11-C3-Applicability of Process Control Techniques in PET Strapping Production Process-Calis_Firat_Senvar_Turgut

8/12/2019 11-C3-Applicability of Process Control Techniques in PET Strapping Production Process-Calis_Firat_Senvar_Turgut

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Applicability of Process Control Techniques inPET Strapping Production Process

Banu al

Banu Tuba Turgut

!le" #en$ar

Prof% &r% S%'"it ()tay *rat

+ar"ara ,ni$ersity-

*aculty of Engineering-

&epart"ent of .ndustrial Engineering


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Content

Overview Literature Summary Process Control Techniques Applied Studies and Findings

PET Strapping Production Process ata Collection and Preparation

Findings Conclusions and !ecommendations


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($er$ie/

The concept o# applica$ility o# ProcessControl Techniques %PCTs& to PET%Polyethylene terephthalate& strappingproduction process is presented $y using 'istograms Control charts Process capa$ility

#or #our main CT(s %$rea)ing strength* width*thic)ness* and total weight&


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SPC 0Statistical Process Control1

SPC is a well,esta$lished procedure in which data iscollected* organi-ed* analy-ed and interpreted so thata process can $e maintained at its present level o#quality or improved to a higher level o# quality.

SPC involves using statistical techniques to identi#ysource o# variation to improve per#ormance andquality simultaneously.


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Process control #ocuses on reducing the processvaria$ility to achieve the potential $ene#its coming alongwith process improvements

The aim o# process control is to )eep )ey processoperating parameters within narrow intervals and tostreamline the system $y minimi-ing the occurrence o#quality related pro$lems.

There are many ways to implement process control. PCTsgive the advantages o# monitoring the production

processes and maintaining proper #eed$ac) controlad0ustment.

Process Control


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Typical Process Control Techniques

2ey monitoring and investigating tools are given $elow3

'istograms Control Charts

Chec) Sheets Pareto Charts Cause and E##ect iagrams e#ect Concentration iagrams

Scatter iagrams

4n this study* mainly histograms and control charts are used.


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2istogra" 0continued1

Trans#orming data is the remedy o# dealing with thispro$lem.

8y this way* data are converted into trans#ormed metric so

that they have 6ormal istri$ution appearance.

There are use#ul graphical and analytical approaches #ortrans#orming the data.

4n this study log9* 9" and 1:9 tran#ormations were used.


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Control Charts Control charts are tools used to determine whether a manu#acturing

or $usiness process is in a state o# statistical control or not.

These charts consist o# a centre line %CL& which is the sample grandmean %average o# averages& and upper and lower control limits %


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Control Charts

4# a control chart indicates that the process is currently under control*

then it can $e used with con#idence to predict the #uture per#ormanceo# the process.

4# the chart indicates that the process $eing monitored is not incontrol* the pattern it reveals can help to determine the source o#variation to $e eliminated in order to $ring the process $ac) into

control.


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Control Charts 0continued1

3hy ,se Control Charts4 ?onitor process variation over time i##erentiate $etween assigna$le and common cause

variation

Assess e##ectiveness o# changes Communicate process per#ormance ?onitor process mean and varia$ility o# the process

together @


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Control Charts 0continued1


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Process Capability 0PC1

PC deals with the uni#ormity o# the process.

Daria$ility o# CT(s in the process is a measure o# theuni#ormity o# the output.

PC study #requently "easures#unctional parameters orCT(s on the product.

PC does not "easurethe process itsel#.


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5iterature Su""ary 6

Author- 7ear 7ear Sector Type of Control

Chart

8igel P% 9rigg- :eannette &aly and+ar;orie Ste/art

6


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5iterature Su""ary

Author- 7ear 7ear Sector Type of Control

Chart

:ianGin @oger :iao H Petri T% 2elo 8ylon *iberProduction

C,S,+- +5?C,S,+

Eleni +% S"etia- &e"etrios E%orona)isb- Spyridon % 9olfinopoulosa

I 3ater toGicity E3+A- C,S,+

ang- 5ee- Seong- 2a/)ins I Clinical Che"istryCJ 0Coefficient of

Jariation1

Jahid A"ir!adeh- +ashaallah +ashinchi-Abbas Parcha"i

?Bar- s


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Applied Studies and *indings

PET Strapping ProcessesPET Strapping $ecomes more an more

popular day $y day $ecause o# the advantagesversus steel hoop. As compared to steel hoops*

PET strapping tapes meanwhile o##er a range o#considera$le $ene#its3

The sta$ility o# PET tapes is compara$le to that steel hoops ue to its higher elasticity* the PET tape does not damage

the edges o# the goods pac)ed. The ris) o# in0ury in considera$ly lower than that steel

hoops Less e9pensive than steel hoops.

