Research On Roll Forming Process And Software Development Of Four-Roll Bending Machine

Four roll bending machine is widely used in shipbuilding,wind energy collection,civil engineering,mechanical engineering and other fields.However,at present,when forming parts with high precision by four-roll bending machine,operators still need to adjust the position parameters of process rolls repeatedly with experience,so the productivity is low.The rolling equipment manufacturers need to improve the automatic control technology in the process of rolling forming,improve the processing accuracy and efficiency of the plate,and reduce the labor intensity of the workers.In this paper,aiming at the forming quality and production efficiency of the four-roll bending machine,the rolling and bending forming process of the four-roll bending machine is studied,and a set of rolling process database software system is developed.The main contents include:(1)Based on the elastic-plastic theory,the mathematical model of forming radius before and after springback of sheet metal in roll forming is established;based on four kinds of stress-strain relations,the mathematical model of calculating bending moment of sheet metal is derived.(2)Based on the existing theory,the calculation of the relationship between the displacement of the roll and the mechanics of each roll of the four roll rolling machine is deduced;in view of the influence of the curvature center deviation on the displacement of the lower roll during asymmetric rolling,from the mechanical point of view,the relative displacement of the shaft roll is calculated according to the bending moment and the hydraulic pressure of the lower roll,and the calculation method of the displacement of the shaft roll is improved;the calculation error of the improved method is 1.3%,which proves the effectiveness of the improved method.(3)Using the finite element software Abaqus/Explicit to simulate the roll forming process of the four roll rolling machine;combining with the definition of the ovality of seamless steel tube,a method of evaluating the forming quality of the sheet metal is determined,the influence of the width of the sheet metal and the number of the roll bends on the forming radius and quality of the sheet metal is studied,the simulation results show that the forming radius increases with the increase of width,and the ovality decreases with the increase of passes,with the exception of single pass.(4)The effects of plate width and lower roll pressure on the roll forming radius of sheet metal are studied by roll bending experiments;based on the rolling experiments and pre bending experiments,the influence law of the clamping and pre bending direction of the upper and lower rolls on the roll bending forming is studied;The experiments results show that the relative displacement of the lower side roll of the same forming radius decreases with the increase of width and with the decrease of the lower roll pressure,the rolling and pre-bending directions have a great influence on the forming radius.(5)A set of calculation and management software for the rolling and bending process of the four-roll bending machine is developed based on Winform.The structure and modules of the software are described,and the way of data management is discussed.Through the research of the rolling law and the development of the process software,it provides the theoretical and practical reference for the automation and intelligence of the rolling and bending process of the four-roll bending machine.