The effect of set management on just-in-time manufacturing

The authors describe the implementation of the set management concept at IBM in Hopewell Junction in 1990. Set management is designed to release a package of layers, which have been combined at the substock crib, into a substrate part number, significantly lowering material handling and inventory levels resulting in improved test yields. In the revolutionized set management approach, layer job release was triggered by a new software system which balanced sets. When completed each layer job was placed directly into the magazine from which it would be released into stocking, eliminating handling steps and kitting. Inventory reduction was immediately visible with inventory levels going from 30-40 days to less than 10 days. Implementation of set management led to a 7% improvement in yield, a 6× reduction in layer inventory, a 3× reduction in crib storage time, and multiple handling and inspection reductions. The savings to IBM amounted to over $12 million. Process change results are now seen on a real-time basis. Software was instituted to do daily inventory checks and ensure that the line is loaded with the correct mix of part numbers to meet the highest measure of serviceability possible