The Effect of Loading Path on Forming Results in Multi-Gripper Flexible Stretch Forming

2014 ◽  
Vol 538 ◽  
pp. 108-112 ◽  
Author(s):  
You Wang ◽  
Ming Zhe Li ◽  
Hong Wei Liu
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Spherical Surface ◽  
Local Strain ◽  
Loading Path ◽  
Flow State ◽  
Stretch Forming ◽  
Forming Process ◽  
Loading Paths ◽  
Flexible Forming Process

Multi-gripper flexible stretch forming (MGFSF) is a recent technological innovation of sheet metal flexible forming process. Straight jaws in traditional stretch forming machine are replaced by a pair of opposed clamping mechanisms which can move relative to each other. Taking the case of forming a sheet metal into spherical surface by stretching the sheet in two opposite directions, the finite element models of MGFSF under various loading paths were established and the effects on stretch amount, strain and thickness of the simulated parts were analyzed comparatively. It is founded that compared to the horizontal-tilting (HT) and horizontal-vertical (HV) loading paths, the horizontal-tilting-vertical (HTV) loading path would result in more uniform stretch amount, strain and thickness distributions also with lower strain and thickness reduction, which improves the forming quality significantly. Finite element simulations also revealed that the material flow state in the transition zone can be improved effectively and the local strain concentration can be greatly suppressed with reasonable loading path, which would decrease the possibility of material failure.

scholarly journals The Effect of Swinging Ball Heads with Different Arrangements in Multi-Point Stretch-Forming Process

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 337 ◽  
Author(s):  
Jian Xing ◽  
Yan-yan Cheng ◽  
Zhuo Yi
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Sheet Metal ◽  
Strain Distribution ◽  
Finite Element Models ◽  
Stretch Forming ◽  
Forming Process ◽  
Forming Quality ◽  
Staggered Arrangement ◽  
Simulation Results

To improve the effect of multi-point stretch forming of sheet metal, it is proposed in this paper to replace a fixed ball head with a swinging ball head. According to the multi-point dies with different arrangements, this research establishes finite element models of the following stretch forming, i.e., fixed ball heads with conventional arrangement, swinging ball heads with conventional arrangement, swinging ball heads with declining staggered arrangement, and swinging ball heads with parallel staggered arrangement, and then numerical simulation is performed. The simulation results show that by replacing a fixed ball head with a swinging ball head, the surface indentation of the part formed was effectively suppressed, the stress and tension strain distribution of the part formed was improved, and the forming quality was improved; the thickness of the elastic pad was reduced, the springback was reduced and the forming accuracy was improved; and when the ball head was applied to a multi-point die with staggered arrangement, a better forming result was achieved, where the best forming result was achieved in combining the swinging ball heads with the multi-point die with a parallel staggered arrangement. Forming experiments were carried out, and the experimental results were consistent with the trend of numerical simulation results, which verified the correctness of the numerical simulation.

Study of Multi-Roll Stretch Forming Process Using Different Clamps

2010 ◽  
Vol 44-47 ◽  
pp. 2752-2756 ◽  
Author(s):  
Hao Han Zhang ◽  
Ming Zhe Li ◽  
Wen Zhi Fu ◽  
Zhi Qing Hu
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Opposite Direction ◽  
Critical Value ◽  
Finite Element Simulations ◽  
Stretch Forming ◽  
Forming Process ◽  
Wave Type ◽  
Tooth Type ◽  
Formed Part

Multi-Roll Stretch Forming process is a new flexible process which is used in forming hyperbolic-degree surface pieces. A series of finite element simulations and experiments have done for the process of forming saddle-shaped parts using two kinds of clamps named Tooth-type clamp and Wave-type clamp. The results show that Wave-type clamp can control the stretching force at an appropriate value. When the stretching force exceeds a critical value, the sheet metal can flow to the opposite direction of Stretch Forming as to maintain that stretching force. The formed part using Wave-type clamp has a better quality than the parts formed using Tooth-type clamp.

A New Stretch-Forming Process Based on Loading at Discrete Points and its Numerical Investigation

2013 ◽  
Vol 423-426 ◽  
pp. 737-740
Author(s):  
Zhong Yi Cai ◽  
Mi Wang ◽  
Chao Jie Che
Keyword(s):  
Sheet Metal ◽  
Three Dimensional ◽  
Discrete Point ◽  
Stretch Forming ◽  
Sheet Metal Part ◽  
Metal Part ◽  
Forming Process ◽  
Loading Trajectory ◽  
New Process ◽  
Forming Defects

A new stretch-forming process based on discretely loading for three-dimensional sheet metal part is proposed and numerically investigated. The gripping jaw in traditional stretch-forming process is replaced by the discrete array of loading units, and the stretching load is applied at discrete points on the two ends of sheet metal. By controlling the loading trajectory at the each discrete point, an optimal stretch-forming process can be realized. The numerical results on the new stretch-forming process of a saddle-shaped sheet metal part show that the distribution of the deformation on the formed surface of new process is more uniform than that of traditional stretch-forming, and the forming defects can be avoided and better forming quality will be obtained.

