Research on monitoring method for thinning spinning process of the ultra-thin-walled cylinder based on the drum shape

Abstract

In order to perceive the state of the process of reverse thinning spinning of the ultra-thin wall tube, a monitoring method based on drum shape is proposed. The method uses the non-uniform rational basis spline curve fitting method based on the moving least squares method to reconstruct the outer contour data of the spinning zone collected by the line laser displacement sensor and extracts the outer contour curve of the drum zone according to the spinning characteristics. Then, the dynamic time warping algorithm is used to analyze the similarity between the current and previous drum curves in order to judge whether the current spinning state is abrupt or not. At the same time, the current spinning state is judged by combining the curvature comb of the drum curve, the number of convex areas of the drum curve, the drum ratio, and the drum change trend. Finally, the drum shape detection and the spinning condition monitoring experiments are carried out. The experimental results show that this method can obtain the outer contour shape of the drum section at one time, and the accuracy is 0.05 mm with respect to the measured value of the three coordinates. The method can realize the visual monitoring of the abrupt change of the spinning process by judging the similarity of the drum curve at the adjacent time under different spinning states. In the state of instability, the curvature comb of the drum curve is discontinuous, the curve is G0 continuous, the drum ratio exceeds the critical drum ratio 2.0, and there is more than one convex region, which realizes the monitoring of spinning state more accurately. The experimental results verify the correctness of the proposed method and prove that the method can be used as a new method to judge the stability of the ultra-thin-walled cylinder spinning process.

Stability of feeding cylinder shell under torsion in pneumo-mechanical spinning machines

“…In this case, the sample can be stretched almost to destruction without significant residual deformations [5].…”

“…When stability is lost under the action of torques, the straightness of the generatrices of the system disappears. The radial interleaving at this position is determined from the formulas, (5) Where the amplitude value is the radial displacement and it is determined from formulas.…”

“…The issue is relevant virtually in all fields of engineering: structures composed of beams can resist by virtue of its geometry. Such structures can be found from large scale, such as bridges and buildings located in seismically active regions to microbeam systems used in modern electronic equipment which is subject to vibration environment [5]. They obtained vibration modes and frequencies of the hyper-elastic membrane by analytical and numerical methods and then reduced the order of the models for noncolinear dynamic analysis, which was achieved by the Galerkin method.…”