zmanj{anje stro{kov v odpremi z uporabo metodologije {est sigm

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Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs

Skupina za izbolj�anje kakovosti in produktivnosti v podjetju TPV Johnson Controls, ki izdelujeavtomobilske sede�e za Renault Clio, je izpeljala projekt izbolj�anja razmer pri odpremi sede�ev. Povod za taprojekt je bila majhna zasedenost delavcev v odpremi, �e zlasti voznika tovornjaka. S sistematiènim prijemomin timskim delom smo dosegli ugodne rezultate v obliki ukinitve enega delovnega mesta (enega delavca naizmeno) s prerazporeditvijo del in nalog na druga delovna mesta v odpremi in s tem dviga produktivnosti nazadovoljivo raven.

Tako je uporaba metodologije �est sigm pri izvedbi tega projekta prispevala k precej�njim prihrankomin izbolj�anju uspe�nosti poslovanja.© 2004 Strojni�ki vestnik. Vse pravice pridr�ane.(Kljuène besede: metodologija �est sigm, zmanj�evanje stro�kov, uèinkovitost dela)

The team responsible for improving quality and productivity at TPV Johnson Controls, a companyproducing car seats for the Renault Clio, carried out a project to improve the efficiency of its shippingprocedure. The reason for the project was the low labour efficiency in the shipping area, especially that of thetruck driver. A systematic approach and teamwork abilities contributed to favourable results in the form of alay-off of one workstation (one worker per shift) through a re-distribution of work assignments to othershipping workstations, and to an increase in efficiency to a satisfactory level.

The use of Six Sigma methodology in this project has meant considerable savings for the companyand an improvement in its business performance.© 2004 Journal of Mechanical Engineering. All rights reserved.(Keywords: Six Sigma metodology, costs savings, labour efficiency)

Reducing the Costs of Shipping Automotive Products by Imple-menting a Six Sigma Methodology

Mirko Sokovi} - Miran Jure~i~ - Andrej Kramar

© Strojni{ki vestnik 50(2004)4,219-228ISSN 0039-2480UDK 658.512.4:658.562Kratki znanstveni prispevek (1.03)

© Journal of Mechanical Engineering 50(2004)4,219-228 ISSN 0039-2480

UDC 658.512.4:658.562Short scientific paper (1.03)

Zmanj{anje stro{kov v odpremi z uporabometodologije {est sigm

0 UVOD

Postopek, ki se imenuje �est sigm, jerelativno nov in se uporablja pri zagotavljanjukakovosti in vodenju kakovosti s poudarkom nastalnem izbolj�anju kakovosti. Postopek izbolj�av seuvaja skozi sistematièno projektno usmerjenometodologijo �definiraj, izmeri, analiziraj, izbolj�aj innadziraj� DIAIN - DMAIC). Raven sigm poka�emo�nosti za nekakovosten izdelek. V primeru ravni�est sigm so mo�nosti za neustrezen izdelek enake3,4 kosov na milijon. Doseganje ravni kakovosti �estsigm vkljuèuje vodstvo, infrastrukturo, ustreznaorodja in metode, pri èemer kakovost postaja delskupnega naèrta poslovanja organizacije ([1] do [5]).

1 PROJEKT �EST SIGM

1.1 Faza - Definiraj

- Opredelitev problema

0 INTRODUCTION

Six Sigma is a new, emerging approach toquality assurance and quality management with theemphasis on continuous quality improvement.Process improvements are implemented in asystematic manner through DMAIC methodology:Define, Measure, Analyse, Improve, and Control. TheSigma level indicates the possibility of a defectiveproduct. In the case of a Six Sigma level, the chanceof a defective product is equal to 3.4 ppm. Achievinga Six Sigma quality level involves leadership,infrastructure, appropriate tools and methods, and inaddition, quality has to become a part of corporatebusiness plan ([1] to [5]).

