Lead Times Usage in Oracle Manufacturing

Lead time represents the duration in days required to manufacture or buy an item used in manufacturing a product. Lead times of make items are calculated using the work definition. Supply chain planning uses lead times of items to plan for material requirements. The lead time calculation determines requirement dates for available-to-promise calculations in order promising.

Note: Available-to-promise calculations are currently supported for only discrete manufacturing.

The following table illustrates all the key concepts related to lead time calculation.

Attribute	Description
Lead Time Lot Size	Quantity of an item used to calculate manufacturing lead times. The default lead time lot size is 1 but you can modify it to represent the typical lot size in which the item is manufactured or purchased. Note: For process manufacturing items, the lead time lot size is considered from the expected output quantity of the standard batch size of the primary work definition
Fixed Lead Time	This represents the time to process all the manufacturing steps which are independent of the lot size of an item. You can either manually enter the fixed lead time value, or it can be calculated as part of the lead time scheduled process. It's expressed in days.
Variable Lead Time	This represents the time to process all the manufacturing steps which are dependent on the lot size. You can either manually enter the variable lead time value, or it can be calculated as part of the lead time scheduled process. It's expressed in days per unit. Note: For process manufacturing items, the variable lead time is converted to days per unit in the item's primary unit of measure.
Processing Lead Time	The time required to make or buy an item. For a make item, it represents the number of working days taken to manufacture the lot size of an item while considering the shift duration of the plant. It's calculated by summing the fixed lead time, and the variable lead time multiplied by the lot size. Processing lead time = Fixed lead time + (Variable lead time * lead time lot size) For a buy item, it represents the time required by the supplier to supply the item. It represents the lead time from the time the purchase order is released to the time when the item is received. You must manually assign a value. It's expressed in days.
Preprocessing Lead Time	Component of the lead time that represents the time required to release a purchase order or create a work order from the time you learn of the requirement. You can manually enter preprocessing lead time for both make and buy items. It's expressed in days.
Postprocessing Lead Time	For buy items, it's the component of the lead time that represents the time to have a buy item available in inventory from the time you receive it. For make items, it's the lead time of activities performed after manufacturing operations are completed, but before the item is available for shipping or the next stage of the manufacturing process. You must manually assign a value for each item. It's expressed in days.
Cumulative Manufacturing Lead Time	Total time required to make an item if you had all raw materials in stock, but had to make all subassemblies level by level. It's expressed in days.
Cumulative Total Lead Time	Total time required to make an item if no inventory existed, and you had to order all the raw materials and make all subassemblies level by level. It's expressed in days.

The manufacturing lead time calculation calculates the fixed and variable lead times in order to calculate the processing lead times. It's calculated based on the primary work definition of the item. The plant calendar shift exception and the work center resource exception aren't considered in the calculation.

The lead time percent value is calculated and updated for each operation in the primary work definition. The lead time percent represents the offset of a given operation as a percentage of the manufacturing lead time considering all operations of the work definition. These lead time percent values are used as an input in the calculation of cumulative lead times to compute the cumulative manufacturing lead time and cumulative total lead time.

In discrete manufacturing, manufacturing lead times can be computed optionally for assemble-to-order models. However, this will represent inflated lead time values for all possible configurations within that assemble-to-order model item. Manufacturing lead time calculation isn't supported for assemble-to-order configured items. The calculation of the cumulative lead times aren't supported for assemble-to-order model items and configured items

For computation of cumulative lead times, the hierarchy to roll up lead times are calculated using the primary work definitions at each level.

Note: Lead times aren't computed for items in a reference organization.