Analysis of Lean Manufacturing Implementation Challenges in Small and Medium-Scale Metal Fabrication Enterprises in Nnewi

Lean manufacturing principles offer significant potential for improving productivity, reducing waste, and enhancing competitiveness in Nigeria's informal and semi-formal metal fabrication sector, yet documented evidence of structured lean implementation and its associated challenges in this context remains scarce. This study analyses the challenges encountered in lean manufacturing implementation in ten small and medium-scale metal fabrication enterprises in Nnewi, Anambra State. A qualitative case study approach was used, with data collected through in-depth interviews with enterprise owners and production supervisors, direct observation of production floor activities, and review of available production records. Lean waste identification was conducted using value stream mapping for a representative product family in each enterprise. Implementation barriers were categorised using thematic analysis into organisational, workforce, technical, and external environment categories. Findings revealed that resistance to procedural change among skilled artisans, lack of management commitment to sustained improvement activities, inadequate record keeping for baseline performance measurement, and erratic raw material supply disrupting flow were the most persistently reported challenges. Value stream maps revealed average process efficiency ratios of 34 percent, indicating substantial non-value-adding activity. The study proposes a contextually adapted lean implementation roadmap that accounts for the informal organisation structures, skill profiles, and supply chain realities of the Nnewi fabrication cluster. Keywords: lean manufacturing, waste reduction, metal fabrication, implementation challenges, Nnewi.