非圆截面线电极高精度电解切割基础研究

Literature review indicates that the essence of precision electrochemical cutting is to realize the stable machining with a constant gap. In this project, the method of precision electrochemical cutting with a wire electrode of non-circular sections is proposed. Swirling flow generated by the rotation and the reciprocating rectilinear movement of this wire electrode is expected to accelerate the electrolytic refreshment and the products removal. Hence, a stable electrolytic environment is formed for precision machining. This method is of significant meaning to fabricate turbo mortise structures in aero-engines, precision gear, etc. which are made of difficult to cut materials and demanded in rigid surface quality. Electrolytic swirling flow generated by the rotation and the reciprocating rectilinear movement in a micro-scale gap will be investigated. The machining gap distribution in precision electrochemical cutting will be calculated. Key techniques, such as reciprocating rectilinear movement of large strake, high precision and high speed, geometry optimization of non-circular sections, in-situ fabrication of wire electrodes, process status detection and control will be broken through. Experiments will be conducted to explore the relations between the mechanisms and the process rules, which is fundamental to acknowledge this precision electrochemical cutting method.

高精度电解切割的关键在于实现恒定的等间隙加工。本项目提出采用非圆截面线电极进行电解切割，通过线电极旋转运动和往复直线运动的有益叠加扰动微尺度间隙内电解液流动，促进电解加工产物的排出，形成有利于高精度电解切割的稳定加工环境。本项目研究对于航空发动机榫头/榫槽、精密齿轮等难加工材料高表面质量要求直纹面零件的精密制造具有重要意义。本项目以非圆截面线电极旋转运动、往复直线运动条件下微尺度间隙内电解液流动状态分析为基础；以电解切割加工间隙分布研究为主线；以大行程、高精度、高速往复直线运动实现，线电极几何轮廓优化设计，非圆截面线电极在线制备，电解切割加工状态特征提取与控制为桥梁；建立加工机理、关键技术与工艺规律之间的联系，为非圆截面线电极高精度电解切割研究奠定基础。

提高狭长间隙内电解液的更新速度，加快加工产物的排出，是提高大厚度直纹面结构线电极电解切割加工精度和加工效率的关键。本项目提出非圆截面线电极电解切割加工方法：通过改变线电极表面轮廓形状（螺旋、削边、肋状），利用线电极的机械运动（高速旋转、大幅值往复运动）产生变化的电场和流场进行电解切割加工，扰动整个加工间隙内电解液，使其产生强对流运动，促进加工产物排出和电解液更新。本项目建立了超精密电解切割试验平台，实现了线电极高速旋转、大行程高精度往复直线运动；制备出多种类型的非圆截面线电极（螺旋状线电极、削边电极、肋状线电极）；阐明了微螺旋电极高速旋转、削边电极高速旋转、肋状线电极大幅值往复运动强化传质的机理，试验显著提高了电解切割加工效率；研究了络合剂、有机盐溶液对于提高电解切割加工定域性和表面质量的效果；实现了304不锈钢、GH4169、铝合金、钛合金Ti6Al4V等材料微结构的高精度加工；成功加工出20mm厚不锈钢材料榫头/榫槽试件，表面粗糙度Ra约为0.652µm，加工表面无重铸层、微裂纹等缺陷。本项目共计发表学术论文8篇，其中SCI收录5篇；获授权发明专利2项；培养研究生5名。