The effect of micro-drill bit’s helicoid symmetry to the micro-drill bit’s rupture

In the course of micro drilling, there are many facts effecting drill bit’s life. Such as micro-drill bit’s diameter, corebit’s diameter, the material and manufacture process of micro-drill bit, the helicoid of micro-drill bit. In this paper, it gives a description how the helicoid’s symmetry effects the micro-drill bit’s rupture in the micro-drilling. On the base of predecessor’s research, the paper states the micro-drill bit’s rupture in the course of micro drilling, because of micro-drill bit’s helicoid symmetry. Simultaneously, propose the method to avoid the drill bit’s rupture and the best means of producing micro-drill bit.