsequent operations, or the end user.

Effect

Example:Does not fit, Cannot load or fasten, poor performance, intermittent failure erratic operation.Example:

Fiber Damage, Contamination, hairline crack, Dimension oversize.

Identify potential effects of failure

For each failure mode, identify the effect(s) on the current or next process or customer downstream in manufacturing/assembly process.

Describe the effects of failure in terms of what the customermight notice or experience.

Cause and Effect Cascade with an example

Design

Environmental Exposure

Moisture

Corrosion

Poor Contact (High

Resistance)

Insufficient Current

Dim Bulb

CauseEffect

Cause

Effect

Cause

Effect

CauseEffect

CauseEffect

Cause

Effect

Cause = DesignEffect = Env. Exposure

Cause = Env. ExposureEffect = Moisture

Cause = MoistureEffect = Corrosion

Cause = CorrosionEffect = High Resistance

Cause = High ResistanceEffect = Insufficient Current

Cause = Insufficient CurrentEffect = Dim Bulb

Courtesy: Elsmar Cove

Determine severity rating

Severity is an assessment of the seriousness of the effect of Potential failure mode to the customer.Severity applies to effect only.

Note: Assigning severity rating should be performed as a teamIncluding customer representative and or Design FMEA engineer.If the customer affected by a failure mode is a user outside the plant, teamShould consult them and assign the rating.

Identify all potential causes of failure

How the failure could occur? Describe in terms of factorsThat can be corrected or controlled.

Note: Experiments may have to be conducted to determine causes using technicalProblem solving.

There could be more than one cause for each failure!!

Example:Improper torque, Inaccurate gauging, inadequate lubrication, etc.

Management should have control on the cause identified. The cause should be at the root level.

Determine occurrence rating

Occurrence is how frequently the specific failure causeMechanism is projected to occur.

Note: If available from a similar process, statistical data should be used to determineOccurrence ranking.

Define Current Controls

Systematic methods/devices in place to prevent or detectFailure modes or causes (before the effect happens).

Example: Poke-Yoke, automated control for setup verification

Determine detection ranking

Detection is an assessment of the probability that the current process control will detect a Potential cause.

Note: Random quality checks are unlikely to detect the existence of an isolatedDefect and should not influence the detection ranking. Sampling done on aStatistical basis is a valid detection control.

Also assess the ability of the process control to detectLow frequency failure modes or prevent from going Into the next process.

Current Controls

Design and Process controls are grouped according to their purpose.Type (1)

These controls prevent the Cause or Failure Mode from occurring, or reduce their rate of occurrence.

Type (2)

These controls detect the Cause of the Failure Mode and lead to corrective action.

Type (3)

These Controls detect the Failure Mode before the product reaches the customer. The customer could be the next operation, subsequent operations, or the end user.

The distinction between controls that prevent failure (Type 1) and controls that detect failure (Types 2 and 3) is important. Type 1 controls reduce the likelihood that a Cause or Failure Mode will occur, and therefore affect Occurrence ratings. Type 2 and Type 3 Controls detect Causes and Failure Modes respectively, and therefore affect Detection ratings.

Calculate the Risk Priority Numbers

The Risk Priority Number is the product of Severity (S) X Occurrence (O) X Detection (D) rankings.

This value should be used to rank order the concerns In the process using Pareto. The RPN will be between 1and 1000.

Criticality is severity multiplied by occurrence. This is also an important metric. RPN can be reduced by improving the detection, but the process issue may remain intact. Criticality can be reduced only by improving the capability or redesign.

Prioritize Corrective actions

•Concentrate on the Highest RPN•Do not lose sight on effects with high severity.•Think of how the occurrence can be reduced?•How the detection can be improved?•Where applicable use Mistake proofing techniques.•Introduce changes in a controlled manner.

Reassess rankings when action completed

• FMEA must be a Live document. • Review Regularly.• Reassess rankings whenever changes made to product/process.• Add any new defects or potential problems when found.

References

• Potential Failure Mode & Effects Analysis, fourth edition, Automotive Industry Action Group, 2008.

• Govindarajan “Govind” Ramu, “Metrics That Trigger Actionable Discussions: Prioritize Process Improvements Using Gauge R&R and SPC Capability,” ASQ Six Sigma Forum.

• Traditionally, NGT is used to collect ideas: www.asq.org/learn-about-quality/idea-creation- tools/overview/nominal-group.html In FMEA development, it can be used to collect scores of SOD.

• Elsmar Cove archived file references.

BibliographyQuality Training Portal, Resource Engineering Inc., “What You Need to Know About Failure Mode and Effects Analysis (FMEA),” www.qualitytrainingportal.com/resources/fmea/index.htm.May 2009 QP – Standards Outlook – Dan Reid- Major Upgrade.