Motion Study – Human Effort Industrial Engineering


Human effort industrial engineering is a focus area of industrial engineering.
Functions and Focus Areas of Industrial Engineering

Relevant Principles of Industrial Engineering

Human effort engineering for productivity – Principle of Industrial Engineering

In the resources used in engineering systems, human resource is important because all economic activity is to satisfy needs of various categories of persons. Human resources employed in engineering systems have their own needs. Industrial engineers are unique in engineering disciplines in taking up the engineering of human effort. They have to synthesize the theories of human sciences, some of which are developed by industrial engineering also, to design human work for an optimal combination of productivity, income, comfort, health, safety and satisfaction of the employed.

Motion economy – Principle of Industrial Engineering

Operators use motions to do work directly or indirectly through machines. Principles of motion economy were developed by Frank Gilbreth initially. The set of principles is being extended by further research studies.  They need to be employed in all industrial engineering studies in the redesign of human work in engineering systems of all branches.

Operator comfort and health – Principle of Industrial Engineering

As human effort engineers, industrial engineers are also concerned with comfort and health of operators. The productivity improvement should not lead to discomfort, fatigue and musculoskeletal disorders. Each human effort redesign project must be accompanied by an assessment of the comfort, fatigue and health dimensions

Selection of operators – Principle of Industrial Engineering

Different types of engineering trades and work require different types of proficiency from operators. Industrial engineers as well as managers have to identify the proficiency required and select persons for specific operations. Science provides the basis for identifying the proficiencies required for a trade and also the method of evaluating various persons.

Training of operators – Principle of Industrial Engineering

Industrial engineers have to train the operators in the new machine methods proposed by them and in the new man motions. The need to demonstrate the expected output from new methods by specially trained IE department operators is to be emphasized for acceptance of the new methods and resulting higher output.

Motion Study


Motion study is the basic method to study the effort of men in using hands, hand tools and machines and machine tools. Stop watch time study is used to determine the best practice of doing any element of work and such best elemental movements are incorporated in various tasks and operators are trained in the new productive way. Operator comfort, safety, and health are given due consideration in redesigning work in human effort industrial engineering.


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



Motion economy was proposed and developed by Frank Gilbreth through various articles and books and became an important subject of industrial engineering as Time and Motion Study or Motion and Time Study. This subject was modified by European thinkers and practitioners of productivity improvement as Work Study, by proposing methods study as an additional component.




Principles of Motion Economy are to be used in motion design, motion analysis, motion study of human operators. Motion design is a technique of Human Effort Industrial Engineering, a core focus area of Industrial Engineering. They can also be used in robot motion design.
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Use of the Human Body

1. The two hands should begin as well as complete their motions at the same time.
2. The two hands should not be idle at the same time except during rest periods.
3. Motions of the arms should be made in opposite and symmetrical directions and should be made simultaneously.
4. Hand and body motions should be confined to the lowest classification with which it is possible to perform the work satisfactorily.
5. Momentum should be employed to assist the worker wherever possible, and it should be reduced to a minimum if it must be overcome by muscular effort.
6. Smooth continuous motion of the hands are preferable to straight line motions involving sudden and sharp changes in direction.
7. Ballistic movements are faster, easier and more accurate than restricted (fixation) or controlled movements.
8. Work should be arranged to permit an easy and natural rhythm wherever possible.
9. Eye fixations should be as few and as close together as possible.

Arrangement of the workplace

10. There should be a definite and fixed place for all tools and materials. (5S)
11. Tools, materials and controls should be located close to the point of use.
12. Gravity feed bins and containers should be used to deliver material close to the point of use.
13. Drop deliveries should be used wherever possible.
14. Materials and tools should be located to permit the best sequence of motions.
15. Provisions should be made for adequate conditions for seeing. Good illumination is the first requirement for satisfactory visual perception.
16. The height of the work place and the chair should preferably arranged so that alternate sitting and standing at work are easily possible.
17. A chair of the type and height to permit good posture should be provided for every worker.

Design of tools and equipment

18. The hands should be relieved of all work that can be done more advantageously by a jig, a fixture, or a foot-operated device.  (Jig and Fixture Design)
19. Two or more tools should be combined wherever possible. (Combination Tools)
20. Tools and materials should be prepositioned whenever possible.
21. Where each finger performs some specific movement, such as in typewriting, the load should be distributed in accordance with the inherent capacities of the fingers.
22. Levers, hand wheels and other controls should be located in such positions that the operator can manipulate them with the least change in body position and with the greatest speed and ease.
References

Ralph M. Barnes, Motion and Time Study Measurement of Work, 

John Wiley & Sons, New York, 1980


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.


References

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, 

Books

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
Articles
Therblig Analysis
Research Papers

A 36-Hospital Time and Motion Study: How Do Medical-Surgical Nurses Spend Their Time?http://www.rwjf.org/files/research/060908timeandmotion.pdf


Journals

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
http://knol.google.com/k/ motion-study-human-effort-engineering

Knol Number 1140

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Updated on 4 June 2019,  28 May 2019, 2 May 2019