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1.
Dongwei Ao Xingrong Chu Yang Yang Shuxia Lin Jun Gao 《The International Journal of Advanced Manufacturing Technology》2018,95(9-12):3197-3213
Because the intermediate-stage forming surface and the intermediate-stage forming tool path of the complex shape model are difficult to generate, the existing multi-stage CNC incremental forming takes the regular rotary body model or the square model as the research objects, and all adopt the three-axis CNC incremental forming mode. In this paper, a method for generating the intermediate-stage surface by using a longitude line that can reflect the personality of the surface and the five-axis CNC multi-stage incremental forming tool path was proposed. Firstly, the vertexes of the triangular facets of the STL model are used to generate the longitude lines which can reflect the characteristic of the surface, then the longitude lines are offset according to the multi-stage forming strategy and the characteristics of each surface associated with the longitude lines so that the intermediate-stage longitude lines could be generated, and then the intermediate-stage surfaces are built using the intermediate-stage longitude lines. Finally, the cutter location points of each intermediate stage are obtained by cutting the intermediate-stage surfaces, and the postures of the five-axis CNC pressing tool are determined according to the normal vector of the cutter location points. The case studies show that the proposed method can well generate the five-axis CNC multi-stage incremental forming path for the complex shape sheet metal part. The results of the numerical simulation analysis and forming experiments show that the proposed method is applicable. 相似文献
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In order to obtain competitiveness in the field of industrial manufacture, a reduction in the development period for the small batch manufacture of products is required. In order to meet these requirements, an incremental sheet metal forming process has been developed. In this process, a small local region of a sheet blank deforms incrementally by moving a hemispherical head tool over an arbitrary surface. In this work, an incremental sheet metal forming process controlled three dimensionally by a computer has been accomplished. It has been shown by the experiments that a sheet blank is mainly subject to shear-dominant deformation. Therefore, the final thickness strain can be predicted. The uniformity of thickness throughout the deformed region is one of the key factors to improve the formability in the sheet metal forming processes. Using the predicted thickness strain distribution, the intermediate geometry is decided in the manner that a shear deformation is restrained in the highly shear-deformed region and vice versa. This double-pass forming method is found to be very effective so that the thickness strain distribution of a final shape can be made more uniform. 相似文献
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基于数控渐进成形技术进行板科成形工艺研究,提出完整的渐进成形工艺规划,并将其成功应用于车身装饰件成形.对影响成形的主要参数成形工具头直径d和每层进给量△h进行了分析.为今后完善和发展金属板料数控渐进成形技术起到重要作用. 相似文献
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A new sheet metal forming system based on incremental punching, part 2: machine building and experiment results 总被引:1,自引:1,他引:0
Yuanxin Luo Kai He Ruxu Du 《The International Journal of Advanced Manufacturing Technology》2010,51(5-8):493-506
The paper is the second of the two papers on a new sheet metal forming system of incremental punching. In the first paper, the mechanics model is introduced, and the computer simulations are carried out. This paper consists of two parts: the design and building of an incremental punching machine and experiment results. The machine is a three-axis computer numerical controlled (CNC) machine with a high-speed hydraulic punching head. Given a part, the punch path can be generated using commercial CAM systems with some modifications. Then, the machine takes over forming the part punch by punch. The formability of this system is also investigated giving the maximum forming angle. Following the first paper, two examples are studied in details. The experiment results indicate that the new system is effective for sheet metal rapid prototyping. Finally, some future research topics are discussed. 相似文献
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复杂钣金零件渐进成形方法 总被引:6,自引:0,他引:6
以复杂钣金零件-人面部模型零件为例,论述基于UG软件的建模及建模过程中应注意的问题、支撑模型的制作及其加工代码的生成、适用于渐进成形正成形过程的加工代码生成处理过程,给出加工代码的详细信息,成功加工出质量较高的人面部模型。人面部模型渐进成形试验结果表明,利用渐进成形正成形方法可以成形出形状复杂的钣金零件,生产小批量复杂零件可以节省时间与费用;UG生成的三轴数控加工代码需要通过处理才能应用于渐进成形正成形过程;复杂钣金件渐进成形过程中定位精度非常重要,定位精度高的零件厚度分布符合
的规律,并可以成功成形出设计的零件,定位精度误差较大时零件厚度分布不均匀,成形工具头与板
料的过度挤压侧板料厚度变薄急剧从而引起零件的过早破裂。 相似文献
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实现了具有开放几何特征钣金件的渐进成形。提出采用工艺参数优化、多道次渐进成形和轨迹补偿等方法提高钣金件的几何精度。设计了多道次渐进成形方法的中间构型,目的在于增大材料塑性变形并减小几何偏差。采用层切法轮廓轨迹形成两道次成形中第一道次的构型,为了防止第一道次成形时出现破裂,将非固定方向的成形角度设定为75°,第二道次将非固定方向的板料完全成形。采用基于几何补偿的两道次渐进成形方法可以将开放几何特征钣金件的几何偏差控制在0.5 mm左右。 相似文献
