How do you interpret the results of a gauge R&R study in Six Sigma?

A Gauge R&R study estimates variation in a measurement system from repeatability (same operator, same part, same gauge) and reproducibility (different operators, same part, same gauge). Total variation includes part variability. The study quantifies these variations, revealing their contribution to overall measurement error.

In LSS interpreting a Gauge R&R study is important when we have to evaluate the reliability of the measurement system. The assessment will focus on ensuring that a significant portion of variability in measurements is linked to the actual process, indicating a dependable measurement system. By analyzing operator influence (reproducibility) & equipment variability (repeatability), the goal will always be to achieve low variability among operators & minimal differences within the same operator's measurements. A successful study guides improvement efforts, pointing areas for enhancement in the measurement system & facilitating accurate decision-making based on reliable data, ultimately supporting more precise and informed process improvements.

Gage R&R study is a variable MSA study used to check the precision of the measurement system. It helps us to check the presence of and measure repeatability and reproducibility errors in a single study to reduce the time taken to conduct both of these studies separately. Repeatability error occurs when there is a difference in measurement results when the measurement is repeated by the same appraiser on the same object. The main source of variation here is gage(i.e. Equipment). Hence called as "Gage" repeatability (Equipment Variation). Reproducibility error occurs when the measurement is repeated on the same object using the same measuring equipment but by different appraisers (inspectors). It is also called as Appraiser Variation (AV).

O estudo de R&R é uma técnica utilizada para avaliar a precisão e a confiabilidade de um sistema de medição. O objetivo principal do R&R é determinar quanto da variação total em um conjunto de medições é devido à variação do sistema de medição em si, ou seja a "repetibilidade"(Relacionado com o instrumento de medição), e quanto é devido à variação entre diferentes operadores ou medições repetidas, ou "reprodutibilidade"(Relacionado com o método utilizado para a medição).

Calculate the % Contribution to Total Variation Determine the contribution of each component (repeatability and reproducibility) to the total variation in measurements. This helps identify which component contributes the most to the measurement variability. Evaluate the %R&R (Repeatability and Reproducibility) Calculate the %R&R as a percentage of the total variability. A common benchmark is to aim for %R&R to be less than 30% of the tolerance or specification limit. If %R&R is too high, it indicates that the measurement system is not capable of providing accurate and consistent measurements.

Un estudio de R&R de medición en Six Sigma evalúa la repetibilidad y reproducibilidad de un sistema de medición. Es fundamental cuando quiero asegurarme de que los datos que obtengo son precisos y consistentes. Por ejemplo, si mido una pieza en una línea de producción, quiero saber si varios operadores obtienen resultados similares (reproducibilidad) y si el mismo operador puede repetir la medición con precisión (repetibilidad). Así, garantizo que el sistema de medición no introduce variabilidad indebida.

In my view, interpreting a Gauge R&R study involves a systematic approach. Calculate repeatability and reproducibility, assess %R&R and %Tolerance against thresholds, analyze ANOVA results, and use control charts for visual assessment. Evaluate bias, and linearity, and conduct Attribute Agreement Analysis for subjective assessments. Implement improvements and document results for ongoing reliability. This ensures a robust measurement system, providing accurate data for effective decision-making and continuous improvement. It's about systematically enhancing measurement reliability for quality excellence.

A Gauge R&R study evaluates the variability in a measurement system by assessing repeatability (variation when the same operator measures the same part repeatedly) and reproducibility (variation between different operators measuring the same part). It quantifies these factors alongside part variation to determine their contribution to overall measurement error, ensuring measurement reliability.

For a gauge R&R study, choose a diverse part sample, and select qualified operators. Each operator measures parts multiple times with the same gauge. Record data, calculate averages and ranges, then analyze using statistical software or a spreadsheet tool for ANOVA or Gage R&R analysis to assess measurement system variation.

