Pt3 Maintenance 11

8/9/2019 Pt3 Maintenance 11

1/83

Tim. C. Claypole.

Manufacturing Optimisation

Prof. Tim. C. Claypole.

School of Engineering.

Reliability & Maintenance


2/83

Tim. C. Claypole.

Principal Areas That May

Contribute To Reliability

Design

ManufactureOperation

Maintenance


3/83

Tim. C. Claypole.

ReliabilityAssumes

Initial Performance > Desired Performance

Otherise fails immediately!

"ailure Performance # Desired Performance


4/83

Tim. C. Claypole.

"ailure could be$ %ac& of function

Manufacturing tolerances

Inade'uate performance


5/83

Tim. C. Claypole.

Accessing Ris& of "ailure "ailure Mode and (ffect Analysis

Considers indi)idual components

In hat ays can the component fail *o does the failure effect the performance

"ault Tree Analysis +"TA,

%oo&s at possible modes of failure Identifies hat combination of e)ents is

re'uired to produce failure


6/83

Tim. C. Claypole.

-ources of -ystem

Information (perience +direct and related,

Most Accurate

Most Costly

Tests/ -imulation and Confirmation Testing elements cheaper than testing hole

More basic the component/ less )alid

Results increasingly out of contet

Analysis %east accurate

Can direct testing to ma&e it more effecti)e


7/83Tim. C. Claypole.

"ailure Mode and (ffect

Analysis +"M(A,Applied to$

Design

Process Planning

Maintenance +"M(CA,

"ailure mode/ effect and criticality analysis



"M(A consists of specifying

for each component$ "ailure mode *o component can fail

(ach component may ha)e multiple failure modes

(ach failure could ha)e more than one effect Cause of failure

(ffect on system -afety/ dontime/ repair etc.

Correcti)e Actions



-uccessful "M(A depends on (pertise of the analyst

Management commitment



Design "M(AAssumes all parts are correctly

manufactured

Considers only problems associatedith Design or materials specification



Design "M(A Categories of potential failures

Tolerances beyond capability of the process

"ailure to meet customer epectation 0nacceptable ser)ice life

Total failures in ser)ice

Reduce life due to corrosion Reasonably foreseeable customer misuse

Problems of installing customer1s system



Current Status

No.

me

ue

Function or

process

Failure

Mode

Efect o

Failure

Cause o

Failure

Current

Controls

OCC SEV DET RPN

234

tom

cket

e A

To provide

engine front

support

Buckling

failure of

bracket

vertical walls

ngine drop

!cooling fan

fouls

radiator"

#ncorrectl$

speci%ed

material

t&ickness

'tress

(eport

'(1))

3 * 3 +2

Test to T(

1,)

- - -

'ervice

loads in

e.cess of

design loads

/ot $et

establis&ed

4 * 0 2**

-

orrosion radual loss

of strengt&leading to

structural

failure

#nadeuate

protectivetreatment

speci%ed

rotective

treatment5 salt

spra$ tests

are

speci%ed

T( 1,)

2 * 2 32



-tatus Rating of 2 +loest, to 23 +most se)ere,

OCC 4 occurrence

-(5 4 se)erity D(T 4 detection

RP6 4 Ris& Priority 6umber

7+OCC,8+-(5,8+D(T, *ighlights priorities

(stimate ne RP6 to 9ustify actions


14/83

Tim. C. Claypole.

