板料柔性拉边成形与压边成形方式的比较

Comparison on Flexible Blank-drawer and Blank-holder Forming Process for Sheet Metal

柔性拉边成形是在已有冲压成形工艺的基础上结合柔性拉形原理诞生的一种新型板料柔性成形方法。用柔性拉边技术代替传统压边技术,可实现球形件、鞍形件、盒形件、非规则曲面件及带凸台曲面件等三维曲面件的柔性成形。探讨柔性拉边成形原理及工艺,建立柔性拉边成形过程的有限元模型;为验证柔性拉边成形工艺的可行性和通用性,建立鞍形件多点模具成形及带凸台曲面件整体模具成形过程的有限元模型,通过对比分析拉边成形和压边成形方式,研究不同成形方式对板料起皱拉裂缺陷、应力应变分布、流动及回弹情况的影响。结果表明:压边成形时,板料容易产生起皱、拉裂等缺陷,较难得到高质量的成形件;而在相同条件下,采用拉边成形方式所得成形件应力应变分布均匀、回弹小,拉边力抑制起皱、拉裂等缺陷的产生,同时板料流动更均匀。

The principle of flexible blank-drawer forming（FBDF）, a new type flexible forming method, is studied for the first time based on the existing stamping process and the flexible stretch-forming. The flexible blank-drawer forming principle and process are discussed, and the FE model of blank-drawer forming is set up; In order to validate the universal and feasibility of the flexible blank-drawer forming process, numerical simulations on multi-point forming of saddle parts and rigid-die forming of convex-boss panels on blank-holder forming process and blank-drawer forming process with finite element method are done and the effects of blank-holder and blank-drawer on stress, strain, wrinkles, cracks, sheet flow and springback are studied. The results show that sheet metal easily wrinkle and crack in the blank-holder forming; while under the same condition, the blank-drawer forming process can get the parts with even stress, strain distribution and small springback through suppress wrinking and craking.