Research On Incremental Forming Of Aluminum Alloy Sheets For Automobiles

With the development of modern science and technology,incremental forming technology with diversified,personalized and rapid performance has emerged as the times require,and is widely used in automotive,aerospace,marine,biomedical devices and other fields.This new,flexible sheet metal forming technology can form complex parts that cannot be realized by conventional processes without the need for a mold or a simple mold,and is suitable for trial production and individual production of new products.In this paper,the typical grades 6061 and 5182 of the 6-series and 5-series aluminum alloys used in the automotive industry are selected for the incremental forming research.The orthogonal experiment method was used to investigate the influence of process parameters on the forming properties of 6061 and 5182,then optimize the process parameters through the variable angle cone cup experiment and the forming limit angle.Process parameter selection in the experiment: Z-axis feed rate,feed rate,tool head diameter,lubrication method.Through range analysis and analysis of variance,the results show,The order of influence of the four process parameters on the forming performance of the 6061 aluminum alloy sheet is the tool head diameter,lubrication mode,feed rate and Z-axis feed amount,however the tool head diameter is a significant factor;The order of influence of the four process parameters on the forming performance of the 5182 aluminum alloy sheet is the tool head diameter,the Z-axis feed amount,the lubrication method and the feed rate,but they are not significant factors.Furthermore,the influence of the incremental forming on the forming properties and forming quality of aluminum alloys for automobiles was investigated by using the friction stir incremental forming experiment.The results show that for the two kinds of aluminum alloys,the forming properties of aluminum alloy sheets for automobiles continue to decrease with the increase of the rotational speed,but the appropriate increase of the rotational speed is beneficial to the improvement of the surface quality.Then,using the multi-directional hammering incremental forming technology,the influence of the hammering angle on the forming properties and forming quality of the two aluminum alloys was investigated,and the optimal combination of process parameters was obtained.The results show that the forming properties of 6061 and 5182 aluminum alloys are positively correlated with the hammering angle,and the forming quality is negatively correlated with the hammering angle.Then,two new tool trajectory-driven hammering incremental forming methods—semi-elliptical trajectory and parabolic trajectory incremental forming—are proposed,and the feasibility of the method and the influence of parameters on the forming performance are verified.In addition,the forming limit diagrams of the two aluminum alloys under different incremental forming conditions were obtained by the arc groove experiment method,and the influence of the incremental forming method on the forming limit curve was compared and analyzed.Finally,based on the numerical simulation and the incremental forming limit diagram,the general incremental forming process of the rear floor reinforcement of the automobile is predicted.The parts were formed by different incremental forming methods,and the effects of different incremental forming methods on the surface quality and forming precision of the formed parts were compared and analyzed.