(3-4 min read)
During scheduling solution implementations, we often come across capacity constraints which have either multiple dimensions or multiple capacities. Here we will provide a high-level overview about such constraints and discuss potential solutions.
In case of manufacturing industries where furnaces are used, they are available for certain time period as well as have a defined size (volume). The furnaces are required to be run in specific predefined cycles (duration), through grouping of different orders. The duration of heating is having no dependency with volume of products; however, volume is an additional hard constraint. The combination of the products should be made in such a way that it does not exceed the furnace capacity (of volume) at the same time respecting the duration. These are scenarios of having multidimensional constraints, namely, Volume and Time.
The above is an example showing two products A and B. They both have a different lot size (volume), but they must be processed for the same duration of time respecting the furnace volume.
The other scenario is when you have capacities wherein activities can be executed simultaneously thus helping in achieving the output in a lesser time (duration).
The above diagram illustrates, the relationship between simultaneous activities and the effect on the duration.
Scenario 1 - Business requirement example
We have a chiller, and you can perform up to 4 activities simultaneously. In such cases we can work with a multi-activity resource. We can define the distribution to the capacity of the resource, and in this case the capacity consumption can be managed through number of splits. Please find herewith a schematic flow of the process through which this kind of requirement can be handled.
Scenario 1 - SAP screen walk-through
In this example we have taken a work center named as chiller, and modeled the scenario.
Step-1 Parameters maintained Capacity in work center
Step-2 Operation in Routing
Maintain the number of splits
In PP/DS, the PDS looks like below. At mode level you can observe that the machine activity which was 1 Hr = 3600 secs in routing, based on number of splits it has been adjusted to 900 S. Similarly, the Capacity requirements fixed consumption is updated with 4.
This means that when the planned order is created, the duration is calculated appropriately:
Scenario 2 - Business requirement example
In a typical furnace, the orders for multiple products are loaded and emptied at once. They need to be combined with products of the same duration and temperature, but with different volumes. Care should be taken that this parameter is not overwritten when the PDS is transferred. As shown in the below example, you can fill the furnace with 6 products of type B or two products of type A, which needs to be maintained at a temperature of 24◦C.
Figure 1: Courtesy of Supply Chain Management with APO - Dickersberg
The resource should be able to handle multiple orders of different products at the same time, at the same time as respecting the volume inside the furnace. This is observed typically in heat treatment operations, such as Sintering or Coating. Please find herewith a schematic flow of the process through which this kind of requirement can be handled.
Scenario 2 - SAP screen walk-through
In work center, the capacity view has the below parameters
Once it is moved into PP/DS we can change the capacity value as shown below, representing the volumetric capacity. Thus, there are both dimensions: time and volume.
For this scenario, we will be using the variable capacity consumption. The duration must be fixed. The value of the variable capacity consumption needs to be derived through a relevant logic and needs to be applied in the PDS BAdI, enabling it to be populated in the relevant capacity requirements fields of the PDS.
Once the Orders get created and scheduled, they are stacked one above the other, but this does not mean that these are not finitely planned. The orders are validated against the furnace volume adhering to the due dates, and are processed together.
The above illustration shows potential models of how to model production processes for examples where multiple constraints needs to be considered, and at the same time orders need to be finitely planned in detail using PP/DS. Olivehorse consulting services specialise in solving complex SAP supply chain planning challenges. Please contact us on how we can help in solving your scheduling challenges.
Olivehorse Consulting Services specialise in solving complex SAP supply chain planning challenges. Please contact us for more examples of best practise in PPDS and how we can help.
Sasibhushan Padmanabhan is a Senior SCM consultant. In total, he has 17 years of manufacturing and IT experience. SAP certified in the areas of S/4 Hana Production Planning and Manufacturing, SAP IBP, SAP-ARIBA Supply Chain Collaboration(SCC).