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Production scheduling provides the sequence of production which manufacturing and operations teams should follow to best serve the customer. Some manufacturing environments (continuous or repetitive manufacturing) might be more concerned with the rate per hour, while other schedules might be driven by product mix and changeover on a work center. The key considerations for effective production scheduling consider production goals, operational constraints, adaptability, and technology available to support the production schedule.

Setting production goals and targets

If you are a production scheduler, make the production schedule itself as simple as possible. Avoid spending much time on setting goals; instead, let the production schedule set the goals for you. Whether you are adjusting run rates on the asset at certain dates and times or scheduling batches of production, the these be the targets. In your communication with operations teams executing the schedule, these must be clearly visible in the schedule which allows for cognitive offloading.

Identifying constraints and bottlenecks

The big callout here is the Theory of Constraints (TOC). Recommended reading is The Goal by Eliyahu M. Goldratt and Jeff Cox. The audiobook is very well narrated.

When faced with a situation where you need to start or finish a production campaign or adjust a production rate by a certain date or time, let that set the standard for your approach to other aspects of production scheduling. Flex your other production in order to meet the deadline and set expectations with customers through your product team.

Likewise (and heavily emphasized in the recommended reading above) is the subordination of other processes to the bottleneck process. I have needed to subordinate to bottleneck processes many times throughout my career. Some questions to ask if the bottleneck process is not obvious:

• If I need more product but something within my operation is holding me back, what is that other process holding me back?
• Which process today has the slowest throughput rate?
• Which process today has the worst prime yield rate (production of good material)?
• Where is inventory building up? What work center is the next work center to process that material?

Managing changes and disruptions

Times when the production schedule gets disrupted or changed can be extremely stressful. How you respond to the disruption can have a ripple or bullwhip effect through the supply chain, and such actions can have noticeable effects for several days, weeks, or months after the disruption is resolved.

In most manufacturing environments, your production timeline or horizon can best be expressed as the frozen, slushy, and liquid zones. The below visual is an example with time periods in weekly buckets:

• Frozen: no changes allowed or only with manufacturing and operations approval.
• Material has already been delivered and planned to support production during this time. Changes within this zone can be costly, especially if expensive raw materials need to be held longer due to the change. Sometimes, expedites to support the change cannot be made.
• Slushy: changes to the schedule can be made depending on the product, but this is when materials are being ordered. Such changes should be carefully evaluated.
• Liquid: changes can be made freely in this zone. This is where most of the production planning and sequencing actually occurs. Once the sequencing is done in this zone, it is allowed to roll into the slushy and frozen zones mostly untouched.

Utilizing technology and data

Your ability to effectively manage the production schedule can be greatly enhanced if your organization utilizes an ERP system which includes an Advanced Planning and Scheduling (APS) component, or you use bolt-on software to execute this.

In SAP, this is accomplished via any graphical capacity management transaction code, such as CM21, CM25, or CM29. Scheduling of batch manufacturing is accomplished through simple drag-and-drop of capacity requirements from the order pool to the work center, or orders already dispatched to the work center can be rearranged without the need to move back to the order pool. It is also worth exploring if your ERP supports ways to automate certain aspects of production sequencing, such as taking into consideration product wheel planning for environments which follow Fixed Sequence, Variable Volume (FSVV) production plans (recommended reading: Liquid Lean: Developing Lean Culture in the Process Industries by Raymond C. Floyd).

Unfortunately, in many ERP implementation, this level of detailed scheduling is often forgotten due to budget and time constraints of the implementation project. You might be on your own to explore your ERPs solutions for detailed production scheduling using a Gantt chart. I can guarantee you the efforts are well worth it and implementing these features will help your team and organization achieve the next level of operational excellence.

Conclusion

Perhaps you were looking for a cookie cutter answer, but there are many variables to consider when optimizing a production schedule. How you schedule depends on your manufacturing environment (and there are others which I did not mention in this post), your bottlenecks, understanding of fundamental supply chain concepts, and resources available to make production scheduling easier.

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