tailieunhanh - Lecture Operations management: Chapter 7S - William J. Stevenson

Chapter 7S - Learning curves. After studying this chapter you will be able to: Explain the concept of a learning curve, make time estimates based on learning curves, list and briefly describe some of the main applications of learning curves, outline some of the cautions and criticisms of learning curves, estimate learning rates from data on job times. | Learning Curves Supplement 7 Copyright © 2015 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education. 1 Supplement 7: Learning Objectives You should be able to: LO Explain the concept of a learning curve LO Make time estimates based on learning curves LO List and briefly describe some of the main applications of learning curves LO Outline some of the cautions and criticisms of learning curves LO Estimate learning rates from data on job times 2 Learning curve The time required to perform a task decreases with increasing repetitions The degree of improvement is a function of the task being done Short, routine tasks will show modest improvement relatively quickly Longer, more complex tasks will show improvement over a longer interval Learning Curves LO 3 The learning effect is attributed to a variety of factors: Worker learning Preproduction factors Tooling and equipment . | Learning Curves Supplement 7 Copyright © 2015 McGraw-Hill Education. All rights reserved. No reproduction or distribution without the prior written consent of McGraw-Hill Education. 1 Supplement 7: Learning Objectives You should be able to: LO Explain the concept of a learning curve LO Make time estimates based on learning curves LO List and briefly describe some of the main applications of learning curves LO Outline some of the cautions and criticisms of learning curves LO Estimate learning rates from data on job times 2 Learning curve The time required to perform a task decreases with increasing repetitions The degree of improvement is a function of the task being done Short, routine tasks will show modest improvement relatively quickly Longer, more complex tasks will show improvement over a longer interval Learning Curves LO 3 The learning effect is attributed to a variety of factors: Worker learning Preproduction factors Tooling and equipment selection Product design Methods analysis Effort expended prior to the start of work Changes made after production has begun Changes in work methods Changes in tooling and equipment Managerial factors Improvements in planning, scheduling, motivation, and control The Learning Effect LO 4 The learning effect is predictable The learning percentage is constant Every doubling of repetitions results in a constant percentage decrease in the time per repetition Typical decreases range from 10 to 20 percent Interesting Characteristics of Learning LO 5 Each time cumulative output doubles, the time per unit for that amount should be approximately equal to the previous time multiplied by the learning percentage. If the first unit of a process took 100 hours and the learning rate is 90%: Learning Illustrated Unit Unit Time (hours) 1 = 100 2 .90(100) = 90 4 .90(90) = 81 8 .90(81) = 16 .90() = 32 .90() = LO 6 Unit Times: Formula Approach LO 7 If the learning .