A more conventional definition of lead time in the supply chain management realm is the time from the moment the customer places an order (the moment the supplier learns of the requirement) to the moment it is ready for delivery. In the absence of finished goods or intermediate (work in progress) inventory, it is the time it takes to actually manufacture the order without any inventory other than raw materials. The Chartered Institute of Procurement & Supply identifies "total lead time '' as a combination of "internal lead time '' (the time required for the buying organisation 's internal processes to progress from identification of a need to the issue of a purchase order) and "external lead time '' (the time required for the supplying organisation 's processes, including any development required, manufacture, despatch and delivery).
what is lead time in supply chain management
the time from the moment the customer places an order (the moment the supplier learns of the requirement) to the moment it is ready for delivery