Scheduling, the great forgotten function of planning tools
Imagine a strategist leading troops without the tactical sense to adapt the strategy to the context on the ground. The situation is similar when a planner delivers his production plan and leaves the workshops without a short-termscheduling tool.
What is scheduling?
It is the coordination of the necessary means (human resources, machines, components, etc.) for the realisation of the production plan which defines an optimal sequence of the different operations.
How do you recognise a lack of scheduling?
Chronic delivery delays, ongoing stress on the shop floor, high levels of idle work-in-process, and the inability to prioritise emergencies from start to finish. Successful scheduling reduces cycle times, thereby reducing WIP volumes and shortening delivery times. Tréso BFR
Why is scheduling an issue that goes beyond the workshop?
The quality of scheduling depends on good communication between the Production department and the support services (Purchasing, Methods, Quality, Maintenance, etc.). Supply delays, the quality of work instructions, the rework process and breakdowns are all incidents that will penalise scheduling. The search for efficiency at all costs (illustrated by disproportionate batch sizes) is also penalising.
What are the prerequisites for successful scheduling?
Successful scheduling is only possible if:
- Capacities have been regularly sized to avoid chronic bottlenecks (through investment choices that favour resource versatility over hyper specialisation) and if the production plan has been established in “finite capacity” mode (even if the theoretical capacity is always a matter for discussion)
- Suppliers are able to supply within the expected timeframe and to the expected quality level
- • The manufacturing processes are sufficiently robust to meet the time schedules and the desired level of quality
Is orderliness a utopian goal?
No, but it requires a pragmatic approach to continuous improvement and a scheduling tool that integrates all these dimensions:
- Effective communication between Production and Support departments in the event of hazards
- Fine analysis of these hazards to build continuous improvement plans based on precise statistics
- Analysis of rejects and rework according to a catalogue of defects adapted to each workshop
- Analysis of time differences
- Analysis of real loads (on real work in progress) and not theoretical (on planned dates)
- Evolution of average waiting times and the number of dormant operations
- Measurement of the punctuality of production orders
- Projection of deliverable quantities over the month
How to set an optimal running order?
The deterministic method proposed by the market planning tools (GANTT) is often considered too centralising and unrealistic by the teams on the ground. There are several other more pragmatic methods which aim to:
- Be flexible to incorporate emergencies not foreseen at the time of planning
- Take into account the interdependencies specific to the machinery or the specific skills of each operator.
The principle consists of trusting the intelligence of the teams in the field and applying the same prioritisation rule to all operations: first in first out, shortest operation to be carried out first, delivery time of the production orders, critical ratio, priority to the shortest queue, etc. Each has its advantages and disadvantages, but they perform better than the deterministic method in general when hazards are frequent. The choice must be made according to your objectives: meeting deadlines, equipment saturation, reduction of work-in-process values, etc.
We can help you establish a free diagnosis of your scheduling process and give you our recommendations. Contact us.