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The Toyota Production System (TPS) is a systematic way to pursue the twin goals of perfectly satisfying customer need and creating meaningful work for every member of an organization. TPS was born of the needs of the Toyota Motor Corporation after W.W. II to close a productivity gap with the U.S., operate with a severe capital shortage and sell to a small, diverse market. The outcomes of TPS deployment are superior product and service quality, short lead time, low cost and a safe working environment (physically, professionally and emotionally).
One way to understand TPS is through four organizing principles called the Rules-in-Use as defined through observation by two professors at the Harvard Business School, Steven Spear and Kent
Bowen1:
- All work activity shall be highly specified as to content, sequence, timing, location and expected outcome.*
- Every customer-supplier connection must be direct, and there must be an unambiguous yes-or-no way to send requests and receive responses.*
- The pathway for every product and service must be simple and direct, with no forks or loops.*
- Any improvement must be made in accordance with the scientific method, under the guidance of a teacher, at the appropriate level of the organization closest to the work.*
*All rules require that activities, connections, pathways and improvements have built-in tests to signal problems automatically.
These Rules-in-Use enable every member of an organization to design, do and improve work, lending robustness to operations as every worker can identify and solve problems in the course of work.
Conventional business views profit as that margin added to costs to arrive at a price. Toyota views profit differently. In TPS, the market ultimately determines price, and profit is viewed as the reward available by eliminating waste in the cost structure. Just-In-Time (JIT) production and Autonomation are the twin pillars of TPS' method of eliminating waste to meet customer needs and make work more meaningful.
JIT requires that production systems be configured to produce what is needed in the type and quantity required when it is needed. If immediate a response cannot be achieved, countermeasures in the form of stores, safety stocks (controlled inventory) and signal cards (kanbans) are deployed.
Autonomation means adding human intelligence to the automation of work. Autonomated machines, for example, stop when a defect is detected. The larger principle of Autonomation implies that a process is stopped by people or equipment to prevent a defect from proceeding to the next step. In this way problems are identified and solved rapidly when they are small and simple, rather than large and multi-variable.
In order for JIT and Autonomation to succeed, work must be highly stable. Some methods for stabilizing work include:
- Standardized Work
- Work balancing
- Flexible, cross-trained workers
- Takt time (the rhythm at which work must proceed to meet customer demand in the time available.)
- A signal to enable every worker to call for help from the place of work (Andon)
- Mistake-proofing work
- Continuous Flow
- The 5S process of ordering and cleaning a work
environment
- Total Productive Maintenance
- Visual Management of information and the place of
work
- Changeover time reduction
- Leveling customer demand.
Finally, TPS is founded on strong people values. A "pathway of assistance" is set up for everyone to provide for continuous learning and the rapid resolution of problems. TPS strives to provide a clear answer to workers' questions:
- What do I do next?
- How do I know how to do my work?
- Once I have done my work, how do I know it is correct?
- If I have a problem, how do I get help?
Every worker is viewed as having the right to perform meaningful work under the guidance of a teacher to meet customer needs.
The Toyota Production System is a system: its parts and organizing principles depend on each other to work. Thus TPS must be implemented as a system in order to function.
1Source: Steven Spear and H. Kent Bowen, Decoding the DNA of the Toyota Production System, Harvard Business Review, Sept.-Oct. 1999, p. 96
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