Non-Specific Causes of Lead Time Extension
- Suppliers are not supplied at the same frequency.
- Components are not of uniform complexity: hence individual components will have unique lead times.
- Sequential interdependence of assembly stages means knock-on effects of delays are felt downstream.
- MRP – a “closed loop” system – is not a truly “blind” lean thinking approach.
- The presence of multiple active suppliers prevents full automation. Short lead times of individual modules do not necessarily translate to system-wide time efficiency (Chopra, 2007) – the whole is greater (slower) than the sum of the parts (the sum of the lead times for each separate module).
- Data errors will occur.
- Human errors will occur.
- Customer cancellations of orders/modifications to orders prevent a very lean system.
- The manufacturing system is dependent on small lot sizes and high flow, which means low stockholding costs at Smartville but high reordering costs and strain on Tier 2 suppliers.
- Defective suppliers cannot be easily replaced, due to their embeddedness.
- Failings that cannot be resolved are locked into the system.
- The open loop system is not tolerant of order change, so speedy assembly might limit the possibility of ad hoc modification.