Define "new process." If there's no data, there's no basis for calculations. The alternative is to make something up, which is a popular strategy, but not recommended.
Before this gets out of hand, some clarification is in order. First, it's still not clear what austin999 is asking. Do you want an expected value for a new process? Cpk or Ppk expectations are dictated by the customer. Please tell us more about what you want to know.
Rkelly, there is no generally accepted reason to use Ppk rather than Cpk for new processes. A lot depends on how much data is available, and how it's collected, and Ppk is generally described as a "performance" index, not a "preliminary process capability" index.
You can use Cpk if you want to. There's a lot of information on this subject here. Use the search function and you'll find it. Start with the list of links below the posts here on this page.
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