JIT

Just – In - TimeJust – In - Time

JITJIT

April 7, 2023April 7, 2023 Prof. Vivek KumarProf. Vivek Kumar 22

TAIICHI OHNOTAIICHI OHNO

Born in 1912, Taiichi Ohno who Born in 1912, Taiichi Ohno who joined TOYOTA in 1943 and then joined TOYOTA in 1943 and then went about realising Toyada went about realising Toyada Kiichiro (1894 – 1952)’s dream to Kiichiro (1894 – 1952)’s dream to catch up with America in three catch up with America in three years. Otherwise, the automobile years. Otherwise, the automobile industry of Japan will not survive.industry of Japan will not survive.

Creator of Just-In-Time



At the time of Japanese surrender At the time of Japanese surrender on August 15, 1945. Taiichi Ohno on August 15, 1945. Taiichi Ohno who was working with Toyota who was working with Toyota Motor Company found out that the Motor Company found out that the productivity of Japanese to productivity of Japanese to American worker was 1:9.American worker was 1:9.




To bridge this gap, they set about To bridge this gap, they set about working on developing the new working on developing the new system on two pillars:system on two pillars:

Just – In – TimeJust – In – Time AutonomationAutonomation(automation with a human touch)(automation with a human touch)



Just-in-Time LogicJust-in-Time Logic

Nothing is produced until it is Nothing is produced until it is needed. Need is created by needed. Need is created by demand. In theory, when an item is demand. In theory, when an item is sold, the market pulls another item sold, the market pulls another item from the last position in the system, from the last position in the system, this triggers an order to the this triggers an order to the production line, where the worker production line, where the worker pulls another item from an upstream pulls another item from an upstream station to replace the item taken.station to replace the item taken.


JIT demands a high levels of JIT demands a high levels of quality at each stage of the quality at each stage of the process, strong vendor relations process, strong vendor relations and predictable demand for the and predictable demand for the end product.end product.

Just-in-Time LogicJust-in-Time Logic


DefinitionDefinition

A Structural approach in a A Structural approach in a manufacturing organization manufacturing organization focused on improving Timeliness, focused on improving Timeliness, Quality, Productivity and Flexibility Quality, Productivity and Flexibility utilizing various methods of Work utilizing various methods of Work Simplification and Waste Simplification and Waste Reduction.Reduction.

Shigeo Shingo



Originator of JIT philosophy and Originator of JIT philosophy and the man behind the success of the man behind the success of ‘TOYOTA’ relentlessly pursued for ‘TOYOTA’ relentlessly pursued for total elimination of waste. He total elimination of waste. He identified the following seven identified the following seven wastes:wastes:


Seven WastesSeven Wastes

1.1. Waste arising from Waste arising from overproducing.overproducing.

2.2. Waste arising from time on Waste arising from time on hand (waiting).hand (waiting).

3.3. Waste arising from Waste arising from transporting.transporting.

4.4. Waste arising from processing Waste arising from processing itself.itself.


Seven WastesSeven Wastes

5.5. Waste arising from Waste arising from unnecessary stock on hand.unnecessary stock on hand.

6.6. Waste arising from Waste arising from unnecessary motion.unnecessary motion.

7.7. Waste arising from producing Waste arising from producing defective goods.defective goods.


Principles of HousekeepingPrinciples of Housekeeping

The 5 S’s:The 5 S’s: Proper Selection Proper Selection (SERI)(SERI) Proper Arrangement Proper Arrangement (SEITON)(SEITON) Cleaning Cleaning (SEISO)(SEISO) Cleanliness Cleanliness (SEIKETSU)(SEIKETSU) Self Discipline Self Discipline (SHITSUKE)(SHITSUKE)


JIT’s PresumptionsJIT’s Presumptions

The importance of JIT is to The importance of JIT is to eliminate waste. The main objective eliminate waste. The main objective is to develop a system that allows a is to develop a system that allows a manufacturer to have only the manufacturer to have only the materials, equipment and people on materials, equipment and people on hand required to do a job. However, hand required to do a job. However, the system presupposes that in the system presupposes that in order to achieve its goals order to achieve its goals companies will try to fulfill the companies will try to fulfill the objective requirements such as:objective requirements such as:



Vertical integration and optimizing Vertical integration and optimizing the step of manufacturing process.the step of manufacturing process. Processing quality products.Processing quality products. Low cost operation with its Low cost operation with its advanced technology machinery.advanced technology machinery. Producing product based on Producing product based on demand.demand.



