There are times when Six Sigma proves an excellent methodology for the elimination of defects. Sometimes defects are understood from VOC or VOS. These may be relevant from the point of view of the business, but there may be some defects that may not be noticed.
For example, if there are delays within a process, then by speeding up the process, the defect may be eliminated. However, this may be at the cost of quality if it is not given consideration. Here is where Lean can be useful by using the seven wastes theory. Additionally, defects will be reduced when the problem is solved.
The Six Sigma DMAIC method relies on the analysis of the problem and may not be able to provide solutions to real life problems. Thus, if you combine the two, Lean and Six Sigma you may have good solutions to rely on.
Lean Tools in Six Sigma Projects
Defects based on Lean wastes are rejects, movement, inventory, over processing, over production, transportation and waiting for the next step. In addition, it provides 5S, value stream mapping and error proofing, which in conjunction with Six Sigma can help sort out real life issues easily.
Let us take the example of the assembly of printed wiring board components (PWB). The process of assembling these components is a very complicated one and faces the critical problem of failure at the final product test.
The assembly, being complicated, is prone to defects and errors that could have caused further delays in shipping and rework. The Lean Six Sigma team in this case should focus on understanding the PWB components assembly area. If this is done, they will find three areas of errors, Manual insertion, automated insertion as well as semi-automated insertion.
Kitting errors, wherein all components are not provided as a common kit, can be identified. Other errors may also occur, such as layout of the manual insertion workstation and positioning the axial lead parts on the automatic insertion machine. The problems can be prioritized and further action taken.
The Lean way to problem solving can help overcome this situation so that improvements can be realized for a longer period. To achieve great results, Lean methodologies and Six Sigma phases can be combined.
By considering and implementing brainstorming sessions and the seven wastes in the Define phase of DMAIC, teams find it easier to define the problem area and develop creative solutions to the problem. In the Measure phase, teams can use Lean tools such as value-added to non-value added ratios, CT over Takt time and so on - and collect and measure the data related to the problem area.
In the Analyze phase, value stream mapping and the reframing matrix can be effectively used to look at the problem from different view points and prioritize those which need immediate attention.
In the Improve phase, the usage of 5S and other tools like the visual factory concept can help in sorting out problem areas and finding a different approach, if other approaches have been rejected. In the Control phase, error proofing is extremely useful to put controls in place to avoid errors in the first place.
Lean and Six Sigma provide creative solutions to solving real-life issues by precisely pointing out the errors and providing different ways to eliminate them. The data- driven approach of Six Sigma and the Lean way can work wonders for businesses.
About the Author
Tony Jacowski is a quality analyst for The MBA Journal. Aveta Solution's Six Sigma Online offers online six sigma training and certification classes for six sigma professionals including, lean six sigma, black belts, green belts, and yellow belts.