toyota production system 1

8/14/2019 Toyota Production System 1

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The Toyota Production System

High Quality and Low Cost

Readings;

James Womack, Daniel T. Jones and Daniel Roos,The Machine that Changed the World, 1990, Ch 3 and 4

Kenneth N. McKay, The Evolution of Manufacturing Control-

What Has Been, What Will Be Working Paper 03 2001

Michael McCoby, Is There a Best Way to Build a Car?HBR Nov-Dec 1997

COST VS

DEFECTS


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Consumer Reports


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Gains of imports


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Historical View

Performance measures

Elements of TPSDifficulties with Implementation

Six Eras of Manufacturing Practice


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Three Major Mfg Systems

from 1800 to 2000

1800 1900 2000

Machine tools, specialized machine tools, Taylorism, SPC, CNC, CAD/CAM

InterchangeableParts at U.S.

Armories

MassProductionat Ford

ToyotaProductionSystem


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Key Elements for New Mfg Systems

Japanese

Banks

Taiichi

Ohno

CNC,Integrationof Labor

Jobs,

Security

Post WarToyotaProductionSystem

EarningsHenry

Ford

Moving

AssemblyLine,etc

$5/day

Immigrant

Trans-

portation

Mass

Production

U.S.GovtRoswellLee/

John

Hall

MachineTools,

Division of

Labor

YankeeIngenuityMilitaryInterchange-able Parts

ResourcesLeaderEnablingTechnology

WorkForceMotivation

Need ofSociety

Element/

System


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Q. By what method did these

new systems come about?

A. Trial and Error


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History of the Development of the ToyotaProduction System ref; Taiichi Ohno

1945 1975


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Historical View





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Japanese Japanese in American in A ll Europei n J apa n North A me rica North A me rica

Performance:

Producvitity (hours/Veh.) 16.8 21.2 25.1 36.2

Quality (assembly

defects/100 vehicles) 60 65 82.3 97

Layout:

Space (sq.ft./vehicle/yr) 5.7 9.1 7.8 7.8

Size of Repair Area (as %

of assembly space) 4.1 4.9 12.9 14.4

Inventories(days for 8

sample parts) 0.2 1.6 2.9 2

Work Force:

% of Work Force in Teams 69.3 71.3 17.3 0.6

Job Rotation (0 = none,

4 = frequent) 3 2.7 0.9 1.9

Suggestions/Employee 61.6 1.4 0.4 0.4

Number of Job Classes 11.9 8.7 67.1 14.8

Training of New Production

Workers (hours) 380.3 370 46.4 173.3

Absenteeism 5 4.8 11.7 12.1

Automation:

Welding (% of direct steps) 86.2 85 76.2 76.6

Painting(% of direct steps) 54.6 40.7 33.6 38.2

Assembly(% of direct steps) 1.7 1.1 1.2 3.1

Source: IMVP World Assembly Plant Survey, 1989, and J. D. Power Initial Quality Survery, 1989

Summary of Assembly Plant Characteristics, Volume Producers,1989

(Average for Plants in Each Region)


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Cost Vs DefectsRef. Machine that Changed the World Womack, Jones and Roos


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Cost Vs AutomationRef. Machine that Changed the World Womack, Jones and Roos


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Historical View





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How do you get this kind of

performance?Womack, Jones and Roos

J T. Blacks 10 Steps

Demand Flow Technologys 9 Points


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Womack Jones and Roos

New Technology? No silver bullet

Automation?

Yes, but integrated with system Standardized Production?

Not in the usual dont stop the line sense

Lean Characteristics?

Integration of Tasks (opposite of deskilling) Identification and removal of defects (stop the line!)

kaizen institutionalizing change


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J T. Blacks 10 StepsRef; JT. Black Factory with a Future 1991

