PRACTICAL APPLICATION OF PLANETARY CONICAL ROLLING

管的减薄过程是在没有滑动摩擦的情况下完成的，滑动摩擦是传统减薄中造成磨损和断裂的主要原因。在此过程中，多个滚子围绕圆锥体旋转，同时围绕它们各自的轴线旋转。“行星圆锥轧制”工艺被称为PCR。该工艺具有以下优点：（1）辊由轴支撑，不受侧向力，（2）轴的直径与产品内径几乎相同，（3）轴的刚性高，产品精度高，（4）辊子倾斜度不允许辊子与物料之间在径向上滑动。结果表明，该工艺可获得厚度减薄率大于0.89的镜面外表面。为了利用这些特性，通过使材料流入模具上的凹部中来形成具有表面特征的产品。考虑到其实际用途，选择螺纹作为表面特征。成形的螺纹具有优异的质量，但是当涉及到薄壁管时，通过常规的轧制方法成形是困难的。本方法检查形成薄壁管。结果表明，通过进给速度控制径向压力，可以获得较高的填充率。PCR螺纹成形成功的主要原因是PCR的一步一步递增过程填充了凹部。

The process of tube ironing is done without sliding friction which is the main cause for galling and breakage in conventional ironing. In this process a number of rollers rotate around the cone while revolving around their respective axis. The process "Planetary Conical Rolling" is termed PCR.This process has the following advantages : (1) rollers are supported by a shaft being free of lateral force, (2) the diameter of the shaft is almost the same as the inner diameter of the product, (3) high rigidity of the shaft results in high accuracy of products, (4) rollers inclination does not allow slide between roller and material in the radial direction. The results show this process can produce thickness reduction larger than 0.89 with mirror-finished outer surface. In order to make use of these characteristics, products having surface features were formed by flowing material into a concave on a die. A thread was chosen as the surface feature under the consideration of its practical uses. A formed thread has an excellent quality, but when it comes to thin tubes, forming by conventional rolling methods is difficult. The present method examine forming thin tubes. The results show that a higher filling rate of a material into the concave can be obtained by a higher radial pressure which is controlled by the feed speed. The main reason for the successful thread formation by PCR is that the concave is filled by a step by step incremental process of the PCR.