How many PPM are considered typical for a 2 sigma level?

To understand the number of Parts Per Million (PPM) that corresponds to a 2 sigma level, it's important to grasp the relationship between sigma levels and defect rates in a process. In quality management, a sigma level reflects how well a process is performing in terms of defect avoidance.

At a 2 sigma level, the process has a significant defect rate, indicating that it is far from being optimally efficient. Specifically, a 2 sigma process typically results in approximately 308,770 defects per million opportunities (DPMO). When converted to PPM, this translates to 308,770 PPM, meaning that out of a million produced parts, around 308,770 are expected to be defective.

In summary, the PPM value of 308,770 is indicative of a poorly performing process with a 2 sigma level, which signifies a high likelihood of defects. Other sigma levels have much lower PPM rates, reflecting better process performance and lower defect rates. Thus, 308,770 PPM is the characteristic defect level for a 2 sigma capability.