Abstract

Various approaches have been attempted by researchers to break through the limitation of axisymmetric shape in metal spinning. In this study, a synchronous multipass spinning method for offset blanks is proposed. The motion of the roller and the rotation of the mandrel are synchronized to achieve asymmetric shapes. The roller trajectory is represented by a set of scattered data which contains the axial position of the roller, the radial position of the roller, and the rotational angle of the mandrel. Conventional spinning for offset blanks is also conducted in comparison with synchronous spinning. The geometries of the products with different offset values λ are examined. The axial distribution of wall thickness varies at different circumferential positions of the product due to the oblique shape. The thickness increases from the short side to the long side of the product. A larger offset value λ results in a larger product diameter due to the springback of the material. Forming limits in terms of roller feed ratio f, offset value λ, blank thickness t₀, blank diameter D, and the number of passes are investigated. Both fracture and wrinkling occur in the experiments. Due to the oblique shape, wrinkling tends to occur during the first several passes on the long side of the flange, and fracture tends to occur during the last several passes on the long side of the product. The experiments are more likely to succeed when a small offset ratio λ, a small blank diameter D, a small feed ratio f, or a large blank thickness t₀ is used. Compared with synchronous spinning, the difference between the axial thickness distributions on both sides of the product is smaller in conventional spinning due to the uniform feed ratio. In terms of forming limits, conventional spinning has a slightly better performance.

中文翻译：

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非对称纺丝用于毛坯

摘要

研究人员已经尝试了各种方法来突破金属旋转中轴对称形状的局限性。在这项研究中，提出了一种同步多道次毛坯坯的纺丝方法。辊子的运动和心轴的旋转同步以实现不对称形状。滚子的轨迹由一组分散的数据表示，这些数据包含滚子的轴向位置，滚子的径向位置以及心轴的旋转角度。与同步纺丝相比，还进行了胶印毛坯的常规纺丝。具有不同偏移值λ的产品的几何形状被检查。由于倾斜形状，壁厚的轴向分布在产品的不同圆周位置处变化。厚度从产品的短边到长边增加。较大的偏移值λ由于材料的回弹而导致较大的产品直径。关于辊进给比f，偏移值λ，毛坯厚度t ₀，毛坯直径D的成型极限，并对通过次数进行调查。在实验中断裂和起皱都发生。由于倾斜的形状，在凸缘的长边的前几次通过过程中往往会发生皱纹，而在产品的长边的最后几次通过过程中往往会发生断裂。当偏置比λ小，毛坯直径D小，进给比f小或毛坯厚度t ₀大时，实验更有可能成功用来。与同步纺丝相比，由于均匀的进料比，在常规纺丝中产品两侧轴向厚度分布之间的差异较小。在成形极限方面，常规纺丝的性能稍好。