Lean manufacturing is a process of removing waste that was developed by the Toyota Production System. The concept behind lean manufacturing is defined by three different forms of waste: "muda" or non-value-added work, "muri" or overburden and "mura" or unevenness. By eliminating waste, overall quality can be improved and production time as well as cost can be reduced.

Toyota further breaks down the wastes into the following categories:

• Over-production (production ahead of the demand)
• Waiting Time (waiting for the next production step)
• Transportation (moving products that are not required to perform the processing)
• Over-Processing (Poor tool or product design creating activity)
• Inventory (Finished product not being finished)
• Motion (people or equipment moving or walking more than the production requires)
• Defects (Effort involved in identifying and fixing defects)

Lean Manufacturing focuses entirely on solving the problem of waste through a constant process of analysis, production and mistake-proofing. Lean Manufacturing is a holistic, comprehensive, enterprise-wide program designed to be integrated into your company's core strategy. Many experts believe Lean Manufacturing strategy is the most effective way to launch and sustain lean activities. A second process of Lean Manufacturing is improving the `flow' or the smoothness of the work. Toyota developed this added process to improve the flow instead of focusing on waste reduction. The Flow is designed to produce goods at a constant rate and allow further processing to be carried out at a constant and predictable rate.

Lean Manufacturing is focused on "the right" that is; getting the right things to the right place at the right time in the right quantity. During this "right" process the Lean Manufacturing system also strives to achieve perfect work flow while minimizing waste and being flexible to change.

Lean Manufacturing does lead to the overall reduction of costs in your factory, but it also teaches that most of the "extra" costs are assigned when the product is first designed. Many times it has been noted that employees will specify familiar, safe materials and processes rather than search for a new one. This tends to lead to expensive and inefficient programs and/or processes.

When you implement lean manufacturing, you should start by setting up a checklist and review it often. Product design can be cut in half with a few brainstorming sessions that improve overall company cost and performance. Lean Manufacturing also requires the use of an effective, efficient leader. Lean Manufacturing focuses on a complete cultural change to your business. Toyota has used a system of coaching and guiding series to help the less experienced companies become proficient in their division.

Many companies have had outstanding results from implementing Lean Manufacturing. Cefla Group published they have accelerated business process by 87%. General Motors has implemented Lean Manufacturing to cut down administration costs. They reported a $200 million dollar savings for halting the printing of catalogs for dealers. Chrysler also reported savings upward of $2 million by implementing Lean Manufacturing. Many other companies have reported cutting costs by 10% to 40% and increased productivity by 12% to 52%.

Criticisms of lean manufacturing

Common problems with lean manufacturing tend to remove around the key principles and if they make sense. For a rational thinker, very few of the principles will make sense because when properly applied, lean manufacturing will lead to a sense of urgency, stress and discomfort. This problem lies because people do not have the proper mindset that is required for lean manufacturing.

Another problem with lean manufacturing is the immediate customer needs that need to be responded to. This again will create a sense of urgency and that will lead to misunderstandings and discomfort. Employees tend to cover a problem if they are rushed instead of focus on fixing the problem. If you have buffers in the system, it is seen as weak and should be eliminated.

Many people feel that lean manufacturing forces people to change instead of allowing them to do it on their own. It is a necessary part in lean manufacturing to push people beyond their comfort zone in order to obtain results.

Six Sigma

Motorola developed Six Sigma to identify and remove defects in the manufacturing process. The Six Sigma methodology uses a series of quality management methods that are based on statistics. Six Sigma creates a unique infrastructure within your organization, assigning certain individuals to have different roles and responsibilities. The methodology follows a karate belt method calling these roles "black belt, green belt, etc." Each step in the Six Sigma project will be assigned to a different group and will be carried out following a defined sequence of steps. The entire process is focused on statistics and your overall goal will be financially set, meaning the end result will include cost reduction or an increase in revenue.

Six Sigma encompasses a wide range of topics. Originally it was designed to improve the manufacturing processes and eliminate defects, but it now defines anything that leads to customer dissatisfaction.

When Bill Smith at Motorola formulated Six Sigma, he was inspired by the Toyota Production System and Lean Manufacturing.

Six Sigma and Lean Manufacturing both believe a business can become successful with the following:

• Reduce process variation through continuous effort to achieve stable and predictable results.
• The manufacturing process has characteristics that can be measured, analyzed, improved and controlled.
• To achieve results, management must believe in the concept and implement a complete cultural change in their organization.

Six Sigma not only implements the above, but it also believes in the following:

• Increasing the emphasis on leadership. Management must be strong and passionate about the program in order to obtain success.
• Having a clear focus will help to measure and achieve quantifiable financial returns.
• The infrastructure of "Champions", "Master Black Belts", "Black Belts", "Green Belts" and "Yellow Belts" will lead, implement, and obtain results from the Six Sigma approach.
• Assumptions and guesswork lead to poor results. By following Six Sigma, a clear commitment to making decisions will come from verifiable data.

Six Sigma came from a field of statistics that is known as process capability studies. These studies are designed to produce defect levels below 3.4 defects per million opportunities.

The different belts in the Six Sigma methodology are as follows:

• Black Belts - they are able to devote all their time to the process.
• Champions - Middle or senior-level executive who sponsors the Six Sigma project and is responsible for the implementation of Six Sigma throughout the company.
• Green belts - these individuals can devote some of their time to Six Sigma.
• Yellow belts - these individuals have been trained in the process, but have not completed a Six Sigma project.

Criticisms Six Sigma

Although Six Sigma is a proven method, it still has critics who disagree that it is successful. Many people will tell you that Six Sigma is simply a marketing ploy. While Six Sigma does draw on tools from other measures, it also represents a modern quality in the context of defects per million opportunities.

Some people will argue that Six Sigma doesn't take enough of a preventative approach to problems. They state that it is more of an appraisal system or a corrective action system. Six Sigma is much more than an appraisal system; it involves extensive training and education to the entire workforce and creates an infrastructure of experts who are involved in numerous projects focusing on quality, timeliness and cost.

Other people have argued that the success of the program depend more on the establishment of the right organizational culture rather than on the program. Unlike other programs, Six Sigma's training takes a look at the importance of a company-wide program mindset instead of individual buy-ins. The methodology must be internalized if it is going to be successful.

Another area where Six Sigma is criticized is for its leadership. Leadership is the key to the success of the complete Six Sigma program. Without the support of leadership at every level, the program will fail. Many critics claim that Six Sigma is simple a "flavor of the month" program and relies heavily on individual support instead of a group implementation.

A few other criticisms of Six Sigma get into the technical aspects like distribution and short-term variability. For each critic of Six Sigma, there are always proponents of the process who can find factual evidence to support their defense.

Lean Manufacturing and Six Sigma

Despite all the critics that are looking for ways to pick apart the 2 methodologies, both systems have been effective and useful for several companies. Because the 2 methodologies go hand-in-hand, many companies have actually combined certain aspect of each method and call it "Lean Six Sigma." Like lean manufacturing and Six Sigma, Lean Six Sigma focuses on creating a "cultural change" within your company.

The results you should see from Lean Six Sigma include:

• Cost reduction
• Improved product quality
• Improved reputation
• Increased customer satisfaction
• Increase in revenue
• Higher volumes of business