Determination of size-dependent friction functions in sheet metal forming with respect to the distribution of the contact pressure

Vollertsen, Frank; Hu, Zhenyu

doi:10.1007/s11740-008-0130-4

Cited by 40 publications

(23 citation statements)

References 6 publications

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“…A lot of works were carried out concerning the similarity theory [4], the theory of how to transfer the macro forming to micro forming. In contrast to the assumption of the theory of similarity, there are size effects which occur due to the fact that a correct scaling is not possible [5]. A comprehensive review about size effects is given in [6], which shows that there are size effects in the material strength, the lubricated friction and the formability.…”

Section: Introductionmentioning

confidence: 99%

Analysis of punch velocity dependent process window in micro deep drawing

Vollertsen

2010

Prod. Eng. Res. Devel.

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Micro forming is an appropriate technology to manufacture very small metal parts, in particular for bulk production, as they are required in many industrial products resulting from micro technology. Deep drawing provides a great application potential for the manufacturing of parts with complex shapes, even in very small dimensions. Concerning the so called size effects micro deep drawing is widely investigated. However, this process is carried out usually under laboratory conditions with a relatively low punch velocity, for example 1 mm/s. At the same time, the light weight of the forming tools for micro deep drawing makes it possible to vary the punch velocity in a relatively large range. Furthermore, raising the punch velocity is very meaningful for mass production in industry. Thus micro deep drawing with the punch diameter of 1 mm was performed with different punch velocities (1, 10 and 100 mm/ s) in this work, whereby the process behaviour, especially the experimentally acquired process window changes with variation of punch velocities. The analysis in this work shows that the velocity dependent friction coefficients are responsible for the difference in process windows under different punch velocities.

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Section: Introductionmentioning

confidence: 99%

Analysis of punch velocity dependent process window in micro deep drawing

Vollertsen

2010

Prod. Eng. Res. Devel.

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“…Wang and Gong et al 7 , 8 manufactured a series of micro cups with diamond-like carbon (DLC) coated tools. On the other hand, Vollertsen et al 9 optimized an analytical model for acquiring the size-dependent friction function in sheet metal forming. The function was implemented in finite element method (FEM) simulation and validated by comparing the corresponding results with physical experiments.…”

Section: -3mentioning

confidence: 99%

Grain size effect on multi-stage micro deep drawing of micro cup with domed bottom

Wang

et al. 2016

Int. J. Precis. Eng. Manuf.

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A two-stage micro deep drawing system was designed and developed to manufacture a micro cup with domed bottom. The copper blank was annealed at three different conditions to obtain different grain sizes in such a way to study the grain size effect on the deformation behavior and thickness variation of the micro part. To investigate the instantaneous effect and deformation behavior, finite element simulation was used to simulate the whole drawing process. It revealed that the fracture in the place with the thinnest thickness in the micro part drawn from a circle blank with residual stress induced in blanking can be easily happen and the deformation load in the first-stage decreases more than that in the second-stage with the increase of grain size. Moreover, the micro part with a larger grain size has more nonuniform thickness and severer thinning around the punch corner. The surface roughness at the bottom of micro part increases with the grain size. The surface roughness at the wall of it, however, decreases with the deformation stage mainly due to the ironing effect. The research promotes the understanding of grain size effect on multi-stage micro deep drawing and facilitates the development of microforming process.

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“…2 and Table 2. The friction coefficients calculated based on the friction function according to [18,19] are presented in Table 3.…”

Section: Conditions Of Simulation and Experimentsmentioning

confidence: 99%

Minimization of sheet thickness variation and other defects of mini drawn parts using a blank holder plate made from concentric rings

Brabie

Chirita

Albut

2015

Precision Engineering

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Determination of size-dependent friction functions in sheet metal forming with respect to the distribution of the contact pressure

Cited by 40 publications

References 6 publications

Analysis of punch velocity dependent process window in micro deep drawing

Analysis of punch velocity dependent process window in micro deep drawing

Grain size effect on multi-stage micro deep drawing of micro cup with domed bottom

Minimization of sheet thickness variation and other defects of mini drawn parts using a blank holder plate made from concentric rings

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