TS Measurement Systems Analysis (MSA) 1 — Questions and Answers
Question 1: What does a Gauge Repeatability and Reproducibility (GR&R) study primarily evaluate?
- The accuracy of the measurement device relative to a reference standard
- The variation attributed to the measurement system compared to total process variation (Correct answer)
- The number of defects produced by a manufacturing process
- The calibration interval required for test equipment
Correct answer: The variation attributed to the measurement system compared to total process variation
A GR&R study quantifies how much of the total observed variation comes from the measurement system itself, separating it from true part-to-part variation.
Question 2: According to AIAG MSA guidelines, what %GRR value indicates a measurement system is generally acceptable?
- Less than 10% (Correct answer)
- Between 10% and 20%
- Between 20% and 30%
- Greater than 30%
Correct answer: Less than 10%
AIAG guidelines state that a %GRR under 10% is generally acceptable, indicating the measurement system contributes minimal variation to the total.
Question 3: In measurement systems analysis, 'repeatability' refers to:
- Variation when different appraisers measure the same part
- Variation when the same appraiser measures the same part multiple times with the same gauge (Correct answer)
- The ability of a gauge to measure across its full range consistently
- The agreement between a gauge reading and the true value
Correct answer: Variation when the same appraiser measures the same part multiple times with the same gauge
Repeatability (equipment variation) measures the variation obtained when one appraiser repeatedly measures the same part with the same gauge under the same conditions.
Question 4: 'Reproducibility' in a GR&R study is best defined as:
- The variation seen when the same part is measured multiple times by the same operator
- The ability of a gauge to return to zero after each measurement
- The variation in measurements when different appraisers measure the same part using the same gauge (Correct answer)
- The difference between the maximum and minimum readings in a dataset
Correct answer: The variation in measurements when different appraisers measure the same part using the same gauge
Reproducibility (appraiser variation) captures the variation introduced when different operators use the same gauge to measure the same part.
Question 5: In MSA, 'bias' is defined as:
- The spread of measurements obtained from repeated readings
- The difference between the observed average measurement and the reference (true) value (Correct answer)
- The variation in gauge accuracy across its measurement range
- The tendency of an appraiser to unconsciously influence measurement results
Correct answer: The difference between the observed average measurement and the reference (true) value
Bias is the systematic error in a measurement system — the difference between the average of repeated measurements and the accepted reference value.
Question 6: What does 'linearity' assess in a measurement system?
- Whether the gauge produces consistent results across repeated trials
- The change in bias across the operating range of the measurement system (Correct answer)
- The ability of the gauge to distinguish between two adjacent part sizes
- The time required for the gauge to stabilize before taking readings
Correct answer: The change in bias across the operating range of the measurement system
Linearity evaluates whether the bias of a measurement system remains constant across its expected operating range.
Question 7: A Type 1 gauge study is used primarily to:
- Evaluate appraiser-to-appraiser variation across multiple operators
- Assess the capability and repeatability of a gauge using one operator and one reference part (Correct answer)
- Determine if a measurement system can distinguish between conforming and nonconforming parts
- Compare two different gauges measuring the same characteristic
Correct answer: Assess the capability and repeatability of a gauge using one operator and one reference part
A Type 1 gauge study uses a single operator and a single reference part measured multiple times to evaluate gauge capability and repeatability alone.
TS Measurement Systems Analysis (MSA) 1
What does a Gauge Repeatability and Reproducibility (GR&R) study primarily evaluate?