Material and resource requirement lead times are calculated using the Calculate Manufacturing Lead Time concurrent program. This program determines the lead time for items and assemblies using information from the bill of material and routing setup. This includes lot size, item lead time attributes (such as processing and cumulative lead times), and fixed and variable components. The lead time calculation rollup program also includes resource usage features that can affect processing lead time.
You can set the profile option WIP: Round Off Resource Usage to Minutes in Lead Time Calculations to change resource usage calculations. If set to Yes - when entry of resource usage values of a routing resource is less than a minute value, this profile enables the value to be rounded to the next minute to be compatible with Advanced Supply Chain Planning calculations. This setting can change the resource usage rate. Otherwise, if set to No, resource usage is not rounded.
For scheduling and lead time calculations, extended resource usages are rounded to the next minute. In the following example, each resource usage is 72 seconds. The scheduling logic and lead time calculation round to the next minute - therefore each resource usage is rounded to 120 seconds, and the total duration is 240 seconds.
| Operation | Resource | Usage | Scheduled Flag | Basis |
|---|---|---|---|---|
| 10 | Resource1 | 72 seconds | Yes | Item |
| 10 | Resource2 | 72 seconds | Yes | Item |
Note: Alternate resources are not considered in lead time calculation.
Resource usage is divided by the efficiency percentage to capture the resource lead time. Values of less than 100 percent elongate the lead time.
You define a utilization percentage in order to capture true available-for-work time. Utilization represents the difference between the theoretical and actual production from a resource, For example, is the resource actually working 8 hours of productive time in an 8 hour shift. If the difference is expected to be significant, you can model utilization on that resource. Values of less than 100 percent elongate lead time.
When using two or more resources at the same time, the resource taking the most extended time is used in lead time calculation. This is the resource with the longest lead time within the same schedule number, for an operation. Simultaneous resources shorten lead time.
For resources available 24 hours, the more resource units assigned to an operation in a routing - the less elapsed time for that operation to complete. This shortens the lead time.