Six Sigma

(Lean) Six Sigma is presented as a breakthrough management strategy to improve cost, inventory and lead time. The six sigma implementation is done by the DMAIC improvement process. (Define, Measure, Analyze, Improve and Control). To understand what implementing Six Sigma means some facts about the first company to apply six sigma: Motorola.

From: The vision of Six Sigma : Mikel Harry

• In 1979 Motorola established that "their quality stinks".
• In 1981 they established a training center and set their quality should improve by a factor of 10 in 1986.
• In 1982 they implemented SPC
• In 1984 they implemented design of experiments
• In 1987 they adopted six sigma approach.
• In 1987 2,4% of the corporate payroll was used for training and 40 % was devoted to quality tools and techniques
• Employees get 150 hours of training about quality techniques in 3 years

What we see from the facts is that implementing six sigma or SPC is a long term project with high commitment from top management and large investments. The tools used to implement six sigma and the approach to implement SPC are the same. If you implement SPC properly you need to establish targets for improvement, you have to apply FMEA, MSA, Process capability analysis, experimental design etc.

To understand which tools and techniques will work in which production situation you have to have knowledge about Total Productive Maintenance (TPM), Lean Manufacturing and Theory of constraints (TOC).

How does a Six Sigma implementation benefit from DataLyzer Spectrum

If you implement six sigma properly you will also implement a good SPC system and a good SPC system will support the different functions of the organization. The statistical tools used during six sigma implementation are standard available in a good SPC system.

Most companies use Minitab during the implementation and when they reach the control phase they start to think about implementing a SPC system. In the mean time they have lost a lot of time gathering datasets and training people in the use of Minitab which will never use Minitab anymore after the SPC system is implemented. So we strongly advocate selecting a good SPC system during the start of the implementation and using the SPC system to make all required analysis. For advanced analysis you can have your black belt use Minitab and you have to make sure the datasets from your SPC system can quickly be imported in Minitab.

Six Sigma Calculator

In Six Sigma the quality of the process is indicated by the sigma number. If the sigma of a process is 6 it indicates that the process has 3.4 defects per million opportunities. The sigma number can be calculated based on the process average, the standard deviation and the specifications. For attribute processes the sigma number can be calculated based on the percentage of defects. With the calculation of the sigma number of a process a prerequisite is that the process has some stability and is more or less in control.

In SPC Wizard you can get the sigma number and test for stability and control. To get an indication of the sigma number of a process we offer a free calculator. You can download the free calculator here.

In SPC Wizard you can test a hypothesis if 2 data sets are different by using the F and t test directly on 2 data sets. We also offer a free F and t test calculator where you can enter the parameters of a data set. Click here to download the free F and t test calculator.