Lean Manufacturing is a unique perspective on successful manufacturing that has had a huge impact on the 20th and 21st century. What you’ll learn is that lean practitioners are focused on creating more value for your customers with fewer resources.
We will review the History of Lean, and the 5 Principles of the Lean Production System.
The history of lean starts with Henry Ford but really the credit to today’s lean tools and techniques goes to Toyota and it’s leaders.
Many of the core tools within Lean are used to improve the value creating processes to provide value while removing non-value adding activities (waste).
History of Lean and the 5 Core Principles of Lean
Okay, let’s jump into Lean Manufacturing with a brief history of lean, and the 5 core principles of Lean.
Brief History of Lean
The Lean Production System was popularized in 1990 by The Machine That Changed the World where MIT Researchers Jim Womack, Dan Jones and Dan Roos published their groundbreaking research into the successful practices being used at Toyota that was leading to massive success for the Japanese automaker.
In this research, Womack and team highlighted the unique approach of the Toyota Production System to achieve astonishing levels of success in the automotive industry, far outpacing the competition(GM, Ford, etc).
While the term LEAN was new to the world, the principles of lean were not new.
In fact, lean manufacturing began in the early 1900’s with Henry Ford and the techniques that were pioneered at the Highland Park, Michigan Plant where the Model T was produced.
Here, Henry Ford introduced the idea of a flowing production process with the moving assembly line, and the successful usage of interchangeable parts with standard work to define the entire production process.
After World War II, Toyota engineers Kiichiro Toyoda and Taiichi Ohno came to the U.S. to tour the U.S. auto factors to learn from Henry Ford.
Ohno and his team created many of the lean tools discussed here, including the 7 deadly wastes, Kanban systems and others which will be discussed below. Ohno took many of Fords original concepts (Pull, Flow, and JIT Inventory), and combined them with the wisdom of other Quality Guru’s like W. Edwards Deming to create what is known today as the “Toyota Way” or as it’s known in Toyota as the Toyota Production System.
The Toyota Way, published in 2001 and authored by Jeffery Liker was another major contributor to the lean world as it again highlighted the core concepts within Toyota and the Toyota Production System.
This in-depth study of Toyota highlighted the two core principles at Toyota: Continuous Improvement and Respect for People.
The other guiding principle that needs to be discussed is Respect for People. An organization cannot fully embrace lean without a deep respect for people.
This includes respect for a company’s customers, their employees and society as a whole. Fundamentally, lean is a “people first” approach to manufacturing.
It is people who drive continuous improvement, and it is people who own and execute the tools within lean. Without a deep respect for people, lean simply falls apart.
The 5 Core Principles of Lean
Womack and Jones expanded on The Machine That Changed the World with their 1996 book Lean Thinking where they created the 5 Core Principles of Lean Production:
- Identify Value
- Map the Value Stream
- Create Flow
- Establish Pull
- Seek Perfection
Let’s review each of these 5 core principles now, as they truly lay the foundation for many of the tools below.
Core Principle #1 – Value
The first core principle of Lean is to identify the value for the customer.
Value is inherently defined by the customer. A feature or characteristic of your product is not valuable unless the customer is willing to pay for it.
Therefore, the first step in lean thinking is to define value in the eyes of the customer.
The price of your product is based on the value you provide and what the customer is willing to pay. This ultimately determines the cost you can charge for your product. Organizations can then focus on eliminating waste to improve their profit margins.
Understanding what your customer finds valuable allows you to identify and eliminate waste in your product or process.
Core Principle #2 – The Value Stream
Once you understand the value associated with your product, process or service, you must then work to understand the value stream.
The Value Stream is the sum total of the entire lifecycle of your product from raw material all the way to final consumption and disposal by the customer.
Focusing on the entire Value stream ensures that you are able to achieve maximum value and eliminate waste. This big picture perspective ensures that every step in the process is examined for waste.
Below we will discuss a tool called the Value Stream Map that accomplishes this very task.
Core Principle #3 – Flow
The 3rd core principle of Lean is that value should flow through the value stream without delay or interruption.
Flow is achieved when lean practitioners are able to sync all steps in the production process in pursuit of a JIT (Just In Time) manufacturing.
Achieving a smooth, consistent flow is the key driver of many Lean tools including Takt Time, SMED, Kanban and JIT.
Core Principle #4 – Pull
The 4th core principle of lean is that value should be pulled through the value stream at the demand of the customer.
Building product before the customer demands it (buys it) is a form of over-production (Waste) that results in other forms of waste in Inventory, and can disrupt the flow of material through the production process.
Therefore, in a truly lean production system, nothing is produced until the customer (internal or external) pulls it through the system.
This Pull System should consist of a continuously flowing process where materials move through the value stream at the rate equal to the customer demand (Takt Time) in a smooth and uninterrupted sequence.
The Pull System is the opposite of a push system where materials are produced to a forecast and are held as inventory (waste of inventory) until they are needed.
Value can be pulled through a system using lean tools like a Kanban, which will be discussed below.
Core Principle #5 – Continuous Improvement
The 5th and final principle of the Lean Production System is to continuously improve toward perfection.
This core principle is why Lean Manufacturing is synonymous with Continuous Improvement and most lean practitioners are very familiar with the tools of Kaizen, 7 QC Tools, and other Continuous Improvement Methodologies.
Next: Lean Tools