The degree dissertation deals with the transformation of alternator assembly from the classic line to U-cell, which was designed thanks to the production optimisation method in order to apply the principles of lean manufacturing. Among others, a cardboard mock-up line of the cell of 1:1 proportion was used to simulate the distribution of workplaces and operations to ensure the optimum performance of labour during the cycle. By transitioning from the production line to a U-cell, both the product as well as the volume registered an increase in flexibility. The U-cell shall enable a swift rearrangement of devices and tools as well as the assembly of various types of alternators. Since the U-cell offers the possibility to alter the workflow, it shall facilitate the adjustment to different demands as far as the product volume is concerned. The flux of material also improved, with an enhanced traceability of products during the assembly process and a substantial improvement in the availability of the production hall.