Work Design: Productivity and Safety

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IE 419 Work Design Productivity and
Safety Dr. Andris Freivalds Class 12
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IE 419 Work Design Productivity and
Safety Dr. Andris Freivalds Class 12
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Use MTM-2 When

• Cycle time gt 1,600 TMUs ( 1 min ? 5)
• Cycle is not highly repetitive
• No complex finger motions used
• Ex dealing a deck of 52 cards
• Time
• Repetitive
• Finger motions

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9 Elemental Motions

• GET (G) gain control of object
• Reach for an object
• Grasp object
• (eventually) Release object
• PUT (P) move object (when under control) to new
  location
• Move object to new location
• Position object to proper location

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Variations of GET PUT

• Case type of grasping or correcting motion,
  amount of control needed
• Distance reached
• Weight of object or resistance
• Type of PUT
• Insertion difficulty (one object into another)
• Surface alignment

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Cases for GET(G)
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Cases for PUT (P)
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Clearances (in.) for Insertion vs. Alignment PUT
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Distance Code
gt32 ? step
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Weight Factor

• If significant weight moved, additional time is
  needed
• GET Weight (GW) 1 TMU for each 2 lbs up to 40
  lbs
• Values are per hand (20 lb box ? 5 TMU)
• PUT Weight (PW) 1 TMU for each 10 lbs (above
  4 lbs) up to 40 lbs
• Resistance Ffriction 0.4 N

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Other Elemental Motions - 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
• Squat, 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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Comparison of MTM and Time Study
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Ex U-bolt (Cable clamp) assembly