Lean Manufacturing: Definition, Tools, and Implementation
To meet market demands and remain competitive, manufacturers continually strive for greater efficiency. In the past, companies operated with “full stock” to avoid production delays and supply shortages. Later, they shifted toward a “zero stock” model, which proved to be far more cost-effective.
Today, that model is considered risky, and many manufacturers now favor working with a “safety stock” approach—holding just enough inventory without excess. This also means shifting from a push-based production flow to a pull-based flow driven by actual demand. To support this new strategy, it is crucial to minimize all forms of waste. This is the central objective of Lean Manufacturing.
What Is Lean Manufacturing ?
Developed by Toyota Motor Corporation and widely adopted worldwide since the 1980s, Lean Manufacturing is a production management system.
Definition of Lean Manufacturing
Lean Manufacturing is an optimization method that seeks to reduce production time by eliminating waste. By conducting a detailed analysis of each step in the industrial process, manufacturers can identify and eliminate inefficiencies. As a result, customer expectations in terms of cost, quality, and lead time are met.
Lean is about producing better and at the right pace.
The English term lean refers to a production management method focused on “waste-free” or “just-in-time” operations. It involves carefully analyzing each step of the production process and eliminating all forms of waste (muda in Japanese).
Waste refers to anything that does not add value or that only has value for the company, not the customer. Eliminating waste leads to greater efficiency and profitability.
In practice, Lean aims to improve processes—requiring less space, effort, time, and capital, while also reducing defects and rework.
A Brief History of Lean Manufacturing
1913. Fordisme
Long before the term “Lean Manufacturing” existed, Henry Ford introduced the concept of Fordism.
Definition: Fordism is an industrial model that increases assembly line productivity through labor reorganization.
Ford’s model introduced key Lean principles:
- Waste and loss reduction
- Standardization of products, processes, and tasks
- Just-in-time supply chain: adjusting material flow to match actual demand
1924. Jidoka (autonomation)
Next, Sakichi Toyoda invented machines that could detect failures and stop automatically.
Definition: Jidoka is a method where machines stop as soon as a problem is detected to prevent the production of defective parts.
The goal of jidoka is to enhance quality by catching defects early in the process. The later a defect is discovered, the more costly it becomes. Sakichi Toyoda believed early detection was more efficient and cost-effective than quality inspections at the end of the line.
This innovation allowed operators to oversee multiple machines and intervene only when necessary. It introduced a human-centered production approach by making operators responsible for their equipment.
1962. Toyota Production System (TPS)
Over the next 30 years, Sakichi’s legacy was carried forward by his descendants, who shifted the company from textile machines to automobiles and developed the Toyota Production System (TPS), the foundation of Lean Manufacturing.
Definition: Toyotism is a supply chain model based on just-in-time principles. It advocates for a pull production model—parts and products are produced only when needed, in the right quantity, at the right time, and without waste.
This system contrasted with traditional Western methods, which focused on maintaining large inventories to push maximum production volumes regardless of actual demand. TPS was one of the first models to produce in response to real customer demand.
Understanding Lean Manufacturing and Its Core Principles
In the 1970s, to understand the success of Japanese companies, researchers studied their production systems. The term “Lean Manufacturing” emerged from these studies and referred to the reduction of production lead times and waste.
While initially thought to be relevant only to the automotive sector, further studies confirmed that Lean principles are simple and adaptable to any industry or business size.
The 5 Core Principles of Lean Manufacturing
According to Womack, Jones, and Roos, authors of The Machine That Changed the World (1991), Lean is about producing at lower cost, with shorter lead times, and higher quality. They defined five core principles:
1 : Identify Value
Clearly define the value created by team efforts—not just the price, but also the benefits perceived by the end customer.
2 : Map the Value Stream
The value stream includes all steps in the product lifecycle, from design to delivery. Once mapped, non-value-added activities (waste) must be identified and reduced.
3 : Create Flow
In Lean, all waiting times are considered waste. The production process must be fluid and continuous. Bottlenecks that hinder flow must be eliminated.
4 : Pull the flows
Once the flow is continuous, production should be regulated by downstream demand. Each step is triggered by the next one, minimizing inventory.
5 : Pursue Continuous Improvement
Improvement must be an ongoing part of the company culture. Focus on enhancing high-value processes and optimizing or eliminating low-value ones, always striving to reduce waste.
