5. Detailed scheduling & finite capacity scheduling
The role of detailed production scheduling and finite capacity planning
Visuals of detailed production scheduling in different systems
Key steps in detailed scheduling
1) Daily and hourly task assignments: break weekly production plans into daily/hourly schedules. Allocate specific tasks to machines, workstations, or employees.
2) Sequencing operations: sequence tasks to minimize changeovers, setup times, and downtime. Account for sequence-dependent setup times (e.g., cleaning or recalibrating machines between product batches)
3) Build in flexibility: for urgent orders or shifts in priorities (do this only if this happened regularly historically as well)
4) Optimize with finite capacity: identify bottlenecks and adjust schedules to avoid delays
Inputs and outputs of detailed scheduling
Inputs | Outputs |
Master production schedule (MPS) | Daily/hourly task assignments |
Machine and labor capacity | Machine and worker utilization reports |
Sequence-dependent setup time data | Optimized production sequence |
Material availability | Timeline for material issuance |
Regulatory or quality constraints | Compliance plans and quality check schedules |
Challenges in detailed scheduling
Typical examples of factors that complicate detailed scheduling:
1. Dependencies: One task in the production process can only be completed after the task before it is completed.
E.g. an insulation panel needs to be covered with foil after the production.
In this case, if there is a change needed in the production step, then the schedule for the foil-covering also needs to be adjusted.
2. Machine downtime/maintenance
Unexpected breakdowns can disrupt schedules -> as mentioned hereabove for flexibility purposes when changes in priorities arise, you might consider the amount of breakdowns based on historical cases
Proactive maintenance schedules should be considered to avoid unrealistic overloading
3. Conflicting production priorities
Trying to execute for high-priority orders when regular orders have already been scheduled and commitments have been made (it’s not just pure scheduling that is tricky but also internal communication and priority assignments)
Order changes: finite capacity scheduling can reallocate resources dynamically but may push lower-priority tasks to later slots. A new order or high-priority order might impact the schedule for days or weeks to come
Similar tasks sharing the same resources
4. Human resource constraints: employee availability, skill sets, and work hours must be factored into schedules
5. Regulatory and quality control (especially crucial in industries like pharmaceuticals and food): ensure production processes comply with legal and safety standards, including post-production checks. It is not always considered as part of detailed scheduling but if this also includes several steps and impacts the availability timeline of the product, then it’s wise to incorporate this step into the scheduling.
Example for an insulation manufacturing company
A company produces two types of insulation materials: fiberglass sheets and spray foam. See the earlier sections for the high-level production plan on a monthly/quarterly level, the master production schedule on a weekly level, and the material requirements on a weekly level based on the MRP.
Now, we’ll look deeper at the daily production scheduling for the fiberglass products.
A company produces two types of insulation materials: fiberglass sheets and spray foam. See the earlier sections for the high-level production plan on a monthly/quarterly level, the master production schedule on a weekly level, and the material requirements on a weekly level based on the MRP.
Now, we’ll look deeper at the daily production scheduling for the fiberglass products.
Inputs into the detailed production schedule:
Detailed scheduling plan for week 1 considering the finite resources
Day | SKU | Units produced | Production time (hrs) | Setup time (hrs) | Quality check (hrs) | Total time (hrs) | Notes |
Monday | FG-10mm | 21*62.5 = 1,312.5 | 21 | 2 | 1 | 24 | Start FG-10mm on M1. |
Tuesday | FG-10mm | 23*62.5 = 1,437.5 | 23 | 0 | 1 | 24 | Continue FG-10mm |
Wednesday | FG-10mm | 14*62.5 = 875 | 14 | 0 | 1 | 15 | Completion of FG-10mm weekly target |
| FG-20mm | 6*62.5 = 375 | 6 | 2 | 1 | 9 | Switch to FG-20mm. |
Thursday | FG-20mm | 23*62.5 = 1437.5 | 23 | 0 | 1 | 24 | Continue on FG-20mm |
Friday | FG-20mm | 5.8*62.5 = 362.5 | 6 | 0 | 1 | 7 | Completion of FG-20mm weekly target |
Friday | FG-30mm | 15*62.5 = 937.5
| 15 | 1 | 1 | 17 | Switch to FG-30mm |
Analysis of week 1 schedule
Machine utilization: continuously used, and 512,5 units short for FG-30mm.
This is due to the fact that set-up times and quality checks weren’t considered at the highest level of planning.
GANTT chart example for the full week: