JIT 1

Just-In-Time (JIT)

JIT: an integrated set of activities designed to achieve high-volume production using

minimal inventories of raw materials, finished goods & work in process.

JIT …………………………………………AIPCS “a philosophy of manufacturing based on

planned elimination of all waste and on continuous improvement of productivity”.

“JIT objective “ To produce the ‘right part’ in the

‘right place’ at the ‘right time’ “

Introduction(Cont……….)“JIT “ also called

“lean manufacturing ““stockless production “

JIT targets to improve profits and return on investment by reducing

inventory levels (increasing the inventory turnover rate).

JIT Revolution Just in time revolution –Japan became the international

economic power . JIT –Term applied for only production scheduling and

inventory management where the products are produced only to meet actual demand and material for each stage of production are received and produced just

in time for the use of next stage of production and delivery to the customer .

jit : the entire way product were designed work was organized responsibility were assigned was transformed and constant striving for improvement and elimination

of waste was instilled.

An ideal production system and JIT•One product to produce•Demand is constant at rate one unit every t units of time•Customers and recourses are available at the production site•No defects in the material•No operational defects and no breakdown•Production process time is in multiple of purchases

Symptoms……

JIT and classical production systemJIT differ from the classical system in two ways1.Scheduling of production related to demand2.The size of production(Lot size)Classical System—Speculative demandDemand is folded back based upon the procurement or production lead time of each step in a production process to determine when production has to begin. To determine demand , production is initiated by scheduling the first production stage and the output is pushed throughout the production stage.(pushed production system)

Contd……

JIT SystemShort term is not based on demand forecast, rather it is based on replenishing stocks that are depleted by actual sales .specially when inventory f the product

drops to the certain level the final stage of the production process signals that more of the product is

needed soon . The final stage of the process then begin production as soon as possible . This requires that inventory of the input to the final stage to be

maintained . This process continue all the way back to the first production stage .

Contd….

• With the approach production of specific is entitled by the final stage of production in response to the actual or assured demand the production process is pulled through the system.

Charataristics ………..

PROCESS DESIGN ……………………… Small lot size ::

•“ideal lot size “—single unit •“small lot size enable JIT to operate efficiently”

Setup time reduction…………“in JIT ‘workers are trained to do their own setups’

“multipurpose equipment and setup procedures must be simple and standardized”.

“group technology are used to reduce setup costs and time”

Small lot size • Goal is to reduce lot sizes as much as possible.• Small lot size both in operation and delivery allow

JIT system to operate effectively.• Benefits In process inventory becomes less in JIT. it reduces the carrying costs, space requirements

and clutter in work spaces .Inspection and rework costs when problem with

quality occur (few items to inspect ).

Manufacturing cells ……………………Cells contains machine and tools Process similar

processing requirements .Cells are highly standardized and efficient production

centers.Benefits………………..

“Reduce changeover times ““High utilization of equipment”

“Ease of cross training operator “

Quality improvement……………………..“Finding and eliminating the cause of problem so they

do not continually crop up”.“JIT system minimize defects through use of

‘AUTOMATION’ ““”JIDOKA””-automatic detection of defects during

productionJidoka uses two machine ---

1.For detecting defects 2.To correct the cause of the defects

Inventory storage ……………………..“JIT system – designed to minimize inventory storage

““inventory storage is wastage “- JIT philosophy

Benefits1.Less carrying costs 2.Less space needed

3.Less rework if defects is needed 4.Less tendency to rely on buffer

Cont…………………Close vendor relationship—

“vendors should supply high quality goods with frequent delivery”

“poor quality of goods cause disruption in smooth flow in work”

“Goal – to identify a vendor as a producer of high quality goods”

PULL VERSUS PUSH SYSTEM::

“Push system”: when work is finished at a workstation ,the output is pushed to the next

workstation.“Pull system” : control of moving the work rests on the following operation. each workstation pulls the output from preceding work station as it is needed.

In pull system work moves on in response to demand from the next stage in process ,in push work moves

on as it is completed ,without regards to the next station readiness for the work.

JIT 18

Pull System

• Produce only when material is needed downstream…(cue from the user not the planning source)

• Pull materials sequentially through the factory.

• Orders placed at end item level.• Idle material is waste.• Need discipline…(Good practices reinforced

through training)

JIT 19

Push System

• Production authorized in anticipation of needs downstream…(cue is a work order from the planning system)

• Orders launched to meet due dates.• Keep machines & people busy.

KANBAN????A kanban is a card that is attached to a storage and

transport container. It identifies the part number and container capacity, along with other information, and is used to provide an easily understood, visual signal

that a specific activity is required

KANABAN …………………………………………..• Kanban scheduling systems are among the most

simple, effective and inexpensive means for manufacturing production and inventory control

• they reduce inventory, eliminate stockouts, displace massive computers and slash overhead.

• They improve both service and quality.• Kanban scheduling systems are useful when lot

sizes differ between process steps, processes are unbalanced or when distance introduces time lag or variability. These systems slightly de-couple the processes

Benefits of Kanban Systems

• Visual Production • Scheduling • Improved Inventory Control • Increased Inventory Turns • Lower Inventory Dollars • Improved Orderliness on the factory floor • Reduce wasted time looking for material

JIT 23

Setup Reduction

• Setup reduction is the process of reducing the time required to convert from production of the last good piece of unit A to the first good piece of unit B.

• use methods engineering/common sense.

• Ideal lot size = 1.

JIT 24

Setup Reduction (Cont.)

• Setup activities:– External: Operations performed while the

machine is running.– Internal: Operations performed after the machine

is stopped.

• Setup…responsibility of the operator.

Where JIT is feasible?JIT applies primarily to repetitive manufacturing

processes in which the same products and components are produced over and over again.

E.g... MacDonald.JIT focus on establishing the flow process by linking the workstation so that there is an even, balance of materials between the workstation and throughout

the entire production process.“work station are assembles like assembly line

balancing”

.Thanks