Free-bending process characteristics and forming process design of copper tubular components

2018 ◽  
Vol 96 (9-12) ◽  
pp. 3585-3601 ◽  
Author(s):  
Xunzhong Guo ◽  
Hao Xiong ◽  
Yong Xu ◽  
Yannan Ma ◽  
Ali Abd El-Aty ◽  
...  
2019 ◽  
Vol 949 ◽  
pp. 48-56 ◽  
Author(s):  
Karsten Richter ◽  
Franz Reuther ◽  
Roland Müller

One effect of high influence on the dimensional accuracy during bending is springback. It inevitably occurs due to the elastic proportion in the material behavior. The impact is notably high when producing springs made of ultra-high strength spring strips of the steel grade 1.4310 (X10CrNi18-8). The high yield ratio needed to fulfil the functionalities required during application leads to dimensional inaccuracies that have to be compensated during the production process. This paper reports a simulation-based approach to predict the springback behaviour of ultra-high strength spring strips with tensile strengths TS = 1500-1800 MPa. Based on the results of advanced material testing and modelling, the numerical prediction of the springback behavior of an exemplary bending process (free bending) has been investigated in detail. This helps to obtain deeper knowledge and understanding of the springback phenomenon and to achieve suitable strategies for a more efficient industrial tool and process design while processing ultra-high strength spring strips.


2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Ruixue Zhai ◽  
Pengcheng Fu ◽  
Rui Ma ◽  
Jun Zhao ◽  
Cuiyun Ge

The parts formed by the bending process not only have high precision of appearance dimension but also have good performance. In recent years, enterprises have put forward higher requirements for the forming process and product quality. Therefore, a new method for iterative compensation of bending springback with certain generality is proposed for continuous curvature bending. The purpose of this study is to take curvature as an iterative parameter and make the shape size reach the expected value through the finite compensation. On the basis of establishing this iterative compensation mechanism, the convergence of curvature iteration in the general free bending process is proved. The reliability of the proposed iterative compensation method in the bending process engineering application is verified by combining simulation with experiment. The two materials of 304 stainless steel and ST12 cold rolled steel were studied, and the two-dimensional plane stress-strain model Abaqus cantilever beam was established by using finite element software. The bending forming simulation was carried out based on the above iterative compensation mechanism. Finally, through the bending experiments of four models, the feasibility of the iterative compensation mechanism of curvature in the continuous curvature plane bending process is verified, and different models are selected to clarify that the method has the characteristics of generality, that is, it will greatly improve the flexibility of the bending process in industrial applications without the limitation of material types and mechanical models.


Author(s):  
Yang Li ◽  
Yong-Phil Jeon ◽  
Chung-Gil Kang

Bending behavior occurs in the hot press forming process, resulting in many cases of failure during forming. To address the problem of cracking and improve the formability and mechanical properties of boron steel sheets in the bending process, an experiment has been carried out by using a spring compound bending die. Also, a comparison has been made between the traditional U-bending die and the spring compound bending die with regard to formability. The influence of the parameters for hot press forming such as the heating temperature, punch speed, and die radii on the mechanical properties and microstructure was analyzed by tension testing and metallographic observations.


2021 ◽  
Vol 72 ◽  
pp. 215-226
Author(s):  
Cheng Cheng ◽  
Hao Chen ◽  
Jiaxin Guo ◽  
Xunzhong Guo ◽  
Yuanji Shi

Author(s):  
Qiyang Zuo ◽  
Kai He ◽  
Xiaobing Dang ◽  
Wei Feng ◽  
Ruxu Du

Bending complex curved steel plates for constructing ship hull has long been a challenge in shipbuilding industry. This paper presents a novel incremental bending process to obtain complicated curved steel plates by a series of sequential and layered punches. Taking advantage of this process, the blank plate that is fixed and held by a flexible supporting system can incrementally be bent into the target shape by a press tool along a planned tool path step by step and layer by layer. Acting as a “lower die,” the flexible supporting system can provide flexible and multifunctional supports for the work piece during the forming process, whose four general motion modes are demonstrated in this paper. Meanwhile, the procedures of tool path planning and forming layering are also explained in detail. In addition, aiming at different motion modes of the flexible supporting system, two springback compensation methods are given. Furthermore, according to the forming principle presented in this paper, an original incremental prototype equipment was designed and manufactured, which is mainly composed of a three-axis computer numerical control (CNC) machine, a flexible supporting system, and a three-dimensional (3D) scanning feedback system. A series of forming experiments focusing on a gradual curvature shape were carried out using this prototype to investigate the feasibility and validity of this forming process.


