Lecture Fundamentals of operations management (4/e): Chapter 14 - Davis, Aquilano, Chase

Chapter 10 Work performance measurement, after studying this chapter you will be able to: Introduce the more common types of work methods that are practiced in the workplace, understand the fundamental issues involved in developing work measurements, identify the basic elements associated with conducting a time study,...

Work Performance Measurement

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supplement 10

DAVIS AQUILANO CHASE

PowerPoint Presentation by Charlie Cook

Management 4e 

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• Understand the fundamental issues involved in

developing work measurements

• Identify the basic elements associated with conducting

a time study

• Determine how to design a work sampling study and apply it to an actual operation

Management 4e 

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S10–3

Work Methods

Work Methods

• Studying the production system to:

–Identify non-valued-added time delays, transport

distances, process and processing time

requirements

–Simplify the entire operation by eliminating any

step that does not add value to the product.

Management 4e 

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S10–4

Work Methods and Design Aids

Work Methods and Design Aids

Exhibit S10.1

Management 4e 

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Source: Ralph M Barnes, Motion and Time Study, 8th ed

(New York: John Wiley & Sons, 1980), pp 76–79

Reprinted by permission of John Wiley & Sons, Inc.

*Requisition is written by supervisor, typed by secretary, approved by superintendent, and approved by purchasing agent; then order is prepared by a stenographer.

Management 4e 

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Source: Ralph M Barnes,

Motion and Time Study, 8th

ed (New York: John Wiley &

Management 4e 

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S10–7

Common Notation in Process Charting

Common Notation in Process Charting

Exhibit S10.3

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S10–8

Gilbreth’s Principles of Motion Economy

Gilbreth’s Principles of Motion Economy

Exhibit S10.4a

Source: Frank C Barnes, “Principles of Motion Economy: Revisited, Reviewed, and Restored,”

Proceedings of the Southern Management Association Annual Meeting, Atlanta, GA, 1983, p 298.

Management 4e 

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S10–9

Gilbreth’s Principles of Motion Economy (cont’d)

Gilbreth’s Principles of Motion Economy (cont’d)

Exhibit S10.4b

Source: Frank C Barnes, “Principles of Motion Economy: Revisited, Reviewed, and Restored,”

Proceedings of the Southern Management Association Annual Meeting, Atlanta, GA, 1983, p 298.

Management 4e 

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Management 4e 

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S10–11

Worker­Machine Chart for a  Gourmet Coffee House (cont’d)

Worker­Machine Chart for a  Gourmet Coffee House (cont’d)

Exhibit S10.5b

The customer, the clerk, and the coffee grinder (machine) are involved

in this operation It required 1 minute and 10 seconds for the customer

to purchase a pound of coffee in this particular store

During this time the customer spent 22 seconds, or 31% of the time

giving the clerk his order He was idle during the remaining 69% of the time The clerk worked 49 seconds, or 30% of the time The machine was in operation 21 seconds, or 30% of the time.

Management 4e 

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Source: Data taken from

Harold E Smalley and

John Freeman, Hospital

Industrial Engineering

(New York: Reinhold,

1966), p 490.

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–Elemental standard time data

–Predetermined motion-time data

–Work sampling

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Management 4e 

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S10–15

Time Study

Time Study

• Time Study

–The determination, with the use of a stopwatch,

of how long it takes to complete a task or set of tasks.

–Normal time = Observed performance time per

unit x Performance rating

–Piece rate is the rate paid for work completed –Break down tasks by:

• Defining each work element.

• Separating human work from machine work.

• Defining operator and machine delays separately.

Management 4e 

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S10–16

Elemental Standard­Time Data

Elemental Standard­Time Data

• Time Standard

–The established time for completing a job, used

in determining labor costs associated with

making a product.

–Steps

• Breakdown the new job into its elements

• Match elements to the time for similar job-specific

elements in the elemental table.

• Adjust elements for special characteristics of the

new job.

• Add element times together and add delay and

fatigue allowances.

Management 4e 

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S10–17

Predetermined Motion­Time Data

Predetermined Motion­Time Data

• Predetermined Motion-Time Tables

–Create a time standard for a job or task based

on standard times for basic motions (therbligs).

–Can be applied to a wide-variety of tasks.

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S10–18

Work Sampling

Work Sampling

• Work Sampling

–A statistical technique for estimating how

workers allocate their time among various

activities throughout a workday.

–Issues involved:

• What level of statistical confidence is desired in

the results?

• How many observations are necessary?

• When should the observations be made?

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Z N

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S10–20

Work Sampling (cont’d)

Work Sampling (cont’d)

• Steps in Conducting a Work Sampling Study:

–Identify the activities for study.

–Estimate the proportion of time of the activity of

interest to the total time.

–State the desired accuracy in the study results –Determine the specific time when each

observation is to be made.

–If using an estimated time, recompute the

required samples size at intervals during the

study and adjust the number of observations.

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S10–21

Assignment of Numbers to  Corresponding Minutes

Assignment of Numbers to  Corresponding Minutes

Exhibit S10.8

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S10–22

Determination of Observation Times

Determination of Observation Times

Exhibit S10.9

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S10–23

Observation Schedule

Observation Schedule

Exhibit S10.10

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