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Model Mix Planning: Planning Line Networks (New) ( RELNAPO_310_PPS_MMP )
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Short text
Model Mix Planning: Planning Line Networks (New)
Use
In the automotive industry, vehicles with many variants and assemblies with a high order volume are usually manufactured on the same takt-based production lines, which are linked in a line network. You can use Model Mix Planning to plan production for this form of manufacturing.
The aim of Model Mix Planning is to create a production plan in the mid-term to long-term planning horizon. When doing this, the system must take into account the delivery dates, the available capacities and, if necessary, any existing restrictions. The system generates period packages (these are planned orders for a product that are grouped together and for which the start and finish dates lie in the same period (day or shift)) that are already assigned to the lines used for processing them.
In the short-term planning horizon, the system uses the period packages to determine a sequence of orders with exact start and finish dates. The system takes into account delivery dates, available capacities, and restrictions.
Up to now, you could use model mix planning only to plan individual lines. For SAP APO 3.1, it is now possible to use it to plan a whole line network. The line network can consist of many lines that run sequentially or parallel to each other and that can be used as alternatives to each other. To generate a production plan for all products that are manufactured on the same line network, model mix planning is executed as a multiline planning. That means, the system takes into account all lines in a line network and all products that are used or produced on the various parts of the line network.
You can use interactive sequencing, as before, to process the planning results in the short-term horizon. You can change the sequence of orders on a line manually by using interactive sequencing or by accessing the corresponding procedure. In the new release, interactive sequencing has been enhanced with the following functions:
- Manual rescheduling of orders to an alternative line
- Display tracking information for an order
- Starting actions for a particular order
In the following paragraphs, details are given about the prerequisites for planning line networks with groups of alternative lines and about the planning run:
Prerequisites for Multiple Line Planning
To plan multiple lines, that is, to plan for a whole line network that can consist of alternative lines, you must use both the APO System and a DI System with Release DI 4.6C2. You use the DI System to maintain
the iPPE data that consists of the product structure, process structure and the line design.
In the following segment, details are given only with regard to the data in the line design.
You enter the following elements in the line design and maintain both the corresponding hierarchy relationships and the sequence of the individual elements:
- Line network with parts of the line network
- Alternative line groups for the lines that can be used as alternatives for each other
- Lines
- Line segments, if necessary
- You must set an element from the line network as a planning segment. You set the corresponding indicator either for a group of alternative lines or a line if this line does not belong to a group of alternative lines. You use the planning segment to determine the start of your planning. The system plans for this line and determines the start and end times for the orders by using the scheduling data for this line. You use forward scheduling or backward scheduling to calculate the start and end times on the lines that are before or after this line.
You create a line balance for the line network and enter a line balance rate, which is used to determine the takt time. Then you assign the activities of the process structure to the line segments so that the activities can be executed in the predefined takt time.
For the products to be planned, you create the iPPE access object in the production version and enter the line network and part of the line network there. If a product can follow several alternative paths through a line network, then you represent this by using various parts of the line network. For each part of the line network, you must maintain an iPPE access object and a production version.
You transfer the iPPE data to the APO. When you do this, the system automatically generates line resources in APO by using the data from the line nodes. You must then maintain the planning-relevant master data, such as the base rate and shift programs, manually in the APO System. This is necessary because the line resource forms the basis of the planning. The system uses this rate to determine the takt time that is used for scheduling in model mix planning.
In the APO System, you must take note of the following new or changed IMG activities for model mix planning for multiline planning:
- In the IMG activity Define LP Procedure, you check the settings for the linear program optimization procedure. This is a new optimization procedure for the planning of line networks with alternative line groups in the mid-term to long-term planning horizon.
- In the IMG activity Define Procedure Packages, you define a procedure package for the multiline planning and assign a reference calendar to it. For the long-term horizon, you choose between the Materials planning procedure and the LP procedure. For the medium-term horizon, you must enter the LP procedure in the procedure package. For the short-term horizon, you can choose between the genetic algorithm and the prioritized equal distribution.
Process for multiline planning
In the model mix planning run, the system examines the whole environment for the line/line network entered in the access screen. This environment is based on the relationships of the iPPE nodes and the production versions. In this way, the sytem determines all products that are affected and the possible paths through the line network.
In the next step, the system reads the Customizing settings and calculates the planning horizon. The system determines the available capacities of the line resources for each day of this horizon.
The system uses the LP procedure to assign the existing requirements for each day to the lines taking available capacities and any predefined restrictions into account. The system generates period packages for these requirements. The system uses the start and end time of the period (shift or day) in which the planned order is scheduled as the start and end date of the planned order.
Period packages that lie in the short-term horizon are split into planned orders with a lot size of
1 using the defined procedure, for example, the genetic algorithm. The system uses the procedure that
is defined in Customizing to determine the sequence of orders with the exact start and end dates for these planned orders.
Transferring the order sequences to production:
If you link a production control system to APO, you can execute a data transfer between the APO System (as the planning system) and the external system (which is responsible for production or assembly control).
After sequencing, you transfer the order sequences. This means that, at the request of the production control system, APO transfers sequence-optimized APO planned orders to the production control system in blocks for further processing.
The following new functions are available:
- Determining the parameters for transferring the planned orders
- You define how the transfer of the orders is to be carried out in the IMG activity Transferring Order Sequences to Production. You define, for example, that an ATP check is to be carried out for the orders before the transfer to determine whether all the necessary components are available. See also: ATP Check in the PP/DS.
- Synchronization with orders already received from the production control system
- When transferring the sequence-optimized APO planned orders from the APO system to the production control system, it is now possible to retransfer orders to the production lines which have already been transferred (and therefore released), but which have not yet been processed.
- New synchronous RFC interface
- This synchronous interface takes over from the previous asynchronous interface. Compared to the asynchronous interface, it is more simple to realize from a technical point of view. This is because the callback procedure is no longer necessary.
Effects on Existing Data
Effects on Data Transfer
Effects on System Administration
Effects on Customizing
Customizing for Model Mix Planning was enhanced with the following IMG activities:
The IMG activity Define Procedure Packages was enhanced with the following individual procedures:
- Genetic algorithm (multilines)
- This algorithm can be used to optimize a group of alternative lines. This procedure can also be used to monitor and optimize several, independent individual lines that are linked via a common product (a product with various production versions, the individual lines are entered in the iPPE access objects).
- Percentage smoothing (mixing/date)
- For this form of percentage smoothing, you define whether you want to prioritize the date desired by the customer or the even mixing of products when dispatching the orders to a line. You do this in a profile, which you define in the IMG activity Define Percentage Smoothing.
Note also the rules for combining the individual procedures with the suitable planning basis. These are described in the IMG document Define Procedure Packages
Further Information
Release Information for Restriction Maintenance in Model Mix Planning
Release Information for iPPE Line Design
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This documentation is copyright by SAP AG.
Length: 12671 Date: 20240420 Time: 101627 sap01-206 ( 216 ms )
