Lean techniques have been used successfully by organizations around the world for many decades to eliminate waste and increase productivity. Lean has what lean lacks - a systematic framework that enables its users to discover improvements that greatly surpass anything they might have found through traditional means. Lean provides a fresh approach to total quality management that moves beyond what is expected and beyond what lean has historically provided. Lean continually assures improvement through creative strategic management. By incorporating parallel and lateral thinking techniques, lean produces innovative results that surpass all prior efforts. The ability to generate ideas on demand enables users of Lean Plus to be more innovative. The synergy that is created when intentional innovation and lean work together, produces incredible results. The thinking framework and the ability to generate ideas on demand add value to the lean process by propelling it into the realm of a better quality, results-oriented process. Generating better ideas can be the breakthrough element to provide better solutions. The Lean program encompasses a broader perspective to explore and move beyond the reality of "What is?" to the possibility of "What can be?" The true benefit then of implementing lean is the overall strengthening of the system. If applied properly the lean methods will make any shortcomings in the system appear quickly, and the shortcomings will have profound impacts. If operations are closely linked utilizing single piece flow and one of the operations fails, how long will it take before all operations are also stopped? Not very long! This will cause the problem to gain immediate attention, and a high level of importance will be placed on correcting the problem and installing permanent preventive measures.
"Lean System"
Lean manufacturing is a generic process management philosophy derived mostly from the Toyota Production System (TPS) but also from other sources. It is renowned for its focus on reduction of the original Toyota 'seven wastes' in order to improve overall customer value. Lean is often linked with Six Sigma because of that methodology's emphasis on reduction of process variation (or its converse smoothness). Toyota's steady growth from a small player to the most valuable and the biggest car company in the world has focused attention upon how it has achieved this, making "Lean" a hot topic in management science in the first decade of the 21st century.
Introduction:
Many people commonly understand that lean manufacturing concepts and practices were developed for the Toyota manufacturing system. This is correct but Lean manufacturing history is little bit more than that.
Lean manufacturing concepts were used by some other very famous manufacturing system before Toyota. Lean system basically used as to solve problems like control of waste, improve attitude towards workers, inflexibility. Lean manufacturing do not have single solution for all the industries, and every occasion. Failing to understand this will be a fetal mistake in the process of implementation. Before even thinking about implementing, there are many fundamentals anybody has to understand.
Terms:
There are many special terminology associated with lean manufacturing. Some terms are used with different meanings in lean manufacturing context e.g., term "waste" has a different meaning in lean manufacturing.
Waste:
It is defined as anything that does not add value to the final product. Elimination of waste is the goal of Lean. Toyota defined three types of waste: muda or no value-added work, muri or overburden and mura or unevenness. The original seven muda 'deadly wastes' are:
Overproduction
Transportation
Waiting
Inventory
Motion
Over Processing
Defects
Term like SMED is special to the lean manufacturing. SMED or the Single Minute Exchange of Dies is a technique developed for the Toyota production system to reduce the setup time.
Definition:
Lean manufacturing definition has given many forms according to the views of authors and practitioners. It is obvious that a system like lean manufacturing can not be explained with a single sentence. But lean manufacturing can be defined generally as follows:
"Lean manufacturing is the system which aims in elimination of the waste from the system with a systematic and continuous approach"
Lean Manufacturing is "A systematic approach to identifying and eliminating waste through continuous improvement by flowing the product at the demand of the customer."
"Toyota Lean System"
Lean manufacturing implementation process must be well planned, step by step process. Importantly it should have contingency plans. Everything will not go as you intend or planned. It is also very important to remember that there is no one way to achieve success in lean manufacturing. Lean manufacturing techniques and tools must be used to overcome the problems. But you must always stick to the lean manufacturing concepts and principles. This is why many lean manufacturers say "lean thinking is universal not the processes at Toyota".
