Just-In-Time and Lean Operations

*14 Principles of Toyota*

Principle No.Principle1Base your management decisions on a long term philosophy, even at the expense of short term financial goals2Create continuous process flow to bring problems to the surface3Use pull system to avoid overproduction4Level out the work load (Heijunka)5Build a culture of stopping to fix problems, to get quality right the first time6Standardized tasks are the foundation for continuous improvement and employee empowerment7Use visual control so that no problems are hidden

**14 Principles of Toyota*

Principle No.Principle8Use only reliable, thoroughly tested technology that serves your people and processes9Grow leaders who thoroughly understand the work, live the philosophy and teach it to others10Develop exceptional people and teams who follow your companys philosophy11Respect your extended network of partners and suppliers by challenging them and helping them improve12Go and see for your self to thoroughly understand the situation (Genchi Genbutsu)13Make decisions slowly by consensus, thoroughly by considering all options, but implement decisions rapidly14Become a learning organization through relentless reflection and continuous improvement (Keizen)

Taiichi Ohno, the vice president of Toyota Motor Company developed JIT concepts. JIT requires only necessary items be produced (or supplied) in necessary quantities at necessary times. Producing one unit extra is as bad as being one unit short. Completing production one day early is as bad as finishing one day late. Items are supplied only when needed or just-in-time.

Introduction

The major objective of JIT production is to eliminate waste. Waste has been defined as anything other than the minimum amount of equipment, materials, parts, space , and time which are absolutely essential to add value to the product. In short, waste is anything that does not add value.

Examples of WasteWaiting for partsCounting partsOver productionMoving parts over long distancesStoring inventoryMachine breakdownRework, etc.Looking for tools

*Sisih

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SentiasaAmal

JapanesewordsMalay WordsMeaningExampleSeiriSorting(Organization)Get rid of rubbishSeitonStraighten or Set in order(Orderliness)30-second retrieval of a documentSeisoSweeping(Clean up)Keep the work place clean so that the work can proceed smoothlySeiketsuStandardizing(Standardization)Transparency of storageShitsukeSustaining(Discipline )Practice 5-S in daily life

Basic Elements of JITSuppliersPull production systemCellular layoutInventoryScheduling (or kanban production system)Flexible work forcePreventive maintenance Quality at the source

A network of reliable and dependable suppliers is essential to JIT. Buyer and supplier should work together with mutual trust and there should be long term commitment. In order to develop long term commitment and reduce variability in the in coming materials, company needs to reduce number of suppliers. Further, supplier base should be as near to the buyer as possible.Suppliers

In push method, the production of the item begins in advance of customer needs. In pull method customer demand activates production of the item. In manufacturing sector, in a push system, a schedule is prepared in advance for a series of workstations, and each workstation pushes its completed work to the next station. With the pull system, workers go back to the previous stations and take only those parts or materials they need and process immediately.

Pull Production System

Pull Production SystemPull system prevents overproduction and under production. JIT uses pull system of production.

Cellular LayoutEnterWorker 1Worker 2Worker 3ExitKey:Product routeWorker routeMachines

Each month Security Pacific Corporations focussed facility sorts 7 million cheques, processes 5 million statements, and mails 190,000 customer statements. With a JIT layout, mail processing time has been reduced by 33%, salary costs by $tens of thousands per year, floor space by 50%, and in-process waiting lines by 75% to 90%. Storage including shelves and drawers have been removed. Result of JIT layout

Just-in-time inventory is the minimum inventory necessary to keep a system running. With just-in-time inventory, the exact amount of goods arrives at the moment it is needed, not a minute before or a minute later.Inventory

Type of problemsLate deliveriesLengthy setupsBad designsPoor qualityMachine breakdownIneffective layout

Some of the JIT inventory tactics are :

-- Use a pull system to move inventory-- Reduce lot size-- Develop just-in-time delivery system with the suppliers-- Deliver directly to the point of use-- Reduce set up time and thereby set up costs

-- It requires less space and less capital investment-- It reduces holding cost. -- Small lots cut lead times. Usually a large lot needs to wait longer to be processed.-- If any defective item is discovered, large lots cause longer delays because the entire lot must be inspected to find out the items that need rework. The task will be easier for small lots.-- Controlling task is easier for smaller lots.

Following are the advantages to keep smaller lot sizes:

Steps to Reduce Setup Time

JIT Scheduling Tactics

No.Tactic1Communicate the schedule to the suppliers2Make level schedule3Perform to the schedule4Seek one-piece make and one-piece move5Use kanbans

Kanban is the authorization for the next container of material to be produced. The purpose of kanban system is to signal the need for more parts and to ensure that those parts are produced in time to support subsequent fabrication or assembly. This is done by pulling parts through from the final assembly line.

Kanban

Kanban System

Kanban (Cards)

For an effective JIT system, quality of products must be very high, because there is no buffer inventory against defetive units. A poka yoke is any fool-proof device or mechanisms that prevents defects from occurring.Quality at the source

Flexible Work ForceMulti-skilled workersGeneral purpose equipments

Unplanned machine breakdown can disrupt the schedule.How frequently check-ups should be conducted? Collect the following data: -- Time between breakdown -- Frequency of breakdown -- Cost of breakdown -- Cost of preventive maintenancePreventive Maintenance

Preventive Maintenance -- An ExampleOne Deming prize winning company Aishin Seiki, has not experienced an equipment breakdown in more than four years. Prior to total preventive maintenance, they had more than 700 breakdowns in a month.

Is JIT dead?JIT inventory systems hold appealJIT: Zero toleranceJIT implementation: A survey on US manufacturing companiesApplications of JIT Principles

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