Current Status Revised Status

No.

me

ue

Failure

Mode

Efect o

Failure

Cause o

Failure

OCC SEV DET RPN Recommended

Corrective

ction

ction Ta!en OCC SEV DET RPN

234

tom

cket

e A

Buckling

failure of

bracket

vertical walls

ngine drop

!cooling fan

fouls

radiator"

#ncorrectl$

speci%ed

material

t&ickness

3 * 3 +2 Tests to be carried

out to T( 1,) to

verif$ stress

report '( 1))

Tests to speci%ed

load proves

adeuate static

strengt&

2 * 2 32

- - -

'ervice

loads in

e.cess of

design loads

4 * 0 2** 6eri%cation b$

road load

data7 test bed

reuired 5

drawing controls

establis&ed

(oad load7 test

data con%rms

design loads are

satisfactor$

2 * 3 4*

-

orrosion radual loss

of strengt&

leading to

structuralfailure

#nadeuate

protective

treatment

speci%ed

2 * 2 32 #nstallation to be

reviewed after

road and

laborator$ tests

8aborator$ 5

(oad tests were

carried out 5 no

corrosion wasevident

2 * 2 32


15/83

Tim. C. Claypole.

Process "M(AAssumes product design is correct

Analyses failures due to planning or

operation deficiencies


16/83

Tim. C. Claypole.

Considers each stage of the

processAc'uisition of materials

Machine setting

Machining:Assembly

*andling

Inspection

Despatch


17/83

Tim. C. Claypole.

"ailures due to$ Pro)ision of incorrect material

('uipment errors

Operator errors

Contamination

*ouse&eeping

*andling damage


18/83

Tim. C. Claypole.

Current Status

No.me

ue

Functionor process

FailureMode

Efect oFailure

Cause oFailure

CurrentControls

OCC SE

V

DET RPN

234

om

cket

e A

Drill &oles 9oles out of

position

Di:cult ass$

of engine

mounting

#ncorrect

location in

drill %.ture

Operator 5

#nspection

measurement

wit& vernier

on freuenc$

basis

, + ; 21)

Drill &oles 9oles

undersi


19/83

Tim. C. Claypole.

Current Status Revised Status

No.me

ue

Functionor process

Cause oFailure

CurrentControls

OCC SE

V

DET RPN RecommendedCorrective

ction

ction Ta!en OCC SEV DET RPN

234

tom

cket

e A

Dril l &oles #ncorrect

location in

drill %.ture

Operator 5

#nspection

measurement

wit& vernier

on freuenc$

basis

, + ; 21) ositive location

on %.ture 5 %nal

acceptance gauge

>i.ture location

modi%ed 5

acceptance gauge

in use

2 + 2 2*

-

Drill &oles #ncorrect drill

siirst o? c&eck 5

use of acceptance

gauge

(ecommended

actions

implemented

2 ; 1 12

-

>orm

bracket

oor raw

material

identi%cation

5 storage

Operator

local

knowledge

; * 0 432 #dentif$ raw

material location

racks and colour

coding

(ecommended

actions

implemented

2 * 0 144


20/83

Tim. C. Claypole.

Design or Process "M(A

"unction or process "ailure mode

(ffect of "ailure

Cause of "ailure

Current Controls Current -tatus

OCC

-(5

D(T RP6

Recommended

correcti)e action

Action ta&en Re)ised -tatus

OCC

-(5

D(T

RP6


21/83

Tim. C. Claypole.

"ault Tree Analysis

;egins ith list of ha


22/83

Tim. C. Claypole.

"ault trees consist of

branches connected by nodesA6D 4 all e)ents belo node must

occur for the e)ent abo)e the

node to occur

OR 4 at least one of the e)ents

belo must occur for the e)ent

abo)e to occur


23/83

Tim. C. Claypole.

"TA of a bra&e

%o bra&e fluid

=orn pads

"aultyMaster

Cylinder

Can1t stop!

"luid lea&

%ea&ing Cylinder;ro&en

pipe%oose ;leed


24/83

Tim. C. Claypole.

(ample of and?

%e)er on1t retract

=ea&

-prings

6o

lubricant


25/83

Tim. C. Claypole.

Do companies look after their company cars as well

as they look after their equipment?

Company car Eu 20 k eb press Eu ! million " Equi#alent 200 cars


26/83

Tim. C. Claypole.

=hy Maintain@

Reliability and A)ailability Customer Demands

-horter run lengths

-horter lead times Consistent uality BIT deli)ery

Return on capital in)estment

*igher production speeds More lost production per minute! %ess spare capacity

Men and machines


27/83

Tim. C. Claypole.

