What is Finite and Infinite Scheduling
What is Finite and Infinite Scheduling
What is finite and infinite scheduling? How it is carried
out? What is to be done for each one? What are their significance?
A D V E R T I S E M E N T
Differences between planning and scheduling, finite and
infinite
Finite Scheduling
Scheduling type within capacity planning that takes account of the capacity
loads which already exist. Finite scheduling calculates the start and finish
dates for operations in the order. It is a detailed scheduling strategy with
which you schedule orders and operations, taking into account the existing
resource load. A resource overload cannot occur.
Infinite Scheduling
A detailed scheduling strategy with which you schedule orders and operations,
without taking into account the existing resource load. It is therefore possible
for resource overloads to occur.
R/3 does planning without consideration for capacity
situations. So if MRP says you need 500 parts on 3/1/04, it schedules them all
to be built at the same time, even though you can only do 100 at a time. Assume
you have a fixed lot size of 100, you'll get 5 planned orders for 100 to start
on the same day. This is "Infinite Planning". APO would recognize that
constraint, and instead schedule out the 5 orders over time. The important part
of that is that it also will schedule out the deliveries of the components for 5
different days. This is "Finite Planning".
Now, assume old fashion MRP. It schedules all 5 orders for
the same day, and the buyers go out an get all of the components for the same
day. Then the planner realizes he can't do all 5, and manually changes the
schedule, and manually spreads out the 5 orders. The buyers will recieve
rescheduling notifications, but not until the scheduler does the manual
rescheduling.
You could call this "Infinite Scheduling", but that only means the same thing as
Infinite Planning.
But, SAP has "Capacity Leveling". What that means is you run
another program after MRP (CM27 and CM28), which can be run in batch mode
overnight. (There is a ton of configuration and thinking that will be required
to do this!). The capacity leveling program will recognize the constrant at the
work center level, and fill up the first day, then re-schedule the next
order to the next available capacity, then the next order searches for available
capacity, and so on. This is called "Finite Scheduling". The problem with this
is the opposite of Infinite Planning, which is it doesn't take Material
availablity into consideration! The system will re-schedule a production order
without thinking about whether the materials will be available
or not.
Finite Planning does Finite Scheduling at the same time. If
there is no capacity available on the desired date, the system looks for when
capacity IS available. Then it stops to see if Materials will also be available
(usually based on the lead-time for those components). If there is a material
problem, then the system figures out when the materials WILL be available, and
then
checks to see if capacity is available on THAT day, and if so, it blocks off
capacity, and allocates the materials for that day.
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