Method Study: Motion Economy Principles

As an important part of method study, Frank Gilbreth and his wife Lillian Gilbreth, through their various experiments, institutionalized motion and time study through their famous motion economy principles. (You may find it very interesting to refer their biographical 1950 film and book Cheaper by the Dozen).

If one can study the motions and micro motions performed in carrying out an activity and economize on them- try to reduce them, the time taken for the activity can be significantly reduced.

For this, the movements are classified in 5 classes as given below:

• Class 1: Body members moved in this class are fingers and the pivot is knuckle.
• Class 2: Body members moved in this class are hands and fingers and the pivot is wrist.
• Class 3: Body members moved in this class are forearms, hands and fingers and the pivot is elbow.
• Class 4: Body members moved in this class are upper arms, forearms, hands and fingers and the pivot is shoulder.
• Class 5: Body members moved in this class are torso, upper arms, forearms, hands and fingers and the pivot is trunk.

Further, Gilbreth came out with the idea of conducting micro motion study. To facilitate it, a set of fundamental motions required for a worker to perform a manual operation was defined. The set consists of 18 elements, each describing a standardized activity. The set is called "therblig" (read Gilbreth in reverse order and you get this term "therblig" with 'th' treated as one letter). These are listed below:

• Search
• Find
• Select
• Grasp
• Hold
• Position
• Assemble
• Use
• Disassemble
• Inspect
• Transport loaded
• Transport unloaded
• Pre-position for next operation
• Release load
• Unavoidable delay
• Avoidable delay
• Plan
• Rest to overcome fatigue

(Refer our High Quality Management Encyclopedia “Management Universe” at: http://management-universe.blogspot.com/)