The Principles of Lean Manufacturing
To gain a competitive edge, many companies have adopted lean manufacturing (or lean thinking) as a keystone for success in today’s global market. Lean manufacturing has enabled businesses to increase production, reduce costs, improve quality, and increase profits by following five key principles: identify value, map the value stream, create flow, establish pull, and seek perfection.
Where Were Lean Manufacturing Principles Formed?
The lean manufacturing principles were formed in Japan. In an effort to improve sales and increase profit, Eiji Toyoda embarked on a journey to improve Toyota’s manufacturing processes. Inspired by his visit to the Ford facility in Michigan, he collaborated with Taiichi Ohno to develop a series of lean manufacturing tools. Collectively known as the Toyota Production System, these tools gained prominence in James Womack’s and Daniel Jones’ book, Lean Solutions, where the authors identified the five principles.
The Five Lean Manufacturing Principles
The five lean manufacturing principles are the foundation of Toyota’s success and can help businesses create products centered on what customers want.
The first lean principle, identifying value, is also the first step in the journey to become lean. This step requires businesses to define what customers value and how their products or services meet those values. In this case, value requires:
- Designing products to meet the needs of customers
- Removing features that do not specifically meet those needs
By designing products to meet specific needs, businesses will eliminate wasteful steps that may have been required for unwanted features. Design for Six Sigma (DFSS) is one method that can help businesses identify value. Using DFSS, companies can systematically define, measure, and analyze what their customers want. Companies can then design products tailored for their customers.
Map the Value Steam
The second lean manufacturing principle is mapping the value stream. A value stream is the complete life-cycle of a product, which includes the product’s design, the customers’ use of the product, and the disposal of the product.
This step requires companies to identify and map the product’s value stream. Lean tools like Value Stream Mapping (VSM) can be used to visually map out the entire product flow. Once the value stream is mapped, it will be easier to find and minimize steps that do not add value.
The third lean principle is creating flow. Efficient product flow requires items to move from production to shipping without interruption and can be achieved by strategically organizing the work floor. Every factor, from people and equipment to materials and shipping, must be taken into account to ensure products seamlessly move through the production process.
A well-organized work floor will result in reduced production time, inventory size, and material handling.
Closely related to creating flow, the fourth lean principle requires businesses to use a pull-based production system. Traditional production systems use a push system, which starts with purchasing supplies and proceeds by pushing material through the manufacturing process, even when there isn't an order. While push systems are easy to create, they often result in large inventories and a significant amount of work-in-progress (WIP).
A pull system, however, pulls a customer's order from the shipping department, which then prompts new items to be manufactured and signals that additional supplies need to be purchased. Lean manufacturing tools like Kanban can help businesses establish a pull system to control the flow of materials in a production system.
Using a pull system, businesses will:
- Increase output
- Maximize usable workspace
- Reduce inventories
- Eliminate overproduction and underproduction
- Eliminate errors caused by having too much WIP
The final lean manufacturing principle requires companies to seek perfection. While seeking perfection may seem straightforward, it is often one of the most difficult principles to successfully apply in the workplace. Seeking perfection requires companies to continuously improve their practices and often requires a shift in the workplace culture.
Kaizen, a philosophy of continuous improvement, can help businesses with this shift by creating a culture where workers seek perfection. Kaizen focuses on making small, incremental changes and requires every worker, from the corner office to the production floor, to help improve business practices.
Over time, Kaizen will result in increased efficiency, lower costs, greater productivity, and better quality products.
Solutions for Lean Manufacturing Principles
Our comprehensive best practice Guide to the 5S System provides the information you will need to start a lean program in your workplace. The guide breaks down how businesses can improve organization, standardization, and quality by systematically implementing the Five S’s: Sort, Set in Order, Shine, Standardize, and Sustain.