What is lean manufacturing?
The methodology of the lean six sigma is to bring about the maximum result with less time in the inventory, space, people and money. The lean aims about speeding up the process and getting the right product at the first time. Here lean manufacturing is the systematical approach of identification and the elimination of waste through continuous improvement by the flow of products, which meets the demand of the customer.
The philosophy of lean manufacturing is derived from the “Toyota Production System”. Lean manufacturing is a generic process of management, for the production of goods through the removal of waste and implementing the flow. The operational strategy in lean manufacturing gives importance in the achievement of better production of goods that meet the customer’s satisfaction, through the process of shortest possible cycle time by eliminating waste and reducing incidental work. Lean manufacturing is a technique which helps in decreasing the time between the customer need and the shipment. It is designed in a way that there is a rapid improvement in the profit, gaining the customer satisfaction, reducing the production of time and sustaining the employee emotions. In general it is said that lean manufacturing is considered as a company’s “half human effort, the half manufacturing space, the half investment in tools and the half engineering hours for the development of a new product with in the half time scheduled”. It is clear that the benefits gained through the implementation of lean manufacturing is the lower costs, higher quality and shorter lead time for the production.
The characteristics of lean processes are:
-Repetitive order characteristics
-Just-in-time materials or pull scheduling
-Short cycle times
-Continuous flow work cells
-Collocated machines, equipment, tools and people
Lean manufacturing approaches:
Lean manufacturing is used under two approaches. The first approach is used for the identification and the continuous elimination of the waste. It is clear that as the waste is being eliminated, the quality of the product improves, while the production time and cost is reduced. The second approach to lean manufacturing, is focusing on improving the “flow” of the work. By the word flow means, the smoothness of the work. in the second approach the focus is given in the smoothening of the work, through the system and not the waste reduction. The second approach was promoted by Toyota.
The difference between the two approaches lies not on the attainment of the goal, but achieving the goal at the first time itself. In the second approach, the smooth flow of the work helps in exposing the defects or the quality problems which is there in the work already. This exposing of the defects leads to the reduction of the waste naturally.
Types of wastes:
The elimination of waste is the goal of lean manufacturing and Toyota defined that there are three types of waste like: “muda, muri and mura”.
MUDA: muda is process of activity that results wasteful or which does not add any value to the production of goods which meets the customer satisfaction. There are seven types of muda. They are as follows:
Overproduction: Production of goods beyond the demand
Transportation: Moving the products that is not required for the processing
Waiting: Wasting the time waiting for the next production step
Inventory: All the necessary steps like components, work-in-progress and finished products not being processed
Motion: Movement of the people or the equipments more than it is needed for the processing
Over Processing: The result of poor tool or product design creating activity
Defects: The efforts used in inspecting and fixing the defects.
MURI: The pushing of a person or a machine beyond its natural limits with in a work is referred as muri, which is another type of waste. all types of unreasonable works that the management is imposing towards the workers and the machines comes under this category. This is because of the poor management organization. Poor management organization such as making carry heavy weights, moving things around, dangerous tasks, even working faster than usual
MURA: This is the action which focus on the implementation and elimination of fluctuation at the scheduling or the operational levels. This includes the levels of quality and volume.