Nepedia
Back to Discover
Advanced Reader
💻

Lean manufacturing

technology Maturity 11-13 Next article →

Lean manufacturing is a sophisticated management system designed to optimize production. It operates on three core principles to ensure maximum efficiency. First, a company must produce only what is needed, exactly when it is needed. Second, it must correct abnormalities or errors as soon as they occur. Third, the system empowers workers to improve the production process themselves. The central goal of Lean is to eliminate all activities that do not add value for the customer. By removing these non-value-added steps, companies can increase productivity and total profit.

To understand how Lean works, one must look at its specific mechanisms. It builds upon just-in-time (JIT) manufacturing, which focuses on inventory strategy. In a JIT system, a factory receives goods only as they are required for production. This reduces inventory costs and prevents waste from unused supplies. Lean expands this idea by reducing cycle time, flow time, and throughput time. This means the entire system, including marketing and customer service, moves more quickly. However, this requires very accurate demand forecasting. Even minor delays in the supply chain can nullify the benefits of a Lean system.

The Toyota Production System (TPS) relies on two conceptual pillars: just-in-time and jidoka. Jidoka is often called "autonomation," or automation with a human touch. This principle involves designing equipment to detect abnormalities and stop automatically. This prevents defects from moving downstream to later stages of production. Jidoka can be mechanical, using sensors to halt a machine. It can also be human, where operators are empowered to stop the line. To help with this, companies use an andon system. An andon is a visual or auditory signal, like a button or cord, that alerts supervisors to a problem.

Engineers like Shigeo Shingo identified seven specific categories of waste to be eliminated. These include inventory, which is excess raw materials or finished goods. Overproduction is the act of making more than is currently needed. Over-processing involves working beyond the standard expected by the customer. Transportation refers to the unnecessary movement of people or goods. Excess motion involves unnecessary physical movement by workers. Waiting occurs during inactive periods in job queues. Finally, defects involve the cost of reworking errors. Some researchers also identify unused worker skills as a form of waste.

The history of Lean is a journey from early management theories to modern global standards. In 1911, Frederick Winslow Taylor documented manufacturing efficiencies in his book, "Principles of Scientific Management." Henry Ford applied similar ideas in the early 1900s, though these focused mostly on physical organization. Before World War II, W. Edwards Deming and Walter A. Shewhart developed formalized philosophies using statistical models. After the war, Deming assisted in Japan's reconstruction as a consultant for companies like Toyota and Mitsubishi.

W. Edwards Deming
W. Edwards Deming

Japanese manufacturers were highly receptive to these methods due to unique constraints.

Post-war Japan faced specific challenges that made Lean essential. The country lacked the cash to finance large-batch production methods. It also lacked the physical space to build massive factories filled with inventory. Furthermore, Japan had few natural resources to build products. These conditions forced manufacturers to build smaller factories. In these spaces, the only materials present were those currently being worked on. This kept inventory levels low and allowed for a quick turnaround of purchased resources. Taiichi Ohno and Shigeo Shingo later refined these ideas into the Toyota Production System.

Ohno transformed production by observing American supermarkets. He realized that work scheduling should be driven by actual sales rather than production targets. This created a "pull" system, or build-to-order, instead of a "push" system. News of these successes reached the West in 1977 through English-language articles. Adoption accelerated after a 1980 conference at Ford World Headquarters in Detroit. By the mid-1980s, major companies like Apple, Motorola, and General Electric had adopted JIT practices. The term "Lean" was officially coined by John Krafcik in 1988.

Lean manufacturing has shown significant, measurable results in real-world applications. At an Omark Industries plant in Mesabi, Minnesota, the results were quite dramatic. After implementing a zero-inventory system, the plant cut large-size drill inventory by 92%. Productivity increased by 30%, while scrap and rework dropped by 20%. Most importantly, the lead time from order to finished product fell from three weeks to just three days. This demonstrates how Lean connects resource management to rapid, high-quality output. Today, Lean remains a vital field for improving how the world creates goods.

745 words

Where will your curiosity go next?

Keep exploring at your chosen reading level.

🖼️ Images & Media (1)
File:W. Edwards Deming.jpg
W. Edwards Deming.jpg
More to explore

What is Nepedia?

A free, ad-free encyclopedia for children. Every article is written at five reading levels, so the same page works for a five-year-old and a fifteen-year-old — use the level switcher above to see this one change. No account needed to read.