Performance improvement of manual assembly lines in a context characterized by complexity

The researchers' difficulty at transferring the scientific knowledge to practitioners and the existence of a gap among the methods developed in literature and the real life problem are issues recognized by literature and seems that they have not been solved yet. The aim of the present work is to outline a methodology that is successfully applicable to the industrial context, i.e. that is able to both take in account of the difficulty of managing a high number of different components and materials and assure the correct line balancing to gain performance improvement of the assembly lines as well as the maintain of such better performance over time. Among the techniques presented by literature, the "kaizen assembly" is exploited to perform the line balancing and to be transferred to practitioners. As the methodology addresses a typical industrial issue, it is outlined through its application to the case of an Italian plant of a chocolatier and confectionery company, leader in the market of premium quality chocolate. In order to get such a difficult result, firstly, a methodology to reduce the complexity is proposed and applied to the case study, by identifying groups of components distinct based on commonalities in the job elements and cycle times, rather than on part-IDs. Secondly "kaizen assembly" are performed and lean manufacturing techniques are applied in order to enhance the assembly lines performance and reach a set target. This allowed the company to achieve the performance objective and to maintain changes steady over time, confirming the validity of the approach.13-15 September 201