GlossaryKind of term: Manufacturing termCapacity planning
What is capacity planning?
Capacity planning sets the hours orders need against the hours available, per machine, work centre and period, so you can see where the bottlenecks are.
Capacity planning compares required capacity with available capacity, per resource and per period. Resources are machines, work centres and people such as operators and programmers. Demand comes from firm orders and, if you choose, from quotes still outstanding. Supply is the hours a resource can work under its shift pattern, after maintenance and expected losses. The result shows where load exceeds supply, often at one machine or one skill.
What does capacity planning depend on?
The result depends on the data behind it: setup time and cycle time per operation, the route per part, the shift pattern per resource and the factor you apply to available hours for breakdowns and slow running. Infinite capacity planning loads orders on their requested date and shows where overload arises; finite planning pushes work into the next free period. A rough-cut plan per week and machine group looks further ahead; a detailed plan per machine and day is more precise but holds for a shorter time. Subcontracted work such as hardening or anodising does not load your own machines, but it does add to the order's lead time, and it often still needs your own handling, incoming inspection or a finishing step once it comes back.
How does capacity planning work in practice?
A lead time on a quote is only well founded if it takes account of free capacity on the machines along its route, alongside material and subcontracting. One extra order can push others back. If the machine on the preferred route is full, another route may deliver sooner, for example more setups on a 3-axis machine instead of fewer on a 5-axis, with a different cost estimate. Which route you choose depends on lead time, cost and the risk of deviations between setups.
What is capacity planning often confused with?
Capacity planning is not scheduling: the schedule decides which order goes on which machine when, capacity planning whether the total per period fits. Utilisation is something else again: as a measure it usually looks back at what share of available time went on orders, while the plan looks forward with the expected load.
Frequently asked questions
Should capacity be part of a quote?
In the lead time, yes. The price follows from route, times and rates; the lead time also depends on free capacity on the machines along the route, on material and on subcontracting. If a machine is full, another route can deliver sooner.
What is the difference between finite and infinite capacity planning?
Infinite planning puts every order on its requested date and shows where a resource is overloaded. Finite planning respects available hours and pushes work into the next free period. The first shows the bottlenecks, the second a feasible plan.
Does subcontracted work count in capacity planning?
Not in your own machine hours, but it does in lead time. Hardening, anodising or coating carry the supplier's lead time and sometimes a fixed shipping cycle. Include them in the order's plan, or the promised delivery date has no basis.