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Cumulative Lead Time Computations

Bills of Material computes cumulative manufacturing lead time and cumulative lead time by stepping through indented bill structures. Item information is updated as part of the both cumulative calculations.

Cumulative Manufacturing Lead Time

Bills of Material sets an item's cumulative manufacturing lead time equal to its own manufacturing lead time plus the maximum value of the cumulative manufacturing lead time for any component, adjusted for operation offset. The operation offset is the lead time percent for the operation where the component is used times the item's manufacturing lead time (based on one lead time lot size).

Purchasing items have no cumulative manufacturing lead time.

Bills of Material uses the following formula to compute cumulative manufacturing lead time:


Cumulative Total Lead Time

Bills of Material sets an item's cumulative total lead time to its own total lead time plus the maximum value of cumulative total lead time less operation offset for any component. Operation offset for a component is the lead time percent for the operation where the component is used times the item's manufacturing lead time (based on one lead time lot size).

Bills of Material calculates cumulative total lead time using the following equation:


For example, suppose Item A is made up of B, C, and D. B, C, and D are used at operations 20, 30, and 40 respectively and the manufacturing (processing) lead time for A (for the lead time lot size) equals 10. The following table illustrates the component, offset days, and lead time percent for each component:

Component Cum. Mfg. Lead Time. Op Seq. Lead Time Percent Offset Days Cum Mfg. Lead Time - Offset Days
B 15 20 20 2 13
C 20 30 40 4 16
D 22 40 80 8 14

Table 4 - 33. Cumulative Manufacturing Lead Time

Bills of Material calculates cumulative manufacturing lead time as follows:


And, the following table illustrates the cumulative total lead times assigned to components B, C, and D:

Component Cum. Total Lead Time. Op Seq. Lead Time Percent Offset Days Cum Total Lead Time - Offset Days
B 19 20 20 2 17
C 20 30 40 4 16
D 23 40 80 8 15

Table 4 - 34. Cumulative Total Lead Time

Bills of Material calculates cumulative total lead time for A as follows:


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