Machining Precision according to the Change of Feedrate when Ball Endmilling of Semisphere Shape

볼 엔드밀에 의한 반구 가공시 이송속도 변화에 따른 가공정밀도

Experimental study was conducted for finding the characteristics of machining precision according to the change of feedrate when ball endmilling of semisphere shape. The values of tool deflection and cutting force were measured simultaneously by the systems of eddy-current sensor and dynamometer. The machining precision was analyzed by roundness values, which were deeply relating with tool deflection and forces. the roundness was decreased in down-milling than in up-milling for each feedrate. As the cutting edge is moved to radius direction on the tool path, the tool deflection and the cutting force were seemed to be decreased. As the tool path was moved downward, the values of roundness, cutting force and tool deflection were obtained better ones. When compared the values of roundness, cutting force and tool deflection for different feedrate, the best machining accuracy was obtained at feed rate of 90mm/min in down-milling.