What is Lean Manufacturing?
The term “Lean” is a manufacturing concept that views the use of resources outside the main goal of creating a product for a customer to be "non-value-adding," and it seeks to identify wastes and eliminate them. This product or service is considered a “value” in the lean model.
Coined by quality engineer John Krafcik in his 1988 article, “Triumph of the Lean Production System,” lean relies on concept innovations that evolved during Taiichi Ohno’s creation of the Toyota Production System (TPS) and centers around providing value to customers, with less waste and ineffectual work. In fact, in its efforts to identify wasteful muda (Japanese term for waste), Toyota developed a list of the 7 wastes that specifically represent wasteful entities within their production process, and they work to eliminate or at least reduce any and all of the identified wastes.
Lean can be said to represent a state of mind, or ideologies that recognize and support any process improvement methodology and/or management system that helps companies reduce waste, improving the overall efficiency of the organization. These proven methods are used to optimize flow, increase efficient methods of production, decrease non-value-adding work, cut costs, and improve the quality of a product or service. Some tools of the Lean include: JIT, kaizen, value stream mapping, kanban, poka yoke, and 5S. As Lean methods continue to expand, helping a growing number of organizations improve, lean tools and products are also brought into play. One example or recommendation of a lean product would be vinyl floor tape which can be used to create defined safety zones.
At the beginning of the 1900s, Sakichi Toyoda incorporated the initial concepts of “autonomation,” or jidoka, into his production process. This autonomation was a device on his powered textile looms that would shut down if a thread broke—in order to prevent defects. This planted a seed for what was to come. In the 1930s, his company added another component, JIT, or Just In Time, an inventory production strategy that helped to reduce wasteful inventory excess.
Around the time that Toyoda and his son added automobile production to the company, Taiichi Ohno joined the production management, and, inspired by the writings of Henry Ford and after witnessing the stocking and production processes of supermarkets in the United States, Ohno realized the importance of producing only enough product to fill customer’s needs. Gone were the old days of ordering materials in the hopes of meeting sales goals—now, with the birth of the Toyota Production System, Ohno’s homage to Henry Ford’s production philosophies would provide high-quality products in pace with real-world customer demand.
With the JIT production process—aided using another of Ohno’s inventions, the kanban card inventory “pull” system, products could be built with relatively-low lead times, and with just enough supplies on-hand to fill sales. This proved efficient, reduced wastes, and allowed them to be competitive with such industrial juggernauts as the Ford Motor Company. This helped make Toyota grow in the next 50 years to become the largest automobile company in the world.
With a goal of increasing efficiency and reducing waste, lean concepts have evolved to include an understanding that these changes can come about easiest if done in smaller increments, known as kaizen. This idea of continuous improvement is important, because it is much easier to achieve things on the small-scale than to try and institute full-scale, company-wide changes and actually see improvement.
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Lean is not any one process, but a conglomeration of many tools, combined, and sometimes even conflicting with one another. It is a philosophy that relies on people to use their brains and common sense, for managers and assembly workers alike to be engaged and aware, and to try to make things better, one step at a time. If a waste is identified, defects may happen, time may be lost, things may not go smoothly, and all of that amounts to more waste. This decreases value to the customer, and efficiency is not attained. Finding what is working, and what is not, making sure that enough supplies are available, that workers are properly trained, and managers supervise and motivate workers, and products arrive to the customer in a timely way is the ultimate goal.
Using kanban cards to signal inventory shortages will help make sure the materials are where they should be and products will be out just in time (JIT), automatically reducing waste. Workers organizing their workplace and following the steps of 5S will ensure that work will be done efficiently, asking employees—from management down to assembly line workers—what can be suggested to improve the process (kaizen) may open new avenues to increased speed, quality, and means to cutting excess costs, and ensuring that levels of quality are sufficient to meet customers’ demands are all ways that lean manufacturing tools are implemented properly.
In all cases, lean manufacturing is only as strong as its weakest links, and the most important part of running a lean program is creating a culture where everyone has a stake in the future of the program. It is ultimately reliant on human workers to make it succeed.