© Strojni{ki vestnik 50(2004)4,219-228 © Journal of Mechanical Engineering 50(2004)4,219-228 ISSN 0039-2480 ISSN 0039-2480 UDK 658.512.4:658.562 UDC 658.512.4:658.562 Kratki znanstveni prispevek (1.03) Short scientific paper (1.03) Zmanj{anje stro{kov v odpremi z uporabo metodologije {est sigm Reducing the Costs of Shipping Automotive Products by Imple-menting a Six Sigma Methodology Mirko Sokovi} - Miran Jure~i~ - Andrej Kramar Skupina za izboljšanje kakovosti in produktivnosti v podjetju TPV Johnson Controls, ki izdeluje avtomobilske sedeže za Renault Clio, je izpeljala projekt izboljšanja razmer pri odpremi sedežev. Povod za ta projekt je bila majhna zasedenost delavcev v odpremi, še zlasti voznika tovornjaka. S sistematičnim prijemom in timskim delom smo dosegli ugodne rezultate v obliki ukinitve enega delovnega mesta (enega delavca na izmeno) s prerazporeditvijo del in nalog na druga delovna mesta v odpremi in s tem dviga produktivnosti na zadovoljivo raven. Tako je uporaba metodologije šest sigm pri izvedbi tega projekta prispevala k precejšnjim prihrankom in izboljšanju uspešnosti poslovanja. © 2004 Strojniški vestnik. Vse pravice pridržane. (Ključne besede: metodologija šest sigm, zmanjševanje stroškov, učinkovitost dela) The team responsible for improving quality and productivity at TPV Johnson Controls, a company producing car seats for the Renault Clio, carried out a project to improve the efficiency of its shipping procedure. The reason for the project was the low labour efficiency in the shipping area, especially that of the truck driver. A systematic approach and teamwork abilities contributed to favourable results in the form of a lay-off of one workstation (one worker per shift) through a re-distribution of work assignments to other shipping 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 company and an improvement in its business performance. © 2004 Journal of Mechanical Engineering. All rights reserved. (Keywords: Six Sigma metodology, costs savings, labour efficiency) 0 UVOD Postopek, ki se imenuje Šest sigm, je relativno nov in se uporablja pri zagotavljanju kakovosti in vodenju kakovosti s poudarkom na stalnem izboljšanju kakovosti. Postopek izboljšav se uvaja skozi sistematično projektno usmerjeno metodologijo “definiraj, izmeri, analiziraj, izboljšaj in nadziraj“ DIAIN - DMAIC). Raven sigm pokaže možnosti za nekakovosten izdelek. V primeru ravni šest sigm so možnosti za neustrezen izdelek enake 3,4 kosov na milijon. Doseganje ravni kakovosti šest sigm vključuje vodstvo, infrastrukturo, ustrezna orodja in metode, pri čemer kakovost postaja del skupnega načrta poslovanja organizacije ([1] do [5]). 1 PROJEKT ŠEST SIGM 1.1 Faza - Definiraj - Opredelitev problema 0 INTRODUCTION Six Sigma is a new, emerging approach to quality assurance and quality management with the emphasis on continuous quality improvement. Process improvements are implemented in a systematic manner through DMAIC methodology: Define, Measure, Analyse, Improve, and Control. The Sigma level indicates the possibility of a defective product. In the case of a Six Sigma level, the chance of a defective product is equal to 3.4 ppm. Achieving a Six Sigma quality level involves leadership, infrastructure, appropriate tools and methods, and in addition, quality has to become a part of corporate business plan ([1] to [5]). 