What is TPS?
TPS (Toyota Production System) is Toyota’s production system, which uses the two pillars of just-in-time and jidoka to achieve the best quality, the lowest cost and the shortest lead time by systematically eliminating waste. The system was largely built in the 1950s and 1960s by Taiichi Ohno, with the backing of Eiji Toyoda, and forms the foundation of LEAN manufacturing. TPS is more than a toolbox: it combines standardised work, continuous improvement and respect for people into a single way of working. For anyone designing OT systems, TPS matters because many of its principles now reappear in MES, SCADA and HMI screens on the shop floor.
🕰️ How did the Toyota Production System come about?
The roots of TPS predate the car factory and lie in the looms of the Toyoda family:
| Year / period | Event |
|---|---|
| 1896 | Sakichi Toyoda builds a loom that stops automatically when a weft thread breaks: the origin of jidoka |
| 1924 | The Type G automatic loom, which changes shuttles without stopping |
| 1930s | Kiichiro Toyoda, founder of Toyota Motor Corporation, formulates the idea of just-in-time and applies it in the new Koromo plant (1938) |
| 1950s-1960s | Taiichi Ohno develops the just-in-time framework, including kanban, and with Eiji Toyoda’s backing extends it across the plants |
| 1960s-1970s | TPS is extended to Toyota’s suppliers |
| 1978 | Ohno publishes his book on the Toyota Production System |
| 1984 | NUMMI, the Toyota and General Motors joint venture in California, makes TPS visible outside Japan |
| 1988-1990 | MIT researchers introduce the term lean production; The Machine That Changed the World appears in 1990 |
| 2001 | Toyota captures the wider philosophy in The Toyota Way, with continuous improvement and respect for people as its pillars |
TPS was therefore not designed in one go, but grew over decades of trial and improvement. That also explains why copying individual tools rarely delivers the same result.
🧱 What are the two pillars of TPS?
TPS is often drawn as a house: a foundation of stability, standardised work and improvement, two pillars and a roof carrying the goal (quality, cost, lead time).
| Pillar | Essence | Typical means |
|---|---|---|
| Just-in-time | Make only what is needed, when it is needed, in the amount needed | Pull, kanban, takt time, continuous flow, heijunka |
| Jidoka | Automation with a human touch: stop as soon as there is an abnormality, so defects do not flow onward | Automatic stop, andon, poka-yoke, root cause analysis |
According to Toyota, just-in-time rests on three principles: make only what is needed, do not let goods or information stall, and produce at the pace of sales. Each process pulls parts from the preceding process, which only replenishes what was taken. For a car with more than 30,000 parts, made by Toyota itself and by its suppliers, that demands tight synchronisation.
Jidoka means that a machine detects an abnormality itself and stops, and that an operator may stop the line with a pull cord. An andon board immediately shows where the problem is. As a result nobody has to watch a machine continuously, and a problem is solved at the source instead of afterwards at final inspection.
🧺 Which wastes does TPS fight?
TPS distinguishes three kinds of loss: muda (waste), mura (unevenness) and muri (overburden). Taiichi Ohno described seven forms of muda:
| Waste (muda) | Description | Example in a factory |
|---|---|---|
| Overproduction | Making more, or earlier, than needed | A line keeps running while there is no order |
| Waiting | People or machines standing idle | An operator waits for material or a release |
| Transport | Unnecessary movement of products | Pallets moved back and forth between halls |
| Overprocessing | More work or precision than the customer asks for | Double inspections, unnecessary finishing |
| Inventory | Too much raw material or work in progress | Buffers that hide problems |
| Motion | Unnecessary movement of people | Searching for tools, reaching too far |
| Defects | Products that have to be reworked or scrapped | Rejects after a wrong setting |
In Western LEAN practice an eighth waste was added later: the unused talent of employees. Ohno regarded overproduction as the worst waste, because it causes and hides all the others.
