Industrial Engineering
Faculty - Er. Ruchita Joshi
Index
Unit 1
Productivity
Work Study
Unit 2
Plant layout and materials Handling
Replacement Analysis
Maintenance Management
Unit 3
Inventory Control
Quality Control
Unit 4
Industrial Ownership
Manpower Planning
Organization
Job Evaluation & Merit rating
Unit - 1
Chapter - 1
Productivity
Productivity
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Productivity is a measure of how well resources are utilized to produce output.
Productivity is a measure of output from a production process, per unit of input.
In other words Productivity may be defined as the ratio of output/input.
In engineering the ratio of output/input is termed as efficiency however in
production system this ratio is known as production efficiency or productivity.
• Productivity can also be defined as human efforts to produce more and more with
less and less inputs of resources.
• According to Peter Drucker, “Productivity means a balance between all factors of
production that will give the maximum output with the smallest effort”.
• European productivity council defines, “Productivity is an attitude of mind. It is a
mentality of progress, of the constant improvement of that which exists. It is
certainty of being able to do better than yesterday and continuously.”
Examples of Productivity
• A tailor is able to make 10 shirts from 13 meters cloth, by changing his cutting
method in place of the usual 1.5 meters per shirt he used to take previously.
• A farmer produces 10 more bags of wheat in a season, in the same area of land,
using improved farming technique and better quality seeds.
• A lathe machine tool, instead of 80 jobs being produced previously, now produces
100 jobs per day using improved material of cutting tool.
• A machinist is able to produce 30 jobs per shift by attending two machines at a
time, instead of 20 jobs per shift by attending only one machine at a time.
• The common thing in all above is the increase of output without any change in
input. Farmer produced more without change in input only by changing farming
technique & using better quality seeds. Tailor is able to increase number of shirts
by using only improved method of cutting, in which input (cloth) per shirt reduces
and the output remains constant.
Production and Productivity
• Production refers to absolute output while the productivity is a relative term
wherein output is always expressed in terms of input.
• Production is related to the activity of producing goods or service. It is a process (or
system) of converting input into some useful, value added output.
• The production may rise with without the corresponding rise in the productivity
and vice versa.
• If the input remains the same and the production of output increases there is a rise
in productivity.
• If the input and output are both varying & output rises in greater proportion than
increase in input, there is a still rise in the level of productivity & if the output rises
at a slower rate than the input there will be a fall in productivity even though there
is an increase in production as a whole.
• Production therefore means the output in terms of money whereas the
productivity is the efficiency of production system.
Measurement of Productivity
The basic objectives behind productivity measurement is
• To study performance of a system over a period of time.
• To have relative comparison of different systems for a given level
• To compare the actual productivity of the system with its planned productivity.
Productivity is measured in following three manners:
• Partial Productivity
• Total Factor Productivity
• Total Productivity
Partial Productivity
Partial Productivity
• It may be defined on the basis of class of input being considered.
• Example includes, if the labor is increased by 18% during last financial year, its effect on the
increased output is represented by productivity.
• It is a good diagnostic measure to identify areas where improvements may be done.
Different forms of Partial Productivity
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Partial Productivity
Formula
Uses
1.
Labor Productivity or Human
Productivity
Total Revenue from production /
Expenditure on labor
To understand the effect of increase/decrease in the
hiring of labor and to see how they perform.
2.
Material Productivity
No. of units produced / Cost of
material
In material management
3.
Capital Productivity
Turnover / Capital employed
In financial assessment
4.
Energy Productivity
Output / Energy Input
In the consideration of energy required by the system
5.
Advertising and Media
Planning Productivity
Output / Advertising and Media
Planning Input
In marketing management
6.
Other Expense Productivity
Output / Other Expense Input
In the analysis of system
Total Factor Productivity
Total Factor Productivity
• It is the ratio of the net output to the sum of labor and capital inputs.
• This method is preferred as it is easy to compare in cross-industry context.
• It involves a disadvantage as many important inputs, such as material, energy, etc. are ignored.
Formula for Total Factor Productivity
Total factor productivity =
Net Output
-----------------------------Labor + Capital Inputs
= Total Output – Intermediate goods / Services purchased
-------------------------------------------------------------------------------Labor + Capital Input
Total Productivity
Total Productivity
• It is the ratio of the total output to the sum of all inputs factors.
