Countermeasures to suppress polygonal deformation of machined hole with irregular pitch reamer

Abstract

Reaming is a finishing process for expanding the pilot hole and improving the accuracy of roundness. In machining using regular teeth pitch reamer, a polygonal deformation phenomenon occurs in the machined hole due to self-excited vibration caused by time delay, which causes a problem of deterioration in product accuracy. In the previous studies, the authors clarify the generation mechanism of the polygonal deformation and examined the suppressive effect of the irregular tooth pitch reamers theoretically. The irregular tooth pitch reamers are available commercially and have been found to have improved roundness compared to regular tooth pitch reamers. However, the optimum design of the irregular pitch reamers has not yet been discussed. In this paper, the authors theoretically and experimentally discuss the optimum design of the irregular pitch reamers.