Flexible Stretch Forming Technology for Sheet Metal Based on Discrete-Gripper and Multi-Point Die

2014 ◽  
Vol 556-562 ◽  
pp. 460-463 ◽  
Author(s):  
Xue Chen ◽  
Ming Zhe Li ◽  
Wen Hua Liu ◽  
Zhi Qiang Hou
Keyword(s):  
Sheet Metal ◽  
Experimental Results ◽  
Shape Error ◽  
Stretch Forming ◽  
Forming Process ◽  
Structural Composition ◽  
Forming Technology ◽  
Working Principle ◽  
Material Utilization

To solve the problem of low material utilization in traditional stretch forming process, a flexible stretch forming method was proposed, which can be realized by interaction of the multi-point stretch forming die with discrete-gripper stretch forming machine. The principle and characteristics of sheet metal flexible stretch forming technology was introduced, structural composition and working principle of the multi-point stretch forming die and discrete-gripper stretch forming machine were expounded, and the technology experiments was carried out with a self-designed flexible stretch forming technology equipment for sheet metal. The experimental results indicate that structure of multi-point stretch forming die and discrete-gripper stretch forming machine are reasonable, and flexible stretch forming technology can be realized by above-mentioned die and machine, stretch forming parts has a good quality and its shape error can satisfy requirements of production.

Research on the Finite Element Simulation of the Laser Shock Forming of TC4 Titanium Alloy

2016 ◽  
Vol 693 ◽  
pp. 1121-1128 ◽  
Author(s):  
Guo He Li ◽  
David Mbukwa ◽  
Wei Zhao
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Laser Energy ◽  
Sheet Thickness ◽  
High Amplitude ◽  
Laser Spot ◽  
Laser Shock ◽  
Forming Process ◽  
Element Analysis ◽  
Laser Shock Forming

laser shock forming, which combines the metal forming and material modification, is a non-mode, flexible forming new technology using laser-induced force effect of high amplitude shock waves to obtain the plastic deformation of sheet metal. in this paper, the simulation of laser shock forming process of tc4 sheet metal was carried out through the commercial finite element analysis software abaqus. the influence of the sheet thickness, laser energy, constraints aperture and laser spot spacing on the sheet metal deformation are investigated. the results show that: with the increase of sheet thickness, the deformation range of sheet decreases, and the amplitude of deformation decreases firstly and then increases. the deformation increases linearly with the increase of laser energy. the larger boundary constraint aperture leads to the larger deformation of sheet metal. there are no obvious influence on the forming accuracy when an opposite laser spot spacing is adopted. therefore, under the condition of meeting the accuracy requirement, for improving the efficiency, adopting a certain laser spot spacing to finish the forming should be considered.

Forming and springback prediction in press brake air bending combining finite element analysis and neural networks

2018 ◽  
Vol 53 (8) ◽  
pp. 584-601 ◽  
Author(s):  
Sara S Miranda ◽  
Manuel R Barbosa ◽  
Abel D Santos ◽  
J Bessa Pacheco ◽  
Rui L Amaral
Keyword(s):  
Neural Networks ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Sheet Metal ◽  
Computer Numerical Control ◽  
Numerical Control ◽  
Forming Process ◽  
Element Analysis ◽  
Air Bending ◽  
Springback Prediction

Press brake air bending, a process of obtaining products by sheet metal forming, can be considered at first sight a simple geometric problem. However the accuracy of the obtained geometries involves the combination of multiple parameters directly associated with the tools and the processing parameters, as well as with the sheet metal materials and dimensions. The main topic herein presented deals with the capability of predicting the punch displacement process parameter that enables the product to be accurately shaped to a desired bending angle, in press brake air bending. In our approach, it is considered separately the forming process and the elastic recovery (i.e. the springback effect). Current solutions in press brake numerical control (computer numerical control) are normally configured by analytical models developed from geometrical analysis and including correcting factors. In our approach, it is proposed to combine the use of a learning tool, artificial neural networks, with a simulation and data generation tool (finite element analysis). This combination enables modeling the complex nonlinear behavior of the forming process and springback effect, including the validation of results obtained. A developed model taking into account different process parameters and tool geometries allow extending the range of applications with practical interest in industry. The final solution is compatible with its incorporation in a computer numerical control press brake controller. It was concluded that, using this methodology, it is possible to predict efficient and accurate final geometries after bending, being also a step forward to a “first time right” solution. In addition, the developed models, methodologies and obtained results were validated by comparison with experimental tests.

Based on the Finite Element Software ANSYS/LS-DYNA Metal Plate Covering Parts Forming Process Simulation and Optimization Research

2014 ◽  
Vol 912-914 ◽  
pp. 589-592
Author(s):  
Jin Ling Wang
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Metal Plate ◽  
Von Mises Stress ◽  
Skilled Workers ◽  
Forming Process ◽  
Simulation And Optimization ◽  
Finite Element Software ◽  
Stamping Process ◽  
Von Mises

The design of cold punching mould CAD/CAM and the combination of CAE analysis can advance analysis of stamping process program, eventually get ideal stamping parameters, realize design automation, save resources and reduce dependence on experience, reduce the demand for skilled workers. This paper, by using nonlinear dynamic finite element software ANSYS/ls-dyna continuous function, simulation of sheet metal forming process and unloading plate deformation, forming process, at any time throughout the von mises stress nephogram should rebound and strain values and unloading plate material as a result, analysis help us better understand the changes of the internal material sheet metal stamping process.

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