PROBLEM SOLVING WITH THE USE OF SIX SIGMA METHODOLOGY AND TOOLS: a case study of the company Domel d.o.o.

V diplomskem delu je predstavljeno reševanje problema s pomočjo metodologije in orodij šest sigma. V teoretičnem delu je predstavljen DC motor s trajnimi magneti ter izdelava rotorja in sestava motorja. Opisana je metodologija šest sigma ter najpogostejši in najbolj znani model v metodologiji šest sigma - DMAIC model. V praktičnem delu je predstavljen problem nedoseganja življenjske dobe motorjev in po fazah DMAIC metodologije opisan pristop k reševanju tega problema. Prva faza v praktičnem delu diplomskega dela zajema definiranje začetnega stanja pred uvedbo končne rešitve in določa cilje, ki se želijo doseči s projektom DMAIC. V drugi fazi je predstavitev in opis izvedbe meritev, katere so potrebne za uspešno rešitev problema. V tretji fazi so predstavljene vse analize, katere so se izvajale pri iskanju možnih vzrokov za nedoseganje minimalne življenjske dobe in odpovedi motorjev. V zadnjih dve fazah projekta DMAIC je predstavljena uvedba novega stanja v proces in kontrola izboljšanega procesa. V zaključku diplomskega dela je izdelana primerjava procesa pred uvedbo novih rešitev in po uvedbi ter vse skupaj tudi grafično prikazano.The purpose of this diploma thesis is to address the problem by using the methodology and tools six sigma. In the theoretical part, the DC motor with permanent magnets is presented, as well as the production of the rotor and the assembling of the motor. The six sigma approach is described as well as its widely adopted DMAIC methodology. In practical part, the problematic of not reaching the life time of motors is presented and in addition, the approach to solving this particular problem. The first phase in the practical part of thesis includes definition of the initial state before the introduction of the final solution and determines goals which it seeks to achieve with the DMAIC project. In the second phase, description of the execution of measurements that are needed for a successful solution of the problem is presented. In the third phase results of the analysis which were implemented in searching possible causes for not reaching the minimal life time and cancellation of the motors, are presented. In the last two phases of the DMAIC project, the implementation of the new solution of the improved process is presented as well as the control of the improved process is described. In the completion of the thesis, the comparison of the process before and after the implementation of the new solutions is presented and graphically depicted