• Since it contains all the input and output factors thus it is a more accurate representation of
real economic performance of the organization.
• It is easy for top management to understand the company performance.
• Its study with partial productivity, reveals the focused areas of improvements.
• Since it includes total factors summation hence it is difficult to generate companywide and
sector wise data.
• While calculating total productivity many indirect measures of input/output are ignored.
Productivity Index
• It shows the total kinds of productivity measurements.
Productivity Index
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Partial Productivity
Formula
Uses
1.
Labor Productivity or Human
Productivity
Total Revenue from
production / Expenditure on
labor
To understand the effect of increase/decrease in the hiring
of labor and to see how they perform.
2.
Material Productivity
No. of units produced / Cost
of material
In material management
3.
Capital Productivity
Turnover / Capital employed
In financial assessment
4.
Energy Productivity
Output / Energy Input
In the consideration of energy required by the system
5.
Machine Productivity
Output / Actual Machine
hours utilized
Machine hours management
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Raw material productivity
Total output / Cost incurred
in raw material
Effective use of raw material
Ways to improve Productivity
• It can be improved either by proper use of resources or by effective utilization of system or
processes.
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Area of focus
Agenda
1.
Machine
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Manual labor be replaced by machines
Reliable machines
Automation
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Management
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Motivated workforce
Better planning and co-ordinations
Effective control of processes
3.
Process
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Computerization of system
Use of Management Information System (MIS)
Improvement in scheduling
Better material flow
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Work Design
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Improved job design
Better work method
On-job training
5.
Work Environment
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Better lighting and illumination
Better ventilation
Safe work place
Total Quality Management (TQM)
Ways to improve Productivity contd…
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Area of focus
Agenda
6.
Program
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Quality circle
Suggestion schemes
Incentive schemes
Revise pay or policy
7.
Technology
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Acquire new technology such as Electro chemical machining (ECM) etc.
Acquire computer controlled machines such as CNC
Use automated guided vehicle (AGV) for material transportation
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Manufacturing Strategy
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Change the manufacturing system from functional to cellular layout if it is a batch
production unit
Adopt stockless production strategy and Just-in-time (JIT) framework in production unit
Keep work place clean and environment friendly
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Better political stability
Boosting economy and purchasing capacity of buyers
Globalization and open market economy
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External Environment
Production system
• In order to convert the basic inputs like men, material, money, energy, information
etc, into useful outputs like finished products and services a transformation process
is needed.
• This transformation is done through a process known as production.
Thus a production system can be defined as a transformation system in which a
saleable product or service is created by working upon a set of inputs given above.
• Production systems are usually classified on the basis of the following:
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Type of product,
Type of production line,
Rate of production,
Equipments used etc.
Types of Production system
• The production system varies from factory to factory and from product to product.
However one of the most important issues is production volume.
Types of Production systems
Types of
Production
systems
Intermittent
Production
Project
Production
Job shop
Production
Continuous
Production
Batch
Production
Mass & Flow
Production
Process or
Continuous
Production
Intermittent Production system
In this system, the goods are manufactured specially to fulfill orders made by
customers rather than for stock.
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Here the flow of material is intermittent.
Intermittent production systems are those where the production facilities are
flexible enough to handle a wide variety of products and sizes.
These can be used to manufacture those products where the basic nature of
inputs changes with the change in the design of the product and the production
process requires continuous adjustments. Considerable storage between operation
is required, so that individual operations can be carried out independently for
further utilization of men and machines.
Examples of intermittent system are: machine shops, hospitals, general office etc.
Types of Intermittent Production system
Project Production
Project production where a single assignment of complex nature is undertaken for
completion within the given period and within the estimated expenditure.
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Generally work is carried out at the site of the work rather than in a factory. All
resources such as tool, material, labor etc. reach the site itself.
Many civil engineering projects for construction or military related activities are
project production.
The ship building is the example of project production
Types of Intermittent Production system
Job Shop Production
In this system products are made to satisfy a specific order. However that order may be produced:
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only once
or at irregular time intervals as and when new order arrives
or at regular time intervals to satisfy a continuous demand
Job shop production is characterized by its low production volume.
The production lot size is generally small.
Machines and methods employed should be general purpose as product changes are quite frequent.
Planning and control system should be flexible enough to deal with the frequent changes in product
requirements.