The 7 Types of Waste in Lean Manufacturing
Building on Taylorist principles, Lean focuses on performance through continuous improvement and the elimination of waste (muda) to enhance customer value. The seven types of industrial waste are:
Overproduction:
Producing more than needed or earlier than required leads to excessive inventory and processing.
Examples:
- Producing large batches unnecessarily
- Products going to storage or being discarded
Waiting:
Time lost when operators wait for a task or machine to finish.
Examples:
- Idle time between operations
- Machine cycles not synchronized
Transportation:
Time and resources spent moving materials unnecessarily.
Examples:
- Empty trips
- Intermediate storage requiring extra movement
Overprocessing:
Unnecessary steps that do not add value.
Examples:
- Overly complex tasks
- Excessive quality checks
Inventory:
Excess inventory ties up resources and space.
Examples:
- Obsolete stock from poor forecasting
- Stock not essential to current tasks
Unnecessary Motion:
Movement of personnel that adds no value.
Examples:
- Searching for tools
- Walking to collect data
Defects and Rework:
Producing non-compliant products results in waste.
Examples:
- Scrapped or defective parts
- Customer returns
Some experts also include an 8th form of waste: Underutilization of employee talent and knowledge.
Key Lean Manufacturing Tools
Several Lean tools have emerged from Japanese practices and are now widely used worldwide:
SMED (Single Minute Exchange of Dies)
Minimizes setup and changeover time, improving flexibility, reducing batch sizes and stock, and speeding up lead times.
5S Method
A five-step workplace organization method:
Seiri (Sort), Seiton (Set in order), Seiso (Shine), Seiketsu (Standardize), Shitsuke (Sustain).
It enhances cleanliness, order, and discipline in the workplace. « Seiri » pour éliminer tout ce qui est inutile.
‘Seiri’ to eliminate everything that is unnecessary.
‘Seiton‘ means putting tools and materials in a specific place so that they can be found immediately when needed.
‘Seiso’ means cleaning workstations, desks and production equipment. It is also a first step towards self-maintenance.
‘Seiketsu’ means standardising and clearly defining rules in the workplace. Visual management is frequently used for this step.
‘Shitsuke’ means following the rules mentioned above and, above all, encouraging and engaging staff to make 5S a real habit.
Poka Yoke
“Error-proofing” devices that prevent mistakes in assembly or connection tasks, aiming for zero defects.
Kaizen
A philosophy of continuous, incremental improvement that favors small, regular changes with long-term impact.
Implementing Lean Manufacturing with MES Software
A MES (Manufacturing Execution System) is often essential to successfully implementing a Lean Manufacturing strategy. By supporting real-time production monitoring, waste reduction, and continuous improvement, MES frees up time and resources to boost performance.
MES and Lean: A Powerful Combination
Although Lean and MES emerged decades apart, MES is designed to support Lean initiatives by helping eliminate the seven wastes. MES ensures the success of continuous improvement efforts—the foundation of Lean.
A reliable Lean strategy depends on accurate data collection, which a MES can provide. Manual data collection is often inefficient, error-prone, and time-consuming.
By digitizing and automating continuous improvement, MES facilitates change adoption by both operators and managers, leading to organization-wide engagement.
Far from replacing human input, MES empowers operators to take corrective action in real time.
MES: Supporting Lean Tools in Action
Tout d’abord, le logiciel MES est utilisé comme support pour les différents outils du Lean.
1 Real-time monitoring of OEE allows you to view all production data collected on machines or from operators to assess performance.
2 The implementation of instructions/checklists allows managers or continuous improvement managers to monitor 5S tasks.
3 Changeover time measurement with status and adjustment part tracking, accompanied by dedicated dashboards, provides accurate knowledge of SMED objectives.
4 With visual alerts to signal periodic interventions and visual guidance, operators are better equipped for self-maintenance (or preventive maintenance).
5 With AIC tables, which are used to display daily information on performance, safety, etc., and workshop displays with graphical indicators, MES is designed for visual management.
6 Visual guidance and Poka Yoke instructions accompany the operator to avoid errors and improve quality by working with dematerialised Poka Yoke.
In this way, MES platforms like Aquiweb play a vital role in successfully implementing Lean Manufacturing.