Ch08-Intro Methods Engrg...Work Systems and the Methods, Measurement, and Management of Work by...

Work Systems and the Methods, Measurement, and Management of Work by Mikell P. Groover, ISBN 0-13-140650-7.

©2007 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.

Methods Engineering

Chapters:

8. Introduction to Methods Engineering and

Operations Analysis

9. Charting Techniques

10.Motion Study and Work Design

Part II



Introduction to Methods Engineering

and Operations Analysis

Sections:

1. Evolution and Scope of Methods Engineering

2. How to Apply Methods Engineering

3. Basic Data Collection and Analysis

Techniques

4. Automation and Methods Engineering

Chapter 8



Methods Engineering

� Analysis and design of work methods

and systems, including the

� tooling,

� equipment,

� technologies,

� workplace layout,

� plant layout, and

� work environment



Other names for methods engineering:

� Work study

� Work simplification

� Methods study

� Process re-engineering

� Business process re-engineering

� Methods Engineering is often

associated with work measurement.



Objectives in Methods Engineering

� Increase productivity and efficiency

� Reduce cycle time

� Reduce product cost

� Reduce labor content

� Improve motivation and morale



Other Objectives

� Improve customer satisfaction

� Improve product and/or service quality

� Reduce lead times and improve work flow

� Increase flexibility of work system

� Improve worker safety

� Apply more ergonomic work methods

� Enhance the environment (both inside and outside the facility)



Operations Analysis

� Study of an operation or group of related operations for the purpose of analyzing their efficiency and effectiveness so that improvements can be developed

� Objectives in operations analysis

� Increase productivity

� Reduce time and cost

� Improve safety and quality

� Same basic objectives as methods engineering

� Methods engineering places more emphasis on design. It is broader than operations analysis.



Evolution and Scope of Methods

Engineering

� Initial research (late 19th century) - Frank Gilbreth: Motion study

� Scientific management (late 19th century-early 20th century)- Frederick W. Taylor: Motion and time study (first principle of the five principles)

� Primary concern: manual physical labor

� Today: methods engineering is applied to areas such as indirect labor, logistics, service operations, office work, and plant layout.



Methods Engineering

Can be divided into two areas:

1. Methods analysis

2. Methods design



Methods Analysis

� Concerned with the study of an existing method or process

� break the method (process) down into work elements or basic operations

� examine the details of the elements: a systematic (= purposefully regular, methodical) search to improve the process

� This involved checklists of questions and suggestions for improvements

� Objectives :

� Eliminate unnecessary and non-value-adding work elements

� Combine elements and operations � Rearrange elements into more logical sequence

� Simplify remaining elements and operations

� In your project



Methods Design

Concerned with either of the following situations:

1.Design of a new method or process

� Required for new product or service and there

is no existing precedent

� Method must be designed from scratch, using

best existing practice for similar operations

2.Redesign of an existing method or process based

on a preceding methods analysis



Systematic Approach in Methods

Engineering

1. Define the problem and objectives

2. Analyze the problem

3. Formulate alternatives

4. Evaluate alternatives and select the best solution

5. Implement the best method

6. Audit the study (follow-ups)

� IE 407-IE 408

� A systematic approach is more likely to yield operational

improvements than an undisciplined approach



Step 1: Define the problem and objectives

� Problem: the reason for needing a systematic approach

to determine its solution

� low productivity, high cost, inefficient methods, the

need for a new method/operation

� Objective: the desired improvement or new methods

design that would result from the project.

� Increase productivity, reduce labor content, improve

safety, develop a new method

� The problem definition and the objectives must be

specific to the problem under investigation.



Step 2: Analyze the problem

� Data collection and analysis.

� Kind of activities involved

� Identify the basic function of the operation

� Gather background information

� Observe existing/similar processes

� Collect data

� Construct experiments on the process

� Develop/utilize a mathematical model of the process

� Perform a computer simulation of the process

� Use charting techniques



Step 3: Formulate Alternatives

� There are multiple ways to perform a task or

accomplish a process.

� Some of them are more efficient and effective

than others

� Formulate all feasible alternatives



Step 4: Evaluate alternatives and select the

best

� Methodical assessment of the alternatives with

respect to the original problem definition and

the objectives.

� Selecting the best one with respect to the

objective (but this is not a simple task)



Step 5: Implement the best method

� Install the selected solution

� Introduce/institute changes proposed in the

existing method

� Pilot studies and trials of the new (revised)

method

� Documentation of the revised method



Step 6: Audit the study

� Continuous improvement (follow-ups)

� Fine-tune the organization’s problem solving

and decision making skills

� How successful was the project in terms of

the original problem definition and the objectives?