History of Toyota Lean System:
The manufacturing revolution began in Japan, with Toyota family, when they shifted from textile equipment manufacturing to Automobile manufacturing. By late 1940's Japan industry was collapsed and economy was badly affected by the World War II. In addition, Japanese manufacturers faced many problems. Limited sources of raw materials, labor movements, and limited capital availability are few of them. Meanwhile, automobile manufacturers faced another problem. They could not compete with the already existing (Although declining) forces of west. Especially players like Ford, simply out performed small manufacturers like Toyota. Therefore they could not compete on the overseas markets. This made Japanese manufacturers to produce for their local markets. These markets were very diversified and small.
Challenged by these demands Toyota gave the task of making a system which will stand in these conditions to Taichii Ohno. Ohno with his colleague Shingo created a manufacturing system for next three decades, which is known as Toyota Production System (TPS). The Toyota Production System (TPS), which is better understood as the "Thinking People System" or simply the Toyota way, enables operational excellence by creating an organization that values and respects people and their creative abilities.
The roots of this system were clearly linked to the Ford's system. Actually all the managers in Toyota said to learn the Ford's system. Fortunately though, they did not simply copy the Ford's system. Instead they clearly understood the pluses and minuses of the system. They impart the Pluses to their system, while eliminating the problems. This manufacturing method got the influence of the Quality movements in USA. Especially thinking of people like Juran and Deming influenced the Toyota production system.
Starting from mid 1940s to 1970s Toyota production systems was developed continuously. By this time TPS was doing very well. With the economic problems Japan faced in the years 1974, many Japanese companies experienced losses. But Toyota was continuo to be a success even in this period. This made many Japanese manufacturers to look in to this system as an alternative to their problems. JIT or TPS started gaining popularity within Japan.
Today, lean manufacturing has got the next step in its development. Lean manufacturers now become lean enterprises. Lean manufacturing stretch out from the factory premises to all of stake holders. This includes suppliers, customers and all the influencing parties. Lean enterprise concepts are focused on all the people in the supply chain to get the best possible value from the collective effort. Lean manufacturing makes history even today, with a very high phase.
Implementation of Toyota Lean System:
Following the successful implementation of Toyota's manufacturing system, many other companies in Japan, such as Honda Motor, Mitsubishi Heavy Industries, Nippon Co. Ltd., and Sony Electric, as well as companies in the U.S., such as Lockheed Martin, Boeing, and Fluke Corporation, followed suit with equal success.
The focus on value is central to the success of TPS. TPS designates waste as muda in Japanese. One of the principal ways to reduce waste is to ask whether the customer is willing to pay for the feature in question. If the answer is "no," then TPS designates it as waste. TPS identifies seven wasteful activities that consume time and can be eliminated once identified:
Overproduction
Waiting
Unwanted transporting
Inappropriate processing
Unnecessary inventory
Excessive movement
Defects in the product or process that requires reworking or repair
Toyota's firm belief in its production system has translated into solid profits for the company. In May 2007, it announced an annual profit of $14 billion. In 2006, its profits rose by nearly 17%, making it the world's most profitable company. Toyota's vehicles continually top the quality-ranking charts. Today, the company is known for its flexibility, efficiency, and high productivity levels.
System Engineering:
Lean is about more than just cutting costs in the factory. One crucial insight is that most costs are assigned when a product is designed. Often an engineer will specify familiar, safe materials and processes rather than inexpensive, efficient ones. This reduces project risk, that is, the cost to the engineer, while increasing financial risks, and decreasing profits. Good organizations develop and review checklists to review product designs.
For example, adjustments may be moved into software and measurements away from a mechanical solution to an electronic solution. Another approach is to choose connection or power-transport methods that are cheap or that used standardized components that become available in a competitive market.
