Development of CNC incremental forming machine with touch sense and its application to intelligent metal-flow control in sheet metal forming operation

增量拉伸-扩张是金属板被拉伸-扩张以配合在由工具围绕金属板的相对运动形成的工具包络表面上的过程。从无模成形操作的观点来看，渐进成形工艺似乎适合于小批量生产，并且在金属流动控制操作中也被认为是重要的。本文介绍了一种由计算机控制圆柱形刀具运动的触觉式数控渐进成形机的研制，使其模拟陶工轮操作中的手指运动，并将其应用于金属板料拉胀过程中的金属流动智能控制。利用研制的设备对大罐形、深圆柱形等轴对称壳体进行了拉胀成形。以铝、铝合金和铜板为例，研究了不同加工路径对壳体零件应变分布和极限的影响。结果表明，走刀方式对壳体零件的应变分布有影响，金属流动对成形极限和大变形有影响。实验结果表明，金属流动现象可以定性地估计在成形操作过程中的工具和金属板之间的接触信息。因此，所提出的过程中，所开发的机器与触摸传感器是有用的智能金属流动控制在板料成形操作。

An incremental stretch-expandling is a process in which a sheet metal is stretch-expanded to fit on a tool-envelope surface made by relative motion of a tool around the sheet metal. The incremental forming process seems to be suited to small-lot production from viewpoint of a die-less forming operation, and is also thought to be important in metal-flow control operation. This study presents the development of the CNC incremental forming machine with touch sense in which the motion of the cylindrical tool can be controlled by a computer, made to imitate a figer motion in potter's wheel operation, and its application to intelligent metal-flow control in sheet metal stretch-expanding. Various kinds of axisymmetrical shell components, such as bulygy pot-shaped shell and deep cylindrical shell, were stretch-expanded by the developed machine. Effect of tool path schedules on strain distribution and limit in the shell components was examined using aluminum, aluminum alloy and copper sheets. It is found that the tool path schedules has influence on strain distribution in shell components, and the associated metal-flow has influence on the forming limit and large deflection. Experimental results suggest that the metal flow phenomena can be estimate qualitatively by the touch information between the tool and the sheet metal during the forming operation. Therefore, theproposed process by the developed machine with touch sense is useful for intelligent metal-flow control in sheet metal forming operation.