1 SIX SIGMA PROJECT

1.1 Define Phase

- Problem Statement & Quantification

04-4stran 220


V oddelku odpreme je 10 delavcev (pet v vsaki izmeni):voznik vilièarja � lanser sestavnih delov, odpremnikSS (sprednjih sede�ev), odpremnik ZS (zadnjihsede�ev), voznik vilièarja � odpremnik sede�nihgarnitur in voznik tovornjaka. Odpremnika sede�evnalagata sede�e na palete za odpremo (najprejsprednje in nato �e zadnje sede�e). Voznik vilièarja �odpremnik odva�a palete s sede�nimi garniturami vzaèasno skladi�èe in jih potem po potrebi natovarjana tovornjak. Voznik tovornjaka dostavlja sede�negarniture odjemalcu (sl. 1). Zasedenost delavcev naodpremi je nezadovoljiva (manj�a od 61 %).

- Cilj projektaAnalizirati zasedenost delavcev v oddelku odpremeter ukinitev enega voznika vilièarja na izmeno.

- Upo�tevani prihranki projektaUkinitev voznika vilièarja � odpremnika na izmeno/na leto: $ 18 000Skupni letni prihranek (dve izmeni): $ 36 000

There are 10 workers in the shipping area (five pershift): forklift driver-feeder, shipping operator FS(front seats), shipping operator RS (rear seats),forklift driver and truck driver. The shippingoperators load the seats onto the pallets forshipping (first FS, then RS), the forklift driver movesthe pallets with seat sets in the area between theshipping line and the temporary warehouse, andthen loads them onto the truck. The truck driverdelivers the seat sets to the customer, Figure 1.The labour efficiency is unsatisfactory (less than61 %).

- Project ObjectiveAnalyse the labour efficiency in the shipping areaand consequently lay-off one forklift driver per shift.

- Project Saving ForecastOne forklift driver lay-off per shift/per year:$ 18 000Saving per year (two shifts): $ 36 000

Sl. 1. Opredelitev problema v oddelku odpreme [6]Fig. 1. Problem statement in the shipping area [6]

Sl. 2. Zaèetek in konec (meji) postopka [6]Fig. 2. Process Start & End Points [6]

Voznik vilièarja - odpremnik

Forklift driver

Odpremnik zadnjih sede�ev / Shipping

operator RS (rear seats)

Odpremnik sprednjihsede�ev / Shipping

operator FS (front seats)

Palete s sede�nimi garniturami / Pallets

with seat sets

Prièetek postopkaIzdelani sprednji in zadnji sede�iProcess start

Front and rear sits

DM 12 - Spr. sede�iDM 55 - Zad. sede�iWS 12 - Front seatsWS 55 - Rear seats

Zasedenost voznika kamionaEfficiency of the truck driver

Zasedenost odpremnikov sprednjihin zadnjih sede�ev in vilièaristov-odpremnikovEfficiency of forklift drivers-feeders, shipping operators for FS and RS, forklift drivers

Konec postopkaOdprema sede�ev kupcuProcess end

Seats delivered to the customer

PostopekNalaganje na paleto in paleto sede�ev na kamion ter lansiranjemateriala na DMIzdelani sprednji in zadnji sede�iProcess

Feeding the line with components, loading FS and RS onto the pallets and loading the truck

04-4stran 221


- Te�i�èe projekta in Meje poteka postopkaKaj naj bi merili: Zasedenost delavcev v oddelkuodpreme. Zaèetek in konec (meji) postopka stapodani na sliki 2.

- Slika poteka postopkaSlika 3 prikazuje �Sliko poteka postopka� zadejavnosti v oddelku odpreme.

1.2 Faza - Izmeri

- Diagram ponovljivosti meritevMerjeno je bilo: nalaganje palet z garnituramisede�ev ene na drugo, prevoz z odpremne proge vvmesno skladi�èe in prevoz prazne palete izvmesnega skladi�èa na odpremno progo.Analiza ponovljivosti (sl. 4) ka�e, da je izbran naèinmerjenja ustrezen. Variiranje med veèkratnimiponovitvami meritev za posamezne dejavnosti jemajhno.