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Harish Kumar Nirala Prashant K. Jain J. J. Roy M. K. Samal Puneet Tandon 《Journal of Mechanical Science and Technology》2017,31(2):599-604
Incremental sheet forming (ISF) is a recently developed manufacturing technique. In ISF, forming is done by applying deformation force through the motion of Numerically controlled (NC) single point forming tool on the clamped sheet metal blank. Single Point Incremental sheet forming (SPISF) is also known as a die-less forming process because no die is required to fabricate any component by using this process. Now a day it is widely accepted for rapid manufacturing of sheet metal components. The formability of SPISF process improves by adding some intermediate stages into it, which is known as Multi-stage SPISF (MSPISF) process. However during forming in MSPISF process because of intermediate stages stepped features are generated. This paper investigates the generation of stepped features with simulation and experimental results. An effective MSPISF strategy is proposed to remove or eliminate this generated undesirable stepped features. 相似文献
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Zemin Fu Wei Chen Xiuli Tian Bingkun Hu 《The International Journal of Advanced Manufacturing Technology》2014,72(5-8):561-570
Based on Hill’s yielding criterion and plane strain condition, the explicit expressions of elastoplastic constitutive model are derived in this paper which takes into account the effects of transverse stress, neutral surface shifting, and sheet thickness thinning on the sheet springback of air-bending. Then, this model is embedded into ABAQUS software platform by means of programming. Finally, 3D ABAQUS finite-element models (FEM), used to form the semiellipse-shaped workpiece with super length and large opening of sheet metal, are established, and the multiple-step incremental air-bending forming and springback processes are simulated. The simulation and experiment results show that the data predicted with the new constructed constitutive model under the plane strain condition are in much better agreement with experimental data than those predicted with the constitutive model built-in ABAQUS. It can be taken as a valuable mathematical tool used for multiple-step incremental air-bending forming simulation of large area sheet metal. 相似文献
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介绍了金属板料数控渐进成形工艺的成形原理、变形分析、直壁筒形件成形的工具路径设计、实验条件及结果分析.根据正弦定律,金属板料数控渐进成形工艺,不能一次成形出直壁筒形件,要成形直壁筒形件,必须进行多次成形.为了尽快逼近直壁筒形件,设计了平行直线型等三种工具路径方案,通过实验和结果分析,找到最佳方案. 相似文献
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金属直壁筒形件数控渐进成形工艺研究 总被引:6,自引:0,他引:6
介绍了金属板料数控渐进成形工艺的成形原理、变形分析、直壁筒形件成形的工具路径设计、实验条件及结果分析。根据正弦定律 ,金属板料数控渐进成形工艺 ,不能一次成形出直壁筒形件 ,要成形直壁筒形件 ,必须进行多次成形。为了尽快逼近直壁筒形件 ,设计了平行直线型等三种工具路径方案 ,通过实验和结果分析 ,找到最佳方案。 相似文献
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Principles and apparatus of multi-point forming for sheet metal 总被引:2,自引:2,他引:0
Chunguo Liu Mingzhe Li Wenzhi Fu 《The International Journal of Advanced Manufacturing Technology》2008,35(11-12):1227-1233
As a flexible forming method for sheet metal part, multi-point forming (MPF) technology is discussed in the paper. It employs two reconfigurable element groups to approximate the continuous upper and lower solid dies. With the technique, rapid fabrication of 3D sheet metal part is realized. The principles of multi-point die forming (MPDF) and multi-point press forming (MPPF) are described and then the rules to determine the size of the element are given. For any spatial shape surface to be formed, all elements’ height can be calculated through the contacting point calculation equation. On the computer control, the shape of the two element groups can be adjusted by serial adjusting mode or parallel adjusting mode. MPDF apparatus that includes CAD software, computer control system, two element groups, hydraulic press and laser CMM is developed. Following the given MPF procedure, 3D sheet metal part was formed without failure. Due to the rapid change characteristics of the two element groups, several special MPF forming techniques that are impossible in conventional sheet forming have been investigated in detail. By flexible blank holder technique, thin sheet MPDF is realized. With sectional MPF, large size sheet would be formed on small scale MPF apparatus. Through closed loop MPF, spring-back would be compensated cycle by cycle, and large deformation part is obtained with incremental MPDF successfully. 相似文献
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Zemin Fu Jianhua Mo Fei Han Pan Gong 《The International Journal of Advanced Manufacturing Technology》2013,64(9-12):1239-1248