1. Form cells

2. Reduce setup

3. Integrate quality control

4. Integrate preventive maintenance5. Level and balance

6. Link cells KANBAN

7. Reduce WIP

8. Build vendor programs

9. Automate

10. Computerize


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Demand Flow Technologys

9 Points1. Product Synchronization

2. Mixed Model Process Maps

3. Sequence of Events

4. Demand at Capacity5. Operational Cycle Time

6. Total Product Cycle Time

7. Line Balancing

8. Kanbans9. Operational Method Sheets


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Current Value Stream Map


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Future Value Stream Map


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J T. Black 1, 2

1. Form Cells

Sequentialoperations, decouple

operator frommachine, parts infamilies, single pieceflow within cell

2. Reduce Setup

Externalize setup toreduce down-time

during changeover,increases flexibility


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TPS Cell

ToyotaC

ell,onepartisproduced

forevery

triparound

thecell

J T. Black


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Standardized Fixtures


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J T. Black 3, 4

3. Integrate qualitycontrol

Check part quality at

cell, poke-yoke, stopproduction whenparts are bad

4. Integrate preventivemaintenance

worker maintains

machine , runs slower


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J T. Black 5, 6

5. Level and balance

Produce to Takttime, reduce batch

sizes, smoothproduction flow

6. Link cells- Kanban

Create pull system Supermarket

System


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Balancing and Leveling

Balanced line: each process has the samecycle time. Match process time toassemble time, match production rate torate of demand (Takt time)

Leveled Line: each product is produced inthe needed distribution. The process must

be flexible to do this.


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J T. Black 7, 8

7.Reduce WIP

Make system reliable,build in mechanisms

to self correct

8. Build Vendorprogram

Propagate low WIP

policy to yourvendors, reducevendors, make on-time performance part

of expectation


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Some Basics Concepts of TPS

Smooth Flow and Produce to Takt Time

Produce to Order

Make system observable and correct

problems as they occur

Integrate Worker Skills

Institutionalize change


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Two Examples;

Takt Time

Pull Systems


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Takt Time:

demand time interval

DemandProduct

TimeAvailableTimeTakt =

Calculate Takt Time per month, day,year etc. Available time includes allshifts, and excludes all non-productive time (e.g. lunch, clean-upetc). Product demand includes over-production for low yields etc.


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Takt Time

Automobile Assembly Line; Available time = 7.5 hr X 3shifts = 22.5 hrs or 1350 minutes per day. Demand =

1600 cars per day.Takt Time = 51 sec

Aircraft Engine Assembly Line; 500 engines per year.2 shifts X 7 hrs => 14 hrs/day X 250 day/year = 3500hrs.

Takt time = 7 hrs.


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Engines shipped over a 3 month period

at aircraft engine factory B

0

2

4

6

8

10

12

7-Jun 15-Jun 23-Jun 30-Jun 7-Jul 15-Jul 24-Jul 31-Jul 7- Aug 15-Aug 24-Aug 31-Aug

Weeks

en

sp

p

we

month 1 month 2 month 3

Factory B


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Engines shipped over a 3 month periodat aircraft engine factory C

0

1

2

3

4

5

6

7

may june july augustweeks

enginesshipped

Factory C


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On-time performance of engine

plants

A B C0%

20%

40%

60%

80%

100%

enginesdelvered

A B C

on

time

late

on

time

on

time

late


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Push and Pull Systems

Machines

Parts Orders

1 2 3 4


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Push Systems Order (from centralized decision process) arrives at the front of the

system and is produced in batches of size B.Q. How long does it take to get one part out of the system?

1 2 3 N

Time = T3

Time = T2

Time = TN

Time = T1

Time = 0

..


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Push Systems

Time = 0

1 2 3 N

Time= TN

..

If the process time per part is t at each of

N processes, and the batch size is B,it takes time TN =NBt to getone part through the system.

Comment; Of course, thispart can come from inventoryin a much shorter time, but thepoint is that the push systemis not very responsive.


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Pull Systems-The order arrives at the end of the line and is pulled out of the

system. WIP between the machines allows quick completion.

Q.How long does it take to pull outone part?

A.The time to finish the last opetration t.


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Comparison between

Push and Pull SystemsPush system characteristics: Central

decision making, local optimization ofequipment utilization leads to largebatches, large inventories and a sluggishsystem.

Pull system characteristics: Local decision

making, emphasis on smooth flow,cooperative problem solving.