1 SIX SIGMA PROJECT 1.1 Define Phase - Problem Statement & Quantification gfin^OtJJIMISCSD 04-4 stran 219 |^BSSITIMIGC Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs Sl. 1. Opredelitev problema v oddelku odpreme [6] Fig. 1. Problem statement in the shipping area [6] - - V oddelku odpreme je 10 delavcev (pet v vsaki izmeni): voznik viličarja - lanser sestavnih delov, odpremnik SS (sprednjih sedežev), odpremnik ZS (zadnjih sedežev), voznik viličarja - odpremnik sedežnih garnitur in voznik tovornjaka. Odpremnika sedežev nalagata sedeže na palete za odpremo (najprej sprednje in nato še zadnje sedeže). Voznik viličarja - odpremnik odvaža palete s sedežnimi garniturami v začasno skladišče in jih potem po potrebi natovarja na tovornjak. Voznik tovornjaka dostavlja sedežne garniture odjemalcu (sl. 1). Zasedenost delavcev na odpremi je nezadovoljiva (manjša od 61 %). Cilj projekta Analizirati zasedenost delavcev v oddelku odpreme ter ukinitev enega voznika viličarja na izmeno. Upoštevani prihranki projekta Ukinitev voznika viličarja - odpremnika na izmeno/ na leto: $ 18 000 Skupni letni prihranek (dve izmeni): $ 36 000 - - There are 10 workers in the shipping area (five per shift): forklift driver-feeder, shipping operator FS (front seats), shipping operator RS (rear seats), forklift driver and truck driver. The shipping operators load the seats onto the pallets for shipping (first FS, then RS), the forklift driver moves the pallets with seat sets in the area between the shipping line and the temporary warehouse, and then loads them onto the truck. The truck driver delivers the seat sets to the customer, Figure 1. The labour efficiency is unsatisfactory (less than 61 %). Project Objective Analyse the labour efficiency in the shipping area and consequently lay-off one forklift driver per shift. Project Saving Forecast One forklift driver lay-off per shift/per year: $ 18 000 Saving per year (two shifts): $ 36 000 DM 12 - Spr. sedeži DM 55 - Zad. sedeži WS 12 - Front seats WS 55 - Rear seats ar seats ^v Zasedenost odpremnikov sprednjih in zadnjih sedežev in viličaristov-odpremnikov Efficiency of forklift drivers-feeders, shipping operators for FS and RS, forklift drivers Zasedenost voznika kamiona Efficiency of the truck driver Pričetek postopka Izdelani sprednji in zadnji sedeži Process start Front and rear sits Postopek Nalaganje na paleto in paleto sedežev na kamion ter lansiranje materiala na DM Izdelani sprednji in zadnji sedeži Process Feeding the line with components loading FS and RS onto the pallets and loading the truck Sl. 2. Začetek in konec (meji) postopka [6] Fig. 2. Process Start & End Points [6] VH^tTPsDDIK stran 220 Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs PROIZVODNI PROSTORI spoc Sl. 3. Slika poteka postopka ([6] in [7]) Fig. 3. Process Map ([6] and [7]) - Težišče projekta in Meje poteka postopka Kaj naj bi merili: Zasedenost delavcev v oddelku odpreme. Začetek in konec (meji) postopka sta podani na sliki 2. - Slika poteka postopka Slika 3 prikazuje “Sliko poteka postopka” za dejavnosti v oddelku odpreme. 1.2 Faza - Izmeri - Diagram ponovljivosti meritev Merjeno je bilo: nalaganje palet z garniturami sedežev ene na drugo, prevoz z odpremne proge v vmesno skladišče in prevoz prazne palete iz vmesnega skladišča na odpremno progo. Analiza ponovljivosti (sl. 4) kaže, da je izbran način merjenja ustrezen. Variiranje med večkratnimi ponovitvami meritev za posamezne dejavnosti je majhno. - Test normalnosti Test normalnosti podaja ugotovitev, ali lahko sklop podatkov obravnavamo kot normalno porazdeljene podatke. Vrednost P je namreč verjetnost, da dobimo natančen vzorec, če so podatki normalno porazdeljeni. Sledili smo pravilu: a) Vrednost P < a: podatki niso normalno porazdeljeni. b) Vrednost P > a: podatki so normalno porazdeljeni. - Project Focus & Process Boundary Map What was measured: Labour efficiency in the shipping area. The process start and end points are shown in Figure 2. - Process Map Figure 3 shows the “Process Map” for the activities in