- Test normalnostiTest normalnosti podaja ugotovitev, ali lahko skloppodatkov obravnavamo kot normalno porazdeljenepodatke. Vrednost P je namreè verjetnost, da dobimonatanèen vzorec, èe so podatki normalnoporazdeljeni. Sledili smo pravilu: a) Vrednost P < a: podatki niso normalno

porazdeljeni.b) Vrednost P > a: podatki so normalno porazdeljeni.

- Project Focus & Process Boundary MapWhat was measured: Labour efficiency in theshipping area. The process start and end pointsare shown in Figure 2.

- Process MapFigure 3 shows the �Process Map� for the activitiesin the shipping area.

1.2 Measure Phase

- �Total Gage R&R� � graphThe measured operations were as follows: stackingof full pallets, delivery from the shipping line into thetemporary warehouse, and delivery of empty palletsfrom the temporary warehouse onto the shipping line.The Gage R&R analyses (Fig. 4) show that threeoperators were measuring consistently. Thevariation between multiple measurements for eachindividual part is small.

- Normality TestThe normality test shows whether a collection ofdata can be treated as normally distributed data.The P-value is the probability of getting an accuratepattern if the data are normally distributed. Wefollow the principle: a) P-Value < a: The data are not normally

distributed.b) P-Value > a: The data are normally distributed.

Sl. 3. Slika poteka postopka ([6] in [7])Fig. 3. Process Map ([6] and [7])

Voznik vilièarjaForklift driver

Voznik vilièarjaForklift driver

Odpremnik ZSShipping

operator RS

Odpremnik SSShipping

operator FS

Voznik kamionaTruck driver

Voznik vilièarja - lanser

Forklift driver- feeder

-

04-4stran 222


- �Diagram normalnosti verjetnosti in x , R-karta�.Oba testa za vseh 10 delavcev v oddelku odpremeka�eta, da sklop podatkov lahko obravnavamo kotnormalno porazdeljenega in da so merjeni procesistabilni, vendar neuèinkoviti. Primer �testanormalnosti� za voznika vilièarja � odpremnika vizmeni A je prikazan na sliki 5.

- Diagram zasedenosti delavcev v oddelkuodpremeDiagram zasedenosti na sliki 6 ka�e, da sta voznikavilièarja � odpremnika uèinkovita le 55 %, voznik

- �Normality Probability Plots�&�I and MR Chart�,for all 10 workers in the shipping area show that acollection of data can be treated as normallydistributed data and that the measured processesare stable, but of low efficiency. An example of the�Normality Test� for the forklift driver in the A shiftis shown in Figure 5.

- �Box plots graph� - Labour efficiency in the shippingareaThe Box plots graph (Fig. 6) shows that the twoforklift drivers are only 55 % efficient and the truck

Sl. 4. Analiza ponovljivostiFig. 4. The Gage R&R analyses

000

888 777 666 555 444 333 222 111 000

OOO ppp eee rrr aaa ttt eee rrr 333 OOO ppp eee rrr aaa ttt eee rrr 222 OOO ppp eee rrr aaa ttt eee rrr 111 XXX bbb aaa rrr CCC hhh aaa rrr ttt bbb yyy OOO ppp eee rrr aaa ttt ooo rrr

MMM eee aaa nnn === 222 ... 777 111 666 UUU CCC LLL === 222 ... 999 777 888 LLL CCC LLL === 222 ... 444 555 333

000

000 ... 555 000 ... 444 000 ... 333 000 ... 222 000 ... 111 000 ... 000

OOO ppp eee rrr aaa ttt eee rrr 333 OOO ppp eee rrr aaa ttt eee rrr 222 OOO ppp eee rrr aaa ttt eee rrr 111 RRR CCC hhh aaa rrr ttt bbb yyy OOO ppp eee rrr aaa ttt ooo rrr

