Work Design: Productivity and Safety

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IE 419 Work Design Productivity and
Safety Dr. Andris Freivalds Class 11
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IE 419 Work Design Productivity and
Safety Dr. Andris Freivalds Class 11
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Motion Study (pp. 148-153)

• Detailed analysis of motions in operation
• Developed by Gilbreths (bricklaying)
• Goals
• Increase productivity
• By eliminating ineffective motions
• Improving (faster) effective motions
• 17 fundamental motions (therbligs)

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Two-Hand Process (Simo) Chart(Used to Analyze
Motions in Operation)
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Therbligs Two-Hand Process Chart
Conclusions
Basis for Predetermined Time Systems!
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Predetermined Time Systems (Ch. 13, pp. 468-470,
475-484, 504-508)

• PTS technique for obtaining a standard time
  (vs. time study, work sampling) via
• Analyze and subdivide a task into elemental
  motions (therbligs)
• Assign pre-set time values for these elements
• Summate times to obtain a standard time for whole
  task (no direct timing)

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History of PTS

• Based on Gilbreths therbligs
• Time added in for each therblig
• First Work Factor in 1930s
• Now over 200 PTS systems
• Focus on MTM based ones

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Methods Time Measurement (MTM)

• Maynard, Stegemerten, Schwab in 1940s
• Westinghouse jobs, broken down into elements,
  rated, timed
• Time Measurement Unit (TMU) 0.00001 hr 0.0006
  min 0.036 sec
• Main variations tradeoff of speed accuracy
  MTM-1, 2, 3
• Specialized variations for jobs MTM-C for
  clerical, MTM-V for machines, MTM-M for
  magnification

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Comparison of MTM-1,-2,-3
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Accuracy vs. Length of Cycle