the shipping area. 1.2 Measure Phase - “Total Gage R&R” - graph The measured operations were as follows: stacking of full pallets, delivery from the shipping line into the temporary warehouse, and delivery of empty pallets from the temporary warehouse onto the shipping line. The Gage R&R analyses (Fig. 4) show that three operators were measuring consistently. The variation between multiple measurements for each individual part is small. - Normality Test The normality test shows whether a collection of data can be treated as normally distributed data. The P-value is the probability of getting an accurate pattern if the data are normally distributed. We follow the principle: a) P-Value < a: The data are not normally distributed. b) P-Value > a: The data are normally distributed | IgfinHŽslbJlIMlIgiCšD I stran 221 glTMDDC Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs R C h a r t b y O p e ra to r ^A v^ B y O p e r a to r i i t a--------------$---- ----J r Izbran način merjenja je ustrezen, > kar dokazuje izračun ponovljivosti meritev (rezultat znotraj mej 0 in 10 %) The selected measurement system is suitable, which is proved by the calculation of Total Gage R&R (the result is within the limits 0 and 10%)_________•* St. dev / StdDev Vir / Source Celotna ponov. meritve Total Gage R&R Ponovljivost Repeatability Reproduktivnost Reproducibility Delavec Operator Kos proto kosu Part-To-Part Celotna variacija Total Variation Študij var. / Study Var %Študij var. / %Study Var (SD) (5.15*SD) 0,09272 0,4775 0,09143 0,4709 0,01541 0,0794 0,01541 0,0794 2,30162 11,8533 2,30349 11,8630 Sl. 4. Analiza ponovljivosti Fig. 4. The Gage R&R analyses (%SV) 4,03 3,97 0,67 0,67 99,92 100,00 - “Diagram normalnosti verjetnosti in x , R-karta”. Oba testa za vseh 10 delavcev v oddelku odpreme kažeta, da sklop podatkov lahko obravnavamo kot normalno porazdeljenega in da so merjeni procesi stabilni, vendar neučinkoviti. Primer “testa normalnosti” za voznika viličarja - odpremnika v izmeni A je prikazan na sliki 5. - Diagram zasedenosti delavcev v oddelku odpreme Diagram zasedenosti na sliki 6 kaže, da sta voznika viličarja - odpremnika učinkovita le 55 %, voznik .999 .99 .95 .80 .50 .20 .05 .01 .001 Diagram normalnosti verjetnosti / Normal probability plot - “Normality Probability Plots”&“I and MR Chart”, for all 10 workers in the shipping area show that a collection of data can be treated as normally distributed data and that the measured processes are stable, but of low efficiency. An example of the “Normality Test” for the forklift driver in the A shift is shown in Figure 5. - “Box plots graph” - Labour efficiency in the shipping area The Box plots graph (Fig. 6) shows that the two forklift drivers are only 55 % efficient and the truck x in R-karta / I and MR chart 55.1 55.6 P-Value a > (0,05) The data are normally distributed Sl. 5. “Test normalnosti” za voznika viličarja - odpremnika v izmeni A Fig. 5. “Normality Test” for the forklift driver in the A shifts VH^tTPsDDIK stran 222 Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs 85 75 65 55 45 35 25 Delavci / Operators Sl. 6. Diagram zasedenosti delavcev Fig. 6. Box plots graph of the efficiency of operators tovornjaka pa samo 27 %. Torej, je bil cilj tima poiskati poti za bistveno povečanje učinkovitosti dela ter uporabo notranjih rezerv v oddelku odpreme in nazadnje ukiniti delovno mesto dveh voznikov viličarja (v vsaki izmeni enega). 