在实际工业生产中,许多构件的表面是由双曲面构成的,因此,研究复杂型面激光热成形加工工艺规划策略具有重要的现实意义。然而,作为一种无模成形工艺,激光加热路径和目标型面没有直接联系,这增加了工艺规划的难度。为了实现双曲率面构件的高精度激光热成形,基于交叉加热与板材预弯曲对塑性应变场影响的研究,提出一种新的工艺规划策略。该方法基于板材成形所需要的应变场,分别建立平板和预弯曲板工艺参数与残余塑性应变基本关系数据库以及上下表面应变比基本关系数据库,采用上下表面分别加热进行双曲率面工艺规划。实验结果表明,利用该加工策略,激光热成形面与目标曲面形状基本吻合。

In engineering applications,some components are composed of doubly curved shapes. It is of significance for investigations on processing strategy of complicated doubly curved surface in laser forming. However,as a dieless forming technique,laser heating paths are not necessarily directly related with the desired shape,which raises the degree of difficulty for process planning. To acquire high accurate shape with doubly curved in laser forming,a new design approach is proposed to determine path planning and process parameters based on the studies of cross heating and pre-bend in this paper. Firstly,a strain field required to obtain a desired shape from a planar shape is obtained. Secondly,the heating paths are planned in the top and the bottom surface separately. Thirdly,the basic relationship databases of the flat and curved plate between process parameters and residual plastic strain and between process parameters and strain ratio of the top and bottom surfaces are built,respectively. Finally,the heating condition is determined according to the required strain field and the basic relationship databases. The experimental result based on the above process strategy shows that the laser forming shape is approximately consistent with the desirable shape.