Kanban : Rules and Philosophy:

Seven rules control the operational environment of Kanban system. These rules are simple but any violation of them shall cause disturbance in the system, resulting in wastage of materials and labour. The Kanban rules are in agreement with Just-in-Time system principles. These rule are aimed at ignoring excess inventory on the manufacturing floor. These are following:

Rule 1 : Move the Kanban Only When the Lot it Represents is Consumed

This rule calls for the subsequent procedure to withdraw the necessary parts from the preceding procedure in the necessary quantities and at exact time needed. A subsequent process should send a Kanban to the preceding process asking for more parts only after the subsequent procedure has consumed all the parts that the Kanban was escorting.

Rule 2 : No Part Withdrawl Without a Kanban is Allowed

The movement of parts from a preceding process to a subsequent process is permitted only by the use of a Kanban. No preceding process may move parts without the authorization of a Kanban request.

Rule 3 : The Number of Parts Issued to Subsequent Process must be the Exact

Number Specified by the Kanban

The preceding procedure must not issue Kanbans with a partial count of parts. They should have the exact quantity specified by the Kanbans. Alternatively, if only a partial number of parts are available in the preceding process, a line shortage is formed. The Kanban should wait until the preceding process generates enough parts to meet the number requested by it.

Rule 4 : A Kanban Should Always be linked to the Physical Products

A Kanban is a traveling card, and it shall always travel alone from the subsequent procedure to the preceding process to request new parts. But once the worker associates the Kanbans to a new lot of parts, the card should travel with the lot until the last part is utilized. The Kanban should be attached to the lot in such a way that it is always visible to the workers.