RRR === 000 ... 111 333 999 777

UUU CCC LLL === 000 ... 444 555 666 333

LLL CCC LLL === 000

111 000 999 888 777 666 555 444 333 222 111

777 666 555 444 333 222 111

PPP aaa rrr ttt

OOO ppp eee rrr aaa ttt eee rrr OOO ppp eee rrr aaa ttt ooo rrr *** PPP aaa rrr ttt III nnn ttt eee rrr aaa ccc ttt iii ooo nnn

AAAvvveee

aaagggeee

OOO ppp eee rrr aaa ttt eee rrr 111 OOO ppp eee rrr aaa ttt eee rrr 222 OOO ppp eee rrr aaa ttt eee rrr 333

OOO ppp eee rrr aaa ttt eee rrr 333 OOO ppp eee rrr aaa ttt eee rrr 222 OOO ppp eee rrr aaa ttt eee rrr 111

777 666 555 444 333 222 111

BBB yyy OOO ppp eee rrr aaa ttt ooo rrr 111 000 999 888 777 666 555 444 333 222 111

777 666 555 444 333 222 111

PPP aaa rrr ttt

BBB yyy PPP aaa rrr ttt %%% CCC ooo nnn ttt rrr iii bbb uuu ttt iii ooo nnn %%% SSS ttt uuu ddd yyy VVV aaa rrr

PPP aaa rrr ttt --- ttt ooo --- PPP aaa rrr ttt RRR eee ppp rrr ooo ddd RRR eee ppp eee aaa ttt GGG aaa ggg eee RRR &&& RRR

111 000 000

555 000

000

CCC ooo mmm ppp ooo nnn eee nnn ttt sss ooo fff VVV aaa rrr iii aaa ttt iii ooo nnn

Sl. 5. �Test normalnosti� za voznika vilièarja � odpremnika v izmeni AFig. 5. �Normality Test� for the forklift driver in the A shifts

St. dev / StdDev �tudij var. / Study Var %�tudij var. / %Study VarVir / Source (SD) (5.15*SD) (%SV)Celotna ponov. meritveTotal Gage R&R

0,09272 0,4775 4,03

PonovljivostRepeatability

0,09143 0,4709 3,97

ReproduktivnostReproducibility

0,01541 0,0794 0,67

DelavecOperator

0,01541 0,0794 0,67

Kos proto kosuPart-To-Part

2,30162 11,8533 99,92

Celotna variacijaTotal Variation

2,30349 11,8630 100,00

Average: 55.3143

StDev: 0.459658

N: 21

Anderson-Darling Normality Test

A-Squared: 0.426

P-Value: 0.286

54.6 55.1 55.6 56.1

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I and MR Chart x in R-karta / I and MR chartDiagram normalnosti verjetnosti /Normal probability plot

verj

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P-Vrednost > (0,05)a

Podatki so normalno porazdeljeni

P-Value > (0,05)a

The data are normally distributed

04-4stran 223


tovornjaka pa samo 27 %. Torej, je bil cilj timapoiskati poti za bistveno poveèanje uèinkovitostidela ter uporabo notranjih rezerv v oddelkuodpreme in nazadnje ukiniti delovno mesto dvehvoznikov vilièarja (v vsaki izmeni enega).

1.3 Faza - Analiziraj

- �Testiranje domneve� uèinkovitosti za posameznadelovna mesta v izmenah A in BV podporo doseganju ciljev smo izvedli �testiranjedomneve� uèinkovitosti dela za vsa delovna mestav odpremi, v izmenah A in B.Testi ka�ejo, da ni bilo razlike pri uèinkovitostienakih delovnih mest v obeh izmenah.

- �testiranje domneve� uèinkovitosti za A in Bvoznika vilièarja � odpremnika

driver�s efficiency is only 27 %. Thus, the target ofthe team is to find ways to substantially increasethe efficiency and make use of internal reserves inthe shipping area and consequently lay-off twoforklift drivers.

