Root Cause Analysis

Root Cause Analysis

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Root Cause Analysis • Root Root Caus Causee Analy Analysis sis is a meth method od that that is is used used to to addres addresss a problem or non-conformance, non-conformance, in order to get to the “root cause” of the the problem. It is used so we can correct or eliminate the cause, and prevent the problem from recurring. • Tradit Tradition ional al appl applica icatio tions ns of Root Root Cause Cause Anal Analysi ysiss – Resolution Resolution of customer customer complaints complaints and returns. returns. – Disposition of non-con non-conforming forming material material (Scrap and and Repair) via the Material Review process. – Corrective action action plans resulting resulting from internal internal and customer customer audits.

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Objective • Throug Through h this this traini training ng course course,, you you will: will: – Understand the meaning mean ing of “Root Cause” – Know the steps used to identify ide ntify the root cause of problems.

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What is Root Cause? • Root Caus Cau se is the fundamental breakdown or failure of a process which, when resolved, prevents a recurrence of the problem. Or, in other words

• For For a part partic icul ular ar prod produc uctt pro probl blem em,, Root Caus Cau se is the factor that, when you fix it, the problem goes away and doesn’t come back. • Root Cause Cause A n alys al ysii s is a systematic approach to get to the true root causes of our process problems.

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Philosophy of Root Cause Analysis • Each problem problem is an oppor opportuni tunity ty (“gol (“golden den nugget”) nugget”) because because it can tell a story about why and how it occurred. • It is is criti critical cal that that ever everyon yonee take take a perso personal nal and and activ activee role role in improving quality. • The “true” problem problem must be b e understood understoo d before action is taken. – Problems Problems are often often masked masked for a variety variety of reasons

• To do this this well well,, we we mus mustt be be – Both focused and openopen -minded mind ed – Both patient and quick – Above all, we w e must be relentless 5

We Perform Root Cause Analysis to Prevent Turnbacks and Customer Escapes from Recurring Defects found at:

Own Process Step

Next Process Step

Later Process Step

Before Reaching Customer

Found By Customer

$1 Ver y Minor

$ 10 Minor Delay

$100 Rework

$1,000 Significant Rework

$10,000 Warranty Cost

Cost:

Impact:

Reschedule of Work

Admin. Cost Delay in Deli Deliv very ery

Reputation

Additional Insp Inspec ecti tion on

Loss Loss of Mark Market et Shar Share e 6

Symptom Approach vs. Root Cause • If we do a poor job of of identif identifying ying the root root causes causes of our problems, problems, we will waste time and resources putting bandaids on the symptoms of the problem.

Symptom Approach

Root Cause

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“Err “Error orss are are oft often en a res resul ultt of of wor worke ker r carelessness.”

•

“Err “Error orss are are the the res resul ultt of of def defec ects ts in the the system. People are only part of the process.”

•

“We “We nee need d to to tra train in and and mot motiv ivat atee workers to be more careful.”

•

“We “We nee need d to to find find ou outt why why this this is happening, and implement mistake proofs so it won’t happen happen again.” again.”

•

“We “We do don n’t have ave the the time time or resources to really get to the bottom of of this problem.” problem.”

•

“Thi “Thiss is crit critic ical al.. We need need to fix fix it it for for good, or it will come back and burn us.”

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How do we do Root Cause Analysis? • Said Said sim simpl ply, y, Roo Roott Caus Causee Anal Analys ysis is is asking wh y the problem occurred, and then continuing to ask why that happened until we reach the fundamental process element that failed.

Why???

• The followi following ng examp example le illus illustra trates tes the basics basics of of Root Root Cause Cause Analysis.

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Fishbo Fishbone ne Diag Diagram ram - A Usefu Usefull Tool Tool • Using a fishbone fishbone diagram diagram while brainstorming brainstorming possible causes helps you to focus on the various possibilities. Some useful categories: Materials

People

Instructions

Environment

Problem

Machines

PM

Mea easu suri ring ng//Te Test st Eq Equ uip ip..

Des esig ign n

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Example: The Washing Machine Problem ProblemDescription Description

“Machine “Machineisis22weeks weeksold old (Serial (Serial#2345017). #2345017). When When doing doingthe thefourth fourthload loadof of clothes, clothes,IIheard heardaaloud loudnoise noise and andthe themachine machinestopped! stopped! ItIt wouldn’t wouldn’t re-start.” re-start.”

