PRODUCTION PLANNING
Rough-Cut Capacity Planning
PRODUCTION PLANNING
Rough-Cut Capacity Planning
As orders are slotted in the MPS, the effects on the
production work centers are checked
Rough cut capacity planning identifies underloading
or overloading of capacity
PRODUCTION PLANNING
Example: Rough-Cut Capacity Planning
Texprint Company makes a line of computer printers on a
produce-to-stock basis for other computer manufacturers.
Each printer requires an average of 24 labor-hours. The plant
uses a backlog of orders to allow a level-capacity aggregate
plan. This plan provides a weekly capacity of 5,000 labor-
hours.
Texprint’s rough-draft of an MPS for its printers is shown on
the next slide. Does enough capacity exist to execute the
MPS? If not, what changes do you recommend?
PRODUCTION PLANNING
Example: Rough-Cut Capacity Planning
Rough-Cut Capacity Analysis
WEEK
1 2 3 4 5 TOTAL
PRODUCTION 100 200 200 250 280 1030
LOAD 2400 4800 4800 6000 6720 24720
CAPACITY 5000 5000 5000 5000 5000 25000
UNDER or OVER LOAD 2600 200 200 1000 1720 280
PRODUCTION PLANNING
Example: Rough-Cut Capacity Planning
Rough-Cut Capacity Analysis
The plant is underloaded in the first 3 weeks (primarily
week 1) and it is overloaded in the last 2 weeks of the
schedule.
Some of the production scheduled for week 4 and 5
should be moved to week 1.
PRODUCTION PLANNING
Types of Production-Planning
and Control Systems
PRODUCTION PLANNING
Types of Production-Planning and Control Systems
Pond-Draining Systems
Push Systems
Pull Systems
Focusing on Bottlenecks
PRODUCTION PLANNING
Pond-Draining Systems
Emphasis on holding inventories (reservoirs) of
materials to support production
Little information passes through the system
As the level of inventory is drawn down, orders are
placed with the supplying operation to replenish
inventory
May lead to excessive inventories and is rather
inflexible in its ability to respond to customer needs
Production Planning
PUSH SYSTEMS
Use information about customers, suppliers, and
production to manage material flows
Flows of materials are planned and controlled by a
series of production schedules that state when batches
of each particular item should come out of each stage of
production
Can result in great reductions of raw-materials
inventories and in greater worker and process utilization
than pond-draining systems
Production Planning
PULL SYSTEMS
Look only at the next stage of production and
determine what is needed there, and produce only that
Raw materials and parts are pulled from the back of the
system toward the front where they become finished
goods
Raw-material and in-process inventories approach zero
Successful implementation requires much preparation
Production Planning
FOCUSING ON BOTTLENECKS
Bottleneck Operations
Impede production because they have less capacity
than upstream or downstream stages
Work arrives faster than it can be completed
Binding capacity constraints that control the capacity
of the system
Optimized Production Technology (OPT)
Synchronous Manufacturing
Production Planning
SYNCHRONOUS MANUFACTURING
Operations performance measured by
throughput (the rate cash is generated by sales)
inventory (money invested in inventory), and
operating expenses (money spent in converting
inventory into throughput)
Production Planning
SYNCHRONOUS MANUFACTURING
System of control based on:
drum (bottleneck establishes beat or pace for other
operations)
buffer (inventory kept before a bottleneck so it is never
idle), and
rope (information sent upstream of the bottleneck to
prevent inventory buildup and to synchronize
activities)
Production Planning
WRAP-UP: WORLD-CLASS PRACTICE
Push systems dominate and can be applied to almost
any type of production
Pull systems are growing in use. Most often applied in
repetitive manufacturing
Few companies focusing on bottlenecks to plan and
control production.