1.3 Analyze Phase

- �Hypothesis tests�of the efficiency in A and B shiftson all workstationsTo support the setting of targets we made�Hypothesis tests� of the labour efficiency in the Aand B shifts on all workstations in the shipping area.The tests showed that there was no difference in theefficiency of the same workstations in the two shifts.

- �hypothesis test� of the efficiency for A and Bforklift drivers (FLDs)

Sl. 6. Diagram zasedenosti delavcevFig. 6. Box plots graph of the efficiency of operators

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Delavci / Operators

Nièelna domneva - Ho: µ A izmena = µ B izmenaNull Hypothesis - Ho: µ A shift = µ B shiftNasprotna domneva - H1: µ A izmena # µ B izmenaAlternative Hypothesis - H1: µ A shift # µ B shift Dvo-vzorèni T-test in CI: A-% voznik vilièarja in B-% voznik vilièarjaTwo-Sample T-Test and CI: A-% FLD in B-% FLD

Sr. vr. dt.drv. SE sr.vr.N Mean StDev SE Mean

A - % voznik vilièarjaA - % forklift driver

21 55,314 0,460 0,10

B - % voznik vilièarjaB - % forklift driver

21 55,419 0,446 0,097

Razlika / Difference = mu A-% voznik vil. / FLD - mu B-% voznik vil. / FLDOcena za razliko / Estimate for difference: -0.105 (razlika od srednje vrednosti / difference of mean value)95% CI za razliko / for difference: (-0,387; 0,178)T-test razlike / T-Test of diff. = 0 (vs not =): T-vrednost / value = -0.75 P-vrednost / value = 0,458 DF = 39

P-Vrednost > 0,05a

Sprejmemo "nièelno domnevo"ni razlike med zasedenostjo voznika vilièarja A in B.

P-Value > 0.05a

�Null Hypothesis� accepted no difference between the efficiency of A and B forklift drivers.

04-4stran 224


- �Testiranje domneve - ANOVA�: Uèinkovitostvoznikov vilièarja � odpremnikov A in B ter voznikatovornjaka

Iz opravljenega izraèuna je razvidno, da ninobene razlike v zasedenosti med voznikoma vilièarja� odpremnikoma izmene A in B, kar pa ne velja zarazmerje med voznikom tovornjaka in voznikom vilièarja� odpremnikom izmene A in tudi ne za razmerje medvoznikom tovornjaka in vilièaristom-odpremnikomizmene B (obe vrednosti sta pozitivni razliki).

Vse opravljene raziskave (Testiranje domneve,Testiranje domneve - ANOVA, Diagram zasedenosti, Analizeizvora in vpliva napak (AIVP)) so dokazale, da so na odpremidelovna mesta, ki lahko prevzamejo doloèena dela in nalogeod voznika vilièarja � odpremnika (v obeh izmenah).

1.4 Faza - Izbolj�aj

- Akcija za doseganje ciljaSkupina je razporedila dela in naloge voznikavilièarja � odpremnika izmen A in B na druga delovnamesta glede na rezultate analize njihove zasedenosti(sl. 7).

- �Testiranje domneve� za voznika vilièarja / voznikatovornjaka (novo stanje)Glede na rezultate simulacije se je skupina odloèila,da voznik tovornjaka prevzame dodatna dela(zamenjavo palet, nalaganje tovornjaka inzamenjavo akumulatorja na vilièarju). Za statistièno

- �Hypothesis test - ANOVA�: Efficiency of A and Bforklift drivers and the truck driver

The calculation shows that there is no dif-ference between the efficiencies of the A and B fork-lift drivers, but this does not hold true for the ratiobetween the truck driver�s efficiency and that of theA forklift driver, in the same way as it is not true forthe ratio between the truck driver and the B forkliftdriver (both values are positive � difference).

All our researches (Hypothesis test,Hypothesis test - ANOVA, Box Plots graphs, Failuremode and effect analysis (FMEA)) so far prove thatthere are workstations in the shipping area that couldtake over some tasks from the forklift drivers (bothshifts).

