Extrusion Process with Control of Bend and Twist for Producing Shaped Tubes and Bars without Additional Processes for Cancel of Distortion and Second Forming

笔者开发的动模柔性挤压工艺已应用于汽车空间架和发电机涡轮叶片的成形。结果表明：构建了模具在挤压过程中可连续以固定速度旋转的柔性挤压系统。利用该系统进行了模具倾角两步变化的挤压试验。在适当的冲床速度和模具转速下挤压坯料，得到无形状弯曲缺陷的弯曲产品。结果表明，该挤出系统可有效地用于制造细长、复杂弯曲的产品。提出了一种新工艺，通过由两个以固定角度倾斜的交叉模具组成的孔挤压坯料，以提供具有非对称截面的扭曲产品，如涡轮叶片。利用该工艺进行了矩形和梯形截面的挤压试验。结果表明，随着模孔标准倾角的增大，挤压制品的弯曲度减小。验证了该方法的有效性。针对挤压过程中横截面、曲率和扭转角的变化，设计了具有高柔性的新系统。利用该系统进行了对称和非对称h型棒材的挤压试验。对系统的性能进行了详细的测试。应用该系统可在不更换模具的情况下快速生产各种尺寸的h型弯棒。

The flexible extrusion process with moving dies, which has been developed by the author, is applied to forming of space frames for automobiles and turbine blades for generators. The results are summarized as follows :The flexible extrusion system, in which the die could be continuously rotated at a fixed speed during extrusion, is constructed.The extrusion tests with two-step change in the inclination angle of the die are carried out using the system.The curved products without defects in shape curved are obtained as the billets are extruded at the appropriate punch speed and rotating speed of the dies.It is confirmed that the extrusion system is effectively utilized for manufacturing elongated and complicatedly curved products.The new process, in which the billets are extruded through an aperture composed of two crossed dies inclined at a fixed angle, is proposed to supply twisted products with asymmetric cross sections such as turbine blades. The extrusion tests for rectangular and trapezoidal cross sections are carried out by use of the process. It is clarified that the bend of the extruded product decreases with increasing the standard inclination angle of the die aperture. The validity of the process is confirmed.For varying the cross section, the curvature and the angle of twist during extrusion, the new system with high flexibility is designed.The extrusion tests for symmetric and asymmetric H-type bars are executed using the system.The performance of the system is examined in detail.The H-type curved bars with various dimensions can be promptly produced without changing the dies by applying the system.