charting and diagramming

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Work Systems and the Methods, Measurement, and Managementof Wor k

by Mikell P. Groover, ISBN0- 13-140650-7.

©2007 PearsonEducation, Inc., Upper Saddle River, NJ. Allri ghts reserved.

Charting and Diagramming

Sections:

1. Overview of Charting and Diagramming Techniques

2. Network Diagrams

3. Traditional Engineering Charting and DiagrammingTechniques

4. Block Diagrams and Process Maps

Gantt Charts ?

Chapter 9

Techniques for Operations Analysis

Work Systems and the Methods, Measurement, and Managementof Work

by MikellP. Groover, ISBN0-13-140650-7.

©2007 PearsonEducation, Inc., Upper Saddle River, NJ. Allrights reserved.

Objectives of Charts and Diagrams

Used in Methods Engineering

1. To permit work processes to be communicated and

comprehended more readily

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




How to Create / Develop the Chart or

Diagram?

Analyst is intimately familiar with the process anddevelops a graphic to represent it

Analyst observes and records information about theprocess

One-on-one interviews with those familiar with theprocess 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




How to Analyze the Chart or Diagram

Algorithmic analysis Line balancing, critical path methods

Checklists General questions applied to the particular process to

assess whether they can be applied to the problem of interest

Brainstorming Team activity in which participants contribute

recommendations

Separating value-added and non-value-added operations Value added steps:

1. Important to customer

2. Physically change the product or service




Checklist of Questions - Example What alternative starting material could be

used?

Should the part be produced or purchased?

Can this operation be eliminated, combined, or simplified?

Could a different joining method be used?

Could the inspection task be automated?




Categories of Charts and Diagrams1. Network diagrams

2. Traditional industrial engineering charts anddiagrams Operation charts

Process charts

Flow diagrams

Activity charts

3. Block diagrams and process maps

4. Gantt charts



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Network Diagrams

Consist of:

Nodes representing operations, work elements, activities or other entities

Arrows connecting the nodes indicates relationships among thenodes

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 =

( )2

1−nn




Network Diagram - Precedence Constraints

Restrictions on the order in which work

elements can be performed

Precedence

diagram




Traditional IE Charts and Diagrams

Operation charts

Process charts

Flow diagrams

Activity charts




Operation Charts

Graphical and symbolic representation of the operations usedto produce a product

The time to accomplish the operation is sometimes alsoincluded.

Two types of operations:

1. Processing and assembly operations

Changing the shape, properties or surface of amaterial or workpart

Joining two or more parts to form an assembly

2. Inspection operations Checking the material, workpart, or assembly for

quality or quantity







Operation Chart

Subassembly

Component



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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




Process Charts

Graphical and symbolic representation of the processingactivities performed either on something or by somebody.

The chart consists of a vertical list of activities using symbolsto represent operations, inspections, moves, delays andstorage and other activities.

Principal types of process charts:1. Flow process chart – analysis of a material or workpiece being

processed

2. Worker process chart – analysis of a worker performing a task

3. Form process chart – analysis of the processing of paperworkforms

All these charts are used to examine for possibleimprovements of operations




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







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



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Form for Flow Process Chart




Checklist of Questions Used to Analyze a

Flow Process Chart

Questions Related to Material

Make or buy decisions: Should the part be produced in the factory or purchased from an outside vendor?

Questions Related to Operations and Inspections Is the operation time too high?

Is the inspection operation necessary?

Questions Related to Moves 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 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 ne xt operation?




Flow Process Chart

Unplanned

vs.

Planned

stoppageWork Systems and the Methods, Measurement, and Managementof Work



Flow Process Chart




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

Storage activity is omitted since it is difficult to

interpret in the context of human work activity




Form Process Charts Used to analyze the flow of paperwork forms

and office procedures



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Multiple-Activity Charts

Used to track several participants workingtogether

They consists of multiple columns, one for each participant.

Objective: to analyze how the workload iscoordinated 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)




Right-Hand/Left-Hand Activity Chart

Shows

contributions of the right and left hands

balance of the workload between the right and lefthands

Remember the example with pegs

Task involves placing pegs into a peg board

Note that left hand is used as a workholder




Worker-Machine Activity Chart

Shows how work elements are allocatedbetween a worker and a machine

Help to identify opportunities for cycle timeimprovements e.g., replacement of externalwork elements by internal work elements




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)




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 activitiesand balance the workload among the workers




Block Diagrams Graphic consisting mostly of blocks and arrows

to portray the relationships among components

of a physical system

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 intooutput signals



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Block Diagram

AC

AB

x

y

Input

Output

+

==

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•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

31323312ACx Ax x Ax xCx x x −==−= ,




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 serviceoperations

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 thesteps in a high-level process map




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




Basic Process Map




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




Relationship Map Block diagram that shows the input- output

connections among departments (or other

functional components) of an organization



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Cross-Functional Process Map

Block diagram showing how the steps of a

process are accomplished by departments




Gantt Charts

A graphical display of schedule project

activities on a time axis

Project activities are listed on a vertical axis

Activity time durations are shown as horizontal

bars with starting and ending times




Gantt Chart: Planned Activities

Shows planned activities for a construction project




Gantt Chart: Progress

Shows actual work accomplished at some

point during week 7




Gantt Chart Showing PrecedenceArrows can be used to indicate precedence

relationships among activities

charting and diagramming

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