Bratić, Diana (2015) Optimizacija procesa tiska na načelima Six Sigma = Optimization of the printing process on the principles of Six Sigma. Dissertation (PhD) thesis. Grafički fakultet. [Mentor: Milčić, Diana].
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Abstract
Six Sigma kao sveobuhvatna metodologija za unaprjeđenje kvalitete započela je svoj nagli razvoj 80-tih godina 20. stoljeća u Motoroli, a danas se uspješno primjenjuje u procesima poboljšavanja velikih poslovnih sustava. Primjena Six Sigma metodologije rezultira visokom razinom sukladnosti, povećanom sposobnošću procesa, smanjenim troškovima i povećanom profitabilnošću kao temeljnim odlikama konkurentnosti. Analizom teorije, kao i dosadašnjih istraživanja uočen je nedostatak modela za potpuno upravljanje kvalitetom koji bi rezultirao optimizacijom procesa tiska. S obzirom da se Six Sigma metodologija pokazala prikladnom za optimizaciju u različitim proizvodnim industrijama, cilj ovog rada bio je napraviti model za optimizaciju procesa tiska na načelima Six Sigme. Takav model omogućava kontinuirano ostvarivanje stabilnih i predvidivih rezultata, odnosno smanjuje mogućnost varijabilnosti procesa. Oblikovanje novog modela baziranog na načelima Six Sigme zasnivalo se na detekciji i grupiranju mogućih točaka u procesu tiska koje bi dovele do varijacija u proizvodnji, a time i na samom proizvodu. S obzirom da je Six Sigma statistička mjera funkcioniranja procesa, te joj je osnovna namjera mjerenje varijabilnosti procesa, praćenje promjena razine sigme poslužilo je kao indikator promjena u procesu. Stoga je bilo potrebno definirati moguće granice varijabilnosti u procesu, pa su se u tu svrhu odredili funkcionalni zahtjevi proizvoda. Za svaki funkcionalni zahtjev proizvoda definirale su se metode kontrole i kritične karakteristike proizvoda koje su se analizirale, te grupirale prema kategorijama uzroka. Također se definirao maksimalan opseg svake karakteristike određen donjom i gornjom granicom tolerancije, te točke kritične za kvalitetu. U prvom dijelu istraživanja analiziran je nulti proces da se utvrdi da li je proces u stanju statističke kontrole procesa, da li je normalno distribuiran i ispravno centriran u odnosu na definiranu i praćenu karakteristiku proizvoda. U analizi nultog procesa akcent je bio na izračunu trenutne razine sigme i preliminarne sposobnosti procesa. U drugom dijelu istraživanja definirani su funkcionalni zahtjevi proizvoda, kritične karakteristike proizvoda i točke kritične za kvalitetu, te je provedena skupna analiza 27 parcijalnih procesa. Na kraju je na osnovu dobivenih rezultata istraživanja napravljeno modeliranje i testiranje novog optimizacijskog modela. Okosnica izrade modela bilo je generiranje optimizacijske jednadžbe gdje je uzeto generiranje funkcije u ovisnosti o tri varijable. Odabrana metoda najmanjih kvadrata se uspostavila kao dobra aproksimacija krivulje s odstupanjem manjim od 1%.
| Item Type: | Dissertation (PhD) thesis |
|---|---|
| Mentor name: | Milčić, Diana |
| Thesis Committee: | Zjakić, Igor and Pap, Klaudio and Barišić, Mario and Žiljak Stanimirović, Ivana and Modrić, Damir and Milković, Marin |
| Defence date: | 17 March 2015 |
| Abstract in english: | As a comprehensive methodology for quality improvement Six Sigma began its rapid development in the 1980s in Motorola, and today is successfully applied for improvements in the processes of large enterprise systems. The application of the Six Sigma methodology resulted in a high level of compliance an increased process capability, the reduction of costs and increased profitability as a fundamental feature of competitiveness. Considering the fact that the analysis of a theory and previous research observed the lacks of models for total quality control that would result in optimizing the printing process, and that the Six Sigma methodology has proved suitable for optimization in various production industries, the aim of this study was to create a new model for optimization of the printing process based on the principles of Six Sigma. This model allows continuous achievement of stable and predictable results, and reduces process variability. Design of a new model based upon the principles of Six Sigma rests upon the detection and grouping of possible points in the printing process (Critical To Quality), leading to variations in production, and thus the product itself. With regard to the fact that Six Sigma is a statistical measure of process functioning i.e. it is an indicator of variations in the process, and it is the basic intention of measuring the variability of the process, the monitoring the changes in the value of sigma has served as an indicator of changes in the process. It was therefore necessary to define the limits of possible variation in the process, so functional requirements of the products were determined for this purpose, defining the methods of control and the critical characteristics of the products which was analyzed and grouped according to cause categories. Defined is also a maximum range of each characteristic determined by the lower and upper limit of tolerance, and critical to quality points. The first part of the research focuses on the analysis of the zero process to determine whether the process is in a state of statistical process control, and whether it is normally distributed and properly aligned with respect to a defined and observed characteristics of the product. In the analysis of the zero process the accent was set upon the calculation of the current level of sigma and preliminary process capability. In the second part of the research functional requirements of the products were defined, critical products characteristics and critical to quality points described, and 27 – pooled process analysis conducted. Finally, a new optimization model was designed based on the results of the research, as well as tested. The backbone of model design was to generate an equation where the generation function is taken as a function of three variables. The chosen method of least squares is established as a good approximation of the curve with deviation less than 1%. |
| Uncontrolled Keywords: | proces tiska, optimizacija, Six Sigma, SPC, varijabilnosti u procesu |
| Keywords in english: | printing process, optimization, Six Sigma principles, SPC, process variability |
| Subjects: | TECHNICAL SCIENCES > Graphic Technology |
| Institution: | Grafički fakultet |
| City: | Zagreb |
| Number of Pages: | 143 |
| Callnumber: | 655.3:658.562 BRA d |
| Inventory number: | 10029 |
| Depositing User: | Antonia Grgurović |
| Status: | Unpublished |
| Date Deposited: | 01 Jul 2015 09:30 |
| Last Modified: | 01 Jul 2015 09:32 |
| URI: | http://eprints.grf.unizg.hr/id/eprint/2249 |
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