Robert Tipton


  • Hi

    +/- 0.005 allows for 0.005 in the X Direction, as well as +/-0.005 in the Y Direction.

    This Equates to a Hypotenuse, at a 45 Degree Angle, of 0.007  (Radius) Times 2 = .014 True Position RFS.

    Not Considering the Tolerance for the MMC, the 0.002 MMC, would be a severe and dramatic reduction of the total tolerance.

    0.002 True Position is…[Read more]

  • Hi –

    The General Rule of Thumb is +/- 25% of the Sample Size.

    Example: Average Sample Size of 100 +/- 25%  =  +/-25,  it is OK to use the same Control Limits.

    If the Sample Size is <=74, or >=126, then use Different Control Limits.

    These different control limits are sometimes referred to as a Manhattan Skyline.

      1 year, 6 months ag…

  • Sigma is the Standard Deviation, not the formula you indicated 1 year, 8 months ago

  • Hello –

    If you have a negative CPk, it means you have at least 50% Failures, assuming the formula is correct.

    The lower the negative CPk, the more Percent failures.

    As an Example;  Negative 1 CPk would be about 99.7% Failures, to the Specification

    Then look at the CP Value.  If CP is positive, you probably only need to adjust the mean (…[Read more]

  • I have done hundreds of leak testers, with no problem

    assure that you have a maximum of 10% gage resolution.

    use normal Gage R & R, with Normal Bell Curves.

    Use SPC with Normal or Pearson Curve

      2 years, 3 months ago

  • Hello –

    I would like to provide some additional insight.

    1.) Assure that the Gage is Acceptable for the measurements.

    1.1) Check Increments and Resolution, Gage Resolution should be less than 10% Resolution, I recommend 5%.

    Example: +/- .010 = Total Tolerance of .020.   Increments to be less than .001 = 5% Resolution.

    1.2) Gage Accuracy,…[Read more]