Evaluating the impact of lean techniques on sustainability performance in manufacturing industry: Single case study using Sustainable Value Stream Mapping

This study examines the effects of Lean techniques on the sustainability performance of manufacturing processes, focusing on an Italian company producing steel and concrete processing machines. Using Sustainable Value Stream Mapping (Sus-VSM), it assesses economic, environmental, and social sustainability before and after a Lean project on the straightener production line. The research is based on a single case study conducted from March to September 2023. Sus-VSM was applied to map the production flow and select key sustainability indicators across the three dimensions. Data were collected through direct observation, internal documentation, and questionnaires. Results show that major benefits include shorter lead time, more efficient inventory management, reduced CO2 emissions from suppliers, full employee training, and a shift to 100% local sourcing. The study also identifies useful metrics for evaluating the influence of Lean practices on each sustainability dimension. Although previous research has discussed connections between Lean and sustainability, few studies have empirically examined all three dimensions within a single operational context. Addressing this gap, the study supports an integrated understanding of how Lean contributes to sustainable performance. It also provides a practical and replicable framework, showing how Sus-VSM can help manufacturing firms monitor and enhance sustainability.