toyota lean program

8/6/2019 Toyota LEAN Program

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J u s t . i n t i m e

,., .: ;, ~, J i d o k a

P r o d u d i o nK a i z e n

Sys tem Standa rd ized work


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The

To y o t aProduc t ion

System

Toyo ta Moto r Corpo ra t i on@E J

Tnlernational R.hlic Alfairs Division

OperaGons Mamgemetd Consultillg Division


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. . . . w . . . .+


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Introduction

P r o d u c t i v i t y,Quali ty. . .

And Des t iny

l Taking Our Destiny into Our Own Hands

l For Suppliers: Benefit or Burden?l A Historical Perspective on the Toyota

Production Systeml For Employees: Stimulating or Stressful?


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And lhe progress continues. Employees al Toyolaoperalions in Japan pl-oposed nearly Iwo millionimprovcmcnLs in IWO, and lhc employeesimplcmcn~ed 97% or their proposals. Employees atToyota operations outside J~apan are equally aclivc in

finding ways IO imptemen~ ~hc Tnyo~a ProtluclionSyswm more ellicienlly. So, 100, are theircountcrparlsal a growing number- of independenl suppliers.

The Toyola Protl~lclion Syslcm, lhcrc~orc, is aconlinuing slory. II is slit1 a sloly of advances inproduclivily and quality. It remains a sloty OFemployees designing their own jobs. And more thanever, it is a stoly of companics and individuals takingtheir deslinies into their own hands.


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0 0 1 0 0 0 1 0 0 0 1

The fixed-position stop system is a classicexample of jidoka. In that system, a workeranywhere on the assembly line who notices anabnormality can stop the production flow by

pulling on a rope overhead or by pushing abutton. Pulling on the rope or pushing thebutton lights a nutnbered lamp on a largeandon siynboard immediately to call (hesupervisors attention to the problem, and theline stops when it reaches the next fixedposition-the point at the end of onecomplete job. The supervisor rushes to thestation indicated on the signboard and helpscorrect the problem When the problerrl hasbeen resolved, the supervisor pulls Ihe rope toprevent the line from stoppirly-if iI has notalready reached the fixed positiorl--or to putit back in motion

We have two important reasons for keepingthe line moving until the next fixed positionafter a worker pulls on the rope overhead toindicate a problem. In most cases, that leavesenough time for the supervisor and workers toresolve the problem before the line comes to ahalt. If they do need more time to resolve theproblem, stopping the line at the fixedposition minimizes the disruption for the joh

sites along the line. That is because all the jobsites on the line process their work insynchrony with eactl other, and the fixedposition is a point where workers at each jobsite are between steps in their work. We thusavoid the errors and quality problelns thathappen all too easily when interruptions occurin the midst of work.

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Examples of Andon Signb oa rds

This andon is for a chassis line where peopleuse semiautomatic machinery to handle most

! ol the assembly work. A numbered lamp onIhis andon Itghts when an employee at the

machining shop. In this case, the numberedlamps on the andon go on when automatic

L_~r~~~~~~~inthe equipment detect a problem.


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Visual Control j

..~_.~~~~ ~~_...

Andon typify the principle of visualcontrol, which is crucial to jidoka and toevery aspect of the Toyota ProductionSystem. Employees and supervisors shouldbe able to grasp at a glance the state ofproduction in and around their worksite.They also must have immediate and easyaccess to all the information about theproper procedures for all the work that takesplace at each site.

photo--at many Toyota suppliers toemployees of the proper procedureshandling each kind of work.

It displyin Illisremindfor

Every vehicle on the assembly line carriessheets that display prominently all the relevantinformation about that vehicles specifications.People working on any part of the vehicle cansee and reconlirm easily what procedures and


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Fail-safe lealures are essential tojidoka. Some of those features consistof devices that set off warning lights

or buzzers to indicate a defectiveittm Others are design fcailrrcs toI)r(!v(:III (IIIIIII~~~W from ~~ssr!ml~ling1oo1s or workpieces incorrectly.

Jidoka ~1

Improvement tor preventmgemployees frommounting aspindlebackwards.

Before Kaizen After Kaizen

Jidoka improvement

Machine

U Spindle

14 h,. -


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Sensors (circled) for detecting whether a bodypanel is positioned properly on the lowermember of a pair of stamping dies. This dieand its mirror-image mate, which togetherweigh 22 tons, would crack easily if thestamping press were to slam them togetherwhen the workpiece was missing or positionedimproperly. The sensors prevent the press fromoperating when a body panel is not properly inplace and thus prevent costly refinishing oreven replacement.