Man power should be skilled enough to deal with changing work conditions.
Schedules are actually non existent in this system as no definite data is available on the product.
In process inventory will usually be high as accurate plans and schedules do not exist.
Product cost is normally high because of high material and labor costs.
Grouping of machines is done on functional basis (i.e. as lathe section, milling section etc.)
This system is very flexible as management has to manufacture varying product types.
Material handling systems are also flexible to meet changing product requirements
Types of Intermittent Production system
Batch Production
Batch methods require that the work for any task is divided into parts or operations. Each
operation is completed through the whole batch before the next operation is performed.
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Batch production is suited for medium volume lot of same variety.
It is commonly used to meet repeated customer orders.
Machines are grouped on functional basis similar to the job shop manufacturing.
Labor should be skilled enough to work upon different product batches.
In process inventory is usually high owing to the type of layout and material handling policies
adopted.
Semi automatic material handling systems are most appropriate in conjunction with the semi
automatic machines.
Normally production planning and control is difficult due to the odd size and non repetitive
nature of order.
Continuous Production system
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In this system the items are produced for the stocks and not for specific orders.
Before planning manufacturing to stock, a sales forecast is made to estimate likely
demand of the product and a master schedule is prepared to adjust the sales
forecast according to past orders and level of inventory.
Here the inputs are standardized and a standard set of processes and sequence of
processes can be adopted. Due to this routing and scheduling for the whole
process can be standardized.
Types of Continuous Production system
Mass Production
In mass production, same type of product is manufactured to meet the continuous demand
of the product. Usually demand of the product is very high and market is going to sustain
same demand for sufficiently long time.
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As same product is manufactured for sufficiently long time, machines can be laid down in
order of processing sequence. Product type layout is most appropriate for mass production
system.
Standard methods and machines are used during part manufacture.
Most of the equipments are semi automatic or automatic in nature.
Material handling is also automatic (such as conveyors).
Semi skilled workers are normally employed as most of the facilities are automatic.
As product flows along a pre defined line, planning and control of the system is much easier.
Cost of production is low owing to the high rate of production.
In process inventories are low as production scheduling is simple and can be implemented
with ease.
Types of Continuous Production system
Process or Continuous Production
Process production is characterized by tile manufacture of a single product produced and
stocked in the warehouses awaiting sales.
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The flexibility of such plants is almost zero as only one type of product can be produced in
such plants.
Special purpose machines with built-in controls are used.
Materials handling is highly mechanized.
Typical examples of such plants are sugar, steel, cement, paper, coke, refineries, etc.
Unit - 1
Chapter - 2
Work Study
Work Study
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Since the beginning of human race there had always been a tendency to improve in many
activities, but it has been recognized at a very later stage.
Work study is one of the most important management techniques which is employed to
improve the activities in the production.
British Standard Glossary (BSG) defines, “Work study is a generic term for those techniques,
particularly method study and work measurement, which are used in the examination of
human work in all its contexts, and which lead systematically to the investigation of all the
factors which affect the efficiency and economy of the situation being reviewed, in order to
effect improvement.”
Work study is simply the study of work. It is the analysis of work into smaller parts followed
by rearrangement of these parts to give the same effectiveness at a better cost.
Work study is used to associate two sets of techniques which are distinct approaches but yet
interdependent.
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2.
Method Study
Work measurement
Work Study in a diagrammatic manner
Work Measurement:
Method Study
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British Standard Glossary (BSG) defines, “Method study is the systematic recording and
critical examination of existing and proposed ways of doing work, as a mean of developing
and applying easier and more effective methods and reducing costs.”
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Method study is concerned with “the way in which work is done (i.e. method)”. It is used to
simplify the way to accomplish a work and to improve the method of production.
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Method Study aims to determine the most effective method of performing a job, the most
logical layout of manufacturing facilities, the smooth flow of men and materials throughout
the organization and the right placement of inspection stages to enable processing of a job
through the smallest possible time and the least possible cost.
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There is a continuous need for analyzing existing method even if they are developed to be
most efficient and effective because best method today may not be the best method after
some period. Subsequent investigations may reveal that more economical material is
available, more efficient machines, tools, jigs, fixtures have been designed, better inspection
methods have been evolved, more satisfactory material handling equipments can now be
procured and so on.
