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Which SPC chart for tensile testing?

Discussion in 'SPC - Statistical Process Control' started by Trish O'Connell, Jan 30, 2020.

  1. Trish O'Connell

    Trish O'Connell New Member

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    I'm just wondering if anybody knows which SPC chart would best suit a tensile testing application.
    Obviously there is a specified lower limit but there is really no upper limits ( tubing can be as strong as possible but NUST have a minimum strength)
    I'm thinking XmR (ImR) might suit as if there were UCL & LCL they would speak to the stability/predictability of the process producing the tubing..
    However i would welcome any advice...
    Thanx
     
    Trish O'Connell, Jan 30, 2020
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  2. Bev D

    Bev D Moderator Staff Member

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    I would try I, MR first. Assuming tensile testing is only done on 1 unit per sampling period.
    Remember the specification is irrelevant in SPC.

    If you have difficulty you could post your data here and we can take a look.
     
    Bev D, Jan 31, 2020
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    Miner likes this.
  3. Miner

    Miner Moderator Staff Member

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    I would recommend the same. Remember, the purpose of using SPC is to have a stable and predictable process. Even though it may sound desirable to have higher tensile results, it is a sign that your process is no longer stable and therefore is unpredictable. Also, remember that there may be other characteristics that are correlated with tensile strength, and that a higher tensile strength may move those characteristics into an undesirable direction.
     
    Miner, Jan 31, 2020
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