Capability Indices
The calculated sigma value is used to calculate SPC capability indices such as Cp and Cpk. This table lists the settings that can be used to derive capability indices:
| Based On | Description |
|---|---|
| XS | The Capability indices are calculated by estimating sigma values using the mean range of subgroups. |
| XR | The capability indices are calculated by using sigma values derived from the mean of the standard deviations calculated for each subgroup. |
| Unilateral QCI 9310-190 XS | The capability indices are calculated as specified in Honeywell standard (QCI 9310-190), using XS for sigma estimation. This method is suitable for unilateral geometrical characteristics where Target =0. |
| Unilateral QCI 9310-190 XR | The capability indices are calculated as specified in Honeywell standard (QCI 9310-190), using XR for sigma estimation. This method is suitable for unilateral geometrical characteristics where Target =0. |
| Sigma 0 | The capability indices are calculated using the actual sigma value, assuming a normal distribution. |
| PSA Q.54.4000 | The capability indices are calculated as specified in the PSA standard (Q.54.4000). This method is typically applied within the automotive supply chain for the PSA group, specifically regarding geometrical characteristics. |
| Non-Normal (Median) | The capability indices are calculated based on the Davis Bothe’s method. This method is applied in scenarios involving data populations with a known non-normal distribution. The calculation uses the median as the central value and defines the spread by subtracting the minimum from the maximum. |
| CNOMO E41.32.120N | The capability indices are calculated based on the CNOMO standard (E41.32.120N). The CNOMO E41.32.120N method is frequently used in the automotive supply chain for the Renault group, specifically regarding geometric characteristics. |
| CNOMO E41.32.110N | The capability indices are calculated based on the CNOMO standard (E41.32.120N). This method is frequently used in the automotive supply chain for the Renault group, specifically regarding geometric characteristics. |