1.3 Faza - Analiziraj - “Testiranje domneve” učinkovitosti za posamezna delovna mesta v izmenah A in B V podporo doseganju ciljev smo izvedli “testiranje domneve” učinkovitosti dela za vsa delovna mesta v odpremi, v izmenah A in B. Testi kažejo, da ni bilo razlike pri učinkovitosti enakih delovnih mest v obeh izmenah. - “testiranje domneve” učinkovitosti za A in B voznika viličarja - odpremnika driver’s efficiency is only 27 %. Thus, the target of the team is to find ways to substantially increase the efficiency and make use of internal reserves in the shipping area and consequently lay-off two forklift drivers. 1.3 Analyze Phase - “Hypothesis tests”of the efficiency in A and B shifts on all workstations To support the setting of targets we made “Hypothesis tests” of the labour efficiency in the A and B shifts on all workstations in the shipping area. The tests showed that there was no difference in the efficiency of the same workstations in the two shifts. - “hypothesis test” of the efficiency for A and B forklift drivers (FLDs) P-Vrednost a > 0,05 Sprejmemo "ničelno domnevo" Ničelna domneva Null Hypothesis Nasprotna domneva Alternative Hypothesis - Ho: u A izmena = u B izmena - Ho: n A shift = n B shift - H1: u A izmena # u B izmena - H1: fi A shift # fi B shift Dvo-vzorčni T-test in CI: A-% voznik viličarja in B-% voznik viličarja Two-Sample T-Test and CI: A-% FLD in B-% FLD Sr. vr. dt.drv. SE sr.vr. N Mean StDev SE Mean 21 55,314 0,460 0,10 21 55,419 0,446 0,097 ni razlike med zasedenostjo voznika viličarja A in B. P-Value a > 0.05 “Null Hypothesis ” accepted no difference between the efficiency of A and B forklift drivers. A - % voznik viličarja A - % forklift driver B - % voznik viličarja B - % forklift driver Razlika / Difference = mu A-% voznik vil. / FLD - mu B-% voznik vil. / FLD Ocena 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 Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs Ničelna domneva Null Hypothesis Nasprotna domneva Alternative Hypothesis - Ho: u A voznik viličarja = u B voznik viličarja = u voznik tovornjaka - Ho: fi A forklift driver = fi B forklift driver = fi truck driver - H1: u A voznik viličarja # u B voznik viličarja # u voznik tovornjaka - H1: fi A forklift driver # fi B forklift driver # fi truck driver »Analiza variance« za vse podatke (za potrditev razlike) / »Analysis of Variance« for all data (to confirm the difference) Vir / Source Subs Napaka / Error Celotno / Total A - % Voznik viličarja A - % Forklift driver B - % Voznik viličarja B - % Forklift driver Voznik tovornjaka Truck driver DF 2 60 62 SS 11428,69 11,33 11440,01 Sr.vr. / Mean MS F P 5714,34 3,0 0,000 0,19 StDev 21 55,314 0,460 21 55,419 0,446 21 26,795 0,396 P < 0.05; Zavrnemo "ničelno domnevo" P < 0.05; Null hypothesis rejected - “Testiranje domneve - ANOVA”: Učinkovitost voznikov viličarja - odpremnikov A in B ter voznika tovornjaka Iz opravljenega izračuna je razvidno, da ni nobene razlike v zasedenosti med voznikoma viličarja - odpremnikoma izmene A in B, kar pa ne velja za razmerje med voznikom tovornjaka in voznikom viličarja - odpremnikom izmene A in tudi ne za razmerje med voznikom tovornjaka in viličaristom-odpremnikom izmene B (obe vrednosti sta pozitivni razliki). Vse opravljene raziskave (Testiranje domneve, Testiranje domneve - ANOVA, Diagram zasedenosti, Analize izvora in vpliva napak (AIVP)) so dokazale, da so na odpremi delovna mesta, ki lahko prevzamejo določena dela in naloge od voznika viličarja - odpremnika (v obeh izmenah). 