� What were the implementation issues?

� What should be done differently in the next study?



The Techniques of Methods Engineering

� The following techniques are mostly accociated with the analysis step in the methods engineering.

� Charting and diagramming techniques

� Motion Study and Work Design

� Facility Layout Planning

� Work Measurement Techniques

� New approaches



Charting & Diagramming Techniques

� They are available mainly for collecting, displaying and analyzing data

� Network diagrams

� Traditional industrial engineering charting techniques � Operation charts

� Process charts

� Flow diagrams

� Other (alternative) diagrams � Block diagrams

� Process maps

� Next week



Motion Study and Work Design

� Concerned with basic motions of a human worker while

performing a given task

� 17 basic motion elements, like reach, grasp, move,

release

� “Principles of motion economy”- guidelines for work

design

� Use of human body in developing the standard

method (e.g., design the work so that both hands are

fully utilized)

� Workplace layout

� Design of tooling used in the task



Motion Study and Work Design -Objective

� Unnecessary motions can be eliminated.

� Some of the motion elements can be

combined.

� The method can be simplified.

� In your project

� 2 weeks later



Facility Layout Planning

� Facility layout refers to:

� Size and shape of a facility

� Arrangement of the different departments and equipment within the facility

� The layout plays an important role in determining the overall efficiency of the operations

� Problem area includes:

� Design of a new facility

� Installing new equipment, retiring old equipment

� Expanding (or contracting) an existing facility

� IE 302 and IE 407



Work Measurement Techniques

� Four basic work measurement techniques:

1. Direct time study

2. Predetermined motion time systems

(PMTS)

3. Standard data systems

4. Work sampling

� They can be used in methods engineering to

make improvements in the work methods

� 3 weeks later



New Approaches

�Lean production

�Based on the Toyota production system

�Embraced by U.S. companies due to its success at Toyota

�Six Sigma and other quality-focused programs

�Widely adopted in industry for improving quality of work processes

�5S: The 5-step work organization:

�Seiri (Sort), Seiton (Set in order), Seiso(Shine), Seiketsu (Standardize), Shitsuke (Sustain)

�Most of the tools used are adaptations of the old IE principles.



Selecting Among Alternative Proposals

� Need for a systematic procedure to decide among alternative proposals

� To begin, list the technical features and functional specifications for the application

� Must features � Some features and specifications that should be guaranteed

at the minimum level.

� Desirable features � Not must features

� Criteria matrix to evaluate alternatives � Proposals are evaluated against the features and

specifications � Eliminate candidates that do not satisfy “must features”

� Develop scores for desirable features



Evaluation of Robots for Welding

Industrial Robot Candidates

Model A Model B Model C Model D

Must features:

Continuous path control OK OK OK OK

Six-axis robot arm OK OK Not OK OK

Walkthrough programming OK OK OK OK

Desirable features:

Ease of programming (0-9) 6 4 6

Capability to edit program (0-5)

4 2 5

Multi-pass features (0-4) 2 2 2

Work volume (0-9) 5 8 6

Repeatability (0-5) 5 2 4

Lowest price (0-5) 4 5 3

Delivery (0-3) 1 1 3

Evaluation of vendor (0-9) 6 5 8

Totals: 33 29 37



Evaluation of Robots for Welding Industrial Robot Candidates

Model A Model B Model C Model D

Must features:

Continuous path control OK OK OK OK

Six-axis robot arm OK OK Not OK OK

Walkthrough programming OK OK OK OK

Desirable features:

Ease of programming (0-9) 6 4 6

Capability to edit program (0-

5)

4 2 5

Multi-pass features (0-4) 2 2 2

Work volume (0-9) 5 8 6

Repeatability (0-5) 5 2 4

Lowest price (0-5) 4 5 3

Delivery (0-3) 1 1 3

Evaluation of vendor (0-9) 6 5 8

Totals: 33 29 37

� Eliminate C because, it doesn’t satisfy one of the must features

� Select D because, it has the highest score among desirable features.



Basic Data Collection & Analysis Tools

1. Histograms

2. Pareto charts

3. Pie charts

4. Check sheets

5. Defect concentration diagrams

6. Scatter diagrams

7. Cause and effect diagrams



Histogram

� A statistical graph consisting of bars representing

different values, in which the length of each bar indicates

the frequency or relative frequency of each member

� A useful tool because the analyst can quickly visualize

the features of the data, such as:

� Shape of the distribution (theoretical form, Normal,

Gama etc.)