1.4 Improve Phase

- Action to achieve the targetWith the help of the team we succeeded in distrib-uting the work assignments of the A and B forkliftdrivers to other workstations on the basis of theirefficiency analysis (Fig. 7).

- �Hypothesis test� for forklift driver - FLD / truckdriver - TD (new situation)Based on the simulations the team decided thatthe truck driver should take on additional tasks(changing of pallets, loading the truck andchanging the battery on the forklift). To

Nièelna domneva - Ho: µ A voznik vilièarja = µ B voznik vilièarja = µ voznik tovornjakaNull Hypothesis - Ho: µ A forklift driver = µ B forklift driver = µ truck driverNasprotna domneva - H1: µ A voznik vilièarja # µ B voznik vilièarja # µ voznik tovornjakaAlternative Hypothesis - H1: µ A forklift driver # µ B forklift driver # µ truck driver »Analiza variance« za vse podatke (za potrditev razlike) / »Analysis of Variance« for all data (to confirm the difference) Vir / Source DF SS MS F P Subs 2 11428,69 5714,34 3,0 0,000 Napaka / Error 6 0 11,33 0,19 Celotno / Total 6 2 11440,01

N Sr.vr. / Mean StDevA - % Voznik vilièarjaA - % Forklift driver 21 55,314 0,460

B - % Voznik vilièarjaB - % Forklift driver 21 55,419 0,446Voznik tovornjakaTruck driver 21 26,795 0,396

P < 0.05; Zavrnemo

"nièelno domnevo"

P < 0.05; Null hypothesis rejected

Nièelna domneva - Ho: µ voznik vilièarja = µ voznik tovornjakaNull Hypothesis - Ho: µ forklift driver = µ truck driverNasprotna domneva - H

1: µ voznik vilièarja # µ B voznik tovornjaka

Alternative Hypothesis - H1:

µ forklift driver # µ B truck driverDvo-vzorèni T-test za voznika vilièarja proti vozniku tovornjaka / Two-sample T for FLD CH. PALLET vs TD CH. PALLET

M sr.vr. / Mean StDev SE sr.vr. / Meanvoznik vilièarjaFLD CH. PALLET 3 0 6,7870 0,0223 0,0041

voznik tovornjakaTD CH. PALLET 3 0 6,8003 0,0243 0,0044

Razlika / Difference = mu voznik vilièarja / FLD CH. PALLET - mu voznik tovornjaka / TD CH. PALLETOcena za razliko / Estimate for difference: -0,0133395% CI za razliko / for difference: (-0,02539; -0,00128)T-Test razlike / of difference = 0 (vs not =): T-vrednost / Value = -2.21 P-vrednost / Value = 0,031 DF = 57

P < 0,05; Sprejmemo "Nièelno hipotezo"P < 0.05; Fail to reject the Null Hypothesis

04-4stran 225


Sl. 7. Porazdelitev delovnih nalog voznikov vilièarjev � odpremnikov A in B

Fig. 7. Distribution of the work assignments of the A and B forklift drivers

VILIÈARIST-ODPREMNIK Sr. vr. VOZNIK TOVORNJAKA Sr. vr. = 26,80%

Èaka na vilièarju A shift = 55,31% Vozi tovornjak s polnimi paletami kupcu

Menjava palete za odpremo B shift = 55,42% Dodana prevzeta delaNatovarja tovornjak Menjava palete za odpremo

Raztovarja tovornjak Natovarja tovornjakMenjava akumulator na vilièarju Raztovarja tovornjakLansira sestavna dele na delovna mesta Menjava akumulator na vilièarjuLansira ostali material na delovna mestaOdva�a prazne embala�eOdva�a smeti na deponijo

Odpira embala�o

Lansira vzglavnike zadnjih naslonov na DM

ODPREMNIK SPREDNJIH SEDE�EV Sr. vr. = 78,86% Dodana prevzeta delaPrena�a sede�e z linije sest.na odpremno linijo Knji�i SELEX etikete v informacijski sistem