🔧 Which methods and tools belong to TPS?
| Method | Explanation | OT/IT support |
|---|---|---|
| Kanban | Signal card telling a preceding process that it may replenish | E-kanban via MES, ERP, barcode or RFID |
| Heijunka | Levelling production in volume and mix | Scheduling in MES/APS |
| Takt time | Production rhythm derived from customer demand | Comparison with the cycle time from the control system |
| Andon | Visual and audible signal on an abnormality | HMI, SCADA and alarm management |
| Poka-yoke | Error-proofing in design or process | Sensors, vision, interlocks in the PLC |
| Kaizen | Continuous improvement from the shop floor, following PDCA | Data from a historian |
| Standardised work | The documented best method as a basis for improvement | Digital work instructions |
| 5S | Order and tidiness in the workplace | Visual management |
Many of these terms later found their way into Lean, TPM and Six Sigma. Poka-yoke and quick changeover (SMED) are closely associated with Shigeo Shingo, who worked closely with Toyota.
🏭 How do you apply TPS in a modern factory?
A practical approach for a first production line looks like this:
- Determine the takt time - divide the available production time by customer demand. Example: two 8-hour shifts with 60 minutes of breaks in total give 900 minutes; with a demand of 900 units per day the takt time is 60 seconds.
- Measure the actual cycle times per station from PLC or MES data and find the bottleneck. A station with a cycle time above the takt time cannot meet demand.
- Stabilise the process with standardised work and TPM, so that breakdowns and variation do not disrupt flow. OEE shows where the losses are.
- Introduce pull with a limited number of kanban cards. A common rule of thumb is: number of cards = demand per time unit × replenishment lead time × (1 + safety factor) / quantity per container.
- Make abnormalities visible with andon and link every stop to a root cause analysis, for example with the 5 whys.
- Improve in short cycles following PDCA and record the new standard.
Toyota applies an important rule here: first perfect the work manually and remove muda, mura and muri, and only then automate. If you automate first, you automate the waste. Within Industry 4.0 this means that a digital twin or a Unified Namespace only adds value once the underlying process is stable and standardised.
🔐 What risks does just-in-time bring?
Minimal inventory makes a factory vulnerable to disruption in the supply chain and in IT links. On 1 March 2022 Toyota halted 28 production lines in all 14 of its Japanese plants for a day after a malware attack on supplier Kojima Industries; around 13,000 vehicles were not built. Anyone digitalising TPS principles should therefore include supply chain risk and business continuity in the design, and segment the OT systems that process kanban and call-off messages.
❓ Frequently asked questions
What is the difference between TPS and Lean?
TPS is Toyota’s concrete production system, built on just-in-time and jidoka. LEAN is the Western, general description of those principles, named by MIT researchers in 1988, so that other companies and sectors can apply them too. Lean adopts the tools of TPS but often lacks the corporate culture in which TPS is embedded at Toyota.
Who invented the Toyota Production System?
The Toyota Production System was mainly developed by Taiichi Ohno in the 1950s and 1960s, with the backing of Eiji Toyoda. The idea of jidoka goes back to Sakichi Toyoda’s looms and just-in-time to Kiichiro Toyoda in the 1930s. Shigeo Shingo contributed methods such as poka-yoke and SMED.
What does jidoka mean in TPS?
In TPS, jidoka is the principle that a machine or operator stops the process immediately when an abnormality occurs. This prevents a defect from flowing on to later steps and means the cause is tackled at once. Toyota describes jidoka as automation with a human touch.
Is TPS only suitable for the automotive industry?
No, TPS principles are also applied in electronics, food, logistics and healthcare, for example to shorten waiting times and standardise tasks. In the process industry pull works differently than in discrete manufacturing, but waste analysis, standardised work and kaizen are widely usable. The culture of continuous improvement matters more than the individual tools.
What role do OT systems play in TPS?
In TPS, OT systems provide the facts: cycle times, downtime and quality data from PLC, SCADA and MES. Andon is often implemented digitally through HMI screens and alarm management, and kanban as e-kanban in MES or ERP. Toyota stresses, however, that technology should support a good manual process rather than replace it.
How are TPS and TPM related?
TPS needs stable machines, because just-in-time with little inventory leaves no room for unexpected breakdowns. TPM provides that stability by making operators and maintenance jointly responsible for upkeep. Toyota supplier Nippondenso was the first company to introduce TPM plant-wide.
📌 In summary
TPS is Toyota’s production system, grown from Sakichi Toyoda’s looms and developed by Taiichi Ohno. It rests on just-in-time and jidoka, fights muda, mura and muri, and uses methods such as kanban, andon, heijunka and kaizen. Modern OT and IT systems make those principles measurable, but only on a stable and standardised process.
TPS is Toyota’s original production system and the basis for LEAN: it revolves around quality, flow, continuous improvement and respect for people.