Kamban is a card or signboard (or any other authorizing
device) that is attached to specific parts in the
production line signifying the delivery of a given
quantity. The quantity authorized per individual kamban
is minimal, ideally one. The number of circulating or
available kamban for an item is determined by the demand
rate for the item and the time required to produce or
acquire more. This number generally is established and
remains unchanged unless demand or other circumstances
are altered dramatically; in this way inventory is kept
under control while production is forced to keep pace
with shipment volume.
A routine exception to this rule
is that managers and workers are continually exhorted to
improve their processes and thereby reduce the number of kamban required.
When fully implemented, kamban (the
plural is the same as the singular) operates according
to the following rules:
All production and movement of parts and material take
place only as required by a downstream operation, i.e.
all manufacturing and procurement are ultimately driven
by the requirements of final assembly or the equivalent.
Kamban have various formats and content as appropriate
for their usage; for example, a kamban for a vendor is
different than a kamban for an internal machining
operation.
