History of lean manufacturing
The origins of lean manufacturing trace back to Toyota Motor Corporation in Japan during the 1930s, long before the term “lean” was coined.
Toyota’s engineers observed that a steady, uninterrupted production flow significantly reduced waste caused by frequent stoppages, restarts, and excess inventory. This principle became the foundation of the Toyota Production System (TPS), which has since become the world’s most influential manufacturing framework.
Key milestones in lean manufacturing history
| Year | Milestone |
|---|
| 1930s | Toyota develops early concepts of production flow |
| 1950s | Taiichi Ohno formalises TPS and identifies seven types of waste |
| 1970s | Just-in-Time (JIT) system adopted across Toyota plants |
| 1988 | Term “Lean Manufacturing” coined by John Krafcik (MIT) |
| 1990 | The Machine That Changed the World published, popularising lean globally |
| 2000s | Lean expands beyond automotive to healthcare, software, and services |
| Present | Integration of Lean with Industry 4.0, giving rise to Lean 4.0 |
Toyota’s TPS demonstrated that companies could produce more, generate less waste, and better serve customers — a principle that permanently reshaped global manufacturing philosophy.
Principles of lean manufacturing
Lean manufacturing is built on a set of principles that help businesses improve efficiency, reduce waste, and deliver higher value to customers. Below are the eight key principles:
- Define Value: Understand what the customer really wants and is willing to pay for, including price, delivery time, and product features.
- Map the Value Stream: Look at the full journey of a product, from raw materials to disposal, and identify every step. Any step that doesn’t add value is waste and should be reduced or removed.
- Create Flow: Make sure all value-adding steps happen smoothly, without interruptions, delays, or bottlenecks.
- Establish Pull: Produce products only when there is real customer demand, rather than based on forecasts. This avoids overproduction and lowers inventory costs.
- Pursue Perfection (Kaizen): Lean is a continuous process. Always review and improve operations to remove more waste and deliver maximum value to the customer.
Types of waste in the lean manufacturing process
Waste in lean management is a complex concept that requires a thorough approach. Addressing waste superficially can result in only limited reductions. To achieve optimal results in lean project management, it’s essential to identify and eliminate all types of waste.
Taiichi Ohno, chief engineer at Toyota, introduced the seven types of waste as part of the Toyota Production System (TPS):
- Unnecessary transportation: This refers to the inefficient movement of employees, materials, or equipment. By optimising factory layouts, unnecessary transportation can be reduced, saving time and resources.
- Excess inventory: Holding too much inventory can lead to problems such as delayed detection of defects and longer lead times. Lean practices encourage keeping only the necessary stock to avoid these issues.
- Unnecessary motion: Inefficient movements of people, equipment, or machinery during production contribute to waste. This can be minimised by using scientific management techniques to streamline operations.
- Waiting (Idle workers or equipment): Waste occurs when workers or machinery are idle, either because materials or equipment are delayed, or maintenance hasn’t been completed. Efficient planning can prevent these delays.
- Overproduction: Producing more than is needed leads to excess inventory and other inefficiencies. Lean manufacturing promotes just-in-time production, where only the products that are demanded by customers are made.
- Over-processing: Adding features or components that are not required by the customer is another form of waste. Lean practices focus on delivering what the customer values, avoiding unnecessary processes.
- Defects: Defective products lead to waste in terms of rework and customer dissatisfaction. Reducing defects is key to lean management, as it cuts costs and improves quality.
Additionally, lean experts have identified an eighth type of waste—unused talent or ingenuity. This occurs when employees' input is overlooked in identifying waste and improving processes, limiting the potential for innovation and efficiency. Businesses can consider green marketing strategies to leverage these insights for both environmental and operational efficiency.
By addressing all these types of waste, lean manufacturing aims to create more value with fewer resources.
Techniques of lean manufacturing
Applying lean principles requires practical tools and methods that help reduce waste, streamline processes, and improve efficiency. Some of the widely used lean manufacturing techniques include:
- Kanban boards: A visual workflow management tool that helps assign, track, and prioritise tasks. It ensures smoother coordination, avoids idle time, and focuses efforts on activities that add the most customer value.
- Gemba: A Japanese term meaning "the real place," it involves managers physically visiting the production floor to observe processes directly, identify waste, and make practical improvements instead of relying only on reports.
- Andon: An alert system used on the shop floor where operators can signal issues such as equipment failure, material shortage, or quality concerns. This ensures quick problem resolution and prevents production delays.
- Poka-yoke: Also known as error-proofing, it uses simple mechanisms or devices to prevent mistakes. For example, machines that require a safety step before operation reduce the chance of errors and accidents.
- Hoshin Kanri: A strategic planning method where top management sets long-term goals and aligns them across all levels of the organisation, ensuring that every employee’s efforts contribute to the same objectives.
- Total productive maintenance (TPM): A proactive approach where operators are trained to maintain and monitor their machines, reducing downtime, preventing breakdowns, and improving productivity.
- 5S methodology: A workplace organisation practice involving Sort, Set in order, Shine, Standardise, and Sustain. It promotes cleanliness, safety, and efficiency, ensuring an uncluttered and productive shop floor.