Manufacturing flexibility.Manufacturing flexibility. Good reputation with suppliers & Good reputation with suppliers & customers.customers. Spotlighting improvement areas.Spotlighting improvement areas.


JIT ManufacturingJIT Manufacturing

Keeps inventory low or at 0.Keeps inventory low or at 0. Raw materials (only enough to Raw materials (only enough to supply 1supply 1stst step in process). step in process). Each Station in succession Each Station in succession produces enough for the next produces enough for the next Station.Station. Final Product Inventory enough Final Product Inventory enough to supply customer requests.to supply customer requests.


JIT MethodsJIT Methods

1.1. Elimination of WasteElimination of Waste2.2. Good HousekeepingGood Housekeeping3.3. Visual ControlVisual Control4.4. Jidoka / Andon / PokayokeJidoka / Andon / Pokayoke5.5. Machine Total Productive Machine Total Productive

MaintenanceMaintenance6.6. Material Handling / Material Handling /

TransportationTransportation


JIT MethodsJIT Methods

7.7. Set – up reductionSet – up reduction8.8. Demand Pull + KANBANDemand Pull + KANBAN9.9. SchedulingScheduling10.10. Supplier RelationsSupplier Relations11.11. Traditional Batch vs. JITTraditional Batch vs. JIT


JIT and Lean ManagementJIT and Lean Management JIT can be divided into two terms: JIT can be divided into two terms:

“Big JIT” and “Little JIT”“Big JIT” and “Little JIT” Big JITBig JIT (also called (also called Lean Lean

ManagementManagement) is a philosophy of ) is a philosophy of operations management that seeks to operations management that seeks to eliminate waste in all aspects of a eliminate waste in all aspects of a firm’s production activities: human firm’s production activities: human relations, vendor relations, relations, vendor relations, technology, and the management of technology, and the management of materials and inventorymaterials and inventory

Little JITLittle JIT focuses more narrowly on focuses more narrowly on scheduling goods inventory and scheduling goods inventory and providing service resources where providing service resources where and when neededand when needed


JIT Demand-Pull LogicJIT Demand-Pull Logic

Customers

Sub

Sub

Fab

Fab

Fab

Fab

Vendor

Vendor

Vendor

Vendor

Final Assembly

Here the customer starts the process, pulling an inventory item from Final Assembly…

Then sub-assembly work is pulled forward by that demand…

The process continues throughout the entire production process and supply chain


Minimizing Waste: Focused Minimizing Waste: Focused Factory NetworksFactory Networks

CoordinationSystem Integration

These are small specialized plants that limit the range of products produced (sometimes only one type of product for an entire facility)

Some plants in Japan have as few as 30 and as many as 1000 employees


Minimizing Waste: Minimizing Waste: Group TechnologyGroup Technology (Part 1)(Part 1)

Using Using Departmental SpecializationDepartmental Specialization for plant layout can cause a lot of for plant layout can cause a lot of unnecessary material movement unnecessary material movement

Saw Saw

Lathe PressPress

Grinder

LatheLathe

Saw

Press

Heat Treat

Grinder

Note how the flow lines are going back and forth

Minimizing Waste: Group Technology Minimizing Waste: Group Technology (Part 2)(Part 2)

Revising by using Revising by using Group Technology CellsGroup Technology Cells can reduce movement and can reduce movement and improve product flow improve product flow

Press

Lathe

Grinder

Grinder

A

2

BSaw

Heat Treat

LatheSaw Lathe

PressLathe

1


Minimizing Waste: Minimizing Waste: Uniform Plant Loading (heijunka)Uniform Plant Loading (heijunka)

Not uniform Jan. Units Feb. Units Mar. Units Total

1,200 3,500 4,300 9,000

Uniform Jan. Units Feb. Units Mar. Units Total

3,000 3,000 3,000 9,000

Suppose we operate a production plant that produces a single product. The schedule of production for this product could be accomplished using either of the two plant loading schedules below.

