430 Glossary
things: a pull signal and a xed upper volume limit. A xed upper
volume limit means the operators must stop producing parts when-
ever they have not received their (pull signal) authorization to produce
more. Pull signals are sometimes called Kanbans (Duncan 1995).
push system: the antithesis of the pull system. Push systems allow produc-
tion to continue based on a predetermined schedule. Push systems
launch orders into the production system on a scheduled interval
and assume that they will come out the end of the process at the
end of the designated throughput times. Even the best closed-loop
push systems are much less responsive to in-process variation, and
therefore much less effective for controlling production and work-
in- ...