What are the 7 principles of TPS?
- Reduced Setup Times: All setup practices are wasteful because they add no value and they tie up labor and equipment. By organizing procedures, using carts, and training workers to do their own setups, Toyota managed to slash setup times from months to hours and sometimes even minutes.
- Small-Lot Production: Producing things in large batches results in huge setup costs, high capital cost of high-speed dedicated machinery, larger inventories, extended lead times, and larger defect costs. Because Toyota has found the way to make setups short and inexpensive, it became possible for them to economically produce a variety of things in small quantities.
- Employee Involvement and Empowerment: Toyota organized their workers by forming team and gave them the responsibility and training to do many specialized tasks. Teams are also given responsibility for housekeeping and minor equipment repair. Each team has a leader who also works as one of them on the line.
- Quality at the Source: To eliminate product defects, they must be discovered and corrected as soon as possible. Since workers are at the best position to discover a defect and to immediately fix it, they are assigned this responsibility. If a defect cannot be readily fixed, any worker can halt the entire line by pulling a cord (called Jidoka).
- Equipment Maintenance: Toyota operators are assigned primary responsibility for basic maintenance since they are in the best position to defect signs of malfunctions. Maintenance specialists diagnose and fix only complex problems, improve the performance of equipment, and train workers in maintenance.
- Pull Production: To reduce inventory holding costs and lead times, Toyota developed the pull production method wherein the quantity of work performed at each stage of the process is dictated solely by demand for materials from the immediate next stage. The Kamban scheme coordinates the flow of small containers of materials between stages. This is where the term Just-in-Time (JIT) originated.
- Supplier Involvement: Toyota treats its suppliers as partners, as integral elements of Toyota Production System (TPS). Suppliers are trained in ways to reduce setup times, inventories, defects, machine breakdowns etc., and take responsibility to deliver their best possible parts.