나사 전조공정 해석모델에 제안 및 화산 모양의 변형형상의 예측

In this paper, three-dimensional finite element analysis of screw rolling process of a 12 point flange head bolt is conducted using a rigid-plastic finite element method based metal forming simulator AFDEX 3D. An analysis model is proposed to carry out detailed simulation of thread formation, especially prediction of volcano shape crest. The model is composed of a slice of material, two artificial symmetric planes, and two tapered or flat thread rolling dies. It is applied to a thread rolling process of the 12 point flange bolt with multi-thread and small pitch and depth and the formation of thread including the volcano shape crest is revealed in detail.