What Is Resource Group?
Also known as: resource groups, SyteLine resources, capacity group
Definition
A resource group in SyteLine is a set of interchangeable machines, cells, or people that operations schedule against. It carries the capacity, calendar, and constraint data that APS uses to place work into finite time windows.
Resource Group Explained
Where the work center answers "what does this cost," the resource group answers "when can this actually run." A resource group defines how many units of capacity are available - three identical machining centers, two paint booths, a team of four welders - together with the shift calendar, planned downtime, and efficiency factors that determine real available hours. APS loads operations into that capacity in priority sequence and reports the resulting finite schedule.
Individual resources can be defined within the group when the distinction matters. If two of five machines can hold a tighter tolerance, modelling them as specific resources lets a routing require the capable subset while other operations use any machine in the group. This is how aerospace suppliers model qualified equipment and certified operators without creating a separate work center for every capability combination, which would fragment costing needlessly.
Calendars deserve more attention than they usually get. A resource group scheduled against a generic five-day calendar when the cell actually runs three shifts plus Saturdays will show a bottleneck that does not exist, and planners will lose confidence in the schedule within weeks. Conversely, a calendar that ignores planned maintenance and holiday shutdowns produces optimistic dates that customer service passes on to customers. Calendar accuracy is ongoing maintenance, not a one-time setup task.
The most common modelling error is treating a constrained shared resource - a heat treat oven, an inspection lab, a single skilled programmer - as unlimited because it is not a machine on the routing. If it genuinely gates throughput, model it as a resource group and put it in the routing. Otherwise APS will produce beautiful schedules that collapse the moment work reaches the real constraint, which is exactly the failure mode finite scheduling was supposed to eliminate.
Why It Matters
- Resource group capacity and calendars are the direct inputs to every APS date the business promises to a customer.
- Modelling qualified resources within a group supports certification and special-process control without fragmenting the cost model.
- Unmodelled shared constraints such as heat treat or inspection are the most common reason finite schedules fail in practice.
- Stale calendars quietly destroy planner trust, after which the schedule is ignored regardless of how good the engine is.
In Practice
Before blaming APS for bad dates, compare each resource group's calendar against the actual shift pattern and the last twelve months of downtime. In most troubled deployments at least a third of groups have calendars that no longer match reality, and correcting them fixes more schedule complaints than any parameter tuning.
Frequently Asked Questions
Do I need resource groups if I only run MRP in SyteLine?
Classic MRP plans against infinite capacity and uses fixed lead times, so it does not consume resource group capacity the way APS does. You still need work centers for costing. If you later move to APS, or want any meaningful capacity requirements planning, resource groups with accurate capacity and calendars become essential, so many sites build them correctly from the start.
How do I model a shared constraint like heat treat in SyteLine?
Create it as a resource group with realistic capacity and calendar, then include it as a routing operation on every part that passes through it, even when the work is outsourced and the operation is short. If a genuine bottleneck is not represented in the routing, APS cannot see it, and the resulting schedule will systematically over-promise on every product line that depends on it.
Related Terms
Work Center
A work center in SyteLine is the production location where a routing operation is performed. It carries the labor, machine, and overhead rates used to cost that operation and links to the resource group that APS uses for finite capacity scheduling.
APS (Advanced Planning and Scheduling)
APS (Advanced Planning and Scheduling) is SyteLine's memory-resident planning engine that schedules production against finite material and capacity constraints, producing realistic operation start and finish dates and enabling capable-to-promise responses during order entry.
Job Order
A job order in SyteLine is the production work order that authorises manufacturing a quantity of an item. It carries its own copy of the bill of material and routing, collects material, labor, and overhead costs, and moves through a defined status life cycle.
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