December 16, 2011

Motion Study - Human Effort Engineering

Purpose: The goal of motion study is to enhance work performance (quantity and quality of output) through analysis and improvement of body and hand movements. Motion study can be thought of system improvement at a micro level [1] and is a part of human effort engineering.

In the contemporary work environment, motion study also involves reducing the ergonomic stresses associated with a job. This reduces costs (medical treatment and time lost) associated with work injuries. It may also reduce production losses associated with hiring and training replacement workers as well as rehabilitation of persons with work-related injuries.

Principles of motion economy are utilized in motion study. A modified list of principles given by  Mullee and Porter [2] are:

1. Begin each element simultaneously both hands.
2. End each element simultaneously with both hands.
3. Use simultaneous arm motions, in opposite and symmetrical directions.
4. use had motions of lowest classification for satisfactory operations.
5. Keep motion path within normal working area.
6. Avoid share changes of direction. Plan a smoothly curved motion path.
7. Slide small objects. Avoid pickup and carry
8. Locate tools and materials in proper sequence, at fixed work stations.
9. Use fewest elements to obtain shortest time.
10. Use rhythm and automaticity to increase output and lessen fatigue.
11. Relieve both hands with foot pedals where possible.
12. Avoid holding. Use vise or fixture, freeing hands to move pieces.
13. Provide ejectors to remove finished pieces.
14. Use drop deliver where possible.
15. Shorten transports by keeping materials nearby in gravity-feed hoppers.
16. Pre-position tools for quick grasp.
17. Pre-position product for next operation.
18. Locate machine controls nearby for each of operation.
19. Design workplace height of sitting-standing arrangement, and provide proper height chair with comfortable seat and backrest for good posture.
20. Provide pleasant working conditions considering illumination, temperature, humidity, dust, fumes, ventilation, noise level, color scheme, orderliness, and the like.

Right- and Left Hand Chart [2]

In this chart, the activities of the right and left hand are expressed as operations, transportations or moves, holds, and delays and these are represented by the flow-process chart symbols. This chart is also called as a workplace chart or an operator process chart.

The layout of the workplace is indicated by a grid of 1/4 - inch squares, against which the arrangment of bins, fixtures and parts may be shown. The normal working area is indicated by two semicircles described by the operator's forearms when seated at the workplace. The sketch of the part being handled or processed is shown on the chart in the top right hand corner.

The parts and  positions to the left of the operators are shown with the symbols L1, L2 etc. and to the right are shown by the symbols R1,R2 etc.


2. Mullee, William Robert and David B. Porter, "Process Chart Procedure", Chapter 3 in Industrial Engineering Handbook, Ed. H.B.Maynard, 2nd Edition, McGraw Hill, 


Motion study : a method for increasing the efficiency of the workman (1911)
Author: Gilbreth, Frank Bunker, 1868-1924
Subject: Motion study
Publisher: New York : Van Nostrand
Possible copyright status: NOT_IN_COPYRIGHT
The book gives all examples of Bricklaying
Applied motion study; a collection of papers on the efficient method to industrial preparedness (1917)
Fatigue study; the elimination of humanity's greatest unnecessary waste, a first step in motion study (1919)

Films of Frank Gilbreth

Part 1
Part 2
Therblig Analysis
Research Papers

A 36-Hospital Time and Motion Study: How Do Medical-Surgical Nurses Spend Their Time?


Gait and Posture

Journal of Applied Biomechanics

Journal of human movement studies
Journal of motor behavior
MTM journal of methods-time measurement
Motor control: the international journal for the multidisciplinary study of voluntary movement.
Biomechanics: the journal of lower extremity movement


Originally posted at motion-study-human-effort-engineering

Knol Number 1140

Industrial Engineering Knowledge Revision Plan - One Year Plan

January - February - March - April - May - June

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