One of the effective ways of increasing the profitability of any enterprise is through waste elimination. Processes can either add more value or massive wastes to the production of goods and services. The seven wastes of lean manufacturing came from Japan where there were referred to as “Muda.” The first step towards eliminating waste is understanding what waste is and the specific places where it exists in your processes. The wastes found in various manufacturing environments tend to be similar. Here are the seven wastes in lean manufacturing.
Overproduction refers to the process of manufacturing specific items before they are needed in the market. Overproduction is expensive since it hinders the uninterrupted flow of material and degrades the quality of products produced. Overproduction in industrial manufacturing is usually referred to as “Just-In-Case” manufacturing. This type of manufacturing will lead to significant storage costs, excessive lead times, and make it almost impossible to notice defects. The solution to this waste is stopping the production tap. You should only manufacture what can be shipped or sold immediately.
The waste of transportation usually refers to the movement of items between different processes. This will involve the use of a forklift truck or similar equipment to move products around the factory. Transportation is a waste occurring as a result of overproduction. Excessive movement of products around the factory will cause harm and can also lead to deterioration in the quality of the products. The equipment used to move the products around the factory lead to another production cost that adds no customer value.
3. Over Processing
Over processing is extra work that adds no significant value to the consumer or business. Over processing is a waste that takes the form of adding unnecessary features to a product that the customer doesn’t use but raises the cost of production. A good example of over processing would be maintaining paint finish more tightly than required or building a product that will last for five years when you know that the customer will replace it after two or three years.
4. Excess Motion
The waste of excess motion is related to wasted movement and is evident in all cases of walking, stretching, lifting, bending, and reaching. Some of these issues are also related to safety and health which is becoming a major concern in today’s world. Technically, jobs that require excessive movement need to be analyzed and re-engineered for significant improvement with the participation of the industrial workers.
5. Excessive Inventory
Excess inventory is a waste representing cash that is tied up in the form of material which is technically difficult to turn into liquid cash quickly. Inventory eats up much storage at the manufacturing plant since it has to be managed and stored. It can also become obsolete leading to more waste. The quality of any inventory can undergo deterioration over time especially perishable goods such as rubber seals or food.
The manufacturing waste of waiting hours occur whenever products aren’t moving or being processed. Waiting is perhaps the most common lean manufacturing waste of the seven. It is lost time due to poor flow of production process. Equipment breakdowns, part shortages, and bottlenecks can also lead to waiting wastes. Waiting can also frustrate the workers leading to reduced morale. The Goldratt’s theory of constraints states that every hour lost in a typical bottleneck is like an hour lost to the entire factory output which is impossible to recover.
Defects have a direct and substantial impact on the quality of products manufactured. Defects will lead to rescheduling, re-inspecting, and loss of capacity. The overall cost of defects is always a substantial percentage of the entire manufacturing cost. This waste can be reduced through continuous process improvement and employee involvement in the production process.