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--- articles:soot [2025/07/26 20:22] – [What does this mean?] rrandall
+++ articles:soot [2025/07/26 21:48] (current) – [What does this mean?] rrandall
@@ Line 19: / Line 19: @@
 **Rule (a):** \\
 The Measuring and Test Equipment (M&TE) out-of-tolerance condition exceeds 25% of the product tolerance (the maximum acceptable level of deviation from a product’s specification, measurements or standards). \\
+<wrap em>This SOOT criteria focuses on the Accuracy Ratio as it relates to the product... without consideration to the accuracy of the measuring device.</wrap>
 __Example:__ \\
@@ Line 49: / Line 51: @@
 **Rule (b):** \\
 The Measuring and Test Equipment (M&TE) error is greater than twice the calibration tolerance when product tolerance isn't known. \\
+<wrap em>This SOOT criteria focuses on the Accuracy Ratio as it relates to the measuring device... without consideration to the tolerances associated with the product.</wrap>
 __Example:__ \\
-Keeping with the above example, suppose your measuring device has a calibration tolerance of ±0.5 mm (meaning the device could be off by ±0.5 mm). \\
+Keeping with the above example, suppose your measuring device has a calibration tolerance of ±0.5 mm (meaning the device could be off by ±0.5 mm). This provides a 4:1 Accuracy Ratio with the produce tolerance being measured.\\
-Twice the calibration tolerance = 2 × 0.5 mm = 1.0 mm \\
+Twice the calibration tolerance = 2 × 0.5 mm = ±1.0 mm \\
 __Calibration of Measuring Device__ \\
-Assume that the measuring device was calibrated at 100.0 mm and found to read 99.3 mm (0.7 mm low).
+Assume that the measuring device was calibrated at 100.0 mm and found to read 98.9 mm (1.1 mm low).
-This means the device understates its measurements by 0.7 mm (since 100.0 mm - 99.3 mm = 0.7 mm).
-Bias: -0.7 mm (the device's readings are 0.7 mm less than the actual measurement).
-__Measurements__ \\
-Since the measuring device has a tolerance of ±0.5 mm, in a worst possible scenario, even with a measuring device found in tolerance, the part could actually be read
-When taking a measurement, the measuring device reads: 100.2 mm
-However, the "actual" measured value must include this bias:  **Actual = Displayed Value + Bias**
-This means: 100.2 mm + 0.7 mm = 100.9 mm
+This means the measuring device error was found to be greater than twice the calibration tolerance.
+Conclusion: \\
+This somewhat arbitrary approach toward defining a SOOT condition has little to do with determining the IMPACT of the Out-Of-Tolerance (OOT) condition. \\
-Conclusion:
+If we know the product tolerance, and determine that it had been a 4:1 Accuracy Ration, then halving the calibration accuracy of the measuring device (which is what doubling the error does), means that a ≤2:1 Accuracy Ratio exists. That would indeed be significant. \\
-.1 mm > 102 mm, so the part is out of tolerance
-This means that whatever reading your measuring device displays has a -1.1 mm bias (indicating the actual measurement value is +1.1 mm greater than indicated).
+<wrap em>HOWEVER</wrap>, what if the measuring device was 10 times more accurate than the product tolerance? \\
-So if your device displays a measurement of 101.0 mm, it's true reading would be 102.1 mm (101.0 + 1.1 mm)! \\
+In that case, an error of twice the calibration tolerance would have simply reduced the Accuracy Ratio from 10:1 to 5:1. Since an Accuracy Ration would have still been greater than 4:1, the impact would have been insignificant.
-Since the bias (1.1 mm) this is more than twice the calibration tolerance (± 1.0 mm) this is a SOOT condition.
 ===== Why was this added to their requirements? =====