Despair or maintenance strate$y?

piral of breakdown dispair

% 'ro(uction loss from break(owns

& low pro(ucti#ity

2 Equipment worke( har(er to reco#er

lost pro(uction

) *reak(owns increase & more time is lost

! +ncrease( pro(uction pressure re(ucesmaintenance time e#en further


28/83

Tim. C. Claypole.

Maintenance Costs

(penditure in the (0 approaching of total

manufacturing turno)er an annual spend of beteen EFbillion and

E223billion

e'ui)alent to the total annual industrial output of

*olland

Around G million people in H3/333 companies

ere engaged in maintenance acti)ities =or&s Management+22,


29/83

Tim. C. Claypole.

0J maintenance spending

of annual sales turno)er

Tice 0J trade deficit

Three times the )alue of ne plant

in)estment

2F of boo& )alue


30/83

Tim. C. Claypole.

In diesel engines K3 of in ser)ice failures are due to

contamination of hich 3 are due to ear related

problems

Appro L3 of rolling element bearings fail due toimproper lubrication only 23 fail at normal fatigue

limit Courtesy of -hell


31/83

Tim. C. Claypole.

K of gear failures are due to ser)ice problems Incorrect lubrication

"oreign material

Corrosion

;earing failure

Inade'uate maintenance Continuous or shoc& o)erloading

2 ere ear related L o)erload related Courtesy of -hell


32/83

Tim. C. Claypole.

=hat Is "ailure@

A gear bo operating in a continuous process plant productionline

The -afety Office Calls for immediate shut4don

The Production Manager Maintenance staff can carry out an inspection at the net shut don

The Maintenance (ngineer Re'uests brief stoppage of production to chec& the oil le)el. *e ill

also continue to closely monitor the condition o)er the net tenty4

four hours

=hen ill it be dealt ith@


33/83

Tim. C. Claypole.

Industrial maintenance parallels health care development

Period Strategy Human health care Machine care

%,)0s *reak(own *eart attac& -ar$e bu($et. /fi it when broken1

%,0s 're#enti#e ;y4pass surgery 'erio(ic component replacement

%,30s 're(icti#e Disease detection Con(ition monitorin$. fi early

%,40s 'ro5acti#e Cholesterol N blood 'erformance monitorin$

pressure monitoring Contamination controlRoot cause diet control 6'M+Total Producti)e Maintenance,

E#olution of maintenance


34/83

Tim. C. Claypole.

Maintenance -trategies

;rea&don

Restorati)ePre)entati)e

Condition Monitoring

Pro4acti)e


35/83

Tim. C. Claypole.

-trategy depends on$

%ife

Impact on process

Detectability


36/83

Tim. C. Claypole.

"ailure Conse'uences

*idden failures

-afety and (n)ironmental

Operational


37/83

Tim. C. Claypole.

*idden failures

6ot apparent to operators Protecti)e de)ices hich do not fail safe

In themsel)es harmless Can lea)e organisation epose to

potential catastrophe

Ris& must be eliminated or minimised If the failure doesn1t ha)e a conse'uence/

then hat is the purpose of the part@


38/83

Tim. C. Claypole.


Does the failure maim or &ill@

Does it damage the en)ironment

If es/ then ris& must be eliminated orminimised


39/83

Tim. C. Claypole.

Operational Conse'uences

(conomic decision %oss of producti)ity

%oss of 'uality %oss of ser)ice

6on operational Conse'uences e.g. Pump failure

-tand by ta&es o)er

*o long to repair@

*o long is the organisation eposed to ris&@


40/83

Tim. C. Claypole.

;rea&don maintenance

Repair or replace on failure %ight bulb approach

Doesn1t need planning9ust response procedure

"ailure must ha)e no *-( implications

*o long does it ta&e to repair@


41/83

Tim. C. Claypole.

