Method for Internal High-Pressure Deformation of a Blank
The invention relates to an apparatus for the hydroforming of a blank with the aid of a high-pressure fluid, having a die which has a receiving space for a blank, wherein the die has at least one passage which opens out in the receiving space and through which residual fluid located in the receiving space can be transported out of the receiving space. The invention also relates to methods for operating an apparatus for the hydroforming of a blank.
1 - 4 . (canceled)
5 . A method for operating an apparatus for hydroforming a blank with the aid of a high-pressure fluid which includes a die having a receiving space for the blank, comprising:
removing residual fluid which is present in the receiving space from the receiving space through a passage prior to deformation of the blank, and
thereafter feeding lubricant to the receiving space and supplying high-pressure fluid to the interior of the blank.
6 . The method as claimed in claim 5 , wherein removal of residual fluid is assisted by application of a subatmospheric pressure or a superatmospheric pressure to the passage.
7 . The method as claimed in claim 5 , wherein, prior to deformation of the blank, residual fluid located in the receiving space is removed from the receiving space through the passage by feeding lubricant to the receiving space in order to displace the residual fluid, and wherein high-pressure fluid is thereafter supplied to the interior of the blank.
8 . The method as claimed in claim 5 , wherein the lubricant is a low-viscosity lubricant.
9 . The method as claimed in claim 6 , wherein the lubricant is a low-viscosity lubricant.
10 . The method as claimed in claim 7 , wherein the lubricant is a low-viscosity lubricant.