Outflow Characteristics of a Pressure Medium during Sheet Hydroforming

Hama, Takayuki; Kurisu, Ken; Matsushima, Keita; Fujimoto, Hitoshi; Takuda, Hirohiko

doi:10.2355/isijinternational.49.239

Cited by 12 publications

(15 citation statements)

References 18 publications

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“…10,17) On the contrary, Figs. 5 and 8 show that the effective punch force is almost independent of the hydraulic pressure distribution in the flange area, exhibiting that the fluid-lubrication effect is also independent of the hydraulic pressure in the flange area.…”

Section: Effect Of Outflow Volume On the Fluid-lubricationmentioning

confidence: 84%

“…This difference arises because, at the beginning of the process, a rate of pressurizing the pressure medium during SHF without overcharging is much smaller than that of SHF with overcharging. The pressure medium starts flowing out from the chamber at the pressure peak 10,17) in the both results. After reaching the pressure peak in SHF without overcharging (at a punch stroke of about 4 mm), the variations obtained with the two forming conditions are almost the same until the end of the process.…”

Section: Effective Punch Forcementioning

confidence: 89%

“…In our previous works, we first studied fundamental outflow characteristics during a square-cup SHF process experimentally by directly measuring the hydraulic pressure both in the flange area and in the chamber. 10) We also proposed a numerical model to predict the critical outflow pressure that could be utilized for forming of various shapes. Then we examined the correlation between the sheet deformation and the hydraulic pressure during a square-cup SHF 17) and found that the variation of the hydraulic pressure could be explained well in terms of the sheet deformation.…”

Section: )mentioning

confidence: 99%

“…This forming technology was first studied in detail by Japanese researchers from the 1960s to the 1980s, 18) and nowadays is widely employed in various industries, including the automobile, aerospace, consumer electronics, and kitchen industries. 2,9) Surveys of the literature on SHF can be found in Hama et al 10) and Onder et al…”

Section: Introductionmentioning

confidence: 99%

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Effect of Outflow Volume of Pressure Medium on Fluid-Lubrication Effect during Sheet Hydroforming

et al. 2012

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The effect of the outflow volume of the pressure medium on the fluid-lubrication effect during the sheet hydroforming was investigated experimentally. The hydraulic pressures in the flange area obtained for the sheet hydroforming during which the hydraulic pressure was pressurized using pump were higher than those of the sheet hydroforming during which the pump was not utilized. This might be owing to the difference in the outflow volume of the pressure medium. On the other hand, the drawability of the sheet was almost independent of with or without using pump. Examining the so-called effective punch force, we found that the effect of the difference in the outflow volume of the pressure medium on the fluid-lubrication effect was negligible. We concluded from these results that the fluid-lubrication effect was affected significantly by the existence or non-existence of the outflow of the pressure medium, i.e. the lubricant oil, but it was almost independent of the outflow volume of the pressure medium. Furthermore we also found that the hydraulic pressure distribution in the flange area would not affect the fluid-lubrication effect.

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Section: Effect Of Outflow Volume On the Fluid-lubricationmentioning

confidence: 84%

Section: Effective Punch Forcementioning

confidence: 89%

Section: )mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Outflow Volume of Pressure Medium on Fluid-Lubrication Effect during Sheet Hydroforming

et al. 2012

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“…It is accepted that the counter-hydraulic pressure gives rise to three main features that improve drawability: a friction-increasing effect, a fluid lubrication effect, and a pre-bulging effect. [1][2][3] These three features not only increase the limiting drawing ratio but also offer many other advantages, such as a reduction in tooling costs and improvement in dimensional accuracy. SHF is also applied to low-formability materials, such as aluminum 4) and magnesium, 5) as well as conventional steels.…”

Section: Introductionmentioning

confidence: 99%

Correlation between Sheet Deformation and Hydraulic Pressure Variation during Sheet Hydroforming

et al. 2009

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In our series of studies, the outflow characteristics of a pressure medium used for a sheet hydroforming process have been investigated. The variation of hydraulic pressure during a square-cup sheet hydroforming process was examined, focusing on correlation with sheet deformation. In the initial stage, the outflow of the pressure medium remained stable because a greater extent of pre-bulging arose around the die shoulder just after the process commenced. When the pre-bulging ceased, the pressure medium was sealed in the chamber. Thus, the hydraulic pressure began to increase rapidly within the chamber, and fell in the flange area. The punch stroke at which the hydraulic pressure in the chamber began to rise was highly dependent on the blank holding force because the height of pre-bulging was determined by this force. When the sheet conformed completely to the die shoulder, the pressure medium was also sealed at the shoulder. Therefore, the hydraulic pressure on the die shoulder as well as in the flange area started to fall. The correlation between the critical punch stroke for fracture and the hydraulic pressure in the flange area was also examined.

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Effect of stress distribution on springback in hydroforming process

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2017

Int J Adv Manuf Technol

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Outflow Characteristics of a Pressure Medium during Sheet Hydroforming

Cited by 12 publications

References 18 publications

Effect of Outflow Volume of Pressure Medium on Fluid-Lubrication Effect during Sheet Hydroforming

Effect of Outflow Volume of Pressure Medium on Fluid-Lubrication Effect during Sheet Hydroforming

Correlation between Sheet Deformation and Hydraulic Pressure Variation during Sheet Hydroforming

Effect of stress distribution on springback in hydroforming process

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