金属板料点压渐进成形试验与模拟研究

Experiment and Simulation on Sheet Metal Incrementally Pressing Forming

板料渐进成形方法是一种钣金零件的柔性制造工艺。为减小连续轨迹渐进成形零件的周向扭曲变形,对逐点挤压板料的渐进成形方式(点压渐进成形是利用成形工具头沿零件的等高线逐点顶压板料而成形零件的一种渐进成形方法)进行研究。建立根据零件尺寸计算点压渐进成形过程中压下量、压点间距与压点位置等的关系式;分析点压渐进成形的零件周向扭曲变形较小的原因,是因为在成形过程中板料主要受成形工具轴向的挤压,材料周向流动较少;建立影响零件表面质量的各压点变形区的相交度与成形参数间的计算关系,相交度越大零件表面质量越好。通过试验与有限元模拟对锥台型试件的点压渐进成形与连续轨迹渐进成形进行对比分析。试验与模拟结果表明,点压渐进成形是一种有效的钣金零件柔性成形方法,所成形试件的周向变形较小,零件成形精度较高,模拟结果与试验相符。

Incremental sheet metal forming is a class of flexible sheet metal forming methods.In order to reduce the circumferential distortion of parts by incrementally forming with continuous trajectories,an incrementally pressing forming（IPF） process is proposed,in which a part is made by having a small punch with hemispherical tip discretely point-to-point press contours（trajectories） of increasing depth.In IPF processes the vertical displacements of tool,distances of adjacent pressing points and positions of each pressing point are calculated on the geometric data of parts.The smaller circumferential distortion of IPF is due to the less material circumferential flow for the forming tool pressing the sheet axially.The intersections of each deformation zone on pressing point are calculated from forming parameters.And the bigger intersections bring about better surface quality of parts.Comparative analyses on the IPF and the incremental forming with continuous trajectories are performed on experiments and simulation.The experimental and simulation results show that IPF is an effective flexible sheet metal forming method,having smaller circumferential distortion and high forming accuracy of the formed part.And the simulation results match the tests.