Example:
Examples of a lean implementation program with muda and with muri are:
Muda:
With a muda or tools based approach the example of lean system will be:
Senior management to agree and discuss their lean vision
Management brainstorm to identify project leader and set objectives
Communicate plan and vision to the workforce
Ask for volunteers to form the Lean Implementation team
Appoint members of the Lean Manufacturing Implementation Team
Train the Implementation Team in the various lean tools - make a point of trying to visit other non competing businesses which have implemented lean
Select a Pilot Project
Run the pilot for 2-3 months - evaluate, review and learn from your mistakes
Roll out pilot to other factory areas
Evaluate results, encourage feedback
Stabilize the positive results by teaching supervisors how to train the new standards you've developed with TWI methodology (Training Within Industry)
Once you are satisfied that you have a habitual program, consider introducing the next lean tool. Select the one which will give you the biggest return for your business.
Muri:
With a muri or flow based approach example of Lean System will be:
Sort out as many of the visible quality problems as you can, as well as downtime and other instability problems, and get the internal scrap acknowledged and its management started.
make the flow of parts through the system/process as continuous as possible using work cells and market locations where necessary and avoiding variations in the operators work cycle
introduce standard work and stabilise the work pace through the system
start pulling work through the system, look at the production scheduling and move towards daily orders with kanban cards
even out the production flow by reducing batch sizes, increase delivery frequency internally and if possible externally, level internal demand
improve exposed quality issues using the tools
remove some people and make it all work again
Successful implementation of a Lean operating system, whether in manufacturing, distribution, healthcare or administrative work requires an understanding of not only the systems and tools but the underlying values and behaviors that make up the Toyota Production System.
Values: The Toyota Way
What makes Toyota successful is not a set of manufacturing methods or improvement tools, but a particular mindset that leads to taking action. This mindset is based on values including:
Build quality in rather than inspect it in
Flow
Kaizen
Genchi genbutsu - go to the source to get the facts
Empowerment
Standardization
Visualization
Eliminate waste
By following these guiding principles and incorporating these values into how you design your Lean operating system, you can achieve Operational Excellence.
The Toyota Production System House
The house was chosen as a way to visualize the TPS model because it is a universally recognizable image, and because the metaphor of the pillars and foundation supporting the roof was an easy way to represent a system.
Just in Time
Jidoka
Standard Work
Kaizen
Heijunka
Skills: The Thinking People System (TPS)
There are various ways to do kaizen, whether as projects or as part of daily work:
Creativity & Craft Programs (Suggestion Systems)
QC Circles
Kaizen Events / Kaizen Workshops
Jishuken
Technical kaizen projects
Knowledge: The Kaizen Tool Kit
These tools are used to eliminating waste, continuous flow, build in quality and make problems visual.
5S
SMED
TPM
Kanban
Visual Management / Visual Controls
Multi-process handling
Production Preparation Process (3P)
Pokayoke
Commitment: What does it take?
Long-term commitment
New management philosophy
Performance aligned with business objectives
Cross-functional participation
Focus on productivity
No-layoff policy
Kanban System:
In the TPS, a unique production control method called the "kanban system" plays an important role. The kanban system has also been called the "Supermarket method" because the idea behind it was borrowed from supermarkets. Supermarkets and mass merchandizing stores use product control cards on which product-related information, such as product name, product code, and storage location, is entered. Because Toyota employed kanban signs in place of the cards for use in production processes, the method came to be called the "kanban system." At Toyota, when a process goes to the preceding process to retrieve parts, it uses a kanban to communicate what parts have been used.
Relation between Lean Manufacturing and Waste:
There is a direct relation between lean manufacturing and waste (muda). Lean manufacturing aims to reduce variables related to inventory, delivery, cycle, and setup time. Furthermore, it endeavors to elevate quality, boost customer satisfaction, and encourage employee participation and esteem within the organization.
Benefits of Lean Manufacturing:
Lean manufacturing also achieves benefits such as eliminating waste by creating a culture of constant improvement that centers on the needs of the customer. It features a set of key principles, as shown below:
Cellular manufacturing:
Cellular Manufacturing involves the stationing of manufacturing units, equipment, and crew members as "cells," allowing for an unbroken and even movement of inventory and material from start to finish. This usually entails a single process/product flow line.