Ji okaimprovement torpreventingworkpieces with amissing nut fromprogressmgfurther in theproductionsequence.


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Look up the wordjidokacasually in a Japanese-English dict ionary, and youll likely find a definition likeautomation. But look again. The kanji ideographs for thatjidoka areQ (ii), for self or auto: yl (dii).for movement or motion; andfL (ka). which corresponds to the-ationsuffix. Thats not the way theywrite jidoka-or thinkabout it-at Toyota.

The first and third kanji in thejidoka of the Toyota Production System are the same as in the genericJapanese word for automation. But the middle kanji,QII,differs in an important way. Though alsopronounced do,it means work. Note the additional element on the left side,f. By itself. A is thekanji for person. As part of another kanji. it suggests a human presence. So, with the addition of theideograph for person, the kanji for motion takes on the meaning work. Toyotasjidoka meansinvesting machines with humanlike intelligence.

Management and employees at Toyota share a very strong opinion about the roles of machines andpeople in their production system. They believe strongly in using machines in ways that makelife easier for employees at the worksite. For that to happen. the machines must have a built-in capacity for detecting abnormal events and responding accordingly. Thats why they put thej in $ BfK.


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Part 2

J u s t m i n - Ti m eProduc t ion

l Drafting and ImplemenlingProduction Plans

l Distributing Work Intelligentlyand Efficiently: Heijunka

l

Pulling Work through theProduction Sequence: Kunban

l An Unlikely Candidate for Famel Ensuring Orderly Transportation:

Mixed-Load Pickup and Deliveryl Continuous-Flow Processing


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The parts plant makes these axles for different kinds ofvehicles in the same sequence that the assembly plantwill make the vehicles that they will go into. Wemaintain that sequence in transporting the axlesbetween plants on the wagon you see here.


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Pulling Work through theProduction Sequence: K u n b a n

Kadxm are indispenmble tools fbr operating the just-h-time system. They @ditate an even {low ofproductior.l utrdan even distribution ofwovlc amorlg the di/rererlt stages of

processing and transport.


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2-l

Kanban FlowExample I Withdrawal Kanban

Team leaders gather the contents of themailboxes at prescribed times-several times aday-and place them in collection boxes. Thekanban postman picks the kanban up from thecollection boxes(c) and takes them to a sorting

(d), where an automatic sorter places thesnban in separate boxes for the different

d

An employee removes the kanban from a newstock of items when he or she uses the firstitem from that stock (Photo a) and deposits itin a kanban mailbox nearby(h).

A i hd l k b h i h id li I


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A withdrawal kanban that we use with an outside supplier. Itindicates the name of the supplier, the receiving area atToyota, the location in the plant where we will use the item,the part number, the part name, and the quantity. This kanbanalso has a bar code label to permit automatic invoicing.

A withdrawal kanbarl goesonto a new box of parts in

place of the productioninstructiorl kanban, whichcomes off and goes back intothe plant as a produclion orderfor a like quanlily of the samepart @). The supplier thendelivers the new box of parts tothe plant indicated on itskanban (/I).

The drivers that bring parts from the suppliersstop in at the sorting room (e) after unloadingtheir trucks and pick up kanban to take backto their plants, where they deposit them incollection boxes for subsequent sorting (0. f

2s


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Kanban Flow

Example 2Production Instruction Kanban

Boxes of finished parts at this Toyota supplier go onto arack to await pickup and delivery. Note the bright-colored markers. T-hey indicate which boxes to pick upfirst when there is more than one box of the same kindof part awaiting delivery. This first-in, first-out systemavoids the collection of dust and other problems thatran occrrr when items are left sittina. Shier nent orders,

Production at the supplier (below) proceeds inaccordance with the production instruction kanban(circled) that flow back to the manufacturing line in

correspondence with the pace that trucks have carriedaway shipments for delivery to Toyota plants.

_-.. ~-~ . .~,,~~ ~~~~~~of course, are in the form of withdrawal kanban. Thosekanban go onto the boxes in place of the productioninstruction kanban, and the production instructionksnban go back to the manufacturing line asproduction orders.


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Kanban cycles echo eachother throughout theproduction sequence.The materials that theemployees use at thissupplier each carry theirown withdrawal kanbanfor ordering additionalmaterials from thesuppliers suppliers.

Kanban do not need to be printed cards. They can be triangular metalplates and color-coded metal washers like those in these photos. They evencan be colored balls, like some processes at Toyota use.

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Nearly every part andassembly that movesthrough the ToyotaProduction Systemcarries a kanban.

