1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
Dismiss Notice
You must be a registered member in order to post messages and view/download attached files in this forum.
Click here to register.

Clause 7.1.5.1.1 - Measurement System Analysis

Discussion in 'IATF 16949:2016 - Automotive Quality Systems' started by bkirch, May 21, 2025.

  1. bkirch

    bkirch Active Member

    Joined:
    Jun 24, 2016
    Messages:
    94
    Likes Received:
    20
    Trophy Points:
    7
    On the IATF website, they publish FAQ's. there is one regarding IATF clause 7.1.5.1.1 regarding Measurement System Analysis. The published question was "Are MSA studies required for each instrument or device?" The answer was "No. A complete statistical study on each single piece of equipment is not required. Instruments with the same characteristics (e.g. measurement range, resolution, repeatability,
    etc.) can be grouped and a sample instrument (representative of the gauge family) can be
    used for the statistical study."

    My question is does this answer also apply to attribute gages such as plug gages. We use a lot of plug gages and they are a variety of different sizes. Currently we group all plug gages into their own "family of gages". Is this correct, per the expectations of this clause(7.1.5.1.1)?
     
    bkirch, May 21, 2025
    #1
  2. Andy Nichols

    Andy Nichols Moderator Staff Member

    Joined:
    Jul 30, 2015
    Messages:
    5,451
    Likes Received:
    2,703
    Trophy Points:
    112
    Location:
    In the "Rust Belt"
    I believe it is.
     
    Andy Nichols, May 21, 2025
    #2
  3. Miner

    Miner Moderator Staff Member

    Joined:
    Jul 30, 2015
    Messages:
    665
    Likes Received:
    572
    Trophy Points:
    92
    Location:
    Greater Milwaukee USA
    This above and beyond what is called out in IATF but is based on my experience in creating gauge families. Read my blog on Intro to MSA of Continuous Data - Part 10: Creating gauge families Note that while the article focuses on continuous gauges, most of the concepts still apply to attribute gages as well, namely that the families need to be based on three things: 1) similar gages, 2) similar product features, and 3) similar tolerances. IATF specifies the first but not the last two. You will likely get different study results if you used a pin to check a hole diameter, the minor diameter of a threaded hole, the radius of a slot, or the radius of a fillet, hence requirement 2). Obviously the tightness of the tolerances will have an impact driving 3).
     
    Miner, May 21, 2025
    #3
  4. bkirch

    bkirch Active Member

    Joined:
    Jun 24, 2016
    Messages:
    94
    Likes Received:
    20
    Trophy Points:
    7
    Thank you Miner. Still on the subject of measurement system analysis, IATF 16949 states that for measurement system analysis "The analytical methods and acceptance criteria used shall conform to those in reference manuals on measurement systems analysis." Although it doesn't specifically mention it, I think most people would reference the AIAG MSA reference manual. My question is that this manual mentions bias, linearity, and stability studies. Since they are mentioned in the manual, should I assume that they are required or just recommended?
     
    bkirch, May 22, 2025
    #4
  5. Miner

    Miner Moderator Staff Member

    Joined:
    Jul 30, 2015
    Messages:
    665
    Likes Received:
    572
    Trophy Points:
    92
    Location:
    Greater Milwaukee USA
    IATF lists three reference manuals in “ANNEX B: Bibliography – supplemental automotive” which can be followed.
    • AIAG – measurement system analysis (MSA)
    • ANFIA – AQ 024 MSA Measurement system analysis
    • VDA – Volume 5 “Capability of Measuring System”
    Regarding bias, linearity and stability, that most likely will depend on the auditor that you get. My recommendation is that bias and linearity be covered in your calibration program for all gages. This is just good practice. For stability, I would perform a risk assessment as to whether the gage would be adversely affected by changes in ambient conditions.
     
    Miner, May 22, 2025
    #5
    Bev D likes this.
  6. Andy Nichols

    Andy Nichols Moderator Staff Member

    Joined:
    Jul 30, 2015
    Messages:
    5,451
    Likes Received:
    2,703
    Trophy Points:
    112
    Location:
    In the "Rust Belt"
    I agree that it's good practice to conduct - appropriate to the device - linearity, bias and stability studies. Some equipment doesn't need all three, but then some (IATF) auditors don't know enough to know that fact, so tread carefully if you don't do all three!
     
    Andy Nichols, May 23, 2025
    #6