Study On Effect Of Forming Stages And Interval Angle On Multi-stage Incremental Forming

Incremental sheet metal forming (ISF) is a new forming process for sheet metal. Itcan form those rapid prototyping and small amount of parts which is financial and savetime. The scope of design for numerical control incremental forming is abroad. Thisforming process do not need dedicated die and its formability and repeatability are fine.It can control the metal flow point-to-point and form the free-form surface withcomplex shape. ISF is fit for the machining of new sample piece of automobile andsanitary fittings which is small amount，multispecies and complex. Therefor, sheet metalincremental forming will bring huge economic value.CNC incremental forming could form the parts with complex shape. It needsmulti-stage incremental forming when the part needs good formability or the angle aretoo wide. The important content is to research how the forming stage n and forminginterval angle α influence the formability of the blank.First, as far as the apply of the ISF technology, a project is planned which usingsingle stage and double stage forming processes to form a automobile panel respectively.Then some numerical simulations and experiments were carried out using sheetincremental forming. last, the simulation results were compared with the experimentalresults. It turned out that the automobile panel could not be formed well using singlestage forming process and when used double stage forming process, the part wasfinished forming well. This result verified the applying importance and researchabilityof multi-stage forming process.Secondly，taking the part with a30°angle of cone as the forming part，a series offorming programme were formulated and there are different forming stage n andinterval angle α in these forming plan. When studying the influence of the formingstage n, the interval angle keep a constant10°and research the part simulation resultswith single-stage, double-stage and three-stage forming processes separately. Whenstudy the influence of interval angle α, there are three group forming processes with5°、10°、15°interval respectively. The results showed that the blank thicknessdistribution were more uniform, the thinnest value and the equivalent strain increasedwith the increasing of forming stage n. Forming stage n has unconspicuous influence onthe part springback. when the forming stage n is constant, the blank formability wasbetter with the decreased of interval angle α. And the α has almost no effect on springback.At last, a series of experiments about the multi-stage incremental forming wereimplemented. The blank thickness and springback of all the formed parts were detectedusing micrometer and HandyScan3D. Then the detect results were compared with thesimulation results and it reach some conclusions about the influences of n and α on thepart formability. The results indicate that the blank thickness thinning decreased and thesurface quality of parts came to be better with the increasing of n. Forming stage n hasunconspicuous influence on the part springback. when the forming stage n is constant,the blank formability was better with the decreased of interval angle α. After theverification of the experiments, the simulation results were agree with the experimentresults, so the simulation results could reflect the actual results.