The force on a particle moving along a conical curve under any initial conditions is discussed.

Applying the theorem to conical curve, one can get a new "Butterfly Theorem" which makes up for the deficiencies of the classical one and widens its scope of application.

This paper analyses the geometrical character of curve of edge of form milling cutter, and infers the mathematical equations of curve, The center coordinates of conical button-shaped are evaluated.