When quality engineers refer to a company has achieved six sigma quality level, they often mention the company has 3.4 defect per million opportunities (3.4 DPMO).
Here is what happened in the process:
Customer provide a Lower Speciation Limit (LSL) and Upper Specification Limit (USL) and Target (Target = (USL+LSL)/2).
When a process is at Six Sigma level, the relationship between the process sigma and (USL-LSL) is “(USL-LSL) = 12*Sigma”
The actual process center shifted from Target to Target+1.5*Sigma.
Use the information above, complete the following questions.
Show how 3.4 DPMO is calculated.
Using the same type of calculation, determine the DPMO for a company that is in the five sigma (where “(USL-LSL)=10*Sigma”) quality level.
If a company is currently at five sigma quality level and has a plan to improve 20% annually, how many years it will take the company to achieve six sigma quality level?