TUNABLE HOLDER FOR BORING BARS

摘要

This paper described a flexible tool holder which acts as a dynamic absorber for a boring bar. By introducing flexibility into the holder (using a notched flexure geometry) and matching its fundamental natural frequency to the first cantilever natural frequency of the boring bar, the holder effectively served as a dynamic absorber for the boring bar. An analytical approach was used to select the nominal holder response for an ISO A10-SCLPR2 NE4 boring bar with a 6:1 length to diameter ratio (15.9 mm diameter). Finite element models were used to refine the design. Components were machined and frequency response function measurements were completed. The dynamic stiffness of the holder-boring bar assembly was compared to the stiffness of the cantilever boring bar alone; Stiffness improvements up to 68% were observed for the holder-boring bar assembly.