failure analysis failure analysis … private failure analysis has four major objectives:...

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Nash Asrar,Nash Asrar,Nash Asrar,Nash Asrar, Ph.DMaterials Support and Failure Analysis Group

EMS Centers, Sugar Land, TX – 77478

SMTA Expo & Tech Forum, Stafford Center, Houston, March 6, 2014

FAILURE ANALYSIS FAILURE ANALYSIS FAILURE ANALYSIS FAILURE ANALYSIS –––– Cause Cause Cause Cause

to Preventionto Preventionto Preventionto Prevention

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� FAILURE AND FAILURE ANALYSIS

� CONDUCTING FAILURE ANALYSIS

� TOTAL FAILURE MANAGEMENT – A Failure Prevention Process

� FAILURE OF FAILURE ANALYSIS

� EFFECTIVNESS of FAILURE MANAGEMENT – Success Stories

� CONCLUDING REMARKS

TopicsTopicsTopicsTopics

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Why Do Failures Occur??Why Do Failures Occur??Why Do Failures Occur??Why Do Failures Occur??

� Aggressive operation conditions (use or misuse)

� Improper maintenance (intentional or unintentional)

� Improper testing or inspection

� Assembly errors

� Fabrication/manufacturing errors

� Design errors (stress, material selection, and

assumed material condition or properties)

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Failure: A part in service –

� has become completely inoperable , or

� is still operable but incapable of satisfactorily performing

its intended function, or

� has deteriorated seriously, to the point that it has

become unreliable or unsafe for continued use.

Failure Analysis:

Failure analysis is an engineering approach to determining how and

why (cause and root cause) an equipment or a component has failed.

Failure and Failure AnalysisFailure and Failure AnalysisFailure and Failure AnalysisFailure and Failure Analysis

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Failure analysis has four major objectives:

� Understanding that failure occurred

� Determine the symptoms or the apparent manner a component has

failed (the mode)

� Determine the mechanism, primary cause(s) and root cause of the

failure

� Recommend feasible corrective and preventive action(s)

…..Failure analysis is a journey, prevention is the goal….March 12, 2014 5

Aims and ObjectivesAims and ObjectivesAims and ObjectivesAims and Objectives

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Conducting Failure Analysis (FA) Conducting Failure Analysis (FA) Conducting Failure Analysis (FA) Conducting Failure Analysis (FA) ––––

a science and an arta science and an arta science and an arta science and an art

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� The failure investigation report is expected to answer two questions:

“What is the problem?” and “What is the root cause of the problem?”

� Conclusion(s) must be brief, clear and adequately supported by

findings/test results provided in the report.

� In recommendation(s) FA engineer suggests the “best” solution to

prevent the failure in the future and failures of similar equipment.

� Recommended optimal corrective action(s) must address the root

cause of the problem, be technically feasible, cost effective and

timely (good compromise of quality and time).

March 12, 2014 8

Concluding Failure AnalysisConcluding Failure AnalysisConcluding Failure AnalysisConcluding Failure Analysis

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FailureFailureFailureFailure----Prevention ProcessPrevention ProcessPrevention ProcessPrevention Process

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Failure analysis is a journey, PREVENTION is the Failure analysis is a journey, PREVENTION is the Failure analysis is a journey, PREVENTION is the Failure analysis is a journey, PREVENTION is the goalgoalgoalgoal

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FailureFailureFailureFailure

Failure AnalysisFailure AnalysisFailure AnalysisFailure AnalysisIdentification of cause and root cause of the

failure

PreventionPreventionPreventionPreventionImplementation of findings/learning of failure

analysis

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Concepts Of Failure AnalysisConcepts Of Failure AnalysisConcepts Of Failure AnalysisConcepts Of Failure Analysis

� Mission - Find out how the

failure occurred

� Purpose - Determine the cause

of the failure

� Affiliation - Not regarded as an

integral part of the

product development

and manufacturing

process

- Prevention

- Determine the root cause of

the failure

- Regarded as an integral

part of the product

development and

manufacturing process

Traditional Modern

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March 12, 2014 12

Cause and EffectCause and EffectCause and EffectCause and Effect

Effect Cause

Injury Caused By Fall

Fall Caused By Slipped

Slipped Caused By Wet surface

Wet surface Caused By Leaky valve

Leaky valve Caused By Seal Failure

Seal Failure Caused By Not maintained

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The Elemental Causal SetThe Elemental Causal SetThe Elemental Causal SetThe Elemental Causal Set

EffectEffectEffectEffect

Open fire

ConditionConditionConditionCondition

Oxygen, etc.


