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JUST IN TIME
MANUFACTURING PHILOSOPHY
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AGENDA
Introduction
Objectives of JIT
Goals for achieving JIT Key elements of JIT
Key elements to achieve JIT
Other elements of successful JIT
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INTRODUCTION
JIT is a philosophy of manufacturing
based on planned elimination of all wastes and
continuous improvement of productivity. Theideal just-in-time production system produces
and delivers exactly the required number of
each component to the downstream operation
in the manufacturing sequence just at the timewhen that component is needed.
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OBJECTIVES OF JIT
The main objective of JIT is to eliminate thefollowing wastes,
Waste of over production
Waste of transportation Waste of stocks
Waste of making defective products
Waste of waiting
Waste of processing
Waste of motion
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GOALS FOR ACHIEVING JIT
Zero defects
Zero inventories
Zero setup time Zero handling
Zero break downs
Zero lead time
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GOALS FOR ACHIEVING JIT
Reduce lot sizes
Preventive maintenance
Flexible work force Require supply quality assurance
Small lot conveyance
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KEY ELEMENTS TO ACHIEVE JIT
GOALS
PULL SYSTEM PRODUCTION CONTROL
In this system, the order to make and
deliver parts at each workstation comes from
the down stream station that uses those parts.
When the supply of parts at a given
workstation is about to be exhausted, that
station orders the upstream station to produce
the parts and fill again the supply
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KANBAN PRODUCTION CONTROL
SYSTEM
A kanban or pull production control system uses simple,
visual signals to control the movement of materials between work
centers as well as the production of new materials to replenish
those sent downstream to the next work center. Originally, the
name kanban (translated as signboard or visible record)referred to a Japanese shop sign that communicated the type of
product sold at the shop through the visual image on the sign (for
example, using circles of various colors to indicate a shop that
sells paint). As implemented in the Toyota Production System, 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.
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KANBAN PRODUCTION CONTROL
SYSTEM
In Toyotas dual-card kanban system,
there are two main types of kanban:
1. Production Kanban: signals the need to
produce more parts
2. Withdrawal Kanban (also called a "move"
or a "conveyance kanban): signals the needto withdraw parts from one work center and
deliver them to the next work center.
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KANBAN PRODUCTION CONTROL
SYSTEM
Dual-card Kanban Rules:
No parts are made unless there is a production kanban to
authorize production. If no production kanban are in the inbox at a work center, the process remains idle, and
workers perform other assigned activities. This rule
enforces the pull nature of the process control.
There is exactly one kanban per container.
Containers for each specific part are standardized, andthey are always filled with the same (ideally, small)
quantity. (Think of an egg carton, always filled with exactly
one dozen eggs.)
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KANBAN PRODUCTION CONTROL
SYSTEM
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KANBAN PRODUCTION CONTROL
SYSTEM
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KANBAN PRODUCTION CONTROL
SYSTEM
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KEY ELEMENTS TO ACHIEVE JIT
GOALS
HIGH QUALITY
JIT systems eliminate all defects,
which eliminates the scrap and reworkthat help to provide a smooth flow of
materials through the plant. The quality
is built into the process and is controlled
by workers acting as their own qualityinspectors.
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KEY ELEMENTS TO ACIEVE JIT
GOALS
SMALL BATCH SIZE AND REDUCED
SETUP TIME
Batch size and setup time must beminimized to minimize WIP inventories.
Reduced setup time permit smaller
batches and lower WIP levels. Setup
time may be reduced by the followingapproaches.
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KEY ELEMENTS TO ACIEVE JIT
GOALS
Design the setup tooling and plan the
setup method to permit changeover
procedure as much as possible.
Use time and motion study to reduce the
setup procedure to the fewest possible.
Eliminate or minimize adjustments in the
setup
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KEY ELEMENTS TO ACHIEVE JIT
GOALS
Use quick acting clamping devices
instead of bolts and nuts.
Use group technology and cellularmanufacturing so that similar part styles
are produced on the same equipment.
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OTHER REQUIREMENTS FOR
SUCCESSFUL JIT PRODUCTION
Stable production schedules
On-time delivery
Defect free components and materials Reliable production equipment
A work force that is capable, comitted
and co-operativeA dependable supplier base
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