Research On Processing Of Fully Automatic Vertical Bar Straightening Machine

Bars produced by free forging are prone to produce varying degrees of bending deformation,which will affect the straightness of the bar directly and thereby lower the accuracy of subsequent machining.Therefore,it is necessary to straighten the bent bar before machining in order to improve the quality of subsequent machined products.At present,in the aspect of straightening equipment,domestic manufacturers mostly observe the bending shape of bar manually,and then straighten the bar on press machine by virtue of experience.With a poor working environment,manual straightening method relies on long-term experience of the operator,which also has a low straightening precision and efficiency.Foreign straightening equipment has been greatly improved in automation,measurement accuracy,straightening efficiency and other aspects,however,it is difficult for most manufacturers to import the equipment on account of high cost.In this dissertation,the theory of automatic straightening processing of bar was deeply studied based on the elastoplastic,on the basis of analysis of the existing literature and research.In addition,the straightening process of bar was simulated and analyzed with finite element method.The main research contents of this dissertation are as follows:(1)The main component modules of vertical bar straightening machine were analyzed,the function and principle of each component module of the straightening machine was expounded in detail,also the working flow and technical parameters of automatic straightening machine were provided in this dissertation.(2)The relationship between stress and strain in the bending process of bar was analyzed based on the elastoplastic theory during the transverse force bending process.The theoretical method for calculating the straightening stroke of single radian planar bending form of bar was derived based on the bilinear hardening material model.And the straightening processing decision method of multi-radian planar bending form and spatial bending form of bar was studied on the basis of the above.(3)The simulation experiment of the straightening process of the established bar model was carried out by using the finite element analysis software ABAQUS,and the stress of the bar after the springback,the deviation degree of the geometric center axis from the reference axis,and the flatness of bar were analyzed.In this dissertation,the correctness and feasibility of the theoretical calculation method of straightening processing were obtained by establishing a finite element model of bending bar and simulating the automatic straightening process,which could provide the technological parameter basis for automatic straightening.