# Process-capability indices
# Scope: Normal stable process Cp and Cpk from supplied sigma; no stability test.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

upper = 10.2 mm
lower = 9.8 mm
mean = 10.02 mm
sigma = 0.04 mm

cp := (upper-lower)/(6*sigma)
cpk := min(upper-mean,mean-lower)/(3*sigma)

check capability target: cpk >= 1.33

scenario alternative: upper = 8.16 mm