The geometric accuracy and surface roughness are mainly affected by th
e flank wear at the minor cutting edge in finish machining. A fuzzy es
timator obtained by a fuzzy inference algorithm with a max-min composi
tion rule to evaluate the minor flank wear length in finish milling is
introduced. The features sensitive to minor flank wear are extracted
from the dispersion analysis of a time series AR model of the feed dir
ectional acceleration of the spindle housing. Linguistic rules for fuz
zy estimation are constructed using these features, and then fuzzy inf
erences are carried out with test data sets under various cutting cond
itions. The proposed system turns out to be effective for estimating m
inor flank wear length, and its mean error is less than 12%.