Utveckling av komponentupparbetningsflödet på Duroc Rail AB

Sammanfattning: The thesis comprised 800 hours and was conducted for Duroc Rail from January to June 2018. The company maintains railroad wheelsets through three types of measure; turning, revision and changing of wheels. The wheelsets can be divided into three groups based on the bearing type, they have different renovation procedures and are: cylindrical bearings, TBU bearings and spherical bearings.   The purpose of the project was to analyse and adapt the maintenance system to cyclically changing volumes, the changing mix of maintenance with respect to bearing type and increasing quality control requirements. The adaptation of system was delivered through solution proposals that facilitate the continuous recurring challenges and main problems of the maintenance system.   Lean was the focus area of ​​the theoretical framework as the core issues of the subject concerned the main problems encountered in the mapping of Duroc Rail. Planning and execution has been based on the Ranhangen (1995) description of the Project Circle. The basis for zero-state analysis was interviews, observations, data collection, time studies and internal documents. The simulation models changed step by step to analyse the effects of each change and validated against the real system to ensure validity of the models. Full technical data for workstations were missing and thus the capabilities could not be completely determined, which was expected for this type of work.   The simulation results gave clear indications of how small well-balanced changes to the system strongly affect the analysed parameters; average lead time and throughput. With simple means, bottlenecks and average lead times can be reduced and the throughput could still be increased. Proposed changes for the future simulation model were in line with the proposals from the theoretical framework and could therefore be integrated with good results. Improvement proposals were then considered after analysis of the theoretical framework and simulations results were implemented in the scheme proposed at the end of the improvement proposal chapter with staff involved throughout the changes.   The investigated main problems, lead time and material handling, make it difficult for the organisation to handle its specific challenges; fluctuating capacity requirements, changing mix and high-quality requirements. The company has good conditions for reducing lead time and reducing wheelsets in work, i.e. solving the main problems that the project focused on. By addressing the problems, the system's responsiveness can be greatly improved, which facilitates quality work, flow throughput and maintenance mix changes.   The risk with the suggested improvements is that the introduction of continuous flow and standardized working methods leads to labour intensification, which can be avoided through continuous improvements with a high level of involvement from the employees.