We u:c tools brsides karlban 10 oper,llc OIH produtlio~~


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p , ptormal as a pull system When employet!s at ~hc wol~ksileat the left have used the 7th body panel in their stock,they push the button correspondiny to that kind of panelon the eleclric console (arrow). That lights a lamp on asignboard on the other side of the plant, where a lorklifloperalor (Mow) then picks up and delivers a new \lockof body panels.

The homely kanban is an unlikely candidate for fame. Though its name means signboard in Japanese.the kanban is no marquee. Kanban at Toyota are usually no more than printed pieces of cardboardsandwiched between clear plastic covers. Yet these nondescript items have become the best-knownclement of the Toyota Production System. Some people even think that the kanban system is the ToyotaProduction System

Actually, the kanban is a tool that enables employees to operate the Toyota Production System bytaking responsibility for managing their own jobs. Envision an employee who removes kanban from

components before mounting them on vehicles. The employee sends the kanban back to the precedingprocess as orders for additional components to replace the ones he or she has used. That employee isshouldering an important part of the management function of ordering parts and managing inventory.

Employees use kanban to monitor continuously-by sight-the material that they withdraw frompreceding processes and the finished items that they pass on to the next process. The employees thusmanage the flow of their own work in accordance with the established work procedures for that work. And it is the employees themselves who establish the work procedures.

Every large assembly shop at Toyota has two or more kanban stations, each of whichprocesses about10.000 kanban per shift. Suppliers affix identifying kanban to the items they deliver. And they receiveorders via kanban that they remove from boxes at the stations on their way out. The paperwork isminimal, The efficiency is maximal. And the employees themselves are completely in charge.

I2)


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Ensuring Orderly Transportation:Mixed-Load Pickup and Delivery

The pull system is an excellent way to minimize inventories and prevent waste. But its efficiency depends on transporting parts in an orderly and timely manner.

Most transport between Toyota plants and suppliers need for diverse items in relatively small quantities bytakes plncc in a lixcd-volume Format-a shipment using a format called scheduled-time, mixed-load,moves when enough ol-ders accumulate Lo result in a h.equent transportation. The diagrams on t~his pagefu11 tmck. Sometimes, however, WC accommodate the illustrate how that format works.

Formerly, each parts plant would carry parts directly to an assemblyplant once or twice a day. That meant keeping a full days or a half-days inventory at each parts plant and also at the assembly plant.

L.~_____..~..~__~

Now, a single truck picks up parts at multiple parts plants on the wayto the assembly plant. Trucks each carry a variety of parts, and theymake deliveries and receive kanban orders three times a day; so,

inventories are smaller at the parts plants and at the assembly plant.


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Advantages of Handling items One at a The

In the figures on these two pages, Employees A, B, andC perform successive steps in an assembly sequence.

Work begins for each employee in the example belowwith receiving a box of 100 semifinished assembliesfrom the previous process. They perform additionalwork on each of the assemblies and then take their100 assemblies to the next employee on thef~roductiori line.

.~~ ~..

Separately Positioned Processing

_._.~~ ._.~ .~_....~~ ~.__~ .._~ _..~~ .~._

This approach entails the following inefficiencies:

Each employee has 100 items at a time, whichresults in.exiremely long lead times.It is impossible to balance the distribution of workbetween employees.The large amount of items per employee meansextra handling on the workbench employeesspend a lot of time picking up parts that fall ontothe floor; with delicate items, they must take timeto stack the items carefully.If Ernployee B discovers that a workpiece fromEmployee A is not assembled properly, shecannot determine immediately where the problemoccurred, since it occurred during the processrngof 100 items.When production shifts to a different kind ofassembly, the employees rnust remove all the partsfor the previous assembly from the shelves toavoid mixing them with the parts for the newassembly

_~ __~. -~ -

We can avoid the problems that occur in the example the number of employees on the line.


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We can avoid the problems that occur in the exampleat the left by deploying the employees next to eachother in a continuous flow and by having eachemployee handle one assembly at a time. Theyperform their work on an assembly and hand it overto the next employee before reaching for the nextworkpiece.

This change, which requires no increase in the

number of employees for the same span of work,yields the following improvements:I, The number of items on the line-from raw

material to finished product-becomes the same as

the number of employees on the line.2. When Employee B discovers a defective item, she

and Employee A can determine the cause of theproblem immediately, since it is the item thatEmployee A has just handled.

3. Employees neednt arrange and convey largenumbers of parts on the workbench.

4. Differences in work loads between employees are

readily apparent, and we often can find ways toreduce our manpower needs.5. We can switch production to different items

without interrupting the production flow.

