Exploring Heuristics

You use heuristics for production planning to plan products in interactive planning or in the production planning run. The heuristics are divided into different groups:

The product heuristics can be entered in the product master and affect planning of this product in the planning run.

The planning run sequence is defined using the heuristics for process control that are specified in the initial screen for the production planning run. For example, product planning with components according to low-level codes results in a production planning run which is the same as planning in SAP S/4HANA MRP. Using the service heuristics that can be specified in the production planning run, you can execute other individual functions.

You can execute several heuristics, which belong to both production planning and detailed scheduling, for the same products in one planning run. The heuristics are executed in the sequence in which you entered them on the initial screen of the production planning run.

On the view Advanced Planning of the material master in S/4HANA, you specify a heuristic for product planning if the product is not to be planned using the standard heuristic defined in Customizing. In the planning procedure in Customizing, enter the standard product heuristic that you want to use to plan the products for which no heuristic has been defined in the product master.

Product heuristics can be entered in the product master and they then influence planning of this product in the planning run. In particular, special lot-sizing procedures can be implemented using these heuristics. The "Planning standard lots" heuristic is of particular significance: It corresponds to normal planning of a product using the lot size defined in the product master.

Reorder point planning can be mapped in PP/DS using the relevant heuristic. However, for materials planned using reorder point planning, the question arises if they should be planned in SAP S/4HANA and not transferred at all to PP/DS. Optimizing lot-sizing procedures are also mapped in PP/DS using a relevant heuristic.

If planning is to be executed using the continuous input / output function in the PDS, this can be achieved using the relevant heuristic in the product master.

You select the Use lot-sizing settings from heuristic option on the Lot Size tab in the heuristic. This indicator is not set by default. However, special product-specific parameters (for example, the exact remaining lot size or the parameters for planning safety stock) are still read from the location product master, even if you select this indicator.

Production Planning (PP) heuristics contain all strategy parameters required for each heuristic on the Strategy tab.

The heuristics with the strategy settings specified are used as part of a production planning run. If no strategy profile is maintained, the global parameters of the strategy profile defined in PP/DS are used (Planning Run field). This strategy profile and its parameters are also used as part of interactive planning (Interactive Planning field).

The adjustment function allows you to adapt planned independent requirements in line with sales order quantities. This is a particularly useful procedure for strategy 20, if you want to prevent partial quantities from being produced for which no sales orders have been received up to a certain time and no more sales orders are expected.

To adapt the requirements, execute the SAP_PP_015 heuristic. You can then decide which requirements have to be modified and when. You can also use this heuristic to adjust or delete any existing procurement proposals.

Using the SAP_PP_014 heuristic "Ascertaining Pl. Ind. Requirements", you can evaluate any outstanding planned independent requirements. The results of the evaluation can then be used to ask customers to place orders.

You are able to specify the adjustment horizon and the ascertainment horizon either in the product master or in the heuristic.

Schedule sequence: You use this heuristic to schedule selected scheduled operations in a particular sequence in the production planning run and the DS planning board. You specify the scheduling sequence in the heuristic settings. When you start the heuristic for the selected operations, the system deallocates these operations and then schedules them again one after another in the set sequence.

Dissolve backlog: You can use this heuristic to reschedule the backlog in the production planning run and the DS planning board using a resource; that is, you can automatically reschedule the operations that lie in the past in the planning period to the current date or in the future. The current date and current time is the default for the earliest possible start date for the operations to be rescheduled. You can use the offset time in the heuristic settings to shift the earliest possible start date into the past or into the future.

Schedule sequence manually: You can use this heuristic in the DS planning board to create a scheduling sequence of your choice for a group of selected scheduled operations and then reschedule the operations in this sequence. You create the sequence of operations manually on a graphical list interface when calling up the heuristic.

Minimize lead time: You can use this heuristic to reduce the lead time for orders in the production planning run and the DS planning board that carry out operations using selected resources. The system fixes the selected resources and thereby all the operations that are scheduled at these resources. Starting from each fixed operation, the system schedules the other operations of the affected order in such a way that time intervals between the operations of that order are as small as possible.

Schedule deallocated operations: You can use this heuristic to reschedule selected deallocated operations in the production planning run and the DS planning board.

Stable forward scheduling: This is suitable for the explosion of backlogs or capacity overloads with an unchanged scheduling sequence and multiple product levels.

Other DS heuristics such as Advanced backward scheduling, which is based on the requested dates during scheduling, can also be used in detailed scheduling and, for example, be incorporated into the heuristic profile of the detailed scheduling planning board.

The Stable forward scheduling PP/DS heuristic is suitable for exploding backlogs, for adjusting capacity overloads or for adjusting the plan to a changed level of available resource capacity, for example, due to resource stoppages in the short term. If, for example, a weekly detailed scheduling is carried out for the medium term, for example using the PP/DS optimizer, stable forward scheduling can be used to adjust the plan on a daily basis for the short term.

The Stable forward scheduling heuristic adjusts a given production plan to the new conditions across multiple production levels and on multiple finite resources by rescheduling the orders. When doing so, it attempts to retain the original sequence of the operations on the resources. Furthermore, the resource assignment of the processes is not changed, that is, alternative resources are not used.

The heuristic can be used both interactively in the detailed scheduling planning board and in the background in the production planning run. In the production planning run, this heuristic is also suitable for large volumes of data.

Summary:

• Operations in backlog are moved to a future date

• Capacity overloads are resolved

• The order sequence is not changed

• Operations on resources can be moved into the future

• Resource utilization remains the same

• Relationships and pegging are taken into consideration

• Customer dates can be violated

The objective of a production planning run is generally to create a "feasible" demand program.

The actual planning is normally broken down into several steps, like in the sample process given:

• To ensure consistent planning, the stage numbering algorithm for determining the low-level codes must be executed regularly. This algorithm may, for example, be scheduled either at the start of a planning run or separately at regular intervals (weekly).

• Normal material requirements planning is carried out with the SAP_MRP_001 heuristic. This planning is executed infinitely.

• In order to link the created structure of requirements and requirement coverage elements with each other on multiple levels (and therefore to be able to optimize on multiple levels later on), a heuristic for creating fixed pegging is used.

• The capacity planning step can be carried out with the optimizer, which, in addition, can carry out simultaneous sequencing with regard to setup times or scheduling delays.

• Following optimization, the fixed pegging edges utility is removed again.

There can be further steps. When setting up a planning run such as this, it is recommended that a step-by-step approach be taken so that the results of the individual planning steps can be verified in the test phase.