6 Top Lean Concepts and Tools

What is Lean manufacturing principle

Learn about Lean manufacturing concept and top 10 Lean tools used in manufacturing and other industries. The Lean principle is explained here in very simple words so that anyone new to Lean will understand it easily. All the lean tools are explained with practical examples and step by step approach to implement them.

A principle driven; tool based philosophy that focuses on eliminating waste so that all activities/steps add value from the customers perspective. Lean Thinking is all about continuous waste elimination & increasing Velocity!

Womack introduced the Lean production to western world in 90’s and he mentioned five guiding principles:

1. Specify value by product

2. Value stream for each product

3. Make value flow

4. Let customer pull value from the producer

5. Pursue perfection

1. Value : Value is defined by the customer. Customers in general do not define value based on where it is made and how it is made. Customers want their needs satisfied quickly, they want specific products, with specific capabilities, at a certain price. Specifying value is the first step in lean thinking, once value is defined it must be revisited again and again.

2. Value Stream/Value chain : The benefits of reducing waste can be magnified many times by concentrating on the set of activities that link a process together. Value streams can be constructed for each major product/process that an organization or plant produces. The value stream as used in Lean Manufacturing efforts goes into greater detail. It involves a single product which is analyzed for reduction of waste, reduction in cycle time or improvement in quality.

A value stream map is created to identify all the activities involved in the product. This value stream can include the various suppliers, production activities and the final customer. The activities are viewed in terms of the following criteria:

Value Add – It adds value as perceived by the customer

Value Add – It adds no value, but is required by the process

Non value Add (Muda) It adds no value, and can be eliminated

Muda and value Stream mapping are explained in detail under Lean Tools.

3. Value Flow : Traditional mass production is often accomplished by the batch technique within a plant. The objective is to produce many units of a specific part at a given time, in order to maintain the production efficiency of the machines and the overall efficiency of the departments. However, optimization of the individual operation unknowingly leads to sub optimization of the process as practiced by non-lean companies.

The lean effort requires the conversion of a batch process to a continuous flow process. In some cases, converting the batch process to a one-piece flow is ideal. Ideally in a continuous flow layout, the production steps for single flow, without WIP, are arranged in a sequence, straight line, U-shaped or in a cell. Inside this flow concept, the work of each station and operator must be performed with complete reliability. The quality level of each operation is very high, near perfect using a variety of defect elimination and detection techniques. These techniques include:

Poka-Yoke : To prevent defects from processing to the next step

Source inspection : To catch errors and to correct the process

Self check : Checks by the operator and to correct the process

Successive checks : Checks by the next process and to correct the process

“ The activities needed for production needed for production should be in a steady, continuous flow, with no wasted motions, no batches, no WIP, there should be flexibility to meet the present needs. The work of people, functions, departments and firms will require adjustments to the value stream to make it flow and to create value for the customer”.

4. Let customer pull value from the producer : Most mass production manufacturing firms are in the push production mode. Each operation produces as much as possible and sends it onto the next operation. The goal is to maximize machine efficiency with a maximum amount of in process inventory sitting around the plant.

Contrast the above, with the factory that is dependent on the pull of the market. The receipt of a customer order initiates activities. Each operation produces parts as needed through a signal from downstream. There is a minimal amount of WIP in the process stream. “ Instead of creating product in response to an estimated sales forecast, the plant manufactures product as the customer requires it. This is the Pull system in action.”

5. Pursue perfection : The customer is searching for a value-added product. Solving customer value problems, working the value system, converting to flow and making pull occur, all help eliminate muda (waste). As the process continues, more muda is removed from the process.

Perfection is achieved through:

1. Product teams working with the customer to find better ways to specify value. Enhance flow and achieve pull

2. Using technologies to eliminate muda

3. Developing new products

4. Using joint collaboration between the value stream partners (suppliers, sub contractors, distributors, customers, employees) to uncover more value and reduce muda

Benefits from Lean principle

Difference between Lean and Six Sigma