� Any central tendency in the distribution (single or

multimodal)

� Approximations of the mean and mode (numerical

value of the centre)

� Amount of scatter in the data (variance or risk)



Number of individual parts



Histogram for Data Display

Normal distribution



Pareto Chart

� Special form of histogram in which attribute data are arranged according to some criterion such as cost or value

� Based on Pareto’s (XIXth century economist who was trying to analyze the distribution of wealth in Italy) Law: “the vital few and the trivial many” also known as 80%-20% rule � 80% of a nation’s wealth is owned by 20% of the

population

� 80% of sales are accounted for by 20% of the SKUs (stock keeping unit or items in stock)



Pareto Distribution



Pareto chart as a cumulative frequency

distribution



Pareto cumulative distribution

�Can be modeled by

where

y=cumulative fraction of the value variable (e.g., wealth, inventory value, revenue),

x=cumulative fraction of the item variable (e.g., population, inventory items, customers)

A is a constant determines the shape of the distribution (shape parameter).

( )10 and 10for

1≤≤≤≤

+

+= xy

xA

xAy



(1 )

x yA

y x

−=

−

To determine A:



Example: Pareto Cumulative Distribution

� Given: 20% of the total inventory items in a

company’s warehouse accounts for 80% of the

value of the inventory.

� Determine:

� (a) The parameter A in the Pareto cumulative distribution equation.

� (b) Given that the relationship is valid for the

remaining inventory, how much of the inventory

value is accounted for by 50% of the items?



Example: Solution

a) x=0.2, y=0.8

A=(0.20(1-0.8))/(0.80-0.20)=0.06667

b) y=(1+0.06667)(0.5)/(0.06667+0.5)=0.941

50% items in inventory account for 94.1% of the value of

the inventory

(1 )

x yA

y x

−=

−

( )10 and 10for

1≤≤≤≤

+

+= xy

xA

xAy



Pareto Chart



Pareto Principle in Turkey

� 80% of the academic publications are affiliated to 20% of

the universities.

� 78% of the earnings are derived from 96 export items,

which makes the 20% of all export items.

� In 2007 elections, three parties (20% of the political

parties) won the 84% of the votes.

� Three highest grossing movies in last November, i.e.,

Harry Potter, New York’ta Beş Minare, Saw 3D (only

20% of the movies) makes 80% of the total gross

revenues.



Pie Charts

Example: Annual sales revenues and customer

distributions for two years



Check Sheet

� Not check lists

� Data collection tool generally used in the preliminary stages of a

study of a quality problem � To recogize the trends

� Diagnose the problem � Identify areas of further study

� Data often entered by worker as check marks in a given category

� Examples: � Process distribution check sheet - data on process variability

� Defective item check sheet – types and frequencies of defects on the product

� Defect location check sheet - where defects occur on the product



� It is clear from the check sheet that the third shift is reponsible for much

of the variability in the data.

� Make an investigation to determine the causes of this variability



� The average daily production rate for the third shift is below the daily rate for the other two shifts.



Defect Concentration Diagram

� A drawing of the product (all relevant views),

onto which the locations and frequencies of

various defect types are added

� Useful for analyzing the causes of product or

part defects

� By analyzing the defect types and

corresponding locations, the underlying causes

of the defects can possibly be identified




•Case study involving final assembly of

refrigerators

•Four views of refrigerator showing locations of

surface defects

Defects

here




•The defects were clearly shown to be concentrated around

the middle section of the refrigerator.

•Upon investigations, it was learned that a belt was wrapped

around each unit for material handling purposes.

•The defects were caused by the belt.

•The necessary correction action was taken.

Defects

here



Scatter Diagrams

� An x-y plot of data collected on two variables, where a

correlation between the variables is suspected

� It is useful to identify a possible relationship that exists

between two processes.

� The data are plotted as pairs; for each xi value, there is a

corresponding yi value

� The shape of the collection of data points often reveals a

pattern or relationship between the two variables



Scatter Diagram

Effect of cobalt content on wear resistance for a

cemented carbide cutting tool

Negative correlation: As cobalt increases wear

resistance decreases.



Cause and Effect Diagram

� A graphical-tabular chart used to list and

analyze the potential causes of a given

problem

� Can be used to identify which causes are most

consequential (related) and how to take

corrective action against them

� Also known as a “fishbone diagram” or “spray

diagram”




� Six general categories of causes 5M + 1P

� Machines

� Equipment, tools etc.

� Materials

� Mother nature

� Enviromental factor such as air temperature,

humadity etc.

� Methods

� Procedures, sequence of activities etc.

� Measurement

� Validity and accuracy of the data collection procedure

� People







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