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Lean Manufacturing

Cellular ManufacturingOne Piece Flow for Workteams

Chapter 3Basic Elements of Cell Design

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Chapter 3 Overview

Phase 1 Understanding the Current Conditions

Collect Product and Production Data Document Current Layout and Flow

Time the Process

Calculate Process Capacity and Takt Time

Create Standard Work Combination Sheets

Phase 2

Converting to a Process-Based Layout Evaluate the Options

Plan Possible New Layouts

Move the Machines

Document the New Operating Procedures

Test to Confirm Improvement

Phase 3

Continuously Improving the Process

Shorten Cycle Times

Shorten Changeover Times

Eliminate Product Defects

Reduce Equipment Failures

Summary

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Converting Work Area into AManufacturing Cell

Understanding the current conditions

Converting to a process-based layout

Continuously improving the process

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Phase 1: Understanding the CurrentConditions

Helps the conversion team determine what process toconvert, and a base line to measure improvement.

Collect Product Data and Production Data

Product mix

Production resources (shifts, hours, employees, volume)

Document Current Layout and Flow

Process Route Analysis: helps to identify processing similarities

between different products and groups of products that could be

made in a cell.

Process Mapping Time The Process: Determine the value-added ratio. The value-

added ratio is the time spent actually machining or working on the

product divided by the total process lead time.

Calculate Process Capacity and Takt Time

Create Standard Work Combination Sheet

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Document the Current Process

Create Standard Work Combination Chart:

Graphical display for each operation in the process.

Depict the relationship between manual work time,

machine work time, and walking time for each stepin an operation as well as the non-cyclical time.

Draw a solid line to indicate the Takt time.

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Standard Work Combination Table -Definition

The Standard Work Combination Table combines human

movement and machine movement based on takt time and

is used as a tool to determine the range of work and work

sequence for which a team member is responsible.

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Human work and Machine work

The key notion (idea) for the elimination of waste and theeffective combination of work on the shop floor is the

separation of machine work and human work.

When we observe the work in which operators handle

machinery, then that work can be classified into machine orhuman work.

Understanding the separation of human and machine work

is the basis for understanding the interface between thesetwo elements.

If operators are merely observing the machine working then

this is the waste of Waiting and should be eliminated.

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Human work

This refers to work that cannot be completed without human

effort. For example,

picking up materials

putting materials onto a machine

operating the controls of a machine

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Machine work

This refers to work or incidental work that equipment, which

has been started by human hand, automatically performs

operations.

Milling

Auto riveting / bolting

Auto inspection

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Standard Symbols

Manual

AutomaticWalking

Waiting

The four basic symbols used in Standard work combination tables are:

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Walk

Manual Work

Wait

Takt

Time

HOW TO DISPLAY WORK ON THE

STANDARDISED WORK COMBINATION TABLE

Automatic Cycle

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HOW TO DISPLAY WORK ON THE

STANDARDISED WORK COMBINATION TABLE

TT

1

2,4

3,5

Returning to

the same process.

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Group Leader

STANDARDISED WORK COMBINATION TABLEPart Number / Name

123ABC / Widget LHTakt Time:162

Qty / shift: 169

OPERATING TIME IN MINUTESTIMEWORKSEQ OPERATION

TOTALSOperator

Wait time

MAN AUTO WALK

Manual

Process Machine and subassembly Cycle time

Available time:480 Supervisor

Prod/Engineer

Automatic

Walking

WaitingDepartment: Machine

Issue date 30/09/99

1 Select part A

2 Set into M/C 1

3 Start machine

4 Select part B

5 Set into jig

6 Select part C

7 Fit C to B

8 Set C/B to m/c 2

9 Start m/c

10 Remove A from m/c 1

11 Set A to jig

12Remove C/B from m/c

13 Screw C/B to A

14 Check torque

15 Put in finished bin

23

510

1520

2530

3540

4550

55 6570

7580

8560 90 100

95 105110

115120

125130

135140

145150

155160

10

1 842

9323

153

11

1 412

37

3

5 315

82

22

2

5

5

TTCT

95 125 34 33

129

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Phase 2: Converting to a Process-BasedLayout

Evaluate the Options: how to improve the four basic elementof production:

