Research On Roll Bending Of Profile For Variable Curvatures

Variable curvature roll bending forming is a common aviation enterprise profile bending forming process, has the processing time, low processing cost, less convenient roller replacement, suitable for various profiles of small batch bend forming. But as a result of roll bending belongs to no mold forming, side stretch forming process, the other side compression, exist within the material is elastic deformation and plastic deformation, cause the forming process is a large amount of rebound, it is difficult to control the forming precision, at the same time, the roll forming equipment online size detection accuracy is not high, control system, lead to roll bending forming and die forming process compared with the relatively low accuracy, cannot satisfy the requirement of the aviation, space curved parts precision, to improve the variable curvature profile roll bending forming process control precision, this paper has carried on the research work of the following several aspects:First analyze the roll profile bending elastic-plastic theory, deduce the general expression under the condition of roll bending springback radius, on this basis, the introduction of profile of neutral layer concept, solving the profile expression of neutral layer of roll bending radius, the expressions in general springback radius formula, it is concluded that the final roll bending springback radius expression.Second roll bending motion control coordinate expression is established, in roll forming process of tooling design, introducing the gap between the roller and profiles, effectively avoid bruises and scratches on the surface of the von berg systeme; At the same time to reverse the process of sheet metal forming were analyzed, and the study of variable curvature roll forming technology, using sectional forming method, theory of variable curvature roll bending forming.And then established the finite element simulation model of roll forming, the forming roller is obtained after the profiles of the whole stress and strain and the cross section, the change rule of stress and strain analysis was studied for the material springback simulation method, no mode method is adopted to accomplish roll bending springback simulation, the springback amount of profile is defined, and find the corresponding springback radius measurement method, the analysis of the roll bending springback simulation results, different roll bending radius profile springback amount of simulated values were compared with the theoretical value, and analyzes the friction factor, wheel clamping force, wheel speed, roll bending radius and other factor’s influence on the material springback radius, through the definition of wheel movement, has realized the change of curvature profile of roll bending forming simulation.