Fokusområden vid mixed-model assembly - En fallstudie på Unicarriers i Mölnlycke

Abstract

E2015:034, Unicarriers production facility in Mölnlycke is manufacturing several different models of trucks for indoor use. The assembly flows covered in this study consists of two assembly lines and a collective assembly station. Unicarriers are already using mixed-model assembly but could potentially increase resource utilization of the final assembly by merging the three assembly flows. The purpose of this Bachelor Thesis was to investigate which focus areas that are the most critical for mixed-model assembly and to analyse Unicarriers operations based on the identified areas. The study was made on the presumption that the production flows should be merged into a continuous flow mixed-model assembly line and aimed to determine which models that should be included on that line. A literature review was conducted to identify the key elements for effective mixed-model assembly. This resulted in six focus areas: standardized work, handling of complex line balancing, model sequencing, reduce length of materials façade and minimise picking and assembly errors. Sales volume, assembly time and common assembly tasks were identified as important aspects to evaluate the appropriate model mix. A first conclusion is that Unicarriers, based on the identified focus areas, have several areas to improve in order to increase resource utilization in the current manufacturing setup and in a future continuous flow mixed-model assembly line. The main methods and solutions to improve the current manufacturing setup are: standardized work for assembly and material supply, revised time studies and sequencing rules in the final assembly flows. A future continuous flow line is recommended to consist of open stations, weighted average cycle time, digitized information flows and poka-yoke solution. A second conclusion is that all the models manufactured at the considered production flows are not suited to form a model mix for efficient production on one mixed- model assembly line. The model mix should consist of smaller groups when sales volume, assembly time and common assembly tasks are considered. However, the exact model mix should be further investigated by considering more factors. The study deals with the mixed-model assembly in a general manner and can therefore be seen as a basis for further studies within each focus area.