Thursday, April 19, 2012

Work Measurement - Nadler's Description

Gerald Nadler described the process of work measurement under the following chapters.

20. Concepts and Problems of Standards Setting
21. Recording Conditions and Method
22. Timing
23. Pace Comparison
24. Difficulty comparison
25. Allowances
26. Standard Data
27. Applying and Controlling Standards

Industrial Need for Standards

1. Balance of work
2. Equipment Requirements
3. Manpower Requirements
4. Production Planning
5. Cost Planning
6. Production Control
7. Cost Control
8. Wage Incentives

What is Standards Setting?

Standards setting techniques determine the time an operation or element of an operation, performed with a given method under given job conditions, should take; when worked on by an operator with the necessary skill and given sufficient training to perform the operation properly, working at the pace, maintainable througout the day, week etc., specified as equivalent to the work necessary to earn base pay; and when all the operator's required activity and needs are provided for. This amount of time is called the allowed or standard time.

Methods of Standard Setting

1. Time Study: Study of operation while it is being performed.
2. Standard Data: Determining standard for an operation by reference to information from earlier studies on similar jobs jobs having similar elements, collected and arranged properly.

Factors in Time Study

1. Given Method
2. Job Conditions
3. Time for Operation or Element

In a time study operation time is to be measured and along with it the pace of the operator and difficulty of of the operation are also to be measured.

Nadler comes out with a concept called Factor X which if it improves reduces the time required to do an element. Al the items influencing Factor X can be summed up as the operator's psychological, physiological, and sociological relation to his environment and operation.

Recording Conditions and Method

Allowed time or standard time is associated with a given method.

The steps involved in recording conditions and method are:

1. Get permission of the foreman and cooperation of the operator
2. Observe the method
3. Record all conditions surrounding the operation
4. Make a rough breakdown of the operation - Regular occurrences and irregular occrrences
5. Break the work into elements
 a. Elements have therbligs as much alike as possible
 b. Have a definite end point
 c. Are  as short as possible, compatible with accuracy of the measuring instrument
      With a stop watch 0.03 to 0.04 minute can be measured.
      With motion films times up to 1/16 second  can be measured. But practically less than 0.01 minute are not used.
 d. Separate machine time and manual time
  e. Separate constant elements and variable elements
6. Detail each element
7. Put all information in final form


Timing techniques or Instruments

1. Electronic Devices
2. Motion pictures
3. Paper-tape recording machines
4. Stop watches
5. Sweep second wrist watch
6. Occurrence study (Work sampling)
7. Wall clock
8. Operator records time

The Timing Procedure

1. Check training record of the operators and select the operator
2. Check the method: To make sure operator is using the same method that is recorded in the recording step of the time study.
3. The analyst must have proper position to observe the end point of every element.
4. How many readings?
A graphical aid was given by Lehrer and Moder in Journal of Industrial Engineering, February 1953.
Mathematical treatment is also given by Nadler (pp. 370-378)
5. Timing machine controlled elements: Even though they can be calculated timing them is advised.
6. Record all occurrences, irregular elements, unexpected events etc.
7. Measure of central tendency for the element

Pace Comparison

After discussing measuring time, Nadler discusses measurement of Factor X. He said any of them can be discussed first. Time study is supposed to determine the amount of time an operation should take for any average operator. Hence, observation of any operator for determining the allowed time must be related in some way to a concept which will provide standard time. Factor X is conceptualized to have effect on observed time.

Two factors are to be evaluated in doing time study.

1. How is the operator's performance in comparison to performance other members of his group, or plant or operators in general?
2. How does the job being studied compare in terms of difficulty with other operations in the plant?

The answers to these two questions help adjusting the observed values to get standard value.

Does Factor X decrease with time? Nadler answers this question with no. Factor X does not decrease with time, but late in the day, operators take more timeouts is the answer of Nadler.

Factor X needs to be measured for each element. But it may not be possible unless element has a time measurement of 0.5 minute or higher.

Review of Factor X measuring techniques: Nadler presented a review of Factor X measuring techniques.
1. Over-all Evaluation
2. Good Performance
3. Mathematical or Statistical Manipulation of Time Data
4. Skill and Effort
5. Speed
6. Speed with 100 Per Cent Film
7. Speed Measurements with 100 Per Cent Step Film, Separated from Job Difficulty Measurements
8 Acceleration,Velocity, and Deceleration of Body Motions Measurements,with Universal Operator Performance Analyzer and Recorder (UNOPAR),Separated from Job Difficulty Measurements.

Nadler also discussed the issue of validating the pace measurements or Factor X measurements.

Source: Gerald Nadler, Motion and Time Study, McGraw-Hill Book Company, Inc, New York, 1955
Original Knol - 2668

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