Method Study - Purpose & Benefits
Purpose/Benefits of method study
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To evolve creatively and innovatively improvement in processes and procedures.
To determine the correct sequence of operations and avoid duplication (if any).
To improve layout, smoothen material flow, reduce backtracking and avoid obstacles.
To reduce unoccupied time of the operator and thereby obtain effective use of human
efforts.
To improve utilization of the equipment and thereby reduce manufacturing cycle time per
piece.
To select material of right specifications, cut down process waste, reduce defectives, and
thereby reduce raw material consumption per unit of production.
TO achieve economy in human effort and reduction of unnecessary fatigue.
To develop a better physical working environment.
Method Study - Procedure
Procedure of method study
1. Select - A specific job will be chosen to be examined.
2. Record - The current performance of the job is observed, facts are recorded and
documented. The important features taken into consideration are:
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Activities performed
Operators involved
Equipment and tools used
Materials processed or moved
3. Examine - The job is then examined and its components are challenged on their feasibility
and necessity (purpose, place, sequence, method).
4. Develop - After this alternative methods are developed, documented and the most suitable
will be selected, becoming the base for the new Work Instructions.
5. Install - The new method is installed as standard practice and the operators will be trained on
those new Work Instructions.
6. Maintain - Control procedures to measure the performance, as well as preventing drifting
back to previous methods of work will also be introduced.
Work Study - Benefits
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It helps in optimum use of plant, equipment, manpower and material.
It helps in establishing the standard of performance.
It helps in developing standard work methods.
It helps in establishing the most efficient and effective utilization of human effort.
It helps in synchronizing various resources like men and machine.
It helps in the evaluation of human work.
It helps in efforts towards productivity improvement
It helps in the elimination of wasteful efforts, useless material handling, etc.
It helps in job simplification and work standardization.
It is helpful in developing plant safety schemes, equipment utilization, plant layout and
conductive work environment.
Method Study - Procedure
Selection of the Job
Selection of the jobs to be studied for methods improvement by the method study practitioner is
a managerial responsibility and it (selection) may be based on economic, technical or human
consideration.
1. Economic consideration:- It justifies selection based on economic worth (i.e. money
saving potential of the job.
2. Technical consideration:- It identifies jobs which require studies to overcome
manufacturing difficulties (excessive rejection, relaxation in prefixed performance
standards, inability of the shops to stick to specified machining parameter such as
speeds, feeds, depth of cut etc., inconsistent quality etc.)
3. Human consideration:- It is usually given weightage while introducing method study
practices for the first time.
Method Study - Procedure
Recording of Facts
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Recording by long hand (descriptive method) has its limitations, it is not recommended for
use in method study. Instead, five symbols and eight charting conventions are used to record
facts relating to the job under study.
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Method Study Symbols
1. Operation
3. Transport
2. Inspection
4. Delay
5.
Storage
Method Study - Procedure
Recording of Facts
Method Study Symbols
1. Operation:- An operation occurs when there is a distinct change in physical or chemical
characteristic of an object or, when there is an addition or subtraction or, when there is
consumption of physical effort or, when information is given or received. An operation is
represented by a circle.
2. Inspection:- An inspection occurs when the object is verified against predetermined
standards of quality or quantity, or both. Inspection, unlike operation, does not take the
object one step forward towards completion. It merely verifies whether or not the object has
undergone the required operation as per specifications. Inspection is represented by square.
3. Transport:- An transport occurs when the object is moved from one place to another.
Example- Movement of materials or trolley. Transport is represented by an arrow.
Method Study - Procedure
Recording of Facts
Method Study Symbols
4. Delay:- A delay occurs when the object is held up resulting in delay in the start of next event
i.e. next operation, inspection or transport. Delay is represented by a letter D.
5. Storage:- A storage occurs when the object is kept in an authorized custody and is protected
against unauthorized removal. Storage is represented by an inverted triangle.
Method Study - Procedure
Recording of Facts
Recording Methods
Information Recording Techniques:
Different methods of information recording for the existing method are
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Charts
Diagrams
Templates and Models
Photographic aids (Micromotion study)
Graphic Techniques (cyclegraph and choronocyclegraph)
Method Study - Procedure
Recording of Facts
Recording Methods
Charts
Charts:
Charts are the most popular method of recording data. The activities comprising the job are
recorded by means of symbols and charting conventions. The different type of charts are.