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Verify the Complaint Problem Problem Verification Verification

Service Servicetechnician technicianchecks checks washing washingmachine machineoperation operation to totest testprocedure procedure(#8496). (#8496). The Themachine machinedoes doesnot not operate. operate.

? ? Y Y H W W HDetermine

Determine the theCause. Cause. 11

Investigate Why Power Off?

Machine Unplugged?

Machine Machine Doesn’t Doesn’t Work Work Fuse Missing?

Fuse Blown

Fuse Blown?



Investigate Why Electrical Overload?

Motor Overheated?

Fuse Fuse Blown Blown Lightning Storm?

Motor Overheated

Power Surge?

Corrective CorrectiveAction Actionfor for Specific SpecificDeficiency: Deficiency: Replace Replacethe theFuse Fuse

? ? Y Y H W W H Determine


Investigate Why Cooling Fan?

Fly-Wheel Loose?

Motor Motor Overheated Overheated Shaft Damaged?

Motor Mis-Installed?

Shaft Damaged



Investigate Why Wrong Belt?

Bearing Destroyed?

Shaft Shaft Damaged Damaged

Mis-Handled? Mis-Installed?

Bearing Destroyed

Incorrect Tolerance/Fit?



Investigate Why Bearing Loads?

Wrong Bearings?

Bad Bearings?

Bearing Bearing Destroyed Destroyed Seal Omitted?

Corrective CorrectiveAction Actionfor for Specific SpecificDeficiency: Deficiency: Replace Replacethe theMotor Motor

Cause of Failure: Seal Omitted

Loss of Lube

? ? Y Y H W W HWas Seal

Was Seal Omitted?? Omitted?? 16

Root Cause of our Example? Parts Shortage

Inadequate Work Instructions?

Seal Seal Omitted Omitted

Fell Out? Operator Error?

Missed Operation?

Root Root Cause Cause -Inadequate Inadequate Work WorkInstructions Instructions

But..... is it?

Inadequate

Appropriate 17

Root Cause of our Example? Parts Shortage

Inadequate Work Instructions?

Seal Seal Omitted Omitted

Fell Out? Operator Error?

Missed Operation?

Root Root Cause Cause -Inadequate Inadequate Work WorkInstructions Instructions Appropriate

But.....

Inadequate

is it?

Can the design be changed to eliminate the need for a seal? Can the design be changed changed to make it impossible impossible to omit the seal? seal? Can a fixture be made to make it impossible to omit the seal?

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Tools Used in Root Cause Analysis Y

X BRAINSTORMING

START

PARETO CHART

FISHBONE DIAGRAM

SCATTER DIAGRAM

VALUE LSL

USL UCL X

N

?

LCL

TIME Y

RUN CHART

CONTROL CHARTS

HISTOGRAM

8

6

+

4

2

7

5

STOP FACTOR A

FLOWCHART

TREE DIAGRAM -

+

FACTOR C

3

1 -

FACTOR B

-

+

DESIGN OF EXPERIMENTS

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Brainstorming WHAT I S I T? Brainstorming is a process in which a group quickly generates generates as many ideas as it can on a particular problem and/or subject.

WHY I S I T USEFUL USEFUL ? Brainstorming Brainstorming is useful because it can help a group of people ut ilize its collective brainpower to generate many ideas in a short period of time. It stimulates creativity and promotes involvement and participation.

WHEN I S I T USED? USED? To help clarify mutual expectations and devise ground rules related to a team’s way of operating.

H OW I S I T DONE? •Identify a topic, problem or issue and make sure there is mutual understanding of the task and objective. Write the topic on a flip chart. •Each person presents one idea going in sequence (Round Robin). If a person doesn’t have an idea, pass and move on to the next person. person. •All ideas are recorded on a flipchart. •There is no evaluation or discussion during the session. •Focus is on quantity of ideas, not the quality. •When all ideas are exhausted, take a break. When you come back, people may have more ideas to add to the list. •Keep the idea generation separate from the evaluation or analysis of ideas.

BRAINSTOR BRAINSTORM M I NG GUI DELI NES: NES: •Generate as many ideas as possible. •Encourage free-wheeling. •No criticism is allowed, either positive or negative. •Equal opportunity to participate. •Record all ideas. •Let the ideas incubate. During analysis ideas should be evaluated, further analyzed and refined prior to taking further action.