1.4 Faza - Izboljšaj - Akcija za doseganje cilja Skupina je razporedila dela in naloge voznika viličarja - odpremnika izmen A in B na druga delovna mesta glede na rezultate analize njihove zasedenosti (sl. 7). - “Testiranje domneve” za voznika viličarja / voznika tovornjaka (novo stanje) Glede na rezultate simulacije se je skupina odločila, da voznik tovornjaka prevzame dodatna dela (zamenjavo palet, nalaganje tovornjaka in zamenjavo akumulatorja na viličarju). Za statistično - “Hypothesis test - ANOVA”: Efficiency of A and B forklift drivers and the truck driver The calculation shows that there is no dif-ference between the efficiencies of the A and B forklift drivers, but this does not hold true for the ratio between the truck driver’s efficiency and that of the A forklift driver, in the same way as it is not true for the ratio between the truck driver and the B forklift driver (both values are positive – difference). All our researches (Hypothesis test, Hypothesis test - ANOVA, Box Plots graphs, Failure mode and effect analysis (FMEA)) so far prove that there are workstations in the shipping area that could take over some tasks from the forklift drivers (both shifts). 1.4 Improve Phase - Action to achieve the target With the help of the team we succeeded in distrib-uting the work assignments of the A and B forklift drivers to other workstations on the basis of their efficiency analysis (Fig. 7). - “Hypothesis test” for forklift driver - FLD / truck driver - TD (new situation) Based on the simulations the team decided that the truck driver should take on additional tasks (changing of pallets, loading the truck and changing the battery on the forklift). To Ničelna domneva - Ho: ,1 voznik viličarja = ,1 voznik tovornjaka Null Hypothesis - Ho: fi forklift driver = fi truck driver Nasprotna domneva - H1 ,1 voznik viličarja # ,1 B voznik tovornjaka Alternative Hypothesis - H1 fi forklift driver # fi B truck driver Dvo-vzorčni T-test za voznika viličarja proti vozniku tovornjaka / Two-sample T for FLD CH M sr.vr. / Mean StDev SE sr.vr. / Mean 30 6,7870 0,0223 0,0041 30 6,8003 0,0243 0,0044 P < 0,05; Sprejmemo "Ničelno hipotezo" P < 0.05; Fail to reject the Null Hypothesis voznik viličarja FLD CH. PALLET voznik tovornjaka TD CH. PALLET Razlika / Difference = mu voznik viličarja / FLD CH PALLET - mu voznik tovornjaka / TD CH. PALLET Ocena za razliko / Estimate for difference: -0,01333 95% 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 VH^tTPsDDIK stran 224 Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs Čaka na viličarju Menjava palete za odpremo Natovarja tovornjak Raztovarja tovornjak VILIČARIST-ODPREMNIK Sr. vr. jA shift = 55,31% B shift = 55,42% VOZNIK TOVORNJAKA Vozi tovornjak s polnimi paletami kupcu Dodana prevzeta dela Sr. vr. = 26,80% Menjava akumulator na viličarju Lansira sestavna dele na delovna mesta Lansira ostali material na delovna mesta Menjava palete za odpremo Natovarja tovornjak Raztovarja tovornjak Menjava akumulator na viličarju Odvaža prazne embalaže Odvaža smeti na deponijo Odpira embalažo Lansira vzglavnike zadnjih naslonov na DM | ODPREMNIK SPREDNJIH SEDEŽEV iPrenaša sedeže z linije sest na odpremno linijo | ODPREMNIK ZADNJIH SEDEŽEV Prenaša sedeže z linije sest na odpremno linijo iKnjiži SELEX etikete v informacijski sistem Sr. vr. = 78,86% Dodana prevzeta dela _ Knjiži SELEX etikete v informacijski sistem Sr. vr. = 74,90 % Dodana prevzeta dela ^^ Menjava palet za odpremo r Lansira vzglavnike zadnjih naslonov na DM Lansira sestavna dele na delovna mesta Odpira embalažo Nalaga in lansira vodila sedežev VILIČARIST-LANSER Sr. vr. "A izmena = 82,7 % B izmena = 82,8 % Dodana prevzeta dela Lansira podsklope "APA" Lansira blazine sedežev Odvaža prazne embalaže Lansira sestavna dele na delovna mesta Lansira ostali material na delovna mesta Odvaža prazne embalaže Odvaža smeti na deponijo Odpira embalažo Odvaža smeti na deponijo Čaka na viličarju Menjava akumulator na viličarju Sl. 7. Porazdelitev delovnih nalog voznikov viličarjev - odpremnikov A in B FORKLIFT DRIVER Mean TRUCK DRIVER Mean = 26,8011, Wait; on the forklift Ashift = 55,3111. | Delivers full/empty pallets