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Operation Process Chart: to give a bird’s eye view of entire process.
Flow Process Chart:
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Man type (or operator process chart): Show detailed sequence of activities performed by the
workman.
Material type (or product process chart): Show detailed sequence of activities performed on the
materials.
Equipment type: Show detailed sequence of activities performed by the equipment.
Multiple Activity Chart: to study man machine utilization, determine number of
machines to be manned by an operator and the like.
Two Handed Process Chart (Operator Chart): to study work bench layout.
Travel Chart: Study the movement of materials, men or equipment.
Process Chart
A Process Chart is a graphic means of representing the activities that occur during a
manufacturing or servicing job.
There are several types of process charts. These can be divided into two groups.
(i) Those which are used to record a process sequence (i.e. series of events in the order in
which they occur) but do not depict the events to time scale. Charts falling in this group are
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Operation process chart
Flow process chart – (man / material / equipment type)
Operator chart (also called Two Handed Process Chart)
(ii) Those which record events in the sequence in which they occur on a time scale so that the
interaction of related events can be more easily studied. Charts falling in this group are
• Multiple activity chart
• Simo chart
Operation Process Chart
Operation Process Chart:
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An operation process chart provides the chronological sequence of all operations and
inspections that occur in a manufacturing or business process.
An operation process chart gives the detailed step by step account of what is done to the
materials from beginning of the first stage to the last (finished product stage).
Only operations and inspections performed on the material are depicted on this chart &
transports, delays and storages are not included.
The operation process chart can be compared to a map of a city where one can have a fair
idea of the layout of the city from its map but one cannot know from it about the lanes and
by-lanes & their inhabitants.
Flow Process Chart
Flow Process Chart:
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A flow process chart sets out the sequence of flow of work of a product, or any part of it
through the section or the department or the factory by recording the events under review.
It is prepared in a manner similar to that of operation chart except that in addition to
symbols for ‘operation’ and ‘inspection’, symbols for ‘transport’, ‘delay’ and storage are also
shown.
Separate flow process charts are prepared for components of the assembly (usually one flow
process chart is prepared for each major component of he assembly) . This implies that the
operation process chart is normally in multiple lines while flow process chart is usually in a
single line.
Flow process charts are of three types: product or material type (also known as product
process chart) which shows the events that occur to material, the operator or man type (also
known as operator process chart) that depicts the activities performed by the man, & the
equipment type which exhibits the activities performed by the equipment.
An important and valuable feature of this chart is its recording of non-productive hidden
costs, such as delays, temporary storages, unnecessary inspections, and unnecessary long
distances traveled. When the time spent on these non productive activities is highlighted,
analyst can take steps to minimize it and thus reduce costs.
Multiple Activity Chart
Multiple Activity Chart:
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A multiple activity chart is chart on which the activities or more than one subject are
recorded to indicate their inter-relationship in a given cycle.
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Worker-Machine process chart and gang process chart fall in the category of multiple activity
charts.
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A worker-machine chart is used for recording and analyzing the working relationship
between operator and machine on which he works. It is drawn to time scale. Analysis of the
chart can help in better utilization of both worker and machine time. The possibility of one
worker attending more than one machine is also sought from the use of this chart.
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A gang process chart is similar to worker-machine chart, and is used when several workers
operate one machine. The chart helps in exploring the possibility of reducing both the
operator time and idle machine time.
Two Handed Process Chart
Two Handed Process Chart :
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It is also called Left Hand – Right Hand chart or Operator Process Chart and shows the
activities of hands of the operator while performing a task.
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It uses four elements of hand work: Operation, Delay (Wait), Move and Hold.
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Its main advantage lies in highlighting un-productive elements such as unnecessary delay and
hold so that analyst can take measures to eliminate or shorten them.
Simo Chart
Simo Chart:
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A Simo chart is another Left-Hand Right-Hand chart with the difference that it is drawn to
time scale and in terms of basic motions called therbligs. It is used when the work cycle is
highly repetitive and of very short duration.
Diagrams
Diagrams:
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Every business activity requires movement of men and materials form one location to
another. Every movement is not essential & some of them may be avoided by rearrangement
of the facilities within the department or by changing the sequence of activities.
