유연성이 있는 볼 엔드밀 공구의 처짐 모델과 절삭성에 대한 연구

Abstract

본 연구에서는 비교적 강성이 약한 볼 엔드밀 공구에 있어서 처짐으로 인한 그 가공 특성을 알기 위하여, 변화된 칩 두께 및 처짐 모델로부터 절삭력을 예측하며 또한 절삭력에 의한 공구의 처짐으로 인하여 공구의 플랭크 부위와 공작물간의 발생하 는 간섭 특성을 고찰하고, 이러한 특성이 절삭성과 가공 오차에 미치는 영향을 실험을 통하여 분석하여 본다.

Due to the development of CNC machining centers and CAD/CAM softwares, cutter deflections in ball end milling has become to be a main factor affecting surface errors in the machining of sculptured surface. In this study, machining characteristics with flexible ball end mill cutters were studied with a mechanistic cutting force prediction model for cutter deflections. The basic mechanics for ball end milling process was derived from three dimensional analysis of experimental results obtained from orthogonal metal cutting. This model took into account the changes in chip thickness by the deflections of cutter, and also used the deflections of previous cutting tooth successively. The model was verified through the comparison of measured and predicted cutting forces for different machining conditions. The predicted forces showed more close to the measured forces then the forces predicted in the rigid cutter model. The machining characteristics owing to the deflections of ball end mill were also discussed with experimental results.