基于单刃-圆锥面刀具的三维整体外翅片成形机理

采用单刃-圆锥面刀具加工三维整体外翅片管,研究了翅片成形过程及圆锥面半径对翅片成形的影响,分析了翅片微观形貌的形成机理及加工参数对翅片形貌的影响.翅片成形机理在于单刃-圆锥面刀具切削时能将工件表层金属与基体分离但并不去除,被分离的金属在圆锥面的挤压下形成翅片.翅片成形过程可分为犁切分离、滑动挤压和成翅3个阶段,较大的圆弧半径有利于翅片的成形.翅片顶部有一条贯穿整个翅片的微裂缝,使翅片在微观上成为双翅片;随着犁切深度的增加,翅片厚度增加;随着进给量的增大,翅片间距增加.

Forming Mechanism of 3D Integral Outside Fins Fabricated by Tool with Single Edge and Cone Extruding Face

3D integral outside finned tubes were fabricated by using a tool with single edge and cone extruding face,and the forming process of fins as well as its dependence on the radius of cone extruding face was investigated.Then,the forming mechanism of fin micromorphology and the influences of cutting parameters on fin micromorphology were analyzed.It is found that,in the forming process,the surface metal material of workpiece only splits rather than removes from the workpiece body,and the split chips are extruded into fins by the cone extruding face.The forming process of fins can be divided into three stages including splitting,sliding and fins forming,and big radius of cone extruding face contributes to the forming.Moreover,it is indicated that the microcrack to intersect the whole fin at the top makes the fin turn into double fins microscopically,and that the thickness of fins increases with the cutting depth and the pitch of fins increases with the feed.