Principles and apparatus of multi-point forming for sheet metal

Liu, Chunguo; Li, Mingzhe; Fu, Wenzhi

doi:10.1007/s00170-006-0802-1

Cited by 50 publications

(27 citation statements)

References 4 publications

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“…For the concave region, the radius of curvature on any point in sheet (point B) is: (2) In addition, the thickness of sheet can be neglected, as the thickness of sheet is much less than elastic cushion. For the convex hood face (Fig.4-a), middle punches have been pressed in the elastic cushion, when bilateral punches come into contact with sheet in MPSF.…”

Section: Analysis Affecting Forming Accuracymentioning

confidence: 99%

“…Multi-point forming (MPF) [1][2][3] is a flexible manufacturing technique for the forming of three-dimensional surfaces of sheet metals. MPF is dividing the curved surface of the die into many discrete pins, using many punches instead of the traditional dies, and each punch can be controlled by computer so that the enveloping surface of punch group can be changed at any time.…”

Section: Introductionmentioning

confidence: 99%

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Zhang¹,

Liu²,

Fu³

2015

Proceedings of the 2015 6th International Conference on Manufacturing Science and Engineering

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Abstract. A finite element model was built for the sheet metal multi-point stretch forming (MPSF), and the numerical simulation of the MPSF for the saddle and spherical surface workpiece were performed. The simulation results show that，to hyperbolicity workpiece, the influence on precision is different in dissimilar direction, and the reason was analysed. Besides，In MPSF, the contact between sheet and punches group is discontinuous, so it is very important to structure the enveloping surface of punch group. In this paper, four boundary line method was used to describe it to obtain smooth curved face, and B-spline curve was adopted to approach curves in four boundary line method. Finally, the experiment was done to approve the validity of method.

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Section: Analysis Affecting Forming Accuracymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Untitled

Zhang¹,

Liu²,

Fu³

2015

Proceedings of the 2015 6th International Conference on Manufacturing Science and Engineering

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show abstract

“…The basic idea is to replace the traditional rigid fixed-shape stretching die with the discrete multi-point die (MPD) [7]. Because of the MPD is composed of a series of regularly arranged, heightadjustable punch units, different three-dimensional die surfaces can be obtained by adjusting the height of each punch unit that can be controlled by the electrical system [8]. Therefore, the time and the cost of MPSF can be significantly reduced in the process of die designing, manufacturing, repeated debugging, and repairing [9,10].…”

Section: Introductionmentioning

confidence: 99%

Effect of the arrangement of the punch units in multi-point stretch forming process

Jin

Cheng

et al. 2016

Int J Adv Manuf Technol

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Multi-point stretch forming (MPSF), by replacing the traditional rigid fixed-shape stretching die with the multi-point die (MPD), is an important flexible forming technique in sheet metal forming process. However, the particular dimples will be generated on the formed part surface when forming by MPD. In this paper, we prove that the dimple formation can be suppressed by changing the punch units of MPD arrangement. Therefore, the forming effect can be largely improved. Spherical parts are selected as the study objects. Under the same loading condition, two MPSF finite element numerical models are established for conventional arrangement multi-point die (CAMPD) and staggered arrangement multi-point die (SAMPD), respectively. Through the numerical simulations and the stretch forming experiments, the stress, strain, thickness, springback, and shape accuracy are compared between the two parts formed by CAMPD and SAMPD. The results show that the values of the stress, strain, thickness thinning rate, and springback of the formed part are smaller when forming by SAMPD. Moreover, the distributions of the stress, strain, and thickness are more uniform. Also, the surface forming quality and the shape accuracy are improved. These results provide a valuable guidance during developing the new types of MPD.

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“…Plenty of new forming technologies, such as electromagnetic forming [1,2], multipoint forming [3,4], and sheet metal flexible-die forming using different pressuretransmitting mediums [5][6][7], were invented and gain rapid development and wide application in the past decades.…”

Section: Introductionmentioning

confidence: 99%

Effects of viscosity on viscous pressure bulging (VPB) of Al1060 sheet

Yuan

Fang

et al. 2015

Int J Adv Manuf Technol

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The properties of pressure-transmitting medium have a great effect on the formability of sheet metal in sheet flexible-die forming, such as rubber-pad forming and viscous pressure forming (VPF). In this study, viscous pressure bulging (VPB) experiments were used to investigate the effects of viscosity on Al1060 sheet. At the same dome height, the configurations of bulging specimen varied with three different viscosity viscous mediums (1#, 550,000 g/mol; 2#, 700, 000 g/mol; and 3#, 900,000 g/mol). The thickness strain distributions of specimen formed by a higher viscosity medium had a relatively uniform distribution. In order to further study the effects of viscosity on VPB, a CDSB-FEM-EFGM program was used to analyze viscous pressure bulging process. The configuration, stress, strain, and wall thickness distributions of bulging specimen were obtained. The numerical analysis results had a good agreement with the experimental ones, which also showed that properties of the viscous medium had a great effect on the formed specimen. The formability of sheet metal can be further improved through increasing the viscosity of viscous medium.

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Principles and apparatus of multi-point forming for sheet metal

Cited by 50 publications

References 4 publications

Untitled

Untitled

Effect of the arrangement of the punch units in multi-point stretch forming process

Effects of viscosity on viscous pressure bulging (VPB) of Al1060 sheet

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