How does the uniform loading help save labor costs?

or


Minimizing Waste: Just-In-Time Minimizing Waste: Just-In-Time ProductionProduction

• Management philosophy• “Pull” system though the plant

WHAT IT IS

• Employee participation• Industrial engineering/basics• Continuing improvement• Total quality control• Small lot sizes

WHAT IT REQUIRES

• Attacks waste• Exposes problems and bottlenecks• Achieves streamlined production

WHAT IT DOES

• Stable environment

WHAT IT ASSUMES

Minimizing Waste: Inventory Minimizing Waste: Inventory Hides ProblemsHides Problems

Work inprocess queues(banks)

Changeorders

Engineering designredundancies

Vendordelinquencies

Scrap

Designbacklogs

Machine downtime

Decisionbacklogs

Inspectionbacklogs

Paperworkbacklog

Example: By identifying defective items from a vendor early in the production process the downstream work is saved

Example: By identifying defective work by employees upstream, the downstream work is saved

Minimizing Waste: Kanban Minimizing Waste: Kanban Production Control SystemsProduction Control Systems

Storage Part A

Storage Part AMachine

Center Assembly Line

Material Flow

Card (signal) Flow

Withdrawal kanban

Once the Production kanban is received, the Machine Center produces a unit to replace the one taken by the Assembly Line people in the first place

This puts the system back were it was before the item was pulled

The process begins by the Assembly Line people pulling Part A from Storage

Production kanban


Determining the Number of Kanbans Determining the Number of Kanbans NeededNeeded Setting up a kanban system Setting up a kanban system

requires determining the number requires determining the number of kanbans cards (or containers) of kanbans cards (or containers) neededneeded

Each container represents the Each container represents the minimum production lot sizeminimum production lot size

An accurate estimate of the lead An accurate estimate of the lead time required to produce a time required to produce a container is key to determining container is key to determining how many kanbans are requiredhow many kanbans are required


The Number of Kanban Card SetsThe Number of Kanban Card Sets

CSDL

k

)(1

container theof SizestockSafety timelead during demand Expected

k = Number of kanban card sets (a set is a card)D = Average number of units demanded over some time periodL = lead time to replenish an order (same units of time as demand)S = Safety stock expressed as a percentage of demand during leadtimeC = Container size


Example of Kanban Card Example of Kanban Card Determination: Problem DataDetermination: Problem Data A switch assembly is assembled in A switch assembly is assembled in

batches of 4 units from an “upstream” batches of 4 units from an “upstream” assembly area and delivered in a special assembly area and delivered in a special container to a “downstream” control-container to a “downstream” control-panel assembly operationpanel assembly operation

The control-panel assembly area The control-panel assembly area requires 5 switch assemblies per hourrequires 5 switch assemblies per hour

The switch assembly area can produce a The switch assembly area can produce a container of switch assemblies in 2 container of switch assemblies in 2 hourshours

Safety stock has been set at 10% of Safety stock has been set at 10% of needed inventoryneeded inventory


Example of Kanban Card Determination: Example of Kanban Card Determination: CalculationsCalculations

3or ,75.24

5(2)(1.1))(1

container theof SizestockSafety timelead during demand Expected

CSDL

k

Always round up!


Respect for PeopleRespect for People

Level payrollsLevel payrolls

Cooperative employee unionsCooperative employee unions

Subcontractor networksSubcontractor networks

Bottom-round management styleBottom-round management style

Quality circles (Small Group Quality circles (Small Group Involvement Activities or SGIA’s)Involvement Activities or SGIA’s)


Toyota Production System’s Four Toyota Production System’s Four RulesRules

1.1. All work shall be highly specified as to All work shall be highly specified as to content, sequence, timing, and outcomecontent, sequence, timing, and outcome

2.2. Every customer-supplier connection Every customer-supplier connection must be direct, and there must be an must be direct, and there must be an unambiguous yes-or-no way to send unambiguous yes-or-no way to send requests and receive responsesrequests and receive responses

3.3. The pathway for every product and The pathway for every product and service must be simple and directservice must be simple and direct

4.4. Any improvement must be made in Any improvement must be made in accordance with the scientific method, accordance with the scientific method, under the guidance of a teacher, at the under the guidance of a teacher, at the lowest possible level in the organization lowest possible level in the organization


