Planeacion Agregada

1

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Chapter 13
Aggregate Planning

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OBJECTIVES
• Sales and Operations Planning
• The Aggregate Operations Plan
• Examples: Chase and Level strategies

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Exhibit 13.1

Process planning

Long
range

Strategic capacity planning

IntermediateForecasting
& demand
range
management

Sales and operations (aggregate) planning
Sales plan

Aggregate operations plan

Manufacturing
Services

Master scheduling
Material requirements planning

Short
range

Order scheduling

Weekly workforce and
customer scheduling
Daily workforce and customer scheduling
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Sales and OperationsPlanning Activities
• Long-range planning
–
–

Greater than one year planning horizon
Usually performed in annual increments

• Medium-range planning
–
–

Six to eighteen months
Usually with monthly or quarterly increments

• Short-range planning
–
–

One day to less than six months
Usually with weekly increments
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The AggregateOperations Plan
• Main purpose: Specify the optimal combination of
– production rate (units completed per unit of time)
– workforce level (number of workers)
– inventory on hand (inventory carried from
previous period)
• Product group or broad category (Aggregation)
• This planning is done over an intermediate-range
planning period of 6 to18 months

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Balancing Aggregate Demand
and Aggregate Production Capacity
10000

Suppose the figure to
the right represents
forecast demand in
units
Now suppose this
lower figure represents
the aggregate capacity
of the company to
meet demand

10000
8000
8000
6000

7000
6000

5500
4500

4000
2000
0
Jan

Feb

Mar

Apr

May

Jun

9000

10000

8000

8000

Whatwe want to do is
balance out the
production rate,
workforce levels, and
inventory to make
these figures match up

6000
6000

4500

4000

Jan

Feb

4000

4000
2000
0
Mar

Apr

May

Jun

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Required Inputs to the Production
Planning System
Competitors’
behavior
External
capacity

Current
physical
capacity

Rawmaterial
availability

Planning
for
production

Current
workforce

Inventory
levels

Market
demand

External
to firm

Economic
conditions

Activities
required
for
production

Internal
to firm

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Key Strategies for Meeting Demand
• Chase

• Level

• Some combination of the two
©The McGraw-Hill Companies, Inc., 2004Aggregate Planning Examples: Unit
Demand and Cost Data
Suppose we have the following unit
demand and cost information:
Demand/mo

Jan

Feb

Mar

Apr

May

Jun

4500

5500

7000

10000

8000

6000

Materials
Holding costs
Marginal cost of stockout
Hiring and training cost
Layoff costs
Labor hours required
Straight time labor cost
Beginning inventory
Productivehours/worker/day
Paid straight hrs/day

$5/unit
$1/unit per mo.
$1.25/unit per mo.
$200/worker
$250/worker
.15 hrs/unit
$8/hour
250 units
7.25
8
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Cut-and-Try Example: Determining
Straight Labor Costs and Output
Given the demand and cost information below, what
are the aggregate hours/worker/month, units/worker, anddollars/worker?
Demand/mo
Jun

Jan

Feb

Mar

4500
5500
7000
Productive hours/worker/day
6000
Paid straight hrs/day

22x8hrsx$8=$140
Jan
8
Days/mo
Hrs/worker/mo
Units/worker
$/worker

22
159.5
1063.33
$1,408

Feb
19
137.75
918.33
1,216

Apr

May

7.25x2
2

10000 8000
7.25

8

Mar
21
152.25
1015
1,344

7.25x0.15=48.33
&
Apr
May
84.33x22=1063.33 Jun...