My Class

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

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Other 7 Elemental Motions - 2

• Eye Action (E) 7 TMU
• Recognize an object or
• Shift line of sight out of normal area of vision
• Dont overdue, G and P have already
• Crank (C) 15 TMU/rev
• Hand/fingers move in circular path gt ½ rev
• If lt ½ rev, use G and/or P
• May need GW to overcome stiction
• May need PW for sticky crank

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Other 7 Elemental Motions - 3

• Steps (S) 18 TMU/step
• Leg motion to move body,
• Distance gt 12
• Foot Motion (F) 9 TMU
• Short foot motion, to press pedal
• Distance lt 12
• Bend Arise (B) 61 TMU
• Vertical displacement of body
• Bend, stoop, kneel on one knee
• Kneel on both knees 2B

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MTM-2 Application

• Use MTM Methods Analysis Chart
• Summarize motions by hand (L R)
• Add TMUs (no ratings needed)
• Add allowances
• Consider special cases

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Summary of MTM-2 Data
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Insertion vs. Alignment PUT
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Continuous vs. Intermittent Crank
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1) Simultaneous Motion

• Simo difficult motions require more time
• Add a penalty

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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

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Examples
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Sources of Error

• Discreteness tabular data
• No interpolation
• Hopefully, this averages out
• Synthesis assumes correct process
• Need correct application - practice

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Ex U-bolt assembly
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Job Analysis - Surveys 1 Body discomfort maps
(Corlett,1976) Category ratio (CR-10) scale
(Borg, 1982)
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Job Analysis - Surveys 2Nordic Questionnaire
(Kuorinka, 1987)
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Job Analysis - Surveys 2Nordic Questionnaire
cont
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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 (lt10, lt20, gt20 kg)

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OWASCode 2151 2 bent back1 both arms
below shoulders5 kneeling 1 lt10 kg load
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OWAS Acceptable Limits
Measure time in each posture
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Gross Posture Categorization 4 (Keyserling, 1986)
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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)