17


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Applied Studies and *indings

*ir"Ms Profile 4mplementation is done in Polipa)

Plastic Pac)aging San. Ltd ti which

has $een esta$lished in 1=;5* andstarted to produce PP strapping* since">>+ Company started to produce PETstrapping.


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Applied Studies and *indings Cont%

Selected product to analy-e is 1"mm>.7>mm Pet Strapping that is produce$y using twin,screw technology that is a

computer $ased control and dataacquisition system. 8y using this technology all process

parameters are controlled andmonitored via '?4 %'uman:?achine4nter#ace& so#tware


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Process *lo/ of PETProduction process o#

the 1"mm Pet strapping can $ede#ine as The material #la)esare melted in e9truder* then#iltered and shape in die intoseveral straps emerging side $y

side.

A#ter $rie# cooling in thewater $ath* the straps undergosecondary processing in theproduction line namely several

annealing and streching stagesto provide them the requiredtensile strength. Producedstraps winding $y usingwrappings.

">


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For PET Strapping production process* / main CT(s asthe product varia$les3

$rea)ing strength* width* thic)ness* total weight %gram:mt&

are analysed separately in order to identi#y the status o#the o$tained data whether they are in statistical control ornot.


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&ata Collection and Preparation

">= o$servations >1.>.">>= G 1".";.">>= ata

Strength ma9,min daily idth ma9,min daily Thic)ness ma9,min daily

Total weight %Hram:mt& daily


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&ata EGa"ination

'istograms Assesing 6ormality, Trans#ormations Control Charts

Process Capa$ility


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2istogra" of t hic)ness "in


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Transfor"ations

1/x x2 5og0G1

$rea)ingIstrengthImin Very Narrow Very Narrow

$rea)ingIstrengthIma9 Very Narrow Very Narrow

widthImin Continuity - Continuity - Continuity -

widthIma9 Continuity - Continuity - Continuity -

thic)nessImin Continuity - Continuity - Continuity -

thic)nessIma9 Veri Narrow Narrow Very Narrow

totalIweight %gram:mt& Right Skewe Narrow
http://var/www/apps/conversion/tmp/scratch_3/Histograms-1%200ver%20x.dochttp://var/www/apps/conversion/tmp/scratch_3/Histograms-x2.dochttp://var/www/apps/conversion/tmp/scratch_3/Histograms-log.dochttp://var/www/apps/conversion/tmp/scratch_3/Histograms-log.dochttp://var/www/apps/conversion/tmp/scratch_3/Histograms-x2.dochttp://var/www/apps/conversion/tmp/scratch_3/Histograms-1%200ver%20x.doc


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Applied Studies and *indings Cont%J At the begining of the study- the control charts are prepared by using +initab

soft/are- /hich are gi$en belo/%

+1


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J A#ter graphing control charts* outliers aredetermined and related data are eliminatedand control charts are drawn with modi#ieddata.

J For the 8rea)ing Strength data* three timeselimination is used #or Thic)ness and idthdata* two times elimination is done and#inally #or Total eight %Hram:?t& data onlyone elimination is implemented

J 6ew control charts are as #ollow3


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J Last control charts are analy-ed $y using Kone !uleswhich areG One or more points outside o# the control limitsG Two o# three consecutive points outside the two sigma

warning limits $ut still inside the control limitsG Four o# #ive consecutive points $eyond the one sigma limitsG A run o# eight consecutive points on one side o# the

centerlineG Si9 points in a row steadily increasing or decreasingG Fi#teen points in a row in -one C%$oth a$ove and $elow the

centerline&

G Fourteen points in a row alternating up and downG Eight points in a row on $oth sides o# the centerline with nonin -one C

G An unusual or non random pattern in the dataG One or more points near a warning or control limit


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Process Capability 0PC1

PC deals with the uni#ormity o# the process.

Daria$ility o# CT(s in the process is a measure o# theuni#ormity o# the output.

PC study #requently "easures#unctional parameters orCT(s on the product.

PC does not "easurethe process itsel#.


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9eneral @eco""endations for Processes

For an e9isting process* the Cp is a$ove the recommended minimum%1.++&

For a new process* the Cp is a$ove the recommended minimum%1.>&

For an e9isting critical process %sa#ety* strength&* the Cp is a$ove therecommended minimum %1.>&

For a new critical process %sa#ety* strength&* the Cp is a$ove the

recommended minimum %1.57&

@eference Jalues


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Conclusions and@eco""endations

Apart #rom histograms and control charts* other PCTs can$e applied to control the process and improve productuni#ormity.

