Calculating the Planning Worksheet (Running MPS/MRP)
The terms "running the planning worksheet" or "running MRP"
refer to the calculation of the master production schedule and
material requirements based on actual and forecasted demand. The
planning system can calculate either Master Planning Schedule (MPS)
or Material Requirements Planning (MRP) on request, or it can
calculate both at the same time.
MPS is defined as the calculation of a master production
schedule based on actual demand and the production forecast. The
MPS calculation is carried out for end items that have a forecast
or/and a sales order line. These items are called "MPS items" and
are identified dynamically when the calculation starts.
MRP is defined as the calculation of material requirements based
on actual demand for components and the production forecast on the
component level. The MRP is calculated only for items that are not
MPS items. The overall purpose of MRP is to provide time-phased
formal plans, by item, to supply the right item at the right time,
in the right place, in the right quantity.
The planning algorithms used for both MPS and MRP are identical.
The planning algorithms concern netting, reuse of existing
replenishment orders, and action messages. The planning system
process looks at what is needed or will be needed (demand) and what
is on-hand or expected (supply.) When these quantities are netted
against each other, the program provides Action Messages. Action
messages are suggestions to create a new order, change an order
(quantity or date), or cancel an order in order. The term "order"
includes production orders, purchase orders, and transfer
orders.
Proper planning results depend on the set up done on Item Cards,
Production BOMs, and Routings.
Methods for Generating a Plan
Most companies have a specific process for generating a
production plan, including the periodic requirements for plan
generation; that is, how often, what method, and so on. These
processes should be considered during the setup and implementation
stage. Plans may be calculated in three ways:
Calculate Regenerative
Plan: This function processes or regenerates the entire
material plan. This process starts by deleting all planned orders
currently loaded. All items in the database are replanned.
Calculate Net Change
Plan: This function processes a net change plan. Items are
considered in net change planning as a result of two types of
changes:
Demand/supply changes: These include modifications to quantities
on sales orders, production forecasts, production orders, or
purchase orders. An unplanned inventory level change is also
considered a quantity change.
Planning parameter changes: These include changes in safety
stock, reorder point, routing, bill of material, and changes to the
reorder cycle or lead time calculation.
Get Action Messages: This
function serves as a short-term planning tool by issuing action
messages to alert the user of any modifications made since the last
regenerative or net change plan was calculated.
With each planned method, the program generates worksheet
entries assuming infinite capacity; work center and machine center
capacity is not considered when developing schedules.
Attention
The Regenerative Plan is the most common
process used for running MRP. The calculate planning worksheet and
carry out action messages processes, however, can be used to run
the Calculate Net Change Plan.
The Get Action Messages Plan can be run
between net change and regenerative planning runs to get an
immediate view of the impact of schedule changes, but it is not
intended as a replacement of net change or regenerative
planning.
To Calculate the Planning Worksheet:
The calculation of a materials plan is performed as follows:
Open the Planning Worksheet window.
This window is used for Regenerative/Net change planning and
MPS/MRP.
Click Functions,
Calculate Regenerative
Plan.
On the Item tab you can filter
and run the planning routines based on item, item description or
location.
The Options tab allows you to
specify the type and horizon of the planning run:
Placing a check mark in this field
initiates the calculation of a master production schedule. Items
with open sales orders and/or production forecasts are considered
in this run.
Placing a check mark in this field
initiates the calculation of material requirements planning. Items
with dependent requirements are considered in this run.
Typically, MPS and MRP are run simultaneously. To run MPS and
MRP simultaneously, the Combined
MPS/MRP Calculation check box must be checked on the
Planning tab of the
Manufacturing Setup window.
This date is used to evaluate
inventory availability. If an item's on-hand quantity is below the
reorder point, the system forward-schedules a replenishment order
from this date. If an item is below its safety stock (as of the
order date), the system back-schedules a replenishment order due on
the order date.
This is the ending date of the
planning horizon. Neither demand nor supply is considered after
this date. If the reorder cycle for an item extends beyond the
ending date, the effective planning horizon for that item is equal
to the Order Date +
Reorder Cycle.
The planning horizon is the amount of
time the plan is extended to. If the horizon is too short, items
with a longer lead time are not ordered on time. If the horizon is
too long, too much time is spent reviewing and processing
information that likely changes before it is needed. It is possible
to set one planning horizon for production and a longer one for
purchases, although it is not required. A planning horizon for
purchases and production should be set to cover the cumulative lead
time for components.
If you place a check mark in this field, the planning run will stop
as soon as it encounters an error. At the same time, a message is
displayed with information about the (first) error. If an error
exists, only the successful planning lines made before the error
was encountered will be presented in the planning worksheet.
If you leave the field unchecked, the
Calculate Plan batch job will continue until it has completed, that
is, errors will not interrupt the batch job. If one or more errors
exist, the program will display a message after completion saying
how many items are affected. The Planning Error Log window will then open to
provide more details about the error and links to the affected item
card(s).
