Implementing a kanban pull system
A kanban pull system replaces pushing material through production on a schedule with replenishing it only as downstream consumption signals demand. Signals — cards, bins or electronic triggers — authorise each upstream step to make only what the next step has used, capping inventory and exposing flow problems instead of burying them in stock.
What it is
Kanban is a method of controlling production by demand rather than forecast. Instead of each stage making as much as it can and pushing it forward, a stage produces only when a downstream signal tells it that stock has been consumed. Implementing it means sizing the buffers, designing the signals, and disciplining every stage to make nothing without a kanban authorising it.
Why it is done
Push scheduling based on forecasts overproduces, builds inventory and hides the real constraints in piles of stock. Pull with kanban limits work-in-progress to a deliberate level, so problems — a slow step, a quality issue, a breakdown — surface quickly instead of being masked by buffers. It reduces inventory and lead time while keeping flow stable and self-regulating.
How it is done
Demand and the variability of each step are analysed to size the buffers, because too little stock starves the line and too much defeats the purpose. Kanban signals are designed — physical cards or bins, or electronic equivalents — with rules that nothing is made or moved without one. The system is run, the number of kanbans is gradually reduced to tighten flow and expose hidden problems, and those problems are fixed rather than re-buffered as they appear.
- Analyse demand & variability
- Size buffers
- Design kanban signals
- Set pull rules
- Reduce kanbans gradually
- Fix exposed problems
What to watch for
Sizing buffers too small before the underlying variability is tamed starves the line and discredits the whole system. Letting people override the pull rules and produce ahead without a kanban quietly turns it back into a push system carrying the same excess stock.
Related practices
Reducing changeover time with SMED
Optimising clean-in-place (CIP)
Running a process capability study
Related topics
Kanban · Lean Manufacturing · Takt Time
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