Lean Manufacturing, in simple terms, is a practice that focuses on eliminating waste while maximizing productivity. One of the main goals is to identify what adds value and to remove anything that doesn’t add value. It was inspired by Taiichi Ohno and Eiji Toyoda, two individuals who worked to organize manufacturing and logistics for Toyota in Japan between 1948 and 1975. Their principles became known as the Toyota Production System (TPS). TPS helped to eliminate waste and propel Toyota into profitability and worldwide prominence.
The 5 Key Principles of Lean Manufacturing
The 5 principles of Lean Manufacturing were first mentioned by James P. Womack and Daniel T. Jones in their 1996 book Lean Thinking. Lean Thinking is a revolutionary way of approaching manufacturing. James and Daniel developed the 5 principles while studying the Toyota Production System.
The customer determines the need for a specific product. Therefore, identifying value is something that the customers determine, not the manufacturer.
Map The Value Stream
The next step after identifying the value (end goal) is to map the steps and processes that need to take place to reach that goal. The purpose is to identify steps that do not create value and to eliminate them. This eye-opening experience helps to map all the processes involved in turning raw materials into finished goods.
Ensure that all remaining production flows as smoothly as possible. This means eliminating delays, interruptions, and bottlenecks to ensure that the remaining value-creating steps flow uninterrupted.
Customers can “pull” the product as needed only when manufacturing flow has been improved. Often this process reduces lead times from months to weeks. This enables manufacturers to reduce inventory, eliminating costs for the manufacturer and the end-user/customer.
Lean manufacturing is not simply to complete steps 1-4 but to make them a part of the corporate culture. Therefore, every employee throughout the manufacturing process should be constantly looking to remove waste, improve flow, and mapping the value stream.
Types of Waste
Mura is a Japanese term that means “unevenness in operations.” For instance, inconsistencies or fluctuations in workflows create waste.
Muri is the Japanese term for the “overburdening of people and equipment.” This can include employee burnout due to stress. It can also refer to the breakdown of factory machines. Running production for too long or overloading machines causes burnout.
Muda is the Japanese term for “waste.” According to the Toyota Production System, there are 8 wastes that manufacturers should work to eliminate.
Defects – Any defective parts caused by either poor quality inputs or user error.
Overproduction – When the manufacturer produces too much product irrespective of demand or capacity. Overproduction increases costs for the customer and end-user.
Waiting – When production has to stop because a part of the workflow is overwhelmed, there’s a shortage of material, something has broken, or something needs managerial approval.
Not Utilizing Talent – Human talent is often under-utilized or misappropriated.
Transportation – Excess transportation between docks and warehouses can lead to increased costs and wasted time. Reduce potential waste with better process flow and layout.
Inventory Excess – An excess in inventory is caused when the supply surpasses demand.
Motion Waste – Any excess movement that doesn’t add value, either done by employees or machines.
Excess Processing – Any unnecessary steps or redundancies.
“Waste is anything other than the minimum amount of equipment, materials, parts, and working time which is absolutely essential to add value to the product or service.” – Ohno Taiicho
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