An Introduction to Lean Manufacturing
Ronald Fite, Founder, Fite's Professional Services, LLC
Lean Manufacturing can be thought of as a systematic approach to reducing waste in the production process. In this sense, waste is anything (activities, processes, tools, materials, personnel) that does not add value to the product or service as viewed by the customer.
In the 1940s Taiichi Ohno and Shigeo Shingo improved upon previous manufacturing breakthroughs interchangeable parts, time and motion measurement, assembly lines-to create the Toyota Production System(TPS), the principles and practices of which eventually also became known as Just-in-Time (JIT) manufacturing.
This groundbreaking thinking catapulted Toyota into the global spotlight, and its processes became premier industry practices that everyone aspires to emulate. Because TPS pares manufacturing down to the bare essentials needed for high-quality production, the approach took on yet another telling name in the 1990s:Lean Manufacturing.
In an effort to better understand the true definition of waste, Lean divides the various types of waste into seven categories:
- Over processing
- Scrap or defects
Best thought of as symptoms of larger problems, the wastes are like the tips of icebergs. They indicate problems that are out of sight and that can run much deeper. Problems are compounded because, without TPS or Lean, manufacturers tend to treat symptoms only and rarely identify root causes. Original problems recur and new ones can even be created, because they just receive a quick fix and are not truly solved.
A typical example is a company that has excessive rework. Customers ultimately receive products but only at the expense of longer lead times, higher inventories, and greater costs to the company. It isn't until inventory levels are reduced that the focus shifts toward finding the root cause of excessive rework and scrap problems. In an effort to solve delivery issues, companies might create greater inventories than needed. Such inventories are like rivers that cover rocks hidden below the surface. As inventories (water levels) are reduced, many hidden problems unrecognized in the past become visible.
In a true Lean environment, inventory levels are reduced, hidden problems revealed, and solutions developed in a way that supports team concepts, collaboration, new ideas, and a common goal: satisfying the customer. This approach, and the results it produces, is one of the great differences between Henry Ford's breakthrough processes and Toyota's. Ford was very good at producing one specific type of automobile without variation. (He once famously said, customers could buy Ford cars in "any color so long as it's black.") Toyota's processes, on the other hand, allow quick changes that result in delivery of specifically what the customer wants.
Lean Manufacturing has inspired many new ways to eliminate waste. Some include tools such as SMED (single-minute exchange of die), cellular manufacturing, Kanban (a signaling system that facilitates quality improvement), and mistake-proofing, to name just a few. Lean Manufacturing has evolved so that it's now also referred to as Lean Thinking.
This different viewpoint has led many services companies to benefit from implementing Lean methods and eliminating waste. Many companies have tried, unsuccessfully, to duplicate the success of Toyota, even though they have even named their efforts after the recognized Toyota Production System. The companies that do benefit from Lean Manufacturing succeed in creating an environment that is totally supportive of the entire continuous improvement effort. They understand a core principle of Lean: Success is not simply using tools and strategies but using all assets of a company, especially its people.
© 2007 Ronald Fite. All rights reserved.