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McGraw-Hill/Irwin ©2009 The McGraw-Hill Companies, All Rights Reserved

1-2McGraw-Hill/Irwin ©2009 The McGraw-Hill Companies, All Rights Reserved

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Chapter 6

Capacity Planning

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• Strategic Capacity Planning Defined• Capacity Utilization & Best Operating

Level• Economies & Diseconomies of Scale• The Experience Curve• Capacity Focus, Flexibility & Planning• Determining Capacity Requirements• Decision Trees• Capacity Utilization & Service Quality

OBJECTIVES

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Strategic Capacity Planning

• Capacity can be defined as the ability to hold, receive, store, or accommodate

• Strategic capacity planning is an approach for determining the overall capacity level of capital intensive resources, including:

facilities, equipment, and overall labor force size

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Capacity Utilization

Where

Capacity usedrate of output actually achieved

Best operating levelcapacity for which the process was designed

level operating Best

usedCapacity rate nutilizatioCapacity

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Best Operating Level

Example: Engineers design engines and assembly lines to operate at an ideal or “best operating level” to maximize output and minimize ware

Example: Engineers design engines and assembly lines to operate at an ideal or “best operating level” to maximize output and minimize ware

Underutilization

Best OperatingLevel

Averageunit costof output

Volume

Overutilization

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Example of Capacity Utilization

• During one week of production, a plant produced 83 units of a product. Its historic highest or best utilization recorded was 120 units per week. What is this plant’s capacity utilization rate?

• During one week of production, a plant produced 83 units of a product. Its historic highest or best utilization recorded was 120 units per week. What is this plant’s capacity utilization rate?

Answer: Capacity utilization rate = Capacity used .

Best operating level = 83/120 =0.69 or 69%

Answer: Capacity utilization rate = Capacity used .

Best operating level = 83/120 =0.69 or 69%

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Economies & Diseconomies of Scale

100-unitplant

200-unitplant 300-unit

plant

400-unitplant

Volume

Averageunit costof output

Economies of Scale and the Learning Curve workingEconomies of Scale and the Learning Curve working

Diseconomies of Scale start workingDiseconomies of Scale start working

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The Learning Curve

As plants produce more products, they gain experience in the best production methods and reduce their costs per unit

As plants produce more products, they gain experience in the best production methods and reduce their costs per unit

Total accumulated production of units

Cost orpriceper unit

Yesterday

Today

Tomorrow

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Capacity Flexibility• Flexible plants: having the ability to rapidly

increase or decrease production levels, or to switch production capacity quickly from one product to another.

- Ultimate is zero-change over time (movable equipment)

• Flexible processes: FMS. Rapid low-cost switching from one product line to another.

• Flexible workers: multiple skills and the ability to switch form one kind of task to another.

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Capacity Planning: Balance

Stage 1 Stage 2 Stage 3Unitsper

month6,000 7,000 5,000

Unbalanced stages of productionUnbalanced stages of production

Stage 1 Stage 2 Stage 3Unitsper

month6,000 6,000 6,000

Balanced stages of productionBalanced stages of production

Maintaining System Balance: Output of one stage is the exact input requirements for the next stage

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Capacity Planning …

• Frequency of Capacity Additions: cost of upgrading too frequently and too infrequently (training)

External Sources of Capacity : Sometimes shipper (outsourcing and sharing capacity)

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Determining Capacity Requirements

Address the demands for:

individual product, individual plant capabilities, and allocation of production throughout the network.

1. Forecast sales within each individual product line

2. Calculate equipment and labor requirements to meet the forecasts

3. Project equipment and labor availability over the planning horizon

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Example of Capacity Requirements : Equipment and Labor Requirements

Year: 1 2 3 4Small (000s) 150 170 200 240Family (000s) 115 140 170 200

•Three 100,000 units-per-year machines are available for small-bottle production. Two operators required per machine.

•Two 120,000 units-per-year machines are available for family-sized-bottle production. Three operators required per machine.

Year: 1 2 3 4Small (000s) 150 170 200 240Family (000s) 115 140 170 200

Small Mach. Cap. 300,000 Labor 6Family-size Mach. Cap. 240,000 Labor 6

Small

Percent capacity used 50.00%Machine requirement 1.50Labor requirement 3.00Family-size

Percent capacity used 47.92%Machine requirement 0.96Labor requirement 2.88

Question: What are the Year 1 values for capacity, machine, and labor?

Question: What are the Year 1 values for capacity, machine, and labor?

150,000/300,000=50%

At 2 operators for 100,000, it takes 3 operators for 150,000

At 1 machine for 100,000, it takes 1.5 machines for 150,000

©The McGraw-Hill Companies, Inc., 2004

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Year: 1 2 3 4Small (000s) 150 170 200 240Family (000s) 115 140 170 200

Small Mach. Cap. 300,000 Labor 6Family-size Mach. Cap. 240,000 Labor 6

Small

Percent capacity used 50.00%Machine requirement 1.50Labor requirement 3.00Family-size

Percent capacity used 47.92%Machine requirement 0.96Labor requirement 2.88

Question: What are the values for columns 2, 3 and 4 in the table below?Question: What are the values for columns 2, 3 and 4 in the table below?

