JIT AND LEAN PRODUCTION
SYSTEM
BY
AMAR P. NARKHEDE
INTRODUCTION
Just in Time production logic evolved in Japan at Toyota later
extended to other companies in Japan and other countries.
Lean production is an integrated set of activities designed to
achieve high volume production using minimal inventories of
raw materials, work in progress and finished goods. Parts
arrive t the next work station Just in Time is also based on the
logic that nothing will be produced until it is needed. Need is
created by actual demand for the product.
JIT is the philosophy of operations management that seeks to
eliminate waste in all aspects of a firm’s production activities
Human relations, vendor relations, technology and
management of materials and inventories. Little inventories
focuses more narrowly on scheduling good inventories and
providing services resources where and when needed
THE TOYOTA PRODUCTION SYSTEM
The Toyota production system was developed to
improve quality and productivity and is directed by
two philosophies that are central to the Japanese
culture Elimination of waste and Respect for People
ELIMINATION OF WASTE:
Waste as defined by Toyota’s President Fujio Cho as
“Anything other than the minimum amount of
equipment, materials, parts and workers (working
time) which are absolutely essential to production”
SEVEN PROMINENT TYPES OF WASTE
• Waste from overproduction
• Waste of waiting time
• Transportation waste
• Waste of processing itself
• Waste of stocks
• Waste of motion
• Waste of making defective parts
This definition of JIT leaves no room for surplus or safety
stock. No safety stock are allowed because if you cannot
use it now, you do not need to make it now that would be
waste. Hidden inventory in storage areas, transit system,
carousels and conveyors is key target for inventory
reduction
SEVEN ELEMENTS THAT ADDRESS
ELIMINATION OF WASTE ARE
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Focused factory network
Group technology
Quality at the source
JIT production
Uniform plant loading
Kanban production control system
Minimized set up time
TECHNIQUES OF JIT
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Set up time reduction
Autonomous or modular cells
JIT layout
The pull system
Buffer stock removal
Continuous improvement
Total productive maintenance
Quality at source
Just in time purchasing
Employee improvement
THE KANBAN SYSTEM (THE PULL SYSTEM)
Kanban signals are required when
a. Assembly work, sub assembly work and manufacture of
parts is carried out at different locations and it is
impractical to move product one at time over long
distance
b. Set up time on the feeding operations is higher than
receiving operation
c. On or more machines are common to various work cells
and need to be linked to the cells with Kanban signals.
Linking the common machines an integral part of each
work cell on account of frequent signals from the cell as
to what to produce and when
d. There are bottlenecks or quality or capacity problems
which do not allow smooth flow
WHAT IS KANBAN SYSTEM
The working of Kanban system can be compared to
supermarket shelf which is continuously monitored
and refilled as customers help themselves. At the
supermarket, the customers pick up quantities of
goods they need. At the periodic intervals the
employee checks up to see what customers have
taken and what he puts back what has been taken.
Quantities picked up by the customers are the
quantities put on the shelves by the employee. The
Kanban system performs the same activity
Kanban is the Japanese word for a Card
KANBAN SIGNALS MAY BE ONE OF THE
FOLLOWING
• A card on which is written the part number, size of the container,
number of pieces to beheld by the container, and number of this
cards in the system
• Metal plates affixed to the container that are useful in an oily
environment and display the same kin of information as on the card
• Containers themselves
• Computer to computer Kanban system
Two types of Kanban system exist: single card Kanban system and
double card Kanban system. In a double card system, two cards are
used: a Withdrawal Kanban(C-Kanban) and production Kanban(PKanban). A withdrawal Kanban specifies the kind and the quantity
which the subsequent process should withdraw from the preceding
process while a production Kanban specifies the kind and the
quantity of the product which preceding process must produce
The contents of Kanban are:
a. Part name
b. Part number
c. Kanban number
d. Work station(from)
e. Work station(to)
f. Quantity
g. Container number(or Box)