Pull scheduling:
Pull scheduling involves setting up effective and inexpensive methods of managing production and inventory. Many manufacturers also use the Japanese system of Kanban to implement pull scheduling.
Six Sigma and total quality management:
Six Sigma and total quality management involves the application of an effective quality-control system to eradicate product and system defects from the production process.
Rapid Setup:
Rapid setup is also known as single-minute exchange of die (SMED) and calls for quick and predictable setup. It helps reduce setup costs and allows production of smaller lots. It also rationalizes the flow of material during the manufacturing process.
Lean manufacturing complements TPS in many ways, as both focus on the customer and attempt to understand future market trends. Both systems require a top-down management approach and the capacity to allow employees to make local decisions. Both systems require the willingness, persistence, and faith that are in many ways counterintuitive to conventional learning systems. If they implement lean manufacturing properly, companies stand to gain by blending the core principles of these highly regarded philosophies.
Customers Benefit From Lean Manufacturing
Element
Functional
Cellular
Improvement
Response
Weeks
Hours
70%-90%
Customization
Difficult
Easy
Competitive Advantage
Delivery Speed
Weeks-Months
Days
70%-90%
Delivery Reliability
Erratic
Consistent & High
Up To 90%
Delivery Quantities
Large Shipments
JIT As Required
Locks In JIT Customers
Quality
Erratic
Consistent & High
Delighted Customers
The customer sees improved quality and this is an obvious benefit to both customer and supplier. Customers see faster response to unusual requests for customized products or accelerated delivery. They see faster and more reliable average deliveries that make their tasks easier. Cellular manufacturing allows manufacturers to deliver small quantities reliably without holding large inventories. The inherent quality improvements in a cellular layout also find their way to appreciative customers.
When suppliers implement Lean Manufacturing, customer response is often the most obvious improvement. Response refers to the time required for the manufacturer to react to customer needs. Fast, reliable deliveries are a characteristic of cellular manufacturing. This is because the reduction of queues and inventory speed products and components through the system. When fast delivery is a requirement for a given market, fast throughput or an extensive finished goods stock are the only options. In some markets, fast delivery is not important, but reliable delivery is. This means that the manufacturer delivers the product when it says it will deliver.
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Quality Benefits From Lean Manufacturing
Element
Functional
Cellular
Improvement
Responsibility
Fragmented
Focused In Cell
50%-90% Improvement
Approach
Police Action
Self-Enforced
Happier Teams
Motivation
Avoid Punishment
Pride
Peak Performance
Problem Solving
Difficult & Fragmented
Team-Based
Permanent Solutions
Functional layouts require the product to move many times between departments with a separate operation at each department. When the product is defective, it is often difficult to pinpoint where the defect has occurred. In a cell, most or all operations occur in one area and among a small team. This focuses responsibility and motivates the team to avoid similar defects in the future.
While Statistical Process Control techniques can improve functional operations, they are easier to apply and more effective in practice with a work cell environment. Most functional layouts use a sort of? Quality Police?, the Quality Control Inspectors, to enforce quality. With teams and work cells, quality is more likely to be self-enforced.
Feedback on quality problems is faster and surer in a cell than it is in a functional arrangement. This is because the various processes and people are very close, usually within conversational range. Since teams are often used within cells, team spirit motivates quality improvements. Because the operations in a functional layout are scattered, problem solving that cuts across departmental boundaries is difficult. Departmental loyalties work against it. The coordination of information from many sources works against it. Forming an effective problem-solving group is problematic. Cellular environments generally have a functioning work team. When this team switches to a problem-solving mode, the team is immediately effective.