Combustible

material


Match exists

ActionActionActionAction

Match strike

EffectEffectEffectEffect


ActionActionActionAction

Caused

ByCaused

By

Elemental Causal Set

Example:

Why open fire?

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� Elemental causal set is the fundamental causal element of all that

happens. It is made up of an “effect” and its immediate cause, which

consists of an action and one or more conditions.

� Actions are momentary cause that bring conditions together to

cause an effect – Most easily recognized.

� Conditions are causes that exist over time prior to the companion

action – often ignored.

� Effect can be prevented by eliminating either action or conditions or

preventing them from combining. Example - Application of coating (a

barrier layer) for corrosion control.

March 12, 2014 14

The Elemental Causal SetThe Elemental Causal SetThe Elemental Causal SetThe Elemental Causal Set

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Cause Cause Cause Cause vsvsvsvs Root CauseRoot CauseRoot CauseRoot Cause

Primary cause

� Set of conditions or

parameters from which the

failure began

� For short term solution

Root Cause

� A process or procedure which

went wrong

� For long term solution

Hidden root

cause(s)

Evident

cause(s)

Systems and

indicators

Key point is that this is not typically obvious and often has not

been considered ……and most often hidden from view

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Collapse of a Building

Primary cause – Use of poor

quality of cement

Root cause – Budget constraint

OR poor specs, bad supplier, bad management, poor QC…..

Cause Cause Cause Cause vsvsvsvs Root CauseRoot CauseRoot CauseRoot Cause

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March 12, 2014 17

Difference between Primary Cause and Root Cause

Primary Cause (set of

conditions or parameters)Root Cause (process or procedure)

The finish on a machine part

was not as specified

The failure to check the finish after parts are

machined

The incorrect heat treatment

was applied

The failure to ensure that the heat treatment

furnace had sufficient control of changes in

temperature to produce the desired

microstructure and mechanical properties in

the part/component.

Corrosion and cracking of

drilling tools due to corrosive

environment

Lack of implementation of guidelines to

control corrosivity of environment (drilling

fluids).

Manufacturing defect of

component X, Y, Z….

Lack of a procedure to ensure provision of

proper instruction/design to the manufacturer

and/or lack of procedure for QC (quality

check)

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� TFM is a process through which knowledge of failure

mechanisms can be applied and lessons learned can be

implemented to reduce or prevent failure.

� Components of TFM;

� Failure mechanism investigation

�Root cause analysis

� Implementation of the lessons learned March 12, 2014 18

Total Failure Management (TFM)Total Failure Management (TFM)Total Failure Management (TFM)Total Failure Management (TFM)

Failure AnalysisFailure AnalysisFailure AnalysisFailure Analysis

Failure Failure Failure Failure

ManagementManagementManagementManagement

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March 12, 2014 19

Steps of TFM Objectives

Failure

Mechanism

Investigation

Sample/site preservation Ensure the correct physical evidence

is collected and analyzed properly to

determine the physical cause of failure

or failure mechanism

Failed sample collection

Data collection and integration

Laboratory analysis

Reporting/documentation

Root cause

determination

Cause and effect analysis Determine the root cause (process or

procedure) that allowed the failure to

occur

Causal factor charting

Root cause identification

Recommendations

Implementing

lessons learned

Develop engineering solutions Ensure that lessons learned are

implemented as solutions and

embedded in the organizational

culture

Communication

Action tracking

Feed back to FM system


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Failure of Failure AnalysisFailure of Failure AnalysisFailure of Failure AnalysisFailure of Failure Analysis

