3.2. Lead time reduction
Detailed analysis of production flow shows that the operative time (machine time) represents between 5 and 20% of the total lead time; on the other hand, inter-operation time (waiting, transfers, stocking) represents the longest period: 80}95%.
The objective here, is to accelerate flow by reducing batch size. In order to achieve that, it is necessary to implement a JiT/TQ philosophy.
Just in time is a manufacturing philosophy based on the planned elimination of all waste and on the continuous improvement of productivity. It encompasses the successful execution of all manufacturing activities required to produce a final product, from design engineering to delivery and including all stages of conversion from raw material onward. The primary elements of JiT are to have only the required inventory when needed; to improve quality to zero defects; to reduce lead times by reducing setup times, queue lengths and lot sizes [13]. We can summarize this global approach by the following logic: if we admit that stocks are a source of waste and a filter that hides problems, it is necessary to investigate the causes behind the constitution of stocks in order to accelerate flows.