4n this study log9* 9" and 1:9 tran#ormations were used. 4tis reali-ed that assumption o# normal distri$ution is valid.So original data is used without trans#ormation.

A#ter monitoring the process* causes o# out,o#,controlsignals can $e determined and eliminated so thatimprovement can $e attained #or overall processper#ormance.


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4mportant signals #or each parameters areo$served as For Total weight %Hram,?t& "* +* = and 1>* For 8rea)ing Strength 1* + and 1>* For Thic)ness 1* + and 1>* For idth data + and 1>.

?ost o# the out,o#,control signals are detected#or the third and tenth rules.


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For the #irm* a pac)age program can $e permanently used to

monitor the process and

-one rule + and rule 1> may $e investigated in detail.

4n #act* monitoring only the #our CT(s o# a product isnot seen su##icient to de#ine and improve a process.


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Controlling manu#acturing processes during operationis also suggested in order to satis#y customer

requirements.

The $ene#its derived #rom SPC in the areas o# reducedinternal and e9ternal #ailures should o##set any

additional costs incurred #rom sample collection* testingand data analysis.


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@eferences

?ontgomery* ouglas C.* ">>=. Statistical (uality Control, A ?odern 4ntroduction* Mohn

iley N Sons* 4nc. 2ee,hung Lai* T.C. Edwin Cheng* ">>. E##ects o# quality management and mar)eting on

organi-ational per#ormance* Mournal o# 8usiness !esearch ; %//5G /5&.

Arditi * avid and Hunaydin* ' ?urat* 1==7. Total quality management in the constructionprocess. 4nternational Mournal o# Pro0ect ?anagement Dol. 1* 6o. /* pp. "+,"/+.

Den)atesan * H.* ">>+. Process control o# product quality. 4SA Transactions Dol. /" pp.5+1G5/1.

Dollmer * T.* 8orcherding * 2.* 'ellriegel * H.* Pen-horn * !.,.* ">>>. Process control undersa#ety aspects. Fusion Engineering and esign /; 7G51.

Liu * .* 'e* K.* Shu* L.* u* K.* ">>=. Statistical computation and analyses #or attri$uteevents. Computational Statistics and ata Analysis. Dol +* pp. +/1",+/".

Khao* C.* Khao* .* Su* '.* 'uang* 8.* ">>=. Economic per#ormance assessment o#advanced process control with L(H $enchmar)ing. Mournal o# Process Control 1= 7G

5=. Smeti* E.?.* Thanasoulias* 6.C.* 2ousouris* L.P.* T-oumer)as* P.C.* ">>7. An approach #or

the application o# statistical proces.s control techniques #or quality improvement o# treatedwater. esalination "1+ "7+G";1


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@eferences Hrigg* 6. P* aly* M. Stewart* ?.* 1==;. Case study3 the use o# statistical process control in

#ish product pac)aging. FoodC ontrol* =:5 ";=,"=7 Chen* H.* Cheng* S. .* 1==;. The e9act u chart can $e o$tained using simple

ad0ustments. Statistics N Pro$a$ility Letters +7 +7,+5.

!i$eiroa* L. ?. ?.* Ca$ral M. A. S.* 1===. The use and misuse o# statistical tools. Mournal o#?aterials Processing Technology =",=+ ";;,"=".

Chang* T. C.* Han* F. F.* 1===. Application o# 9 control chart with modi#ied limits in processcontrol. (uality and relia$ility engineering international 13 +G+5".

Sri)aeo* 2.* Furst M. E.* Ashton* M.* ">>. Characteri-ation o# wheat,$ased $iscuit coo)ingprocess $y statistical process control techniques. Food Control 15 +>=G+17.

8urli)ows)a* ?. .* ">>. (uality estimation o# process with usage control charts type ,!and quality capa$ility o# process Cp* Cp). Mournal o# ?aterials Processing Technology15"G15+ 7+5G7/+.

Cha)ra$orty* S.* Tah* .* ">>5. !eal time statistical process advisor #or e##ective quality

control. ecision Support Systems /" 7>>G 711


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@eferences

?otorcu* A. !.* HQllQ* A.* ">>5. Statistical process control in machining* a case study #or

machine tool capa$ility and process capa$ility. ?aterials and esign "7 +5/G+7". Miao* M. !. N 'elo* Petri T. * ">>5. Optimi-ation design o# a C


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11-C3-Applicability of Process Control Techniques in PET Strapping Production Process-Calis_Firat_Senvar_Turgut