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In the following situations or work behavior, objectives of the failure

analysis may not be achieved:

� Assuming a primary/apparent cause to be the root cause

� Determining the failure cause by assumption

� Collecting insufficient information, collecting sample from wrong

location and ending an analysis before it is completed

� Refusing to recognize that a failure can or does exist

� Shutting down the malfunctioning equipment

� Discarding failed parts

� No documentation

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Achievements of Failure AnalysisAchievements of Failure AnalysisAchievements of Failure AnalysisAchievements of Failure Analysis

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Electronic Components Failure

Killer Gold – Embrittlement and Whiskers

� Irregular and large voids in Pb-

Free (SN96) solder

� Gold content in solder >9wt.%

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AuSn4

Ag3Sn

• 100 thermal cycles at - 40oC to 155oC

• Formation of brittle crystals of Au-rich (light grey) and Ag-rich IMC (grey)



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Tin-Whiskers on Pb-Free solder

• Whisker formation during the thermal cycle at - 40oC to 180oC

• Islands of Sn-Ni-Au IMCs in the solder matrix

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Plotted for SnPb 60/40 solder

RESOLUTION

� Gold plating thickness for solder joints = 2 - 10 microinches immersion gold layers are adequate to offer solderability.

� Gold content in solder = 3 wt.% max



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Prevention of Field Failure

Corrosion of the Drill Collar(Drill Collar ENP001 and ENP004 failed at the RIG)

pH of the drilling fluid

• reported = 10

• determined = 8.8

Dissolved oxygen (DO)

• Mud was not treated with oxygen scavenger

• Degasser was out of service

• Determined 4.36 ppm DO in the mud

H2S in the downhole fluid

• Mud was contaminated with 15ppm H2S

• Mud was not treated with sulfide scavenger.

Collar cleaning after POOH

• With high pressure brakish water

EXCESSIVEEXCESSIVEEXCESSIVEEXCESSIVE

CORROSION CORROSION CORROSION CORROSION

andandandand

CRACKINGCRACKINGCRACKINGCRACKING

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COLLAR - Excessive corrosion and cracking on the OD and ID surfaces



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CHASSIS - Excessive corrosion pitting on the OD surface



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• High pressure pumps and clean water was made available

RESOLUTIONS

pH of the drilling fluid

• Proper alkali dosing

• Determined = 10 by HACH’s pH every 4 hr.

Dissolved oxygen (DO)

• Mud was treated with oxygen scavenger

• Degasser was repaired

• Determined <1ppm DO in the mud

H2S in the downhole fluid

• Mud was treated with sulfide scavenger

• H2S was eliminated

Collar cleaning after POOH

• High pressure pumps and clean water was made available

NEGLIGBLE

CORROSION


Corrosion of the Drill Collar

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Negligible corrosion



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Field Failure

Corrosion Control of the Drill Collar - Qatar

0

5

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15

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40

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25 40 36

2006 2007 2008

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Worn out

corroded

Cracked

Job Count

avg/month

After implementation of corrosion

control guidelines for mud

treatment and tool cleaning:

• Collar damages per job has

reduced

• Service life of the collar

raised from 800 hrs (2005 –

2007) to 2000 hrs (2008)

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Concluding RemarksConcluding RemarksConcluding RemarksConcluding Remarks

� Failure Analysis + Failure Management = Failure Prevention

� Failure analysis is a journey, PREVENTION is the goal

� Failure analysis is a science and an art

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March 12, 2014 35

Concluding RemarksConcluding RemarksConcluding RemarksConcluding Remarks

Actions Required

� Adoption - Adopt the modern concept of failure analysis.

� Documentation - Eliminate the errors of knowledge by

developing quality documentation, and sharing information.

� Implementation - Develop a process to ensure the

implementation of the corrective measures � Follow TFM.

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Thanks!

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failure analysis failure analysis … private failure analysis has four major objectives:...

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