- Take 10 parts, 1 measuring instrument and 3 appraisers - Each appraiser will measure these parts 3 times (at different times while maintaining the measurement result non-traceable to the appraisers)

ara realizar un estudio de R&R, selecciono varias muestras representativas del proceso y defino a los operadores que realizarán las mediciones. Luego, cada operador mide las piezas varias veces, registrando los resultados. Posteriormente, analizo los datos utilizando herramientas estadísticas, como el Análisis de Varianza (ANOVA). Esto me permite cuantificar el porcentaje de variación atribuible al sistema de medición frente a la variabilidad inherente del proceso.

Key metrics include: % Contribution (should be < 1%) = It shows the variation coming from the Measurement System, as a percentage of the Total Variation Observed. It accounts for both sources of variation: Repeatability and Reproducibility. % Study Variation (should be < 10%) = It shows the Measurement System standard deviation, as a percentage of the Total Standard Deviation of the Variation Observed. % Tolerance (should be < 10%) = It shows the variation coming from the Measurement System, as a percentage of the Tolerance (USL – LSL). It accounts for both sources of variation: Repeatability and Reproducibility. A low % suggests that the measurement error has little impact on the correct identification of defective process outputs.

Al interpretar un estudio de R&R, me enfoco en el porcentaje de la variabilidad del sistema de medición respecto al total. Si el sistema contribuye con menos del 10% de la variabilidad, es adecuado. Si el porcentaje es mayor al 30%, el sistema es inaceptable. Por ejemplo, si el R&R muestra un 8% de variabilidad, sé que mi medición es confiable y no afecta significativamente el control del proceso.

Acceptability Criteria: Gauge R&R results are typically expressed as a percentage of the total process variation. A rule of thumb is that a Gauge R&R below 10% indicates an acceptable measurement system, 10-30% requires judgment based on the criticality of the measurement and potential for improvement, and above 30% is considered unacceptable, necessitating immediate improvement actions. Detailed Metrics Analysis: Dive deeper into specifics, such as the percentage of variation due to repeatability, reproducibility, and the actual parts being measured. Understanding these components can help identify specific areas of weakness, whether they relate more to the equipment used or the operators' techniques.

Number of Distinct Categories (NDC): This metric helps understand the measurement system's ability to differentiate between parts. An NDC value that is too low suggests that the measurement system may not be sensitive enough to detect important differences between part measurements.

Setting Up Control Charts: Use data from your Gauge R&R study or ongoing process measurements to establish control limits, mean lines, and other relevant statistics on your chart. Monitoring for Signals: Regularly review the control charts for patterns such as runs, trends, or cycles that deviate from statistical control. These could indicate changes in the process or issues with the measurement system itself. Taking Action: When the control chart indicates an out-of-control condition, it's crucial to investigate and identify the root cause. This could involve further analysis of the measurement system, process adjustments, or both.

Interpreting the results of a Gauge R&R study in Six Sigma involves understanding the measurement system's capability and reliability. In hard disk manufacturing, I conducted a Gauge R&R study to assess the accuracy and consistency of thickness measurements on disk substrates. By collecting data from multiple operators and replicating measurements across different production runs, I quantified the sources of variation due to equipment (repeatability) and operators (reproducibility). This analysis allowed me to calculate metrics like %R&R (percentage of total variation from repeatability and reproducibility) and gauge capability ratios. The results guided us in improving measurement techniques & ensuring reliable substrate thickness control.

Calibration and Maintenance:Ensure that all measurement instruments are regularly calibrated and maintained according to the manufacturer's specifications or industry standards. Operator Training:Enhance the skills and consistency of operators through targeted training on measurement techniques and best practices. Standardization:Develop and enforce standard operating procedures for measurement tasks to reduce variability introduced by different operators or measurement methods. Continuous Improvement:Use the findings from Gauge R&R studies and control chart analyses as a basis for ongoing improvement efforts.This may involve upgrading equipment, refining measurement methods,or other actions aimed at reducing measurement system variability.