Operations Management

Unit 9: Managing Process Constraints

授課教師： 國立臺灣大學工商管理學系 余峻瑜 教授

本課程指定教材為 Operations Management: Processes and Supply Chains, 10th ed., Lee J. Krajewski, Larry P. Ritzman, and Manoj K Malhotra, Pearson Education, ©2013

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Case: Radcliffe InfirmaryCase: Radcliffe Infirmary

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p.263

Managing ConstraintsManaging Constraints

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Constraints

Three types of constraints Physical, Market, Managerial

Bottleneck p.264, 265

Theory of Constraints (TOC)Theory of Constraints (TOC)

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p.265

TOC and Financial MeasuresTOC and Financial Measures

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p.265 Table 7.1

Key Principles of the TOCKey Principles of the TOC

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p.266 Table 7.2

Practical Application of the TOCPractical Application of the TOC

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TOC involves the implementation of these five steps

p.266, 267

Identification and Management of Identification and Management of Bottlenecks Bottlenecks

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p.267

Throughput time

Identifying bottlenecks

EXAMPLE 7.1: Identifying the Bottleneck in EXAMPLE 7.1: Identifying the Bottleneck in a Service Processa Service Process

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p. 267

Floating BottlenecksFloating Bottlenecks

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Many front-office processes with high customer contacts and divergences have more complicated operations than the simple line flows in Ex. 7.1.

The variability in workload creates floating bottlenecks. This type of variability increases the complexity of day-to-

day scheduling.

In this situation, management prefers lower utilization rates, allowing greater slack to absorb unexpected surges in demand.

EXAMPLE 7.2: Identifying the Bottleneck in EXAMPLE 7.2: Identifying the Bottleneck in a Batch Processa Batch Process

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p.269

Managing Bottlenecks in Manufacturing Managing Bottlenecks in Manufacturing ProcessesProcesses

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Identifying bottlenecks: Note utilization.

Note setup times.

Variability in workloads may create floating bottlenecks.

Ask experienced workers and supervisors.

Look for piled up materials in front of workstations

Managing Bottlenecks in Manufacturing Managing Bottlenecks in Manufacturing ProcessesProcesses

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Relieving bottlenecks: Short-term

Carefully monitor schedules and keep bottleneck resource as busy as is practical.

Minimize idle time at the bottleneck.

Make sure bottleneck has all the resources it needs to stay busy.

Long-term Investments

More employees, more shifts, more working days

Process improvement / reengineering

Product Mix DecisionsProduct Mix Decisions

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Traditional method: Contribution margin is the amount each product

contributes to profit and overhead.

No fixed costs are considered.

Bottleneck method: Note that the firm’s actual throughput and overall

profitability depend on the contribution margin generated at the bottleneck.

EXAMPLE 7.3EXAMPLE 7.3Determining the Product MixDetermining the Product Mix

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p.270-272

Drum-Buffer-Rope SystemsDrum-Buffer-Rope Systems

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p.272, 273 Figure 7.3

Capacity constrained resource (CCR) The bottleneck schedule is the drum The buffer is the time buffer The rope represents the tying of material release to the

drum beat

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頁碼 作品 版權圖示 來源 / 作者

3Pearson Education / Lee J., Larry P. Ritzman, and Manoj K Malhotra,Operations Management: Processes and Supply Chains, 10th ed., P. 264, 265.本作品以著作權法第 46 、 52 、 65 條合理使用。瀏覽日期： 2013/05/01 。

7Pearson Education / Lee J., Larry P. Ritzman, and Manoj K Malhotra,Operations Management: Processes and Supply Chains, 10th ed., P. 266.本作品以著作權法第 46 、 52 、 65 條合理使用。瀏覽日期： 2013/05/01 。

8Pearson Education / Lee J., Larry P. Ritzman, and Manoj K Malhotra,Operations Management: Processes and Supply Chains, 10th ed., P. 267.本作品以著作權法第 46 、 52 、 65 條合理使用。瀏覽日期： 2013/05/01 。

10 臺灣大學 / 余峻瑜 教授

12 臺灣大學 / 余峻瑜 教授

13 臺灣大學 / 余峻瑜 教授

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頁碼 作品 版權圖示 來源 / 作者

14 臺灣大學 / 余峻瑜 教授

16Pearson Education / Lee J., Larry P. Ritzman, and Manoj K Malhotra,Operations Management: Processes and Supply Chains, 10th ed., P. 272.本作品以著作權法第 46 、 52 、 65 條合理使用。瀏覽日期： 2013/05/01 。

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Case: Radcliffe Infirmary... EXAMPLE 7.1: Identifying the Bottleneck in a Service Process( 各頁標題 )

Pearson Education / Lee J., Larry P. Ritzman, and Manoj K Malhotra,Operations Management: Processes and Supply Chains, 10th ed., P. 263-267.本作品以著作權法第 46 、 52 、 65 條合理使用。瀏覽日期： 2013/05/01 。

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EXAMPLE 7.2: Identifying the Bottleneck in a Batch Process

Pearson Education / Lee J., Larry P. Ritzman, and Manoj K Malhotra,Operations Management: Processes and Supply Chains, 10th ed., P. 269.本作品以著作權法第 46 、 52 、 65 條合理使用。瀏覽日期： 2013/05/01 。

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EXAMPLE 7.3Determining the Product Mix, Drum-Buffer-Rope Systems( 各頁標題 )

Pearson Education / Lee J., Larry P. Ritzman, and Manoj K Malhotra,Operations Management: Processes and Supply Chains, 10th ed., P. 270, 272.本作品以著作權法第 46 、 52 、 65 條合理使用。瀏覽日期： 2013/05/01 。

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2-9. 11, 15, 16

Pixabay/ Unknownhttp://pixabay.com/en/ashton-books-book-42701本作品屬公共領域之著作。瀏覽日期： 2013/05/01 。