Aiming at the structural characteristic of complex groove, by studying the chip restriction action of geometrical element which is composed of complex groove, the equation of chip restriction action point and the prediction formula of chip - curl directional angle are deduced and the prediction model of complex groove chip up -curl radius and side -curl radius are destablished.

In this paper a new interpolation method for quadratic B-spline curves is proposed so as to fully utilize the degrees of freedom provided by parameterization and knot vector to control the shapes of the interpolation curves intuitively by the tangent constraints on data points.