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Objectives of Charts and Diagrams
Used in Methods Engineering
Charting and Diagramming
Techniques for Operations Analysis
Chapter 9
Sections:
1. Overview of Charting and Diagramming Techniques
1. To permit work processes to be communicated and
comprehended more readily
2. To use algorithms specifically designed for the particular
diagramming technique
2. Network Diagrams
3. Traditional Engineering Charting and Diagramming
Techniques
4. Block Diagrams and Process Maps
Gantt Charts ?
3. To divide a given work process into its elements for
analysis purposes
4. To provide a structure in the search for improvements
5. To represent a proposed new work process or method
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.
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.
How to Create / Develop the Chart or
Diagram?
How to Analyze the Chart or Diagram
Analyst is intimately familiar with the process and
develops a graphic to represent it
Algorithmic analysis
Analyst observes and records information about the
process
Checklists
One-on-one interviews with those familiar with the
process
A graphic model of the process is developed based on
these interviews
Group meetings with personnel familiar with process
The analyst records the discussion of the meeting.
A graphic model of the process is developed based on the
group meetings
Line balancing, critical path methods
General questions applied to the particular process to
assess whether they can be applied to the problem of
interest
Brainstorming
Team
activity
in
recommendations
What alternative starting material could be
used?
Should the part be produced or purchased?
Can this operation be eliminated, combined, or
simplified?
participants
Value added steps:
1.
2.
Important to customer
Physically change the product or service
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.
Categories of Charts and Diagrams
1. Network diagrams
2. Traditional industrial engineering charts and
diagrams
Operation charts
Process charts
Flow diagrams
Activity charts
Could a different joining method be used?
3. Block diagrams and process maps
Could the inspection task be automated?
4. Gantt charts
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.
contribute
Separating value-added and non-value-added operations
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.
Checklist of Questions - Example
which
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.
1
Network Diagrams
Consist of:
Nodes representing operations, work elements, activities or other
entities
Arrows connecting the nodes indicates relationships among the
nodes
Direction of work flow between nodes
Precedence among nodes
Used to represent
Work elements in assembly line balancing
Work activities in CPM and PERT
Two-way flows (movement of materials):
One-way arrows (precedence):
Network Diagram - Precedence Constraints
Restrictions on the order in which work
elements can be performed
Precedence
diagram
Maximum number of arrows = n(n -1)
Maximum number of arrows =
n(n − 1)
2
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.
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.
Traditional IE Charts and Diagrams
Operation charts
Process charts
Operation Charts
Graphical and symbolic representation of the operations used
to produce a product
The time to accomplish the operation is sometimes also
included.
Two types of operations:
Flow diagrams
Activity charts
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.
1.
Processing and assembly operations
Changing the shape, properties or surface of a
material or workpart
Joining two or more parts to form an assembly
2.
Inspection operations
Checking the material, workpart, or assembly for
quality or quantity
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.
Operation Chart
Component
Subassembly
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.
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.
2
Checklist of Questions Used to Analyze an
Operation Chart
The focus of the operation chart is on the materials of a product
and the operations on them
Questions related to material
What alternative starting material could be used?
Make or buy decision: should the part be produced in the
factory or purchased?
Questions related to operations
Is this processing operation necessary?
Can this operation be eliminated, combined, or simplified?
Could a different joining method be used?
Questions related to inspection
Is this inspection necessary?
Could the inspection task be automated?
Operation Charts
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.
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.
Process Charts
Flow Process Chart
Graphical and symbolic representation of the processing
activities performed either on something or by somebody.
The chart consists of a vertical list of activities using symbols
to represent operations, inspections, moves, delays and
storage and other activities.
Principal types of process charts:
1.
2.
3.
Flow process chart – analysis of a material or workpiece being
processed
Worker process chart – analysis of a worker performing a task
Form process chart – analysis of the processing of paperwork
forms
All these charts are used
improvements of operations
to
examine for
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.
possible
Uses five symbols to detail the work performed
on a material or workpart as it is processed
through a sequence of operations and activities:
Operation – processing of a material
Inspection – check for quality or quantity
Move – transport of material to new location
Delay – material waiting to be processed or
moved
Storage – material kept in protected location
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.
Flow Process Charts
If the processing operation combined with an inspection
at the same workstation: combine symbols - a circle
inside a square
Provides more detail about the steps required to process
a material than in the operation chart:
is used to study a single work part rather than the
multiple components of an assembly
The chart also indicates distances for move activities
and time values for other activities
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.
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.
3
Form for Flow Process Chart
Checklist of Questions Used to Analyze a
Flow Process Chart
Questions Related to Material
Questions Related to Operations and Inspections
Flow Process Chart
Is the delay avoidable?
What is the reason for the delay? Can the reason be eliminated?
Questions Related to Storage
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.
How can moves be shortened or eliminated by combining or eliminating
operations?
Can the level of mechanization in material handling be increased?
Questions Related to Delays
Is the operation time too high?
Is the inspection operation necessary?
Questions Related to Moves
Make or buy decisions: Should the part be produced in the factory or
purchased from an outside vendor?
Is the storage necessary?
Why can’t the material be move immediately to the next operation?
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.
Flow Process Chart
Unplanned
vs.
Planned
stoppage
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.