56.67%1.703.40

58.33%1.173.50

66.67%2.004.00

70.83%1.424.25

80.00%2.404.80

83.33%1.675.00

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©The McGraw-Hill Companies, Inc., 2004

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Example of a Decision Tree Problem

A glass factory specializing in crystal is experiencing a substantial backlog, and the firm's management is considering three courses of action:

A) Arrange for subcontractingB) Construct new facilitiesC) Do nothing (no change)

The correct choice depends largely upon demand, which may be low, medium, or high. By consensus, management estimates the respective demand probabilities as 0.1, 0.5, and 0.4.

A glass factory specializing in crystal is experiencing a substantial backlog, and the firm's management is considering three courses of action:

A) Arrange for subcontractingB) Construct new facilitiesC) Do nothing (no change)

The correct choice depends largely upon demand, which may be low, medium, or high. By consensus, management estimates the respective demand probabilities as 0.1, 0.5, and 0.4.

Sequence of steps in a problem and the conditions and consequences of each step.

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Example of a Decision Tree Problem (Continued): The Payoff Table

0.1 0.5 0.4Low Medium High

A 10 50 90B -120 25 200C 20 40 60

The management also estimates the profits when choosing from the three alternatives (A, B, and C) under the differing probable levels of demand. These profits, in thousands of dollars are presented in the table below:

The management also estimates the profits when choosing from the three alternatives (A, B, and C) under the differing probable levels of demand. These profits, in thousands of dollars are presented in the table below:

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Example of a Decision Tree Problem (Continued): Step 1. We start by drawing the three decisions

A

B

C

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Example of Decision Tree Problem (Continued): Step 2. Add our possible states of nature, probabilities, and payoffs

A

B

C

High demand (0.4)

Medium demand (0.5)

Low demand (0.1)

$90k$50k

$10k

High demand (0.4)

Medium demand (0.5)

Low demand (0.1)

$200k$25k

-$120k

High demand (0.4)

Medium demand (0.5)

Low demand (0.1)

$60k$40k

$20k

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Example of Decision Tree Problem (Continued): Step 3. Determine the expected value of each decision

High demand (0.4)High demand (0.4)

Medium demand (0.5)Medium demand (0.5)

Low demand (0.1)Low demand (0.1)

AA

$90k$90k

$50k$50k

$10k$10k

EVA=0.4(90)+0.5(50)+0.1(10)=$62kEVA=0.4(90)+0.5(50)+0.1(10)=$62k

$62k$62k

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Example of Decision Tree Problem (Continued): Step 4. Make decision

High demand (0.4)

Medium demand (0.5)

Low demand (0.1)

High demand (0.4)

Medium demand (0.5)

Low demand (0.1)

A

B

CHigh demand (0.4)

Medium demand (0.5)

Low demand (0.1)

$90k$50k

$10k

$200k$25k

-$120k

$60k$40k

$20k

$62k

$80.5k

$46k

Alternative B generates the greatest expected profit, so our choice is B or to construct a new facility

Alternative B generates the greatest expected profit, so our choice is B or to construct a new facility

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Planning Service Capacity vs. Manufacturing Capacity

• Time: Services can not be stored for later use and capacity must be available to provide a service when it is needed

• Location: Service capacity must be at the customer demand point and capacity must be located near the customer

• Volatility of Demand: Much greater than in manufacturing

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Service Utilization and Service Quality

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Capacity Utilization & Service Quality

• Best operating point is near 70% of capacity

• From 70% to 100% of service capacity, what do you think happens to service quality?

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Question Bowl

The objective of Strategic Capacity Planning is to provide an approach for determining the overall capacity level of which of the following?

a. Facilitiesb. Equipmentc. Labor force sized. All of the abovee. None of the above

Answer: d. All of the above

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Question Bowl

To improve the Capacity Utilization Rate we can do which of the following?

a. Reduce “capacity used”b. Increase “capacity used”c. Increase “best operating level”d. All of the abovee. None of the above

Answer: b. Increase “capacity used” (This increases the numerator in the Capacity Utilization Rate ratio, which is desirable.)

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Question Bowl

When we talk about Capacity Flexibility which of the following types of flexibility are included?

a. Plantsb. Processesc. Workersd. All of the abovee. None of the above

Answer: d. All of the above

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Question Bowl

When adding capacity to existing operations which of the following are considerations that should be included in the planning effort?

a. Maintaining system balanceb. Frequency of additionsc. External sources d. All of the abovee. None of the above

Answer: d. All of the above

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Question Bowl

Which of the following is a term used to describe the difference between projected capacity requirements and the actual capacity requirements?

a. Capacity cushionb. Capacity utilizationc. Capacity utilization rated. All of the abovee. None of the above

Answer: a. Capacity cushion

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Question Bowl

In determining capacity requirements we must do which of the following?

a. Address the demands for individual product lines

b. Address the demands for individual plants

c. Allocate production throughout the plant network

d. All of the abovee. None of the above

Answer: d. All of the above

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Question Bowl

In a Decision Tree problem used to evaluate capacity alternatives we need which of the following as prerequisite information?

a. Expect values of payoffsb. Payoff valuesc. A treed. All of the abovee. None of the above Answer: b. Payoff

values (Expected values are what is computed, not prerequisite to the analysis.)

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End of Chapter 5