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Fishbone Diagram WHAT IS IT? The Fishbone Diagram (also known as the Cause & Effect Diagram) is a technique to graphically identify and organize many possible causes of a problem (effect).

WHY IS IT USEFUL USEFUL ? Fishbone Diagrams Diagrams help identify the most most likely ROOT ROOT CAUSES of a problem. They can also help teach a team to reach a common understanding of the problem. This tool can help focus focus problem solving and reduce subjective decision making.

WHEN I S I T USED? USED? When the need exists to display and explore many possible possible causes of a specific problem or condition. This diagram allows the the team to systematically analyze cause & effect relationships. It can also help with the identification of ROOT CAUSES.

WHAT DOES I T LOOK LI KE?

BOWLING PROCESS INPUTS PEOPLE

METHODS

ATTITUDE

ALCOHOL INTAKE AMOUNT OF BALL LIFT HOW MANY ON TEAM? - P A CE CE EVERYONE SHOW UP?

MEASUREMENT

CURVE OR STRAIGHT BALL USE WRIST BAND? LENGTH OF ARMSWING

USE OF ALLEY ARROWS

SCOREKEEPER - MANUAL OR AUTO

# OF STEPS ON APPROACH

AMOUNT OF P RACTICE

USE RAG TO WIPE OFF BALL

TYPE OF WRIST BAND

PROBLEM: ACHIEV ACHIEVE E HIGHER HIGHER BOWLING SCORES

TEMPERATURE

AUTO PINSETTER SHOES USED

BALL WEIGHT

LANE OIL BALL CLEANER

MACHINES

BALL MATERIAL

RAG CLEAN

MATERIALS

NOISE FROM OTHER BOWLERS TIME OF YEAR HUMIDITY

ENVIRONMENT

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Fishbone Diagram (cont.) H OW I S I T DONE? •Name the effect; determine the specific problem to be analyzed. Draw the diagram with a process arrow to the effect and draw a box around it. •Decide what the major categories of the causes are (i.e., people, machines, measurement, materials, methods, environment, policies, etc.). •Label categories important important to your situation. situation. Make it work for you. you. •Brainstorm all possible causes and label each cause under the appropriate category. •Post the diagram where others can add causes to it (i.e., experts, affected people, process owners, etc..). •Analyze causes and eliminate trivial and/or frivolous ideas. •Rank causes and circle the most likely ones for further consideration and study. •Investigate the circled causes. Use other techniques to gather data and prioritize findings.

GUIDELINES •Try not to go beyond the span of control of the group. •Promote participation by everyone concerned. •Keep chart up to date so it can be used throughout the improvement cycle.

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P EO EO PL PL E

M AC AC HI HI NE NE S

ME EA A SU SU RE RE ME ME NT NT

Questions to Ask When Performing RCA PROBLEM

•

•

PEOPLE –

Was the document properly interpreted?

–

Was the information properly disseminated?

–

Did the recipient understand the information?

–

Was the proper training to perform the task administered to the person?

– –

Was too much judgment required to perform the task? Were guidelines for judgment available?

–

Did the environment influence the actions of the individual?

–

Are there distractions in the workplace?

–

Is fatigue a mitigating factor?

–

How much experience does the individual have in performing this task?

MATER MATERIAL IAL METH METHOD ODS S

ENVIRO ENVIRONM NMEN ENT T

MACHINES –

Was the correct tool used?

–

Is the equipment affected by the environment?

–

Is the equipment being properly maintained (i.e., daily/weekly/monthly preventative maintenance schedule)

–

Was the machine properly programmed?

– –

Is the tooling/fixturing adequate for the job? Does the machine have an adequate guard?

–

Was the tooling used within its capabilities and limitations?

–

Are all controls including including emergency stop button button clearly labeled and/or color coded or size differentiated?

–

Is the machine the right application for the given job?

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P EO EO PL PL E




u

MEASUREMENT


– –

Does the the gage have have a valid calibra calibration tion date? date? Was the the proper proper gage used used to measure measure the part, part, process, process, chemica chemical, l, compound, etc.?

–

Was a gage capabili capability ty study ever ever performed? performed?