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Operation process chart indicate the sequence of events but do not show movements while
flow process charts do record movements but they do not provide a visual picture. The
problems concerning movements can be better visualized by drawing a diagram which may
be either a flow diagram or string diagram.
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A diagram gives pictorial view of the layout of workplace or floor on which locations of
different equipment, machines, etc. are indicated. The movement of subject (man or
material) is then indicated on the diagram by a line or a string. The diagrams are valuable in
highlighting the movement so that analyst can take steps to simplify or reduce it and thus
effect saving in time or reduction in collisions / accidents.
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Two types of diagrams are common: Flow diagram and string diagram.
Flow Diagrams
Flow diagram:
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Flow diagrams are the scale plans on which the movements of an object are traced by lines.
It shows the relative position of the machine tools, work benches, storage racks, inspection
benches etc. on a scaled diagram on which are marked the paths followed by the workmen
and materials.
String Diagrams
String diagrams:
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String diagrams are the scale plans on which the movements of an object are traced by
means of a string. Its advantage over flow diagram is that repetitive movements between
work stations which are difficult to be traced on a flow diagrams can be conveniently shown
on string diagram.
Templates and 3-D models
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Two-dimensional cut outs made from thin card sheet representing machinery, furniture, etc.
can be used for developing new layouts and methods. The templates may have pieces of
permanent magnet attached to them, so that when used on iron board; they remain glued
on the board whenever placed.
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A scaled 3-D model of a working area helps easy understanding of lighting, ventilation,
maintenance and safety aspects that may be important in a method. Such models are often
of great value in demonstrating the advantages of the proposed changes to all concerned.
However, their use is limited because of higher cost involved. Some computer softwares are
available which help in constructing the layout and possibility of visualizing the working of
process in a systematic way.
Work Measurement
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British Standard Glossary (BSG) defines, “Work measurement is the application of techniques
designed to establish the time for a qualified worker to carry out a specific job at a defined
level of performance.”
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Work Measurement is a term which covers several different ways of finding out how long a
job or part of a job should take to complete.
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WM is the means of measuring the time taken in the performance of an operation or series
of operations in such a way that the ineffective time is shown up and can be separated out.
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WM is also used to set standard times to carry out the work, so that any ineffective time is
not included later.
Work Measurement - Purpose & Benefits
Purpose of Work Measurement
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To reveal the nature and extent of ineffective time, from whatever cause so that action can
be taken to eliminate it.
To set standard time for various operations.
For determining idle or rest time of operator.
Rate operator performance.
Gain information to calculate overall production capabilities and Data for capacity planning.
Benefits of method study
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Knowledge about Standard Times is gained
Ability to estimate total work content
Operators can be appraised on factual grounds
Work Measurement - Techniques
Techniques of Work Measurement
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Time study - The study with the stop watch.
Work sampling - It helps to figure out the amount of time occupied by different
activities associated with men or machines.
Analytical Estimating
Synthesis from standard data - It is the compilation of known elements which have
been observed by the stop watch studies.
Predetermined Motion Time Systems (P.M.T.S.) - The time required to do a job is
synthesized by combining the predetermined times for different elements of the
job.
The first two techniques involve direct observations whereas the rest are data based
and analytical in nature.
Work Measurement - Procedure
Procedure of Work Measurement
1. Select: The work to be studied and determine the objectives of the study.
2. Record: All the relevant data relating to circumstances in which the work is being done.
3. Examine: The recorded data and the detailed breakdown to ensure the most effective
methods and motions are being used and unproductive elements are separated from
productive elements.
4. Measure: The time required to complete each element using appropriate work
measurement techniques and calculate the time required to com pile the work cycle which is
known as basic time.
5. Compile: The standard time for the operation or work cycle.
6. Define: Precisely the series of activities and method of operation for which the time has
been compiled and issue the time standards for the activities and methods specified.
Time & Motion Study
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A time and motion study is used to reduce the number of motions in performing a task in
order to increase productivity & to make sure that the job being evaluated does not include
any unnecessary motion by the worker.
Manufacturing engineering students are being prepared to design work stations, develop
efficient and effective work methods, establish time standards, estimate labor costs, develop
effective tooling, and layout manufacturing facilities. However, the most important thing is
to learn how to train production workers in these skills and techniques so they can become
motion and time conscious.
Motion study is for cost reduction, and time study is for cost control. Motion study is the
creative activity of motion and time study.