- 5 Whys: A simple problem-solving tool where teams repeatedly ask "why?" until the root cause of an issue is identified. This helps in preventing recurring problems and implementing lasting solutions.
- SMED (Single-Minute Exchange of Die): A technique that reduces machine setup or changeover time to under 10 minutes. It allows operators to perform some steps while the equipment is still running, minimising production stoppages.
Benefits of lean manufacturing
Adopting lean manufacturing principles enables companies to achieve a range of benefits:
| Benefit | Impact | Measurable outcome |
|---|
| Increased efficiency | Faster production using fewer resources | Typical 20–50% reduction in production time |
| Cost reduction | Minimises waste, lowers inventory, optimises resource use | 10–30% savings in operational costs |
| Better product quality | Defects identified and eliminated at the source | Significant reduction in rework costs |
| Higher customer satisfaction | Quicker delivery and consistent quality | Improved Net Promoter Score (NPS) |
| Employee morale | Staff engaged in improvement initiatives feel valued | Lower attrition and higher employee engagement |
| Improved cash fow | Less capital tied up in excess inventory | Faster inventory turnover |
| Environmental sustainability | Reduced material waste and energy use | Lower carbon footprint |
| Competitive advantage | Leaner, faster, and more responsive operations | Gains in market share |
Examples of lean manufacturing
- Poka-Yoke (Mistake-Proofing): Designing processes so mistakes cannot happen. For example, a microwave that won’t start until the door is fully closed. In factories, safety mats can stop a machine if someone gets too close.
- Kanban (Visual Signals): Using visual cards or digital signals to manage material flow. For example, a bin of parts may have a card at the bottom that signals the supplier to deliver more when it is reached.
- Cellular Manufacturing: Machines are arranged in small “cells” so a part can be completed in one area instead of moving along a long assembly line. This can greatly reduce the distance a part travels—for instance, from 1.5 miles down to 100 feet.
- SMED (Single-Minute Exchange of Die): A method to reduce machine setup times. One cable factory used SMED to cut a 5-hour changeover down to just 35 minutes.
How to implement a lean manufacturing system
The five core lean manufacturing principles are value, value streams, flow, pull, and perfection. These principles help organisations optimise efficiency while delivering maximum value to their customers. By following this framework, businesses can streamline operations and enhance customer satisfaction. The approach to guerrilla marketing can also benefit lean businesses aiming to attract customers with limited resources.
Here are some key steps to implementing lean manufacturing:
- Identify value: Determine what activities in the production process provide value to the customer and what do not.
- Map the value stream: Identify the steps in the production process and create a value stream map to visualise the flow of materials and information.
- Eliminate waste: Analyse the value stream map to identify non-value-added activities and eliminate them.
- Build a culture of continuous improvement: Encourage employees to suggest process improvements and make changes based on feedback and data analysis.
- Implement just-in-time inventory: With just-in-time inventory, companies bring in materials and resources as they are needed, reducing the costs of holding excess inventory.
- Monitor and evaluate: Track progress and make adjustments as necessary. Continuously monitor for waste and seek opportunities for improvement. By understanding entrepreneurship, entrepreneurs can apply lean principles to their businesses effectively.
Differences between lean manufacturing and six sigma
| Feature | Lean Manufacturing | Six Sigma |
| Primary Focus | Improving efficiency and reducing waste | Reducing defects and variation |
| Main Goal | Deliver maximum value to the customer using fewer resources | Achieve almost perfect output (3.4 defects per million) |
| Methodology | Five Lean Principles: Value, Value Stream, Flow, Pull, Perfection | DMAIC: Define, Measure, Analyze, Improve, Control |
| Primary Tools | Kanban, 5S, Value Stream Mapping, Kaizen | Statistical analysis, Control Charts, FMEA, Regression |
| Organisation | Focus on culture and teamwork, with flatter hierarchies | Structured hierarchy with belts from White to Master Black Belt |
Difference between lean manufacturing and just-in-time manufacturing
| Feature | Just-In-Time (JIT) | Lean Manufacturing |
| Primary Focus | Managing inventory and improving efficiency | Creating customer value and reducing all types of waste |
| Scope | Narrow; mainly shop floor and supply chain | Broad; includes all departments such as marketing, HR, and more |
| Main Goal | Produce only what is needed, when it is needed | Remove all activities that do not add value |
| Personnel | Production staff and supply chain partners | Entire organisation and stakeholders |
| Flexibility | Less flexible; works best in stable processes | Very flexible; adapts to changing market demands |
How business loans support lean manufacturing implementation
Investing in lean manufacturing requires an initial investment in training, equipment, and facilities. If you are looking to implement lean manufacturing but need funds, consider getting a business loan. You can apply for a Bajaj Finserv Business Loan of up to Rs. 80 lakh with interest rates starting at 14%.
Lean manufacturing offers a revolutionary approach to streamline production processes and create value for customers. By following the lean manufacturing principles and implementing a culture of continuous improvement, companies can improve efficiency, reduce waste, and boost customer satisfaction. If you are looking to implement lean manufacturing in your own organisation, consider getting a Bajaj Finserv Business Loan to help finance the initial investment.
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