Worker Process Charts
Used to analyze the activities of a human
worker as (s)he performs a task that requires
movement around a facility.
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.
Form Process Charts
Used to analyze the flow of paperwork forms
and office procedures
Also known as process chart- person analysis
The symbols are the same as flow process
chart
Storage activity is omitted since it is difficult to
interpret in the context of human work activity
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.
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.
4
Flow Diagram
Flow Diagram
Drawing of the facility layout with the addition of lines
representing movement of materials or workers within
the facility
The flow diagram reveals problems in the work flow that
may not readily be identified using the process chart
alone.
Arrows on the lines represent direction of movement
For example, if the work flow involves considerable
backtracting, this can be identified in the flow diagram,
whereas it is indicated only as distances in the process
chart.
Often used in conjunction with a process chart
Operations, inspections, delays, and storages at specific
locations are identified by numbers referenced to the
activity number
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.
Flow Diagram
Flow diagram for worker
setting up a milling
machine:
Note the large number of
trips back and forth
between
the
milling
machine and the tool crib
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.
Shading Formats for Activity Charts
Thus, it can be used to detect excessive backtracking
(which might be missed in a process chart), excessive
travel, possible traffic congestion, points where delays
typically occur and inefficient layout.
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.
Activity Charts
A listing of the activities of one or more subjects (e.g.,
workers, machines) plotted against a time scale to
indicate graphically how much time is spent on each
activity
These activities are generally repetitive.
Types of activity charts:
Right-hand/left-hand activity chart (a.k.a. workplace activity
chart)
Worker-machine activity chart
Worker-multimachine activity chart
Gang activity chart (a.k.a. multiworker activity chart)
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.
Activity Chart
Instead of using symbols for the work activities, as in the other
charts, the activities are indicated by vertical lines or bars
Activity charts usually have more than one time scale
e.g., activity time and cumulative time
When bars are used, they are shaded or colored to indicate
the kind of the activity being performed.
Activity chart for a worker performing a repetitive task:
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.
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.
5
Multiple-Activity Charts
Used to track several participants working
together
They consists of multiple columns, one for
each participant.
Right-Hand/Left-Hand Activity Chart
Shows
contributions of the right and left hands
balance of the workload between the right and left
hands
Remember the example with pegs
Task involves placing pegs into a peg board
Note that left hand is used as a workholder
Objective: to analyze how the workload is
coordinated and shared among the entities.
Right-hand/left-hand activity chart
Worker-machine activity chart
Worker-multimachine activity chart
Gang activity chart (a.k.a. multiworker activity chart)
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.
Worker-Machine Activity Chart
Shows how work elements are allocated
between a worker and a machine
Help to identify opportunities for cycle time
improvements e.g., replacement of external
work elements by internal work elements
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.
Gang Activity Chart
This chart indicates activities in which two or
more workers performing together as a team
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.
Worker-Multimachine Activity Chart
Can be used to indicate machine interference
(when a machine must wait for service
because worker is currently servicing another
machine)
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.
Block Diagrams
Graphic consisting mostly of blocks and arrows
to portray the relationships among components
of a physical system
Also known as multiworker activity chart
Can be used to analyze the operations of
different stations in the the same chart
Objective: To better coordinate the activities
and balance the workload among the workers
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.
Commonly used in linear control theory, where
Arrows represent the flow of signals or variables in
the system
Blocks contain transfer functions that define how
input signals are mathematically transformed into
output signals
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.
6
Block Diagram
Process Maps
•Used to depict flows and interrelationships
among components in complex systems
•Block diagrams are commonly used in linear
control theory, as shown below for a feedback
control system
Output y
AB
= =
Input
x1 1 + AC
x2 = x1 − Cx3 , x3 = Ax2 x3 = Ax1 − ACx3
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.
Symbols in the Basic Process Map
A process is a sequence of tasks that add value to inputs
to produce outputs
Basic process map is a block diagram showing the steps
in a process
Widely applied to business processes
Also applicable to production, logistics, and service
operations
Levels of detail:
High-level process map – macroscopic view of
process and includes only the most important steps
Low-level process map – used to map each of the
steps in a high-level process map
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.
Basic Process Map
Process map symbols:
(a) beginning/ending point of the process,
(b) task or activity step,
(c) decision point
Symbols are connected by arrows to indicate
sequence
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.
Alternative Forms of Process Maps
Relationship process map – block diagram that
shows the input- output connections among
departments (or other functional components)
of an organization
Cross- functional process map – block diagram
showing how the steps of a process are
accomplished by various departments
Departments listed as rows separated by
dashed lines
Also called a swim
- lane chart
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.
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.
Relationship Map
Block diagram that shows the input- output
connections among departments (or other
functional components) of an organization
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.
7
Cross-Functional Process Map
Block diagram showing how the steps of a
process are accomplished by departments
Gantt Charts
A graphical display of
activities on a time axis
schedule
project
Project activities are listed on a vertical axis
Activity time durations are shown as horizontal
bars with starting and ending times
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.
Gantt Chart: Planned Activities
Shows planned activities for a construction project
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.
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.
Gantt Chart: Progress
Shows actual work accomplished at some
point during week 7
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.
Gantt Chart Showing Precedence
Arrows can be used to indicate precedence
relationships among activities
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.
8