Abstract: Based on ultrasonic vibration-assisted mode, high-frequency impacting tests with diamond indenter at different amplitudes on AlTiN coating of cutting tool are carried out. The microstructure and morphology are obtained by scanning electron microscopy (SEM) and 3D profiler. The failure mechanism of coating under impact is analyzed. The high frequency fatigue property of the coating is analyzed. The results show that: lateral crack could be seen under impact test; the maximum tensile stress occurs close the edge of the contact zone of impact center; AlTiN coating is easy to emerge the fatigue damage under the high-frequency impact loading, and the adhesion strength of the coating and substrate interface affects the impact fatigue strength of cutting tool coating.
Abstract: Due to the problems that the rolling force of seamless steel tube during tandem rolling process is affected by many factors, the calculation is complex and the accuracy is not enough. In order to improve the rolling force calculation accuracy of the tandem rolling mill, analyze the metal flow, stress distribution rules and cross section deformation characteristics during the rolling process of seamless steel tube, calculation of the rolling force was divided into the reduced-diameter area and the reduction of wall area, and a new calculation method was proposed, which concerns the rolling force in reduced-diameter area related to the material yield stress, friction coefficient and the crushing stress of the tube, while the rolling force in the reduction of wall area is only related to the material yield stress and the friction coefficient. The results show that the calculated rolling force is in agreement with the measured values with errors less than ±10%. The model satisfies the actual conditions and is applicable to engineering application.
Abstract: In this paper, the mathematical model of "S" - shaped cutting-edge curve is optimized, and the position and orientation of the grinding wheel of the first and second flank of the ball end milling cutter are calculated, The correctness of the algorithm is verified by VERICUT simulation.
Abstract: Due to the influence of rolling force fluctuations, tube size changes and material uniformity and other factors, vibration and other phenomenon inevitably occur in the rolling process of tandem rolling mill. This vibration has a great impact on the dynamic stability of the mill and rolling reduction, and will significantly reduce the dimensional accuracy and surface quality of seamless steel pipe. In this paper, the non-linear finite element software ABAQUS is used to simulate the rolling process of seamless steel pipe. First, rolling force of the first frame with the maximum rolling force of PQF rolling mill is calculated. The reliability of rolling force calculated by the finite element method is verified by the test experiment. The dynamic response analysis of the roll is carried out to obtain the dynamic response curve of the roll in the rolling state and to provide technical support for the rolling schedule with the calculated rolling force being the load.
Abstract: The instantaneous uncut chip thickness is an important parameter in the study of milling force model. By analyzing the real tooth trajectory in milling process, accurate instantaneous uncut chip thickness can be obtained to solve the complex transcendental equation. Traditional chip thickness models always simplify the tooth trajectory to get approximate solution. A new instantaneous uncut chip thickness model is proposed in this paper. Based on real tooth trajectory of general end milling cutter, a Taylor's series is used to approximate the involved infinitesimal variable in the transcendental equation, which results in an explicit expression for practical application of the uncut chip thickness with higher accuracy compared to the traditional model.
Abstract: In this paper, the GC cup truing technology on resin bond diamond grinding wheel is studied, and the parameters of truing the diamond grinding wheel process are optimized. Also the contour accuracy and microscopic topography of the diamond grinding wheel are analyzed quantitatively. Besides, the method of evaluating the dressing effect of diamond grinding with the roughness of grinding wheel is proposed.