Six sigma and lean manufacturing are utilized as improvement tools to improve the business. This improvement can take many forms, such as increased business, reduced costs, and improved cycle times or service.
Although lean six sigma projects can be utilized to improve any aspect of a business, it is important to assess the needs from an overall view. Some lean six sigma projects take many months to complete, and it is critical for the time to be utilized wisely. A team of 3-4 six sigma black belts and lean experts can consume of lot of labor and time, and it is critical to have a payback worth the effort.
Lean Six Sigma projects normally follow the DMAIC (Define-Measure-Analyze-Improve-Control) model utilized by six sigma projects. Although the Define phase is the least technical, it warrants all the time necessary to ensure the right projects are selected. For example, if a business has high scrap and costs with a product, it may appear it would be a good candidate for a project. However, it the product is declining due to other factors in the market, a project to develop or design new products might be worthy of consideration.
The Define phase must be fact based. The team should have full knowledge of the objectives and mission of the business, and be empowered to determine the correct projects. Too often, projects are selected on emotion and the power of individuals, which is detrimental to the business and the lean six sigma initiative.
One way of determining which projects to select is based on prioritization techniques. Six sigma black belts are trained to utilize the tools of 7M, prioritization matrix, and cause and effects analysis to determine which projects should have high priority.
Once the project is selected, the project must be thoroughly defined. Along with the definition, the objective should be stated and quantified. For example, the objective could be to “reduce material cost from 40% to 36% for a yearly savings of $618,000.
The measurement utilizes either six sigma or lean tools. Six sigma often utilizes statistics tools such as histograms, ANOVA (analysis of variance), flow charts, process maps, FMEA (failure mode and effects analysis. Lean tools used for measurement include value stream mapping, OEE (overall equipment effectiveness), time studies, methods and flow analysis.
During the Analyze phase, the “bottom line” is determined. In the example above, the Analyze phase might determine that 60% of the material is below 37% and two products average 73% when scrap rates are included. Six sigma tools such as hypothesis testing and brainstorming could be utilized, as well as the lean tools used in the measurement phase. When the project is more “lean” based, the measurement and analysis are often combined.
Once the problem has been determined, it is time for the Improve phase. Six sigma utilizes tools such as DOE (Design of Experiments), while lean often opts for the PDCA (Plan-Do-Check-Act) approach.
The greatest benefit of a lean six sigma approach, is the “tool kit” available during the Improve phase. The entire set of lean tools could be utilized in the improve phase, such as 5S, kaizen, SMED, OEE, value stream mapping, line balance, pull systems, and many others.
Once the solution has been implemented, control must be applied to ensure the improvement is sustained. Six sigma control charts are often utilized, as well as the lean tool of standardized operations.
When lean manufacturing and six sigma are combined, the result is a more robust set of tools. This enables the practice of solving problems using tools, rather than trying to fit a certain tool set to a problem.
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Date Published :
Dec 17 2007