Novel stretch-bending process for metal plate laser thermoforming

Abstract

The invention provides a method for achieving laser bending metal plate forming through a pre-stretch-bending method. Resilience can be reduced to a large extent, and then the bending angle of a plateis increased. The method comprises the steps that firstly, a formed workpiece is fixed to a three-dimensional numerical control platform, one end of the workpiece is fixed through a clamp, and a stretch bending device firstly applies longitudinal tension and then applies transverse pressure to the other free end of the workpiece; and then the upper surface of the plate is heated in a scanned modeby using laser, finally, after the hating area of the plate is completely cooled, the stretch bending device is removed, and the transverse pressure and the longitudinal tension are relieved. A largenumber of literatures prove that the stress state inside the plate can be changed under bending force, more tangential pressure stress generated on the inner side of a neutral layer of the laser heated area is converted into tensile stress, the whole cross section of the plate is under the action of the tensile stress in the tangential direction, and after relieving, resilience of inner-layer fibers and outer-layer fibers counteract each other so that the resilience can be greatly reduced, and then the bending angle of the plate is increased; and the method is suitable for forming of high-hardness, high-brittleness and difficult-to-deform and medium-thickness plate materials, and has a great application prospect in the fields of aerospace, medical treatment and automobile manufacturing.

Description

technical field [0001] The invention relates to a method for forming a laser-bent metal sheet by using a pre-stretch bending method, which belongs to the technical field of mechanical manufacturing and can be applied to rapid bending and orthopedic processing of a small-batch or difficult-to-form metal sheet. [0002] technical background [0003] Laser bending under pre-pressure is a new type of processing technology proposed on the basis of the original laser bending. A certain elastic deformation is applied to the workpiece through the mold, and then the laser is used to scan the area where the elastic deformation is concentrated. Due to the high temperature of the laser, the yield strength of this area is reduced, thereby increasing its plastic deformation ability, and transforming more elastic deformation into plastic deformation. In the case of using a simple mold, in addition to the traditional excellent characteristics, laser bending forming under pre-pressure has fou...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the problems of large springback and small bending angle in laser thermoforming of metal sheets under preload, this paper proposes a new method-stretch bending method: that is, in the process of traditional laser sheet bending under preload, generally applying Lateral preload, while the stretch bending method applies longitudinal tension while applying lateral preload to change the stress distribution in the deformation zone to reduce springback and increase the bending angle of the sheet

Images