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 Slotting Heuristic

Use

This heuristic is provided for scheduling large order quantities (orders with lot size 1) for multi-variant products in make-to-order production for the short-term horizon. Even after only short runtimes, it is capable of delivering relatively good results. This heuristic is particularly recommended for dealing with problems mainly concerned with hard restrictions.

The heuristic creates a sequence for the planned orders that lie in a period (day or shift). The orders are dispatched with no gaps. The heuristic respects all restrictions that are defined “hard”. Therefore, it is possible that not all existing orders can be dispatched.

You can use the heuristic directly after the LP procedure to create planned orders with lot size 1 in the short-term horizon using the period packages already assigned to the lines of the line network.

Integration

You can carry out this procedure by:

  • Integrating it in a procedure package for the model mix planning run in Customizing for Model Mix Planning.

  • Accessing it from interactive sequencing. See also: Optimization in Sequencing

The procedure is defined in the function module /SAPAPO/SEQO_QS01_CALL and uses the table /SAPAPO/SEQC_GAV.

Parameters

  • The procedure can take all restriction categories into account. When you call up the procedure, you can determine which restriction categories should be taken into account. The restrictions should be classified as “hard”. Therefore, you can define that only the quantity restrictions are to be considered, for example. See also: Including Restrictions in Planning

    In restriction maintenance, you should bear in mind the following guidelines so that you make the optimal use of system resources:

    • Quantity restriction

      Reasonable values for minimum: No entry or a value greater than 0

      Reasonable values for maximum: No entry or a value greater than or equal to 0

    • Block restriction

      Reasonable values for minimum: No entry or a value greater than 1

      Reasonable values for maximum: No entry or a value greater than 1

    • Spacing restriction

      Reasonable values for minimum: No entry or a value greater than 0

    • K-in-M restriction

      Reasonable values for maximum: No entry or a value greater than 1

    • Equal distribution restriction

      Can only be defined as a soft restriction

  • You can limit the maximum runtime of the procedure.

  • The procedure can take into account a date earlier or later than the customer’s preferred date. When you call up the procedure for make-to-order production and for make-to-stock production, you can define whether you want to tolerate an earlier or later date.

    Caution Caution

    If you defined a date earlier or later than the customer’s requested date as a hard restriction the system firms the orders for the customer’s requested date. Then, in the short-term planning horizon when splitting a planned order into several planned orders with lot size 1 the result is negative as all orders receive the same date. Therefore, you should choose the weighting soft (priority 1) when taking the customer’s requested date into account.

    End of the caution.

  • You can save the parameters in a processing profile in Customizing for model mix planning, or you can enter them every time you call up the procedure.