Methods

Machines

Materials

People Plan Possible New Layouts

Layout in the process steps is the basic principle

Machines placed close together

U or C shape

Often Counterclockwise (R/H next to machine) Move the Machines

Document the New Operating Procedures

Test to Confirm Improvement

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Phase 3: Continuously Improving theProcess

Rearranging the layout into a manufacturing cell is not really anend point - it is the beginning of continuous improvement

Look for problems that keeps the process from flowing:

Long cycle times

Product defects

Long changeover times

Equipment failures

Shorten Cycle Times

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Phase 3: Continuously Improving theProcess

Shorten Changeover Times

Single minute exchange of die (SMED) approach gives a three stage systemfor shortening setup:

1. Separate Internal and External Setup (can reduce setup time by 30-50 %)

Internal setup refers to setup operations that can be done only withthe equipment stopped

External setup can be done while the machine is working

Typical activities include:

Transporting all necessary tools and parts to the machine while it isstill running the previous job

Confirming the function of exchangeable parts before stopping themachine for changeover

2. Convert Internal Setup to External Setup

Standardized functions such as die height to eliminate the need foradjustments.

Using devises that automatically position the parts without measurement

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Phase 3: Continuously Improving theProcess

3. Streamline All Aspects of Setup

Using parallel operations, with two or more people working simultaneously

Using functional clamps instead of nuts and bolts

Using numerical setting to eliminate trial and error adjustments

Eliminate Product Defects

Mistake proofing/Zero Quality Control (ZQC)- zero defects

Reduce Equipment Failure

Total Productive Maintenance (TPM): is a comprehensive, company-wideapproach for reducing equipment related losses such as downtime, speedreduction, and defects by stabilizing and improving equipment conditions.

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Lean Manufacturing

Cellular ManufacturingOne Piece Flow for Workteams

Chapter 4

Teamwork Tools for Cellular Manufacturing

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Chapter 4 Overview

Working in Teams

Standardizing Workplace Conditions through 5S

Using Visual Management for Production Control

and Safety

Performing Autonomous Maintenance Activities

Using Activity Boards and One-Point Lessons

Summary

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Working in Teams

Success depends on teamwork

In a cell, people work together in new ways

Several operations are combined in a sequence, and themain job of the people working in the cell is to maintain a

smooth flow through the operations

Work must be coordinated

A group of employees has more creative potential and

energy than any person working on a problem alone

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Standardizing Workplace Conditionsthrough 5S

Cellular manufacturing cannot succeed in a workplace that iscluttered, disorganized or dirty

Establishing basic workplace conditions is essential in creating

a manufacturing cell

The 5S system is a set of five basic principles that have names

beginning with S:

Sort

Set in Order

Shine

Standardize

Sustain

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Using Visual Management for ProductionControl and Safety

Visual management is an important support for cellularmanufacturing

Visual management techniques express information in a

way that can be understood quickly by everyone

Sharing information through visual tools helps keep

production running smoothly and safely

One form of visual management in manufacturing cells is

the andon system: Individual machines or assembly stations are equipped with call

lamps

If the machine breaks down or run out of parts, the operator or the

machine turns on a light to call attention

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Using Visual Management forProduction Control and Safety

Visual location indicators help keep order in the workplace

Lines, labels, and signboards

Visual information can also prevent to make mistakes

Color coding

Matching color marks

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Performing Autonomous MaintenanceActivities

Activities carried out by shopfloor teams in cooperationwith maintenance staff

Element of Total Productive Maintenance (TPM)

Changes old view that operators just run machines andmaintenance people just fix them

Operators learn how to clean the equipment daily and how

to inspect it for trouble signs as they clean

Learn the equipment and assist with repairs

Team-based activity: work with maintenance technicians

and engineer

O

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Using Activity Boards and One-pointLessons

Two useful approaches for making information public A bulletin board or wall chart

Displays information about team activities and the results achieved

Chart improvement measures such as quality rate, On Time

Delivery, Overtime, Takt Rate, etc.

Helps keeping track of issues to follow up in the future

A one-point lesson

An easy to read poster to teach others about a particular problem

An improvement example, or Basic knowledge that everyone should have

Kept short and focused on one point

Often illustrated with photos or drawings

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Summary

Working in Teams

Standardizing Workplace Conditions through 5S

Using Visual Management for Production Control

and Safety

Performing Autonomous Maintenance Activities

Using Activity Boards and One-Point Lessons