to/from ihe customer | Change; the pallets for shipping Bshi ft = 55,4211: Additional re-assinned tasks Loads the truck ---------M Changes the pallets for shipping Unloads the truck n Loads the truck Changes the battery on the forklift --------n Unloads the truck Feeds the workstations with components --------^ Changes the batten/ on the foiklift Feeds the workstations with other material Removes e m ply boxes L _ Moves waste material to the waste-collection site Opens boxes Feeds the workstations with rear headrests SHIPPING OPERATOR FRONT SEATS Mean = 78 .sen. Additional re-assinned tasks I Loads the seats onto the pallets for shipping | w lEnters SELEX labesl into the IT s^tem | ] j/^ X | SHIPPING OPERATOR REAR SEATS Mean = J*$0 % Additional re-assiiined tasks Loads the seats onto the pallets for shipping jS Changes the pallets "for shipping | Enters SELEX labesl into the IT system r Feeds the workstations with rear headrests V FORKLIFT DRIVER-FEEDER Mean Additional re-assinned tasks Feeds the workstations with components Ashift = 82,7 ¦»¦ Feeds the workstations with components T Opens boxes B shift = 82,8 11, Feeds the workstations with other material Feeds the workstations with seat slides Removes empty boxes > ^ Feeds the workstations with "APA" Moves waste material to the waste-collection site Feeds the workstations with foams Opens boxes ^ Removes empty boxes Moves waste material to the waste-collection site Waits on the foiklift Changes the battery on the forklift Fig. 7. Distribution of the work assignments of the A and B forklift drivers stran 225 Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs Blok diagram za voznika viličarja in voznika tovornjaka (novo stanje) Boxplots of Forklift driver and Truck driver new (means are indicated by solid circles) 6.85- _L ¦= c ¦n cl to ° ,0 ^ 6.80- 6.75- x/ R-karta: primerjava za voznika viličarja in voznika tovornjaka (novo stanje) Xbar/R Chart comparison between Forklift driver and Truck driver new 6,85 — voznik viličarja forklift driver voznik tovornjaka (n truck driver new ovo stanje) 6,80 — V vv 6,75 — voznik viličarja forklift driver voznik tovornjaka (novo stanje) truck driver new 0 voznik viličarja forklift driver 10 20 voznik tovornjaka (novo stanje) truck driver new 30 A\. 0,05 — \ A 0,00 — ^V-"- Y X »—^ \ R=0,02867 LCL=0 Sl. 8. Blok diagram in x/ R-karta Fig. 8. Box Plots and Xbar/R Char potrditev upravičenosti naše odločitve smo naredili nove meritve in izračune. Blok diagram in x / R-karta (sl. 8) kažeta, da voznik tovornjaka lahko prevzame nalogo zamenjave palet od voznika viličarja - odpremnika. - Diagram zasedenosti delavcev v oddelku odpreme - novo stanje Diagram na sliki 9 prikazuje povečanje zasedenosti delavcev v oddelku odpreme, ki je posledica prerazporeditve delovnih nalog zaradi ukinitve delovnega mesta enega voznika viličarja na izmeno. 1.5 Faza - Nadziraj - “x/ R-karta” za delavce v odpremi V tej fazi smo preverili stabilnost novih postopkov in povečanje učinkovitosti, kar ponazarja uspeh projekta (sl. 10). statistically confirm the justification of our decision we made new measurements and calculations. The box plots and the Xbar/R Chart (Fig. 8) show that the truck driver is able to take over the task of changing the pallets from the forklift driver. - “Box Plots graph” for labour efficiency in the shipping area – new situation The graph (Fig. 9) shows the increase in labour efficiency in the shipping area, which results from the re-distribution of work assignments due to the lay-off of one forklift driver per shift. 1.5 Control Phase - “I and MR Charts” for shipping workers These charts prove the stability of the new processes and the rise in efficiency, which demonstrates the success of the project (Fig. 10). 