See HP Video


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HP Video

Dots Tacks Tape Pack

Inventory in the system = L

Time in the system = W

Littles Law L = W


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0.210.120.15Production Rate

= L / W

VisibleVisibleHiddenQuality Problem

31026Rework Units

WIP

0:191:403:17Cycle time = W

41230WIP = L

1 Table2 Tables2 TablesSpace

Pull (1)Pull (3)Push system (6)

HP Video Results


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So what are the advantages of

the pull systems? quick response low inventories

observable problems(if stopped = problem)

sensitive to state of the factory

(if no part = problem)

possible cooperative problem solving


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Historical View





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TPS Implementation

Physical part (machine placement,

standard work etc)

Work practices and people issues

Supply-chain part

Corporate Strategy (trust, job security)


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Work practices and people

issues Failed TPS attempts; GM Linden NJ,

CAMI, GM-Suzuki, Ontario Canada.

Successes GM NUMMI, Saturn. Toyota

Georgetown, KY See MacCoby article

Other Ref: Just Another Car Factory Rinehart,Huxley and Robertson, Farewell to the Factory,

Milkman


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Work practices and people

issues Innovative Work Practices Ref; C.Ichniowski, T. Kochan et al What

Works at Work: Overview and

Assessment, Industrial Relations Vol35 No.3 (July 1996)


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Examples of Innovative Work

Practices Work Teams

Gain Sharing

Flexible Job Assignments

Employment Security

Improved Communications


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What Works at Work: Overview

and Assessment, Conclusion 1; BundlingInnovative human resource management

practices can improve business productivity,

primarily through the use of systems of relatedwork practices designed to enhance workerparticipation and flexibility in the design of workand decentralization of managerial tasks and

responsibilities.


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and Assessment, Conclusion 3; Partial ImplementationA majority of contemporary U.S. businesses now

have adopted some forms of innovative work practices

aimed at enhancing employee participation such as workteams, contingent pay-for-performance compensation, orflexible assignment of multiskilled employees. Only asmall percentage of businesses, however, have adopteda full system of innovative work practices composed of

an extensive set of these work practice innovations.


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and Assessment, Conclusion 4; Barriers to ImplementationThe diffusion of new workplace innovations is limited,

especially among older U.S. businesses. Firms face a number ofobstacles when changing from a system of traditional work practices

to a system of innovative practices, including: the abandonment oforganization change initiatives after limited policy changes have littleeffect on performance, the costs of other organizational practicesthat are needed to make new work practices effective, long historiesof labor-management conflict and mistrust, resistance of supervisorsand other workers who might not fare as well under the newer

practices, and the lack of a supportive institutional and public policyenvironment.


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Barriers to Implementation

Early abandonment

Costs (training, commitment, benefits..)

History of conflict and distrust

Resistance of supervisors

Lack of supportive infrastructure


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Six Eras of Manufacturing

Practice, Ken McKayPioneeringSystemization

Technology and ProcessInternal Efficiency

Customer Service

Systems Level Re-engineering


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Ken McKay 1, 2

1. Pioneering - sellersmarket, competition isnot by manufacturing,

large marginsemphasizethroughput notefficiency

2. Systemization - firmgrows and system getscomplex, grossinefficiency becomes

apparent, competitionbegins to make itspresence felt. Need forstandard operatingprocedures, demand stillhigh, inventory used tobuffer against instabilities.


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Ken McKay 3, 4

3. Technology andProcess competition isincreasing, sales aresoftening, manufacturing

is still in early maturityand competition is limitedto firms in similarsituation. Product optionsgrow. Mfg focus shifts toefficiency.

4. Internal Efficiency -competition cherry pickersenter the market they dontoffer all of the options andparts service but focus on the

20% which yields 80% of therevenue stream. Internal plantis put into order, problems arepushed outside to suppliers,best in class, bench markingidentifies the silver bullet. Still

using inventory to cushionproduction support variety, andmaintain functional features.


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Ken McKay- 5, 6

5. Customer Service -talk to the

customer, identify

core competency,outsource, beresponsive, reducelead time, eliminate

feature creep,focused factory etc.

6. System Level Re-engineering - firmshave addressed theinternal system and

factory no more tosqueeze out look toimproving indirect andoverhead, supply chaindevelopment.


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Toyota Summary

High quality and low cost

Relationship to previous systems (seeMcKay paper), yet new,. in fact

revolutionary Many elements

Overall, see The Machine that Changed theWorld

Cells, next time

People, see Maccoby Article


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Summary .. continued

Autonomation automation with a human

touch

Worker as problem solver

TRUST

toyota production system 1

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