Purpose – This paper seeks to analyse the internal materials flow in lean manufacturing in an assembly line of the Bosch factory, located in Spain. The objective is to develop a handling system in a small space, capable of solving the problems of accumulated intermediate stocks of parts. An improvement is proposed adopting the milkrun handling system, while verifying the advances by means of lean metrics. Design/methodology/approach – Based on this case study, the paper identifies data from value stream mapping and uses lean metrics, such as dock-to-dock time and lean rate. The case study develops a timetable and routing analysis for the milkrun to improve materials flow. Findings – The proposed logistics allows an improvement of lean metrics, without modifying the layout and production planning. The routing flexibility of the milkrun reduced stocks, work-in-process and dock-to-dock time, while increasing lean rate. Research limitations/implications – The findings are limited due to the focused nature of the case study. Although the solution is designed for a particular plant, the methodology is fully exportable. Practical implications – The paper shows a real case study illustrative for systems management. This research shows significant benefit associated with the implementation of lean programs. Originality/value – It details how the application of lean manufacturing tools could necessitate a study of materials handling to improve lean metrics.

Agile manufacturing systems work in a constantly changing global market, particularly assembly systems at the last stage of product differentiation. Meanwhile, sustainability is becoming a key issue for manufacturing strategy. This paper formulates a systemic criterion of sustainability in agile manufacturing and computes it through flexibility and complexity. It is defined as a ratio of utility and entropy as a sustainability measurement. Under a unified framework, utility allows one to quantify the contributions to agility, in particular system flexibility. Complexity is measured by entropy. Thus, an original complementary role of flexibility and the complexity of the system are proposed. Developed from the distribution of system states, the systemic approach to sustainability in terms of output evolution is enriched. Based on a simple assembly line integer model simulation, a first quantitative analysis illustrates the concepts introduced.

Collaborative robots are enablers of flexibility in the current dynamic and uncertain manufacturing environment. Decision making on its implementation requires technical feasibility, involving productivity and workforce implications that should be faced in an integrated perspective in processes where many components of different materials are assembled in products of increasing diversity and complexity. This study introduces two new parametric models for collaborative robotics, formulated in order to evaluate the differential cost of assembly (economic dimension) and the differential income from taxes that supports short-term workforce displacement (social dimension) in cobot implementation. Updated techno-economical parameters are selected for assessing feasibility ranges of application in different production scenarios. Next, the influence curves of productivity gain for a feasible implementation of cobot establish thresholds for decision making under both criteria. The results show the need for productivity gains that are significantly lower in high-wage scenarios than in low-wage scenarios; however, in a joint approach, breakeven productivity gain is always higher for the social dimension threshold than for the economic requirement of cost-effective manufacturing, with a higher gap in low-wage cases. The detailed analysis of a real case study of cobot implementation for assembly demonstrates the practical application of models and potential for future research.