Some companies decide to implement lean manufacturing, while others believe six sigma is the necessary initiative to improve their business. There is now a growing list of companies combining both methods under the initiative called Lean Six Sigma.



It is a fairly new approach, leaving many companies perplexed with the roadmap to implementation. It's not surprising, since implementing either lean manufacturing or six sigma alone is a daunting task.

Lean manufacturing consists of about 25 major concepts, such as 5s, SMED, Error Proofing, Quality at the Source, Line Balancing, OEE, Kanban, Value Stream Mapping, Cellular Manufacturing, and Standard Operations. Some companies spend a few years implementing these terrific principles into their organization.

Six sigma consists of a 5 phase methodology Define-Measure-Analyze-Improve-Control (DMAIC), utilizing hundreds of tools throughout the phases.

Combine both methods and all of these tools, and it's easy to understand why initiatives fail. Unless the organization has the expertise to handle the implementation and help focus the efforts, the program becomes a shotgun approach and is doomed to fail. Most organizations could not withstand the chaos and prolonged costs without substantial payback.

Both lean manufacturing and six sigma principles are proven to work. Many companies have increased business, reduced costs, increased throughput, and lowered cycle times using both approaches. It only makes sense to utilize every tool available to obtain the maximum improvement possible.

It is critical for companies to let the problem determine the tools that are needed, rather than determine the tool and try and force the use of it.

Some projects are obviously a lean manufacturing initiative. For example, if a machine has a 40 minute setup time and it is the bottleneck, then a SMED project is necessary. It may be part of a kaizen blitz or a simple SMED (single minute exchange of die).

There are clearly other projects which will be primarily a six sigma project. For example, a batch process plant using 12 different ingredients with various processes at different temperatures, speeds, and viscosities, would require a six sigma project to determine the best combination of machines, speeds, and viscosities to obtain maximum results. Some of the six sigma tools used would be statistical analysis, hypothesis testing, design of experiments, and analysis of variance (ANOVA).

There are many other types of projects where both lean manufacturing and six sigma tools would best solve the challenge. For example, suppose a batch processing problem involved the various ingredients, speeds, and temperatures. The best method might be a certain mix of machines, but the best one has a 5 person crew with a 2 hour setup time. It is time for the lean tools to reduce the cost per man hour utilizing OEE (Overall Equipment Effectiveness) tools as well as SMED, and possibly 5S.

A common use of lean tools in a six sigma project is during the Improve phase. The six sigma project Define, Measured, and Analyzed the problem, but a lean tool is necessary to solve it. Another six sigma tool will help Control it. If the company only used one of either six sigma or lean manufacturing tools, the problem may not get solved.

The beauty of six sigma is the methodical approach to opportunities. The advantage of lean manufacturing tools is the speed of implementation. When both tools are combined and used when necessary to solve business opportunities, the best result and greatest payback will be obtained.