ODPREMNIK ZADNJIH SEDE�EV Sr. vr. = 74,90 % Dodana prevzeta delaPrena�a sede�e z linije sest.na odpremno linijo Menjava palet za odpremoKnji�i SELEX etikete v informacijski sistem Lansira vzglavnike zadnjih naslonov na DM

VILIÈARIST-LANSER Sr. vr. Dodana prevzeta delaLansira sestavna dele na delovna mesta A izmena = 82,7 % Lansira sestavna dele na delovna mestaOdpira embala�o B izmena = 82,8 % Lansira ostali material na delovna mestaNalaga in lansira vodila sede�ev Odva�a prazne embala�eLansira podsklope "APA" Odva�a smeti na deponijo

Lansira blazine sede�ev Odpira embala�oOdva�a prazne embala�eOdva�a smeti na deponijoÈaka na vilièarju

Menjava akumulator na vilièarju

04-4stran 226


Truck driver newForklift driver

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Forklift driver Truck driver new

0,10

0,05

0,00

Sam

ple

Rang

e

R=0,02867

UCL=0,09366

LCL=0

Forklift driver Truck driver new

driver and Truck driver new

Xbar/R Chart comparison between Forklift

x / R-karta: primerjava za voznika vilièarjain voznika tovornjaka (novo stanje)

Blok diagram za voznika vilièarja invoznika tovornjaka (novo stanje)

voznik vilièarjaforklift driver

voznik tovornjaka (novo stanje)truck driver new

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dela

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potrditev upravièenosti na�e odloèitve smonaredili nove meritve in izraèune.Blok diagram in x / R-karta (sl. 8) ka�eta, da vozniktovornjaka lahko prevzame nalogo zamenjave paletod voznika vilièarja � odpremnika.

- Diagram zasedenosti delavcev v oddelku odpreme� novo stanjeDiagram na sliki 9 prikazuje poveèanje zasedenostidelavcev v oddelku odpreme, ki je posledicaprerazporeditve delovnih nalog zaradi ukinitvedelovnega mesta enega voznika vilièarja na izmeno.

1.5 Faza - Nadziraj

- � x / R-karta� za delavce v odpremiV tej fazi smo preverili stabilnost novih postopkovin poveèanje uèinkovitosti, kar ponazarja uspehprojekta (sl. 10).

statistically confirm the justification of our decisionwe made new measurements and calculations.The box plots and the Xbar/R Chart (Fig. 8) showthat the truck driver is able to take over the task ofchanging the pallets from the forklift driver.

- �Box Plots graph� for labour efficiency in theshipping area � new situationThe graph (Fig. 9) shows the increase in labourefficiency in the shipping area, which results fromthe re-distribution of work assignments due to thelay-off of one forklift driver per shift.

1.5 Control Phase

- �I and MR Charts� for shipping workersThese charts prove the stability of the newprocesses and the rise in efficiency, whichdemonstrates the success of the project (Fig. 10).

Sl. 9. Diagram zasedenosti za novo stanje v odpremiFig. 9. Box plots graph for the new situation

Sl. 8. Blok diagram in x / R-kartaFig. 8. Box Plots and Xbar/R Char

90

80

70

60

50

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30

20

Zas

eden

ost

(%)

Eff

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Voznik vilièarja AForklift driver A

Voznik vilièarja BForklift driver B

Odpremnik SS / Shipping operator FSVoznik vilièarja- lanser BForklift driver- feeder B

Voznik vilièarja- lanser AForklift driver- feeder A

Odpremnik ZS, novo stanjeShipping operator RS, new

Voznik tovornjakaTruck driver

Delavci / Operators

Voznik vilièarja - lanser, novo stanjeForklift driver - feeder, new

Voznik tovornjaka, novo stanjeTruck driver, new

UkinitevLay-off

Odpremnik ZSShipping operator RS

Odpremnik SS, novo stanje / Shipping operator FS, new

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0Subgroup 10 20 30

20

30

40

50

60

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Ind

ivid

ual V

alu

e Mean=61.64UCL=64.80

LCL=58.48

Truck driver before Truck driver after

0

1

2

3

4

Mo

vin

g R

ang

e

R=1.189

UCL=3.884

LCL=0

Truck driver before Truck driver after

I and MR Chart for Truck driver before and after

- Spremenjeni naèrt nadzoraV tej sklepni fazi metodologije DIAIN je bil razvitnaèrt nadzora, da bi zagotovili konsistentnostprocesov in izpolnitev zahtev odjemalcev.