Cost of brea&don maintenance

%oss of a)ailability or need to maintain surplus capacity

*igh spares in)entory or long don times

6eed to maintain a brea&don cre

or long don time


42/83

Tim. C. Claypole.

Pre)entati)e maintenance

Change components before they fail automoti)e oil change

Planned shutdon can be integrated into or& schedule

A)oids brea&dons

pro)ided inter)al beteen componentreplacement correctly calculated


43/83

Tim. C. Claypole.

"or age related performance$

Desired

Performance

Performance of system

Initial Performance

"ailure

Time

P

erformance


44/83

Tim. C. Claypole.

Age Related "ailure

Progressi)e "ailure ith time e.g. ear


45/83

Tim. C. Claypole.

Probability of "ailure 4

;athtub cur)e

Time

Probability

of"ailure


46/83

Tim. C. Claypole.

Regions of ;athtub cur)e

Initial failures Burn in or infant mortality

Constant ris& Slightly rising probability

Normal operating region

=ear out Replacement zone


47/83

Tim. C. Claypole.

Age related failures in ci)il

aircraft systems L follo bath tub cur)e

G follo bath tub cur)e ithout section

2 +burn in, follo section G only ith a steady

increase in probability of failure ith time

7nly %%8 of components show a$erelate( failure


48/83

Tim. C. Claypole.

Probability of "ailure 4

6on age related

TimeProbability

of"ailure


49/83

Tim. C. Claypole.

6on age related failure cur)es

Probability rises to a constant le)el 7% of systems on civil aircraft

Constant failure rate 14% of systems on civil aircraft

Probability fall to a constant le)el

68% of systems on civil aircraft


50/83

Tim. C. Claypole.

F of components on ci)il aircraft

ha)e non age related failures =hy@

Multiple modes of failure

More comple the units 4 more modes offailure

Computers follo cur)e H initial high ris& falls to constant ris&


51/83

Tim. C. Claypole.

Cost of pre)entati)e maintenance

6e)er achie)e full life of components O)er fre'uent replacement is throing

money aay May not impro)e reliability

ci)il aircraft or computers


52/83

Tim. C. Claypole.

Con(ition Monitorin$

4 etraction of information from

machines to indicate their condition


53/83

Tim. C. Claypole.

Detect faults early when time & cost

to correcti#e is lowest

6emperature 9 :ibration 9 7il con(ition 9 'ower consumption

Con(ition monitorin$


54/83

Tim. C. Claypole.

Condition4based Maintenance

Principal Re'uirements$ D(T(CTIO6

Onset of change from benign to acti)e

mode DIA6O-I-

type/ se)erity and location

D(T(RMI6ATIO6 hat to do and hen


55/83

Tim. C. Claypole.

"our basic methods

Performance monitoring 5ibration monitoring

5isual

including thermography and sensual monitoring %ubricant monitoring

condition

chemical composition ear debris


56/83

Tim. C. Claypole.

Performance monitoring

Pumps pressure and poer consumption

Presses poer consumption

Monitoring your utilities bill

Is the consumption ecessi)e or increased


57/83

Tim. C. Claypole.

5ibration Monitoring Misalignment

a pea& at shaft speed %ooseness

typically 2/ G and H shaft speed

Imbalance a pea& at shaft speed

ear damage gear mesh fre'uency

Oil hirl $ beteen 3.LG and 3.LQ shaft speed

Rolling element bearings $ high fre'uency +en)elope analysis/ &urtosis/ shoc& pulse or spi&e energy,


58/83

Tim. C. Claypole.

Thermal imaging

6(C Thermo TracerT*K23G 4G33C to G33C

eneral thermal traces *ot spots in systems

Influence of cooling/

drying etc ..

Condition monitoring

*ot bearing

"ailing systems


59/83

Tim. C. Claypole.

