When discussing Lean methodology, it’s impossible not to mention the Toyota Production System (TPS), a cornerstone in the world of manufacturing efficiency. TPS and Lean share many principles, making them interdependent in many ways. Understanding the nuances of TPS can offer valuable insights into the broader landscape of Lean methodology.
The basis of TPS was developed by Eiji Toyoda, Kiichiro Toyoda, and Taiichi Ohno. The system rests on two foundational pillars:
Initially implemented in Japan, Toyota later introduced TPS to the West. The adaptation incorporated continuous improvement and gave individuals a more autonomous role in the overall process, giving rise to Total-TPS (T-TPS).
Just in Time is all about efficiency—getting what you need, when you need it, and in the correct quantity. This principle extends to both internal and external customers, emphasizing the importance of process organization for efficient completion times. Key components of JIT include One Piece Flow, Pull production, and production according to Takt-time.
Taiichi Ohno, known as the inventor of the concept of the 8 wastes (muda), based his philosophy on a straightforward premise: “Every employee has to know what value he is adding for the customer. You stop with every other activity.” The first step to applying Lean, therefore, is identifying wastes in your processes.
The 8 Wastes: TIMWOODS
T = Transport
I = Inventory
M = Motion
W = Waiting
O = Overproduction
O = Overprocessing
D = Defects
S = Skills
Apart from muda, TPS and Lean also recognize mura (imbalance in the process) and muri (preventing tough work or overburdening), which will be more broadly explained in later phases.
Jidoka stands for built-in quality and focuses on error prevention. If a mistake occurs during production, work stops, and machines will switch off autonomously. Eiji Toyoda advocated for the ‘stop the line’ process, ensuring that errors are addressed immediately. Quality can’t be added later; it must be built into each step of the process. Jidoka’s philosophy emphasizes that the person responsible for any given step also bears the responsibility for its quality and problem-solving.
The Toyota Production System serves as a precursor and a parallel to Lean methodology, offering robust frameworks for efficiency, waste reduction, and quality assurance. Adopting the principles of TPS can significantly bolster your Lean initiatives, creating a culture of continuous improvement and excellence.