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IE 553 Engineering of Human Work Dr. Andris Freivalds Class #17

IE 553 Engineering of Human Work Dr. Andris Freivalds Class #17. IE 553 Engineering of Human Work Dr. Andris Freivalds Class #17. 7 Other MTM-2 Elements - 1. Apply Pressure (A) = 14 TMU Exert muscular force on object Without moving it (otherwise G or P) Ex: push button

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IE 553 Engineering of Human Work Dr. Andris Freivalds Class #17

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  1. IE 553 Engineering of Human Work Dr. Andris Freivalds Class #17 IE 553

  2. IE 553 Engineering of Human Work Dr. Andris Freivalds Class #17 IE 553

  3. 7 Other MTM-2 Elements - 1 • Apply Pressure (A) = 14 TMU • Exert muscular force on object • Without moving it (otherwise G or P) • Ex: push button • Regrasp (R) = 6 TMU • Change position of object • Without relinquishing control (otherwise G) • Ex: reorient tool IE 553

  4. Other 7 Elemental Motions - 2 • Eye Action (E) = 7 TMU • Recognize an object or • Shift line of sight out of normal area of vision • Don’t overdue, G and P have already • Crank (C) = 15 TMU/rev • Hand/fingers move in circular path > ½ rev • If < ½ rev, use G and/or P • May need GW to overcome stiction • May need PW for sticky crank IE 553

  5. Other 7 Elemental Motions - 3 • Steps (S) = 18 TMU/step • Leg motion to move body, • Distance > 12” • Foot Motion (F) = 9 TMU • Short foot motion, to press pedal • Distance < 12” • Bend & Arise (B) = 61 TMU • Vertical displacement of body • Bend, stoop, kneel on one knee • Kneel on both knees = 2B IE 553

  6. MTM-2 Application • Use MTM Methods Analysis Chart • Summarize motions by hand (L & R) • Add TMUs (no ratings needed) • Add allowances • Consider special cases IE 553

  7. Summary of MTM-2 Data IE 553

  8. Insertion vs. Alignment PUT IE 553

  9. Continuous vs. Intermittent Crank IE 553

  10. 1) Simultaneous Motion • Simo difficult motions require more time • Add a penalty IE 553

  11. Other Special Cases • Principle of limiting motion • For two different motions for each hand • Use the longer time • Principle of combined motion • For two combined motion in one hand • Use longer time • R is included in C-type motions IE 553

  12. Examples IE 553

  13. Sources of Error • Discreteness – tabular data • No interpolation • Hopefully, this averages out • Synthesis assumes correct process • Need correct application - practice IE 553

  14. Ex: U-bolt assembly IE 553

  15. Job Analysis - Surveys #1 Body discomfort maps(Corlett,1976)Category ratio (CR-10) scale(Borg, 1982) IE 553

  16. Job Analysis - Surveys #2Nordic Questionnaire(Kuorinka, 1987) IE 553

  17. Job Analysis - Surveys #2Nordic Questionnaire con’t IE 553

  18. Gross Posture Categorization #3 • Owaco Working Posture Analysis System (OWAS, Karhu, 1977) • Developed at the Finnish Institute of Occupational Health in 1970s • For use in steel industry • Evaluation of posture at regular intervals • Four categories: back, upper limbs, lower limbs, force (<10, <20, >20 kg) IE 553

  19. OWASCode = 2151 2 = bent back1 = both arms below shoulders5 = kneeling 1 = <10 kg load IE 553

  20. OWAS – Acceptable Limits Measure %time in each posture IE 553

  21. Gross Posture Categorization #4 (Keyserling, 1986) IE 553

  22. Comments on Surveys • Should interpret with caution • Workers hesitant to be truthful • Anonymity may be critical • Pain tolerances vary • Proper design, validation critical • Fairly subjective (objective!) • Relatively non-quantitative • More covered in IE 552 (upper extremities) IE 553

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