Rough and detailed planning in production planning - how useful is a clear separation?
The distinction between rough and detailed planning
The terms “rough planning” and “detailed planning” are widely used in production planning. But does this classic separation still make sense in times of agile and digitalized production processes? While some companies stick to this tried-and-tested concept, others argue in favor of a more flexible and dynamic approach. In this article, we examine the traditional definitions, the theoretical foundations from the scientific literature on production planning and ask the question: should we rethink the classic separation?
Theoretical principles for rough and detailed planning
According to the scientific literature on production planning, production planning and control (PPC) is regarded as a hierarchically structured system. This system is divided into various planning levels, which differ in terms of their time horizon and level of detail. A central distinction is made between tactical planning (rough planning) and operational planning (detailed planning), each of which pursues specific tasks and objectives (Schuh & Stich, 2012).
Tactical planning (rough planning): This operates on a medium-term time horizon of weeks to months and includes the following tasks (Fleischmann, 2008):
- Creation of production programs
- Material requirements planning
- Coordination of capacities to ensure a smooth production process
Operational planning (detailed planning): Operational planning concerns short-term control and fine-tuning within production on a daily or shift basis. Its tasks include (Fleischmann, 2008)
- Machine allocation
- Sequence planning
- Optimization measures for bottlenecks and set-up times for efficient production
This classification shows that tactical planning serves as a link between strategic corporate decisions and short-term operational measures. However, the classic separation between rough and detailed planning can lead to inefficient processes not being optimally coordinated. One central point of criticism, for example, is that rough planning often makes inaccurate time assumptions. For example, clever shift planning can be used to complete a set-up process in advance, which shortens the actual process time – a possibility that is often not taken into account in rough planning.
The challenges of separation in practice
Industrial practice often shows that rough and detailed planning cannot always be strictly separated. The following challenges frequently arise, particularly in dynamic production environments:
- Dynamic markets: changes in demand or short-term disruptions can make it necessary to adjust rough planning.
- Flexible production systems: With modern Industry 4.0 technologies, it is becoming increasingly difficult to maintain a rigid separation between rough and detailed planning.
- Setup time optimization: A central point of criticism of the classic separation is that rough-cut planning often makes inaccurate time assumptions. For example, clever shift planning can be used to complete a set-up process in advance, which shortens the actual process time – a possibility that is often not taken into account in rough-cut planning.
A new approach: combining tactical and operational planning
Our approach suggests making tactical and operational planning more flexible by interlinking the two levels more closely. In traditional production planning, these two levels are often considered separately, but a close connection can lead to considerable efficiency gains.
A key example of this is the consideration of set-up times:
- In classic tactical planning, a standard time of 30 minutes is scheduled for a production process (including set-up, execution, etc.)
- However, if a corresponding set-up process has already been carried out in the previous shift, the actual processing time is reduced to 10 minutes.
- This difference of 20 minutes is not reflected in the original rough planning and leads to unused capacity.
This example illustrates that tactical planning often works with default values, while operational circumstances are more flexible. A stronger link between the two planning levels could be realized through dynamic feedback mechanisms:
- Real-time data integration: sensor-based systems could continuously record production status and dynamically adjust tactical plans.
- AI-supported optimization: Algorithms that continuously learn from operational changes could be used to create more precise production plans.
- Adaptive planning horizons: Rigid weekly or monthly planning could be replaced by rolling, constantly updated planning that responds directly to short-term changes.
This type of optimization would allow production processes to be planned for the long term while maintaining flexible fine control in the short term. This would make it possible to plan production processes precisely over several months without losing agility in the event of short-term changes. Close integration of tactical and operational planning ensures more efficient use of resources and reduces unnecessary waiting times or capacity bottlenecks.
Should rough and detailed planning still be considered separately today?
The classic separation of rough and detailed planning has proven its worth in many companies, but it is increasingly reaching its limits in modern, flexible production environments. The question is: should the separation be maintained or replaced by a closer integration of tactical and operational planning? Both approaches have their justification.
Arguments in favor of dovetailing tactical and operational planning:
- Better utilization of capacities: Real-time data enables more precise planning and prevents unnecessary idle times.
- Optimized set-up processes: Set-up times can be scheduled more effectively and shortened by closely coordinating medium-term and short-term planning.
- Greater flexibility: Companies can react more quickly to changes at short notice, for example in the event of machine breakdowns or unexpected orders.
- Reduction of plan deviations: By continuously comparing planned specifications and actual production processes, more realistic decisions can be made.
Arguments in favor of the traditional model of separate rough and detailed planning:
- Clear responsibilities: By separating the planning levels, tasks and responsibilities can be clearly defined.
- Structured planning: Long-term and medium-term production strategies can be developed independently of short-term disruptions.
- Reduced planning effort: Detailed detailed planning over a long period of time can lead to increased effort without all assumptions being reliable.
- Proven systems: Many companies already have established processes and PPS systems that are based on strict separation and function efficiently.
The decision between classic separation and more integrated planning therefore depends on the individual requirements of the company. While dynamic and agile production environments can benefit from closer integration, the traditional model continues to offer advantages for more stable and long-term plannable production processes.
Conclusion: Rough and detailed planning - separate or dovetail?
Increasing digitalization and automation in production calls for new planning approaches. While the classic hierarchical separation has its advantages, it is clear that a more flexible approach with closer integration of rough and detailed planning offers a lot of optimization potential.
What do you think? Should rough and detailed planning continue to be strictly separated or do we need a more flexible approach? Share your opinion in the comments!
Sources: Schuh, G., & Stich, V. (Hrsg.). (2012). Produktionsplanung und -steuerung 1: Evolution der PPS. Springer Berlin Heidelberg. https://doi.org/10.1007/978-3-642-25423-9
Fleischmann, B. (2008). Begriffliche Grundlagen. In: Arnold, D., Isermann, H., Kuhn, A., Tempelmeier, H. und Furmans, K. (Hg.): Handbuch Logistik. (3. Aufl.). Springer