2 SKLEP

Postopek �est sigm zahteva sistematiènostin konstruktivno delo celotne skupine. Cilj �est sigmje izbolj�ati organizacijsko uèinkovitost kakor tudiuspe�nost pri zadovoljevanju odjemalèevih potrebter resnièno oblikovanje ekonomskega blagostanjatako za odjemalca kakor dobavitelja. V analiziranemprimeru je podjetje doseglo prihranke v znesku 36.000$ na leto.

Sl. 10. x / R-karta voznika tovornjaka pred prerazporeditvijo nalog in po njejFig. 10. I and MR Chart for shipping workers

- Modified Control PlanIn this final phase of the DMAIC methodology, a controlplan was developed to ensure that the processesconsistently meet our and the customer�s requirements.

2 CONCLUSION

Six Sigma requires a systematic approachand the constructive work of the whole team. Theobjective of Six Sigma is to improve an organisation�sefficiency as well as its effectiveness in meeting thecustomer�s needs, ultimately creating economic wealthfor the customer and the provider. In the analysedcase the company achieved savings of $ 36,000 peryear.

3 LITERATURA3 REFERENCES

[1] Breyfogle III, F. W., et al. (1999) Managing Six Sigma, John Wiley & Sons, Inc., New York.[2] Fortenot, F, et al. (1994) Six Sigma in customer satisfaction, Quality Progress, No 12.[3] Pavletiæ, D., M. Sokoviæ (2002) Six Sigma: A complex quality Initiative, J. of Mech. Eng., Vol. 48, No 3.[4] N.N.: 6s Training MAIC, Johnson Controls, 2001.[5] N.N.: Interno �olanje za 6s, TPV Johnson Controls, 2001, 2002, and 2003 (in Slovene).[6] Jureèiè M., M. Sokoviæ (2003) Cost reduction in the shipping area in the company producing car seats,

Diploma thesis No. S-895, Faculty of Mechanical Engineering, University of Ljubljana (in Slovene).[7] Kramar A., M. Jureèiè M. and M. Sokoviæ (2003) Cost reduction in the shiping area using Six Sigma,

Proceedings of the 6th Int. Conf. on Management of Innovative Technologies - MIT 2003, 13-14 October2003, Piran, Slovenia, 267-274.

x in R-karta za voznika tovornjaka pred in po spremembi

voznik tovornjaka (pred)truck driver before

voznik tovornjaka (pred)truck driver before

voznik tovornjaka (potem)truck driver after

voznik tovornjaka (potem)truck driver after

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04-4stran 228


Naslova avtorjev: doc.dr. Mirko SokoviæUniverza v LjubljaniFakulteta za strojni�tvoA�kerèeva 61000 [email protected]

Miran JureèièAndrej KramarTPV Johnson Controls d.o.o.8000 Novo mesto

Prejeto: 8.1.2004

Sprejeto: 8.4.2004

Odprto za diskusijo: 1 letoReceived: Accepted: Open for discussion: 1 year

Authors�s Addresses: Doc.Dr. Mirko SokoviæUniversity of LjubljanaFaculty of Mechanical Eng.A�kerèeva 6SI-1000 Ljubljana, [email protected]

Andrej KramarMiran JureèièTPV Johnson Controls Ltd.SI-8000 Novo mesto, Slovenia

zmanj{anje stro{kov v odpremi z uporabo metodologije {est sigm

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