Inventory & Scheduling Benefits From Lean Manufacturing
Element
Functional
Cellular
Improvement
Lot Sizes
Large
Small
50%-100%
Queues
12-30
3-5
50%-80%
Stocking Policy
Make-To -Stock
Make-To-Order
Eliminate FG Stock
Inventory Turns
3-10
15-60
60%-90%
Throughput
Weeks
Hours
50%-90%
Equipment Utilization
40%-100%
20%-80%
Functional Utilization Often Unrealized
Scheduling
Complex (MRP)
Simple (Kanban)
Much Easier
Lean manufacturing benefits extend to inventory scheduling and production control. The functional layout presents severe scheduling and inventory control difficulties. Cellular layouts simplify the underlying process and thereby simplify scheduling.
Every inter-departmental move requires an outbound queue and an inbound queue. Such queues tend to be quite large because it is difficult to precisely time the completion of each operation and coordinate the subsequent move. Cellular operations dramatically reduce material movement. This consequently reduces the number of queues and the inventory in each queue.
Lot sizes tend to be larger in a functional environment. This partly results from the complexity of scheduling. It seems easier to schedule a small number of large lots rather than a large number of small lots. Equipment selection also plays a role. Functional layouts lend themselves to large-scale equipment. Such equipment processes a wide range of products and increases the volume for a given process. Large-scale equipment also tends to reduce direct labor and appears to be more efficient. But large-scale equipment is often difficult to setup. It must address a wider range of products. Expensive, large-scale equipment requires high utilization. High utilization requires more inventories.
Average throughput time is directly proportional to inventory. When inventories shrink in a cellular environment, average throughput time shrinks proportionately. The reduction in inventory frees up capital and space for more worthwhile investment. The improved throughput time improves customer response and helps stabilize the system.
Duplication of equipment in cells seems to cause low utilization. Several factors can mitigate this:
The wide variation in production requirements that characterizes functional arrangements often results in lower utilization than one would otherwise expect.
Work cells typically produce only a limited number of products out of the factory's product mix. They therefore need smaller-scale, lower-volume equipment.
Cellular equipment is often simpler and less expensive than corresponding equipment in a functional arrangement. Therefore, low utilization in a cell is less important.
The capital freed by inventory reductions usually provides more than enough money for additional equipment. In effect, work cells trade inventory for excess capacity. This tradeoff is usually quite favorable.
Cells may share equipment and thereby reduce duplication. Certain operations can remain centralized.
The designer can often build work cells around specific pieces of large-scale, expensive equipment. Duplication is then reserved for low-cost equipment in secondary operations.
Functional layouts usually require the capabilities of Materials Requirements Planning (MRP) systems. These systems are complex, expensive, and cumbersome. A a cellular layout allows simpler scheduling approaches such as kanban and broadcast.
Material Handling Benefits From Lean Manufacturing
Element
Functional
Cellular
Improvement
Inter-department Moves
Many
Few
50%-90%
Travel Distance
500'-4000'
100'-400'
70%-90%
Routings
Complex
Simple
Possible Automation
Route Structure
Variable
Fixed
Simplified
Lean manufacturing benefits include those from material handling.Fewer moves, shorter travel distances, and simpler route structures add up to impressive savings. These characteristics also contribute to savings in inventory, coordination and quality.
The product-focused cellular layout has fewer interdepartmental moves compared to a functional equivalent. This reduces handling frequency and cost by as much as 90%. The cellular layout also reduces the queuing, delays, tracking effort, and confusion that accompany material movement.
Travel distances are shorter in the cellular layout. In addition to reducing the cost of long moves, this improves communication and often enables visual control systems.
Complex routings are characteristic of functional layouts. Many products and components visit multiple work centers in multiple sequences. This, in turn, necessitates complex process plans and extensive documentation. Cellular routings are simple.
Functional layouts have variable route structures since many products move in so many different directions. This necessitates costly handling devices such as fork trucks or Automated Guided Vehicles that can accommodate such variable route structures. The cellular layout, by contrast, has simpler and more stable route structures that may allow simple and cheap handling devices such as conveyors and chutes.
