The Reducing Methods Research Of Unexpected Deformations In Laser Bending

As a non-mold, non-contact and new flexible sheet metal forming method, Laser bending offers many advantages such as high precision and easy control, so it has great potential in fields as aerospace, microelectronics and medical application. But there is a problem in this technology, the unexpected distortions that called edge effects exit in the forming process, coming with the expected deformation simultaneously, so the research of reducing the edge effects should be carried out to promote the application of the laser forming technology.Under the support of the project of natural science foundation, this paper discusses the research status and trend of the edge effects, establishes a model to predict the edge effects accurately. Based on this model, the mechanism of the edge effects is uncovered. And then two kinds of the reducing methods are proposed, by analyzing the simulation results and comparison of the simulation and experiments, the model and the reducing methods are verified, the forming accuracy is improved greatly, the main contents of this paper are as follow.Firstly, the paper defines the edge effects completely and gives the corresponding measurement methods. By reasonable simplification, a model based on elastic-plastic mechanics theory is established. Through the analysis of the model, the mechanism of the edge effects is uncovered and the core factor of edge effect is found out.Secondly, the paper establishes a finite element model using the software ANSYS to simulate the laser bending process. By analysis the temperature, deformation fields of the simulation, study the relationship between the edge effects and the temperature, constraint condition. In order to increase the efficiency of the simulation, the paper proposes a shell finite element model, by comparison of the two models' accuracy and efficiency, the optimized new model is proofed to be valid.Thirdly, the paper presents threes methods to reduce the edge effects based on the mechanism. The methods are variation velocity, varying constraint and comprehensive scanning. The simulations and experiments are conducted to predict and verify the effectiveness of these methods. Experimental results show that the comprehensive scanning method is the best strategy to reduce the edge effects, and can increase the accuracy of the laser bending greatly.Finally, the paper summarizes all the done work and views the study direction in the future.