Control charts for variables

U ovom radu predstavljena je metodologija kontrole kvalitete kontrolnim kartama. Detaljno su opisani postupci analize podataka prije upotrebe kontrolne karte kao i smjernice za odabir kontrolne karte s obzirom na vrstu procesa koji se analizira. Prikazana je jasna klasifikacija kontrolnih karata te je dan generalan uvid u svaku od njih. Dane su precizne upute za konstrukciju svake od karata sa jasnim izrazima za proračun parametara kao što su kontrolne granice, očekivanja, standardna odstupanja, sposobnost procesa i sl. Korištenjem probne verzije softverskog paketa Minitab, dane su vizualizacije raznih tipova procesa predstavljenih u radu. Vizualizirani su i parametri prosječnog vremena odziva s obzirom na veličinu uzorka s čime je olakšano predočavanje alfa i beta rizika procesa. Nadalje, realiziran je značaj korištenja SPC softverskih paketa u industrijama današnjice, te je dan generalan pregled u komercijalno dostupne SPC softverske pakete sa komentarima i recenzijama istih. Primjeri u radu pokazuju široku primjenjivost kontrolnih karata na različite tipove procesa. Imajući načela kontrole kvalitete na umu, dana je analiza rezultata procesa. Za kraj, rezultati su komentirani te je potom naveden zaključak.In this final paper, the purpose and the quality control methodology using control charts is presented. The procedures such as data analysis that should be done before using the control chart are described in detail, as well as guidelines for selecting the control chart regarding the type of process being analyzed. A clear classification of control charts is presented and a general insight into each of them is given. Precise design instructions for each of the charts are given alongside the expressions for the calculations of parameters such as control limits, expectations, standard deviations, process capability, etc. Using the free trial of Minitab software package various visualizations are shown for different cases. The parameters of the average response time and average run length with respect to the sample size were also visualized, which facilitated the presentation of the alpha and beta risks of the process. Furthermore, the importance of using SPC software packages in today's industries was realized, and a general overview of commercially available SPC software packages with comments and reviews of the same is given. Examples in the paper show the wide applicability of control charts to different types of processes. With quality control principles in mind, an analysis of the process results is given. Finally, the results are commented and then a conclusion is given