Assembly lines for customized control cabinets

The objective of this thesis is to design an assembly line specification for highly customized products in production of the case company. The new assembly line must be more efficient than the current assembly process. A sub-objective of the thesis is to create an assembly line method" library" for the case company. First, a literature review is made. The aim of the literature review is to find out different assembly line methods. The main references for the literature review are scientific articles. Then, an evaluation study is made for the different assembly line methods. The evaluation study has two phases. Modified House of Quality matrix and Analytical Hierarchy Process (AHP) methods are used in the first evaluation phase. The first evaluation phase evaluates different assembly line methods against criterions. The AHP method is used to get weight factors for the criterions, then the evaluation of the assembly line methods in made in the modified House of Quality matrix. The first evaluation phase is mainly based on the professional skills of the author and the instructor of the thesis, and its results are applicable to the production environment of the case company and the corresponding production environments. In the second evaluation phase, a simulation study is made for the four most suitable assembly line methods which scored best in the first evaluation phase. With the simulation study, performance metrics (e.g. throughput and throughput-time) can be got for the assembly line methods. Results of the simulation study are not 100 % accurate, because the simulation cannot take into consideration all the real-life elements. But still, the results are indicative. As a result of the literature review, nine different assembly line methods are introduced. Mainly these assembly line methods differ from each other in the line balancing. The results of the first evaluation study show that the flexibility and the reliability of the production system are considered to be the most important criterions for the case company's production. In the second evaluation phase, one of the assembly line methods is proven to be significantly better than the others. Based on the simulation study, this assembly line method is proven to outperform also the current assembly process. In this study it is shown that dynamically changing line balance and cross-trained workers are important elements of a flexible and reliable assembly line. The simulation study also shows that the line balance has a significant effect on the throughput of an assembly line. In the thesis, it is recommended that the case company starts to use the assembly line method which performed best in the simulation study. The same assembly line method has also the above-mentioned elements. Based on the results, conclusions and recommendations of the thesis, this study fulfilled its objectives