%ubricant Analysis

%ubricant properties $

"orm a fluid film beteen loaded surfaces

Act as a coolant Carry aay contaminants +solid/ li'uid

and gaseous,

Act as a hydraulic medium

Protect against rust and corrosion


60/83

Tim. C. Claypole.

Simple Sensory Tests


61/83

Tim. C. Claypole.

O'T B/>#T A/A8@''

ase stud$ 1

1992 - US Air Force oil analysis programreported 190 serious problems in aircraft componentsprior to failure. Five ndings resulted in removal of

engines from F-1 aircraft prior to serious enginedamage - total cost avoidance! "1#$000$000.

ase stud$ 2

US navy oil analysis evaluation concluded t%at

&ust t%ree aircraft systems resulted in a return oninvestment of more t%an 1'() over oil monitoringcosts

O'T B/>#T A/A8@''

ase stud$ 1

1992 - US Air Force oil analysis programreported 190 serious problems in aircraft componentsprior to failure. Five ndings resulted in removal of

engines from F-1 aircraft prior to serious enginedamage - total cost avoidance! "1#$000$000.

ase stud$ 2

US navy oil analysis evaluation concluded t%at&ust t%ree aircraft systems resulted in a return oninvestment of more t%an 1'() over oil monitoringcosts


62/83

Tim. C. Claypole.

=ear And =ear Debris Characteristics

02

=Re4entrained

=ear Debris

"oreign Debris

+Contaminated,

Time

=ear and Debris

Production Rate

+concentration,

S -(M

S (lemental Analysis

S CompositionS Material

=ear DebrisMorphology )s.

=ear Mode

-i


63/83

Tim. C. Claypole.

Idealised Representation Of =ear Progression

Reacti)eone

Diagnostic capabilityre'uirement

=ear Debris

Production

Rate

Proacti)e one Reacti)eone

Acti)e =ear

+decreasing, ;enign =earActi)e =ear

+increasing,

Time

OIL & WEAR DEBRIS ANALYSIS

Trend Monitoring$ Detection and measurement of ear products

Diagnosis$ Oil Analysis

Morphological analysis of ear products

Trend monitoring

and diagnostic

capability


64/83

Tim. C. Claypole.

Particle "eatures 5s. =ear Characteristics

-


65/83

Tim. C. Claypole.

-pectrographic oil analysis

Monitoring traces of chemical composition e.g. copper from bearing surfaces

deterioration related to increased traces

-ource can be identified important if lubricant circulates around se)eral surfaces

0sed by Municipal bus operators

6orth sea oil rigs Courtesy -ansea %aboratory -er)ices

Magnetic Detector lug


66/83

Tim. C. Claypole.

Magnetic Detector lugipes


67/83

Tim. C. Claypole.

Representati)e Debris 4 R; 2 (ngine


68/83

Tim. C. Claypole.

%arge/ 3 mm chord idth/ se)eral microns thic&. -urface hea)ily

striated ith long straight edges. Typically occurs in gear ear.

-e)ere

-liding

Typically ferrous/ 2 > 3 mm diameterU generated from micro4crac&sunder rolling contact conditions

-pheres

Chun&y/ se)eral microns thic&U e.g./ G3 3 mm chord idth"atigue

Thin/ bright/ free metal particles/ typically 2mm thic&/ G3 3 mmchord idth/ ith holes in surface and e)en edge profile emanates

from mainly gear:rolling element bearing ear/ associated ith

fatigue action

%aminar

-arf4life chips of fine ire coils. Cause by abrasi)e Vcutting tool1

action

Cutting

Particles # G3 mm chord dimension and appro. 2 mm thic&. Results

from fla&ing of pieces from the shear4mied layer

Mild or

Rubbing

Description'article6ype

ear article Morp&ologicalDescriptors


69/83

Tim. C. Claypole.

Pro4acti)e maintenence

Identifying and eliminating causes of

failure

similar to "M(A e.g. rather than monitor a bearing for ear

caused by ingression of contaminating

particles/ eliminate the contamination

before it causes ear


70/83

Tim. C. Claypole.

