Analysis of Production Bottlenecks in a Plastic Pipe Manufacturing Plant in Oyo State

This project analyses production bottlenecks in a plastic pipe manufacturing plant in Oyo State, South West Nigeria, applying industrial engineering tools to identify constraints limiting overall plant throughput. Plastic pipe production plays a critical role in Nigeria's construction and water supply infrastructure sectors, and manufacturers face increasing pressure to deliver higher volumes and shorter lead times in a competitive domestic market. This research employs the Theory of Constraints five-step focusing process to identify, exploit, and elevate bottleneck resources within the production system. Throughput time, queue length, and machine utilisation data were collected through direct observation and production record analysis over a ten-week period covering extrusion, haul-off, cutting, inspection, and packing operations. Results identify the extrusion stage as the system constraint, with an average utilisation rate of ninety-four percent compared to fifty-eight to seventy-two percent for downstream stages, resulting in persistent queue build-up at the extrusion line output. Investigation reveals that frequent die-head cleaning interventions, averaging forty-five minutes each occurring three times per shift, constitute the primary cause of extrusion throughput limitation. Recommendations include investigating alternative lubricant formulations to extend die-head cleaning intervals and scheduling cleaning during planned breaks to minimise productive time loss. Keywords: Theory of Constraints, bottleneck analysis, plastic pipe manufacturing, Oyo State, throughput