Reduction

Use

If the dates that the system determines by scheduling an order or collective order lie outside the basic dates it can lead to the lead time being reduced. It uses the reduction measures that you have predefined. Possible reduction measures include:

Reduction or the order float (floats before and after production)
Reduction of the queue time and the move time of operations
Splitting, that is dividing up an operation among several people or machines
Overlapping, that is partially parallel processing of operations in a sequence
Reducing the operation durations

The lead time of the order is reduced step by step until the lead time lies within the basic dates or until the maximum reduction step is reached.

Prerequisites

You make the settings for reduction in Customizing and in the order or in the task lists:

In Customizing for Scheduling parameters you define the following per plant, per order type and per production scheduler:

the maximum reduction level
the scope of the reduction of the order float in every reduction level

You can still define these scheduling parameters in order maintenance or task list maintenance.

You define the reduction strategies in Customizing for reduction strategies. They define the selection and scope of the reduction measures in every reduction step for specific operations. In the order or task list you specify a reduction strategy for every operation for which a reduction is permitted.
In the order or in the task list you define for every operation the data for the operation-specific reduction measures (conditions for overlapping and splitting, normal and minimum move time and queue time).

Scope of functions

It basically depends on the order category which reduction measures you can define.

Order category	Possible reduction measures
Production orders, planned orders	Order float, queue time, move time, splitting, overlapping
Networks	Operation duration
Process orders	Order float, operation duration
Sales and operations planning (SOP)	Order float
Maintenance orders	No reduction possible

Reduction using the critical path

For collective orders, networks or planned orders and production orders with parallel sequences you can use the reduction type in Customizing for scheduling parameters to specify that the reduction measures are only to be carried out on operations where a reduction of the lead time also leads to a reduction of the overall lead time of the collective order or of the order. Such operations form a "critical path". Operations where a reduction of the lead time does not reduce the total lead time are not reduced. With this reduction type reduction measures are only executed to the extent that is necessary for reducing the lead time. In this way you retain the float times or avoid unwanted splitting or overlapping of uncritical operations.