kanban in jit

7/29/2019 Kanban in Jit

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JIT (Just In Time)

JIT manufacturing is a philosophy ofmanufacturing based on plannedelimination of waste & continuousimprovement of productivity.

Just in time is a pull system ofproduction, so actual orders provide asignal for when a product should be

manufactured. Demand-pull enables afirm to produce only what is required, inthe correct quantity and at the correcttime.


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Advantages of JIT

1. Lower stock holding means a reduction in storage space whichsaves rent and insurance costs

2. As stock is only obtained when it is needed, less working capital istied up in stock

3. There is less likelihood of stock perishing, becoming obsolete orout of date

4. Avoids the build-up of unsold finished product that can occurwith sudden changes in demand

5. Less time is spent on checking and re-working the product ofothers as the emphasis is on getting the work right first time

Disadvantages of JIT

1. Production is very reliant on suppliers and if stock is notdelivered on time, the whole production schedule can be delayed

2. There is no spare finished product available to meet unexpected

orders, because all product is made to meet actual orders however, JIT is a very responsive method of production


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JIT elements1.

Product design element2. Process design element

3. Personnel/organizational elements4. Manufacturing planning and controlThree elements of product design are key to JIT systems:1. Standard parts

2. Modular design3. Quality

Personnel Organizational Elements-1. Workers as assets2. Cross-trained workers3. Continuous improvement4. Cost accounting

5. Leadership/project management


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Process Design element-1. Small lot sizes2. Setup time reduction3. Manufacturing cells

4. Limited work in process5. Quality improvement6. Production flexibility

7. Little inventory storage

Manufacturing Planning and ControlFive elements of manufacturing planning and control are

particularly important for JIT systems:

1. Level loading

2. Pull systems3. Visual systems4. Close vendor relationships

5. Reduced transaction processing


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Kanban

Kanban is the J apanese word for card

The card is an authorization for the nextcontainer of material to be produced

A sequence of kanbanspulls material throughthe process

Many different sorts ofsignals are used, butthe system is still calleda kanban


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Kanban

1. User removes astandard sizedcontainer

2. Signal is seen bythe producingdepartment asauthorization toreplenish

Part numbers

mark location

Signal markeron boxes

Figure 16.8


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Kanban

Figure 16.9

Workcell

RawMaterialSupplier

Kanban

PurchasedParts

Supplier

Sub-assembly

Ship

Kanban

Kanban

Kanban

Kanban

Finishedgoods

Customerorder

Finalassembly

Kanban


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More Kanban

When the producer and user are not invisual contact, a card can be used

When the producer and user are in visual

contact, a light or flag or empty spot onthe floor may be adequate

Since severalcomponents may

be required,several differentkanban techniquesmay be employed


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More Kanban

Usually each card controls a specificquantity or parts

Multiple card systems may be used ifthere are several components ordifferent lot sizes

In an MRP system, the schedule can

be thought of as a build authorizationand the kanban a type of pull systemthat initiates actual production


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The Number of Kanban Cards

or Containers Need to know the lead time needed to

produce a container of parts

Need to know the amount of safetystock needed

Number of kanbans(containers)

Demand during Safety

lead time + stockSize of container

=


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Number of Kanbans Example

Daily demand = 500 cakes

Production lead time = 2 days(Wait time +Material handling time +Processing time)

Safety stock = 1/2 day

Container size = 250 cakes

Demand during lead time = 2 days x 500 cakes = 1,000

Number of kanbans = = 51,000 + 250

250


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Advantages of Kanban

Allow only limited amount of faulty ordelayed material

Problems are immediately evident Puts downward pressure on bad

aspects of inventory

Standardized containers reduceweight, disposal costs, wasted space,and labor

kanban in jit

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