Object of Toyota Lean System:
The Toyota "Lean" System was built on objectives mostly focused on survival and on building a company culture around an engaged organization of people trying to do something. For Toyota, at the time that something was "Catch up with America." For them it was, "Be there for their customers."
Taiichi Ono said, "Toyota production system was born because, it had to be born." Lean System is helpful to Toyota because:
Customer value is the focus. Make that value visible and the center of everyone's work.
Put all value creation steps into sequence. Look at work as a process, not departments.
Make the value creation steps flow with no stops in between. Drive
velocity or cycle time through the value creation by working one item at a time.
Work only when the customer demand is created. Make sure the work you do is what your customer is paying you to do.
Drive for 100% on-time, with the right product and service every time the first time.
In recovery, waste cannot be tolerated anywhere. The company striving to become a "Lean Enterprise" will have a distinct advantage over those that are not, especially in difficult times. Whether or not you are recovering from a Katrina, Wilma, Tsunami or fire, using the lean enterprise principles can guide you to achieving company performance well beyond that to which you are accustomed to in a more traditional command and control management system.
Lean manufacturing technique:
Prime objective of waste elimination from the system is achieved with lean manufacturing technique and all tools. Based on this requirement, Just In Time (JIT) techniques, Total Quality Management (TQM), Total Productive Maintenance (TPM), Flow charts, Workplace Redesigning techniques are used. Basically, lean manufacturing technique consists of four steps.
First step is to realize that there are wastes in the system to be removed. Although this seems like a crazy idea, this is the step which creates the requirement for the movement towards lean manufacturing. Many organizations do not realize that they have tons of hidden wastes with them. Therefore they do not have the requirement to remove them from the system. So they will have their problems forever and they will try to find solutions for these problems forever.
Once you realize that there are wastes to be removed from the system, in the second step, you will identify the different forms of that waste. Further, in this step you will identify the causes for these wastes. This is very important step in the process. Lean manufacturing never promotes treating the symptoms. Rather it believes treating the causes and cures the problems permanently. In this step tools like Ishikawa diagrams or cause and effect diagrams can be used for good effect.
In the third step, comes the solution finding for the identified root causes. One golden rule to be followed in this step is adhering to the basic lean manufacturing principle of seeing the total picture. Do not find solutions by only looking at causes on their surface. It is very important to identify the solution. It is even more important to identify the effect of the solution to the entire system. For an example if you are trying to reduce the line down time, it is very important to make sure the solution is not going to increase the lot sizes heavily and make the net effect on the organization a negative.
Final step is the implementation process and making sure things are going in the intended way. Here the solutions will be tested and implemented. Then these solutions will be tweaked to accommodate practical difficulties occur in the implementation process. User training and follow-up are among the most important things in this step of lean manufacturing technique. This step generally takes long time.
In each and every step mentioned above, many tools will be used to achieve the goals of each step. Make sure to look at the entirety, not a part of the problem. Solution you find must have a positive effect on the entire system.
Elements of Toyota Lean System:
Machine describes how Toyota operates the five elements of its lean business system. These are as follows:
Product design
Supply chain coordination
Customer relations
Production
Enterprise management.
Success of a lean implementation :
Problems will surface quickly and obviously (at times painfully).
A sense of urgency will automatically be created regarding system reliability.
The weakest point of the system will be stressed and broken.
Operations will be forced to be close to the edge and as tight as possible.
Consistent application in all areas and in the thinking and development of our practices.
Indications of the success of a lean implementation are:
Problems will surface quickly and obviously (at times painfully).
A sense of urgency will automatically be created regarding system reliability.
The weakest point of the system will be stressed and broken.
Operations will be forced to be close to the edge and as tight as possible.
Consistent application in all areas and in the thinking and development of our practices.
Example:
Toyota's Georgetown, Kentucky plant is Toyota largest in the world outside of Japan. It has a total throughput time of just 22 hours. In other words, operating on two 10-hours shift per day, coils of steel received first thing Monday morning will roll off the assembly line as finished automobiles sometimes early Tuesday morning.
