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IE 419 Work Design: Productivity and Safety Dr. Andris Freivalds Class #11. 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
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IE 419 Work Design:Productivity and Safety Dr. Andris Freivalds Class #11 IE 419
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) IE 419
Two-Hand Process (Simo) Chart(Used toAnalyze Motions in Operation) IE 419
Therbligs & Two-Hand Process Chart Conclusions: Basis for Predetermined Time Systems! IE 419
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) IE 419
History of PTS • Based on Gilbreths’ therbligs • Time added in for each therblig • First – Work Factor in 1930’s • Now over 200 PTS systems • Focus on MTM based ones IE 419
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 IE 419
Comparison of MTM-1,-2,-3 IE 419
Accuracy vs. Length of Cycle IE 419