The TPS house
TPS is usually drawn as a house. The roof is the goal: best quality, lowest cost, shortest lead time, best safety, high morale. The two pillars hold it up:
- Just-in-time (JIT): make only what is needed, when it is needed, in the amount needed, using pull systems, takt time and continuous flow.
- Jidoka: build quality in by giving machines and people the ability to detect an abnormality and stop, so defects are not passed on.
The foundation is stability: standardised work, heijunka (levelled production), total productive maintenance and visual management. At the centre are people and teams practising kaizen.
The principles behind it
- Eliminate the seven (later eight) wastes.
- Go and see (genchi genbutsu) before deciding.
- Stop and fix problems at the source rather than working around them.
- Standardise so that improvement has a baseline.
- Respect for people: develop the people who do the work and expect them to improve it.
TPS and lean
The term lean manufacturing was coined by Western researchers in the late 1980s to describe TPS. Lean kept the tools (5S, kanban, SMED, A3) and the principles, though many adopters took the tools without the management system underneath, which is the usual reason lean programmes fade.
The management system
What made TPS durable was not the tools but the routines: short daily meetings, leaders at the gemba, problems surfaced as they happen, standard work updated when an improvement holds. That daily management layer is what most organisations now rebuild when they revisit lean.