Assessing the Impact of Lean Tools on Sustainability—A Case Study

This article assesses the impact of the structured application of Lean tools on the sustainability of the operations of a Portuguese industrial company dedicated to the design, manufacture, and marketing of machinery for the industrial sector. The main goal was to understand how the integration of Lean practices can simultaneously strengthen an organization’s economic, social, and environmental performance. At the same time, it was intended to address the scarcity of studies that systematically examine the selection and adaptation of these tools in medium-sized companies, characterized by high product variability and complex logistics flows. To this end, the Action Research methodology was used, which combines theoretical review with practical application. The initial diagnosis, conducted through Value Stream Mapping, identified waste and opportunities for improvement. Based on this survey, an action plan was developed and executed using the A3 Problem Solving methodology, highlighting the implementation of a Kanban system between the warehouse and the Product 2 assembly line. The results demonstrated significant progress in the three dimensions of sustainability: a reduction in the average supply lead time from 16.05 h to 11.57 h per module (economic aspect); increased material availability, shifting constraints previously attributed to the warehouse to items from pre-assembly or not included in the system (social aspect); and an approximately 30% reduction in the energy consumption of the supply support device (environmental aspect). Therefore, it is concluded that the integration of Lean practices, framed within the Triple Bottom Line perspective, constitutes an effective approach to enhance the sustainable performance of organizations, in a balanced manner on three fronts: economic, social, and environmental.