Friday, January 8, 2010

0302 - Kanban system درباره روش وسیستم کانبان

بسیاری از مطالب و توضیحات در رشته های فنی و مهندسی  همچنان به صورت ترجمه در اختیار علاقه مندان نمی باشد . امروزه استفاده از مطالب به روز و نو لازم و در اولویت قرار دارد به طوریکه اکثریت مهندس ها و افراد متخصص ناچارا از منابع اصلی به زبان علمی عموما انگلیسی استفاده می کنند برای ارائه مطالب نو ، پایان نامه و پروژه ، مقاله و تحقیق و تحصیل در درجه کارشناسی ارشد و دکترا در خارج از کشور و همچنین در داخل .. بنا به درخواست جمع کثیری از دانشجویان و متخصصین در کنار معرفی کتاب های زبان اصلی  مطالب و بخشهایی  از آنها را در این وبلاگ قرا می دهیم .. امید است که تا اندازه ای نیاز شما عزیزان بر آورده شود و سعی می کنیم در آینده ترجمه این مطالب را با موضوع ترجمه ی... در همین وبلاگ قرار دهیم . در صورت تمایل می توانید ترجمه آن یا در آدرس وبلاگ خود را برای ماارسال کنید تا با نام ومشخصات شما در این وبلاگ قرار داده شود.. مهندس درویشی کارشناسی فن آوری صنعتی .

Kanban system
Kanban (‘tag’) is a production planning and scheduling system based on a pull
instead of a push system. The goal of eliminating waste is also highlighted by
kanban. Kanban is a powerful force to reduce manpower and inventory, eliminate
defective products, and prevent the recurrence of breakdowns.
A kanban is a tool for managing and assuring just-in-time. Kanban is a
simple and direct form of communication, always located at the point where it
is needed. In most cases, a kanban is a small piece of paper inserted in a rectangular
vinyl envelop. On this piece of paper is written how many of what
part to pick up or which parts to assemble.
Kanban is a Japanese word that means ‘visual record’ and refers to a manufacturing
control system developed and used in Japan. The kanban, or card, as
it is generally referred to, is a mechanism by which a workstation signals the
need for more parts from the preceding station. The type of signal used for a
kanban is not important. Cards, coloured balls, lights and electronic systems,
have all been used as kanban signals. A unique feature that separates a true
kanban system from other card systems, such as a ‘travel card’ used by most
companies, is the incorporation of a ‘pull’ production system. Pull production
refers to a demand system whereby products are produced only on demand
from the using function.
Kanban always moves with the needed goods and so becomes a work order
for each process. In this way, a kanban can prevent overproduction, and prevent
large revenue losses in production.
Kanban, in essence, becomes the automatic nerve of the production line.
Based on this, production workers start work by themselves, and make their
own decisions concerning overtime. The kanbam system also makes it clear what
managers and supervisors must do. This unquestionably promotes improvement
in both work and equipment.
The main characteristic of a kanban system is its operating simplicity, and
its ability to reduce work-in-process. It is based on working to buffers, which
exist to protect the system from delays in production. Buffer size, however, is
a trade-off between protection and lead time. If buffer size is increased, the
protection increases, but so does the manufacturing lead time.
Once a kanban-activated workstation has filled its output buffer it is not
authorized to produce output again until the output buffer is depleted to its
reorder point. The workstation is said to be ‘blocked’.
200 Handbook of Production Management Methods
Kanban, requires a buffer of material for each possible part in front of each
resource. Therefore, for multi-product environments kanban requires substantial
inventory to achieve the necessary throughput.
Kanban is a tool for realizing just-in-time. For this tool to work well, the
production process must be managed to flow as much as possible. Other important
conditions are levelling production as much as possible and always working
in accordance with standard work methods.
Some kanban rules are as follows:
1. The earlier process produces items in the quantity and sequence indicated
by the kanban.
2. The later process picks up the number of items indicated by the kanban at
the earlier process.
3. No items are made or transported without a kanban.
4. Always attach a kanban to the goods.
5. Defective products are not sent to the subsequent process. The result is 100%
defect-free goods. This method identifies the process making the defectives.
6. Reducing the number of kanban increase their sensitivity. This reveals
existing problems and maintains inventory control.
The kanban system is most likely to be associated with just-in-time (JIT) systems
and the theory of constraints (TOC).
The success of kanban systems appears to depend heavily on complete implementation.
Even in cases where the implementation is complete, kanban systems
are unable to cope with product variety and demand fluctuation. It may be
that when kanban is used as part of a continuous improvement programme, as
with JIT philosophy, it is likely to produce increased benefits to the user.

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