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PPAP submissions/TS: Are all MSA Studies required?

Discussion in 'Gage R&R and MSA - Measurement Systems Analysis' started by Larry Ricketts, Mar 8, 2016.

  1. Larry Ricketts

    Larry Ricketts Member

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    Question on MSA Requirement. Specifically: Are Gage Linearity, Bias and Stability test a requirement for PPAP submission. Or better yet are they a TS requirement?

    We calibrated most of our own hand tools, calipers, mics, indicators and set up the calibration to use the full range of the gage.

    We also conduct Gage R n R studies on all gages called out on the control plan. My struggle is that I can not find anything specific in the PPAP or MSA manuals that states a requirement for linearity, bias, or stability and at what interval they are to be done.
     
  2. Golfman25

    Golfman25 Well-Known Member

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    "My struggle is that I can not find anything specific in the PPAP or MSA manuals that states a requirement for linearity, bias, or stability and at what interval they are to be done."

    That's because there isn't. Common sense generally applies, but we know what happens there.

    Let me guess. Did you have an audit finding because you didn't have bias, linearity and stability?
     
  3. Miner

    Miner Moderator Staff Member

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    This is a good opportunity to apply risk-based decisions. For example, a good calibration process should include linearity measurements. Is it necessary to complete an additional linearity study/ What is the risk given your product and tolerances. If the measurement device is used over a limited range, linearity is of limited impact. Consider stability. Most measurement devices such as calipers or mics are only sensitive to temperature and the impact is only felt at very tight tolerances. Do your product fall into this category? On the other hand, some electronic testers might change readings over time as they heat up. This may not be as big of an issue as the technology has matured, but was a major issue. What is your risk?

    Bottom line, if you can justify that the risk is low, you should be able to document this as a reason to forego performing these analyses, but if the risk is high, you should conduct the studies.
     
    Mark Paul, TheWaeller and Bev D like this.

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