Continuous-Flow Processing

Materials Finishedproducts

7

l-he real difference in lead time between one-at-a-time production and conventional lot production

Processing Parts One at a TimelWV


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The photo shows a bench for dies that a Toyotasupplier installed beside a stamping machine.Without the bench, die set-up meant spending20 minutes carrying the old die back to storageand bringing out the new die. That is too longfor a machine to be idle. Now, employees canbring the new die up and set it on the benchwhile the machine is still running.

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Here is another example of shortening set-uptime. Positioning is a key step in replacing dies.The machine operators must position thecushion pin and die carefully before locking thedie in place. 50 we fitted machines with guidesto allow for mountina and oositionina die


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Part 3


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Part 3

Standa rd i zedWork andKaizen

l Dua l Dyna mics o f t h e ToyotaP r o d u c t i on S ys t e m

l Works i t e M a n a g e m e n tl P r o m o t in g I m p r o v e m e n t s o n a

Con t inu ing Bas i s: Kuizenl K a i z e n -N e v e r To o M u c h


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guidelines. The team leader at each worksite is incharge of standardized work Car his or her team. He or

llexiblc and subject to continuing modification attdimprovement, Team leaders and the member-s 01 their


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gshe assigns work in accordance with the monthlyproduction schedule and with the teams capacity.

The standardized work changes in reflection ol themonthly changes in pl-oduction, and employees mustbe able to respond flexibly. ~vety employee must knowat least how IO pe&rm the jobs in 111~ p-ocesses

immediately beLot-e and after his or her own process inthe production sequence.

Just as employees need to be versatile in the ToyotaProduction System, the standardized work itsell is

p ,teams are li-ee IO adjust working sequences asnecessary. They do that to resolve p~~oblrrns that occutand also lo implement ideas they have lot- makingimpt-ovements. That is why the continuingimprovements-kaiT.en-are so vcty essential tostandanlized work.

Irn n.-

.,.....~~Operation Standards Sheet


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The biggest difference between the Toyota Production System and conventional mass-productionformats is the large amount of responsibility and authority that the former assigns to employees at eachworksite. A commitment to the workplace is a tradition at Toyota. It was the founder of Toyotasautomobile operations, Kiichiro Toyoda. who often said that any engineer who didnt get his hands dirtyat least three times a day was no engineer at all. Today, the workplace remains the seat of management

authority for production operations at Toyota.Numerous features of the Toyota Production System are tools for enabling employees to manage as

many functions as possible right at their worksites. Kanban are a prominent example. So are thestandardized work charts that outline each job clearly.

Visual control is vital toworksite management.. Everyone must be able to see easily and immediately if work is proceeding smoothly and on s chedule. Numbered lamps on large display panels indicate at aglance if and where any employee in the plant has indicated a problem by using a line-stop button or rope. Line-stop clocks indicate to the second the aggregate down time for the day. Performance analysisboards show the status of production in relation to goals.

Worksite management is for executives at Toyota, as well as for line employees. Members of management remain true to their roots in production and marketing, where most of them begin their

careers. Top executives make frequent visits to the workplace-plants, suppliers, dealers-to check onthe progress of work with their own eyes. And they act on what they see.


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_.... _ ._.., _. _._._. ._ . ..

O t h e r r e g i o n s

The Toyota Production System at work


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The Toyota Production System at workin South Africa.


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Producing seats for locally manufactured Toyotas in Taiwan

Making Toyota passenger cars in Australia

I

Afterword


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The Toyota Production System, as noted elsewhere in thisbook, continues to evolve in response to changing needsand circumstances. The increasingly global scope ofToyotak operations will occasion further evolution in thesystem in the 1990s.

The mo st c onspicuo us issue for the Toyo ta Produc tionSystem is the growing role of o versea s operations inour business. That glob al scop e ma nda tes a glo ba lperspec tive on p roduction, logistics, and technology.

WC need to rethink tile traditional division of laborbetween domestic and overseas operations. We willneed to create a Ial-ger role lo r overseas employees inour organizations. We also will need to invest o utoverseas operations wit11 integraled capabilities inproducliotl and in t cc fmolog ica l rlovclopn~ent,including &sign work.

This cha llenge relalcs to the entire pl-ocess OFpt-educing and transporting vehicles. We need toshorten lead times ancl reduce costs at ev&ly stage,I1-om th e initial processing of raw materials throughthe production and Irnnspol-tation o l pal-Is to lhcassemb ly a nd delivery o l linislled vehicles.

On e key lo mceling lhat challcngc will hc 10 upgl~adc

toyota lean program

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