– Do measurements measurements vary vary significan significantly tly from operato operatorr to operator? operator? – Do operators operators have have a tough tough time using using the prescrib prescribed ed gage? – Is the gage gage fixturing fixturing adequa adequate? te? – – u

u

Does the the gage have have proper measure measurement ment resolut resolution? ion? Did the environ environment ment influen influence ce the measuremen measurements ts taken? taken?

MATERIAL – –

Is a Material Material Safety Data Data Sheet (MSDS) (MSDS) readily readily available available?? Was the material material properly properly tested? tested?

–

Was the material material substitut substituted? ed?

–

Is the supplier supplier’s ’s process process defined defined and controlled controlled??

–

Were quality quality requireme requirements nts adequate adequate for part part function? function?

–

Was the material material contaminated contaminated??

–

Was the materia materiall handled handled properly properly (stored, (stored, dispens dispensed, ed, used & dis disposed) posed)??

ENVIRONMENT –

Is the process process affected affected by temperature temperature changes changes over over the course course of a day? day?

– –

Is the process process affected affected by humidi humidity, ty, vibration vibration,, noise, noise, lighting, lighting, etc.? Does the the process process run in a control controlled led environm environment? ent? 24

P EO EO PL PL E




u

METHODS


–

Was the caniste canister, r, barrel, barrel, etc. labeled labeled properly? properly?

–

Were the workers workers traine trained d properly properly in the procedu procedure? re?

– –

Was the testing testing performe performed d statistical statistically ly significan significant? t? Have I tested tested for true true root cause cause data? data?

–

How many many “if necessar necessary” y” and “approx “approximatel imately” y” phrases phrases are found found in this process?

–

Was this this a process process generated generated by an Integr Integrated ated Product Product Developme Development nt (IPD) Team?

–

Was the IPD IPD Team properly properly represented represented??

–

Did the the IPD Team employ employ Design Design for for Environme Environmental ntal (DFE) (DFE) principl principles? es?

– –

Has a capability capability study study ever been performed performed for for this process? process? Is the process process under under Statistical Statistical Process Process Control Control (SPC)?

–

Are the work instru instruction ctionss clearly written written??

–

Are mistake mistake-proofi -proofing ng devices/techni devices/techniques ques employed? employed?

–

Are the work instru instruction ctionss complete? complete?

–

Is the tooling tooling adequatel adequately y designed designed and controlled controlled??

– –

Is handling/pac handling/packaging kaging adequatel adequately y specified? specified? Was the process process changed? changed?

–

Was the design design changed? changed?

–

Was a process process Failure Failure Modes Modes Effects Effects Analysis Analysis (FMEA) (FMEA) ever performed? performed?

–

Was adequate adequate sampling sampling done? done?

–

Are features features of the process process critical critical to safety safety clearly clearly spelled spelled out to to the Operato Operator? r?


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Fishbone Diagram Exercise PEOPLE

METHODS

MEASUREMENT

CHALLENGE: HIT CONSISTENTLY A FASTBALL BETWEEN 85-95 MPH.

MACHINES

MATERIALS

ENVIRONMENT

Q.) What are the factors that drive hitting a baseball? 26

Asking Why: sometimes Simple, sometimes Complex Root Cause Analysis sometimes requires the additional resources. Expert Lab Complex, High-Tech Equipment

Component Failed

Failure Analysis Lab, More Sophisticated Equipment

Circuit Board Malfunctioned

Sophisticated Tools or Analysis Equipment Controller Failed

s e c r u o s e R

Simple Tools Hose Disconnected

1 Person (Brainpower)

Not Plugged In

Complexity 27

Summary •

Root Root Cause Cause Analys Analysis is is a metho method d to to focu focuss our our effor efforts ts on on the the true true “Root Causes” of escapes, so that we truly prevent their reoccurrence.

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Root Root Cause Cause Analy Analysis sis help helpss us us red reduc ucee tur turnb nbac acks ks and and fru frustr strati ation on,, maintain customer satisfaction, and reduce costs significantly.

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Each Each prob proble lem m is an op oppo port rtun unit ity. y. It cont contai ains ns the the inf infor orma mati tion on needed to eliminate the problem. But to identify the root cause, we have to ask “Why?” over and over, until we reach it.

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Root Cause Analysis

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