2020 ◽  
Vol 109 (7-8) ◽  
pp. 1789-1799
Author(s):  
Yusen Li ◽  
Andi Li ◽  
Zhenming Yue ◽  
Liangyu Qiu ◽  
Houssem Badreddine ◽  
...  

2008 ◽  
Vol 575-578 ◽  
pp. 186-191
Author(s):  
Jun Zhao ◽  
Chun Jian Su ◽  
Ying Ping Guan

The main problem in bending process of sheet metal is that it is difficult to control bending springback accurately. Springback produced from the unloading of bending makes the shape and size incongruent between bending workpiece and working portion of die. Because the final shape of bending workpiece is related with the whole deformation process, the geometric parameter of die, material performance parameter will have great effect on springback. Therefore, the springback problem is very complicated and the prediction and control of springback is the key to improve the accuracy of bending workpiece. Taking the V free bending of wide sheet as an object of study, the neural networks technology and data acquisition system based on LabVIEW are used to establish intelligent control experiment system for V free bending of wide sheet metal. The control accuracy of system is high and it provides the basis for the realization of intelligent control for V-shape free bending of wide sheet metal in practice in future.


Author(s):  
B Zhou ◽  
X Han ◽  
W Guo ◽  
Z Liu ◽  
S-K Tan

Line heating is an important plate bending process that has been adopted in shipyards for more than 60 years. This paper presents the results of a numerical and experimental study on the residual deformation and stress distribution in the plate forming process using the line heating method. In this paper, a finite element model was used to simulate the heating process, and the model was validated using experimental results. The model was then used to analyze the deformation and stress distributions in the heating and non-heating region. The impact of line heating and sequence of heating on both sides of a steel plate was discussed. The findings of the study show that the compression stress generated help to increase the shrinkage of line heating process. This study presents a valuable reference for similar thermal process.


2014 ◽  
Vol 907 ◽  
pp. 99-112 ◽  
Author(s):  
Jörg Avemann ◽  
Stefan Calmano ◽  
Sebastian Schmitt ◽  
Peter Groche

In forming technology, uncertainty can arouse from fluctuations in demand scenarios on one hand and in properties of semi-finished parts on the other. These technologies are usually characterized by a high productivity in mass production. However, high development efforts and investment costs for processes and machines lead to a rigid product and process spectrum. One approach to encounter these uncertainties is the introduction of flexibility into forming technologies by enlarging the number of degrees of freedom without drastically reducing productivity. The 3D Servo Press fulfils the mentioned requirements by exceeding free ram motion of conventional servo presses by two rotational ram DoFs. The adaptive control system coordinates the machine motion and controls product properties by model-based algorithms. Possibilities of this approach are demonstrated in a free bending process of a heat dissipater, resulting in uniform product quality despite variations in material, sheet thickness and desired geometry.


2020 ◽  
Vol 299 ◽  
pp. 351-357
Author(s):  
Sergey A. Tipalin ◽  
Michael A. Petrov ◽  
Yuriy A. Morgunov

During the bending operation of the thin sheet materials by the punch with the near-to-zero radius the special technological operation should be carried out. It means that the metal sheet obtained a certain thinning value, which is usually done in the form of the channel-concentrator or groove by pre-drawing operation in a cold state. It follows to the pre-straining and strengthening of the material. The authors investigated the strain hardened sheet's area after roll forming process theoretically, and obtained the strain-stress distribution inside the sheet during the bending operation. It was found out that the increase of the prior deformation during pre-straining in the bend layer follows to the increase of the radial and tangential stresses and displacement of the neutral axis inside the blank during bending operation. As a result, the bending moment changes its values depends on the punch radius and strain hardening.


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