In 2004 the Toyota Motor Company had operating income of 9%. This was 45% higher than its nearest U.S. competitors. Toyota's U.S. market share has grown faster than any other major competitors. The chart below shows the company's remarkable success in the United States.
U.S. Automobile Market Share Change
1990
2005
% Change
General Motors
35.5%
27.3%
(23%)
Ford
23.9%
18.3%
(23%)
Daimler Chrysler
12.2%
13%
7%
Toyota
7.6%
12.2%
61%
Honda
6.2%
8.2%
32%
Nissan
4.5%
5.8%
29%
Other
10.1%
15.2%
51%
In 2004, Toyota has less than a dozen re-calls. Their U.S. competitors each have well over 100 every year. In the past twenty year, Toyota has created over 50,000 jobs in United States, while competitors are forced to lay workers off as more and more plants are closed. Below is a table showing the profit per vehicle of major US car companies. Only Nissan makes more profit per vehicle, but they also command just 5.8% of the US Market share. Not only is Toyota big, but they are also very efficient.
2005 profit per vehicle in the United States
Nissan
$1,603
Toyota
$1,480
Honda
$1,250
Ford
$620
Daimler Chrysler
$186
General Motors
($2,311)
Toyota currently builds 4 models of hybrid cars. On March 31, 2002 the company built its 100,000-th hybrid car giving it a whopping 90% of the hybrid market at the time.
Some companies in Japan that have successfully implemented the Toyota Production System:
Hitachi Chemical Company Limited
Nippon Company Limited
Fuji Electronic Company Limited
Honda Motor Car Company Limited
Mitsubishi Heavy Industries Company Limited
Sony Electric Company Limited
Olympus Optical Company Limited
Hundred of other manufacturers
Conclusion:
Many business processes and especially manufacturing are based on serial processes, where things are passed down a chain of processes, with value being added at each point. Within this system there is massive opportunity for inefficiency and waste, such as buffer stores, things getting lost, breakdowns, etc.
A lean system has none of this fat. Going lean means removing all waste from the system. This has much suggestion, such as:
Gaining a true understanding how things work so you can constantly improve, reduce waste and increase efficiency.
Reducing buffer storage to the absolute minimum, which makes everything connected: if one point in the system breaks down, everyone is very rapidly also affected.
Attention to bottlenecks, including when up-stream to suppliers and downstream to customers.
Being able to rapidly change the system to work on different products.
Having flexible, multi-skilled people who can perform such changes.
Having systems and management that engenders such a capable and motivated workforce.
Thus parts and material should arrive at any point just as they are needed, and not before. This is known as Just In Time (JIT) and is the perfection that is sought, and can be far more closely attained than old systems which use large buffer stores to cover up inefficiencies in the system. JIT principles have been adopted in many other areas further field from the original factory floor. For example Just In Time software compilers compile code just before it is needed.
Toyota is consistently recognized as a leader and originator in this methodology (which helps to explain why many of the terms associated with it are Japanese).
The Toyota Motor Company is clearly doing something right. As any business leader knows, such repeatable successes do not happen by accident. They are the result of commitment, passion and the pursuit of excellence. For a manufacturer to become lean and follow Toyota's footsteps is not impossible. Bit it is not easy, if it was, every company would be lean and Toyota's numbers would not be look that impressive. Literally thousands of companies worldwide have successfully made the transaction to lean manufacturing. Below are just a few examples.
Bibliography
http://books.google.com.pk/books?hl=en&id=7_-67SshOy8C&dq=lean+manufacturing&printsec=frontcover&source=web&ots=YlRtu8Bly_&sig=8LvsoJCkjoSiYoKCuifsS7KI6Js
http://en.wikipedia.org/wiki/Lean_manufacturing
http://syque.com/improvement/Lean%20systems.htm
http://www.sae.org/topics/leanmar01.htm
