To calculate production times of operations

To offset lead-times, and to calculate start dates, end dates, and delivery dates, LN must know, among others, the production time of operations. This topic describes the method LN applies to calculate the production time of an operation.

The method LN uses to calculate the production time first of all depends on whether or not the operation has a fixed duration. You can use the Fixed Duration check box in the Production Planning (tisfc0110m000) session to make the appropriate setting.

Production time of an operation

If you do not select the Fixed Duration check box in the Production Planning (tisfc0110m000) session, LN applies the following formula to calculate the production time of an operation:

production time = average setup time + cycle time

The order quantity (batch size) in this calculation is the quantity planned input.

Operation with fixed duration

If you select the Fixed Duration check box in the Production Planning (tisfc0110m000) session, LN applies the following formula to calculate the production time of an operation:

production time = average setup time + cycle time

You can define the default value for fixed duration in the following sessions:

  • Task Relationships (tirou0104m000), which defaults the fixed duration value to:
    • Generic Routing (tipcf3120m000) (for operations in a generic routing).
    • Routing Operations (tirou1102m000)

LN uses the data of these sessions to get operation lead times for production planning.

Note

You cannot select the Fixed Duration check box for an operation if you selected the Transfer Batch Less Than Production Batch check box in the Production Planning (tisfc0110m000) session for the preceeding operation, which, in practice, is impossible. For example, if you bake bread rolls in an oven, all the bread rolls must stay in the oven for the full fixed duration time.