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Just in Time ( J. I. T. )

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Just in Time PhilosophySalient features

The notion of waste in any operating system

JIT as a philosophy of elimination of waste As a deliberate and a systematic attempt On a continuous basis

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Just In Time Manufacturing Water Flow Analogy

Unrealistic Variable Defective Poorschedules Lack Processing Material Quality

of Timestraining

Machine Inadequate BottleneckBreakdown Information

Behavioural/Managerial constraints

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JIT PhilosophyCore Logic

Lot sizereductions

JITProductions

Scrap/qualitycontrol

Smootheroutput rates

Ideas forcutting

lot sizes

Ideas forimproving

JIT delivery

Ideas forcontrolling

defects

Fast feedbackon defects

Reduced bufferinventories

Heightenedawareness of

problems & causes

Lessinventory

High qualityFinished goods

Lessmaterial waste

Fewer rework

Less indirect costs

Deliberate withdrawalof buffer inventories

Less material, labour, indirect costs & better qualityLess material, labour, indirect costs & better quality

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JIT Philosophy Overall Impact

J IT Logic J IT Overall Impact Withdraw buffer “deliberately” Faster feedback on Quality Thereby expose hidden

problems in the system Quality Improvement

Identify solutions to the problems, implement and attain smooth production rates

Tightly linking preceding and subsequent processes

Repeat the above steps Increased responsibility effects

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JIT ManufacturingBasic Elements

Manufacturing system should conform to a flow process

Total Quality Management to be deployed Standard Containers Constantly eliminate waste

Setup time reduction – Lot size reduction Inventory reduction – Removing Kanbans Quality improvement – Small group improvements Defect free supplies – Supplier collaborations

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PUSH Scheduling

INVENTORIESQuantityDriven Measurements

Push

UtilisationInternal Focus

High Fixed Costs

Long LeadTimes

HighDemandForecast

INVENTORIESQuantityDriven Measurements

Push

UtilisationInternal Focus

High Fixed Costs

Long LeadTimes

HighDemandForecast

QuantityDriven Measurements

PushPush

UtilisationInternal Focus

High Fixed Costs

Long LeadTimes

HighDemandForecast

Forecast drives production

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PULL Scheduling

Customer Order

Finished Goods

Flexibility

Profit BasedMeasurement

PULL

External Focus

Faster Response

Factory

LowDemand

Customer triggers production

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PUSH – PULLImpact on the system

I ssues to Consider Push Scheduling Pull Scheduling Responsibility to monitor

Scheduler/system People in mfg.

Flow control I f all standards are met Always

Signal to build Schedule/system Visible - from customer

Inventory No limit – higher Limits – lower

Problems Can be hidden Exposed - creates urgency

Communication between Operations

By chance – operations work on their orders

By necessity

React time: Changes/problems

Through the system - rescheduling required

Immediate - on-line and visible

Visible indication of problem

Inventory Production Stops

Shop floor control System, transactions, paper work

Automatic, Visible & Simple

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Kanban as Planning ToolTerminologies

Preceding & Succeeding Processes In-bound & Outbound Buffers Design of Kanban System

Types of Kanbans Production Order Kanban (P-Kanban)

Standard Containers

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Just in Time Manufacturing

JIT systems have an unambiguous definition of what constitutes waste in the system.

The philosophy of Just in Time system is one of continuous waste elimination.

Contrary to the traditional thinking, the inventory in a JIT system is deliberately removed to expose hidden problems.

These problems are solved resulting in fewer inventory and waste in the system and greater productivity.

Implementation of JIT requires that the manufacturing architecture is converted into a chain of internal customers.

Lot size reduction and use of standard containers are other elements of a JIT system.

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Just in Time Manufacturing

Production Planning and control in JIT systems is achieved through the use of Kanban

Kanban enables waste elimination from the system by preventing overproduction and exposing problems in processes.

JIT systems utilise a Pull type scheduling Pull type scheduling are very effective in

providing visible control of the processes and bringing the problems to the surface rapidly.

The number of Kanbans required is a function of production and conveyance lead time, size of the standard container and the demand rate.

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Just in Time Manufacturing Kaizen

‘Kai’ in the Japanese means change, while ’zen’ means good (for the better),so that kaizen means ‘improvement’.

Kaizen in Japanese means Continuous Improvement in every sphere of Activity.

Kaizen is a sub-system of JIT. The management encourages suggestions or

Kaizens from employees regarding possible improvements in their respective work areas. The employees are rewarded for giving a large number of suggestions. These rewards are more of recognitions , such as “Kaizen Man of the Month” titles and certificates or small gifts, rather than monetary worth.

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Just in Time Manufacturing Andon

For error prevention and fault-finding, the operators must notify supervisors and management when a problem affects within the factory. To enable this, JIT uses a portable andon system. The andon in the Japanese means an ambulance-style flashing light with a complementary siren. The operator puts the andon on whenever he needs to draw the management’s attention, highlighting the importance of his problems. By reacting to his call instantly, the management ensures that customers are protected against receiving defective products.

The andon system is not effective until most

problems are solved.

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Just in Time Manufacturing Fixed Location Storage

JIT is successful only when there should be a fixed location for all components, parts, tools and equipments. The handling of parts and tools is minimised by properly locating in the assembly area and in stores.

Fixed locations assist in knowing the exact location of parts and the number of parts available for assembly. This ease of access increases productivity and reduces damages to components. The tools and equipments that are common to all workers should be brought back to their locations immediately after a worker finishes his work so that other workers may use them these whenever required.