THE PLANNING PHASE
4 shows the core
elements of planning and control and execution systems. Master
planning, including strategic, business, and sales
and operations planning, is a
function of top management. It sets the
direction and scope of the
business. Master production schedules (MPS)
must be valid, matching the
goals of master planning, and be tested for
realism by rough-cut capacity
requirements planning, ensuring that
needed resources will be
available. They drive detailed planning for
both material and capacity
requirements and provide management with a handle on detailed
operations. Execution has elements for both priority
and capacity control.
Material requirements planning (MRP) embodies manufacturing's basic
What products will be made? How many? When?
What resources are required?
Which are now available for use?
Which are now on order?
Which others are needed? How many? When?
A typical MRP format. The MPS at the top shows the
desired schedule of a product to be made. Major and subassemblies
(and other components down to raw materials) are defined by bills of
material (BOM). At each level, the basic logic is applied, indicated
here as require, have now, will get, need, and start. Unfortunately,
MRP programs use less clear and definitive terms. This powerful technique
can apply to batch production, continuous production, with rates in
each time period instead of specific orders, and even to
make-to-order. It is a part of all commercial software of
planning and control computer systems.
Capacity requirements planning has three objectives:
Determine resources needed to produce what's planned.
Initiate actions to get them.
Control production lead times.
Manufacturing has four types of capacity: that required by the MPS;
theoretical, based on time utilizing available machines, equipment,
labor; that demonstrated in actual operations; and effective, that
being utilized on items produced
and used promptly.
Sound planning with computer systems requires
input from a team of knowledgeable people in the major functions
a complete core system as just described
necessary subsystems integrated with the core to serve
accurate data with NO SIGNIFICANT errors
a short planning horizon
an agile, responsive production facility
fast, disciplined execution to serve customers' real needs.