JIT Implementation Requirements: JIT Implementation Requirements: Design Flow ProcessDesign Flow Process Link operationsLink operations Balance workstation capacities Balance workstation capacities Redesign layout for flow Redesign layout for flow Emphasize preventive Emphasize preventive

maintenance maintenance Reduce lot sizes Reduce lot sizes Reduce setup/changeover time Reduce setup/changeover time


JIT Implementation Requirements: JIT Implementation Requirements: Total Quality ControlTotal Quality Control

Worker responsibility Worker responsibility

Measure SQC Measure SQC

Enforce compliance Enforce compliance

Fail-safe methods Fail-safe methods

Automatic inspectionAutomatic inspection


JIT Implementation Requirements: JIT Implementation Requirements: Stabilize ScheduleStabilize Schedule

Level schedule Level schedule

Underutilize capacityUnderutilize capacity

Establish freeze windowsEstablish freeze windows


JIT Implementation Requirements: JIT Implementation Requirements: Kanban-PullKanban-Pull

Demand pull Demand pull

Backflush Backflush

Reduce lot sizesReduce lot sizes


JIT Implementation Requirements: JIT Implementation Requirements: Work with VendorsWork with Vendors

Reduce lead times Reduce lead times

Frequent deliveries Frequent deliveries

Project usage requirements Project usage requirements

Quality expectations Quality expectations


JIT Implementation Requirements: JIT Implementation Requirements: Reduce Inventory MoreReduce Inventory More

Look for other areasLook for other areas

Stores Stores

TransitTransit

CarouselsCarousels

Conveyors Conveyors


JIT Implementation Requirements: JIT Implementation Requirements: Improve Product DesignImprove Product Design

Standard product Standard product configuration configuration

Standardize and reduce Standardize and reduce number of partsnumber of parts

Process design with product Process design with product design design

Quality expectationsQuality expectations


JIT Implementation Requirements: JIT Implementation Requirements: Concurrently Solve ProblemsConcurrently Solve Problems

Root causeRoot cause Solve permanentlySolve permanently

Team approachTeam approach

Line and specialist Line and specialist responsibilityresponsibility

Continual education Continual education


JIT Implementation Requirements: JIT Implementation Requirements: Measure PerformanceMeasure Performance

Emphasize Emphasize

improvement improvement Track trendsTrack trends


JIT in Services (Examples)JIT in Services (Examples)

Organize Problem-Solving GroupsOrganize Problem-Solving Groups

Upgrade HousekeepingUpgrade Housekeeping

Upgrade QualityUpgrade Quality

Clarify Process FlowsClarify Process Flows

Revise Equipment and Process Revise Equipment and Process Technologies Technologies


JIT in Services (Examples)JIT in Services (Examples)

Level the Facility LoadLevel the Facility Load

Eliminate Unnecessary ActivitiesEliminate Unnecessary Activities

Reorganize Physical Reorganize Physical ConfigurationConfiguration

Introduce Demand-Pull Introduce Demand-Pull SchedulingScheduling

Develop Supplier Networks Develop Supplier Networks


JIT PeopleJIT People

Accept only 0 PPM quality Accept only 0 PPM quality rejection.rejection.

Are not passive witness.Are not passive witness. Keep the flow.Keep the flow. Continually suggest Continually suggest

improvement.improvement. Are interested in production.Are interested in production.



Know how to do their jobs.Know how to do their jobs. Know how to do other’s jobs.Know how to do other’s jobs. Can stop the line.Can stop the line. Assist their compatriots.Assist their compatriots. Predict and avoid problems.Predict and avoid problems. Measure their own output.Measure their own output.



Measure their own quality.Measure their own quality. Understand the product / Understand the product /

process.process. Call in resources as needed.Call in resources as needed. Are team players and team Are team players and team

leaders.leaders.


JIT in SubcontractingJIT in Subcontracting

LocationLocation VolumeVolume ClubbingClubbing QualityQuality ResponsivenessResponsiveness Shelf lifeShelf life Cycle TimeCycle Time Forecast AccuracyForecast Accuracy Movement Constraints.Movement Constraints.

JIT

Documents

Transcript of JIT