Investigation on the bar clamping position of a new type of precision cropping system with variable frequency vibration

The purpose of this paper is to obtain the correct clamping position of the bar during the cropping process based on a new type of precision cropping system with variable-frequency vibration. The mathematical model is built by finite-element method and the simulation experiments were designed by means of an orthogonal method. The analytical results show that the diameter D of the bar exerts an influence on the ratio of the maximum tension stress to the maximum shear stress near the notch bottom remarkably. The influence of the length L2 of second-segment bar extending out the clamping die on it can be minimal. The reasonable geometrical parameters of the clamping bar for a segment of bar with definite length to diameter ratio are determined: the proportion of L1 to the diameter D of the bar is 0.3, and the proportion of L2 to D is 0.25. According to the special feature of the obtained cutting surface, a new measurement method is proposed and applied to assess the quality of the cross-section. The theoretical analysis and experiments prove that, by reasonably setting clamping position of the bar, high-quality cross-section can be obtained.