Cost of maintenance

Item and conse'uential damage Dontime by unscheduled failure

Production loss

Maintenance team on stand by

(arly replacement Periodic component replacement

Monitor Cost of e'uipment

Monitoring Personnel/ training etc.


71/83

Tim. C. Claypole.

Changing maintenance profile


72/83

Tim. C. Claypole.

Maintenance -trategy"or each element strategy depends on$

%ife

"ailure Conse'uences

*idden failures 6ot detected but organisation eposed


(conomic conse'uences

%oss of producti)ity %oss of 'uality %oss of ser)ice


73/83

Tim. C. Claypole.

Operational Conse'uences

(conomic decision %oss of producti)ity

%oss of 'uality

%oss of ser)ice 6on operational Conse'uences

e.g. Pump failure -tand by ta&es o)er

*o long to repair@ *o long is the organisation eposed to ris&@


74/83

Tim. C. Claypole.

;enefits of Maintenance

Programme %ess unplanned stops More aare of e'uipment performance

and capability More fre'uently use non O(M consumables

Jno hich spares to ha)e in stoc&

Maintenance adapted to suite di)erseoperational demands


75/83

Tim. C. Claypole.

'ress ;pee(

3

23

G3

H3

L3

3

Q3

K3

F3

3233

Maintenance -ystem All

#G

G 4 L3

L3 4 Q3

Q3 4 K3

K3 4 F3

F3 4 3

3 4 233

Companies ith

Maintenance -ystem

Run faster

=hich came first@

-peed orMaintenance


76/83

Tim. C. Claypole.

-on$ *reak (own

323

G3

H3

L3

3Q3

K3

F3

3

233


6e)er

2 per year2 per 'uarter

2 per month

2 per ee&


77/83

Tim. C. Claypole.

;hort stoppa$es

3

23

G3

H3

L3

3

Q3

K3

F3

3

233


2 per year

2 per 'uarter

2 per month

2 per ee&

()eryday


78/83

Tim. C. Claypole.

Monitor Machine ;ensors

3

23

G3H3

L33

Q3

K3F3

3233

Maintenance

-ystem

All

-omething goes rong

(ternal ser)ice

Once a ee& bymaintenance

Once a shift by

maintenance

Once a shift by operator

Continuously


79/83

Tim. C. Claypole.

ollow Manufacturers Maintenance 'roce(ures

3.3

23.3

G3.3

H3.3

L3.3

3.3

Q3.3

K3.3

6one -ome Procedures

precisely

Do more

Maintenance -ystem All -heet fed


80/83

Tim. C. Claypole.

Replace 'arts

323

G3H3

L33Q3

K3F3

3233

Maintenance

-ystem

All

=hen brea&s

Output declines

Inspection

-upplier recommended


81/83

Tim. C. Claypole.

n or!er of most

importance

3

23

G3

H3

L3

3

Q3

K3

F3

3

233

Partofproduction

Publishchec&lists

-tandardproced

ure

Topdonpro

rity

-tafftrainingNto

ols

(.ternalsuppliers

In)ol)edepartme

nts

Matchtas&stos&ill

Monitor

JPI

-toc&&eyparts

5ery lo

%o

*igh

5ery *igh

Matching tas&s

to s&ill le)el 4

important


82/83

Tim. C. Claypole.

Top priorities for maintenance

Maintenance as an integrated acti)ity Plan as part of production

Top don priority

Management -ystem Publish chec& lists

-tandard procedures

Operator In)ol)ed Maintenance +OIM, -taff training and tools

Matching tas&s to s&ill le)els


83/83

-uccessful Maintenance Programme

Maintenance as an integrated acti)ity Dri)en by need to impro)e hole process

Management -ystem (nsure e all use the best method

Operator In)ol)ed Maintenance +OIM,

Commitment and in)ol)ement from top tobottom

Pt3 Maintenance 11

Documents

Transcript of Pt3 Maintenance 11