Motion study is design, while time study is measurement.
Frederick W. Taylor and his followers developed and refined the Time Study & Frank B.
Gilbreth and his wife Lillian developed and refined the Motion Study.
Earlier the two studies are discussed individually, today they generally are discussed as one.
The objective of the Time and Motion Study is to determine a ‘normal’ or average time for a
job, by using observers to record exactly how much time is being devoted to each task.
Time Study
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International Labor Organization (ILO) defines, “Time study is a work measurement
technique for recording the time and rate of working for the elements of a specified job,
carried out under specified condition & for analyzing the data so as to obtain the time
necessary for carrying out the job at a defined level of performance.”
A method created to determine the ‘correct time’ it takes to complete a certain task
A method to establish ‘the one best way to perform a task’
Time study can reduce cost significantly well.
In organizations that operate without time standards, 60% performance is typical & when
time standards are set, performance improves to an average of 85%. This is a 42% increase in
performance:
85% - 60%
------------------ = 42% performance increase.
60%
Time Study - Equipments
The equipments to be used in Time study are
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Stop Watch
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Fly-back type
Non Fly-back type
Split hand stop watch
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Time Study board
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Time Study forms
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A small calculator
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A reliable clock with seconds hands
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Measuring instruments such as measuring tape, steel rule, micrometer, spring
balance etc.
Time Study - Procedure
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Select the job to be timed
Standardize the method
Select the operator
Record details
Break the task into elements.
Measure the duration of each element and assess the pace of performance
(Performance rating)
Determine representative time for each element
Extend observed time into normal time
Assess relaxation and other allowances
Compute the standard time of job
Motion Study
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Motion studies are performed to eliminate waste. Before any improvement in quality or
quantity of output, any study of operations time, any scheduling of work or balancing of
workload or any calculation of standard time, a study of the current and proposed method is
required.
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Motion study comes first before the setting of time standards. Motion study is a detailed
analysis of the work method in an effort to improve it.
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Studies of overall factory flow or process, called macromotion studies, and then additional
studies of detail or operations, called micromotion studies, should be completed for a
project.
Macromotion Study
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Any process can be studied by dividing it into process activity. Although each activity is
different, depending on the product, there are five classes of activities that are included in all
processes. Savings, may be found in the process by reorganizing activities.
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These activities found in every sequence of processes are
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Operations
Transportations
Inspection
Delay
Storage
Changes in the properties of the product
Changes in the location of the product
Confirmation that change fits to specification
Wait for start of operation, transportation, or inspection
Wait until needed
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When the process is first studied, each activity is recorded and arranged into one of the five
classes. All observed activities are recorded, and activities not done are not recorded. The
purpose of each activity should be studied.
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Example: Pick up the screw driver may have its timed value of several seconds and is studied
under macromotion study.
Macromotion Study Contd…
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Typically, the questions Who? What? Where? When? Why? and How? must be answered.
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Next, each event is observed in the following sequence:
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Can the activity be eliminated? If not,
Can the activity be combined and done with another activity? If not,
Can the activity be rearranged so occur in the sequence at an easier time? If not.
Can the activity be simplified with shorter distances, mechanical assist, or reduced
complexity?
Once these questions are asked and the improvement sequence is defined, it is necessary to
draw a chart or diagram that shows the motion improvements.
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Process Flow Plan
Process Operations Chart
Process Chart
Flow Process Chart
Work Cell Load Chart
Route Sheet
A plan-view plant layout with activities overlaid
The sequence of serial and parallel operations
All serial activities on a preprinted form
All serial and parallel activities on a single page
A plan view with repetitive operations
A planning tool for scheduling operations
Micromotion Study
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Considerable wasted motion and idle time can occur within an operation. This time can’t be
found with macromotion studies because is usually within one process operation. The
improvement is gained from reducing the operation cycle time.
Micromotion Study contd…
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Applicable for operations with very short cycles which are repeated thousands of times.
Goes into greater details to determine where movements and efforts can be saved and to
develop the best possible patterns of movements.
Enables operators to perform the operation repeatedly with minimum effort and fatigue.
The technique used for this typically involves filming the operation and hence is known as
micromotion study.
Examples of operators studied could be cashier in the bank – routine job of taking payment
slips from customer and issuing cash.
