TRIMMING METHOD

摘要

PROBLEM TO BE SOLVED: To surely lessen the change rates of characteristics of a circuit board in to an increase in trimming length so as to finely adjust the circuit board in characteristics by a method wherein a trimming operation switches from a trimming line to a following trimming line at a point of time when the measured characteristic of the circuit board mounted with trimmed parts reaches switching characteristics. SOLUTION: The four trimming lines of a trimmed part 1 are previously set in position and trimming length T0 . Then, the switching characteristics of a circuit board which serves as a reference value at which a trimming line switches to a following trimming line at a stage just before the measured characteristic of a circuit board reaches prescribed characteristics and a permissible maximum characteristic change rate of the measured characteristics of the circuit board to serve as a reference value at which a trimming line switches to a following trimming line at a stage just before the measured characteristic of a circuit board reaches prescribed characteristics are previously set. The switch of a trimming line is carried out basing on the two kinds of switching characteristics at the last trimming line but one.