Lean manufacturing also known as lean production, is the most effective technique for waste reduction and continuous improvement. The aim of any manufacturing company is customer satisfaction and this can be achieved by delivering a high-quality product at right time and at minimum cost. Every organization responds to changes for enhancing the value of the product to survive in the market. Therefore, value-added activities are necessary for continuous improvement and customer satisfaction, hence, lean manufacturing is becoming the core focus for better efficiency of the system and profit generation. Moreover, lean manufacturing produces an operational and cultural environment that is highly conducive to waste minimization. This study mainly focuses on the overview of lean manufacturing.
Toyota’s production system first introduced the idea of lean manufacturing in Japan. This concept was developed to maximize the utilization of resources by minimizing waste. There is a difference between lean manufacturing and traditional manufacturing. Traditional manufacturing focuses on inventory, whereas according to the lean concept inventory is considered waste.
Implementation of lean manufacturing in any type of industry has a significant impact on manufacturing processes. Today people have a different perspective on manufacturing processes. They understand that customers define the value of the product, and product value cannot be determined from the manufacturing point of view. The idea of lean manufacturing focuses on the removal of wastes from the organization.
According to the lean principle, waste is anything that doesn’t add value and the customer isn’t willing to pay for it. Through the successful implementation of lean elements, waste can be eliminated. There are the seven main types of waste mentioned in figure 1.
Overproduction is the manufacturing of a material or product that is of no use to the customer. Waiting is the extra time to process the product that adds no value to the customer. Transportation is the movement of products to several different locations. Inventory is the bulk stock within the manufacturing unit that is financially seen as the huge working capital. Over-processing is the extra step performed that doesn’t add value to the product. Motion is the movement of the people who operate the manufacturing facility is wasteful. Defects are errors during the process that require extra material, rework, or additional work.
The ultimate goal of lean manufacturing is the elimination of waste and production of good quality products by minimizing cost and in minimum time. To achieve this goal different lean manufacturing tools were developed to enhance the value of the product.
VARIOUS LEAN MANUFACTURING TOOLS
Correct selection of tools is effective in lean manufacturing. The involvement of people with a positive mindset is necessary to bring out change for a better working environment. The different manufacturing tools are shown in figure 2 and discussed briefly.
Value Stream Mapping (VSM)
Value stream mapping is a famous tool in lean manufacturing. It helps to identify the value-added and non-value-added activities contributing to the final product.
Kanban
Kanban is defined as the subsystem of the Lean manufacturing system. It was created to monitor inventory levels and the production and supply of components. This concept helps in reducing inventory and overhead costs.
Kaizen
Kaizen promotes continuous improvement as a result of continuous effort and employees’ involvement. Appreciate even the small improvement and encouragement to continue in the future.
5S
5S is a methodology for sorting, organizing, cleaning, standardizing, and sustaining a productive work environment. The 5S tool is used by various companies to make them clean and standardized.
DMAIC
Even though this methodology follows the essence of Six Sigma but sometimes it is also considered as an extension of the significance of Lean. DMAIC is a data-driven quality technique used to improve processes. DMAIC is an acronym that stands for Define, Measure, Analyze, Improve, and Control. It is a continuous five-step cycle.
Ishikawa Diagram
This tool is used to outline the different steps involved in the process. It determines where the quality issue arises and identifies the root cause of the problem.
FMEA
It is a proactive approach to identifying where the process might fail and to accessing the relative impact
Poka-yoke
Mistake proofing might be successive checking, contact type devices/ non-contact type devices to check the missing parts or a smart design that will accept the part in only one way.
History of Lean manufacturing
The concept of lean manufacturing was proposed by Toyota production systems (TPS) with the goal of reducing cost and improving quality by eliminating waste or non-value-adding activities. It involves reducing inventories and lead time and improving quality and productivity. According to Ohno, lean manufacturing reduces non-value-adding waste such as motion, inventory, transport, waiting, over-processing, overproduction, and defects.