Time Standard
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The definition of a time standard is “the time required to produce a product at a work station with the
following three conditions:
(1) a qualified, well-trained operator,
(2) working at a normal pace,
(3) doing a specific task.”
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The importance of time standards can be shown by the three statistics 60%, 85%, and 120% performance.
The time standard is one of the most important pieces of information produced in the manufacturing
department. It is used to develop answers for the following problems:
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Determining the number of machine tools to buy
Determining the number of production people to employ
Determining manufacturing costs and selling prices
Scheduling the machines, operations, and people to do the job and deliver on time
Determining the assembly line balance, determining the conveyor belt speed, loading the work cells
with the correct amount of work, and balancing the work cells
Paying incentive wages for outstanding team or individual performance
Evaluating cost reduction ideas and picking the most economical method based on cost analysis, not
opinion
Evaluating new equipment purchases to justify their expense
Developing operation personnel budgets to measure management performance.
Example of Time Standard
How Many Machines Do We Need?
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One of the first questions rose when setting up a new operation or starting production on a new product
is “how many machines do we need?” The answer depends on two pieces of information:
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How many pieces do we need to manufacture per shift?
How much time does it take to make one part? (Time standard)
EXAMPLE
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The marketing department wants us to make 2,000 wagons per 8-hour shift.
It takes us 0.400 minutes to form the wagon body on a press.
There are 480 minutes per shift (8 hours/shift x 60 minutes/hr).
50 minutes downtime per shift (breaks, clean-up, etc.)
There are 430 minutes per shift available @ 100%.
@ 75% performance (based on history) (0.75 x 430 = 322.5).
There are 322.5 effective minutes left to produce 2,000 units.
322.5
---------------- = 0.161 minutes per unit, or 6.21 parts per minute.
2,000 units
Example of Time Standard Contd…
EXAMPLE
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The 0.161 minutes per unit is plant rate. Every operation in the plant must produce a part every
0.161 minutes; therefore, how many machines do we need for this operation?
Time standard = 0.400 minutes/unit
----------------------------------------------------- = 2.48 machines
Plant rate = 0.161 minutes/unit
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This operation requires 2.48 machines. If other operations are required for this kind of machine,
we would add all the machine requirements together and round up to the next whole number.
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In this example, we would buy three machines. (Never round down on your own. You will be
building a bottleneck in your plant.)
Work Sampling
Work Sampling
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According to BS 3138:1969 “A technique in which statistically competent number of
instantaneous observations are taken, over a period of time, of a group of machines, process
or workers. Each observation records what is seen to happen and the percentage of
observations recorded for a particular activity or delay is a measure of the percentage of
time absorbed by the occurrence.”
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Work sampling is a sampling technique wherein a large number of observations are
conducted at random intervals of time and the state of each member of the group-working
or not working is studied.
The observations of non-working are further amplified and the cause of delay is recorded.
The data so collected can be utilized in a variety of ways.
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Work Sampling - Advantages
Advantages of work sampling
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Cost reduction and cost control.
Assessment of allowances for output standards.
Fixation of output standards.
Testing the accuracy of the output standards.
P.M.T.S.
Predetermined Motion Time System
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According to BS 3138:1969 “Predetermined motion time system (PMTS) is a work
measurement technique whereby times established for basic human motions are used to
build up the time for a job at a defined level of performance.”
Technique of PMTS
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The technique to build PMTS data does not measure element time by a stop watch and thus
it avoids the inaccuracies being introduced owing to the element of human judgment.
It is assumed that all manual tasks in industries are made up of certain basic human
movements (like reach, move, disengage etc.) which are common to almost all jobs.
The average time taken by the normal industrial workers to perform a basic movement is
practically constant.
P.M.T.S. Contd…
Steps involved in collecting PMTS data
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Select large number of workers doing varieties of jobs under normal working conditions in
industries.
Record the job operations on a movie film (micromotion study).
Analyze the film, note down the time taken to complete each element and compile the data
in the form of a table or chart.
The jobs selected are such that they involve most of the common basic motions and are
worked under different set of conditions by workers having different ages and other
characteristics.
Once the table for various basic motions are ready, the normal time for any new job can be
determined by breaking the job into its basic movements, noting time for each motion from
the tables and adding up the time values for all the basic motions involved in the job.
Standard time may be obtained by adding proper allowances.