Charting and Diagramming
Techniques for Operations Analysis
Chapter 9
Sections:
1. Overview of Charting and Diagramming Techniques
2. Network Diagrams
3. Traditional Engineering Charting and Diagramming
Techniques
4. Block Diagrams and Process Maps
Gantt Charts ?
1
Objectives of Charts and Diagrams
Used in Methods Engineering
1. To permit work processes to be communicated and
comprehended ‫استوعب‬more readily ‫بسهولة‬
2. To use algorithms specifically designed for the particular
diagramming technique
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
2
How to Create / Develop the Chart or
Diagram?
 Analyst is familiar with the process and develops a
graphic to represent it
 Analyst observes and records information about the
process
 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
3
How to Analyze the Chart or Diagram

Algorithmic analysis


Checklists


General questions applied to the particular process to
assess whether they can be applied to the problem of
interest
Brainstorming


Line balancing, critical path methods
Team
activity
in
recommendations
which
participants
contribute
Separating value-added and non-value-added operations
4
Categories of Charts and Diagrams
1. Network diagrams
2. Traditional industrial engineering charts and
diagrams




Operation charts
Process charts
Flow diagrams
Activity charts
3. Block diagrams and process maps
4. Gantt charts
5
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):
Maximum number of arrows = n (n -1)

One-way arrows (precedence):
Maximum number of arrows =
n n  1
2
6
Network Diagram - Precedence Constraints
 Restrictions on the order in which work
elements can be performed
Precedence
diagram
7
2. Traditional IE Charts and Diagrams
 Operation charts
 Process charts
 Flow diagrams
 Activity charts
8
2.1 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:
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
9
Operation Chart
‫ثقب‬
‫حز‬
Component
Subassembly
10
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
o What alternative starting material could be used?
o Make or buy decision: should the part be produced in the
factory or purchased?

Questions related to operations
o Is this processing operation necessary?
o Can this operation be eliminated, combined, or simplified?
o Could a different joining method be used?

Questions related to inspection
o Is this inspection necessary?
o Could the inspection task be automated?
11
Operation Charts
12
2.2 Process Charts

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
possible
13
2.2.1 Flow Process Chart
 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
14
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
15
Form for Flow Process Chart
16
Checklist of Questions Used to Analyze a
Flow Process Chart

Questions Related to Material


Questions Related to Operations and Inspections




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 delay avoidable?
What is the reason for the delay? Can the reason be eliminated?
Questions Related to Storage


Is the storage necessary?
Why can’t the material be move immediately to the next operation?
17
Flow Process Chart
18
Flow Process Chart
19
2.2.2 Worker Process Charts
 Used to analyze the activities of a human
worker as (s)he performs a task that requires
movement around a facility.
 Also known as process chart-person analysis
 The symbols are the same as flow process
chart
o Storage activity is omitted since it is difficult to
interpret in the context of human work activity
20
2.2.3 Form Process Charts
 Used to analyze the flow of paperwork forms
and office procedures
21
2.3 Flow Diagram
 Drawing of the facility layout with the addition of lines
representing movement of materials or workers within the
facility
 Arrows on the lines represent direction of movement
 Often used in conjunction with a process chart
o Operations, inspections, delays, and storages at specific
locations are identified by numbers referenced to the activity
number
 The flow diagram reveals problems in the work flow that
may not readily be identified using the process chart alone.
 It can be used to detect excessive backtracking, excessive
travel, possible traffic congestion, points where delays
typically occur and inefficient layout.
22
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
23
2.4 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:
o Right-hand/left-hand activity chart (workplace activity
chart)
o Worker-machine activity chart
o Worker-multimachine activity chart
o Gang ‫جماعة‬activity chart (multiworker activity chart)
24
Shading Formats for Activity Charts
 Instead of using symbols for the work activities, as in the other
charts, the activities are indicated by vertical lines or bars
 When bars are used, they are shaded or colored to indicate
the kind of the activity being performed.
25
Activity Chart
Activity charts usually have more than one time scale
e.g., activity time and cumulative time
Activity chart for a worker performing a repetitive task:
26
Multiple-Activity Charts
 Used to track several participants working
together
 They consists of multiple columns, one for
each participant.
 Objective: to analyze how the workload is
coordinated and shared among the entities.
27
2.4.1 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
28
2.4.2 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
29
2.4.3 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)
30
2.4.4 Gang Activity Chart
 This chart indicates activities in which two or
more workers performing together as a team
 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
31
Process Maps
 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
34
Symbols in the 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
35
Basic Process Map
36
Alternative Forms of Process Maps
 Relationship process map
 Cross-functional process map
37
Relationship process Map
 Block diagram that shows the input-output
connections among departments (or other
functional components) of an organization
38
Cross-Functional Process Map
 Block diagram showing how the steps of a process are
accomplished by departments
 Departments listed as rows separated by dashed lines
39
4. 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
40
Gantt Chart: Planned Activities
Shows planned activities for a construction project
41
Gantt Chart: Progress
Shows actual work accomplished at some
point during week 7
42
Gantt Chart Showing Precedence
Arrows can be used to indicate precedence
relationships among activities
43