What Is Infinite Capacity Planning?

Infinite capacity planning is material requirements planning that calculates what to make or buy and when, without checking whether the machines and work centers actually have the hours to do it. It explodes a bill of materials through every level, nets gross demand against on-hand inventory and open orders, and offsets each result by lead time to propose planned make or buy orders. It answers the question of what is needed and roughly when, on the deliberate assumption that capacity is unlimited. It is the classic MRP layer, and it is only half of a complete plan: the other half is a finite scheduler that reconciles those needs with real machine load.

This entry defines infinite capacity planning and shows how it relates to the finite engine inside EDGEBIC by User Solutions. For the wider index of planning terms, see the manufacturing glossary, and for its opposite, read what is finite capacity planning.

How it works

The mental picture is planning a dinner party by listing the groceries you need, without ever checking whether your oven is big enough to cook everything at once. The shopping list is correct: you truly need those ingredients. What the list ignores is whether the kitchen can physically produce all the dishes on time. Infinite capacity planning is that shopping list for the whole plant.

Mechanically, it works backward from demand. Given a need for a finished product by a date, it reads the bill of materials to find the components, subtracts what is already on hand or on order to get the net requirement, and offsets each level by its lead time so orders are placed early enough. The result is a set of planned orders: make this sub-assembly by Tuesday, buy that raw material by Wednesday. At no point does it ask whether the machines that will make those items are free.

That omission is intentional. MRP is built to run quickly across thousands of parts and many levels, and it stays fast precisely because it does not simulate machine load. The capacity question is answered later, by a separate scheduling pass. Infinite capacity planning gets the quantities and the rough timing right; a finite scheduler then makes the timing runnable.

A concrete example

Suppose you need 100 bicycles by Friday. Infinite capacity planning explodes the bicycle bill of materials: each bike needs two tires, one frame, and one set of handlebars. It nets against stock, say 40 tires already on hand, so the net requirement is 160 tires. It offsets by the tire lead time and proposes a planned order for 160 tires due Wednesday, along with planned orders for the frames and handlebars on their own lead times.

Every one of those numbers is correct as a material statement. What the calculation never checked is whether the wheel-build station has enough hours between now and Wednesday to lace 160 wheels, or whether the frame line is already full. On paper the plan looks feasible. On the floor it may not be, because two jobs cannot run on the same machine at the same time. That gap between the paper plan and the runnable plan is exactly what a finite scheduler exists to close.

How EDGEBIC uses it

EDGEBIC treats the material calculation and the capacity calculation as two cooperating layers. The planning side projects inventory forward bucket by bucket, netting gross requirements against on-hand stock and scheduled receipts to produce net requirements and replenishment suggestions. That layer is infinite capacity in spirit: it sizes what needs to be built and when it is needed, without yet worrying about machine hours.

The scheduling engine is where finite capacity takes over. When a manufacturing order is scheduled, the engine places each routing operation on a real work center at a real time, refusing to book more hours than the shift capacity actually offers and walking forward day by day until room exists. So the promised completion dates reflect the true queue in front of every machine, not an assumption of unlimited hours. The two layers hand off cleanly: the planning side answers how much and when it is needed, and the finite engine answers when it can actually be done.

This split is why an infinite-capacity number should never be quoted to a customer as a promise on its own. The netting run tells you the quantity; the finite schedule tells you the date. To see the layer that makes those dates real, read what is finite capacity planning. For the netted quantity the planning layer produces, see what is a net requirement in MRP. And for the closed-loop layer that adds capacity checks and feedback on top of MRP, read what is manufacturing resource planning (MRP II).