There exists some error between the manufactured part shape and the designed target shape due to springback of this part after forming. To reduce the error, an iterative algorithm of closed-loop control for correcting tool path of the single-point incremental forming, based on Fast Fourier and wavelet transforms, has been developed. Moreover, the data of the springback shapes, after unloading, of the sheet metal parts formed with the trial and corrected tool paths, used for iterative correction of tool path in the algorithm, are obtained with finite element model (FEM) simulation. Then, a truncated pyramid-shaped workpiece, whose average errors are +0.183/?0.175 mm, was made with the corrected tool path after three iterations solved by the above algorithm and simulation data. The results show that the tool path correction algorithm with Fourier and wavelet transforms is reasonable and the means with FEM simulation are effective. It can be taken as a new approach for single-point incremental forming of sheet metal and tool path design. 相似文献
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The lifetime of sheet metal forming (SMF) tools is often limited by galling, a wear type that affects the surface quality of the products and the lifetime of SMF tools. Since SMF tools represent high economical value, it is clear that improvement and prediction of tool life is of high industrial importance. Therefore, models are required that can predict friction and wear related phenomena in SMF-processes, in particular galling. This paper demonstrates the application of a wear model, which is able to predict the initiation of galling in lubricated sheet metal forming processes, to laboratory results gained with the TNO slider-on-sheet tribometer. Experiments are conducted with different (coated) tool surfaces, in sliding contact with stainless steel sheet, using two lubricants. By comparing the critical temperature of the generated boundary layer with the flash temperature at the interface of the sheet and individual tool summits, it is possible to predict whether or not galling initiation will occur. It is shown that the laboratory results are in good agreement with the predicted results of the presented wear model. Galling initiation in lubricated sheet metal forming processes, can be avoided by the application of smooth tool surfaces with enhanced thermal conductivity and lubricants which form boundary layers with a high critical temperature. 相似文献
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Jianguang Liu Qiucai Peng Yan Liu Zhongjin Wang 《Journal of Mechanical Science and Technology》2007,21(10):1505-1511
Improving the formability of aluminium alloy sheet metal by using warm or elevated temperature has become a valid approach.
In this paper, viscous pressure bulging (VPB) at warm temperature is proposed. The coupled thermo-mechanical finite element
method and experimental method were used to investigate the VPB of aluminium alloy AA3003 at warm temperature. The temperature
distributions of sheet metal and viscous medium were analyzed for non-isothermal VPB. The influence of forming temperature
on thickness distribution, forming load and failure location of sheet metal were investigated. Research results show the temperature
gradient field in sheet metal forms when the initial temperature of viscous medium is lower than that of sheet metal. The
formability and failure location of sheet metal changes with initial temperature of viscous medium. 相似文献
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Zemin Fu Jianhua Mo Wenxian Zhang 《The International Journal of Advanced Manufacturing Technology》2009,45(5-6):448-458
A mathematical model of springback radius was developed with dimensional analysis and orthogonal test. With this model, the punch radius could be solved for forming high-precision semiellipse-shaped workpieces. With the punch radius and other geometrical parameters of a tool, a 2D ABAQUS finite-element model (FEM) was established. Then, the forming process of sheet metal multiple-step incremental air bending was simulated with the FEM. The result showed that average errors of the simulated workpiece were +0.68/?0.65 mm, and provided the process data consisting of sheet feed rate, punch displacement and springback angle in each step. A semiellipse-shaped workpiece, whose average errors are +0.68/?0.69 mm, was made with the simulation data. These results indicate that the punch design method is feasible with the mathematical model, and the means of FEM simulation is effective. It can be taken as a new approach for sheet metal multiple-step incremental air-bending forming and tool design. 相似文献
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Formability evaluation of a pure titanium sheet in the cold incremental forming process 总被引:2,自引:2,他引:0
G. Hussain L. Gao Z. Y. Zhang 《The International Journal of Advanced Manufacturing Technology》2008,37(9-10):920-926
Owing to its ability to deform a sheet metal locally, the single point incremental forming (SPIF) process produces larger deformations as compared to the conventional forming processes. In the present study, we investigated the effect of some process parameters – pitch, tool diameter, feed rate and friction at the interface between the tool and blank – on the formability of a commercially-pure titanium sheet. Trends between the process parameters and formability are presented in this paper. 相似文献