In this field you select a forecast
that should be included as demand when running the planning batch
job. The default forecast is set up on the Planning tab of the Manufacturing Setup window.
In this field you define how much of
the selected forecast to include in the planning run by entering a
date before which forecast demand is not included, thus allowing
you to exclude old information.
Click OK. The batch job runs
and then the planning worksheet is populated with the planning
lines. For help on a specific field, click in the field and press
F1.
Action Messages
Action messages are issued by the order tracking system when
balance is unattainable within the existing order network. They can
be viewed as a suggestion for you to process changes that
reestablish equilibrium between supply and demand.
The generation of action messages occurs one level at a time, with
respect to each item's low-level code. This ensures that all items
that experience or will experience changes in supply or demand are
considered.
To avoid small, superfluous or unimportant action messages, the
user can establish dampeners, which serve to restrict the
generation of action messages to only those changes that exceed the
defined quantity or number of days.
In response to any supply/demand imbalances, the program generates
the following action messages:
If a demand cannot be fulfilled by
suggesting action messages to Change Qty., Reschedule, or
Reschedule & Change on existing orders, the system generates
Action Message = New, which suggests a new order. In addition, the
system issues action message New if there are no existing supply
orders within the reorder cycle of the item in question. This
parameter determines the number of periods forward and backward in
the availability profile when searching for an order to
reschedule.
When demand that is tracked to a
supply order(s) experiences a quantity change, the system generates
Action Message = Change Qty., which indicates that the related
supply should be changed relative to the change in demand. If a new
demand emerges, the system searches for the nearest existing
unreserved supply order within the reorder cycle, and issues a
Change Action Message for that order.
When a supply or demand order
experiences a date modification causing an imbalance in the order
network, the system issues Action Message = Reschedule. If there is
a one-to-one relationship between demand and supply, the system
issues an action message suggesting that the supply order be moved
accordingly. If the supply-order covers demand from more than one
sales order, the supply order is re-scheduled equal to the date of
the first demand.
If both the dates and quantities of
an order have been modified, it is necessary to change plans with
regard to both circumstances. Action messaging gathers both actions
in one message, Resched. and Chg. Qty., to ensure that the order
network returns to balance.
If a demand, which has been covered
on an order-to-order basis, is deleted, the system issues an Action
Message to Cancel the related supply order(s). If the relationship
is not order-to-order, the system generates an action message to
Change in order to reduce the supply. If through other factors,
such as inventory adjustments, a supply order is not required at
the time the action messages are generated by the user, the system
suggests Action Message = Cancel in the worksheet.
Note
An Action Message is a suggestion to create a
new order, cancel an order, or change the quantity or date of an
order. An order is a purchase order, transfer order, or production
order.
To Carry Out Action Messages:
Once you have reviewed the action messages and determined
whether to accept some or all of the suggested changes – by
checking or unchecking the Accept
Action Message field – you are ready to update the schedules
accordingly.
On the calculated Planning Worksheet, click Functions, Carry Out Action Message. The Carry Out Action Msg. - Plan. batch
job has two tabs: Planning Line and Options.
On the Planning Line tab you
can set filters to limit the carry out action messages.
On the Options tab, you
choose which types of orders you want to create and whether lines
need to be moved to the Requisition Worksheet:
In this field, you can specify
whether you want to create production orders in the Manufacturing
application area. You can do this directly from the planning line
proposals. You can create either planned or firm planned production
orders.
In this field, you can specify
whether you want to create purchase orders in the Purchases &
Payables application area. You can do this directly from the
planning line proposals.
If you have chosen to copy the
planning line proposals for purchase orders to the requisition
worksheet, this field becomes editable. You can select the template
name here.
If you have chosen to copy the
planning line proposals for purchase orders to the requisition
worksheet, this field becomes editable. You can select the
worksheet name here.
In this field, you can specify
whether you want to create transfer orders in the Inventory
application area. You can do this directly from the planning line
proposals.
If you have chosen to copy the
planning line proposals for transfer orders to the requisition
worksheet, this field becomes editable. You can select the template
name here.
If you have chosen to copy the
planning line proposals for transfer orders to the requisition
worksheet, this field becomes editable. You can select the
worksheet name here.
If you place a check mark in this
field, the Carry Out Action Msg. -
Plan. batch job will stop as soon as it encounters an error.
At the same time, a message is displayed with information about the
(first) error. If an error exists, only the planning lines
processed before the error was encountered will result in supply
orders.
If you leave the field unchecked, the Carry Out Action Msg. - Plan. batch job
will continue until it has completed, that is, errors will not
interrupt the batch job. If one or more errors exist, the program
will display a message after completion saying how many items are
affected.
Click OK.
The batch job deletes the lines in the planning worksheet after
it has performed the action message. The other lines remain in the
planning worksheet until they are either accepted at a later date
or else deleted. You can also delete the lines manually.
Quick guides for manufacturing are available in
a document that you can edit and print in Microsoft Office Word.
The file, called Quick Guides – Manufacturing Foundation -
Classic.doc, is installed in the documentation folder of your
client installation.