90 80 70 60 50 40 30 20 Voznik viličarja - lanser, novo stanje Forklift driver - feeder, new Voznik viličarja - lanser A Forklift driver - feeder A Voznik viličarja - lanser B Forklift driver - feeder B Odpremnik ZS, novo stanje ' Shipping operator RS, new Odpremnik SS, novo stanje / Shipping operator FS, new stan Odpremnik SS / Shipping operator FS Odpremnik ZS Shipping operator RS Ukinitev Lay-off Voznik viličarja A 3 Voznik vili, arja B Forklift dri er B Forklift driver A E 3 Voznik tovornjaka, novo stanje Truck driver, new Voznik tovornjaka Truck driver Delavci / Operators T Sl. 9. Diagram zasedenosti za novo stanje v odpremi Fig. 9. Box plots graph for the new situation VH^tTPsDDIK stran 226 UCL=6,854 Mean=6,800 LCL=6,746 UCL=0,09366 Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs x in R-karta za voznika tovornjaka pred in po spremembi I and MR Chart for Truck driver before and after to 70 L J 60 2 TO >! 50 TO TO N-g 40 s= ¦- Q. 20 Subgroup voznik tovornjaka (pred) truck driver before voznik tovornjaka (potem) truck driver after ' Mean=61.64 ) 10 .voznik tovornjaka (pred) truck driver before 20 30 voznik tovornjaka (potem) truck driver after ------' UCL=3.884 R=1.189 LCL=0 Sl. 10. x/ R-karta voznika tovornjaka pred prerazporeditvijo nalog in po njej Fig. 10. I and MR Chart for shipping workers - Spremenjeni načrt nadzora V tej sklepni fazi metodologije DIAIN je bil razvit načrt nadzora, da bi zagotovili konsistentnost procesov in izpolnitev zahtev odjemalcev. 2 SKLEP Postopek Šest sigm zahteva sistematičnost in konstruktivno delo celotne skupine. Cilj šest sigm je izboljšati organizacijsko učinkovitost kakor tudi uspešnost pri zadovoljevanju odjemalčevih potreb ter resnično oblikovanje ekonomskega blagostanja tako za odjemalca kakor dobavitelja. V analiziranem primeru je podjetje doseglo prihranke v znesku 36.000 $ na leto. - Modified Control Plan In this final phase of the DMAIC methodology, a control plan was developed to ensure that the processes consistently meet our and the customer’s requirements. 2 CONCLUSION Six Sigma requires a systematic approach and the constructive work of the whole team. The objective of Six Sigma is to improve an organisation’s efficiency as well as its effectiveness in meeting the customer’s needs, ultimately creating economic wealth for the customer and the provider. In the analysed case the company achieved savings of $ 36,000 per year. 3 LITERATURA 3 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] Pavletič, D., M. Sokovič (2002) Six Sigma: A complex quality Initiative, J. of Mech. Eng., Vol. 48, No 3. [4] NN.: 6a Training MAIC, Johnson Controls, 2001. [5] N.N.: Interno šolanje za 6a, TPV Johnson Controls, 2001, 2002, and 2003 (in Slovene). [6] Jurečič M., M. Sokovič (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. Jurečič M. and M. Sokovič (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 October 2003, Piran, Slovenia, 267-274. | IgfinHŽslbJlIMlIgiCšD I stran 227 glTMDDC Sokovi} M., Jure~i~ M., Kramar A.: Zmanj{anje stro{kov - Reducing the Costs Naslova avtorjev: doc.dr. Mirko Sokovič Univerza v Ljubljani Fakulteta za strojništvo Aškerčeva 6 1000 Ljubljana mirko.sokovic@fs.uni-lj.si Miran Jurečič Andrej Kramar TPV Johnson Controls d.o.o. 8000 Novo mesto Authors’s Addresses: Doc.Dr. Mirko Sokovič University of Ljubljana Faculty of Mechanical Eng. Aškerčeva 6 SI-1000 Ljubljana, Slovenia mirko.sokovic@fs.uni-lj.si Andrej Kramar Miran Jurečič TPV Johnson Controls Ltd. SI-8000 Novo mesto, Slovenia Prejeto: Received: 8.1.2004 Sprejeto: Accepted: 8.4.2004 Odprto za diskusijo: 1 leto Open for discussion: 1 year VBgfFMK stran 228